Diagnosis of HFpEF With Real-Time Exercise CMR

Exercise real-time cardiovascular magnetic resonance (RT-CMR) was found to represent an effective, non-invasive alternative to right heart catherization (RHC) for the diagnosis of heart failure with preserved ejection fraction (HFpEF), according to a study published in Circulation.

Patients (N=75) referred to the Heart Center Goettingen in Germany for echocardiography were prospectively enrolled in this study. All patients underwent RT-CMR, RHC, and echocardiography.

Patients with HFpEF vs non-cardiac dyspnea (n=34 in each group) were significantly older (P =.034), and a greater number had atrial fibrillation (P =.004), and elevated levels of N-terminal pro-brain natriuretic peptide (P <.001).

Patients with HFpEF vs non-cardiac dyspnea had higher pulmonary capillary wedge pressure (13 mm Hg vs 8 mm Hg, respectively; P <.001) and pulmonary artery pressure at rest (22 mm Hg vs 17 mm Hg, respectively; P <.001), and during stress (pulmonary capillary wedge pressure: 27 mm Hg vs 18 mmHg, respectively; P <.001; pulmonary artery pressure: 44 mm Hg vs 34 mm Hg; P <.001). Among patients with HFpEF, 44% were diagnosed at rest and 56% during stress.

Patients with HFpEF had higher E/e’ at rest (12.5 vs 9.15, respectively; P <.001) and left atrial volume index (43.8 mL/m² vs 36.2 mL/m², respectively; P =.001) compared with patients with non-cardiac dyspnea.

Real-time left atrial long axis strain and left atrial ejection fraction at rest were found to be impaired in patients with HFpEF compared with those with non-cardiac dyspnea (15.6% vs 22.7%, respectively; P <.001 and 34.2% vs 39.9%, respectively; P =.002). During the stress RT-CMR (bicycle exercise), patients with HFpEF vs non-cardiac dyspnea had lower left ventricular long axis strain (13.5% vs 13.9%, respectively ; P =.001) and diastolic filling slope (5.2 vs 5.5 L/m² body surface area, respectively; P =.034), lower left atrial long axis strain (15.7% vs 28.1%, respectively; P <.001) and ejection fraction (32.2% vs 44.9%, respectively; P =.002), and higher left atrial early diastolic emptying (-2.2 vs -3.6 mL/m² body surface area; P <.001), diastolic emptying slope (-1.3 vs -2.1 mL/m² body surface area, respectively; P <.001), and total diastolic emptying (-12.3 vs -13.8 mL/m² body surface area, respectively; P =.033).

An area under the receiver operating characteristic curve (AUC) analysis conducted to determine the accuracy of RT-CMR detection of HFpEF indicated that all conventional, left ventricular function, and left atrial function parameters at rest (AUC range, 0.51-0.84) and during stress (AUC range, 0.59-0.93) had high predictive abilities. Rest and stress assessments differed significantly for left atrial ejection fraction (P =.002), left atrial emptying slope (P =.008), and left atrial long axis strain (P =.029).

This study was limited by its single-center design with a small study population.

“Among the various functional parameters in this early clinical trial, left atrial longitudinal shortening during exercise stress emerged as the best independent predictor of invasively proven HFpEF and should be considered for improved clinical detection and management of patients with HFpEF once these results are confirmed in multi-centre prospective research studies,” concluded the study authors.

Reference

Backhaus S J, Lange T, George E F, et al. Exercise-Stress Real-time Cardiac Magnetic Resonance Imaging for Non-Invasive Characterisation of Heart Failure with Preserved Ejection Fraction: The HFpEF Stress Trial. [published online January 21, 2021] Circulation. doi:10.1161/CIRCULATIONAHA.120.051542