Differential Benefit of Collaterals for Stroke Patients Treated with Thrombolysis or Supportive Care : A Propensity Score Matched Analysis.

Leptomeningeal collaterals can slow down infarction growth; however, despite good collaterals in the DAWN and DEFUSE 3 trials, outcomes were devastating if reperfusion was not attempted. The aim of this study was to compare the influence of collaterals on morphological and functional outcome in patients with acute middle cerebral artery (MCA) stroke undergoing intravenous thrombolysis (IVT) vs. supportive care (non-IVT). Out of 1639 consecutive patients examined with multiparametric computed tomography (CT) for suspected ischemic stroke, all patients with confirmed MCA stroke who did not undergo endovascular thrombectomy were selected. Propensity score matching (PSM) was used to match IVT and non-IVT treated patients for potential confounders including age, sex, National Institutes of Health Stroke Scale (NIHSS) score on admission, Alberta Stroke Program Early CT Score (ASPECTS), and occlusion site. Regression analysis after PSM was performed to identify independent associations. After PSM, 90 IVT patients were matched with 90 non-IVT patients. In multivariable regression analysis, a high regional leptomeningeal collateral (rLMC) score was independently associated with lower final infarction volume (FIV) in the IVT group (b = −0.472, p < 0.001) but not in the non-IVT group (b = −0.116, p = 0.327). The trichotomized rLMC scores predicted functional outcome in IVT treated patients (adjusted odds ratio, aOR = 4.57, 95% confidence interval, CI, 1.03–20.32, p = 0.046) but showed no independent association with outcome in the non-IVT group (aOR = 0.69, 95% CI 0.07–6.80, p = 0.753). Good collaterals favored smaller FIV and good functional outcome in IVT treated patients but not in non-IVT treated patients. Good collateral flow may have limited prognostic value if IVT is not administered to attempt reperfusion