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Antibiotic prophylaxis for the prevention of infective endocarditis incongenital heart disease: knowledge ofparents and dentists Chow, Ping-yiu.; 周娉瑤 Chow, P. [周娉瑤]. (2009). Antibiotic prophylaxis for the prevention of infective endocarditis in congenital heart disease : knowledge of parents and dentists. (Thesis). University of Hong Kong, Pokfulam, Hong Kong SAR. Retrieved from http://dx.doi.org/10.5353/th_b4325090 2009

http://hdl.handle.net/10722/56774

The author retains all proprietary rights, (such as patent rights) and the right to use in future works.

A thesis entitled

Antibiotic Prophylaxis for the Prevention of Infective Endocarditis in Congenital Heart Disease: Knowledge of Parents and Dentists

Submitted by

Ping-yiu CHOW

for the degree of Master of Medical Science at the University of Hong Kong in August 2009 1

1. Abstract

Background: Infective endocarditis (IE) is a rare but dreaded infection of endocardium of the heart.

Dental procedures are usually blamed for it, hence

antibiotic prophylaxis given for at risk cardiac patients prior to such procedures. This has been a growing concern over the association between infective endocarditis and dental treatment, and the unnecessary use of antibiotics. Objective: (1) To assess knowledge, attitudes and behaviour of local dentists in relation to congenital heart disease, dental procedures, and infective endocarditis prophylaxis. (2) To assess the knowledge, attitudes and behaviour of parents of children with congenital heart disease in relation to infective endocarditis, dental health and dental procedures. Design: Cross sectional questionnaire survey Subjects: (1) 97 local dentists participated in the survey. The response rate was 52.15%. (2) 202 parents of children with congenital heart disease recruit in tertiary paediatric cardiac centre Results: (1) The subjects of dentist showed adequate ideas on common congenital heart disease, but poor knowledge on some complex ones and their treatment 2

modalities. There is no consensus on the perceived association between oral health/ dental procedures and the risks of infective endocarditis among local dentists. The new american guidelines arouse more awareness from local dental practitioners (64.9%) than the new British guidelines (48.5%). And their practice on antibiotic cover on cardiac patients was found associated with their mode of practice ( P=0.029). (2) 74.8% children subjects brush their teeth twice every day, but over 20% of children had dental caries in the past 12 months. Nearly 70% of their parents have not heard of “infective endocarditis”. The awareness of dental health and complications of congenital heart disease was also found statistically related to the education level of mother (P=0.043) and father (P=0.01), patient’s age (P=0.006), mother’s age (P=0.01) and father’s age (P=0.009). Conclusion: (1) The dentists’ knowledge on congenital heart disease and practices in preventing infective endocarditis were inadequate. Postgraduate education should emphasize the management on patients with congenital heart disease and the guidelines on antibiotic prophylaxis. (2) The parents of children with congenital heart disease have knowledge gaps on infective endocarditis and oral health. It is suggested to promote parental understanding on both infective endocarditis and oral health by health care providers including dentists, with the ultimate aim to impart the knowledge to the patients. 3

2. Introduction

2.1 Infective Endocarditis

Infective Endocarditis (IE) (previously known as subacute bacterial endocarditis) is a rare but dreaded infection of endocardium of the heart, valves, and great arteries with a high mortality and morbidity, even in the new era of advanced imaging, early diagnosis, medical and surgical management. Incidence has still remained constant in the past few decades (Prendergast, 2006).

The pathologic sequence in developing an infective endocarditis is still unclear, but it is believed with the formation of nonbacterial thrombotic endocarditis (NBTE) on the surface of the endothelial damage, transient bacteremia, bacterial adherence, and the proliferation of bacteria within a vegetation (Wilson et al.,2007).

Epidemiology The incidence is about 1.7-6.2 cases/ 100 000 patient years worldwide in the past two decades (Mylonakis et al., 2001). A review of contemporary case series between 1993 and 2003 found the median incidence is 3.6/100 000 population year with an increase with age.

The male: female ratio was found 2:1, while the median

4

in-hospital mortality rate remained relatively high at 16% (Moreillon et al., 2004). An increasing incidence of infective endocarditis in elderly patients has been shown in some recent studies (Tornos et al., 2005, Vahanian, 2003).

Another cohort study in worldwide between 2000 and 2005 showed the median age of patients was 57.9, and one-quarters were associated to recent health care exposure. The mitral (41.1%) and aortic (37.6%) valves were commonly affected.

The risk of

in-hospital death increased with the prosthetic valve involvement, increasing age, pulmonary

edema,

Staphylococcus

aureus

infection,

coagulase-negative

staphylococcal infection, mitral valve vegetation and paravalvular complications (Murdoch et al., 2009).

For paediatric patients, there is a moderate increase in the incidence rate globally (0.5 % children hospitalized in cardiology units) and of its incidence in very young (9% in 1971-1981 vs 17% in 1982-1991). Mortality was found to decrease from 12% in 1971- 1981 to 3 % in 1982-1991 due to the advances of cardiovascular surgery. Congenital heart disease is a major predisposing factor (72% of all cases). (Normand et al., 1995).

However, in developing countries, rheumatic heart disease

predominates, and mortality still remains relatively high (13%) (Sadiq et al., 2001). 5

Previous local research on the epidemiology of infective endocarditis is limited.

A

previous study found the local standardized annual incidence was 2.8/100,000 population year of community acquired infective endocarditis with an increase in relation to age, and it remains stable in the past 10 years. Intravenous drug addict (30%) and chronic rheumatic heart disease (18%) were the most common underlying heart diseases for the disease (Yiu et al., 2006).

Etiological organisms Infective endocarditis can be caused by many pathogenic agents, mostly bacteria. Common causative organisms are Streptococcus viridans and Staphylococus aureus. It can also be caused by other bacterial causes such as enterococci, HACEK organisms, Coxiella and Bartonella, and fungi. (Elliott et al., 2004).

Alpha-hamolytic streptococci in the oral cavity and upper respiratory tract was regarded as the most common organisms causing infective endocarditis in the first half of the 20th century.

However, in the latter half of the century, increasing

incidence of IE was associated with Staphylococcus aureus and coagulase-negative staphylococci, probably due to the extended hospitalizations of the patients (WHO, 2004). 6

The following table (Table 2.1) shows the results of microbiological etiology from International Collaboration on Endocarditis (ICE)- Prospective Cohort Study, Staphylococcus aureus was found to be the commonest causative pathogen in patients with definite endocarditis (Fowler et al., 2006).

(Adapted from Fowler et al., 2006)

7

Risk Factors 1. Predisposing cardiac conditions Cardiac lesions resulting in turbulent flow would increase the incidence of infective endocarditis.

Patients with prosthetic valves and past history of

endocarditis showed 400 times increase in incidence of infective endocarditis. Rheumatic valvular disease, cyanotic congenital heart disease, and degenerative valve lesions are also high risk lesions (Steckelberg et al., 1993).

The

association of congenital heart conditions and infective endocarditis will be discussed in details in section 2.2.

2. Dental procedures and poor oral health Dental procedures causing bacteraemia was blamed for infective endocarditis and so antibiotic prophylaxis have been introduced since 1940’s.

However, more

recent articles support the so-called random bacteraemia resulting from flossing, brushing and chewing is more causative (Seymour et al., 2000, Robert, 1999). The association between dentistry and infective endocarditis will be discussed in details in section 2.3.

8

3. Intravenous drug use Staphylococcus aureus infective endocarditis, associated with intravenous drug use, was mostly community-acquired (Chambers et al., 1983).

4. Nosocomial infection Nosocomial endocarditis was found predominantly to Staphylococcus aureus or coagulase-negative staphylococci.

Intravenous devices may be the source of

bacteria. Improved hygienic standard in operation and prophylactic antibiotics can help prevent such infection (Margaret et al., 1988).

5. Tattoo Infective endocarditis can be triggered by normal flora at the sites of body art. Localized infection at those sites may cause transient bacteraemia (mostly caused by staphylocci), and then seeding in endocardium of the heart (Armstrong et al., 2008).

Diagnosis Duke criteria (Table 2.2) are commonly adopted as the primary diagnostic schema in 9

the diagnosis of suspected patients: Table 2.2 Duke criteria Major criteria : Positive blood culture for Infective Endocarditis Typical microorganism consistent with IE from 2 separate blood cultures, as noted below: • viridans streptococci, Streptococcus bovis, or HACEK group, or • community-acquired Staphylococcus aureus or enterococci, in the absence of a primary focus or Microorganisms consistent with IE from persistently positive blood cultures defined as: • 2 positive cultures of blood samples drawn >12 hours apart, or • all of 3 or a majority of 4 separate cultures of blood (with first and last sample drawn 1 hour apart) Evidence of endocardial involvement Positive echocardiogram for IE defined as : • oscillating intracardiac mass on valve or supporting structures, in the path of regurgitant jets, or on implanted material in the absence of an alternative anatomic explanation, or • abscess, or • new partial dehiscence of prosthetic valve or New valvular regurgitation (worsening or changing of preexisting murmur not sufficient) Minor criteria : Predisposition: predisposing heart condition or intravenous drug use Fever: temperature > 38.0 C (100.4 F) Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, and Janeway lesions Immunologic phenomena: glomerulonephritis, Osler's nodes, Roth spots, and rheumatoid factor Microbiological evidence: positive blood culture but does not meet a major criterion as noted above¹ or serological evidence of active infection with organism consistent with IE Echocardiographic findings: consistent with IE but do not meet a major criterion as noted above Clinical criteria for infective endocarditis requires: • Two major criteria, or • One major and three minor criteria, or • Five minor criteria ¹ Excludes single positive cultures for coagulase-negative staphylococci, diphtheroids, and organisms that do not commonly cause endocarditis

(Adapted from Durack et al., 1994) 10

Treatment Medical treatment for infective endocarditis includes parenteral treatment of antibiotics depending on involved organism and its sensitivity. Supportive care for heart failure is also important.

If the medical treatment fails to cure the infection,

surgery may be the only life-saving procedure available (WHO, 2004).

The

following table (Table 2.3) shows the guidelines for antibiotic treatment of endocarditis by British Society for Antimicrobial Chemotherapy (BSAC) (Elliott et al., 2004).

Table 2.3 Recommendations for empirical therapy of infective endocarditis (IE) Acute presentation: Flucloxacillin (8–12 g iv daily in 4–6 divided doses) plus Gentamicin (1 mg/kg body weight iv 8 hourly,modified according to renal function) Indolent presentation: Penicillin (7.2 g iv daily in 6 divided doses) or ampicillin/amoxicillin (2 g iv 6 hourly) plus Gentamicin (1 mg/kg body weight 8 hourly iv, modified according to renal function) Penicillin allergy, Intra-cardiac prosthesis and Suspected MRSA: Vancomycin (1 g 12 hourly iv, modified according to renal function) plus Rifampicin (300–600 mg 12 hourly by mouth) plus Gentamicin (1 mg/kg body weight 8 hourly iv, modified according to renal function)

(Adapted from Elliott et al., 2004)

11

There are several clear indication for surgery: (1) haemodynamic decompensation due to acute valvar regurgitation; (2) persistent fever and bacteraemia despite appropriate antibiotic treatment; (3) development of abscesses or fistulae caused by local spread of infection; and (4) involvement of microorganisms highly resistant to treatment (for example, fungi, Brucella, Coxiella species) or (5) with potential for rapid tissue destruction (for example, Staphylococcus lugdunensis) (Prendergast, 2006).

2.2 Congenital heart disease and infective endocarditis Infective endocarditis seldom occurs in healthy individuals. In the past 50 years, rheumatic heart disease was the most common condition predisposing to infective endocarditis.

However, mitral valve prolapse and degenerative valvular diseases

have replaced it as the most common predisposing heart condition (Saccente et al., 1996). Moveover, prosthetic valve endocarditis and native valve endocarditis are associated with high rates of in-hospital mortality (Richey, 2008).

The risk of getting infective endocarditis by people with congenital heart lesions is at least 30 folds higher than general population (Steckelberg and Wilson, 1993; Pallasch, 2003).

The risk estimates for infective endocarditis with various heart abnormalities

12

in three recent studies are compared in the following table (Table 2.4). It was found that the patients with previous infective endocarditis, valvular replacement for native valve endocarditis or prosthetic valve endocarditis are in highest risk among other groups of heart diseases (Steckelberg and Wilson, 1993; Pallasch, 2003; Duval and Leport, 2008).

Table 2.4: Risk estimates for infective endocarditis (IE) Incidence of IE

Estimated absolute IE risk resulting from a dental

(per 100000

procedure (per number of procedures)

patient-years) Steckelberg and Wilson, 1993 General population

Pallasch,

Duval and Leport, 2008

2003

5

1 in 14 000 000

-

4.6-52

1 in 1 100 000

-

Congenital heart disease

145-271*

1 in 475 000

-

Rheumatic heart disease

380-440

1 in 142 000

-

-

-

1 in 54 300

308-383

1 in 114 000

1 in 10 700

Previous infective endocarditis

740

1 in 95 000

-

Valvular replacement for

630

-

-

2160

-

-

Mitral valve prolapse

Native valve PCC+ Prosthetic heart valve

Native valve endocarditis Valvular replacement for Prosthetic valve endocarditis *Estimate for congenital aortic stenosis and ventricular septal defect +PCC denotes predisposing cardiac conditions

(Adapted from Ho et al, 2008)

13

2.3 Dental procedures, bacteraemia, and risk of infective endocarditis Poor oral health (especially periodontal disease) and dental procedures could induce bleeding and so were suggested to be the risk factors of infective endocarditis (Guntheroth, 1984).

However, there is no evidence that visual bleeding is a good

clinical predictor of odontogenic bacteraemia.

Bacteraemia can still happen even in

the absence of bleeding (Roberts, 1999).

Some of the dental procedures and daily practice can cause transient bacteraemia, but the magnitude will vary.

The prevalence of bacteraemia arising from dental

procedures and oral daily activity is shown as the following table (Table 2.5) (Seymour et al., 2000).

14

Table 2.5 Prevalence of bacteraemia arising from dental procedures and oral daily

activity Procedure

Prevalence of bacteraemia

Extractions -

Single

-

Multiple

51% 68-100%

Periodontal surgery -

Flap procedure

36-100%

-

Gingivectomy

83%

Scaling and root planning

8-80%

Periodontal prophylaxis

0-40%

Endodontics -

intracanal instrumentation

0-31%

-

extracanal instrumentation

0-54%

Endodontic Surgery -

Flap reflection

83%

-

Periapical curettage

33%

Toothbrushing

0-26%

Dental flossing

20-58%

Interproximal cleaning with toothpicks

20-40%

Irrigation devices

7-50%

Chewing

17-51%

(Adapted from Seymour et al., 2000)

15

The magnitudes of ones from daily practice, such as toothbrushing, flossing and chewing, are found comparable with the listed dental treatments, and such bacteraemia arising from both are proven of low grade intensity compared to the high intensity need for infective endocarditis. In fact in many cases the occurrence of infective endocarditis does not relate to a single dental treatment, instead it is well transpiring that so-called random bacteraemia from daily toothbrushing and flossing is more causative, because the frequency of bacteraemia from daily practice is much than the simple dental procedure (Seymour et al, 2000).

A recent review article has 3 conclusions related to dental-induced bacteraemia: firstly, there is no relationship between post-procedural bleeding and bacteremia. Secondly, the exposure to bacteraemia from daily oral practice is significantly greater than from dental procedures.

Thirdly, the need for antibiotic prophylaxis prior to

dental procedures is questionable (Roberts, 1999).

In another review of 319 legal cases related to dentistry and infective endocarditis, only 83 (26%) successfully established a link with dental treatment (Martin et al., 2007).

The dental procedures associated with those cases were scaling (n=29),

16

extraction (n=28), endodontic treatment (n=12), and minor oral surgery (n=11). It was found a short incubation period of about 9 days in those successful cases, and almost all (80 out of 83 cases) an oral streptococcus was isolated.

Disappointingly,

the involved dental clinicians were found to fail to follow recognized guidelines or keep adequate clinical notes (Martin et al., 2007).

As the incidence of infective endocarditis in patients with predisposing cardiac condition after at-risk dental procedures is extremely low, a huge amount of antibiotic prophylaxis is given to prevent a small number of cases.

It was estimated that about

2.7 million of antibiotics doses are prescribed to prevent 41 cases of native valve infective endocarditis and 39 cases of prosthetic valve infective endocarditis in people with cardiac lesions after at-risk dental procedures (Duval et al., 2006).

2.4 Antibiotic prophylaxis for the prevention of infective endocarditis The recommendations of antibiotic prophylaxis were previously based on limited evidence: few cases of case-controlled studies, extrapolation from animal models, expert opinion, clinical experience and descriptive studies (Wilson et al., 2007).

In

the past 50 years, it was found that the incidence of infective endocarditis has remained consistent after the introduction of antibiotic prophylaxis (Bayliss et al., 17

1983).

Some articles have questioned the causal relationship between dental

procedures and infective endocarditis, and the clinical effectiveness of antibiotic prophylaxis (Duval et al., 2006; Van der Meer et al., 1992). Also so-called random bacteraemia arising from daily activites, such as toothbrush and chewing are proven to be more causative in infective endocarditis than dental-induced bacteraemia (Roberts, 1999).

This shift in opinion is reflected in many international guidelines,

including the ones released from American Heart Association (AHA) and National Institute for Health and Clinical Excellence group (NICE) as discussed in details as follows (Wilson et al,2007; Richey et al, 2008).

American Heart Association guideline Since 1955 the first American Heart Association (AHA) document on prevention of infective endocariditis was published in Circulation, antibiotic prophylaxis was started to introduce for patients at risk before recommended operative procedures (Jones et al, 1955).

The AHA’s latest guidelines were published in Circulation in 2007.

Based on a

comprehensive review of published studies that suggests infective endocarditis is more likely to occur as a result of the everyday activities than from a single dental

18

procedure, and the risks of taking preventive antibiotics (especially bacterial resistance and drug hypersensitivity) outweigh the benefits for most patients, it recommends that only high-risk patients shown in the following table (Table 2.6) need antibiotics as a preventive measure before the at-risk dental procedures in which manipulation of gingival tissue, periapical region of teeth or perforation of the oral mucosa are involved. (Wilson et al., 2007) Table 2.6: The new American Heart Association (AHA) guidelines on prevention of infective endocarditis (IE): AHA guidelines (2007) High-risk cardiac conditions for which antibiotic prophylaxis is recommended 1.

Prosthetic cardiac valve

2.

Previous infective endocarditis

3.

The following congenital heart disease Unrepaired cyanotic congenital heart disease, including palliative shunts and conduits Completely repaired congenital heart defect with prosthetic material or device, whether placed by surgery or by cathether intervention, during the first 6 months after the procedure Repaired congenital heart disease with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device (which inhibit endothelialization)

4.

Cardiac transplantation recipients who develop cardiac valvulopathy

Dental procedure requiring antibiotic prophylaxis for the above cardiac conditions All dental procedures that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa

(Adapted from Wilson et al, 2007)

19

In the previous AHA guidelines published in 1997, underlying cardiac diseases with the risk of infective endocarditis were categorized as high risk, moderate risk and negligible risk.

Antibiotic prophylaxis was recommended for patients in both high

and moderate risk categories as shown in the following table (Table 2.7).

Patients

who have taken prophylactic antibiotics in the past but no longer need them include people with mitral valve prolapse, rheumatic heart disease, bicuspid valve disease, calcified aortic stenosis, congenital heart conditions such as ventricular septal defect, atrial septal defect and hypertrophic cardiomyopathy (Dajani et al., 1997).

Table 2.7: Risk stratification of cardiac conditions associated with infective endocarditis High-risk Category Prosthetic heart valves (mechanical, bioprosthetic, homograft) Previous infective endocarditis Complex cyanotic congenital heart disease Surgically constructed systemic-to-pulmonary arterial shunts or conduits Aortic stenosis Moderate-risk category Most unrepaired congenital heart defects other than those above and below Most repaired congenital heart defects other than those above and below Mitral valve prolapsed with valvar regurgitation or thickened leaflets Rheumatic valvar abnormalities Hypertrophic cardiomypathy (Adapted from Dajani et al., 1997)

Single dose of 2 g amoxicillin for adults/ 50 mg per kg for children 30-60 minutes before procedure is the new regimen.

For patients who are allergic to penicillins or 20

amoxicillin, cephalexin or another first-generation oral cephalosporin, clindamycin, azithromycin, or clarithromycin is also recommended (Wilson et al., 2007). The following table (Table 2.8) shows the recurrent antibiotic regimens for dental procedures. Table 2.8:

Antibiotic prophylaxis regimens for dental procedures Regimen: Single Dose 30 to 60 min Before Procedure

Situation Unable to take oral medication

Agent

Adults

Children

Amoxicillin

2g

50 mg/kg

Ampicillin

2 g IV or IM

50 mg/kg IV or IM

OR Cefazolin or Ceftriaxone

1 g IV or IM

50 mg/kg IV or IM

Allergic to penicillins or

Cephalexin

*+

2g

50 mg/kg

600 mg

20 mg/kg

500 mg

15 mg/kg

1 g IV or IM

50 mg/kg IV or

ampicillin---oral OR Clindamycin OR Azithromycin or clarithromycin Allergic to penicillins or

Cefazolin or Ceftriaxone

IM

amipicillin and unable to take oral medication

OR Clindamycin

600 mg IV or IM

20 mg/kg IV or IM

IM indicates intramuscular; IV, intravenous *

Or other first- or second-generation oral cephalosporin in equivalent adult or pediatric

dosage. +

Cephalosporins should not be used in an individual with a history of anaphylaxis,

angioedema, or urticaria with penicillins or ampicillin (Adapted from Wilson et al., 2007) 21

The working group also pointed out that maintenance of optimal oral health may reduce the incidence of bacteraemia from daily activities and is more important than prophylactic antibiotic to reduce the risk of infective endocarditis (Wilson et al., 2007)

National Institute for Health and Clinical Excellence group guidelines National Institute for Health and Clinical Excellence group guidelines (NICE) released the new guidelines in 2008 that supersedes all other guidelines, such as the British Society for Antimicrobial Chemotherapy (BSAC) guidelines in UK (Richey et al, 2008) .

The trend in recent recommendations by various societies is reducing the misuse of antibiotic prophylaxis for prevention of infective endocarditis.

This British working

group took this trend to the furthest point that recommends abandoning prophylactic antibiotics and chlorhexidine mouthwashes for anyone before dental procedures, because the clinical and cost effectiveness of antibiotic prophylaxis is not proven. Also there is no consistent association between dental procedures and the infective endocarditis development (Richey et al, 2008). Instead, the transient bacteraemias arising from normal daily activities, such as regular toothbrushing and chewing, are 22

more likely to contribute to the larger proportion of cases of infective endocarditis than a single dental visit (Roberts, 1999; Bhanji et al., 2002; Forner 2006).

However, it still advises the use of appropriate antibacterial agents for at-risk cardiac patients with local infections at sites where causative organisms might be present in gastrointestinal or genitourinary procedure.

The following patients with the

following cardiac conditions are being regarded as at risk for infective endocarditis: -

acquired valvular heart disease with stenosis or regurgitation

-

valve replacement

-

structural congenital heart disease, including surgically corrected or palliated structural conditions, but excluding isolated atrial septal defect, fully repaired ventricular septal defect or fully repaired patent ductus arteriosus, and closure devices that are judged to be endothelialised

-

previous infective endocarditis

-

hypertrophic cardiomyopathy.

It has been emphasized that the health care professional should provide clear education to patients at risk about the prevention of IE, rationale of use of antibiotic prophylaxis, the importance of maintaining good oral health, symptoms of IE, and the

23

risks of undergoing invasive procedures (Richey et al, 2008).

There was still a few criticism and debate on this new guideline (Connaughton, 2008), although this is the final regulation in UK that all groups agree with the recurrent guideline.

Also, both American and British working groups have started to

emphasize the important of maintaining good oral health for prevention of IE.

It is

the responsibility for the dentists to deliver good oral care to patients and the patients at risk and their parents should be educated on the oral health in order to prevent infective endocarditis development; however there are inadequate current studies related to it in local dental profession and patients with predisposing heart conditions.

24

2.5 Knowledge and implementation of the guidelines for infective endocarditis prevention by dentists In a study in UK, it was found that knowledge and compliance of dentists with the guidelines was poor (Boyle et al., 2006).

They mostly can identify the dental

procedures but less familiar with the cardiac conditions warranted prophylaxis. It is suggested to provide more undergraduate and postgraduate education detailing advances in cardiology for dentists. In a more recent survey in UK, the dentists in Ireland were unwilling to implement the new NICE guidelines without further information from the patients’ treating physicians, cardiologists or an official Irish body (Riordain et al., 2009).

Welsh dentists showed their level of knowledge on

at-risk cardiac conditions and procedures varied according to the place of work: general dental practices, district general hospitals, and community dental service clinics (Thompson et al., 2007).

In US, both medical and dental practitioners had low compliance (32.9%) with AHA recommendation on endocarditis prophylaxis (Nelson et al., 1989). Another study showed a relatively low knowledge of indication and antibiotic prophylaxis regimen of American dentists (Sadowshy et al., 1988). Local data are nonetheless lacking.

25

2.6 Knowledge of parents of children with congenital heart disease on infective endocarditis Local parents were found to have important knowledge gaps on their children’s heart disease and its complication.

Only 26.9% of them heard of “infective endocarditis”

and 52.4% were aware of the antibiotic cover before dental procedures. About a half recognized dental abscess as a risk factor of infective endocarditis (Cheuk et al., 2004).

However, there are no previous studies on parental knowledge on the

association of dental health and congenital heart disease.

The poor awareness by parents was not unique in the above cohort study. A number of previous studies have reported that a few parents know about infective endocarditis: 47% in Canada (Bulat et al., 2003), 45% in Switzerland (Stucki et al., 2003) and 9.6% in Brazil (da Silva et al., 2002).

In UK, only few at-risk patients received basic

dental hygiene education, even though 58% of them showed evidence of previous or current dental problem.

The dental health was found overlooked in this group of

patients (Balmer et al., 2003).

26

2.7 Aims and Objectives Our study sought to find out the recent practice and understanding for prevention of infective endocarditis by dental professionals in Hong Kong, and to assess the awareness and knowledge of parents of children with predisposing heart diseases on dental health and infective endocarditis.

Such information is believed to be valuable

for local dentists, other health care workers, parents and patients and may be useful in providing a framework and reference point for future surveillance.

Part 1: Dentists The aim is to assess knowledge, attitudes and behaviour of local dentists in relation to congenital heart disease, dental procedures, and infective endocarditis prophylaxis. The objectives are to assess dentists’ knowledge on congenital heart disease and its treatment modalities, to investigate dentists’ attitudes towards dental procedures/ oral health as a risk factor of infective endocarditis in children with congenital heart disease, to determine dentists’ practice on antibiotics prophylaxis for prevention of infective endocarditis with AHA/NICE guidelines as a standard and to determine if the awareness of US/ UK guidelines and their practice on preventing infective endocarditis were associated with dentists’ knowledge, attitude and behaviour on 27

prevention of infective endocarditis. Part 2: Parents of children with congenital heart disease The aim is to assess the knowledge, attitudes and behaviour of parents of children with congenital heart disease in relation to infective endocarditis, dental health and dental procedures.

The objectives are to assess their knowledge of parents of

children with congenital heart disease on the dental health and infective endocarditis, to investigate their attitude towards the interrelationship of their children’s oral health and infective endocarditis, to determine the children’s practice on oral health and their treatment needs and to determine if the profile of the parents of children with congenital heart disease is associated with their knowledge, attitude on dental health and infective endocarditis, and their children’s dental health and practice.

28

3.0 Methods 3.1 Samples Part 1: Dentists All registered dentists should register in the Hong Kong Dental Council under the Dentists Registration Ordinance, Chapter 156, Laws of Hong Kong.

Their

practicing address and related qualification are all released on the annual report and the website of the council (Hong Kong Dental Council).

On the date of

1.7.2008, totally 1854 dentists, including general dental practitioners and specialists in 7 specialties, are found on the list arranging in alphabetical order in members’ surname.

The first one in every ten dentists on the list is selected to

be our target group for the study.

Part 2: Parents of children with congenital heart diseases Grantham Hospital is a specialist hospital providing comprehensive treatment of heart and lung diseases in Hong Kong.

It is the tertiary referral centre for

treatment of heart and lung diseases, and the only hospital in Hong Kong to provide medical care for babies and children with heart diseases (Hong Kong Hospital Authority).

The patients’ parents in its out patient department (OPD)

29

are selected to be the convenient samples of our study. 3.2 Data collection process Part 1: Dentists Totally 186 self-administrated type of questionnaires was sent to local dentists. Individual names and addresses were found from the membership list on the webpage of Hong Kong Dental Council. The survey was anonymous and could be returned in a self-addressed, prepaid envelop included with the questionnaire. There are no follow-up questionnaires.

Part 2: Parents of children with congenital heart diseases In Grantham hospital, the registered nurse in OPD invited 202 parents of children aged 4 to 18 to take part in our survey. administrated.

The format is also self-

Their cardiac diagnosis and treatment received were filled in by

their doctors in charge on the questionnaires.

30

3.3 Questionnaire content A 3-page English questionnaire with a cover letter was sent to the selected dentists, while a 2-page Chinese or English questionnaire was given to the parents by nurse if they agreed to participate.

The items for the questionnaires were chosen based on

numerous review of the literature on similar local surveys (Cheuk et al., 2004).

The

questionnaire format was mainly closed style questions (tick appropriate boxes), which allow simpler and quicker data collection, and also allow easier analysis of responses.

Part 1: Dentists The survey on local dentists was divided into 5 sections: (i) Profile of the respondent, (ii) Knowledge on congenital heart disease and its treatment, (iii)Perceived associations between dental procedures and risk of infective endocarditis in children with congenital heart disease, (iv) Prescription of antibiotics for prevention of infective endocarditis and (v) Awareness on guidelines on antibiotic prophylaxis against infective endocarditis. The Questionnaire is shown as follows:

31

Questionnaire on Congenital Heart Disease, Dental Procedures, and Infective Endocarditis Prophylaxis Part 1: Personal Particulars 1.

Gender: □ Male

□ Female

2.

How long have you practiced dentistry?

□ ≤ 5 yrs □ 6-10 yrs

□ 11-15 yrs

□ 16-20 yrs □ >20yrs 3. □ 4.

Where did you obtain your primary qualification in dentistry (e.g. BDS/DDS/DMD)? Hong Kong

□ overseas, please specify____________

Do you have any additional qualifications approved by Dental Council?

□ Yes , please specify___________________ 5.

□ No

Where do you practice?

□ private sector

□ Government/HA hospital

□ university

□ others, please specify _______________

Part 2: Knowledge on congenital heart disease and its treatment 6.

Do you have an idea on the following congenital heart lesions:

atrial septal defect

□ Yes

□ No

ventricular septal defect

□ Yes

□ No

atrioventricular septal defect

□ Yes

□ No

patent ductus arteriosus

□ Yes

□ No

valvar pulmonary stenosis

□ Yes

□ No

valvar aortic stenosis

□ Yes

□ No

coarctation of the aorta

□ Yes

□ No

interrupted aortic arch

□ Yes

□ No

tetralogy of Fallot

□ Yes

□ No

pulmonary atresia with ventricular septal defect

□ Yes

□ No

pulmonary atresia with intact ventricular septum

□ Yes

□ No

transposition of the great arteries

□ Yes

□ No

truncus arteriosus

□ Yes

□ No

total anomalous pulmonary venous return

□ Yes

□ No

univentricular hearts

□ Yes

□ No

Ebstein’s anomaly

□ Yes

□ No

hypoplastic left heart syndrome

□ Yes

□ No

32

7.

Have you heard of the following treatment modalities for congenital heart disease:

patch repair of septal defects

□ Yes

□ No

surgical valvotomy

□ Yes

□ No

repair of aortic coarctation or interruption

□ Yes

□ No

homograft or valved-conduit surgery

□ Yes

□ No

arterial switch operation

□ Yes

□ No

cavopulmonary shunt/ hemi-Fontan procedure

□ Yes

□ No

Fontan procedure

□ Yes

□ No

Norwood procedure

□ Yes

□ No

transcatheter balloon valvoplasty

□ Yes

□ No

intravascular stenting

□ Yes

□ No

device occlusion of septal defects or ductus

□ Yes

□ No

prosthetic valve replacement

□ Yes

□ No

Part 3: Perceived associations between dental procedures and risk of infective endocarditis in children with congenital heart disease 8. How strong do you think is the relationship between oral health status and infective endocarditis? □ Strong 9.

□

Weak

□ None

□ Don’t know

How strong do you think is the relationship between dental procedures and infective

endocarditis? □ Strong

□

Weak

□ None

□ Don’t know

10. How effective do you think that prophylactic antibiotics would prevent infective endocarditis before dental procedures? □ Very effective

□ Questionable effectiveness □ Not effective □ Don’t know

Part 4: Prescription of antibiotics for prevention of infective endocarditis 11. In which of the following congenital heart patients would you give antibiotic a) Children with acyanotic congenital heart disease before repair

□ Yes

□ No

after surgical or catheter treatment without residual lesion □ Yes

□ No

after surgical or catheter treatment with residual lesion

□ Yes

□ No

before repair

□ Yes

□ No

after repair without residual lesion

□ Yes

□ No

after repair with residual lesion

□ Yes

□ No

b) Children with cyanotic heart disease

33

prophylaxis?

c) after prosthetic valve replacement

□ Yes

□ No

d) history of infective endocarditis

□ Yes

□ No

12. Before which of the following dental procedures do you give antibiotic prophylaxis to children at risk of infective endocarditis? a) Subgingival filling

□ Yes

□ No

b) Supraginigival filling

□ Yes

□ No

c) Scaling

□ Yes

□ No

d) Root canal therapy beyond the root apex

□ Yes

□ No

e) Root canal therapy within the root canal

□ Yes

□ No

f) Extraction

□ Yes

□ No

g) Rubber dam application

□ Yes

□ No

h) Impression taking

□ Yes

□ No

i) Placement of bands/crowns

□ Yes

□ No

j) Tooth reimplantation

□ Yes

□ No

13. Do you refer paediatric congenital heart patients to paediatric cardiologists or family doctors for advice on the use of antibiotics? □ Always

□ Sometimes

□ Never

14. Do you provide education to paediatic congenital heart patients on infective endocarditis prophylaxis? □ Always

□ Sometimes

□ Never

Part 5: Guidelines on antibiotic prophylaxis against infective endocarditis 15. Are you aware of the new US guidelines published in 2007? □ No

□ Yes

If yes, did you change your practice in accordance with the guideline? □ Yes

□ No

16. Are you aware of the new UK guidelines published in 2008? □ No

□ Yes

If yes, did you change your practice in accordance with the guideline? □ Yes

□ No

17. Have you attended any continuing education courses that discuss the recent changes in antibiotic prophylaxis in paediatric congenital heart patients? □ Yes

□ No

Thank you for kindly completing the questionnaire 34

Part 2: Parents of children with congenital heart disease The survey on parents was divided into 3 sections: (i) Profile of patients with congenital heart disease, (ii) Profile of their parents and (iii) Knowledge and practice on dental health.

The Questionnaire for parents is shown as follows in English and Chinese:

35

Questionnaire on Parental Understanding of Dental health and Infective Endocarditis Patient particulars Gum label here 1.

Name: ____________________

2.

Date of birth: _______________ (dd/mm/yy)

3.

Date of questionnaire completion: ______________

4.

Sex: _______

5.

Cardiac diagnosis (fill in by doctors): __________________________________

6.

Surgical or catheter treatment received (fill in by doctors): __________________________________

Parent particulars Marital status: □ Single

□ Married

□ Separated

Who is the respondent?

□ Mother

□ Father

□ Divorced

□ Widow

□ both

Mother Age: _______________ Resident status in Hong Kong: □ HK resident

□ recent immigrant (< 5 years)

□ 2-way visa

Educational level: □ Primary or below

□ Secondary School □ Tertiary education

□ University

Occupation: ______________________ Father Age: _______________ Resident status in Hong Kong: □ HK resident

□ recent immigrant (< 5 years)

□ 2-way visa

Educational level: □ Primary or below

□ Secondary School □ Tertiary education

Occupation: ______________________

36

□ University

Knowledge and practice on dental health 1.

How many times does your child brush every day? ________

2.

Does your child have regular dental check-up (at least once a year)? □ Yes

3.

□ No

In the past one year, did your child have one or more of the following oral conditions? (may choose more than 1 option) □ gum bleeding or swelling □ tooth decay □ tooth exfoliation □ others (please specify) _____________________

4.

Do you concern about possible connections between poor oral hygiene and your child’s heart condition? □ Yes

5.

□ No

Have you discussed with your child’s dentist concerning your child’s oral health and its possible association with heart complications? □ Yes

6.

Have you heard of the condition ‘infective endocarditis’? □ Yes

7.

□ No

Have your child ever had infective endocarditis? □ Yes

8.

□ No

□ No

Have you been told of the importance of antibiotic prophylaxis in children with heart disease undergoing dental procedures? □ Yes

□ No

If yes, by whom? 9.

□ family doctor □ paediatric cardiologist □ dentist

If you have been told about the importance of antibiotic prophylaxis in children with heart disease, do you remember whether your child requires such antibiotic prophylaxis before dental procedure? □ yes □ no □ don’t remember □ never been told about antibiotic prophylaxis 37

問卷調查 患者資料

標籤貼紙 1.

姓名: ____________________

2.

出生日期: _______________ (日/月/年)

3.

完成問卷日期: ______________

4.

性別: _______

5.

心臟病學診斷(由醫生填寫):

6.

__________________________________ 已接受之手術或心導管治療(由醫生填寫) __________________________________

父母資料 婚姻狀況: □ 單身 主要照料者 ?

□ 己婚 □ 母親

□ 分居 □ 父親

□ 離異

□寡婦

□ 父母双方

母親 年齡: _______________ 在港居留身份: □ 香港居民

□ 新來港 人士(少於 5 年)

□ 雙程証

教育水平: □ 小學或以下

□ 中學

□ 高等教育

□ 大學

職業: ______________________

父親 年齡: _______________ 在港居留身份: □ 香港居民

□ 新來港 人士(少於 5 年)

□ 雙程証

教育水平: □ 小學或以下

□ 中學

□ 高等教育

□ 大學

職業: ______________________ 38

牙齒健康的知識和實踐 1.

您的孩子每天刷牙多少次? ________

2.

您的孩子是否接受定期的牙科保健(至少一年一次)? □ 是

3.

□ 否

在過去的一年裏，您的孩子是否有至少一次或以上的下述牙齒的情况? (可選擇一項或以上)： □ 牙齦出血或腫脹 □ 齲齒 ( “蛀牙”) □ 牙齒脫落 □ 其他(請註明) _____________________

4.

您是否關注不良口腔衛生和您的孩子的心臟病之間的聯系？ □ 是

5.

□ 否

您是否曾與您孩子的牙醫討論孩子的口腔衛生以及與之有關的心臟方面的併發 症？ □ 是

6.

您是否聽說過”感染性心內膜炎”? □ 是

7.

□ 否

您的孩子是否曾患感染性心內膜炎? □ 是

8.

□ 否

□ 否

您是否曾被告知預防性抗生素對於有心臟疾患的孩子在接受牙科治療時的重要 性？ □ 是

□ 否

如果有，是誰告知您？ 9.

□ 家庭醫生 □ 兒童心臟科醫生 □ 牙醫

如果您曾被告知預防性抗生素的應用對於有心臟疾患的孩子所起的重要性，您是 否記得您的孩子在接受牙科治療前是否需要應用預防性抗生素？ □ 是 □ 否 □ 忘記 □ 從未被告知 39

3.4

Data analysis

Data were entered as categorical, ordinal and continuous variables accordingly, and were expressed as percentage and 95% confidence intervals. All data analyses were conducted using SPSS (version 11) to determine descriptive statistics.

Frequency

tables and charts are produced to determine the profile, knowledge, attitude and practice of the groups.

Part 1: Dentists The determinants of the use of antibiotic cover among Hong Kong dentists were detected by one-way analysis of variance with a post hoc Tukey-Kramer test. A significance level of P < .05 was used for all analyses.

Part 2: Parents of children with congenital heart disease

The mean difference of patient’s age, mother’s age and father’s age between awareness of oral health and heart complications were detected by unpaired t-test.

The associations of other nominal data (education level and occupation of mother and father, and their interaction with dentist) with the awareness of oral health and heart 40

complications were detect by Chi-square. considered significant.

41

A probability value of p < 0.05 is

4. Results

4.1 Views on congenital heart disease, dental procedures and infective endocarditis prophylaxis by dentists

4.1.1Profile of the group

There were 97 local dentists participated in the survey. The response rate of the study was 52.15% (97/186).

Nearly 80% got their primary dental qualification

(Bachelor of Dental Surgery) from Hong Kong and were working as private practitioners. Table 4.1 shows the demographic variables of the study group.

’

42

Table 4.1:

Demographic variables of the dentists

Dentists

Frequency (%)

Gender Male

69(71.1%)

Female

28(28.9%)

Duration of dental practice: 1.

< 5 years

12(12.4%)

2.

6-10 years

25(25.8%)

3.

11-15 years

13(13.4%)

4.

16-20 years

18(18.6%)

5.

>20 years

29(29.9%)

Primary dental qualification from: 1.

Hong Kong

77(79.4%)

2.

Overseas

20(20.6%)

Additional qualification: 1.

yes

39(40.2%)

2.

no

56(57.7%)

Status of practice: 1. private sector

77(79.4%)

2. government/HA hospital

14(14.4%)

3. university

6(6.2%)

43

4.1.2 Knowledge on congenital heart disease Over 90% claimed to have ideas on 3 common acyanotic heart diseases: atrial septal defect, ventricular septal defect and atrioventricular septal defect.

However, less

than 20% of them knew complex heart diseases such as total anomalous pulmonary venous return, Ebstein’s anomaly and hypoplastic left heart syndrome. following table (Table 4.2) shows their frequency on ideas on those heart diseases.

Table 4.2: Ideas on congenital heart disease among local dentists Congenital heart disease

n

Percentage (95% CI)

1. atrial septal defect

94

96.9% (93.4%-100%)

2. ventricular septal defect

94

96.9% (93.4%-100%)

3. atrioventricular septal defect

90

92.8% (87.5%-98.1%)

4. patent ductus arteriosus

84

86.6% (79.6%-94.0%)

5. valvar pulmonary stenosis

81

83.5% (75.4%-91.6%)

6. valvar aortic stenosis

81

83.5% (75.4%-91.6%)

7. coarctation of the aorta

73

75.3% (65.4%-85.2%)

8. interrupted aortic arch

36

37.1% (21.3%-52.9%)

9. tetralogy of fallot

76

78.4% (69.1%-87.7%)

10. pulmonary atresia with ventricular

25

25.8% (8.7%-43%)

23

23.7% (6.3%-41.1%)

12. transposition of the great arteries

54

55.7% (42.5%-68.9%)

13. truncus arteriosus

25

25.8% (8.6%-43%)

14. total anomalous pulmonary venous

17

17.5% (0-35.6%)

15. univentricular hearts

26

26.8% (9.8%-43.8%)

16. ebstein’s anomaly

12

12.4% (0-31%)

17. hypoplastic left heart syndrome

16

16.5% (0-34.7%)

septal defect 11. pulmonary atresia with intact ventricular septal defect

return

44

The

4.1.3

Knowledge on treatment modalities for congenital heart disease

The study group shows poorer knowledge on treatment modalities for congenital heart diseases than on congenital heart disease. Only patch repair of septal defects and prosthetic valve replacement were known by majority.

Table 4.3: Ideas on treatment modalities for congenital heart disease among local dentist Treatment modalities

n

Percentage (95% CI)

1. patch repair of septal defects

67

69.1% (57.9%-80.1%)

2. surgical valvotomy

50

51.5% (37.6%-65.4%)

3. repair of aortic coarctation or

55

56.7% (43.6%-67.8%)

4. homograft or valved-conduit surgery

30

30.9% (14.4%-47.4%)

5. arterial switch operation

24

24.7% (7.4%-72%)

6. cavopulmonary shunt/hemi-fonstan

16

16.5% (0-34.7%)

7. Fontan procedure

5

5.2% (0-24.7%)

8. Norwood procedure

3

3.1% (0-22.3%)

9. transcatheter balloon valvoplasty

44

45.4% (30.7%-60.1%)

10. intravascular stenting

53

54.6% (41.2%-68%)

11. device occlusion of septal defects or

35

36.1% (20.2%-52%)

91

93.8% (88.8%-98.8%)

interruption

procedure

ductus 12. prosthetic valve replacement

45

4.1.4

Perceived association between oral health/ dental procedures and risk of infective endocarditis in children with congenital heart disease

About a half regarded a strong association between oral health/ dental procedures and the risks of infective endocarditis in patients in congenital heart disease, while about 40% regarded a weak association instead.

It was interesting to note that there is no

consensus on such issue among local dentists.

Table 4.4: Dentists’ attitude on association between oral health/ dental procedures and risk of infective endocarditis in children with congenital heart disease Relationship

Oral health and IE

Dental procedure and IE

n Percentage (95% CI)

n Percentage (95% CI)

Strong

40

41.2% (25.8-56.2%)

40

41.2%(25.8-56.2%)

Weak

48

49.5% (35.4-63.6%)

49

50.5%(36.5-64.5%)

None

6

6.2% (0-25.5%)

3

3.1% (0-22.3%)

Don’t know

3

3.1% (0-22.3%)

5

5.2% (0-24.1%)

46

4.1.5

Perceived effectiveness of prophylactic antibiotics to prevent infective endocarditis

Over a half doubted the effectiveness of prophylactic antibiotics to prevent IE, but over one-third submitted its effectiveness. It is no consensus again among local dentists on effectiveness of prophylactic antibiotics.

Table 4.5: Dentists’ attitude on effectiveness of antibiotic prophylaxis Level of effectiveness of antibiotic

n

Percentage (95% CI)

Very effective

35

36.1% (20.1-50.9%)

Questionable effectiveness

51

52.6% (39.3-66.7%)

Not effective

3

3.1% (0.0%-22.3%)

Don’t know

6

6.2% (0.0%-25%)

prophylaxis

47

4.1.6

Prescription of antibiotics for prevention of infective endocarditis by dentists and its determinants

The 2007 AHA guidelines and 2008 NICE guidelines for prophylaxis regime are used as the standard for comparison of the results. Respondents’ choices based on the guidelines are classified as correct if they are currently following the protocols.

Data

were underlined for correct answers (Table 4.6 and 4.7).

Both of the medical condition and dental procedures requiring prophylaxis are included in the survey.

48

Table 4.6: Prescription of antibiotics by dentists:2007 AHA guidelines as a standard Congenital heart disease:

Yes

No

1. before repair

66, 68%

22,22.7%

2. after surgery or

37, 38.1%

52, 53.6%

73, 75.3%

17, 17.5%

1. before repair

75, 77.3%

14, 14.4%

2. after repair without

39, 40.2%

51, 52.6%

79, 81.4%

9, 9.3%

89, 91.8%

4, 4.1%

91, 93.8%

3, 3.1%

1. subgingival filling

81, 83.5%

16, 16.5%

2. supragingival filling

9, 9.3%

88, 90.7%

3. scaling

84, 86.6%

11,11.3%

4. root canal therapy

72, 74.2%

18, 18.6%

39, 40.2%

52, 53.6%

6. extraction

92, 94.8%

4,4.1%

7. rubber dam

40, 41.2%

56, 57.7%

8. impression taking

11, 11.3%

84, 86.6%

9. placement of

42, 43.3%

52, 53.6%

91, 93.8%

6, 6.2%

Acyanotic congenital heart disease:

catheter treatment without residual lesion 3. after surgery or catheter treatment with residual lesion Cyanotic heart disease

residual lesion 3. after repair with residual lesion After prosthetic valve replacement History of IE Dental procedures:

beyond the root apex 5. root canal therpy within the root canal

application

bands/crowns 10. tooth reimplantation

49

Table 4.7: Prescription of antibiotics by dentists:2008 NICE guidelines as a standard Congenital heart disease:

Yes

No

4. before repair

66, 68%

22,22.7%

5. after surgery or

37, 38.1%

52, 53.6%

73, 75.3%

17, 17.5%

4. before repair

75, 77.3%

14, 14.4%

5. after repair without

39, 40.2%

51, 52.6%

79, 81.4%

9, 9.3%

89, 91.8%

4, 4.1%

91, 93.8%

3, 3.1%

11. subgingival filling

81, 83.5%

16, 16.5%

12. supragingival filling

9, 9.3%

88, 90.7%

13. scaling

84, 86.6%

11,11.3%

14. root canal therapy

72, 74.2%

18, 18.6%

39, 40.2%

52, 53.6%

16. extraction

92, 94.8%

4,4.1%

17. rubber dam

40, 41.2%

56, 57.7%

18. impression taking

11, 11.3%

84, 86.6%

19. placement of

42, 43.3%

52, 53.6%

91, 93.8%

6, 6.2%

Acyanotic congenital heart disease:

catheter treatment without residual lesion 6. after surgery or catheter treatment with residual lesion Cyanotic heart disease

residual lesion 6. after repair with residual lesion After prosthetic valve replacement History of IE Dental procedures:

beyond the root apex 15. root canal therpy within the root canal

application

bands/crowns 20. tooth reimplantation

Responders are given summary scores in Question 11 in the questionnaire regarding 50

the prescription of antibiotics in various congenital heart diseases. If they correct followed the antibiotic prophylaxis in accordance with the new AHA guideline, one score was given for each answers to the responders. Around 40% get 7 scores (Table 4.8). Table 4.8: Summary scores of dentists Scores in Q 11

n (%)

0

1(1.0%)

1

2(2.1%)

2

7(7.2%)

3

2(2.1%)

4

2(2.1%)

5

34(35.1%)

6

11(11.3%)

7

38(39.2%)

8

0(0.0%)

total

97(100%)

The following table (Table 4.9) shows the results of one-way analysis by variance with a post hoc Tukey-Kramer test for identifying the association of the above scores given to dentists and their personal particulars. The mode of practice of dentist is found to be the significant determinants of dentist’s score (P=0.012).

51

Table 4.9: Analysis of determinants of the dentist’s score on following AHA guidelines Dependant variable

P Value

Length of practice

0.56

Place of obtaining the dental degree

0.50

Additional qualification

0.16

Mode of practice

0.029*

*statistically significant

The following table (Table 4.10) shows the distribution of scores by dentist coming from private sector, government/ hospital authority, and university.

It is found that

those from the government/ Hospital Authority perform the best among 3 different groups: they all get at least 5 scores and most of them (71.4%) get 7 scores. Table 4.10: Distribution of the summary score among Hong Kong dentists with different mode of practice Mode of practice scores

Private sector

Government/HA

University

(n=77)

(n=14)

(n=6)

0

1 (1.3%)

0

0

1

2 (2.6%)

0

0

2

6 (7.8%)

0

1 (16.7%)

3

2 (2.6%)

0

0

4

2 (2.6%)

0

0

5

30 (39.0%)

2 (14.3%)

2 (33.3%)

6

9 (11.7%)

2 (14.3%)

0

7.

25 (32.5%)

10 (71.4%)

3

52

(50%)

4.1.7Referral of congenital heart patients to medical colleagues The following pie chart (Fig 4.1) shows the proportion of respondents referring patients to paediatric cardiologists or family doctors for advice on the use of antibiotics. More than 60% of dentists always refer congenital heart patients to medical colleagues.

Figure 4.1: Dentists’ practice on referral of congenital heart patients to medical colleagues

Never: n=5 (5.2%) Sometimes: n=31 (32.0%) Always: n=61 (62.9%)

53

4.1.8 Education to patients The following pie chart (Fig 4.2) shows the proportion of respondents providing education to paediatric congenital heart patients on infective endocarditis prophylaxis. Over 50% always educate their at-risk patients about infective endocarditis, but about one-tenth never.

Figure 4.2: Dentist’s practice on education to patients with congenital heart disease on infective endocarditis and antibiotic cover

Never: n=8 (9.30%)

Always, n=46 (53.49%)

Sometimes: n=32 (37.21%)

54

4.1.9

The awareness of AHA / NICE guidelines of antibiotic prophylaxis against infective endocarditis

The following tables (Table 4.11 and 4.12) show the awareness of two guidelines (AHA /NICE) by local dentists and their accordance with the guidelines.

The new AHA guidelines published in 2007 arouse more awareness from local dental practitioners (64.9%) than the new NICE guidelines published in 2008 (48.5%). correspondingly, for those who were aware of the above guidelines, more dentists changed their practice in accordance with the US guidelines (68.3%) than the UK one (59.6%). Only about 20% of respondents claimed to attend continuing education courses that discuss the recent changes in antibiotic prophylaxis in paediatric congenital heart patients.

Table 4.11: Awareness of AHA guidelines

n

Percentage (95% CI)

Yes

63

64.9% (53.11-76.67%)

No

34

35.1% (18.97-51.03%)

For those who show awareness, their practice

n

Percentage (95%CI)

Yes

43

68.3% (54.06-81.94%)

No

17

27% (5.9-48.1%)

2007 by dentists

is changed in accordance with AHA guideline

55

Table 4.12: Awareness of NICE guidelines

n

Percentage (95%CI)

Yes

47

48.5% (34.71-63.29%)

No

50

51.5% (38.15-65.85%)

2008 by dentists

For those who show awareness, their practice is

n

Percentage (95% CI)

Yes

28

59.6% (41.42-77.78%)

No

15

31.9% (8.31-55.49%)

changed in accordance with NICE guideline

56

4.2 Views of dental health and infective endocarditis by parents of children with congenital heart disease

4.2.1

Profile of the study group

There are 202 parents of children with congenital heart disease participating in this survey.

The age range of patients was from 4.1 to 19.3, with mean age of 12.1+ 4.1.

The mean age of mothers was 42.5 with range from 27 to 56, while that of fathers was 46.53 with range from 25 to 82.

The occupations of the parents are classified according to the International Standard Classification of Occupation into 6 groups: professionals, administrators and managers, skilled workers, service workers, unskilled workers and unemployed. Most of the fathers were administrators or managers (23.76%), and most of the mothers were housewives (43.07%).

The majority of parents received secondary

education. Only four patients in this survey suffered from IE.

Table 4.13 and

Table 4.14 show the demographic and clinical variables of parents and patients respectively.

57

Table 4.13:

Demographic and clinical variables of parents

Parents

Frequency

Responder

Father (n=181)

Mother (n=194)

1. professionals

11 (5.45%)

11 (5.45%)

2. administrators and managers

48 (23.76%)

16 (7.92%)

3. skilled workers

38 (18.81%)

25 (12.38%)

4. service workers

42 (20.79%)

16 (7.92%)

5 unskilled workers

18 (8.91%)

11 (5.45%)

6. unemployed

7 (3.5%)

87 (43.07%)

1. primary or below

20 (9.9%)

43 (21.29%)

2. secondary

115 (56.93%)

123 (60.89%)

3. tertiary non-degree

20 (9.9%)

18 (8.91%)

1. HK resident

180(89.11%)

177 (87.62%)

2.recent immigrant (>5 yrs)

1 (0.50%)

14 (6.93%)

Occupation status

Education level

Resident status in HK

3.2-way visa

3 (1.49%)

0

Marital status 10 (4.95%)

1. single 2. married

166 (82.18%)

3. separated

1 (0.5%)

4. divorced

11 (5.45%)

5. widowed

3 (1.49%)

Respondent: 1. mother

67 (33.17%)

2. father

6 (2.97%)

3. both parents

109 (53.96%)

58

Table 4.14:

Demographic and clinical variables of patients

Patients

Frequency( Percentage)

Sex Male

103(51%)

Female

99(49%)

Diagnosis 1. Atrial septal defect

30(14.9%)

2. Ventricular septal defect

70(34.7%)

3. Atrioventricular septal defect

8(4.0%)

4. Patent ductus arteriosus

9(4.5%)

5. Valvar pulmonary stenosis

18(8.9%)

6. Valvar aortic stenosis

5(2.5%)

7. Coarctation of the aorta

8(4.0%)

8. Interrupted aortic arch

2(1.0%)

9. Tetralogy of fallot

26(12.9%)

10. Pulmonary atresia with ventricular septal

7(3.5%)

defect 11. Pulmonary atresia with intact ventricular

7(3.5%)

septal defect 12. Transposition of the great arteries

6(3.0%)

13. Truncus arteriosus

2(1.0%)

14. Total anomalous pulmonary venous return

1(0.5%)

15. Ebstein’s anomaly

2(1%)

16. Hypoplastic left heart

1(0.5%)

Previous operation/ interventional catheterization: 1. yes

147

(72.8%)

2. no

55

(27.2%)

History of IE: 1. yes

4

(2.0%)

2. no

188

(93.1%)

59

4.2.2

Oral health status and practice

Most children in this survey (74.8%) brush their teeth twice every day, and nearly 70% of them receive regular dental check-up at least once a year.

Gum disease, caries and tooth exfoliation are their common reported oral health problems in the past 12 months. Over 20% of children had dental caries in the past 12 months.

Table 4.15: Self-reported

Frequency (%)

dental problems Gum disease

29

(14.4%)

Caries (decay)

43

(21.3%)

Tooth exfoliation

47

(23.3%)

60

4.2.3

Attitudes and behavior interaction with dentists towards dental health and complications of congenital heart disease, and its determinants

Most of parents (76.7%) are aware of the interrelationship of the oral health and complications of congenital heart disease, but less than half of them (42.6%) once discussed this issue with the children’s dentist. Nearly 70% of them have not heard of “infective endocarditis”.

The following table (Table 4.16) shows the results of analysis by for identifying the determinants of parent’s awareness towards children’s oral health and complications of heart disease. The mean difference of patient’s age, mother’s age and father’s age between awareness of oral health and heart complications were detected by unpaired t-test, while the associations of the education level, occupation of mother and father, and their interaction with dentist with the awareness of oral health and heart complications were detected by Chi-square test. A probability value of p < 0.05 is considered significant.

Those who are aware of the interrelationship of the oral health and complications of congenital heart disease more frequently claimed to discuss this issue with dentists (51.0%), than those who are not aware (16.7%) (P< 0.001). 61

The awareness of dental health and complications of congenital heart disease was also found statistically related to the education level of mother (P=0.043) and father (P=0.01), patient’s age (P=0.006), mother’s age (P=0.01) and father’s age (P=0.009). Parents who were aware of oral health and heart complications were in younger age (mother: mean age 42 v 44.8, father: mean age 45.6 v 50.6), and had younger children (mean age 11.8 v 13.7). More parents who received tertiary or university education would show awareness of this topic too.

62

Table 4.16: Analysis of determinants of parent’s awareness towards children’s oral health and complications of heart disease Awareness of oral health and heart complications Yes

No

(n=154)

(n=42)

Patient’s age (mean age+SD)

11.8+4.0

13.7+4.2

0.006*

Discussion with dentist

78 (51.0%)

7 (16.7%)

90%) are knowledgeable about common acyanotic heart diseases, such as VSD and ASD, while a small percentage of dentists (