麻豆传媒

SAN ANTONIO -- The early experience of patients needing cardiac surgery after transcatheter aortic valve replacement (TAVR) has surgeons raising the alarm about the excess risks of these challenging procedures, based on data from the Society of Thoracic Surgeons (STS).

Nationwide numbers show a "very obvious increase" in post-TAVR surgeries recorded in the STS Adult Cardiac Surgery database from 2012 through March 2023 -- over 5,400 affected individuals during that period -- the frequency of cases accelerating especially after the TAVR low-risk approval in 2019. Aortic valve procedures were most common in general after TAVR, whereas the most frequent non-aortic valve replacement (AVR) procedures were coronary artery bypass grafting (CABG) and mitral replacement surgery, reported Michael Bowdish, MD, of Cedars-Sinai Medical Center in Los Angeles.

Bowdish highlighted the whopping unadjusted operative mortality rate of 15.8% and the 4.5% incidence of permanent strokes after any post-TAVR cardiac surgery.

Notably, STS risk modeling underestimated the mortality risk of patients undergoing cardiac surgery after TAVR. For example, there were 60% more deaths than predicted after CABG, and over 200% more mortalities than expected after mitral valve replacement, he told the audience here at the STS annual meeting.

"SAVR [surgical aortic valve replacement] after TAVR shouldn't be considered simple AVR," he said, suggesting that "referral to centers of excellence is something to think about."

Session discussant Shinichi Fukuhara, MD, of University of Michigan in Ann Arbor, suggested that the factors driving TAVR explants are unfavorable anatomy leading to coronary obstruction, concurrent cardiac pathologies, and endocarditis.

"I'm feeling that the TAVR explant pandemic is starting ... What I saw from this presentation is in line with what we are seeing every day," Fukuhara said.

Bowdish said the STS algorithms may be underperforming because they don't capture frailty, or if there is some inherent risk that is not being accounted for. He mentioned the ongoing debate about whether it is appropriate to call someone who undergoes TAVR and then SAVR a case of isolated AVR. "I'm sure people in the audience have very strong feelings one way or another," he said.

"Personally I don't think it's right to penalize [the surgeons] if the model isn't performing ... The first step is to understand that," but more data are "obviously" needed, Bowdish said.

"This is only the tip of the iceberg and beginning of a pandemic," agreed Marc Ruel, MD, MPH, of University of Ottawa, Ontario. He explained his nightmare situation: a patient who has a bioprosthetic valve, then a valve-in-valve procedure, then the transcatheter valve fails due to structural valve deterioration and the patient comes back 6 or 7 years later to explant everything.

Fukuhara said a few weeks ago he had explanted five TAVR valves in one week. Just last Friday night, he said, he explanted the 101st TAVR valve for his program at Michigan. One time he explanted five prosthetic valves from one patient: two TAVR valves, one surgical prosthetic valve, one transcatheter mitral valve replacement valve, and one surgical mitral valve all from the same individual.

"That is a horrible operation," Ruel stressed. "Every time you send someone who could have easy AVR and they valve-in-valve ... We need to have more data on this when we make that decision."

Bowdish said that patients in the STS database were split into two groups: those undergoing non-AVR cardiac surgery (n=2,485) and the SAVR cohort (n=2,972). His group excluded patients who underwent emergent SAVR or repair of a dissection or root rupture during a concomitant TAVR, so emergencies in the cath lab were not counted in his report.

The cohort had a median age of 73 years, with 38.6% women. One in three participants had aortic valve stenosis. Nearly 90% of procedures were classified as elective or urgent. The non-AVR cardiac surgeries included aortic or root procedures, CABG, and mitral operations among other procedures.

The study showed that predictors of mortality from SAVR after TAVR were emergency surgery, dialysis, CABG, mitral valve surgery, and aorta or root replacement, according to a risk-adjusted model.

Bowdish noted that TAVR explant and SAVR required aortic sinus or root procedures in 28.8% of cases, with full root done in 13.4%.

In contrast, the specific type of TAVR valve previously placed was not predictive of mortality -- though this may be due to the missing data in the dataset, the investigator cautioned.

The STS database in general could not provide much granular information, Bowdish said, such as whether the patients would have been good surgical candidates before they got TAVR. The timing relationship between TAVR and cardiac surgery was also unknown due to a lack of linkage between STS and TVT data.

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