Reversed flow in the basilar artery in acute vertebrobasilar ischemia

Congenital continuous retrograde basilar flow suggests type B interrupted aortic arch in a neonate: A case report

Reversed flow in the basilar artery can be acquired or congenital. Acquired reversed flow in the basilar artery can result from acute thrombosis of the basilar artery or retrograde vertebral artery flow. Congenital continuous retrograde basilar artery flow has not been described. We report a 2-day-old male presenting with hypocalcemic seizures which led us to obtain a Duplex echoencephalogram. An echocardiogram was subsequently ordered. In the coronal plane through the anterior fontanelle, retrograde flow was seen in the basilar artery and the right vertebral artery. In the axial plane through the temporal window, the flow was anteroposterior in both posterior communicating arteries. In the posterior cerebral arteries, the flow was retrograde in the P1 segment and anterograde in the P2 and P3 segments. An interrupted aortic arch was suspected. The echocardiogram showed a large perimembranous ventricular septal defect with bidirectional shunting, a hypoplastic and bicuspid aortic valve, an aortic arch interrupted between the left common carotid artery and the left subclavian artery (type B interrupted aortic arch), and a 5 mm patent ductus arteriosus with predominant right to left flow. Because of the patency of the large patent ductus arteriosus, our patient showed no sign of posterior circulation insufficiency. Prostaglandin E1 therapy was initiated immediately. Diagnosis of DiGeorge syndrome was proven. The infant underwent interrupted aortic arch repair and anterograde flow was established in the basilar artery. We conclude that congenital asymptomatic continuous retrograde flow in the basilar artery and left vertebral artery is a medical emergency as it implies the presence of type B interrupted aortic arch with large patent ductus arteriosus in a neonate.

Clinical Characteristics of Intracranial Reversed Vertebral Artery Flow Evaluated by Transcranial Color Flow Imaging

BACKGROUND

Carotid duplex ultrasonography (CUS) has been used to identify reversed vertebral artery flow (RVAF) at the extracranial cervical artery in some patients with subclavian steal syndrome. However, the characteristics of intracranial RVAF as evaluated by transcranial color flow imaging (TC-CFI), which can examine intracranial hemodynamics in a real-time and noninvasive fashion, remain unclear. The goal of this study was to analyze the prevalence of intracranial RVAF and its associated clinical characteristics.

METHODS

Subjects were consecutive patients who underwent TC-CFI and CUS. We evaluated blood flow in both intracranial vertebral arteries (VAs) from the suboccipital echo window using TC-CFI. RVAF was defined as a flow signal directed toward the probe. We calculated the prevalence of intracranial RVAF in our subjects. Then, we investigated vascular condition (ie, site of lesion, stenosis, occlusion, and dissection) using magnetic resonance angiography, computed tomography angiography , and CUS in patients with intracranial RVAF.

RESULTS

Seven hundred twenty patients (508 men; median age, 73 years) were included in this study from September 2007 to March 2013. Intracranial RVAF was seen in 12 patients (1.7%; 11 men; median age, 61 years). Among the 12 patients with intracranial RVAF, 8 patients (67%) had ischemia of the vertebrobasilar territory with distal VA occlusion, according to CUS. Of those patients, 6 (75%) had dissection of the VA.

CONCLUSIONS

TC-CFI detected intracranial RVAF in 1.7% of consecutive examinations in our facility. In vertebrobasilar territory stroke patients with intracranial RVAF, VA dissection may contribute to the development of stroke.

Usefulness of transcranial Doppler ultrasound in evaluating cervical-cranial collateral circulations

Transcranial Doppler (TCD) ultrasound is a noninvasive, safe and cost-effective bedside test for evaluating cerebrovascular circulation in real time. It has been rapidly evolving from a simple noninvasive diagnostic tool to an imaging model with a broad spectrum of clinical applications. TCD can show the spectral flow waveforms, blood flow direction, velocities and intensity in the intracerebral vessels, adding physiologic information to other imaging models. TCD can also detect collateral channels through the anterior communicating artery, posterior communicating arteries, reversed ophthalmic artery, leptomeningeal collaterals, reversed basilar artery and reversed vertebral artery caused by hemodynamically significant carotid or intracranial stenosis. This article gives a brief overview of its use in evaluation of collateral circulation in carotid and intracranial steno-occlusive disease.

Endovascular management of pediatric high-flow vertebro-vertebral fistula with reversed basilar artery flow. A case report and review of the literature

Vertebral artery arteriovenous fistula (VAVF) is mostly known as a post-traumatic and/or iatrogenic arteriovenous complication. However, spontaneous high-flow VAVF associated with flow reversal in the basilar artery has not been reported in children. We describe a unique asymptomatic presentation of a spontaneous high-flow VAVF associated with flow reversal in the basilar artery in a pediatric patient. The literature for classification, pathophysiology, treatment strategies, and post-procedural complications is also reviewed.