Cystatin C as a predictor of mortality and cardiovascular morbidity after cardiac resynchronization therapy.

BACKGROUND Cardiac resynchronization therapy (CRT) has been reported to improve symptoms and cardiac performance in patients with severe heart failure (HF), but CRT recipients with advanced HF do not always experience improved mortality rates. Cystatin C has recently been involved in HF, but the association of serum cystatin C level with adverse events and long-term prognosis after CRT is unknown. This study investigated whether cystatin C level can predict mortality and cardiovascular events after CRT. METHODS AND RESULTS A total of 117 consecutive patients receiving a CRT device for the treatment of advanced HF were assessed according to cystatin C level and long-term outcome after implantation of the device. Over a median follow-up of 3.2 years, 34 patients (29.1%) died and 59 patients (50.4%) developed cardiovascular events. Kaplan-Meier survival analysis indicated that elevated cystatin C level was significantly associated with higher all-cause mortality and prevalence of cardiovascular events, including hospitalization for progressive HF. After multivariate Cox regression analysis, serum cystatin C level and QRS duration, but not conventional echocardiographic parameters, were found to independently predict all-cause death or cardiovascular events. Of importance, only cystatin C level was an independent predictor of all-cause mortality after CRT. CONCLUSIONS Cystatin C level independently predicts cardiac mortality or morbidity in patients receiving CRT. The assessment of cystatin C level could provide valuable information about long-term prognosis after CRT.