Bypass and Deconstructive Technique for Hunt and Hess Grade 3–5 Aneurysmal Subarachnoid Hemorrhage Deemed Unfavorable for Endovascular Treatment: Case Series of Outcomes and Comparison with Clipping

Background

Intracranial bypass to treat ruptured aneurysms has been well described in the literature but is largely deferred in patients with higher Hunt and Hess (H & H) grades due to complexity and length of surgery, risk of inducing vasospasm, and poor prognosis. However, there is a paucity of data and no direct comparison with more traditional open surgical techniques. This study investigated outcomes in patients with H & H grade 3–5 aneurysmal subarachnoid hemorrhage (aSAH) unfavorable for stand-alone endovascular treatment managed with bypass compared with direct surgical clipping.

Methods

A prospective database of patients treated for aSAH with H & H grade 3–5 between 2013 and 2018 was retrospectively analyzed. Complications and functional status at discharge and latest follow-up were compared between patients who underwent bypass surgery versus direct clipping.

Results

Twenty-three patients underwent revascularization, and 60 underwent clipping alone. There were no significant differences in all-cause 30-day mortality (15% vs. 16%; P = 0.97) or Glasgow Outcome Scale and modified Rankin Scale at discharge or median 8-month follow-up (P > 0.67). There was a higher overall stroke rate with revascularization (P = 0.004), specifically endovascular treatment-related stroke (P = 0.049), with no difference in surgical (P = 0.47) or vasospasm-related stroke (P = 0.53). There were no differences in overall complications, medical complications, seizures, reruptures, hydrocephalus, or perioperative death (P > 0.05).

Conclusions

Bypass is a viable option for patients presenting with higher H & H grade aSAH deemed unfavorable for stand-alone endovascular therapy. Despite obvious differences in aneurysm complexity and a higher risk of stroke, functional outcomes with revascularization can be comparable with clipping in this high-risk patient cohort.

Introduction

Mortality rates for patients with higher-grade aneurysmal subarachnoid hemorrhage (aSAH) remain significant despite recent advances in management.^1,2 One large 2015 study reported in-hospital mortality rates of 9%, 24%, and 71% for patients with Hunt and Hess (H & H) grades 3, 4, and 5 aSAH, respectively,³ with similarly high rates reported in other works irrespective of treatment modality (surgical or endovascular).^2,4, 5, 6, 7, 8, 9, 10 Despite the demonstrated importance of early aneurysm securement following higher-grade aSAH,^2,7,9 treatment of patients with higher-grade hemorrhages from complex aneurysms remains challenging.

Endovascular approaches have increasingly become the first-line treatment for ruptured aneurysms following the International Subarachnoid Aneurysm Trial,¹¹ although open surgical approaches remain relevant due to the higher recurrence risk, potential need for antiplatelet therapy, and inability to treat certain complex aneurysms with endovascular techniques (see Table 1 for a summary of complex aneurysm characteristics).12, 13, 14, 15 Recent data also suggest that the safety profile of endovascular approaches in daily clinical practice may be overestimated.¹⁶ Although most complex aneurysms requiring open surgery can be treated with primary clip reconstruction, in select cases where preservation of the parent and/or daughter vessel(s) is not possible, bypass combined with clipping or endovascular sacrifice can be employed. Although there is ample literature supporting bypass for the treatment of complex aneurysms, it is often deferred in patients with higher H & H grades due to the complexity and length of surgery, the worry of inducing vasospasm, and the poor prognosis in this patient subset.^13,17,18 Accordingly, there is a paucity of data on outcomes after bypass in patients with higher H & H grade aSAH, and there are no prior studies directly comparing bypass versus clipping in this patient cohort.

The primary aim of this study is thus to investigate the safety and clinical outcomes of bypass (combined with clipping or endovascular sacrifice) for patients with higher-grade aSAH. Secondarily (acknowledging the obvious differences in aneurysm complexity between treatment groups), the outcomes of bypass versus clipping alone for higher-grade aSAH were compared.