Platelet count and clinical outcomes among ischemic stroke patients with endovascular thrombectomy in DIRECT-MT

OBJECTIVES: The prognostic role of baseline platelet count (PLT) in acute ischemic stroke patients with large vessel occlusion undergoing endovascular thrombectomy is unclear. Whether PLT modifies alteplase treatment effect on clinical outcome in those patients is also uncertain. METHODS: We derived data from a multicenter randomized clinical trial (DIRECT-MT) comparing intravenous alteplase before endovascular treatment vs. endovascular treatment only. The 654 patients with available PLT data were included. Primary outcome was the ordinal modified Rankin Scale (mRS) score evaluated at 90 days. We also assessed various secondary and safety outcomes. RESULTS: After adjusting for confounding factors, patients in the top tertile of PLT had a significantly lower risk of a worse shift in the distribution of mRS score (Odds Ratio: 0.671, 95% Confidence Interval: 0.473-0.953, p for trend=0.025), major disability and death (Odds Ratio: 0.617, 95% Confidence Interval: 0.393-0.97, p for trend=0.037) as well as death (Odds Ratio: 0.544, 95% Confidence Interval: 0.313-0.947, p for trend=0.031), respectively, compared with the bottom one. Among patients in the bottom tertile of PLT, combination therapy was associated with a better imaging outcome of eTICI score of 2b, 2c or 3 on final angiogram (Odds Ratio: 3.23, 95% Confidence Interval: 1.49-7.002) with a marginally significant interaction effect. CONCLUSIONS: Participants with higher baseline PLT had a decreased risk of poor functional outcomes. Low baseline PLT modified alteplase treatment effect on the eTICI score on final angiogram. Combination therapy was beneficial for patients with low baseline PLT to have a better reperfusion status.