Danish Aspirin Resistance Trial - Pilot Study

University of Aarhus

Status

Completed

Conditions

Drug Resistance

Treatments

Drug: acetylsalicylic acid

Study type

Interventional

Funder types

Other

Identifiers

NCT00389129

20060142

Details and patient eligibility

About

Despite treatment with aspirin a large number of patients suffer a myocardial infarction. It has been speculated that these patients might be "resistant" to aspirin, and studies have indicated that this phenomenon is related to a less favourable prognosis. At present, no international consensus exists on how to measure "aspirin resistance". The purpose of this study is to compare different methods for detecting "aspirin resistance". A classic but cumbersome way of evaluating platelet function will be compared to newer, easy-handling point-of-care tests. We hypothesize that one or more point-of-care tests will prove to be superior to the classic platelet function test in detecting aspirin resistance.

Full description

Platelets play a major role in arterial thrombus formation - the cause of cardiovascular death, acute myocardial infarction and ischemic stroke and the number one killer in the Western World. Binding the COX enzyme platelet aggregation is inhibited by aspirin, and as prophylaxis against death, myocardial infarction and stroke aspirin is the most widely used drug worldwide. Low dose aspirin has been shown to improve outcome in patients with ischemic heart disease, but approximately 12% of these patients will suffer from a vascular event during a 2 year follow-up period despite aspirin therapy. It has been speculated that these patients might be "resistant" to the antiaggregatory effect of aspirin, and a diminished response to aspirin has been correlated with a less favourable outcome. However, at present no international consensus exists on how to measure "aspirin resistance".

Comparisons: The platelet aggregation in patients with ischemic heart disease on chronic, low dose aspirin is compared to platelet aggregation i healthy volunteers evaluated with different tests. The traditional way of evaluating platelet function, Platelet Aggregometry a.m. Born, will be compared to 3 point-of-care tests (VerifyNow, PFA-100 and Multiplate Whole Blood Aggregometer) and to urin- and serum thromboxane metabolites as a measure of COX inhibition.

Sex

All

Ages

18+ years old

Volunteers

Accepts Healthy Volunteers

Inclusion criteria

ischemic heart disease verified with a coronary angiogram
treatment with 75 mg aspirin once daily

Exclusion criteria

ischemic vascular event within the previous 12 months
percutaneous coronary intervention or coronary artery by-pass grafting within the previous 12 months
treatment with NSAID, clopidogrel, ticlopidine, dipyridamole, warfarin or any other drug affecting platelet aggregation
platelet count < 120 x 10^9/l
not able to give informed consent