Patients with severe aortic stenosis and predominantly noncalcific remodeling of the aortic valve (AV) were found to have worse myocardial structural alterations when evaluated for TAVR using cardiac computed tomography angiogram (CTA) and this is associated with increased myocardial fibrosis or worse filling pressures, according to findings in a research letter published May 21 in JACC: Cardiovascular Imaging.

Davide Margonato, MD, et al., conducted a proof-of-concept study to examine the association between in vivo AV tissue composition characteristics on comprehensive CTA and myocardial function and structural changes in severe AS, in particular myocardial fibrosis assessed by myocardial extracellular volume (M-ECV). They randomly selected 91 patients from their database of 280 patients who underwent pre-TAVR imaging assessment between November 2020 and June 2022.

Within the study cohort there was equal distribution within the 19-month study period, and patients underwent clinical evaluation, transthoracic echocardiography and pre-TAVR cardiac CTA using a third-generation dual-course CT system. Their mean age was 83 years, half were women, 55% had atrial fibrillation and 64% were NYHA functional class III or IV with a median LVEF of 57%.

The median AV area was 0.76 cm2 and a third had low-flow gradient AS. Median AV calcium volume was 344 mm3 and noncalcific volume was 340 mm3 with a median noncalcific to calcific (NC/C) volume ratio of 0.96.

When dividing the study cohort by NC/C ratio, results showed that patients with a higher ratio had higher left ventricular (LV) filling pressures while no differences were observed in LVEF. Additionally, they had increased relative wall thickness, smaller AV area and larger left atrium indexed volumes. Notably, patients with a high NC/C ratio also had higher M-ECV. On multivariable analysis, an NC/C above the median was independently associated with elevated M-ECV, even after adjusting for age, gender and AV area (odds ratio, 3.69; p=0.005).

The authors write that the findings confirm the importance of quantification of different AV tissue characteristics and that they provide novel mechanistic insights and explain the short-term adverse outcomes of noncalcific AV. They add that validation of these findings from their single-center, single-vendor study requires validation by a larger cohort.