Outcomes of high-flow cerebral vascular bypass operations: a single-centre retrospective review

Abstract

Introduction and Objective: Although the advent of pipeline flow diverters in the recent decade has largely replaced the need for bypass operations in aneurysm treatment, where aneurysms are not amenable to endovascular treatments, cerebral vascular bypasses remain to be the ultimate solution. [1] The procedure is also a strategy in treatment of Moyamoya disease, pseudoaneurysms, skull base tumours which encase great vessels and in stroke prevention. [2] Unfavorable outcomes of high-flow bypass have been reported, which include haemorrhagic transformation, perioperative ischaemia and graft occlusion. Nevertheless, high-flow bypass provides a better approximate of physiological condition than low-flow bypass and would be the preferred option where higher flow is preferred and scalp arteries are unavailable. [1] The outcome of high-flow bypass shows great variation and graft patency is the single most important indicator for operation success. Much of the current literature on high-flow bypass procedures are based on the Western populations. The resemblance and hence representativeness, in terms of disease characteristics and treatment response, between this locality and the Western populations are unproven. For instance, a large majority of pseudoaneurysms eventually indicating high-flow bypass operations arise as complications of radiation therapies for previous head and neck tumours, including the regionally endemic nasopharyngeal carcinoma. Nasopharyngeal carcinoma is less commonly seen in the Westerners. With the hope of providing data with better representation of local disease characteristics and treatment responses, we here present a retrospective review on the outcomes of high-flow bypass operations performed over a fifteen-year period in a regional hospital in Hong Kong. Method: Data on high-flow bypass performed between 2002 to 2017 at Queen Mary Hospital are retrieved from our database. Procedure indications, graft type, comorbidities, radiological (i.e. graft patency) and clinical outcomes, including ischaemic events, are collected and analyzed. Reference: 1. Sia, S.F. and M.K. Morgan, High flow extracranial-to-intracranial brain bypass surgery. J Clin Neurosci, 2013. 20(1): p. 1-5. 2. Lam, J.W., et al., Management of pseudoaneurysms of the internal carotid artery in postirradiated nasopharyngeal carcinoma patients. Laryngoscope, 2014. 124(10): p. 2292-6.