Discrepancy in the Diagnosis of Heart Failure with Preserved Ejection Fraction between Supine Versus Upright Exercise Hemodynamic Testing

BACKGROUND: Invasive exercise right heart catheterization is a gold standard in diagnosing heart failure with preserved ejection fraction (HFpEF). Body positions during the test influence hemodynamics. However, the discrepancy in HFpEF diagnosis between exercise testing in supine versus upright position is unknown. METHODS: We conducted a 2-center prospective study enrolling patients referred for exercise right heart catheterization for HFpEF. We performed a Supright protocol integrating submaximal supine bicycle ergometry (20 W) followed by maximal upright bicycle ergometry with a breath-by-breath oxygen analyzer. HFpEF hemodynamic criteria specific to testing positions were applied. Patients were considered to have concordant HFpEF if they met criteria in both positions or discordant HFpEF if they met criteria only in the supine position. RESULTS: Of 36 patients who met HFpEF criteria in supine position, 18 (50%) did not meet criteria in upright position (discordant HFpEF). Discordant HFpEF had less atrial fibrillation (0% versus 55%; P<0.001), lower left atrial volume (60±14 versus 77±21 mL; P=0.010), and lower H2FPEF score (2.1±1.3 versus 5.1±2.3; P<0.001). In supine position, pulmonary arterial wedge pressure was lower in discordant HFpEF at rest (15±4 versus 19±7 mm Hg; P=0.040). In upright position, pulmonary arterial wedge pressure was lower in discordant HFpEF both at rest (8±4 versus 14±6 mm Hg; P=0.002) and at peak exercise (14±4 versus 27±7 mm Hg; P<0.001). Pulmonary arterial wedge pressure/cardiac output slope was lower in discordant HFpEF (1.6±1.7 versus 3.6±2.9; P<0.001). Maximal workload (46±18 versus 49±24 W; P=0.59) or peak oxygen consumption (11.4±2.8 versus 12.9±3.4 mL/[kg·min]; P=0.15) was similar between groups. CONCLUSIONS: Half of patients who met HFpEF criteria in the supine position did not meet the criteria in the upright position. Patients with a discordant HFpEF phenotype had less structural and hemodynamic abnormalities compared with those with concordant HFpEF. A Supright exercise right heart catheterization approach is feasible and merits further investigation to determine the clinical implications of discordant exercise hemodynamic findings in supine and upright positions.