Utility of the Modified Frailty Index to Predict Cardiac Resynchronization Therapy Outcomes and Response

The aim of the present study was to investigate the utility of the modified frailty index (mFI) to predict outcomes in patients who underwent cardiac resynchronization therapy (CRT) device implantation. A retrospective cohort study of patients undergoing CRT implantation or upgrade over a 5-year period was performed. The relation between the preprocedural 11-component mFI and clinical outcomes including 1-year mortality, periprocedural and 30-day adverse events, 30-day readmission, length of hospitalization after procedure, and response to CRT defined by changes in left ventricular ejection fraction and end-diastolic volume were studied. Of 283 patients studied, 134 (47.3%) were classified as frail (mFI ≥3). Frailty was associated with an increased risk of 1-year mortality (hazard ratio 5.87, p = 0.033 in multivariate analysis), and increased frequency of adverse events (p = 0.013), 30-day readmission (p = 0.0077), and postprocedural length of stay ≥3 days (p = 0.0005). Frail patients had significantly less echocardiographic response to CRT compared with nonfrail patients with change in left ventricular ejection fraction 6% versus 12% (p = 0.004) and change in left ventricular end-diastolic volume -19.9 versus -43.3 ml (p = 0.006). In conclusion, frailty as assessed by the mFI is associated with an increase in 1-year mortality, adverse events, 30-day readmission, length of stay, and poorer response to CRT after implantation.