Comparison of Hemodynamic Performance of Transcatheter Aortic Valve Replacement With Supra-Annular Self-Expanding Versus Balloon-Expandable Valves Assessed by Exercise Cardiovascular Magnetic Resonance

Project Overview/Summary Transcatheter aortic valve replacement (TAVR) is an alternative to open heart surgery for the treatment of severe aortic stenosis, and has recently been approved for low surgical risk patients. This has resulted in a shifting of TAVR patient demographics to younger and more active individuals. It is, therefore, imperative to deliver excellent hemodynamics after valve replacement to enable patients to recover an active lifestyle with enhanced exercise capacity. Several studies, mostly conducted with resting echocardiogram have suggested self-expanding valves (SEV) Evolut R, Evolut PRO, Evolut PRO+ (Medtronic , Minneapolis, MN) are associated with favorable hemodynamics, which may allow for improved exercise capacity in active patients.

Currently, there are different TAVR valves are commercially available in the United States. The Sapien 3 valve (Edwards Lifesciences, Irvine, CA) is an annular, balloon expandable valve (BEV) and the Evolut PRO+ valve features a supra-annular design and is a SEV. A recent study utilizing resting echocardiogram demonstrated better hemodynamics of supra-annular SEV compared with BEV, mostly in patients with smaller annuli.

Cardiac magnetic resonance (CMR) has emerged as an important tool in the non-invasive assessment of patients with valvular heart disease. While CMR has been used for the diagnosis and quantification of valvular heart disease, there is a paucity of data on its use for the assessment of valvular hemodynamics in the post TAVR setting. Furthermore, it would be of utmost importance to understand how these devices perform during exertion. Of note, cardiac magnetic resonance techniques permit quantification of the myocardial extracellular volume fraction (ECV), representing a surrogate marker of reactive interstitial fibrosis, and late gadolinium enhancement (LGE), representing replacement fibrosis or scar. ECV and LGE have been independently linked with heart failure (HF) events.

Several studies have demonstrated that non-invasive CMR can be used to calculate non-invasive pressure-volume loops using cine imaging and non-invasive brachial blood pressure. This enables assessment of myocardial performance beyond LVEF. CMR-derived myocardial stroke work is a novel method allowing non-invasive assessment of total active myocardial performance, including both constructive and wasted myocardial work. Specifically, changes in LV stroke work have been shown to carry important prognostic information following TAVR.

Hypothesis The hypothesis is that SEV result in superior valvular hemodynamics (more pronounced during exercise) and exercise capacity relative to BEV. Furthermore, the hypothesis is that stress CMR will be able to demonstrate differences in these hemodynamic parameters. CMR will also provide refined assessment of paravalvular leak and its impact on ventricular function and on clinical outcomes.