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| Dean Reinke Deans’ Stroke Musing |
See what your doctor thinks about this research, No self-diagnosis. Aspirin, Plavix Not Good Stroke Prevention Combo.
Combining clopidogrel (Plavix) with aspirin did not prevent recurrent stroke deep in the brain, and even increased the risk of bleeding and death, according to a double-blind, randomized trial that was halted.
Patients receiving the dual antiplatelet therapy had a 2.1% risk of major bleeding -- double the 1.1% risk of those on aspirin plus placebo (P<0.001), Oscar Benavente, MD, from the University of British Columbia in Vancouver, and colleagues found.
Similarly, the annual risk of all-cause death was greater with the combined therapy: 2.1% for aspirin plus clopidogrel compared with 1.4% for aspirin plus placebo (P=0.005), Benavente reported here at the American Stroke Association's International Stroke Conference.
The addition of clopidogrel to aspirin resulted in a nonsignificant 8% reduction in the primary outcome of ischemic or hemorrhagic stroke. Considering ischemic stroke alone, the combination therapy conferred a nonsignificant 15% reduction in the risk, but increased the risk of hemorrhagic stroke by a nonsignificant 7%.
The addition of clopidogrel to aspirin, however more than doubled the risk of hemorrhages outside the central nervous system (HR 2.2, 95% CI 1.5 to 3.1, P<0.001), Benavente reported.
For all-cause mortality, only the category of "possible vascular events" reached significance; whereas cerebral, noncerebral, and nonvascular events did not reach significance for the combination therapy.
Because of these preliminary results from the Secondary Prevention of Small Subcortical Strokes Trial (SPS3) and the input from the data monitoring board, the researchers ended the anticlotting part of the study in August 2011.
A futility analysis showed that, given the current observed data, there was only a small probability of showing a benefit in favor of combination therapy over aspirin alone if this part of the trial continued to the planned end.
"These interim results do not support the use of combination clopidogrel plus aspirin for secondary stroke prevention in patients with small subcortical strokes," Benavente said.
The American Heart Association/American Stroke Association guidelines for preventing recurrent strokes recommend monotherapy, such as aspirin or clopidogrel, but not the combination of the two.
Lacunar strokes are a common condition of vascular disease, responsible for more than 25% of all brain infarcts, and with a particularly high prevalence (70%) in minorities. Benavente said that various treatments have not been compared specifically in patients with subcortical strokes, the most common cause of vascular dementia.
The SPS3 trial is the first large-scale study of such patients. The researchers enrolled 3,020 participants from 81 clinical sites and eight countries, and followed them for up to 3.5 years. The randomization took place from March 2003 to April 2011.
In other trials, the combination of clopidogrel and aspirin have shown no difference in the rate of death, but that might have been confounded by vascular death, Benavente said. For this trial, the researchers wanted to better understand the reasons for mortality.
Inclusion criteria included having had an MRI-verified lacunar stroke within 180 days. Patients with cortical stroke, cardioembolic disease, or carotid stenosis were excluded from the trial.
Baseline characteristics were similar between both arms. The strokes were fairly mild, with more than two-thirds of the patients in each arm having a mean Rankin score between 0 and 1. The overall mean Mini Mental State Examination score in both arms was 28.
Three-quarters of the patients had hypertension and nearly half had hyperlipidemia; 10% had a prior stroke and 6% had a prior transient ischemic event. Clinical syndromes were similar in each arm.
Despite the results in this trial, the door is still open for studying new anti-clotting agents in subcortical strokes, Benavente said.
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