Abstract 20: Higher Stroke Risk With Lower Blood Pressure in Hemodynamic Vertebrobasilar Disease: Analysis From the Prospective Multicenter VERiTAS Study

Abstract

Introduction: Despite theoretical concerns regarding hypoperfusion in patients with large artery occlusive disease, strict blood pressure (BP) control has become adopted as a safe strategy for stroke risk reduction. We examined the relationship between BP control, flow, and risk of subsequent stroke in the prospective Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS) Study. Hypothesis: Strict BP control may be less efficacious and safe in flow compromised patients with symptomatic vertebrobasilar (VB) disease. Methods: VERiTAS enrolled patients with recent VB TIA or stroke and ≥50% atherosclerotic stenosis or occlusion of vertebral or basilar arteries. Hemodynamic status using large vessel flow in the VB territory was designated as low or normal flow using quantitative MRA. Patients underwent standard medical management and follow-up for primary outcome event of VB territory stroke. Mean SBP during follow-up (<140 vs. ≥140 mm Hg) and flow status were examined relative to subsequent stroke risk using Cox proportional hazards analysis. Results: The 72 enrolled subjects had an average of 3.8±1.2 BP recordings over the 20 ±8 months of follow-up; 40 (56%) had mean SBP of <140 mm Hg. The BP groups were largely comparable for baseline demographics, risk factors, and stenosis severity. There was a trend to a higher risk of subsequent stroke in patients with SBP <140 mm Hg (20% vs. 6.2%, p=0.17). As shown in the Figure, comparing subgroups stratified by SBP and hemodynamic status revealed that patients with both low flow and SBP <140 mm Hg (n=10) had a higher risk of subsequent stroke with HR 4.5 (CI 1.3-16.0, p=0.02) compared to the other subgroups combined. Conclusion: Among a subgroup of patients with VB disease and low flow, strict BP control (SBP <140) appears to increase the risk of recurrent stroke. This finding within a modest sized cohort supports the strategy of hemodynamic assessment to inform decision making regarding BP management.