Severe mitral stenosis tied to worse outcomes post-TAVR

About 3 percent of patients undergoing transcatheter aortic valve replacement (TAVR) also have severe mitral stenosis and are at a greater risk of long-term adverse events, researchers reported in JACC: Cardiovascular Interventions.

Lead author Lee Joseph, MD, MS, and colleagues analyzed in-hospital outcomes of 44,755 patients from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapies registry, as well as one-year outcomes of 31,453 whose claims data was available through CMS. They sought to determine the prevalence of mitral stenosis (MS) and its association with mortality and adverse events among TAVR recipients.

Nonsevere MS was defined as a mitral valve area between 1.51 and 4 sq. cm, while severe stenosis included mitral valve areas below 1.5 sq. cm.

Among the study cohort—mean age 82; 52 percent male—11.6 percent had MS but only 2.7 percent had severe MS. But individuals with severe MS had higher in-hospital mortality rates (5.6 percent versus 4.1 percent for no MS). They were also at a covariate-adjusted 20 percent increased risk of meeting the primary composite endpoint of death, stroke, heart failure-related hospitalization and mitral valve intervention within one year of TAVR.

“The greater risk for adverse composite outcomes at one year in the severe MS group was mostly driven by reintervention for mitral valve disease, mortality, and heart failure-related hospitalization,” the authors wrote. “These data highlight that patients with combined severe aortic stenosis and MS being considered for TAVR should be regarded as high-risk patients. Additional periprocedural measures, particularly, aggressive heart failure management and weighing the benefits of TAVR alone versus combined aortic and mitral valve intervention, should be considered in these patients.”

Lee and colleagues found the one-year risks of heart failure-related hospitalization and mortality were increased by 30 and 20 percent, respectively, in the severe MS cohort versus those with no MS.

Due to the advanced age of the study group, the authors hypothesized most of the cases of MS were degenerative. They also noted rates of post-TAVR aortic regurgitation were higher in the severe MS group, which suggests paravalvular leak as a potential reason for the higher risk of adverse events.

However, they acknowledged additional studies are needed to better uncover these associations and investigate whether transcatheter mitral valve interventions are useful in this patient population.

“With advances in transcatheter valve therapies, transcatheter aortic and mitral valve implantation may become a viable alternative to conventional open-heart surgery in selected high-risk patients with concomitant severe aortic stenosis and MS,” Joseph et al. wrote. “The findings of this study should not persuade against TAVR in patients with concomitant severe aortic stenosis and MS but it illustrates the increased risk of late adverse outcomes in patients with severe MS and underscores the importance of appropriate risk stratification, periprocedural management, and the possibility of additional procedural consideration, such as mitral valve intervention.”