Comparison of 3 Times a Week 4-and 5-Hour In-Center Hemodialysis Sessions with Use of Continuous Non-Invasive Hemodynamic Monitoring

Background: Very aggressive ultrafiltration rate (lasting 3.5-4 h) may result in inadequate hemodialysis (HD). Our aim was to characterize HD-induced cardiovascular adaptation and its links to fluid removal during 4-vs. 5-h HD sessions. Material/Methods: The study involved 50 HD patients. A Cardioscreen device (Messtechnik, Ilmenau, Germany) was used to perform non-invasive hemodynamic measurements during mid-week HD sessions. Body fluids and nutritional status were assessed with a Body Composition Monitor (Fresenius Medical Care). Clinical and laboratory data were also analyzed. Results: It was shown that when comparing 3 times a week 4-vs. 5-h dialysis sessions, body mass index (BMI [kg/m(2)]), Kt/V, and ultrafiltration volume (UFV [mL]) were significantly lower in the 4-h dialysis group (23.1 +/- 3.5 vs. 27.1 +/- 4.7; 1.36 +/- 0.28 vs. 1.55 +/- 0.23; 1770 +/- 601 vs. 2831 +/- 836; P< 0.05, respectively). Cardiac index (CI [L/min/m(2)]) and thoracic fluid content (TFC [1/kW]) were significantly reduced in 4-h dialysis sessions (3.1 +/- 0.6 to 2.7 +/- 0.7; 35.1 +/- 8.4 to 32.8 +/- 6.8; P< 0.05, respectively). In patients treated with 5-h dialysis sessions, we found that heart rate (HR [bpm]) was significantly increased (69 +/- 10 to 74 +/- 15; P< 0.05) and TFC was reduced (34.3 +/- 8.9 to 31.5 +/- 8.2; P< 0.05). In patients treated with 4-h dialysis sessions, systemic vascular resistance index (SVRI [dyn.s.cm(-5)/m(2)]) increased from 2369 +/- 799 before HD to 2592 +/- 735 after HD (P= 0.342). Conclusions: The obtained data indicate that in extended (5-h) HD sessions, hemodynamic compensation occurred with increased HR, while in short (4-h) HD sessions, compensation occurred with increased SVRI. Providing longer but less intensive HD is more physiologic than the conventional therapy, and will improve patient tolerability and clinical outcomes.