Vertebral Artery Stump Research Articles

A case of suspected vertebral artery stump syndrome assessed by CT angiography

A 55-year-old man developed ischemic stroke in the bilateral cerebellar hemispheres and bilateral occipital lobes. He was admitted to our hospital 17 months later with recurrent ischemic stroke in the posterior circulation. The left vertebral artery (VA) was occluded on brain magnetic resonance angiography but was visualized with a delay on continuous three-phase CT angiography (CTA). Conventional angiography confirmed a to-and-fro blood flow pattern at the distal end of the left VA, therefore the patient was diagnosed with VA stump syndrome (VASS). VASS is a recurrent posterior circulation ischemic stroke caused by thrombi in an occluded unilateral VA. VASS should be suspected in patients with unilateral VA occlusion and repeated posterior-circulation ischemic stroke. The diagnostic criteria for VASS include confirmation of VA occlusion and the presence of an antegrade flow component at the distal end. In this case, the presence of collateral circulation in the VA was suspected based on CTA findings, leading to the diagnosis of VASS. It was thus suggested that devising the imaging method of CTA may help diagnose VASS.

Ruptured vertebrobasilar junction aneurysm supplied by reversed flow from the anterior spinal artery: Illustrative case report.

In patients with vertebral artery (VA) occlusion, spontaneous flow reversal may occur in the anterior spinal artery (ASA) as a source of compensatory supply to the posterior circulation. Turbulent flow and increased flux through these small arteries may predispose to luminal damage and intracranial aneurysm formation. We report a novel case of a ruptured ASA-VA junction aneurysm in a patient with chronic bilateral VA occlusion, successfully treated with endovascular embolization. A 62-year-old female with uncontrolled hypertension presented with acute-onset headache, emesis, neck stiffness, and decreased level of consciousness. Head computed tomography demonstrated diffuse cisternal subarachnoid hemorrhage with intraventricular extension and ventriculomegaly. Computed tomography angiography showed left VA atresia and chronic right VA occlusion just distal to the posterior inferior cerebellar artery origin, as well as a complex, bilobed aneurysm at the ASA-VA junction. Angiography demonstrated flow reversal from the ASA into the distal stump of the occluded right VA, which in turn filled the aneurysm. Of note, the patient's posterior circulation was predominantly supplied by the dilated ASA, and associated collaterals from ASA and right VA stump. The aneurysm was accessed and embolized using superselective microcatheterization over a soft microguidewire through the right cervical VA perforators supplying retrograde flow into and through the ASA. ASA-VA aneurysms are exceedingly rare, and generally associated with atypical flow dynamics. Dynamic treatment strategies may be needed, especially in the setting of subarachnoid hemorrhage.

Vertebral artery stump syndrome in acute ischemic stroke

Although the carotid artery stump as an embolic source for ischemic stroke has been well described, there have been few systematic reports of a similar syndrome in the posterior circulation (PC) after vertebral artery (VA) origin occlusion. The aim of this study was to identify the incidence and characteristics of acute ischemic stroke with VA stump syndrome. Of 3463 consecutive patients who were admitted within 7days after onset, 865 patients with acute ischemic stroke in the PC were enrolled. The diagnostic criteria of VA stump syndrome included: (1) acute ischemic stroke in the posterior circulation; (2) the VA origin occlusion identified on MRA, duplex ultrasound, CT angiography, and/or conventional angiography; (3) presence of distal antegrade flow in the ipsilateral VA; and (4) absence of other causes of ischemic stroke. Of the 865 patients with PC stroke, 12 (1.4%) were diagnosed as having VA stump syndrome. The ischemic lesions included the cerebellum in all patients. Nine patients had multiple ischemic lesions in the brain stem, thalamus, or posterior lobe other than cerebellum. On duplex ultrasound, a to-and-fro flow pattern was observed in the culprit VA in 10 patients. Three patients had recurrences of ischemic stroke in the PC during the acute phase. VA stump syndrome was not a rare mechanism of PC stroke, and there was a high rate of stroke recurrence during the acute phase. Vascular assessment by a multimodality approach can be used to promptly detect VA stump syndrome.

Intraoperative Hemodynamic Measurements of the Vertebral Artery and Common Carotid Artery

The hemodynamics in the vertebrobasilar artery (VBA) system were investigated in patients with vertebrobasilar insufficiency (VBI). Vertebral artery (VA) stump pressure and blood flows in the VA and common carotid artery (CCA) were intraoperatively measured in 45 patients who underwent surgical correction of the first segment of the VA (V1) for angiographic tortuosity, kinking, and/or stenosis manifesting as symptomatic VBI. The effects of changes in the systemic arterial blood pressure (SABP) induced by trimethaphan, phenylephrine, and cervical epidural anesthesia were also investigated. The VA stump pressure was 79.3 +/- 13.6 (mean +/- SD) mmHg and the ratio of the VA stump pressure to the SABP was 0.87 +/- 0.08. The baseline values were SABP 90.5 +/- 10.1 mmHg, VA blood flow 53.4 +/- 33.0 ml/min, and CCA blood flow 204.3 +/- 50.3 ml/min. During changes in the SABP, autoregulation of the blood flow in the VA appeared tighter than in the CCA. During cervical epidural anesthesia, blood flows in both the VA and CCA were significantly reduced in response to SABP reduction. This study demonstrated that the VBA system maintains excellent autoregulation with good collateral flows and cervical sympathetic nerve function. However, this autoregulatory capacity may be overwhelmed by unexpected occlusion of the VA due to postural changes associated with tortuosity, kinking, and/or stenosis of the V1 segment.