White matter hyperintensity load on stroke recurrence and mortality at 1 year after ischemic stroke

Abstract

Objective To define the role and risks associated with white matter hyperintensity (WMH) load in a stroke population with respect to recurrent stroke and mortality after ischemic stroke. Methods A total of 7,101 patients at a network of university hospitals presenting with ischemic strokes were followed up for 1 year. Multivariable Cox proportional hazards model and competing risk analysis were used to examine the independent association between quartiles of WMH load and stroke recurrence and mortality at 1 year. Results Overall recurrent stroke risk at 1 year was 6.7%/y, divided between 5.6%/y for recurrent ischemic and 0.5%/y for recurrent hemorrhagic strokes. There was a stronger association between WMH volume and recurrent hemorrhagic stroke by quartile (hazard ratio [HR] 7.32, 14.12, and 33.52, respectively) than for ischemic recurrence (HR 1.03, 1.37, and 1.61, respectively), but the absolute incidence of ischemic recurrence by quartile was higher (3.8%/y, 4.5%/y, 6.3%/y, and 8.2%/y by quartiles) vs hemorrhagic recurrence (0.1%/y, 0.4%/y, 0.6%/y, and 1.3%/y). All-cause mortality (10.5%) showed a marked association with WMH volume (HR 1.06, 1.46, and 1.60), but this was attributable to nonvascular rather than vascular causes. Conclusions There is an association between WMH volume load and stroke recurrence, and this association is stronger for hemorrhagic than for ischemic stroke, although the absolute risk of ischemic recurrence remains higher. These data should be helpful to practitioners seeking to find the optimal preventive/treatment regimen for poststroke patients and to individualize risk-benefit ratios.