Background: Good collaterals in acute ischemic stroke (AIS) correlate with smaller infarct size, improved outcome, and better recanalization rates after revascularisation treatments. Given that the variables determining collateral circulation are poorly understood, we aimed to identify predictors of good collaterals in a large series of AIS with middle cerebral artery (MCA) occlusion.
Methods: In the Acute STroke Registry and Analysis of Lausanne (ASTRAL) from 2003 to 2016, we identified all AIS with MCA occlusion (M1 or proximal M2) on CT angiography (CTA) performed within 24 hours. Collaterals were graded from 0 (absent) to 3 (100% or more) and classified as good (grades 2 and 3) or poor. We correlated collateral status with various clinical, metabolic and radiological variables in a univariate, then multivariate regression analyses (MVA).
Results: Of the 2’027 patients with AIS involving the MCA and good quality CTA during the study period, 857 met the inclusion criteria. Median age was 72.3±20.5 years, 48.4% were females, and median admission NIHSS was 16±9. Younger age (OR=0.99, confidence interval (CI) 0.98-0.99) and lower NIHSS on admission (OR=0.92, CI=0.90-0.94) were significantly associated with good collaterals. Hyperglycemia (OR=0.94, CI=0.88-0.99) and higher creatininemia (OR=0.99, CI=0.99-1) correlated with poor collaterals. The distribution of vascular risk factors was similar. Radiologically, good collateral status was predicted by higher ASPECTS score (OR=1.31, CI=1.24-1.40), absence of a hyperdense MCA sign (OR=0.60, CI=0.46-0.79), lower clot burden (OR=1.18, CI=1.12-1.24) and absence of proximal intracranial arterial pathology (OR=0.44, CI=0.33-0.58). MVA results will be presented.
Conclusion: Good collaterals are associated with lower age and lower NIHSS, whereas high blood glucose and creatinine values predicted poor collaterals. On neuroimaging, minor early ischemic changes, lower clot burden and distal site of vascular occlusion correlated with good collaterals. These data may predict stroke outcome in certain patients, explain futile recanalisation, and help select patients for late or aggressive recanalisation treatments independently of time windows.