655 Determinants of exercise-induced pulmonary hypertension in patients with heart failure and systolic left ventricular dysfunction

Abstract

1 1 CHU Sart Tilman, Liege, Belgium Background: Pulmonary hypertension (PHT) and mitral regurgitation (MR) are frequently observed in heart failure patients. Although the role of MR in the genesis of PHT at rest has been described, the determinants of exercise in- duced PHT have not been examined. Methods: To evaluate the resting and exercise covariates associated with exercise induced PHT, 46 patients with left ventricular (LV) dysfunction (ejec- tion fraction: 30±6%) underwent quantitative exercise echocardiographic as- sessment of the LV systolic and diastolic (Early mitral inflow (E) and early annulus velocity) function, transtricuspid pressure gradient (TTPG), MR vol- ume and left atrial volume (LAV). Results: At rest, LV volumes, MR volume, E wave and LAV correlated with TTPG. In multivariate analysis, E wave (p=0.0003) and LAV (p=0.00001) emerged as independent determinants of the TTPG. At exercise, LV vol- umes, MR volume, and the TTPG calculated in resting conditions correlated with the peak TTPG. The TTPG at rest was the sole predictor of the TTPG at exercise (p=0.000001). However, the TTPG at rest did not correlate with the magnitude of increase in the TTPG during the test (r=0.12, p=ns). The rate of exercise dypnea was similar in patients with (40%) and without (44%) significant PHT at baseline (TTPG >40 mm Hg) (p=ns). At exercise, LV vol- umes and ejection fraction, MR volume, and LAV correlated with the peak TTPG. In multivariate analysis, peak ejection fraction (p=0.006) and peak MR volume (p=0.00001) were independently associated with peak TTPG. Patients with a larger exercise induced increase in TTPG (changes in TTPG >20 mm Hg; median value) interrupted more frequently the test for dyspnea as compared with those who had smaller changes (25% of cases vs 69% of cases; p=0.04). A larger rise in MR volume during exercise emerged as the sole independent determinant of exercise induced increases in TTPG. Conclusions: LA volume overload and LV diastolic function correlated with resting pulmonary pressure. Larger exercise induced increases in MR and limited contractile reserve (weaker changes in ejection fraction) strongly af- fected the level of pulmonary pressure at exercise. The magnitude of changes in pulmonary pressure during exercise mainly depends on the dynamic behaviour of MR. 656 Functional capacity is related to contractile reserve in patients with left ventricular dysfunction In patients (pts) with heart failure the reduction of functional capacity is asso- ciated with poor long-term prognosis and the presence of contractile reserve is a favorable sign. In these pts, functional capacity is not strictly related to the baseline left ventricular ejection fraction (LVEF). Cardiopulmonary exercise testing (ET) is commonly utilized in this setting to evaluate functional capac- ity. We hypothesized that in pts with ischemic or nonischemic cardiomyopa- thy and left ventricular (LV) dysfunction, functional capacity measured by car- diopulmonary ET is related to the presence of contractile reserve assessed by