Frailty Measurement and Implications for Cerebrovascular Disease Management in a Veteran Based Population

Abstract

Rapid and objective preoperative assessment of patients undergoing carotid endarterectomy (CEA) remains difficult and variable. The Risk Analysis Index (RAI) is a validated medical record-based assessment of frailty that has been used to predict clinical outcomes for patients undergoing surgical procedures including CEA. We applied RAI to a veteran population following CEA for asymptomatic cerebrovascular disease and examined the factors related to post-operative morbidity and mortality. After obtaining IRB approval, Veteran Affairs Surgical Quality Improvement Program data was queried for CEA procedures from 2002 to 2015 for ICD-9 codes indicating asymptomatic patients. RAI was then calculated based on Veteran Affairs Surgical Quality Improvement Program variable medical record extraction. Three groupings of patients were undertaken including non-frail (RAI < 30), frail (RAI 30-34) and very frail (RAI ≥ 35). Chi squared and ANOVA were used to assess cohort differences. Binary logistic regression was used to evaluate predictors of post-operative stroke, myocardial infarction (MI), any complication, and death. Between 2002 and 2015, 37,873 asymptomatic patients underwent CEA. Over 98% (37,266) of the patients were male with an average age of 68.3 ± 8.55 years. The cohorts contained 82.8% (n=31,362), 12.4% (n=4,678), and 4.8% (n=1,833) for the non-frail, frail and very frail groups respectively. Frailty was associated with increased rates of post-operative stroke, MI, any complication, death, and longer hospital length of stay (P< 0.001). Operative time did not significantly differ between the groups. Increasing frailty was associated with having one or more complications (OR 1.69, 95% CI 1.50-1.90 for frail and OR 2.79, 95% CI 2.41-3.24 for very frail, (P< 0.001), post-operative stroke in frail (OR 1.33 95% CI 1.06-1.67) and very frail (OR 1.57 1 95% CI 1.14-2.16) patients, and MI in both frail (OR 1.68, CI 1.17-2.43) and very frail (OR 3.73, CI 2.52-5.51) patients. Frailty was also significantly associated with death with in very frail patients (OR 4.14, 95% CI 3.00-5.71, P< 0.001). Increasing frailty as determined by RAI was associated with worse post-operative outcomes in asymptomatic patients undergoing CEA. Higher RAI score cohorts were associated with higher rates of postoperative stroke, MI, complications, and death. We recommend the use of this frailty index as a screening tool to guide risk discussions with asymptomatic patients undergoing CEA.