ACS After TAVR a Unique Condition With Poor Prognosis

Acute coronary syndromes that occur after TAVR differ from ACS seen in the broader population and carry very high short- and long-term mortality risks, new data show.

The differences in clinical features, management, and outcomes are likely related to the older age, higher comorbidity burden, and routine use of antithrombotic therapy in the TAVR population, researchers led by Laurent Faroux, MD (Quebec Heart and Lung Institute, Laval University, Canada), say.

Of note, only a small proportion of patients presented with STEMI (8.1%) and rates of invasive coronary angiography and PCI were lower than would be seen in a typical ACS population. STEMI was associated with increased risks of all-cause death and MACCE (all-cause death, MI, or stroke), whereas PCI was tied to a lower mortality risk.

“These results should inform future studies to improve both the prevention and management of ACS post-TAVR,” the authors write in their paper published in the February 2020 issue of Circulation: Cardiovascular Interventions.

Little Data on Post-TAVR Coronary Events

Roughly half of TAVR candidates have CAD in addition to aortic stenosis, and about half of those with evident disease undergo PCI before their valve replacement. But, Faroux et al say, there are few studies specifically exploring coronary events after TAVR.

“In addition to the clinical characteristics of most TAVR candidates (elderly patients with high comorbidity burden), the underlying disease (aortic stenosis, frequently associated with significant left ventricular changes), and the possibility of several mechanisms leading to an ACS post-TAVR (atherothrombotic, impaired coronary flow, leaflet thrombosis, late valve migration, hypersensitivity reaction against the device) make the ACS post-TAVR population unique,” they write.

Senior author Josep Rodés-Cabau, MD (Quebec Heart and Lung Institute, Laval University), noted, too, that ACS will likely become a more frequent issue after TAVR as the procedure moves into lower-risk patients. These patients will live longer than those who underwent TAVR early on and have a greater opportunity to have coronary events.

The current study, encompassing 13 centers, included 270 patients (mean age 79 years; 56.3% men) who presented with ACS after TAVR (at a median of 12 months after the procedure). Patients presented with NSTEMI type 2 (31.9%), NSTEMI type 1 (31.5%), unstable angina (28.5%), and STEMI (8.1%). At the time of presentation, 37.0% of patients were on dual antiplatelet therapy, 12.6% were on oral anticoagulation, and 14.4% were on a combination of antiplatelet and anticoagulant therapy.

Overall, 60.4% of patients underwent invasive coronary angiography and 35.9% underwent PCI. At least one significant coronary lesion was found in 85.3% of patients who had an angiogram. Of that group, 57.6% had new lesions that either were not present or were not severe at the time of the pre-TAVR workup, 30.9% had previously identified significant lesions that had been left untreated before TAVR, 10.8% had in-stent restenosis, and 0.7% (one patient) had a coronary embolism related to a sinus of Valsalva thrombosis.

“These findings emphasize the need to determine the ideal management of coronary lesions identified in the workup pre-TAVR,” the authors say.

Outcomes after ACS were poor. During the initial hospitalization, 10.0% of patients died, 1.9% had a stroke, 22.6% had heart failure, and 17.0% had acute kidney injury. After a median follow-up of 17 months, 43.0% of patients had died, with a 3-year rate of 49.8%. Rates of stroke, MI, and MACCE were 4.1%, 15.2%, and 52.6%, respectively.

“The prognosis of these patients is poor, and I think it’s something that should inform probably more studies in this specific field,” Rodés-Cabau said.

Hard to Draw Firm Conclusions

Commenting for TCTMD, David Hildick-Smith, MD (Brighton and Sussex University Hospitals, Brighton, England), said it was difficult to tease out any definitive conclusions from the study because of the unique nature of the post-TAVR population, including the high mortality rate, the distribution of presentations with a small proportion of STEMIs, and the low use of invasive investigations or procedures. It seems likely, he said, that many of the events were identified in the context of some other illness, like pneumonia or kidney failure, and that the patients were already frail before the acute coronary event.

“It’s welcome data, but I think the very high mortality shows you that these were just patients reaching the end of their lives anyway and the management of their acute coronary syndrome probably wasn’t that instrumental in influencing their survival or not,” Hildick-Smith said. “I think it’s quite a hard study to draw firm conclusions from.”

He said he would have liked to see more information on coronary access issues, which were reported for 2.5% of coronary angiographies (four patients) and 2.1% of PCIs (two patients). All of the issues were in patients who underwent TAVR with a self-expanding CoreValve or Evolut R (both Medtronic). The rates of access issues don’t seem particularly high, and it’s not surprising that all of the cases involved a self-expanding valve, Hildick-Smith said.

“The frame of the Medtronic CoreValve comes above the sinotubular junction and, therefore, in order to access the coronaries you have to go through the lattice of the implanted valve,” he explained. “Whereas with, for example, the Edwards valve, as long as it’s been put in in the correct place, all of the valve is below the sinotubular junction and, therefore, the coronaries are accessible from above.”

Rodés-Cabau urged caution when interpreting potential differences between valves when it comes to coronary access after TAVR, noting that the current study involved few such cases. He acknowledged that “it is possible that some valves are associated with more difficulties,” but said other factors—like the width of the sinus of Valsalva and the height of the coronary arteries—also come into play.

Still, later access to the coronary arteries should be a consideration when performing TAVR, particularly in younger patients, he said. “It’s something definitely that should play a role . . . when you evaluate which valve type you have to implant in a patient with a relatively high likelihood of having a coronary event after TAVR.”

Beyond coronary access issues, the study indicates that there is room for improvement when it comes to managing ACS after TAVR, Rodés-Cabau said. The association between PCI and a lower mortality risk could have been subject to confounders, but the fact that the relationship remained significant after multivariable adjustment suggests that outcomes could be improved if it were performed more frequently in this setting, particularly in patients with STEMI, he said.

“Primary PCI saves lives and is something that should be applied if possible to all patients,” he said. “For me at least, there is clearly room for improvement in this specific subgroup, without any doubt.”