Saturday, June 29, 2013

Aspirin and plavix together: dual antiplatelet therapy for early treatment of minor stroke or high risk TIA

This recently came out in NEJM and everyone's talking about it:

In a randomized, double-blind, placebo-controlled trial conducted at 114 centers in China, we randomly assigned 5170 patients within 24 hours after the onset of minor ischemic stroke or high-risk TIA to combination therapy with clopidogrel and aspirin (clopidogrel at an initial dose of 300 mg, followed by 75 mg per day for 90 days, plus aspirin at a dose of 75 mg per day for the first 21 days) or to placebo plus aspirin (75 mg per day for 90 days). All participants received open-label aspirin at a clinician-determined dose of 75 to 300 mg on day 1...

Stroke occurred in 8.2% of patients in the clopidogrel–aspirin group, as compared with 11.7% of those in the aspirin group (hazard ratio, 0.68; 95% confidence interval, 0.57 to 0.81; P less than 0.001). Moderate or severe hemorrhage occurred in seven patients (0.3%) in the clopidogrel–aspirin group and in eight (0.3%) in the aspirin group (P=0.73); the rate of hemorrhagic stroke was 0.3% in each group.

Among patients with TIA or minor stroke who can be treated within 24 hours after the onset of symptoms, the combination of clopidogrel and aspirin is superior to aspirin alone for reducing the risk of stroke in the first 90 days and does not increase the risk of hemorrhage.

Here's more from Medpage Today.

Some key points:

Prior studies failed to show benefits of dual antiplatelet therapy but they looked at different patient populations (denser and more catastrophic strokes) and had different designs (later treatment).

This study (CHANCE) looked at a more narrowly defined population. It also treated patients earlier (within 24 hours with nearly half within 12 hours). That is important because the event rate was higher early on, particularly in the first two days.

Patient selection was based on the NIH stroke scale for stroke patients (had to be 3 or less) and the ABCD score for TIA patients (had to be 4 or above). Other important exclusions are described in the body of the paper which is available as free full text at the link above.

It is uncertain how well the conclusions of this study, based on a Chinese population (with different risk factors and possibly different genetically programmed responses to Plavix), apply to patients in the US, where a similar trial is getting underway.

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