Quantitative angiographic haemodynamic evaluation of bypasses for complex aneurysms: a preliminary study

Objective Open microsurgery,often with bypass techniques,is indispensable for complex aneurysms.To date,it remains unknown whether arterial anatomy or quantitative blood flow measurements can predict insufficient flow-related stroke(IRS).The present study aimed to evaluate the risk factors for IRS in patients treated with open microsurgery with bypass procedures for complex internal carotid artery aneurysms.Methods Patients with complex aneurysms undergoing bypass surgery were retrospectively reviewed.The recipient/donor flow index(RDFI)was preoperatively evaluated using colour-coding angiography.RDFI was defined as the ratio of the cerebral blood volume of the recipient and donor arteries.The sizes of the recipient and donor arteries were measured.The recipient/donor diameter index(RDDI)was then calculated.IRS was defined as the presence of new postoperative neurological deficits and infarction on postoperative CT scans.We assessed the association between RDFI and other variables and the IRS.Results Twenty patients(38±12 years)were analysed.IRS was observed in 12 patients(60%).Patients with postoperative IRS had a higher RDFI than those without postoperative IRS(p<0.001).RDDI was not significantly different between patients with and without IRS(p=0.905).Patients with RDFI>2.3 were more likely to develop IRS(p<0.001).Conclusion Quantitative digital subtraction angiography enables preoperative evaluation of cerebral blood volume.RDFI>2.3,rather than RDDI,was significantly associated with postoperative IRS.This preoperative evaluation allows appropriate decisions regarding the treatment strategy for preventing postoperative IRS.

Effects and safety of aspirin use in patients after cerebrovascular bypass procedures

Object Superficial temporal artery to middle cerebral artery(STA-MCA)bypass is the most effective treatment for Moyamoya disease(MMD).In this study,we aimed to assess whether aspirin improves STA-MCA bypass patency and is safe in patients with MMD.Methods We performed a retrospective medical record review of patients with ischaemic-onset MMD who had undergone STA-MCA bypass at two hospitals between January 2011 and August 2018,to clarify the effects and safety of aspirin following STA-MCA bypass.The neurological status at the last follow-up(FU)was compared between patients with FU bypass patency and occlusion.Results Among 217 identified patients(238 hemispheres),the mean age was 41.4±10.2 years,and 51.8%were male;the indications for STA-MCA bypass were stroke(48.2%),followed by a transient ischaemic attack(44.0%).Immediate bypass patency was confirmed in all cases.During the FU period(1.5±1.5 y),15 cases were occluded at FU imaging,resulting in an overall cumulative patency rate of 94%.The patency rates were 93%and 94%in the short-term FU group(n=131,mean FU time 0.5±0.2 years)and long-term FU group(n=107,mean FU time 4.1±3.5 years),respectively.The STA-MCA bypass patency rate in the aspirin group was higher than that in the non-aspirin group(98.7%vs 89.7%;HR 1.57;95%CI 1.106 to 2.235;p=0.012).No significant difference in the FU haemorrhagic events was observed between the aspirin and non-aspirin groups.Conclusions Among adult patients with ischaemic-onset MMD undergoing STA-MCA bypass procedures,aspirin might increase the bypass patency rate,without increasing the bleeding risk.FU bypass patency may be associated with a better outcome.Additional studies,especially carefully designed prospective studies,are needed to address the role of aspirin after bypass procedures.