Abstract 13267: Advanced Heart Failure With Reduced Ejection Fraction and Severe Mitral Insufficiency Compensate With a Higher Oxygen Peripheral Extraction to a Reduced Cardiac Output vs Oxygen Uptake Response to Maximal Exercise
Background: in heart failure (HF) the mitral regurgitation (MR) is clinical and prognostic relevant. Cardiopulmonary exercise testing (CPET) allows evaluating functional capacity and provides indexes for HF risk stratification such as peak oxygen consumption (VO2). Since MR determines a severity-related backward flow to left atrium, it may result in an unfavorable central blood flow exercise redistribution that is physiological relevant to VO2 increase. Aim: To evaluate the cardiac output (CO) and VO2 exercise-response in HF reduced ejection fraction (HFrEF) patients according to MR severity to dissect what mechanism may be predominant in the VO2 increase.
Methods: 104 HFrEF patients (mean age 64±11 y, male 72%, ischemic etiology 68%, mean LVEF 34±9%) underwent a maximal CPET (incremental ramp protocol) combined with exercise-echo. CO was non-invasive estimated by echo.
Results: Population was divided into 2 groups according to the rest MR: group A (n=80) non-severe MR and B (N=24) severe MR. Despite the groups did not differ in rest CO (A vs B 3.8±1 vs 3.4±1.8 L/min, p=ns) and VO2 (0.27±0.06 vs 0.28±0.09 L/min, p=ns) group B showed higher peripheral extraction (C(a-v)O2 8±2 vs 9±4 mL/100 mL, p=0.036) already at rest (Figure). At peak exercise group B had an impaired increase both in CO (7,0±2,0 vs 5,2±3,3 L/min) and VO2 (1,0±0,3 vs 0,8±0,3 L/min, p=0.001) partially compensated by a greater C(a-v)O2 contribution (15±4 vs 18±5 for A vs B, p=0.047). Conclusions: Severe MR and consequent partial abnormal CO redistribution to the pulmonary circulation seems a relevant pathophysiological mechanisms that limits overall exercise performance in HFrEF. In this high risk subset of patients peripheral extraction compensates for the reduced CO and makes the basis for novel perspectives in these patients.
Author Disclosures: G. Generati: None. F. Bandera: None. M. Pellegrino: None. V. Labate: None. F. Carbone: None. E. Alfonzetti: None. M. Guazzi: None.
- © 2015 by American Heart Association, Inc.