“Parent vessel-preserving strategies cannot be considered inferior to parent vessel occlusion [PVO],” concluded Gopinathan Anil, National University Hospital, Singapore, during his presentation on dissecting distal cerebellar artery aneurysms at the recent World Federation of Interventional and Therapeutic Neuroradiology (WFITN) congress. Based on the presented findings of Anil et al’s retrospective review on the management of such aneurysms, he urged delegates at the meeting to “attempt parent vessel preservation whenever feasible.”
This advocated technique deviates from conventional endovascular treatment for dissecting distal cerebellar artery aneurysms, as PVO is most commonly used. Yet, according to Anil, while PVO is well tolerated in “most patients”, ischaemic complications can be “significant and unpredictable”. Another factor that formed the study’s rationale was the fact that the literature focused on posterior inferior cerebellar artery (PICA), collectively addressing aneurysms at different locations, and of varying aetiologies. “Hence, extrapolating those experiences to customise patient management remains a challenge,” said Anil.
Anil and his team in Singapore aimed to review their current experience in the management of dissecting distal cerebellar artery aneurysms, placing an emphasis on the effectiveness of a parent vessel preserving strategy as compared to PVO.
The retrospective analysis included cases falling between November 2015 to October 2018, all distal cerebellar artery aneurysms (DCAA; >5mm from origin) treated by endovascular means. Saccular aneurysms near the origin of cerebellar artery were excluded. In total, 18 dissecting DCAA were identified: 13 in the PICA, three in anterior-inferior cerebellar artery, and two in superior cerebellar artery. Anil noted that the median patient age was 61 years (40–86), with a 5:1 female predominance.
In terms of treatment arms, nine (six in the PICA and three in the anterior-inferior cerebellar artery) patients were managed by parent vessel-preserving strategies. Of these, six were treated with isolated endovascular coiling and three with telescoping stents. The remaining nine (seven in the PICA and two in the superior cerebellar artery) were treated by PVO.
Anil reported that overall, a modified Rankin Scale (mRS) score of <2 occurred in seven of the nine patients managed by parent vessel-preserving strategies. Among these, class 1-modifed Raymond-Roy occlusion was achieved with coil embolisation in five of the six patients. One patient had a class 3a occlusion. Anil acknowledged that the follow-up DSA performed a week later showed some coil compaction with a 1.5mm deep and 3mm wide neck recurrence. Additionally, one rebleed occurred in a patient with bihemispheric PICA aneurysm. All patients treated with telescoping stents showed gradual occlusion of the aneurysm and no rebleed occurred. Anil added: “Although telescoping stents with their flow diverting effect can prevent a rebleed, managing antiplatelets in acute stenting can be a challenge of which the physician must be cognisant.”
In relation to the clinical findings of those managed with PVO, Anil reported that immediate occlusion was achieved in all cases. While there were no direct procedural complications encountered in any of the patients, except for the expected ischaemic changes when PVO was performed, Anil reported that three patients died during the admission, one due to rebleed.
These results led Anil to conclude: “Overall clinical outcomes were worse in patients who went for PVO, but [the outcomes] were not directly related to the treatment.” He said that when successfully implemented, preserving strategies can deliver “excellent clinical outcomes and eliminate the uncertain risk of ischaemic complications associated with PVO”.
Of importance, Anil said that in dissecting aneurysms, if the pseudo-sac is coiled as a parent vessel-preserving strategy, short interval follow-up and aggressive management of risk factors for rebleed is essential. Yet, he maintained: “Despite being widely practiced and often well tolerated, the unpredictable ischaemic risk associated with PVO or cerebellar arteries cannot be neglected.”