Predicting Final Valve Position After TAVR: Different Devices, Different Success

SAN FRANCISCO, CA—Two new pilot studies addressing transcatheter valve orientation during deployment and future coronary access presented at TCT 2019 provide mixed results, with one study suggesting the final orientation of the valve is unpredictable and another showing the valve commissures could be aligned during initial valve deployment to avoid obstructing the coronary arteries.

Gilbert Tang, MD, MSc, MBA (Mount Sinai Health System, New York, NY), who has previously published data on attempts to reduce the severity of overlap of the self-expanding Evolut R and Evolut PRO (Medtronic) transcatheter heart valve commissures with the coronary orifices, reported that despite crimping the Sapien 3 valve (Edwards Lifesciences) at different orientations prior to the procedure, severe overlap with one or both coronary arteries was observed in more than 30% of patients.

In the second study, which was part of a combined effort between Tang’s group and researchers led by Andreas Fuchs, MD, PhD, and Ole De Backer, MD, PhD (The Heart Center/Rigshospitalet, Copenhagen, Denmark), aligning the commissural tab of the Acurate Neo (Boston Scientific) transcatheter heart valve at the center back/inner curve of the aortic root during deployment reduced the occurrence of severe commissural overlap to less than 15%.

As TAVR moves into younger, lower-risk patients, Tang said, there is an onus on interventional cardiologists and surgeons to leave as good a result as possible so that future operators can access the coronary arteries should the need arise. “We’re the ones putting the valve in,” he told TCTMD. “We have ownership. TAVR is now indicated for all-risk patients in the United States, and we should try to achieve an optimal result for patients as much as possible so that down the road we minimize the risk of needing open-heart surgery.”

Sapien 3 and Acurate Neo: Aligning the Commissures

Like in his group’s initial study of the Evolut R/PRO valves, Tang said these latest investigations were an attempt to evaluate how the initial deployment orientation of the Sapien 3 and Acurate Neo valves affects their final position, specifically the relationship of the devices’ commissures to the coronary arteries.      

“The nice thing about the [Acurate] valve is that when it deploys, where you orient the commissures at the start is where the commissures end up,” said Tang during the moderated session where he presented the results of both pilot studies. “The final orientation matches where we start before the valve is deployed. When we do the CT co-registration, it’s quite remarkable to see the impact depends on how the valve was initially aligned. If the tab is in the center front, there’s nearly an 80% chance it will overlap with the left main, 62% chance with the right coronary artery, or an 86% chance it overlaps with one or both coronary arteries, which is the worst-case scenario.”

To assess the device orientation after TAVR without exposing patients to additional radiation and contrast with CT, the researchers recorded aortogram images and the final position of the valves during the procedure. They co-registered the orientation of the valve with the pre-TAVR CT scan using imaging software so that the orientation of the valve commissures and proximity to the coronary arteries could be determined. The technique to assess final valve orientation has been validated with post-TAVR CT images, said Tang.

The study with the Acurate Neo valve, which is approved for use in Europe but not available in the United States, included 100 patients. The commissural tab during the initial deployment was based on its alignment with the aortic root and categorized as center back, inner curve, outer curve, or center front and matched with the final valve orientation. Although the valve orientation was relatively evenly distributed, orienting the tab commissure to center back/inner curve resulted in lowest rates of commissure overlap with the left main, right coronary, at least one coronary artery, or with both coronary arteries.   

The Sapien 3 study included 267 patients undergoing TAVR at two centers between 2018 and 2019. Of these patients, 28.1% had one neo-commissure crimped at “12 o’clock” (ie, aligned with the Edwards logo on the Commander delivery system), 31.3% at 9 o’clock (90 degrees counterclockwise to the logo), 33.3% at 6 o’clock, and 6.9% at 3 o’clock. The goal of the study was to investigate the feasibility of crimping Sapien 3 at specific orientations to reduce neo-commissural overlap with the coronary arteries. In other words, said Tang, the goal was to assess which orientation would result a coronary-access-friendly position for future interventions, such as PCI for atherosclerotic CAD or redo TAVR.   

“With the Commander system, the Edwards logo faces up, and that’s how you’re supposed to deploy the valve,” said Tang. “Basically, when we map the valve before we crimp, we put the valve with one commissure at either 12, 3, 6, or 9 o’clock. Because of the mathematical relationship among commissures, this essentially covers all the possibilities of valve orientation.”

Regardless of where the valve was crimped prior to deployment, severe overlap with the left main, right coronary, or one or both coronary arteries was documented. Overall, 39% of patients treated had overlap of the left main artery, 38.2% of the right coronary artery, and 51.3% with one or both coronary arteries. There was no significant differences in overlap among patients with the Sapien 3 valve crimped at 12, 3, 6, and 9 o’clock.

“It was pretty much random,” said Tang, referring to the final valve orientation. “Despite our best efforts to try to intentionally orient the valve in a selected way, because of the way the delivery system works there is really no way to predict where the commissures will end up. This might have an impact on redo TAVRs and coronary access in the future.”

Commissure Alignment Allows for Leaflet Splitting

To TCTMD, Tang said that while Sapien 3 has a low profile, more than 20% of patients treated with the valve can’t undergo repeat TAVR because of concerns about coronary obstruction. As TAVR is moving into younger, lower-risk patients, the potential for a second procedure is a real possibility, he noted.

“So what commissure alignment allows you to do, which you can’t do consistently with Sapien 3, is the BASILICA technique,” he said. “If the commissures are positioned randomly, and one of them ends up facing the coronary arteries, you can’t do the BASILICA procedure to split the leaflets to restore or improve coronary flow if you were to do a second TAVR. That’s an important issue to think about. If you have a valve with the commissures aligned, at least you can perform BASILICA or a leaflet splitting technique to avoid coronary obstruction. Whether that works or not is a different discussion because it’s still experimental.”

While the Acurate Neo fared well in this particular analysis, addressing commissure alignment and future coronary access, it did not shine as hoped in the SCOPE I trial, which also was presented at TCT. In this head-to-head comparisons of Acurate Neo versus Sapien 3, investigators reported that the former did not meet the prespecified criteria for noninferiority with respect to the primary endpoint of VARC-2 safety and clinical efficacy criteria.