Determinants of pulmonary artery hypertension at rest and during exercise in patients with heart failure

Abstract

Pulmonary hypertension, a marker of poor prognosis in heart failure, may develop or increase during exercise. We sought to examine the determinants of pulmonary hypertension at rest and during exercise in heart failure patients. Forty-six patients with left ventricular (LV) dysfunction (ejection fraction: 30 +/- 6%) underwent a semi-recumbent, incremental bicycle exercise Doppler echocardiography. LV systolic and diastolic function, pulmonary artery systolic pressure (PASP), functional mitral regurgitation (MR), and left atrial volume were quantified at rest and during exercise. Wide changes in PASP at exercise were unrelated to PASP at rest (r = 0.12). Independent predictors of PASP at rest were left atrial volume (P = 0.006), E-wave velocity (P = 0.02), mitral tenting area (P = 0.005), and mitral effective regurgitant orifice (ERO) (P = 0.02). The incidence of dyspnoea was similar in patients with and without moderately severe pulmonary hypertension at baseline. At peak exercise, LV ejection fraction (P = 0.03) and mitral ERO (P = 0.008) were independently associated with PASP. Patients with a larger exercise increase in PASP (>60 mmHg) interrupted frequently exercise for dyspnoea (70 vs. 27%; P = 0.04). A larger rise in mitral regurgitant volume during exercise emerged as the single determinant of exercise-induced increases in PASP. In patients with HF, left atrial volume, mitral deformation, and mitral regurgitant orifice correlated with pulmonary pressure at rest, whereas dynamic MR and limited contractile reserve correlated with pulmonary pressure at exercise. The magnitude of pulmonary pressure during exercise in these patients mainly depends on dynamic MR.