In patients receiving intravenous tissue plasminogen activator for ischemic stroke, antiplatelet therapy before stroke was associated with a slightly increased risk of symptomatic intracranial hemorrhage. However, this relatively small increased risk did not translate into higher mortality rates, and previous antiplatelet therapy instead appeared to be associated with favorable functional outcomes, according to research published in JAMA Neurology.
In one of the largest studies of its kind, Ying Xian, MD, PhD, from Duke Clinical Research Institute in Durham, North Carolina and colleagues analyzed data from the American Heart Association and American Stroke Association “Get With the Guidelines–Stroke” registry for 85,072 adult patients with ischemic stroke who received intravenous tissue plasminogen activator (IV tPA) from 2009 to 2015.
Of the 85,072 patients, 38,844 (45.7%) were using antiplatelet therapy before admission to the hospital, and 46,228 (54.3%) were not. The researchers defined “antiplatelet therapy” as documentation of a patient taking an antiplatelet medication within 7 days before arriving at the hospital, and categorized antiplatelet therapy into four groups: (1) aspirin alone, (2) a combination of aspirin and dipyridamole, (3) clopidogrel alone, and (4) dual antiplatelet therapy with aspirin and clopidogrel.
Patients receiving antiplatelet therapy before admission were older (median [25th -75th percentile] age, 76 [65-84] vs. 68 [56-80] years), had higher rates of cardiovascular risk factors, and were more likely to receive antihypertensives or medications to lower cholesterol or glucose levels, but were less likely to receive anticoagulants before hospital admission (P < .001 for all).
Overall, 3,647 patients (4.3%) developed a symptomatic intracranial hemorrhage (sICH) after IV tPA administration. Patients receiving antiplatelet therapy had a higher crude rate of sICH (5%) than those who were not receiving antiplatelet therapy before the stroke (3.7%). After risk adjustment, antiplatelet therapy was independently associated with higher odds of sICH (adjusted OR[AOR], 1.18; 95% CI, 1.10-1.28), although the absolute excess risk was small (absolute difference +0.68% [95% CI, 0.36%-1.01%]; NNH, 147).
Treatment with aspirin alone followed by aspirin-clopidogrel dual antiplatelet therapy was associated with higher increased risk for sICH compared with no antiplatelet treatments.
Despite higher bleeding rates, prior antiplatelet therapy was not associated with increased mortality rates. On the contrary, patients who received antiplatelet therapy before treatment for stroke had greater odds of being able to walk independently after discharge.
While antiplatelet therapy prior to IV tPA stroke treatment was associated with a slightly increased risk for sICH, that risk did not translate into higher mortality rates and was actually associated with favorable functional outcomes, leading the researchers to conclude that “the overall benefits of thrombolytic therapy may outweigh the risks in eligible patients with ischemic stroke receiving antiplatelet therapy before stroke onset.”
- Xian Y, Federspiel JJ, Grau-Sepulveda M, et al. Risks and Benefits Associated With Prestroke Antiplatelet Therapy Among Patients With Acute Ischemic Stroke Treated With Intravenous Tissue Plasminogen Activator. JAMA Neurol. 2015; doi:10.1001/jamaneurol.2015.3106.