European Journal of Cardio-thoracic Surgery 20 (2001) 747–754 www.elsevier.com/locate/ejcts

Urgent surgical revascularization of unstable angina. Influence of double mammary arteries Massimo Bonacchi a,*, Edvin Prifti b, Gabriele Giunti a, Giacomo Frati b, Guido Sani a a

Department of Cardiac Surgery, University of Florence, 50134 Careggi, Firenze, Italy b I.R.C.C.S NEUROMED, Via Atinense N.18, 86077 (ISERNIA), Pozzilli, Italy

Received 5 April 2001; received in revised form 10 July 2001; accepted 10 July 2001

Abstract Objective: Aim of this study was to evaluate retrospectively: (1) the outcome in patients with unstable angina (UA) refractory to the medical therapy undergoing urgent-emergent CABG; (2) the influence of both IMAs employment. Patients and methods: Between January 1995 and July 2000, 576 (28.5%) consecutive patients with UA underwent CABG procedure. 182 (31.6%, Group I) patients, presenting unstable hemodynamic or angina pectoris refractory to the maximal medical therapy, underwent urgent/emergent CABG. 397 (68.4%, Group II) patients, after the maximal medical therapy did not present angina’s episodes or ECG alterations and underwent elective CABG procedure. Preoperative data were similar in the two groups. Both IMAs were used in 68 (37.4%) patients of I and 152 (38%) of II (P . 0:05) to left side revascularization. Results: CAD extension was greater in Group I: 45 (24.7%) patients presented ischemia in .1 area vs 53 (13.5%) in II (P , 0:001). Incidence of anteroseptal ischemia resulted significantly higher in I (P ¼ 0:017); left main coronary artery stenosis was present in 68 (37%) patients in I vs 108 (27%) in II (P ¼ 0:01). LV function resulted significantly depressed in I, demonstrated by a significantly lower LVEF (P , 0:001), higher NYHA class (P , 0:001) and preoperative incidence of IABP (P , 0:001). Intraoperative data analysis did not reveal any difference between groups. Hospital mortality was 13 (7%) and 21 (5.3%) patients in I and II respectively (P ¼ ns). Multivariate analysis of all preoperative and intraoperative variables revealed the age .65 years (P ¼ 0:01), congestive heart failure (P , 0:001), LVEF , 35% (P ¼ 0:03), .1 ischemic area (P ¼ 0:02) as strong predictors for poor overall survival, and LIMA (P ¼ 0:006) and both IMAs (P ¼ 0:001) as strong predictors for good overall survival. Actuarial survival at 1, 3 and 5 years resulted to be 98.5, 96.5 and 90% in I and 99, 96 and 92% in II (P ¼ ns). Conclusion: CABG has been associated with acceptable outcome in patients with UA which should be applied soonest possible in patients refractory to medical treatment. Total coronary revascularization and employment of both IMAs for left myocardial side are associated with low operative risk and incidence of complications, permit to have acceptable short and long-term outcome in this pool of patients. q 2001 Elsevier Science B.V. All rights reserved. Keywords: Unstable angina; Coronary artery bypass grafting; Emergency surgery; Double mammary arteries

1. Introduction Unstable angina (UA) is one of the most hazardous clinical presentations of the ischemic heart disease, associated with a high incidence of myocardial infarction and poor short-term prognosis [1–3]. The pathophysiological mechanisms in UA include plaque rupture, platelet aggregation and thrombus formation as precipitating events causing coronary artery obstruction and myocardial ischaemia [4]. Actually, UA therapeutic management includes: (i) systemic thrombolysis in combination with inhibitors of platelets aggregation, especially the last generation inhibitors of the GP IIb/IIIA [5–7], and (ii) coronary angioplasty * Corresponding author. Tel.: 139-0338-9855782; fax: 1-39-0554277458. E-mail address: [email protected] (M. Bonacchi).

associated with the eventual stent implantation [8]. Recently, different studies [9–10] have demonstrated better outcome in patients with UA undergoing coronary angioplasty than patients undergoing systemic thrombolysis (early mortality: 4.4% vs 6.5%; reinfarction: 7.2% vs 11.9%; ictus cerebri: 0.7% vs 2%; 5-years mortality: 13% vs 24%; 5-years reinfarction: 6% vs 22%). Despite antithrombotic treatment to prevent further thrombus formation and myocardial infarction, many patients require urgent coronary artery angiography and subsequent revascularization because of persistent chest pain [11,12]. Coronary artery bypass grafting (CABG) procedure in this pool of patients is indicated when the conservative therapies fail to have improvement or when the clinical– anatomical situations necessitate the surgical alternative [1] such as in cases with left main coronary artery disease,

1010-7940/01/$ - see front matter q 2001 Elsevier Science B.V. All rights reserved. PII: S 1010-794 0(01)00917-4

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feasibility and safety of grafting by both IMAs to the left side coronary arteries. 2. Patients and methods

Fig. 1. Timing from the last angina’s episode to the cardiopulmonary bypass initiation in group I patients.

Between January 1995 and July 2000, 576 (28.5%) consecutive patients with UA, from a series of 2025 patients with coronary artery disease (CAD), were treated by surgery at our institution. 2.1. Patients’ population and indications

extended atheromasia of all the coronary arteries, unstable hemodynamic not treatable even with intra aortic balloon pump (IABP). Different studies have clearly demonstrated the benefit of CABG in patients with stable angina, but few reports have analysed the timing and early outcome after the surgical procedure in patients with UA. Other studies report that the risk of early death or acute myocardial infarction is higher after surgery for UA than after elective operations in patients with stable angina pectoris [13–17]. The aim of this study were: (i) to evaluate retrospectively the early and mid-term outcome in patients with UA refractory to the medical therapy undergoing urgent-emergent CABG vs patients with UA responsive to the medical therapy undergoing elective surgery; (ii) to identify the predictors for poor overall and operative survival; (iii) to verify the

All patients presented angina pectoris at rest associated with electrocardiogram alterations but without myocardial enzymatic alterations (GOT, CPK, CPK-Mb and from 1998, Troponine I). All patients underwent coronary angiography. 182 patients (31.6%, Group I) presenting unstable hemodynamic, angina pectoris refractory to the maximal medical therapy (heparin and nitroderivates in continuos endovenous infusion, anti platelets aggregation therapy, calciumblockers or beta-blockers according the case’s clinical presentation), underwent urgent/emergent CABG. The time interval from the last angina’s episode to the cardiopulmonary bypass initiation was less than 3 h in all patients (Fig. 1). The other 397 patients (68.4%, Group II), after the maximal medical therapy did not present angina’s episodes or electrocardiogram alterations. They underwent elective CABG procedure. Preoperative data between groups are

Table 1 Demographic and clinical characteristics a Variables

Total

Group I

Group II

P

Patients Females Mean age Diabetes Hypertension Smoking Dislipidemia Chronic renal failure Cerebral ischemia Peripheral vascular disease COPD NYHA Reoperation Prior myocardial infarction Prior coronary angioplasty Ischemic area Anteroseptal Inferior Lateral No. patients .1 ischemic area Coronary angiography data Three vessel disease Left main coronary artery stenosis LVEF , 35% Intra aortic balloon pump

576 119 (20.5%) 65.3 ^ 9.6 180 (31%) 272 (47%) 217 (37.7%) 215 (37.3%) 43 (7.5%) 11 (2%) 67 (11.6%) 73 (12.7%) 2 ^ 0.7 17 (3%) 151 (26.2%) 143 (25%)

182 30 (16.5%) 66 ^ 10.3 60 (33%) 97 (53%) 82 (45%) 72 (40%) 14 (7.7%) 3 (1.6%) 19 (10,4%) 28 (15.4%) 2.2 ^ 0.6 6 (3.2%) 42 (23%) 48 (26.5%)

397 89 (22.5%) 65 ^ 7.6 120 (30%) 175 (44%) 135 (34%) 143 (36%) 29 (7.3%) 8 (2%) 48 (12%) 55 (14%) 1.9 ^ 0.4 11 (2.8%) 109 (27.5%) 95 (24%)

ns ns ns ,0.048 ,0.014 ns ns ns ns ns ,0.001 ns ns ns

358 (62%) 194 (33.7%) 122 (21.2%) 98 (17%)

126 (69%) 59 (32.4%) 39 (21.4%) 45 (24.7%)

232 (58.4%) 135 (34%) 83 (21%) 53 (13.5%)

,0.017 ns ns ,0.001

464 (80.5%) 176 (30.5%) 67 (11.6%) 41 (7.1%)

151 68 38 23

313 (79%) 108 (27%) 29 (7.3%) 8 (2%)

ns ,0.01 ,0.001 ,0.001

a

(83%) (37%) (21%) (11%)

COPD, chronic obstructive pulmonary disease; NYHA, New York Heart Association; LVEF, left ventricular ejection fraction.

M. Bonacchi et al. / European Journal of Cardio-thoracic Surgery 20 (2001) 747–754

given in Table 1. Patients presenting CPK-MB/CPK .10% and/or Troponine I .0.15 ng/ml, as variables demonstrating myocardial necrosis, were not included in the study. 2.2. Anaesthesia All patients received the same anaesthetic regimen. The premedication was achieved with diazepam (0.1 mg/kg), scopolamine (0.2–0.4 mg), and morphine (0.1 mg/kg). During the operation the electrocardiogram, radial pressure, central venous pressure, pharyngeal and rectal temperature, and urinary output were monitored. The inducement of anaesthesia consisted of fentanyl (25–30 mg/kg), diazepam (0.2 mg/kg), and pancuronium bromide (0.1 mg/kg), and maintained with supplemented dosages of remifentanil hydrochloride (1–3 mg/kg per min), propofol (4–8 mg/kg per h), and low-concentration dosages of isoflurane if necessary. 2.3. Cardiopulmonary bypass and cardioplegia In both groups, cardiopulmonary bypass was instituted using ascending aortic cannulation and two-stage venous cannulation in the right atrium. Heparin was given at a dose of 300 IU/kg to achieve a target ACT of .450 s. The extracorporeal circuit was primed with 1000 ml of Hartmann’s solution, 500 ml of gelofusine, 0.5 g/kg of mannitol, 7 ml of 10% calcium gluconate, and 60 mg of heparin. Non-pulsatile flow was employed in all patients. Intermittent antegrade and retrograde cold blood cardioplegia and normothermia were applied in all patients. 2.4. Surgery All patients underwent longitudinal median sternotomy. The internal mammary arteries were harvested contemporary to the saphenous vein. Before 1997, we have employed the pedunculated IMAs’ harvesting technique (the pleura was opened, the internal thoracic fascia, muscle and fat tissue containing IMA and concomitant veins were incised with the electrocautery along both sides of IMA 0.5–1 cm away; next the pedicle was dissected working from its distal to proximal ends and the major IMA’s branches were clipped by hemoclips; the pedicle was wrapped in gauze soaked with warm papaverine solution; after heparin was administered IMA’s were cut, the distal end was closed by transfixing legation and clumped proximally with a bulldog, and, until the grafting procedure initiation, recovered with the gauze impregnated with papaverine solution). Since 1997 we have introduced the skeletonized IMAs harvesting by an original technique as previously described [18,19]. The mediastinal pleura were dissected gently from the endothoracic fascia, meticulously avoiding their damage; then the endothoracic fascia was incised medially and IMA and both satellite veins were visualised; the IMA was separated from the chest wall and isolated from the fascia; sternal, pericardial and anterior intercostal branches

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were legated with small-sized haemostatic clips frequently only by the IMA side; after heparinization, the IMA conduits were clipped distally, cut, clumped proximally with a bulldog, and, until the grafting procedure initiation, covered with a gauze impregnated with papaverine solution (4 mg/ml), which allowed a pharmacological dilatation. The timing of the IMA’s preparation according the skeletonized technique was reduced day-by-day with dexterity of surgeon (from 42 ^ 18 min in 1997, at 18.5 ^ 11 min in 2000). In both sides of the superior mediastinum the pleurae–pericardial tissues were dissected and the IMA ‘beds’ were created maintaining the pleura integrity. The distal anastomoses, employing polypropylene 7/0 or 8/0 suture and proximal anastomoses of the vein grafts employing polypropylene 5/0 or 6/0 were performed with aorta clamped. The intravenous nitro-derivates therapy was initiated immediately after unclamping the aorta and continued during the postoperative course in the intensive care unit and, according to the hemodynamic situation, eventually combined with diltiazem. In cases with preoperative intra-aortic balloon pumping, IABP was discontinued with the cardiopulmonary bypass initiation and was re-started after the aortic unclamping. 23 (12.6%) patients and 8 (2%) patients in Group I and II respectively necessitated preoperative contrapulsation. In Group I, 15 of 23 preoperatively contrapulsated patients presented unstable hemodynamic status and ischemic electrocardiographic alterations persistent during the initial phase of the operation. In this subgroup of 15 patients, the CPB was initiated immediately and on-pump, the LIMA was harvested in 10 patients (four of them underwent bilateral IMAs harvesting). In 10 from 15 patients with LVEF ,35% (Table 1) presenting a very unstable hemodynamic status, after emergent CPB initiation, the LIMA was employed in 6 patients (2 of them underwent bilateral IMAs harvesting). 2.5. Postoperative data Perioperative myocardial infarction, low cardiac output incidence, intensive care unit stay, complications and early death were determined. Neurological complications were recorded. 2.6. Follow-up The mean follow-up time was 2.7 ^ 1.4 years (range 6– 63 months). Survival status was determined by contacting all patients or next by telephone. 2.7. Definitions Hospital mortality was defined as death for any reason occurring within 30 days after operation. Perioperative myocardial infarction was defined as the appearance of new Q-waves or significant loss of R-wave forces peak creatine phosphokinase MB fractions greater than 10% of

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total CK. Low cardiac output syndrome was defined as a cardiac index ,2.0 l/min per m 2, requiring pharmacological support and/or contrapulsation. Postoperative renal dysfunction was defined as an increment of creatinine level $1 mg/dl compared to the preoperative value. Gastrointestinal complications included confirmed diagnosis of upper and lower gastrointestinal haemorrhage, intestinal ischemia, acute cholecystis and pancreatitis. 2.8. Statistical analysis Group statistics were expressed as mean ^ SD. The generalized Wilcoxon test was performed for the statistical analysis between groups. Fisher’s exact test was used for the non-continuous variables. The relationship between preoperative and postoperative variables within the same group was assessed by the McNemar test. Multivariate analysis by Cox regression was applied: the age was included in the models as a continuous variable and all other variables as dichotomous variables. Variables that did not present significance in the multivariate analysis were excluded from the final model. Survival was calculated using the Kaplan–Meier method. Significance between data was considered achieved when P , 0:05. 3. Results Preoperative data analysis revealed a higher incidence of hypertension and smoking in Group I compared to Group II (P , 0:048 and P , 0:014, respectively). The other risk factors and associated pathologies, the incidence of myocardial infarction and prior PTCA, were similar between groups (Table 1).

CAD resulted more extent in I: 45 (24.7%) patients presented ischemia in .1 area vs 53 (13.5%) in II (P , 0:001). Incidence of anteroseptal ischemia, demonstrated by electrocardiogram data analysis, resulted significantly higher in I (P , 0:017). Left main coronary artery stenosis was present in 68 (37%) patients in I vs 108 (27%) in II, P , 0:01. Left ventricular function resulted significantly depressed in I, demonstrated by lower LVEF (P , 0:001), higher New York Heart Association functional class (P , 0:001) and preoperative IABP employing (P , 0:001) (Table 1). Mean interval time between the last angina’s episode and the cardiopulmonary bypass initiation in Group I patients was 136 ^ 40 min, and in each case less than 3 h (Fig. 1). Intraoperative data analysis did not reveal any difference between groups (Table 2) except the IMAs harvesting time which resulted to be 19 ^ 7.5 min in I vs 33 ^ 13 min in II (P , 0:001). CBP time in I was 87 ^ 12 vs 90 ^ 27 min in II (P ¼ ns) and the aortic cross-clamping time resulted 46 ^ 9 and 48 ^ 13 min in I and II, respectively. In patients receiving bilateral IMA grafts (68 in I and 152 in II) the right IMA was used to bypass a branch of the left coronary system: obtuse marginal artery (72% in I and 75% in II), diagonal branch of the left anterior descending artery (8% in I and 8% in II) and intermediate coronary artery (20% in I and 17% in II). In cases undergoing bilateral IMAs harvesting, the conduit route for RIMA was through the transverse sinus. In total 3 ^ 0.4 and 3.1 ^ 0.5 distal anastomoses per patients and 1.4 ^ 0.5 vs 1.5 ^ 0.7 arterial grafts per patient were employed in I and II respectively (P ¼ ns). Hospital mortality was 13 (7%) and 21 (5.3%) patients in I and II, respectively (P ¼ ns). Main causes of hospital mortality resulted: perioperative myocardial infarction (six and nine

Table 2 Operative data a Variables

Group I (n ¼ 182)

Group II (n ¼ 397)

P

Cardiopulmonary bypass time (min) Aortic cross-clamping time (min) IMA harvesting time (min) Number of distal anastomoses Sequential anastomoses Left internal mammary artery Right internal mammary artery Grafted to the OMA Grafted to the DA Grafted to the ICA Bilateral IMA Arterial grafts/patients Associated surgical procedures Carotid artery endarterectomy Cholecystectomy Postoperative surgical procedures Revision for DSWI Surgical revision for bleeding Intestinal resection

87 ^ 12 46 ^ 9 19 ^ 7.5 3 ^ 0.4 18 (10%) 162 (90%) 68 (37.4%) 49 (72%) 5 (8%) 14 (20%) 68 (37.4%) 1.4 ^ 0.5

90 ^ 27 48 ^ 13 33 ^ 13 3.1 ^ 0.5 31 (7.8%) 338 (85%) 152 (38%) 114 (75%) 12 (8%) 26 (17%) 152 (38%) 1.5 ^ 0.7

ns ns , 0.001 ns ns ns ns ns ns ns ns ns

15 (8.2%) 6 (3.3%)

28 (7%) 17 (4.2%)

ns ns

3 (1.6%) 8 (4.4%) 1 (0.5%)

9 (2.2%) 16 (4%) 3 (0.75%)

ns ns ns

a IMA, internal mammary artery; OMA, obtuse marginal artery; DA, diagonal branch of left descending artery; ICA, intermediate coronary artery; DSWI, deep sternal wood infection.

M. Bonacchi et al. / European Journal of Cardio-thoracic Surgery 20 (2001) 747–754 Table 3 Underlying causes of hospital death Variables

Cardiac causes Acute myocardial infarction Aortic dissection Low cardiac output Non-cardiac causes Multi organ failure Respiratory failure Infection Stroke Bleeding

Group I (n ¼ 13) no. (%)

Group II (n ¼ 21) no. (%)

P

6 (46%) 0 2 (15.4%)

9 (43%) 1 (4.8%) 3 (14.3%)

ns ns ns

3 (23%) 0 0 1 (7.7%) 1 (7.7%)

3 (14.3%) 1 (4.8%) 1 (4.8%) 1 (4.8%) 2 (9.6%)

ns ns ns ns ns

patients in I and II, respectively). Causes of early death are given in Table 3. Postoperative IABP duration and inotropes’ use resulted significantly higher in Group I (P , 0:001 and P , 0:027, respectively). Incidence of perioperative myocardial infarction, intensive care unit stay, mechanical ventilation and other postoperative complications were similar between groups (Table 4). There was no statistically significant difference between patients receiving single and bilateral IMA grafts in the incidence of reoperation for bleeding, deep sternal wound infection, respiratory insufficiency or prolonged mechanical ventilation and perioperative myocardial infarction. All patients were followed for a mean period of 2.7 ^ 1.4 years. Actuarial survival at 1, 3 and 5 years resulted to be 98.5, 96.5 and 90% in Group I and 99, 96 and 92% in Group II (P ¼ ns) (Fig. 2). At follow-up nine (5.3%) patients in I and 17 (4.5%) in Group II presented angina pectoris (P ¼ ns). All received only one mammary artery. RedoCABG was performed in six (3.5%) patients in I and 8 (2%) in II (P ¼ ns) (Table 5). Multivariate analysis of all preoperative and intraoperative variables revealed age . 65 years (P , 0:01), congestive heart failure (P , 0:001), LVEF , 35% (P , 0:03),

751

.1 ischemic area (P , 0:02) as strong predictors for poor overall survival, and LIMA (P , 0:006) and both IMAs (P , 0:001) as strong predictors for good overall survival (Table 6). 4. Discussion The incidence of UA in different reported cohort of CAD patients undergoing CABG is 28.5–47.8% [20], significantly higher than reported series of patients with CAD not surgically treated (10–15%) [21]. Even in our series of 2025 consecutive patients, 576 (28.5%) presented UA. It seems that the surgical approach towards this risky and unexpected clinical manifestation remains the best and safest therapeutic treatment even though other alternative solutions, such as new pharmacological protocols, coronary angioplasty with intracoronary stent implantation, have demonstrated excellent outcome [6,7,10]. Different studies have already demonstrated that medical therapy alone can give some acceptable short-term outcome in only 75% of patients with UA [1,5,7]. Coronary angioplasty, which can be performed only in selected patients, is associated with a cumulative procedure related mortality and myocardial infarction of 2–10% [8,22,23] and with a short-term restenosis incidence within the first 6 months of 25–45% [10,22,23]. Surgical treatment of UA is reserved for cases refractory to medical therapy, when coronary angioplasty is not possible: diffuse CAD, left main coronary artery stenosis, depressed left ventricular function. Certainly all these conditions increase significantly the operative risks and reduce the postoperative outcome. In our series of 576 patients we have had a successful postoperative result in 94.5% of cases, similar to other analogous series of patients with UA reported in the literature [1,20,22]. Main goal of this study was to evaluate the efficacy and safety of urgent/emergent CABG, particularly the employ-

Table 4 Postoperative survival and morbidity a Variables

Group I (n ¼ 182)

Group II (n ¼ 397)

P

Intensive Care Unit stay (h) Mechanical ventilation (h) Total hospital stay (stay) Postoperative IABP (preop. not included) IABP duration (h) Perioperative AMI Inotropes use (Dopamine .6g/kg per min) Bleeding .1000 ml Postoperative ultrafiltration/hemodyalisis Pulmonary complications Gastrointestinal complications Neurological complications Multi organ failure Hospital mortality

27 ^ 11 18.6 ^ 9.5 11.4 ^ 6.3 10 (5.5%) 49.4 ^ 17.7 16 (8.8%) 42 (23%) 19 (10%) 11 (6%) 9 (5%) 4 (2.2%) 5 (2.7%) 3 (1.7%) 13 (7%)

25 ^ 15 17 ^ 10 10.5 ^ 5.5 18 (4.5%) 40 ^ 18 26 (6.6%) 60 (15%) 45 (11.3%) 21 (5.3%) 18 (4.5%) 8 (2%) 11 (2.8%) 4 (1%) 21 (5.3%)

ns ns ns ns , 0.001 ns , 0.027 ns ns ns ns ns ns ns

a

IABP, intra aortic balloon pump; AMI, acute myocardial infarction.

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M. Bonacchi et al. / European Journal of Cardio-thoracic Surgery 20 (2001) 747–754 Table 6 Risks of early and mid-term death a Variables

Age 65–70 years Congestive heart failure LVEF , 35% . 1 ischemic area Reoperation ACC . 70 min LIMA Bilateral mammary artery

Overall deaths

Operative deaths

OR 95%–CI P

OR 95%–CI P

2.2 2.4 2.6 0.7 2.3 1.9 3.2 2

1.8 2 1.8 1 2.7 2.1 2.7 1.8

1.4–4.2 1.7–4.5 0.9–4.9 0.6–1.5 2–4.1 1–3.9 1.2–5.7 0.8–4.2

0.01 0.001 0.03 0.02 0.12 0.08 0.006 0.001

8–3.9 1.6–3.9 1–3.9 0.8–1.8 1.8–4.5 1.3–4.2 1–4.9 0.7–4

0.03 0.005 0.002 0.14 0.02 0.004 0.15 0.003

a LVEF, left ventricular ejection fraction; ACC, aortic cross-clump; LIMA, left internal mammary artery

Fig. 2. Overall actuarial survival in both groups.

ment of double IMAs, in patients with UA refractory to maximal medical therapy. Preoperatively these patients presented a greater CAD extent and more depressed left ventricular function. Operative data analysis did not reveal any difference between groups, except the IMAs harvesting time which resulted to be significantly lower in patients undergoing urgent/emergent CABG, probably because during such critical situations the ‘surgeon’s concentration’ is higher, and as a consequence the harvesting procedures’ timing is speeded up significantly. Postoperatively, inotropes drugs use and IABP duration were significantly higher in patients undergoing urgent/emergent CABG. Even this difference, seems due to the preoperatively more depressed left ventricular function and unstable hemodynamic in patients undergoing urgent/emergency CABG. Hospital mortality resulted higher in this pool of patients but not statistically different vs patients undergoing elective surgical procedure. Sixty-eight percent of hospital deaths were from cardiac causes. Bjessmoa et al. [23] found almost 85% of the early deaths due to cardiac causes. In the same series were identified 13% perioperative non-fatal myocardial infarctions. The higher incidence of perioperative myocardial infarction and cardiac death is probably related to perioperative myocardial protection techniques. We employed in all patients intermittent antegrade and retrograde cold blood cardioplegia and normothermia. Only Table 5 Survival and morbidity at mean 2.7 ^ 1.4 years follow-up Variables

Group I (n ¼ 169)

Group II (n ¼ 376)

P

Major cardiac events Angina pectoris Redo CABG Cardiac transplantation

13 (7.7%) 9 (5.3%) 6 (3.6%) 2 (1.2%)

22 (6%) 17 (4.5%) 8 (2%) 4 (1%)

ns ns ns ns

25% and 50% of patients reported in the series of Bjessmoa et al. [23] underwent retrograde cold blood cardioplegia or combined antegrade and retrograde cold blood cardioplegia, respectively. We believe that this myocardial protection strategy during surgical coronary revascularization procedure should be taken into consideration, especially when both in situ IMAs are employed, this due to difficulties of cardioplegia delivering through the antegrade flow, instead of a better cardioplegia delivering to the suffering myocardial territories through the retrograde flow. Louagie et al. [16] found that low cardiac output caused 69% of hospital deaths in patients operated on for UA. The main cause was the perioperative myocardial infarction. Reported rate of perioperative myocardial infarction in the literature ranges from 4 to 17% [15]. It has to be said that cardiac causes such as low cardiac output have contributed to other fatal outcome in patients listed to have multiple organ failure, stroke or infection as the underlying cause of death. At follow-up we found a cumulative overall survival at 5 years of 90% in patients undergoing urgent/emergent CABG and 95% in those undergoing elective surgery. Ninety-five percent of all patients did not present major cardiac events at follow-up, a better result than the outcome after the non-surgical alternative employment [1,10,24]. Predictors for poor overall outcome seem: depressed left ventricular function, older age and more extensive CAD. Furthermore, operative mortality increased in case of reoperation and longer aortic cross-clamp time, which often reflect more extensive CAD (multiple distal anastomoses and technical difficulties). The use of IMAs in patients with unstable angina undergoing urgent/emergent CABG is not defined yet, this due to a scarcely employment of such conduits in critical conditions secondary to longer harvesting IMAs’ time vs saphenous vein. The IMAs are the conduit of choice in CABG because of superior graft patency, reduced cardiac events, enhanced short-term and long-term survival and well documented long-term patency rate [25]. Since 1996 we have

M. Bonacchi et al. / European Journal of Cardio-thoracic Surgery 20 (2001) 747–754

started to employ bilateral skeletonized IMA for grafting the left coronary system [18,19] and, later on, after 1997, we have expanded that use also in urgent/emergent situation as, for example, in patients with untreatable angina or critical hemodynamic status. In such situations, we prefer to put the patient on extracorporeal circulation as soon as possible, and if the electrocardiographic alterations disappear, we prefer to spend some few minutes more on cardiopulmonary bypass for one or both IMAs’ harvesting, keeping in consideration the important long-term advantages of such conduits. The extra time necessary for IMA’s harvesting has been reduced significantly with growing surgical experience and the employment of the in situ IMAs reduces, in itself, the cardiopulmonary bypass and aortic cross-clamping times, because such grafts does not necessitate proximal anastomosis to the ascending aorta. We believe that a careful patient’s management, even in unstable conditions, and shorter IMAs harvesting time, permits to employ successfully such arterial conduits even in critical clinical situations. Moreover, employment of both IMAs in the reported pool of patients seems to increase significantly the overall survival and improve freedom from MI and recurrent angina. Arterial grafts employment, with a documented long-term patency, was not associated in this series of patients with an increment of the hypoperfusion syndrome or an increased low cardiac output incidence. It seems that patients with UA have same operative and longterm predictors for poor outcome as general population undergoing CABG. The outcome of this study is similar to other reports which demonstrated that early year of surgery, urgent surgery, female gender, increasing age, aortic cross-clamp time, depressed left ventricular function, reoperation, number of diseased vessels, pre-operative IABP, left main stenosis and pre-operative myocardial infarction increase the risk of early death after surgery for UA [16]. We may conclude that CABG seems associated with acceptable outcome in patients with UA which should be applied soonest possible in case of refractivity to the medical treatment. A total coronary revascularization and employment of both IMAs permit to have better short and long-term outcome in this pool of patients. CABG performed in urgency or emergency condition is associated with a higher perioperative risk but acceptable postoperative morbidity and mortality. A proper perioperative myocardial protection significantly reduces the perioperative myocardial infarction and hospital death. Predictors for poor overall outcome in patients with UA are similar to the general CAD population undergoing coronary revascularization. References [1] Conti RC. Risk stratification in unstable angina: how to select patients who need emergency revascularization. J Card Surg 1993;8:391–395. [2] Kennon S, Suliman A, MacCallum PK, Ranjadayalan K, Wilkinson P, Timmis AD. Clinical characteristics determining the mode of presen-

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