Impact of Very Small Aneurysm Size and Anterior Communicating Segment Location on Outcome after Aneurysmal Subarachnoid Hemorrhage

Abstract

BACKGROUND:Very small anterior communicating artery aneurysms (vsACoA) of <5 mm in size are detected in a considerable number of patients with aneurysmal subarachnoid hemorrhage (aSAH). Single-center studies report that vsACoA harbor particular risks when treated.OBJECTIVE:To assess the clinical and radiological outcome(s) of patients with aSAH diagnosed with vsACoA after aneurysm treatment and at discharge.METHODS:Information on n = 1868 patients was collected in the Swiss Subarachnoid Hemorrhage Outcome Study registry between 2009 and 2014. The presence of a new focal neurological deficit at discharge, functional status (modified Rankin scale), mortality rates, and procedural complications (in-hospital rebleeding and presence of a new stroke on computed tomography) was assessed for vsACoA and compared with the results observed for aneurysms in other locations and with diameters of 5 to 25 mm.RESULTS:This study analyzed n = 1258 patients with aSAH, n = 439 of which had a documented ruptured ACoA. ACoA location was found in 38% (n = 144/384) of all very small ruptured aneurysms. A higher in-hospital bleeding rate was found in vsACoA compared with non-ACoA locations (2.8 vs 2.1%), especially when endovascularly treated (2.1% vs 0.5%). In multivariate analysis, aneurysm size of 5 to 25 mm, and not ACoA location, was an independent risk factor for a new focal neurological deficit and a higher modified Rankin scale at discharge. Neither very small aneurysm size nor ACoA location was associated with higher mortality rates at discharge or the occurrence of a peri-interventional stroke.CONCLUSION:Very small ruptured ACoA have a higher in-hospital rebleeding rate but are not associated with worse morbidity or mortality.

Commentary: Impact of Very Small Aneurysm Size and Anterior Communicating Segment Location on Outcome After Aneurysmal Subarachnoid Hemorrhage

“…2-4 On contrary, other authors concluded that aneurysms located in the anterior communicating complex are among those with the highest risk of rupture. 3-6 Authors 1 of this study reported that aneurysms smaller <5 mm comprised 12% of all ruptured and 33% of all ruptured anterior communicating artery (AcoA) aneurysms, congruent with the findings of previous studies. 4,5,7 Although not as significant as the findings by Waqas et al, 8 who reported 6-mm mean size of rupture aneurysms in the anterior circulation; it nevertheless reopens the known dilemma when counseling patients harboring innocent small AcoA aneurysm.…”

“…In conclusion, we congratulate Roethlisberger et al 1 for providing a unique insight into the characteristics of virtually all ruptured aneurysms treated in Switzerland, further emphasizing the dangerous nature of very small aneurysms of the anterior communicating complex.…”

“…Authors unfortunately did not report the timeframe of the rerupture, techniques/devices used or an association with a known residual aneurysm that could shine more light onto the possible mechanism. Roethlisberger et al 1 found very small aneurysm size to be associated with lower periprocedural stroke rate than their larger counterparts; however, it was significantly higher than that of surgical group. This trend was however universal across all aneurysms in all locations and not unique to the AcoA aneurysms.…”

“…This study 1 provides insight into outcomes after aneurysmal subarachnoid hemorrhage because the Swiss health care system allows treatment of specific diseases (eg, cerebrovascular pathologies) only in accredited centers. The results for this study are important because they encompass 8 neurovascular centers in Switzerland between 2009 and 2014, helping to limit the selection bias present in many other series.…”

“…This study 1 investigated the role of perioperative adverse events on the patients outcome and found significantly higher in-hospital rehemorrhage rates in very small AcoA aneurysms undergoing endovascular treatment compared with very small aneurysms in other locations, small/large AcoA aneurysms, or surgical clipping of very small AcoA aneurysms. This seems to be in contradiction with the reports by Zhao et al 10 ; however, they backed up by data from a multi-institutional rather than single-center study.…”