Meticulous Slicing No Better Than Stenting at Axing Feared TAVR Complication

PARIS -- To mitigate the risk of acute coronary obstruction during transcatheter aortic valve replacement (TAVR), chimney stenting and electrosurgical leaflet laceration performed similarly -- albeit each with its unique pros and cons -- in the first formal head-to-head comparison of the two techniques.

No significant difference in 1-year major adverse cardiovascular events (MACE) emerged between real-world recipients of chimney stenting (18.7%) and those undergoing BASILICA (bioprosthetic or native aortic scallop intentional laceration to prevent iatrogenic coronary artery obstruction; 19.9%, log-rank P=0.848), Antonio Mangieri, MD, of Humanitas Research Hospital in Milan, reported at the EuroPCR meeting here.

Whereas the individual endpoint components of all-cause death, myocardial infarction, stroke, and target lesion revascularization each supported the similarities in performance, there was a trend for more cardiovascular deaths in the chimney group (6.7% vs 1.3%, log-rank P=0.168), Mangieri noted.

As for VARC-3 periprocedural complications, there were signals of more paravalvular leak and need for permanent pacemaker with the chimney technique, as well as numerical excess of postprocedural acute kidney injury due to the greater amount of contrast used.

Coronary obstruction is a rare but deadly complication of TAVR, and factors have been identified that put people at high clinical and anatomic risk.

Operators may opt for a preventive measure such as chimney stenting. Mangieri said this involves leaving a stent parked in a coronary artery and protruding into the aorta; after the transcatheter heart valve is deployed, the stent is deployed as well, leaving the so-called "chimney" sticking out to maintain the patency of the coronary artery.

An alternative to chimney stenting is BASILICA leaflet splitting using focused radiofrequency energy. This technique is known for being technically demanding, however, and there are concerns that it may result in embolic complications related to leaflet laceration. Indeed, Mangieri remarked on the greater use of cerebral protection devices when BASILICA was employed.

What's more, he reported, the electrosurgical leaflet laceration technique was associated with a worse rate of freedom from bailout coronary stenting (98.5% vs 91.8%, P=0.052) -- among experienced BASILICA operators, notably -- despite being technically just as successful in preventing strictly clinically relevant coronary obstruction.

It may appear that the skills needed to get BASILICA right are not worth the hassle for many operators.

"I'm a chimney operator because it's easier," Mangieri said at a press conference. He cited the requirements of more vascular access and echocardiographic guidance to correctly split the leaflets. Moreover, cases of sinus sequestration may still arise and cannot be managed by BASILICA, he said.

Session panelist Alain Cribier, MD, of Hopital Charles Nicolle CHU Rouen in France, nevertheless advocated for more BASILICA-trained operators as he asked the rhetorical question, amid laughter in the room, of how one is supposed to reaccess the coronary arteries in the long term after chimney stenting.

In any case, there are various technical aspects of chimney stenting -- which stents to use, how long, in which patients, for example -- that still need to be worked out, according to session chair Darren Mylotte, MD, of University Hospitals Galway in Ireland.

Mangieri's observational study included consecutive TAVR patients from 2015 to 2021 at two sets of high-volume hospitals: nine Chimney centers (mostly in Italy) and 12 BASILICA centers (half in Germany, the rest split among other countries).

This translated into 71 people in the chimney group and 97 undergoing BASILICA. Overall, patients averaged 80 years of age and 64% were women.

Mangieri reported that there were no large between-group differences at baseline. Exceptions were that the BASILICA group had a greater preponderance of chronic kidney disease (64% vs 48%, P=0.038), whereas the chimney group had more moderate-severe mitral regurgitation (72% vs 32%, P<0.001).

In the chimney stenting arm, the technique was employed in the left main artery in 38% of cases, the ostial right coronary artery in 17%, and both in 45%, according to the presenter.

Meanwhile, 86% of the BASILICA group had two leaflets lacerated, and the rest only one.

A randomized study would be needed to draw definite conclusions about the superiority of one technique over the other, Mangieri acknowledged.

Yet the task of finding centers, equally experienced in chimney stenting and BASILICA, and forcing them to randomize patients for a proper trial, would be highly difficult, according to press conference moderator William Wijns, MD, MPH, of National University of Ireland in Galway.

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