CHANGES ON RIGHT VENTRICULAR DIMENSIONS, FUNCTION, AND PULMONARY CIRCULATION LOADING ACCORDING TO THE DEGREE OF INTERDIALYTIC WEIGHT GAIN IN MAINTENANCE HEMODIALYSIS PATIENTS

Abstract

Objective: The right ventricle (RV) is a thin-walled cardiac chamber, whose sizing and pressure characteristics are susceptible to altered loading conditions. This study aimed to investigate changes in RV's function, right heart's dimensions, and pulmonary pressures in relation to the degree of fluid accumulation between hemodialysis sessions, evaluated according to the recommended threshold of interdialytic-weight-gain corrected for dry weight (IDWG%). Design and method: Forty-one patients receiving standard thrice-weekly hemodialysis were divided into a higher (> 4.5%) and a lower ( < 4.5%) IDWG% group for the present analysis, according to the recommended higher threshold of IDWG%. All participants underwent a 2-dimensional echocardiographic assessment at the start and the end of the 3-day and the 2-day interdialytic interval in a crossover design. Results: RV systolic pressure (RVSP) increments were more pronounced in the higher compared to the lower IDWG% group (16.43 ± 5.37 vs 14.11 ± 13.38 mmHg respectively, p = 0.015) over the 3-day interval, while changes in RV filling pressures, assessed by RV E/Em did not differ significantly between the two groups (p = 0.84). Significant right heart chambers’ enlargement was observed in both groups and during both intervals, but a more prominent dilatation of inferior vena cava was noted in patients with higher IDWG% (0.44 ± 0.25 vs 0.2 ± 0.31cm, p = 0.014) over the 2-day interval. Conclusions: During the 3-day interdialytic interval, pulmonary circulation is particularly overloaded in patients with fluid accumulation higher that the recommended thresholds, as evidenced by higher RVSP elevations. This finding may add another plausible mechanism for increased cardiovascular morbidity and mortality during the long interval.