TAVR Goldilocks - Too High, Too Low, or Just Right

High implantation technique for transcatheter aortic valve replacement (TAVR) reduced conduction system injury but increases the predicted risk of unfavorable coronary access and sinus sequestration with future TAVR-in-TAVR.¹

Transcatheter aortic valve replacement is rapidly becoming the preferred strategy for management of severe aortic stenosis across the risk spectrum, driven both by randomized trial data and patient preferences. But as TAVR is increasingly contemplated for younger patients with lower surgical risk and longer life expectancy, risk mitigation becomes exponentially more important. Nuanced planning and procedural finesse to avoid complications such as conduction system injury or coronary obstruction as well as attention to lifelong management with regards to future coronary access and feasibility for downstream TAVR-in-TAVR take priority.

High implantation technique (HIT) has been described for both the Medtronic self-expanding valves (SEV – Evolut R/PRO/PRO+) and the Edwards balloon-expandable valves (BEV – Sapien 3) with hopes to reduce conduction system injury and need for permanent pacemaker. However, higher-deployed valves increase the risk for sinus sequestration (with indirect coronary obstruction) with future TAVR-in-TAVR and for unfavorable coronary access due to interaction of the sinotubular junction and/or coronary ostia with the TAVR valve frame, commissural posts, sealing skirt, or prosthetic leaflets.

Ochiai and colleagues studied the impact of high implantation technique (HIT) vs conventional implantation technique (CIT) on conduction system injury defined as 30-day new permanent pacemaker implantation (PPI) or new-onset persistent left bundle branch block (NOP LBBB), risk of unfavorable coronary access, and risk of sinus sequestration with future TAVR-in-TAVR. In a single center experience spanning December 2017 to February 2022, they identified patients undergoing TAVR with either HIT or CIT stratified by type of valve (SEV vs BEV). At their center they transitioned from CIT to HIT for both valve platforms at specific timepoints such that most valves implanted historically were with the CIT whereas HIT was used for more recent TAVRs. Post-TAVR computed tomography was used to predict the risk of unfavorable coronary access and sinus sequestration with future TAVR-in-TAVR.

A total of 418 consecutive TAVRs meeting study criteria were included of which 160 received a SEV (CIT: 110, HIT: 50) and 258 received a BEV (CIT: 150, HIT: 108). Indeed, HIT resulted in higher positioned valves for both platforms compared with CIT (SEV: 3.5 +/- 1.2 mm vs 5.4 +/- 2.2 mm, P < 0.001; BEV: 2.6 +/- 0.9 mm vs 4.3 +/- 1.4 mm, P < 0.001).

The impact of implantation technique differed between the valve platforms. For TAVR’s performed with a SEV, the HIT group had lower 30-day PPI rate (0.0% vs 10.8%; P = 0.02) with no statistically significant difference in the NOP LBBB rate (4.2% vs 11.3%; P = 0.22) compared with the CIT group. In contrast, for TAVR’s performed with a BEV, the HIT yielded no difference in 30-day PPI rates (2.0% vs 2.2%; P = 1.00) but lower rates of NOP LBBB (1.1% vs 7.0%; P = 0.047) compared with CIT.

For TAVR’s performed with a SEV, HIT resulted in greater incidence of interference of the valve skirt with 1 or both coronary ostia (22% vs 9.1%; P = 0.03) but lower incidence of interference of a commissural triangle or diamond with 1 or both coronary ostia (26% vs 42.7%; P = 0.04) compare with CIT. Of note, HIT with the SEV also included measures to improve commissural alignment. For TAVR’s performed with a BEV, HIT resulted in similar predicted rates of coronary ostial interference with valve skirt (0.9% vs 0.7%; P = 1.00) and commissural tabs (15.7% vs 15.3%; P = 0.93) compared with CIT. The predicted risk of sinus sequestration with future TAVR-in-TAVR appeared generally to be greater with SEV and with HIT compared with CIT for both valve platforms (SEV: 64% vs 41.8%, P = 0.009); BEV: 17.6% vs 5.3%, P = 0.002).

In this first study to systematically investigate the impact of HIT, the results differed by valve platform. Generally, for both SEVs and BEVs, HIT is associated with lower incidence of new PPM or LBBB. For coronary access, when an Evolut R/PRO/PRO+ valve was implanted with HIT and attention to commissural alignment, there is greater risk of interference with the valve skirt but lower risk of interference with a commissure. In contrast HIT did not modify the risk of coronary interference with valve skirt or commissure with the Sapien 3 valves. Expectedly, the predicted risk of sinus sequestration with future TAVR-in-TAVR appears greater with SEVs and with HIT for both valve platforms. Caveats to these associations include retrospective nature, unclear power to detect differences, single center experience, unvalidated approach to predict risk of coronary access or sinus sequestration, and the switch to HIT for later TAVRs such that there may have also been systematic differences in other aspects of selection, technique, pharmacology, and other unknown key variables.

Clearly, there are trade-offs when selecting both the valve to implant and the technique for implantation. Personalization to match the right patient for the right valve and the right technique will be important. For instance, the approach for a patient with a large root and baseline right bundle branch block should differ for another with a small root, low coronary ostial heights, and normal baseline conduction. One thing is for sure. No longer is it sufficient to simply replace a stenotic valve for a functioning one. Especially for younger, lower risk, and longer living patients, we must take care to personalize the approach to minimize adverse consequences. Yes, the devil is in the details.