LAUSR

BACKGROUND Cardiorenal syndrome comprises a heterogeneous group of disorders characterized by acute or chronic cardiac and renal dysfunction. OBJECTIVE The purpose of this study was to determine the effect of cardiorenal status using a dual-marker strategy with amino-terminal pro-brain natriuretic peptide (NT-proBNP) and cystatin C on cardiac resynchronization therapy (CRT) outcomes. METHODS In 92 patients (age 66 ± 13 years; 80% male; left ventricular ejection fraction 26% ± 7%), NT-proBNP and cystatin C levels were measured at CRT implantation and at 1 month. NT-proBNP >1000 pg/mL and cystatin C >1 mg/L were considered high. Baseline cardiorenal patients were defined as having high NT-proBNP and cystatin C. At 1 month, CRT patients were categorized as (1) irreversible cardiorenal if cystatin C was persistently high; (2) progressive cardiorenal with transition from low to high cystatin C; (3) reversible cardiorenal with transition from high to low cystatin C; and (4) "normal" with stable low cystatin C. Outcomes were 6-month clinical and echocardiographic CRT response and 2 -year major adverse cardiovascular event (MACE). RESULTS Compared to patients with low NT-proBNP and cystatin C, cardiorenal patients had >9-fold increase risk of CRT nonresponse (odds ratio uncompensated 9.0; compensated 36.4; both P ≤.004) and >6-fold risk of MACE (hazard ratio uncompensated 8.5; P = .005). Compared to "normal" and reversible patients (referent), irreversible patients had a 9-fold increase for CRT nonresponse (odds ratio 9.1; P <.001) and had >4-fold risk of MACE (adjusted hazard ratio 5.1; P <.001). Irreversible patients were most likely echocardiographic CRT nonresponders. CONCLUSION Cardiorenal status by NT-proBNP and cystatin C can identify high-risk CRT patients, and those with both elevated concentrations have worse prognosis.