Perfusion-bypass recipient mismatch as a potential risk factor for perioperative ischemic stroke following single-barrel STA-MCA bypass for symptomatic atherosclerotic carotid occlusive disease.

OBJECTIVE

EC-IC bypass for symptomatic atherosclerotic internal carotid and middle cerebral artery chronic occlusion (AIMCAO) failed to show benefit over medical management in previous randomized controlled trials. We explored how a perfusion-directed bypass targeting strategy impacts perioperative stroke risk for symptomatic AIMCAO.

METHODS

We conducted a single-institution, retrospective analysis of consecutive patients undergoing single-barrel STA-MCA bypass for symptomatic AIMCAO from 2019 to 2025. Matched and mismatched cohorts were created based on the congruity of dominant hypoperfusion on CTP and M4 recipients (frontal vs temporal). The primary outcome was the composite incidence of perioperative ipsilateral stroke and related death within 90 days following surgery.

RESULTS

The cohort included 43 bypasses (34 matched, 9 mismatched) for predominantly frontal dominant perfusion deficits (83.7%) due to chronic ICA occlusions. Demographic characteristics were largely balanced between cohorts. Bypass patency remained high (97.6%) over a median follow-up of 180 days. The primary outcome, comprised entirely of ipsilateral perioperative stroke, occurred at a higher observed rate in the mismatched cohort (33% vs 2.9%, p = 0.024). In univariable logistic regression, perfusion-bypass recipient mismatch was associated with increased odds of 90-day ipsilateral ischemic stroke and related death (OR 16.5, 95% CI [1.79, 367.3], p = 0.023).

CONCLUSION

Mismatch between dominant hypoperfused regions and bypass recipient vessel territories may represent a potential risk factor for perioperative ipsilateral stroke in STA-MCA bypass for AIMCAO. We propose that matching of M4 recipient to areas of predominant hypoperfusion may mitigate this risk. Further controlled, prospective studies are needed to fully elucidate this relationship.