Predicting Left Ventricular Outflow Tract Obstruction Before TMVR

Multiphase assessment of the neo left ventricular outflow tract (neo-LVOT) may be superior to end-systolic estimates to determine the risk for LVOT obstruction (LVOTO) with transcatheter mitral valve replacement (TMVR), according to study results published in JACC Cardiovascular Interventions.

In this retrospective analysis, the data of patients who screen-failed for LVOTO concerns (n=33) and the data of patients who were treated with contrast-enhanced dynamic computed tomography (CT; n=29) between March 2015, and July 2017 were examined. In particular, researchers conducted an analysis of the predicted neo-LVOT areas at end systole and assessed multi- and early-systolic phases.

End systole was defined as the cardiac phase of aortic valve closure (at 30% or 40%), which was determined visually from the electrocardiogram (ECG)-gated CT. Neo-LVOT areas were computed throughout the systolic interval, at approximately 10% to 40% in 10% increments. The minimum neo-LVOT area was then computed for a temporal average across the systolic phases. Using the multiphase assessment, one-third of patients who previously screen-failed for LVOTO risk with dynamic CT would now be eligible for enrollment (33.3%). Using the early systolic assessment, an additional 21.2% of these patients would now be eligible for enrollment. There were no clinical observations of LVOTO 30 days postprocedure, despite the assumed risk based on end-systolic estimates.

This study was limited by its small sample size. The results  indicate that the use of a physiologic assessment of LVOTO with early systolic neo-LVOT may allow for a better estimation of post-implant LVOTO. A total of 54.5% of patients in this study who previously screen failed for LVOTO would be eligible for treatment with neo-LVOT.

“We believe there is potential for this screening method to become the new standard of care for predicting risk [for] LVOTO in patients being evaluated for TMVR,” the researchers concluded. “We believe that, as more device sizes become available, the combined impact of early systolic prediction of LVOTO and increased annular size coverage will result in substantially more patients screened being anatomically suitable for TMVR, allowing for a much broader treatment population.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Meduri CU, Reardon MJ, Lim S, et al. Novel multiphase assessment for predicting left ventricular outflow tract obstruction before transcatheter mitral valve replacement. [published online October 11, 2019]. JACC Cardiovasc Interv. doi:10.1016/j.jcin.2019.06.015