CoreValve Prosthesis Depth: What is the Optimal Measurement Target?

A major drawback of the transcatheter aortic valve replacement (TAVR) procedure using the self-expandable Medtronic CoreValve (MCV) prosthesis is the high incidence of conduction disturbances and the need for postprocedural permanent pacemaker (PPM) implantation. The depth of prosthesis implantation may be an important contributing factor. The study aim was to determine the relationship between angiographic measurements of the MCV prosthesis depth and the occurrence of new conduction disturbances and need for PPM after TAVR.

A retrospective analysis was conducted of 157 consecutive patients who had undergone TAVR procedures with the MCV between 2009 and 2013. Patients with pre-existing pacemakers (n = 27) were excluded. Prosthesis depth was defined as the angiographic distance from the lowest part of the prosthesis to the base of the non-coronary cusp (NCcD) and the base of the left coronary cusp (LCcD).

A 26 mm MCV was implanted in 50% of patients, and a 29 mm MCV in 38%. The rate of new ≥2nd degree atrioventricular block (AVB) after TAVR was 5%, and the incidence of new left ventricular bundle branch block (LBBB) was 23%. PPMs were implanted in 13 patients (10%) within 30 days after the procedure. Freedom from new ≥2nd degree AVB, LBBB and the need for PPM after TAVR was significantly higher among patients with NCcD <6 mm or LCcD <8 mm (90% and 89%, respectively) compared to patients with NCcD ≥6 mm or LCcD ≥8 mm (53% and 54%, respectively) (p <0.0001).

Prosthesis depth, measured relative to either the NCcD or LCcD, strongly predicted the occurrence of conduction disturbances and the need for PPM following TAVR with the MCV prosthesis.