POS-245 CARDIORENAL SYNDROME IN PULMONARY AERTERIAL HYPERTENSION

Abstract

Volume overload in pulmonary arterial hypertension (PAH) is a frequent and early complication, and leads to right heart failure. However, the pathophysiology of volume overload and role of kidneys in sodium and water retention is not well studied and recognized. We aimed to identify factors associated with volume overload in PAH patients. We reviewed medical charts of consecutive 32 patients with PAH. Patients on loop diuretic were considered to be volume overloaded. Repeated measures of clinical and lab variables recorded at the time of each right heart catheterization (RHC) were included for analysis. For comparisons between diuretic and not-on-diuretic groups, we used independent t-test for normally distributed and Mann-Whitney U test for nonparametric variables. Mean age at last follow up was 51.2±11.6 years, 100% were white, 94% were female, and mean estimated glomerular filtration rate (GFR) was 93±19ml/min. Median follow-up was four years. Fifty-six percent patients were on loop diuretic. These patients on diuretic were significantly more edematous (1.24±1.37 vs. 0.27±0.63 score, p=0.005), had higher BMI (30.5±6.3 vs. 25.1±4.9 kg/m2, p=0.002) and covered less distance on 6 minute-walk test (360 [300,413] vs. 420 [385,464] meters, p=0.012) than patients not on diuretic. No difference was noted in age, gender, BP, NYHA class, or oxygen saturation. RHC were performed ≥2 times more often in diuretic vs. non-diuretic group (68% vs. 28.6%, p=0.03). On RHC, right atrial pressure (RAP) was significantly higher (7.9±4.2 vs. 3.8±3.2 mmHg, p=0.006) and there was trend towards higher mean pulmonary artery pressure (49±13.3 vs. 42±12.5 mmHg, p=0.08) in diuretic group with no difference in cardiac index or pulmonary vascular resistance. Serum alkaline phosphatase was higher (106.8±34.3 vs. 76.2±35.3 U/L, p=0.02) in diuretic group with no difference in other blood work including BNP and estimated GFR. There was no difference in proportion of patients on PAH-specific therapies. On follow-up, four patients in each group died or were lost to follow-up. High BMI and RAP, well-known factors associated with cardiorenal syndrome and volume overload in other edematous disorders were applicable in our PAH cohort as well suggestive of presence of similar pathways of impaired natriuresis despite normal GFR. Further studies are required to confirm these pathways which can guide appropriate early-on therapeutics.