Repositionable, self-expanding transcatheter aortic valve replacement (TAVR) using a patient-specific, minimizing depth according to membranous septum (MIDAS) approach to device implantation achieved very low and predictable rates of permanent pacemaker implantation (PPMI) that were significantly lower than those previously reported using the self-expanding TAVR, according to study results published in JACC: Cardiovascular Interventions.

Limited data exist on how to minimize the high risk for PPMI that accompanies self-expanding TAVR. This study, conducted at New York University Langone Health, was designed to investigate risk minimization using contemporary repositionable self-expanding TAVR. The analysis included 248 consecutive patients with severe aortic stenosis, with all patients undergoing TAVR with the repositionable self-expanding TAVR, using a standard approach to device implantation under conscious sedation. Researchers used a detailed analysis of factors contributing to PPMI to generate an anatomically guided MIDAS approach to implantation that achieves a prerelease depth in relation to the noncoronary cusp of less than the length of the membranous septum.

The overall rate of PPMI was 9.7%. Multivariate analysis including baseline right bundle branch block (RBBB), size of device, and implant depth in relation to length of membranous septum predicted PPMI with c-statistic of 0.81 (95% CI, 0.72-0.9; P <.001).

Compared with the retrospective standard group, the prospective MIDAS group had similar rates of PPMI risk factors: RBBB, 12% vs 14.9% (P =.48); membranous septum length <2 mm, 23% vs 17.7% (P =.26); and use of XL prosthesis, 8% vs 11.3% (P =.36).


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Although investigators observed similar membranous septum lengths in the MIDAS and standard groups, they saw a small but significant between-group difference in device depth (MIDAS device depth, 2.3±1.2 vs mean standard device depth, 3.3±1.8 mm; P <.001), which translated to a dramatic difference in device depth less than membranous septum length (MIDAS group, 79.8% vs standard group, 54.8%; P <.001).

Multivariate analysis showed the only independent predictors of PPMI were implant depth greater than membranous septum length (odds ratio 8.04; 95% CI, 2.58-25.04; P <.001) and Evolut® R 34 XL (odds ratio 4.96; 95% CI, 1.68-14.63; P =.004). When researchers prospectively applied the MIDAS approach to a series of 100 consecutive patients, with operators aiming for a device depth less than membranous septum length whenever possible, the new PPMI rate was reduced from 9.7% in the standard cohort to 3% in the MIDAS group (P =.035), and the new left BBB rate was reduced from 25.8% to 9% in the standard vs MIDAS cohorts, respectively (P <.001).

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Although the study included imaging limitations, the study investigators conclude, “Implementing this anatomically based, patient-specific MIDAS-TAVR approach may achieve extremely low and predictable rates of new pacemaker and new LBBB following repositionable self-expanding TAVR that could be at least as low as balloon-expandable TAVR and even as low as SAVR.”

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

Reference

Jilaihawi H, Zhao Z, Du R, et al. Minimizing permanent pacemaker following repositionable self-expanding transcatheter aortic valve replacement [published online August 22, 2019]. JACC Cardiovasc Interv. doi:10.1016/j.jcin.2019.05.056