Diagnosing HFpEF in Patients With Unexplained Dyspnea by Using Invasive Left Ventricular Pressure-Volume Loops

Diagnosing heart failure with preserved ejection fraction (HFpEF) remains challenging. Noninvasive diagnostic algorithms have been proposed but not tested against the gold standard, ie, invasive measurement of left ventricular (LV) pressure-volume loops (PVL). This study's aim was to estimate the prevalence of HFpEF in euvolemic patients with unexplained exertional dyspnea by using LV PVL and to validate noninvasive diagnostic algorithms.

We included patients with unexplained exertional dyspnea, preserved LV ejection fraction ≥ 50% and without hemodynamically relevant coronary artery disease. Patients were evaluated at rest, during arm ergometric exercise and during temporal preload reduction by right-heart catheterization and real-time continuous LV PVL. HFpEF was defined as either elevated LV filling pressures at rest or during exercise or without elevated filling pressures but with prolonged relaxation or increased LV stiffness. The primary endpoint was the percentage of patients with confirmed HFpEF. Secondary endpoints included differences in the H₂FPEF and HFA-PEFF scores in HFpEF vs non-HFpEF patients. We recruited 30 patients, and 28 patients (mean age 64.4 ± 9.7 years, 57% female) were included in the final analysis. Of those patients, 26 (93%) had HFpEF with either elevated (n = 11) or without elevated filling pressures (n = 15). Noninvasive diagnostic scores had excellent specificity but lacked sensitivity for HFpEF.

Half of the patients with HFpEF had normal right-heart catheter hemodynamics, but they fulfilled HFpEF diagnostic criteria by showing impaired relaxation or LV chamber stiffness. Further research might focus on understanding the clinical relevance of this group and on improving its detection and treatment.