A lower daily dose of aspirin ( < 100 mg ) may be associated with a lower major bleeding risk than higher doses .
Adding antiplatelet therapy , either dipyridamole or low-dose aspirin , to oral anticoagulation decreases the risk of systemic embolism or death among patients with prosthetic heart valves .
The risk of major bleeding is increased with antiplatelet therapy .
These results apply to patients with mechanical prosthetic valves or those with biological valves and indicators of high risk such as atrial fibrillation or prior thromboembolic events .
The effectiveness and safety of low-dose aspirin ( 100 mg daily ) appears to be similar to higher-dose aspirin and dipyridamole .
BACKGROUND Patients with prosthetic heart valves are at increased risk for valve thrombosis and arterial thromboembolism .
Oral anticoagulation alone , or the addition of antiplatelet drugs , has been used to minimise this risk .
An important issue is the effectiveness and safety of the latter strategy .
OBJECTIVES This is an up date of our previous review ; the goal was to create a valid synthesis of all available , method ologically sound data to further assess the safety and efficacy of combined oral anticoagulant and antiplatelet therapy versus oral anticoagulant monotherapy in patients with prosthetic heart valves .
Low-Intensity Oral Anticoagulant Plus Low-Dose Aspirin During the First Six Months Versus Standard-Intensity Oral Anticoagulant Therapy After Mechanical Heart Valve Replacement: A Pilot Study of Low-Intensity Warfarin and Aspirin in Cardiac Prostheses (LIWACAP)
The objective of this study was to evaluate the safety and efficacy of low-intensity warfarin treatment plus aspirin during the first 6 months after surgery in patients undergoing heart valve substitution with mechanical prostheses .  Vitamin K antagonists ( VKA ) are able to reduce but not eliminate thrombosis and systemic embolism in patients with mechanical heart valves . The intensity of treatment and additional use of aspirin in these patients is still controversial . Consecutive patients undergoing aortic or mitral valve replacement ( or a combination of the two ) with mechanical prostheses were invited to participate in the study . After stratifying for site of prosthesis , patients were r and omized to receive low intensity VKA treatment ( target INR 2.5 ) plus aspirin ( 100 mg/day ) for the first six months ( Group A ) or st and ard-intensity ( INR target 3.7 ) VKA treatment ( Group B ) . Mean follow-up was 1.5 years . Principal outcome events were systemic embolism , major bleeding , and vascular death . A total of 94 patients in Group A and 104 in Group B were r and omized and followed up for 144 and 163 patient years , respectively . There were 5 ( 5 % ) events in Group A ( 4 major bleeding events and 1 vascular death ) and 4 ( 4 % ) in group B ( 2 major bleeding events and 2 ischemic stroke ) . All the events except 1 occurred within the first 6 months after surgery . Cumulative incidence of primary outcome events was 5.8 % ( 95 % CI 0.9 to 10.7 ) in Group A and 4.3 % ( 95 % CI 0,2 to 8.4 ) in Group B ( p=0.6 ) . Low-intensity treatment plus aspirin during the first six months after surgery appears to be as effective and safe as moderate-high-intensity anticoagulation
A lower daily dose of aspirin ( < 100 mg ) may be associated with a lower major bleeding risk than higher doses .
Adding antiplatelet therapy , either dipyridamole or low-dose aspirin , to oral anticoagulation decreases the risk of systemic embolism or death among patients with prosthetic heart valves .
The risk of major bleeding is increased with antiplatelet therapy .
These results apply to patients with mechanical prosthetic valves or those with biological valves and indicators of high risk such as atrial fibrillation or prior thromboembolic events .
The effectiveness and safety of low-dose aspirin ( 100 mg daily ) appears to be similar to higher-dose aspirin and dipyridamole .
BACKGROUND Patients with prosthetic heart valves are at increased risk for valve thrombosis and arterial thromboembolism .
Oral anticoagulation alone , or the addition of antiplatelet drugs , has been used to minimise this risk .
An important issue is the effectiveness and safety of the latter strategy .
OBJECTIVES This is an up date of our previous review ; the goal was to create a valid synthesis of all available , method ologically sound data to further assess the safety and efficacy of combined oral anticoagulant and antiplatelet therapy versus oral anticoagulant monotherapy in patients with prosthetic heart valves .