Beware High-Risk TAVI in Patients With Low-Lying Coronaries

For patients with symptomatic severe aortic stenosis and anatomical features that could result in coronary obstruction, the best option in some cases can be surgery, according to a comprehensive review of the potential risks of TAVI.

While it’s possible to protect the coronary ostia, sometimes with a stent and sometimes with leaflet modification, it might be in patients’ best interest if the heart team goes with surgical aortic valve replacement.  

“In young, low-risk patients, physicians should strongly consider a low-risk SAVR over a high-risk TAVI,” said Gilbert Tang, MD, MSc, MBA (Mount Sinai Health System, New York), who has highlighted the importance of commissural alignment to facilitate future coronary access.

Tang, who spoke on the risks associated with low-lying coronary ostia at the American Association for Thoracic Surgery (AATS) 2023 meeting this past weekend, told TCTMD the incidence of coronary obstruction with TAVI in native aortic stenosis is reported to be around 0.6%, but that the complication carries a very high risk of mortality if it occurs (approximately 50%). When valve-in-valve procedures are performed, the incidence of obstruction is significantly higher, at around 2% to 3%.

Tang said that the presence of low-lying coronary arteries is “not a contraindication” for TAVI, though does raise questions about whether future coronary access will be straightforward, or even possible.

“Unlike with surgery, you’ll have the native leaflet in the way, and the frame in the way,” he said. “Even with the shorter, balloon-expandable valve, you’re going have to put a catheter all the way down into the coronary arteries. With everybody wanting to implant the valve higher to avoid the need for a permanent pacemaker, it’s going to be a challenge to get a catheter into those with lower coronary arteries. That’s typically an issue with the left main rather than the right. The right coronary artery is typically higher than the left coronary.”

Delayed Obstruction Also Possible

While coronary obstruction is recognized as an acute complication resulting from TAVI or valve-in-valve procedures, obstruction can manifest late, sometimes days or months after the transcatheter procedure. In one large, multicenter registry, delayed coronary obstruction occurred in 0.22% of more than 17,000 TAVI cases and was most likely to develop in the first 24 hours after TAVI. There were complications, however, that arose beyond 60 days.

The risk of coronary obstruction can be predicted on preprocedural CT imaging based on dimensions of the aortic root, which takes into account factors beyond the location of the coronary arteries. Tang said that physicians should have a low threshold to protect the coronary ostia if worried about obstruction. “The bottom line is that if you are concerned about it, it’s very easy to protect,” he said. Preventive coronary wiring and stenting across the coronary ostia “can buy you a lifeline to be able to manage the situation if it does obstruct.”

While such a strategy can prevent obstruction, access for future interventions can still be challenging, with both a transcatheter valve frame and coronary stent in the way.

“That’s why we think that in patients at low surgical risk, where you have to place a [preventive] coronary stent, not to mention the need for dual antiplatelet therapy, it’s not a trivial endeavor,” said Tang. “For young people at low surgical risk, if they have low coronary arteries at risk for coronary obstruction, and if you’re considering protecting the left main, maybe surgical valve replacement with a root enlargement might be a better solution.”

Tang pointed out that many patients with low-lying coronary arteries also have a small aortic root relative to the coronary artery, which compounds things if the transcatheter valve fails in 8 to 10 years. “You really don’t have an option for redo TAVR,” said Tang. “You don’t have enough space. Not to mention that you have a potential coronary stent sticking into the ascending aorta. It really makes it unfeasible to do any future intervention.” In addition, TAVI explantation in patients with a preemptive stent in the left coronary artery is a risky proposition.

While there is an up-front cost of surgery, there are potential long-term consequences of TAVI in patients with coronary anatomy at risk for obstruction, said Tang. A complex TAVI procedure may be justified in patients at high or intermediate risk for surgery, but surgery might be a better option for the low-risk set.  

The BASILICA technique, which involves lacerating the bioprosthetic or native aortic leaflet, and ShortCut (Pi-Cardia), a dedicated transcatheter leaflet-splitting device, are gaining traction to prevent to coronary obstruction. But the BASILICA procedure is infrequently performed given the low incidence of coronary obstruction with the next-generation valves and requires specialized equipment, said Tang, noting some of the downsides. If the commissures aren’t properly aligned, there might still be a risk of coronary obstruction with the valve frame.