Value of Antiplatelet Therapy in Preventing Thrombotic Events in Generalized Vascular Disease

Atherothrombosis is the major underlying cause of acute coronary syndromes, ischemic stroke, and peripheral artery disease, and thus is the leading cause of death and disability in Western countries. Platelet inhibitors play a major role in preventing these ischemic complications. There is strong evidence from the Antiplatelet Trialists' Collaboration meta-analysis that aspirin reduces the combined risk of stroke, myocardial infarction (MI), or vascular death in atherosclerotic patients. The Ticlopidine Aspirin Stroke Study (TASS) compared aspirin and ticlopidine in the secondary prevention of high-risk patients after ischemic stroke and demonstrated a significant advantage for ticlopidine over aspirin. In peripheral arterial disease, the Swedish Ticlopidine Multicentre Study (STIMS) showed that ticlopidine was very effective against placebo. Intravenous antiplatelet agents, such as abciximab, tirofiban, and eptifibitide were also proven effective in acute coronary syndromes and unstable angina. In the Clopidogrel versus Aspirin in Patients at Risk of Ischaemic Events (CAPRIE) trial, clopidogrel was compared with aspirin in patients with symptomatic atherothrombosis regardless of the initial localization of the ischemic event (coronary, cerebral, or peripheral). The efficacy of clopidogrel based on the first occurrence of ischemic stroke, MI, or vascular death showed a relative risk reduction of 8.7% over and above the 25% reduction currently accepted with aspirin (p < 0.05). The greatest benefit of clopidogrel was in the reduction of fatal and nonfatal MI in the most severe groups of patients, providing a 19% relative risk reduction (p = 0.008). The recent disappointing results obtained with oral glycoprotein IIb/IIIa receptor blocking agents may emphasize the need for other antiplatelet combination therapy, such as aspirin-clopidogrel, in coronary disease, stents, stroke, and possibly atherothrombosis in high-risk patients.