Clopidogrel, dipyridamole yield similar embolyzation reduction in patients taking aspirin

**King A. Stroke. 2011;42:650-655.**

Issue: April 2011

Dipyridamole and clopidogrel, when combined with aspirin, have similar efficacies in early secondary prevention of stroke in patients with acute symptomatic large artery disease, researchers have found.

Sixty patients, all on aspirin and who presented with recent symptomatic carotid stenosis to an acute stroke unit or rapid access transient ischemic attack clinic in the same hospital, were randomly assigned clopidogrel (Plavix, Sanofi Aventis) or dipyridamole (Persantine, Boehringer Ingelheim); there were 30 patients in each arm. Inclusion criteria included carotid stenosis of at least 50%, with symptoms of TIA or stroke within the past month, and those aged 18 years and older. Excluded were patients with prosthetic heart valves; those taking antithrombotic medication other than aspirin and/or low-dose prophylactic subcutaneous heparin; contraindication to clopidogrel or dipyridamole; those scheduled to have carotid endarterectomy within the next 48 hours; and pregnant or lactating women.

Ambulatory transcranial Doppler and platelet aggregometry were performed at baseline and at 48 hours. The primary endpoint of change in embolic frequency was the same for each group (P=.36). Embolic signals at baseline did not reduce embolic signal frequency: dipyridamole (75.5; SD=17.7%); clopidogrel (77.5; SD=20.5%; P=.77). Baseline platelet aggregation was the same in both arms, but at 48 hours, adenosine 5’-diphosphate aggregation rate (but not collagen) was lower with clopidogrel (P<.001).

“Our results suggest these two treatment regimens will have similar efficacy in early secondary prevention of large artery stroke, although to ensure the reduction in [embolic signals] can be translated into clinical events, it now needs testing in a large phase 3 trial with the endpoint of stroke,” the researchers wrote.

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