Antiplatelet monotherapy is effective for stroke prevention in patients who have suffered lacunar stroke, and there currently exists no role for long-term dual antiplatelet therapy in these patients, according to a large new meta-analysis in Stroke (April 2015).
The effectiveness of antiplatelet therapy in patients with lacunar stroke has been a topic of controversy. The current guidelines on the use of antiplatelet agents for secondary stroke prevention rely on data from randomized controlled trials designed to assess the efficacy of these agents in all ischemic stroke subtypes.
However, lacunar strokes result predominantly from an underlying vascular pathology—intrinsic disease of penetrating cerebral arterioles. This is different from other stroke subtypes. These biological differences have led some physicians to question the benefit of antiplatelet therapy in patients with lacunar stroke, particularly in view of their shared vascular pathology with cerebral microbleeds and intracerebral hemorrhage.
“Subgroup analyses of the randomized controlled trials had previously suggested therapeutic effect in patients with lacunar stroke,” said study author Ashkan Shoamanesh, MD, Assistant Professor of Medicine (Neurology) at McMaster University in an interview with Practical Neurology™. “Accordingly, we were not particularly surprised by our findings.”
The researchers included in the analysis 17 trials with a little over 42,000 participants (mean age 64.4 years, 65 percent male) that had follow-ups ranging from four weeks to 3.5 years. Compared with placebo, any single antiplatelet agent was associated with a significant reduction in recurrence of any stroke and ischemic stroke, but not for the composite outcome of any stroke, myocardial infarction, or death. When other antiplatelet agents (ticlopidine, cilostazol, and dipyridamole) were compared with aspirin, there was no consistent reduction in stroke recurrence. Dual antiplatelet therapy did not confer clear benefit over monotherapy.
Dr. Shoamanesh said the heterogeneous manner by which lacunar stroke was defined among the trials limits the findings. For instance, only one study, the SPS3 trial, used both strict clinical criteria and MRI verification of the qualifying infarct. Moreover, he added, there was insufficient data to assess specific dual antiplatelet therapy regimens or particular outcomes, such as all-cause mortality, in isolation.
“Lastly, our analysis is unable to account for possible differences in treatment effects between the acute or semiacute phase after stroke and the chronic phase,” Dr. Shoamanesh said. “Accordingly, there may still exist a short therapeutic window in the early phases following lacunar stroke where patients derive net benefit from dual antiplatelet therapy.”n