Choices in medical management for prevention of acute ischemic stroke

Use of antiplatelet agents for prevention of ischemic stroke

Overall management to lower risk for ischemic stroke is multifaceted. Management includes measures to treat risk factors for accelerated atherosclerosis and stroke, antithrombotic therapies to lower the risk for thromboembolism, and surgery to treat a defined arterial or cardiac lesion. Treatment decisions are made on a case-by-case basis, with most patients receiving some combination of medication and recommendations for lifestyle modification. Some patients will also undergo surgical or endovascular interventions. This article discusses antithrombotic treatment for ischemic stroke prevention, placing major emphasis on the indications for and administration of antiplatelet therapy.

The approach to optimizing stroke care

Stroke is a leading cause of death, disability, and dependence. Treatment of patients with acute stroke requires an integrated, systematic approach with thrombolysis, if indicated, and aggressive supportive care. Subacute treatment of patients with ischemic stroke should focus on the initiation of antithrombotic therapy and prevention of secondary stroke by risk factor modification. Treatment by emergency medicine physicians, who initiate thrombolysis and begin antiplatelet agents, and modification of preexisting risk factors are critical to patient outcome. Because few patients seen in the emergency department are eligible for thrombolysis because of the narrow timeframe for receiving treatment, most patients require antithrombotic therapy with aspirin, clopidogrel, or aspirin in combination with extended-release dipyridamole (ER-DP). Although aspirin, clopidogrel, and aspirin plus ER-DP effectively reduce the risk for recurrent stroke, according to treatment guidelines, clopidogrel alone (particularly in patients allergic to aspirin) and aspirin plus ER-DP are recommended over aspirin alone. Emergency medicine physicians should be aware of the available antiplatelet agents and the importance of antithrombotic therapy for prevention of secondary stroke.

Antiplatelet prescribing patterns for TIA and ischemic stroke: the Indiana University experience

OBJECTIVE

To evaluate antiplatelet prescribing patterns by Indiana University Hospital (IU) neurologists, determine what drives antiplatelet agent decisions, and determine changes made with recurrent cerebrovascular events despite proven antiplatelet therapy. There are now four approved therapies for secondary prevention of cerebrovascular events. As these agents exhibit their effects through different pathways, physicians must choose antiplatelet agents based on other factors.

DESIGN

We retrospectively reviewed charts of neurology patients diagnosed with non-fatal ischemic stroke or TIA at IU from January 1, 1997 to August 31, 2001. Patients were excluded if: discharge diagnosis was not non-fatal ischemic stroke or TIA, they were enrolled in clinical trials, or were placed on anticoagulation therapy with warfarin. Patients' antiplatelet agents at discharge were reviewed to determine if specific factors led to the choice of antiplatelet agent.

RESULTS

A total of 177 patients experienced non-fatal ischemic strokes or TIAs. Of these, 74 were not on prior antiplatelet therapy and 103 were on antiplatelet agents prior to admission. For patients not on therapy, aspirin was the most commonly prescribed agent, with a trend for low-dose aspirin. For patients already on an antiplatelet agent, typically the dose of aspirin was increased or combination therapy initiated.

CONCLUSION

Our experience supports the use of aspirin as a first-line agent for secondary prevention in cerebrovascular disease. For antiplatelet-nai;ve patients, low-dose aspirin is the most frequently used agent. For patients previously on antiplatelet agents, aspirin dosage is increased or clopidogrel is added. High-dose aspirin and ticlopidine use is no longer favored.