Wolcott, Zoe

Introduction: Collateral cerebrovasculature is important for the survival of penumbral tissue in patients with large vessel occlusive (LVO) stroke, and adequate collateralization is associated with favorable outcomes. The presence of cerebral microbleeds (CMB) have been implicated in vessel wall remodeling and impaired vasoreactivity. We investigated whether the presence of deep and/or lobar CMB predicts poor collateral recruitment in patients with LVO stroke who underwent thrombectomy (MT). Methods: We performed a retrospective, single-center study of adults who presented with LVO stroke and had MT between January 2012-June 2020. CT angiography of head prior to MT was used to assess collateral status with poor status defined as ≤50% filling and good status as >50% filling. CMBs were assessed using T2*-weighted gradient echo or susceptibility weighted magnetic resonance images. Location of CMB was further characterized as deep vs. lobar using consensus definitions. Poor stroke outcome was defined as modified Rankin Scale (mRS) ≥3 at 90 days. Multivariable logistic regressions were performed to evaluate the associations between CMB, CMB types (lobar, deep, lobar+deep) and poor collaterals after adjusting for vascular risk factors. Results: Consecutive 151 subjects were included (mean age 68±15 years, 47% women), with a median NIHSS of 18. CMB were identified in 57 subjects (37.4%). Of these, 20.5% had lobar CMB, 5.3% had deep CMB and 11.9% had combined lobar & deep CMB. Patients with CMB had higher odds of having poor collaterals compared to those without CMB (OR 1.56, 95% CI 1.09-2.23, P=0.015). The association of CMB with poor collaterals was strongest in patients with combined lobar & deep CMB (OR 4.78, 95% CI 1.43-15.93, P=0.011), compared with those with exclusively deep CMB (OR 2.78, 95% CI 0.44-17.62, P=0.278) or lobar CMB (OR 0.52, 95% CI 0.19-1.38, P=0.188). Patients with poor collaterals were more likely to have poor outcome compared with those with good collaterals (48.4% vs. 31.0%, P=0.03). Conclusion: Cerebral microbleeds are independently associated with poor collateral recruitment when adjusted for traditional vascular risk factors. Further study is warranted to elucidate the differential effects of CMB types on collateral recruitment.

Background: Treatment of uncontrolled arterial hypertension reduces the risk of cerebral small vessel disease (CSVD) progression, although it is unclear whether this reduction occurs due to blood pressure control or class-specific pleiotropic effects, such as improved beat-to-beat arterial pressure variability with calcium channel blockers. The goal of this study was to investigate the influence of antihypertensive medication class, particularly with calcium channel blocker, on accumulation of white matter hyperintensities (WMH), a radiographic marker of CSVD, within a cohort with well-controlled hypertension. Methods: We completed an observational cohort analysis of the SPRINT-MIND trial (Systolic Blood Pressure Trial Memory and Cognition in Decreased Hypertension), a large randomized controlled trial of participants who completed a baseline and 4-year follow-up brain magnetic resonance image with volumetric WMH data. Antihypertensive medication data were recorded at follow-up visits between the magnetic resonance images. A percentage of follow-up time participants were prescribed each of the 11 classes of antihypertensive was then derived. Progression of CSVD was calculated as the difference in WMH volume between 2 scans and, to address skew, dichotomized into a top tertile of the distribution compared with the remaining. Results: Among 448 individuals, vascular risk profiles were similar across WMH progression subgroups except age (70.1±7.9 versus 65.7±7.3 years; P <0.001) and systolic blood pressure (128.3±11.0 versus 126.2±9.4 mm Hg; P =0.039). Seventy-two (48.3%) of the top tertile cohort and 177 (59.2%) of the remaining cohort were in the intensive blood pressure arm. Those within the top tertile of progression had a mean WMH progression of 4.7±4.3 mL compared with 0.13±1.0 mL ( P <0.001). Use of angiotensin-converting enzyme inhibitors (odds ratio, 0.36 [95% CI, 0.16–0.79]; P =0.011) and dihydropyridine calcium channel blockers (odds ratio, 0.39 [95% CI, 0.19–0.80]; P =0.011) was associated with less WMH progression, although dihydropyridine calcium channel blockers lost significance when WMH was treated as a continuous variable. Conclusions: Among participants of SPRINT-MIND trial, angiotensin-converting enzyme inhibitor was most consistently associated with less WMH progression independent of blood pressure control and age.