Serum Cystatin C as a Predictor of Early Outcomes and Long-Term Mortality in Contemporary LVAD Patients

Abstract

Serum creatinine (sCr) is routinely used in the evaluation of left ventricular assist device (LVAD) candidates. However, the prognostic value of sCr may be limited by the high prevalence of sarcopenia in this population. Cystatin C (CysC) is an alternative marker of renal function, which is less dependent on muscle mass. We aimed to investigate the association of pre-LVAD CysC and sCr with early post-operative outcomes and long-term mortality. CysC and sCr were concurrently measured prior to LVAD implant in 130 consecutive pts (age 59 ± 13, 15% F, 80% HM3) from 2/2016 to 8/2019. The primary endpoints were: 1) a composite of early post-LVAD outcomes, and 2) long-term mortality. The former included: i) death during index admission; ii) right ventricular failure (RVF) - need for right ventricular assist device or inotropic support ≥14 days; iii) acute kidney injury (AKI) - need for renal replacement therapy or sCr increase ≥4 mg/dL or ≥x3 times baseline. Secondary endpoints were the individual components of the composite endpoint and prolonged length of stay (pLOS), defined as LOS ≥ 30 d post-LVAD. Logistic and Cox proportional models regressed the endpoints on CysC and sCr. In pre-LVAD samples, median CysC and sCr were 1.40 (IQR: 1.10,1.87) mg/L and 1.39 (IQR: 1.07,1.79) mg/dL, respectively. The composite of early outcomes occurred in 72 (55%) pts: 10 (8%) in-hospital deaths, 43 (33.1%) RVF and 47 (36.2%) AKI. CysC outperformed sCr in the prediction of the composite of early post-LVAD outcomes. CysC, but not sCr, was associated with RVF and pLOS (Table). Death occurred in 20 (15%) pts over a median follow-up of 13 months. Pre-LVAD CysC, but not sCr was associated with an increased risk of long-term mortality (Table). In a contemporary cohort of LVAD pts, pre-LVAD CysC was associated with early post-operative outcomes as well as with long-term mortality. The use of CysC in the pre-operative assessment of LVAD candidates may improve risk stratification compared to sCr.