Hemodynamic Features of Symptomatic Vertebrobasilar Disease
Authors: Amin-Hanjani Sepideh , Du Xinjian , Rose-Finnell Linda , Pandey Dilip K. , Richardson DeJuran , Thulborn Keith R. , Elkind Mitchell S.V. , Zipfel Gregory J. , Liebeskind David S. , Silver Frank L. , Kasner Scott E. , Aletich Victor A. , Caplan Louis R. , Derdeyn Colin P. , Gorelick Philip B. , Charbel Fady T. ,   VERiTAS Study Group, Xie Hui , Flannery Michael P. , Ganin Hagai , Ruland Sean , Grysiewicz Rebecca , Khaja Aslam , Pedelty Laura , Testai Fernando , Ong Archie , Epstein Noam , Muqtadar Hurmina , Watson Karriem , Mlinarevich Nada , Hillmann Maureen , Hirsch Joy , Dashnaw Stephen , Meyers Philip M. , Willey Josh Z. , McNeill-Simaan Edwina , Perez Veronica , Canaan Alberto , Paulino-Hernandez Wayna , Vo Katie , Foster Glenn , Ford Andria , Nassief Abdullah , Bradley Abbie , Serna-Northway Jannie , Kraus Kristi , Shiwani Lina , Hantler Nancy , Alger Jeffrey , Godinez Sergio , Saver Jeffrey L. , Ali Latisha , Kim Doojin , Tenser Matthew , Froehler Michael , Raychev Radoslav , Song Sarah , Ovbiagele Bruce , Abcede Hermelinda , Adamczyk Peter , Rao Neal , Yallapragada Anil , Modir Royya , Hinman Jason , Tansy Aaron , Calderon-Arnulphi Mateo , Sheth Sunil , Noorian Alireza , Ng Kwan , Liang Conrad , Gadhia Jignesh , Smith Hannah , Avila Gilda , Avelar Johanna , Mikulis David , Fierstra Jorn , Hlasny Eugen , Casaubon Leanne K. , Vergouwen Mervyn , del Campo J.C. Martin , Jaigobin Cheryl S. , Astorga Cherissa , Kalman Libby , Kramer Jeffrey , Vaughan Susan , Owens Laura , Kissela Brett , Turan Tanya N. , Jacobs Tom P. , Janis Scott 
Published: May 2015

Background and Purpose—
Atherosclerotic vertebrobasilar disease is an important cause of posterior circulation stroke. To examine the role of hemodynamic compromise, a prospective multicenter study, Vertebrobasilar Flow Evaluation and Risk of Transient Ischemic Attack and Stroke (VERiTAS), was conducted. Here, we report clinical features and vessel flow measurements from the study cohort.

Methods—
Patients with recent vertebrobasilar transient ischemic attack or stroke and ≥50% atherosclerotic stenosis or occlusion in vertebral or basilar arteries (BA) were enrolled. Large-vessel flow in the vertebrobasilar territory was assessed using quantitative MRA.

Results—

The cohort (n=72; 44% women) had a mean age of 65.6 years; 72% presented with ischemic stroke. Hypertension (93%) and hyperlipidemia (81%) were the most prevalent vascular risk factors. BA flows correlated negatively with percentage stenosis in the affected vessel and positively to the minimal diameter at the stenosis site (
P
<0.01). A relative threshold effect was evident, with flows dropping most significantly with ≥80% stenosis/occlusion (
P
<0.05). Tandem disease involving the BA and either/both vertebral arteries had the greatest negative impact on immediate downstream flow in the BA (43 mL/min versus 71 mL/min;
P
=0.01). Distal flow status assessment, based on an algorithm incorporating collateral flow by examining distal vessels (BA and posterior cerebral arteries), correlated neither with multifocality of disease nor with severity of the maximal stenosis.

Conclusions—
Flow in stenotic posterior circulation vessels correlates with residual diameter and drops significantly with tandem disease. However, distal flow status, incorporating collateral capacity, is not well predicted by the severity or location of the disease.