Frailty Predicts Postoperative Functional Outcomes After Microsurgical Resection of Ruptured Brain Arteriovenous Malformations in Older Patients

Abstract

To determine the effectiveness of the modified Frailty Index-5 (mFI-5) in predicting postoperative functional outcome after microsurgical resection of ruptured brain arteriovenous malformations (bAVMs). A retrospective review was performed of patients undergoing microsurgical resection of acutely ruptured bAVMs. Demographics, bAVM characteristics, mFI-5, Ruptured Arteriovenous Malformation Grading Scale (RAGS) score, and Spetzler-Martin (S-M) grade were recorded. Predictive ability of mFI-5 for postoperative functional outcome measured by modified Rankin Scale (mRS) was assessed with univariate and multivariate logistic and linear regression. RAGS score and S-M grade alone were compared with adding mFI-5 to either RAGS score or S-M grade using area under the curve (AUC) analysis. In total, 109 patients were included. For every 1-point increase in mFI-5, there was a lower likelihood of good functional outcome (mRS score ≤2; odds ratio [OR], 0.33; confidence interval [CI], 0.15-0.60; P= 0.011). Healthy patients (mFI-5= 0) were more likely to have good postoperative outcomes versus frail patients (mFI-5 ≥1) (OR, 3.32; CI, 1.24-8.97; P= 0.017). In multivariate analysis controlling for RAGS score, for every 1-point mFI-5 increase, there was a decreased likelihood of postoperative good functional outcome (OR, 0.32; CI, 0.14-0.63; P= 0.0026) and mFI-5 did not significantly predict secondary outcomes. S-M grade with mFI-5 showed better discrimination for postoperative good functional outcome (AUC 0.616), compared with S-M grade alone (AUC 0.544). RAGS score with mFI-5 showed the best discrimination for postoperative good functional outcome (AUC 0.798), compared with RAGS score alone (AUC 0.721). Measuring frailty with mFI-5 additive to established bAVM grading systems may improve assessment of individual patient likelihood of postoperative good functional outcome after hemorrhagic bAVM resection.