Metabolic syndrome and resistance to IV thrombolysis in middle cerebral artery ischemic stroke

Objective: The metabolic syndrome (MetS) is a cluster of vascular risk factors associated with a prothrombotic state. We aimed to evaluate the impact of MetS on the response to systemic tPA treatment in patients with acute middle cerebral artery (MCA) ischemic stroke. Methods: We studied 100 consecutive patients with ischemic stroke with MCA occlusions on prebolus transcranial Doppler (TCD) examination treated with tPA following SITS-MOST criteria. MetS was diagnosed following AHA/NHLBI-2005 criteria. Resistance to thrombolysis was defined as the absence of TCD-assessed complete MCA recanalization 24 hours after tPA infusion. Infarct volume was measured on CT scans. Long-term clinical outcome was evaluated by the modified Rankin scale (mRS) score at day 90. Results: Fifty-eight (58%) patients fulfilled MetS criteria. Median prebolus NIH Stroke Scale score was 17. Forty (42%) patients showed resistance to clot dissolution, and 53 (53%) had poor clinical outcomes (mRS > 2). A multivariable-adjusted logistic regression model identified MetS as independently associated with resistance to thrombolysis (OR 4.7, 95% CI [1.7-13.6], p = 0.004). In the whole sample, MetS was associated with mRS > 2 (OR 2.4 [1.1-5.4], p = 0.03), although this association was no longer significant after multivariable adjustment. However, in patients with atherothrombotic stroke, MetS emerged as an independent predictor of poor long-term outcome (adjusted OR 13.9 [1.3-148.7], p = 0.02). Conclusion: In our series, the metabolic syndrome was associated with a poor response to thrombolysis in patients with acute middle cerebral artery occlusions, as reflected by a higher resistance to clot dissolution.