Natural History of Hemodynamics in Vertebrobasilar Disease

Abstract

Background and Purpose: The role of regional hypoperfusion as a contributor to stroke risk in atherosclerotic vertebrobasilar disease has recently been confirmed by the observational VERiTAS (Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke) Study. We examined the stability of hemodynamic status over time and its relationship to stroke risk in patients from this prospective cohort. Methods: VERiTAS enrolled patients with recently symptomatic ≥50% atherosclerotic stenosis/occlusion of vertebral and/or basilar arteries. Large vessel flow in the vertebrobasilar territory was assessed using quantitative magnetic resonance angiography, and patients were designated as low or normal flow based on distal territory regional flow, incorporating collateral capacity. Patients underwent standard medical management and follow-up for primary outcome event of vertebrobasilar territory stroke. Quantitative magnetic resonance angiography imaging was repeated at 6, 12, and 24 months. Flow status over time was examined relative to baseline and relative to subsequent stroke risk using a cause-specific proportional hazard model, with flow status treated as a time-varying covariate. Mean blood pressure was examined to assess for association with changes in flow status. Results: Over 19±8 months of follow-up, 132 follow-up quantitative magnetic resonance angiography studies were performed in 58 of the 72 enrolled patients. Of the13 patients with serial imaging who had low flow at baseline, 7 (54%) had improvement to normal flow at the last follow-up. Of the 45 patients who had normal flow at baseline, 3 (7%) converted to low flow at the last follow-up. The mean blood pressure did not differ in patients with or without changes in flow status. The time-varying flow status remained a strong predictor of subsequent stroke (hazard ratio,10.3 [95% CI, 2.2–48.7]). Conclusions: There is potential both for improvement and worsening of hemodynamics in patients with atherosclerotic vertebrobasilar disease. Flow status, both at baseline and over time, is a risk factor for subsequent stroke, thus serving as an important prognostic marker. REGISTRATION: URL: https://clinicaltrials.gov . Unique identifier: NCT00590980.

Association Between the Degree of Vertebrobasilar Stenosis, Location, Infarction Pattern and QMRA Flow State

“…The initial inclusion criteria for the VERiTAS study included patients with unilateral high-grade vertebral stenosis, however, this was later changed to an exclusion criterion after an early interim analysis revealed a disproportionate number of normal distal-flow states (8:1 ratio) with isolated unilateral disease. 12 Our findings support this low rate of low distal-flow as roughly one-eighth of our patients with unilateral vertebral disease had low distal-flow states. A VERiTAS analysis, comprised of <10% of the study population with unilateral vertebral disease, found no significant difference between vessel location, severity of disease, and distal-flow status.…”

“…[8][9][10] Despite the complexity of stroke mechanisms, randomized treatment trials have focused primarily on luminal stenosis as entry criteria, [2][3][4][5] discounting the potential role of hemodynamics, plaque morphology, and potential for embolization. Although luminal stenosis correlates strongly with single-vessel hemodynamics 11,12 and recurrent stroke risk, 7 its influence on regional and downstream blood flow is greatly influenced by collateral status and anatomical variability. Attempts to account for these differences in the posterior circulation have been introduced by VERiTAS investigators by devising an algorithm focused on distal-flow status measured on quantitative magnetic resonance angiography (QMRA), derived from flow in the basilar and both non-fetal posterior cerebral arteries.…”

New Insight Into Neutrophils: A Potential Therapeutic Target for Cerebral Ischemia

“…Sepideh Amin-Hanjan et al studied the hemodynamic stability over time and its association with stroke risk in a prospective cohort study of VERiTAS (Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke). The results showed that the risk of stroke in patients with recently symptomatic vertebrobasilar atherosclerosis disease and posterior circulation hemodynamic injury after one year was five times that in patients without hemodynamic injury (22% vs 4%) (109). Therefore, there is an important correlation between atherosclerosis and ischemic stroke, and neutrophils play an important role in this pathophysiological process.…”

Integrated care for optimizing the management of stroke and associated heart disease: a position paper of the European Society of Cardiology Council on Stroke

“…The stroke pathway is not straightforward as up to 40% of patients get worse after they come into the stroke unit, mostly within the first 24 h. 45 This is referred to as early neurological deterioration, which, if it persists, is termed stroke progression and reflects secondary brain injury. 46 , 47 This fluctuation in patient’s condition can be the result of potentially reversible physiological or neurological factors (brady-/tachycardia, high or low blood glucose, increased metabolic rate in infection) although sometimes they are irreversible (e.g. mass effect, brain stem herniation).…”