Backhaus SJ, Lange T, George EF, Hellenkamp K, Gertz RJ, Billing M, Wachter R, Steinmetz M, Kutty S, Raaz U, Lotz J, Friede T, Uecker M, Hasenfuß G, Seidler T, Schuster A
Circulation. 2021 Jan 21.
Background: Right heart catheterisation (RHC) using exercise-stress is the reference standard for the diagnosis of heart failure with preserved ejection fraction (HFpEF) but carries the risk of the invasive procedure. We hypothesized that real-time cardiovascular magnetic resonance (RT-CMR) exercise imaging with pathophysiologic data at excellent temporal and spatial resolution may represent a contemporary non-invasive alternative for diagnosing HFpEF.
Methods: The HFpEF stress trial (DZHK-17, NCT03260621) prospectively recruited 75 patients with echocardiographic signs of diastolic dysfunction and dyspnea on exertion (E/e’>8, New York Heart Association (NYHA) class ≥II) to undergo echocardiography, RHC and RT-CMR at rest and during exercise-stress. HFpEF was defined according to pulmonary capillary wedge pressure (PCWP ≥15mmHg at rest or ≥25mmHg during exercise stress). RT-CMR functional assessments included time-volume curves for total and early (1/3) diastolic left ventricular (LV) filling, left atrial (LA) emptying and LV/LA long axis strain (LAS).
Results: HFpEF patients (n=34, median PCWP rest 13mmHg, stress 27mmHg) had higher E/e’ (12.5 vs. 9.15), NT-proBNP (255 vs. 75ng/l) and LA volume index (43.8 vs. 36.2ml/m2) compared to non-cardiac dyspnea patients (n=34, rest 8mmHg, stress 18mmHg, p≤0.001 for all). Seven patients were excluded due to the presence of non HFpEF cardiac disease causing dyspnea on imaging. There were no differences in RT-CMR LV total and early diastolic filling at rest and during exercise-stress (p≥0.164) between HFpEF and non-cardiac dyspnea. RT-CMR revealed significantly impaired LA total and early (p<0.001) diastolic emptying in HFpEF during exercise-stress. RT-CMR exercise-stress LA LAS was independently associated with HFpEF (adjusted odds ratio 0.657, 95% confidence interval [0.516; 0.838], p=0.001) after adjustment for clinical and imaging parameters and emerged as the best predictor for HFpEF (area under the curve rest 0.82 vs. exercise-stress 0.93, p=0.029).
Conclusions: RT-CMR allows highly accurate identification of HFpEF during physiological exercise and qualifies as a suitable non-invasive diagnostic alternative. These results will need to be confirmed in multi-centre prospective research studies to establish widespread routine clinical use.
Clinical Trial Registration: https://www.clinicaltrials.gov Unique Identifier: NCT03260621.