Objective Nutritional Index is Associated with Worse Cardiopulmonary Exercise Test Performance in Advanced Heart Failure Patients

Abstract

Purpose The prognostic nutritional index (PNI) is an easily obtainable marker of malnutrition. A lower PNI represents greater malnutrition risk and is associated with higher mortality in heart failure (HF) patients as well as worse outcomes with left ventricular assist device (LVAD) implantation. We sought to determine whether PNI is associated with the metabolic response assessed by cardiopulmonary exercise testing (CPET) in advanced HF patients, prior to LVAD implantation. Methods We retrospectively reviewed preoperative CPETs of patients who underwent LVAD implantation at an academic medical center between 1/2012 and 12/2019. Baseline demographics and key CPET parameters were recorded and PNI (10\u202f×\u202fserum albumin (g/dL)\u202f+\u202f0.005\u202f×\u202ftotal lymphocyte count) was noted if performed within 90 days of CPET. Pearson correlation coefficients and linear regression models were analyzed, to determine the relationship between the PNI and maximum oxygen uptake (VO2max) or minute ventilation/carbon dioxide production slope (VE/VCO2), respectively. Results There were 52 CPETs that met inclusion criteria, of which 50 had PNI values. The cohort (n=50) comprised of 72% male and 38% ischemic HF etiology. Median age was 57 years, BMI 32.2 kg/m2, and PNI 38 (IQR 29-43). The median CPET parameters achieved were exercise time 6.4 min, metabolic equivalents (METS) 3.5, respiratory exchange ratio (RER) 1.07, VO2max 12.2 mL/kg/min, VE/VCO2 slope 38.5. PNI correlated with both VO2max (r=0.43, p Conclusion Greater malnutrition risk, depicted by a lower PNI, was associated with higher risk CPET performance pre-LVAD implantation (lower VO2max and higher VE/VCO2). PNI maybe used as a potential target for future novel interventions at improving cardiometabolic health.