What leads to device failure after TAVI for bicuspid aortic valve stenosis?

Among patients with bicuspid aortic valve (BAV) stenosis, the presence of excessive leaflet calcification plus calcified raphe alongside BAV (EC-BAV) significantly aggravates the risk of device failure following transcatheter aortic valve implantation (TAVI), according to a recent study.

“This study highlights the importance of meticulous computed tomography assessment of BAV morphology. Moreover, it suggests that TAVI would be the acceptable treatment for patients with favourable BAV anatomy,” the researchers said.

“In contrast, EC-BAV with small annulus should be treated with surgery unless the surgical risk is high or inhibitive,” they added.

The data, obtained from an analysis of 187 BAV patients (mean age 77 years, 38.0 percent women), showed that EC-BAV increased the likelihood of device failure by more than 16 times (odds ratio [OR], 16.7, 95 percent confidence interval [CI], 1.99–39.6). Meanwhile, having a smaller-than-optimal transcatheter heart valve (THV) worsened such risk by over four times (OR, 4.41, 95 percent CI, 1.43–13.6). These estimates were calculated using Cox regression analysis. [Am J Cardiol 2022;doi:10.1016/j.amjcard.2022.04.037]

Aside from these statistically determined risk factors, researchers noted significant characteristic differences between patients with vs without device failure. For instance, preprocedural peak aortic velocity (4.7 vs 4.3 m/s; p=0.002) and mean pressure gradient (54.2 vs 47.2 mm Hg; p=0.015) were significantly elevated in patients who eventually experienced device failure. Calcified raphe (83.8 percent vs 58 percent; p=0.004) and EC-BAV (81.1 percent vs 38.0 percent; p<0.001) were likewise significantly more common among those with device failure.

Conversely, device failure occurred significantly more frequently among patients with vs without EC-BAV (34.5 percent vs 7.0 percent; p<0.001).

“EC-BAV morphology and small aortic annulus requiring small THV were significantly associated with device failure,” the researchers said.

“In patients without EC-BAV, the incidence of device failure appeared to be acceptable, whereas 91.7 percent, 31.6 percent, and 23.3 percent of device failures were observed in those with EC-BAV who were using SAPIEN 3/Ultra 23-, 26-, and 29-mm, [respectively],” they added.

The present study enrolled 187 BAV patients who saw notable haemodynamic improvements after TAVI, as demonstrated by a significant decrease in peak aortic velocity and mean pressure gradient. Moderate or severe paravalvular leakage after TAVI occurred in 14.5 percent. Assessments were conducted using multidetector computed tomography and coronary angiography. Of the participants, 37 (19.8 percent) developed device failure.

Notable study limitations included its observational and retrospective design, lack of representation for the 20-mm SAPIEN 3 device, and the semiquantitative manner in which leaflet calcification was assessed. These factors made the conclusions of the study hypothesis-generating, and its external validity should be confirmed in future studies.