What is a clot and why did it happen? • Blood clots are caused by a natural process in which blood cells and fibrin strands clump together to stop bleeding after a blood vessel has been injured • They become dangerous when they block blood flow through an artery or vein • If clots break off from the original site and travel through the bloodstream they can become stuck in another smaller blood vessel and block the blood supply there (embolus) • Warfarin is used to thin the blood, thereby preventing blood clots from enlarging and new clots from forming (thrombi) • Eventually blood clots dissolve over time by natural means
Where did it happen? • Leg: A deep vein thrombosis (DVT) is a blood clot that develops in a deep vein, usually in the leg. This can happen if the vein is damaged or if the flow of blood slows down or stops • Lung: A blood clot usually forms in a peripheral vein and then travels back through the heart to a lung • Heart: A small blood clot from the left atrium could travel to the coronary arteries and cause a heart attack • Brain: A blood clot from the left atrium/ventricle could break off and block one of the arteries to the brain, causing a stroke
Clots can stick to man-made heart valves
• Blood could get trapped and clot on man-made heart valves • Sometimes warfarin is used for six months after tissue valve insertion • The clots could then break off and travel to other parts of the body ¾Recommend patient obtains a MedicAlert bracelet, give form and explain procedure
Atrial Fibrillation (AF)
• With AF the heart beats irregularly causing blood flow to be slowed and blood clots more likely to develop in the atria/heart • Studies have shown that patients with AF who do not take warfarin are at increased risk of stroke
The heart beating normally
The heart beating irregularly a clot can form
What makes clots more likely to happen? • Venous blood clots usually form when blood flow becomes slowed because of damage to the inside of a blood vessel. The following make clots more likely to form: • Sitting or lying in one position for long periods of time (immobility) (e.g. bed rest, air travel): Lack of exercise means that the blood does not flow easily through the veins • Surgery: especially if lasts more than 30 minutes, or involves the leg joints or pelvis • Major injuries, or paralysis • Cancer and its treatments • HRT, oral contraceptives, pregnancy • Being overweight: A substance called leptin is produced by fat cells, which in turn affects blood cells, causing them to stick together • Several inherited conditions
What is a clot and why did it happen? • The brand of warfarin called Marevan® is preferred for use in New Zealand • There is also another brand of warfarin called Coumadin® • Marevan® and Coumadin® are not interchangeable • Always check that you are taking the right warfarin tablet by checking the colour and strength • If your warfarin ever looks different to what you have been having check with your pharmacist to ensure that you are receiving the correct brand and strength
Marevan®
Warfarin 3mg
Warfarin 5mg
Warfarin 1mg
Coumadin®
Warfarin 2mg Warfarin 1mg
Warfarin 5mg
The right dose = the right INR ¾Talk to your patient about his/her individual target INR Target INR according to indication1: • • •
Too high - may bleed
4.0
INR 2.0-3.0: AF, cardioversion, mural thrombus, treatment of DVT or PE INR 2.5-3.5: Mechanical heart valves implanted after 1990 INR 3.0-4.0: Mechanical heart valves implanted before 1990, recurrent DVT or PE whilst on warfarin
3.5 3.0 2.5
2.0
Reference 1. Adult Anticoagulation Guidelines, Middlemore Hospital, CMDHB
¾Consult guidelines for target INR values for patients on dialysis as they may differ from above
1.5
Too low - won’t work © Warfarin Flipchart Group, 2005 This is a clinical guideline only
What is a clot and why did it happen? • The brand of warfarin called Marevan® is preferred for use in New Zealand • There is also another brand of warfarin called Coumadin® • Marevan® and Coumadin® are not interchangeable • Always check that you are taking the right warfarin tablet by checking the colour and strength • If your warfarin ever looks different to what you have been having check with your pharmacist to ensure that you are receiving the correct brand and strength
Marevan®
Warfarin 3mg
Warfarin 5mg
Warfarin 1mg
Coumadin®
Warfarin 2mg Warfarin 1mg
Warfarin 5mg
Blood tests show how many tablets you need •
Before leaving the hospital or doctor’s surgery you will be given a laboratory form and told when to go for a blood test • A house call can be arranged for you if you are unable to go to the laboratory • Phone your doctor in the afternoon for the blood test results (INR) • The doctor will tell you how many tablets to take depending on your blood test • Write your blood test result (INR) in your warfarin book ¾ Ask the patient if they are able to work out how many tablets to take according to their current dose © Warfarin Flipchart Group, 2005 This is a clinical guideline only
Call doctor or nurse if any of the following occurs ¾ Discuss the potential sideeffects with the patient i.e. bleeding such as nose bleeds, blood in urine or stools (black bowel motions), changes to skin, gastrointestinal upsets ¾ Discuss with patients that if they are ill it may alter the effect of their warfarin treatment • Seek medical advice as soon as possible for any unusual bruising or bleeding, severe unexplained pain, fever, vomiting, diarrhoea, infection
•
Any unusual bleeding or bruising
•
Severe unexplained pain
•
Fever, vomiting, diarrhoea, infection © Warfarin Flipchart Group, 2005 This is a clinical guideline only
¾ • • • • •
Warfarin can harm an unborn baby Don’t become
Stress the importance of avoiding pregnancy when taking warfarin: Warfarin crosses the placenta and can cause birth defects if taken in the first three months of pregnancy2;3 Warfarin can cause bleeding in the unborn baby and can also cause severe bleeding in the mother when the baby is born Medical advice must be obtained regarding effective contraception to prevent pregnancy when taking warfarin If the woman suspects she is pregnant while taking warfarin she must contact her doctor urgently If pregnancy is desired by a woman taking long-term warfarin, she must discuss the issue with her doctor before becoming pregnant –Review of anticoagulant management is essential, with counselling to allow informed decision making regarding the risks associated with available anticoagulant options
References 2. Therapeutics in Pregnancy and Lactation. Lee A, Inch S, Finnigan D. Therapeutics in Pregnancy and Lactation. Radcliffe Medical Press; 2000 3. Briggs GG, Freemand RK, Yaffe SJ. Drugs in Pregnancy and Lactation 6th ed. Philadelphia, Md: Lippincott Williams & Wilkins; 2002
pregnant while taking warfarin
Talk to your doctor if you think you might be pregnant © Warfarin Flipchart Group, 2005 This is a clinical guideline only
Warfarin can be used if you are breastfeeding • Warfarin is considered compatible with breastfeeding, because of its poor excretion into milk and consequent lack of effects on the infants3 Reference 3. Briggs GG, Freemand RK, Yaffe SJ. Drugs in Pregnancy and Lactation 6th ed. Philadelphia, Md: Lippincott Williams & Wilkins; 2002
© Warfarin Flipchart Group, 2005 This is a clinical guideline only
Mix your green vegetables with other coloured vegetables •
Eat a balanced diet that includes foods from all food groups • Eat moderate amounts of different coloured vegetables (refer photos); keep daily intake of leafy greens consistent (variations can cause INR fluctuations) • Keep fat intake to a minimum • Avoid dramatic changes in the diet, unless recommended by a health care provider ¾ Advise patients on dialysis to talk to a dietician about diet (photos do not apply to these patients)
© Warfarin Flipchart Group, 2005 This is a clinical guideline only
Small amounts of alcohol only • Alcohol can affect the blood thinning effect of warfarin • Do not exceed two standard drinks per day One standard drink is: • 300ml ordinary-strength beer • 60ml fortified wine (sherry, martini, port) • 30ml spirits (whisky, gin, vodka) • 100ml table wine
¾ Advise patients to avoid binge drinking
© Warfarin Flipchart Group, 2005 This is a clinical guideline only
Avoid activities where you might get hurt easily and bleed too much •
Hazardous occupations or recreational activities may result in injury and bleeding ¾ Stress the need for care if the patient has a job that may lead to injury ¾ Stress the need to avoid sports or activities where injury may result ¾ Advise the patient to make their home environment as safe as possible, (e.g. use a non-slip bath mat, exercise caution when using sharp knives)
© Warfarin Flipchart Group, 2005 This is a clinical guideline only
No new tattoos or piercing ¾Advise patients to avoid having new tattoos or body piercing because of the increased risk of bleeding with warfarin © Warfarin Flipchart Group, 2005 This is a clinical guideline only
No body massage ¾Advise patients to avoid having massage, particularly deep tissue massage, because of the increased risk of bleeding with warfarin © Warfarin Flipchart Group, 2005 This is a clinical guideline only
Tell your dentist that you are taking warfarin before your appointment • Tell your dentist that you are taking warfarin before your appointment • The possibility of bleeding from dental treatment will need to be taken into account by the dentist © Warfarin Flipchart Group, 2005 This is a clinical guideline only
Tell your doctor that you are taking warfarin before any surgery or medical treatment ¾ Stress the need for the patient to discuss the fact that they are taking warfarin before undergoing any surgical or medical procedure to ensure that this is taken into account before, during and after treatment © Warfarin Flipchart Group, 2005 This is a clinical guideline only
Follow these 3 steps: ¾
Revise the key steps involved in taking warfarin:
1.
Having a blood test on an appointed morning Calling the doctor that same afternoon for the INR result Taking the prescribed dose of warfarin at the same time each evening with a glass of water, then recording that the warfarin dose has been taken, e.g. by making a cross on a calendar
2. 3.
1 3
2
© Warfarin Flipchart Group, 2005 This is a clinical guideline only
