Abstract 17471: Cardiorenal Syndrome Patients With High NT-proBNP and Cystatin C Levels and Patients With Irreversible Cardiorenal Syndrome Identified by Persistently High Levels of Cystatin C Have Worse Outcomes in Cardiac Resynchronization Therapy: The BIOCRT Study

Abstract

Introduction: Cardiorenal syndrome comprises of a heterogeneous group of acute and chronic cardiac and renal dysfunction. We examine the association of a dual marker strategy using amino-terminal pro brain natriuretic peptide (NT-proBNP, heart failure) and cystatin C (CysC, renal function) with major adverse cardiac events (MACE) in cardiac resynchronization therapy (CRT) patients. Methods: In 92 patients (age 66±13; 80% male; ejection fraction 26±7%), NT-proBNP and CysC levels were measured at CRT implantation, and 1 month. NT-proBNP>1000 pg/mL and CysC>1mg/L were considered high. At baseline, cardiorenal patients were defined as having high NT-proBNP and CysC. One month after implant, we categorized CRT patients as (1) irreversible cardiorenal if CysC was persistently high, (2) progressive cardiorenal with low transition to high CysC, (3) reversible cardiorenal with high transition to low CysC, and (4) "normal" with stable low CysC. MACE was defined as death, cardiac transplant, left ventricular assist device, and heart failure hospitalization by 2 years. Results: There were 25 (27%) MACE. Prior to CRT, 34 (37%) patients had cardiorenal syndrome. Compared to patients with low NT-proBNP and CysC levels, cardiorenal patients had >6-fold risk of MACE (adjusted HR 6.3, p=0.02) with an estimated 52% probability of having MACE (Figure A). One month after CRT, 33 (36%) patients were irreversible, 15 (16%) progressive, 7 (8%) reversible, and 37 (40%) "normal". Compared to "normal" and reversible patients (referent), irreversible patients had >4-fold risk of MACE (adjusted HR 4.7, p=0.002) with an estimated 52% probability of having MACE (Figure B) while progressors had similar MACE risk (adjusted HR 1.0, p=1.0). Conclusions: CRT patients with cardiorenal syndrome, especially irreversible, have worse prognosis compared to those with acute renal injury or "normal" renal function. Cardiorenal status by NT-proBNP and CysC can identify high-risk CRT patients.