Myocardial work assessment in severe aortic stenosis undergoing transcatheter aortic valve replacement

Myocardial work is a novel echocardiographic algorithm that corrects speckle-tracking-derived global longitudinal strain (GLS) for afterload using non-invasive systolic blood pressure as a surrogate for left ventricular systolic pressure (LVSP). Yet, in patients with severe aortic stenosis, non-invasive systolic blood pressure does not equal LVSP.

We evaluated 35 patients with severe aortic stenosis who underwent transcatheter aortic valve replacement (TAVR). Transthoracic echocardiography, including myocardial mechanics, was performed pre- and post-TAVR. We performed simultaneous echocardiographic and cardiac catheterization measurements in 23 of the 35 patients at the time of TAVR. Peak and mean aortic gradients were calculated from echocardiographic and cardiac catheterization data. Peak-to-peak LV-aortic gradient correlated highly with mean LV-aortic gradient (r = 0.96); measured LVSP correlated highly with our novel method of non-invasively estimated LVSP (non-invasive systolic blood pressure cuff + Doppler-derived mean aortic gradient, r = 0.92). GLS improved from pre- to post-TAVR (-14.2% ± 4.3 vs. -15.1% ± 3.2), and myocardial work reduced from corrected pre-TAVR to post-TAVR (global work index: 1856.2 mmHg% ± 704.6 vs. 1534.8 ± 385.0).

We propose that non-invasive assessment of myocardial work can be reliably performed in aortic stenosis by the addition of mean aortic gradient to non-invasive systolic blood pressure. From this analysis, we note the novel and unique finding that GLS can improve as myocardial work reduces post-TAVR in patients with severe aortic stenosis. Both GLS and myocardial work post-TAVR remain below normal values, requiring further studies.