Subarachnoid Hemorrhage Due to Rupture of Vertebral Artery Dissecting Aneurysms: Treatments, Outcomes, and Prognostic Factors

BACKGROUND

Mortality rate after subarachnoid hemorrhage due to rupture of vertebral artery dissecting aneurysms (VADAs) is high; endovascular coil trapping is the first-line therapy to prevent rerupture. To select optimal treatments, the positional relationship between the VADA and posterior inferior cerebellar artery (PICA) and the morphology of the contralateral vertebral artery must be considered, and outcome predictors of different treatment methods and their possible complications must be identified.

METHODS

We retrospectively studied 44 patients with ruptured VADAs who had undergone endovascular or surgical treatment. VADA morphology was assessed on conventional preoperative angiograms, and VADAs were categorized based on their site in relation to the PICA. VADA site, treatment method, and complications were used to identify prognostic factors.

RESULTS

The sites of the 44 VADAs were PICA-proximal (n = 3), PICA-distal (n = 22), PICA-absent (n = 7), and PICA-involved (n = 12). Treatments included internal coil trapping (n = 30), proximal coil occlusion (n = 5), and stent placement (n = 3); surgical flow alteration via an occipital artery-PICA bypass and ligation at the proximal vertebral artery and the PICA origin was performed in 6 patients. Periprocedural rebleeding was associated with a poor outcome. Internal coil trapping prevented the rerupture of PICA-proximal and PICA-absent VADAs, and flow alteration prevented rerupture of PICA-involved VADAs; there were no complications directly attributable to these procedures.

CONCLUSIONS

Periprocedural rebleeding was a poor prognostic factor. Internal trapping of PICA-proximal and PICA-absent VADAs and flow alteration in PICA-involved VADAs prevented rerupture.

Risk factors for medullary infarction after endovascular trapping of vertebral artery dissecting aneurysms

Internal trapping (IT) is a treatment option for intracranial vertebral artery dissecting aneurysms (VADAs). Medullary infarction (MI) is a complication linked to this treatment. This study aims to clarify the outcomes of IT for VADAs and the risk factors for MIs. We retrospectively reviewed the databases from 2010 to 2017 to identify patients with VADAs treated by IT at seven collaborating institutions. Radiological findings, clinical courses, and outcomes were analyzed. Perforating arteries were classified into terminal or longitudinal types using preoperative angiography. IT was completed in 90 patients (74 ruptured and 16 unruptured VADA). Postoperative rebleeding did not occur in any ruptured VADA patients. Postoperative MRI detected MIs in 26 patients (28.9%). The incidence of MIs in the ruptured VADA (32%) was higher compared with that in the unruptured VADA (13%), though it was not significant. In the MI group, the occlusion or blind alley of the terminal-type and longitudinal-type perforator was confirmed in 23 patients (88%) and 11 patients (42%), respectively. The occlusion or blind alley of the terminal-type perforator was an independent risk factor for MIs in the logistic regression analysis (OR 5.81; 95% CI 1.34-25.11; p = 0.018). In ruptured VADA, postoperative MI (OR 12.2; 95% CI 3.19-64.55; p = 0.0001) and high-grade SAH (OR 8.02; 95% CI 2.32-37.70; p = 0.0006) were independent risk factors of an unfavorable clinical outcome. In conclusion, MIs were an independent risk factor for unfavorable outcomes after IT, especially for a ruptured VADA. The occlusion or blind alley of the terminal-type perforator caused by the IT was associated with postoperative MIs.

Dissection of the Vertebral Artery Fenestration Limb Presenting with Occlusion After Rupture

BACKGROUND

Dissection of a vertebral artery (VA) fenestration is extremely rare. We herein present the first case of a patient who presented with the dissection of a VA fenestration limb accompanied by occlusion after rupture, who was treated with internal trapping of the dissected limb and the parent artery proximal to the fenestration.

CASE DESCRIPTION

A 55-year-old man presented with sudden headache and altered consciousness. Computed tomography at admission showed subarachnoid hemorrhage. Angiography showed occlusion of the inner limb of the vertebrobasilar junction fenestration, and the occluded ends had a tapered shape, suggesting the occlusion of the dissection of the inner limb after rupture. Angiography immediately before embolization revealed inner limb recanalization with an irregular string sign; thus only the inner limb was embolized. Angiography after embolization showed near-complete suppression of the blood flow in the inner limb; however, a slight antegrade flow through the coil mass was observed in the late phase. The procedure was finished with the expectation of complete occlusion over time with natural heparin reversal. Angiography 8 days after embolization revealed a significant increase in antegrade blood flow through the coil mass within the inner limb. Therefore additional embolization of the parent artery proximal to the fenestration was performed, which achieved complete occlusion.

CONCLUSIONS

The embolization length was limited and the antegrade blood flow through the other limb remained during internal trapping for the dissected VA fenestration limb; therefore careful observation of the blood flow to the dissected segment after embolization is necessary.

Vertebral artery dissecting aneurysm treated by internal trapping via the contralateral vertebral artery: A case report

A 42-year-old man with a history of sudden onset of severe headache followed by consciousness disturbance was brought to our hospital. Radiological examinations revealed subarachnoid hemorrhage, associated with rupture of a left vertebral artery dissecting aneurysm. Initially, internal trapping was attempted via the ipsilateral vertebral artery. However, the microcatheter could not be navigated through the true lumen to the distal side of the vertebral artery. Subsequently, therefore, the guiding catheter was placed in the right vertebral artery, and the microcatheter was retrogradely navigated successfully through the lesion to the proximal side of the left vertebral artery. Finally, the lesion was completely embolized with electrodetachable coils without complications. However, the patient died after the operation because of deterioration of the general condition. The postmortem examination revealed how an intimal flap had interfered with the antegrade navigation of the microcatheter in the lesion. The present case showed that endovascular treatment for a vertebral artery dissecting aneurysm via the contralateral vertebral artery may be a useful option in cases where antegrade navigation of the microcatheter via the ipsilateral vertebral artery is found to be difficult.