Background
Aspirin is an effective anti-platelet agent with proven benefit in preventing atherothrombotic complications. However, resistance to aspirin is significantly associated with increased risk of death, cerebrovascular accident or myocardial infarction compared with aspirin sensitive patients (24% vs 10%, P=0.03) and is well documented in Western literature. It has hitherto not been established in Sri Lanka. Our aim was to estimate the prevalence of aspirin resistance in patients on low dose aspirin for primary or secondary prophylaxis and to ascertain if patients resistant to aspirin have detectable serum salicylic acid levels (SA).