DRUG-TREATMENT ASSOCIATED WITH HEART-VALVE REPLACEMENT

This article reviews a number of specific pharmacological consideratio ns for patients with prosthetic heart valves. All patients with mechan ical heart valves should be anticoagulated. In the past, an Internatio nal Normalised Ratio (INR) of 2.5 to 4.5 has been recommended. Recent nonrandomised studies have suggested that a patient with a prosthetic valve who is at low risk for thromboembolic events could have an INR r anging from 1.8 to 3.5. The lower end of this range should only be use d for patients at higher than average risk of haemorrhage, until rando mised data show that levels below 2.5 may be applied universally. In h ighrisk patients (particularly those with previous thromboembolic even ts) low dose aspirin should be added. During noncardiac surgery, a pat ient at low risk for thromboembolic events could be managed by discont inuing anticoagulation 3 days before the operation, with warfarin reco mmenced as soon as possible afterwards. Perioperative heparinisation w ould be appropriate in a higher risk patient. Women with prosthetic he art valves wishing to become pregnant should be converted to the use o f twice-daily subcutaneous heparin injections. Patients with bioprosth etic valves can be managed without anticoagulation unless they have so me other reason to require it. Patients at high risk should be treated with aspirin or warfarin. Thrombolytic therapy for acute valve thromb osis should be used for those who are haemodynamically compromised and therefore have a high risk of mortality from operative intervention. All patients with prosthetic heart valves undergoing invasive procedur es potentially causing bacteraemia should receive antibiotic prophylax is for endocarditis. The actual drugs used depend on the likely nature of the bacteraemia, and any possible patient hypersensitivity.