Presenting NIHSS predicts 90-day functional outcome after mechanical thrombectomy for basilar artery occlusion: A systematic review and meta-analysis

The prediction of outcome after mechanical thrombectomy (MT) of basilar artery occlusion (BAO) remains an area of investigation. The objective of this study was to evaluate the prognostic role of presenting National Institute Health of Stroke Scale (NIHSS) scores in predicting favorable 90-day functional outcome. A survey of 7 electronic databases from inception to May 2020 was conducted following PRISMA guidelines. Articles were screened against pre-specified criteria. Multivariate odds ratios (ORs) for favorable 90-day function outcome (modified Rankin Score 0-2) were extracted and pooled by meta-analysis of proportions with random effects modeling. A total of 10 individual studies satisfied criteria for selection and described a total of 941 BAO patients managed by MT. Analysis revealed 590 (63%) males with a mean age of 66.6 years. The median presenting NIHSS was 19, and 316 (34%) patients were reported to have a favorable functional status 90-days after treatment. Lower presenting NIHSS scores independently and significantly predicted favorable 90-day functional outcome in BAO patients with a pooled OR of 0.89 (95% CI, 0.87-0.92; I-2 = 18%; P-heterogeneity = 0.28). Metaregression did not detect any clinical parameter that influenced this trend direction or its significance, and bias assessments were unremarkable. We confirm in this study via a consensus within the literature that the presenting NIHSS score predicts 90-day functional outcome in BAO patients treated by MT. Further, its standardized use allows more meaningful comparisons between interventions and anatomical locations.