Cerebral Revascularization for Recalcitrant Steno-occlusive Cerebral Atherosclerotic Disease: An Updated Systematic Review of the Literature

Introduction: Ischemic steno-occlusive cerebrovascular disease includes extracranial carotid occlusive and intracranial atherosclerotic disease (ICAD). Despite the negative findings in COSS, several large centers continue to report favorable results for revascularization surgery in select patients. The aim of our study was to perform an updated systematic review to investigate the role of revascularization surgery for atherosclerotic steno-occlusive patients refractory to medical management in the modern era.

Methods: Five independent authors performed PRISMA-guided literature searches in October 2022 to identify articles reporting clinical outcomes in adult ICAD patients undergoing bypass. Primary endpoints used were perioperative and long-term ischemic strokes, intracerebral hemorrhage, bypass patency, and favorable clinical outcomes. Study quality was evaluated with Newcastle-Ottawa (NOS) and the Oxford Center for Evidence-Based Medicine scales.

Results: 6,709 articles were identified in the initial search; 50 articles were analyzed. A notable increase in the proportion of articles published over the past ten years was observed. There were 6046 total patients with 4447 bypasses performed over the period from 1978 to 2022. The average length of follow-up was 2.75±2.71 years. The average NOS was 6.23 out of 9 stars. Pre-COSS (Before 2011), the average perioperative stroke rate was 8.45%, the long-term stroke rate was 13.82%, and favorable outcomes were 69.94%. Post-COSS (After 2011), the perioperative stroke rate was 5.65%, the long-term stroke rate was 4.76%, and favorable outcomes were 89.41%. There was a significant difference in perioperative, long term stroke rates, and favorable outcomes comparing studies before and after COSS (p < 0.001, Chi-Square).

Conclusion : Based on a systematic review of 50 articles, the existing literature indicates that long-term stroke rates and favorable outcomes for surgical revascularization for steno-occlusive disease have improved over time and are much lower than previously reported. Improved diagnostic and surgical techniques may contribute to improved outcomes in appropriately selected patients suffering from refractory cerebrovascular atherosclerotic steno-occlusive disease.