Stroke risk declined by a third in people who took a combination of antiplatelet drugs after having a transient ischemic attack (TIA) or minor stroke, a large randomized trial showed.
The combination of clopidogrel (Plavix) and aspirin led to a 3.5% absolute difference in 90-day stroke rate compared with individuals who took only aspirin (8.2% versus 11.7%).
Patients treated with the combination had a lower stroke risk with no increased risk of moderate or severe bleeding. The pattern of benefit emphasized the importance of prompt treatment, Yongjun Wang, MD, of Beijing Tiantan Hospital in China, and co-authors reported online in the New England Journal of Medicine.
“The curves for survival free of stroke were particularly steep in the first few days, during which the curves representing the treatment groups diverged dramatically,” the authors said.
“Subsequently, the rates of stroke were similar. This suggests that the requirement for randomization within 24 hours after the onset of symptoms, with nearly half the patients enrolled within 12 hours (and treated shortly thereafter), was important.”
Although moderate or more severe bleeding did not differ between groups, combination therapy was associated with an overall trend toward more bleeding.
Preliminary results of the trial were first reported in February at the International Stroke Conference in Honolulu.
The trial results are impressive, but several caveats apply to their interpretation, particularly their limited applicability, according to the author of an editorial in the same issue.
“The implication of this trial is that Chinese patients with acute TIA or minor ischemic stroke (onset within the previous 24 hours) who are at high risk for recurrence should be regarded as a medical emergency,” wrote Graeme J. Hankey, MD, of the University of Western Australia in Perth.
A transient ischaemic attack (TIA) or ‘mini stroke’ is caused by a temporary disruption in the blood supply to part of the brain.
The disruption in blood supply results in a lack of oxygen to the brain. This can cause symptoms similar to those of a stroke, such as speech and visual disturbance and numbness or weakness in the arms and legs.
However, a TIA does not last as long a stroke. The effects only last for a few minutes and are usually fully resolved within 24 hours.
The main signs and symptoms of a TIA can be identified by remembering the word F.A.S.T., which stands for Face-Arms-Speech-Time.
Face – the face may have fallen on one side, the person may be unable to smile, or their mouth or eye may have dropped
Arms – the person may not be able to raise both their arms and keep them there due to weakness or numbness in their arms
Speech – the person may have slurred speech
Time – if any of these signs or symptoms are present, it is time to dial 999 immediately
TIA and minor stroke confer a 10% to 20% risk of major stroke within 3 months, most of which occur within 2 days of the TIA or minor stroke. Antiplatelet therapy has a well established role in secondary stroke prevention, but only aspirin has been evaluated in acute stroke, wherein it demonstrated only a modest effect, the authors noted in their introduction.
Several studies have found no benefit of dual antiplatelet therapy for secondary prevention after stroke. However, the studies did not examine the impact of combination therapy in the early, high-risk period after stroke, they included patients with moderately severe strokes, and they had few patients with TIA.
Small pilot studies have suggested a benefit of combination therapy in patients with minor stroke or TIA and showed the benefit was associated with minimal safety risk.
To examine dual antiplatelet therapy on a large scale, the investigators enrolled patients at 114 centers in China within 24 hours of minor stroke or TIA into an intervention study called CHANCE (Clopidiogrel in High-Risk Patients with Acute Non-Disabling Cerebrovascular Events).
Preventing a TIA
TIAs often occur without warning. If you have a TIA, it is a sign another one may follow and further TIAs can have more serious effects or develop into a full, life-threatening stroke.
Regardless of whether or not you have had a TIA or stroke in the past, there are a number of ways you can lower your risk of having either in the future. These include:
maintaining a healthy weight
taking regular exercise
limiting your alcohol consumption
Patients were randomized to the combination of clopidogrel and aspirin or to placebo and aspirin. Patients in the clopidogrel group received both agents for the first 21 days, followed by clopidogrel alone to day 90. Patients in the placebo group received aspirin for 90 days.
The protocol excluded patients who sought treatment beyond the 24-hour time window, who had moderate or severe strokes, or who had intracerebral hemorrhage.
Stroke risk declined by a third in people who took a combination of antiplatelet drugs after having a transient ischemic attack or minor stroke.
Note that although moderate or more severe bleeding did not differ between groups, combination therapy was associated with an overall trend toward more bleeding.