Meta-analysis Raises ‘Red Flag’ on TAVR in Low-Risk Patients

A new study cautions against expanding the use of TAVR into lower-risk patients, demonstrating that the risk of mortality is higher at 2 years after the transcatheter approach versus surgery.

Expanding TAVR into patients at low surgical risk may carry significant hazards, say researchers, and until more is known, surgical aortic valve replacement (SAVR) should be prioritized as first-line therapy.

“SAVR should firmly remain the treatment of choice in low-risk patients until [there is] more evidence on the comparative benefits/risks of TAVR compared to SAVR in this patient group,” lead investigator Guy Witberg, MD (Rabin Medical Center, Petach Tikva, Israel), said in an email.

The meta-analysis, published online February 1, 2018, ahead of print in Catheterization and Cardiovascular Interventions, included six studies published between 2012 and 2017 that enrolled a total of 3,484 patients. Short-term mortality after TAVR and SAVR was similar, but by 2 years the mortality rate was 17.2% for TAVR and 12.7% for SAVR (P = 0.006).

Ted Feldman, MD (Evanston Hospital, Evanston, IL), who commented on the study for TCTMD, said the findings are “provocative,” but limited by the inability to do patient-level matching between TAVR and SAVR groups and to measure confounders that are inherent in registries.

“[The study’s conclusion] is consistent with all of our guidelines for low-risk patients and it is based on the uncertainty of the balance between the advantages of a highly-established surgical procedure compared to a less-mature catheter procedure,” Feldman said. “This meta-analysis may or may not shine new light. I think what it does, though, is highlight the need for the randomized trials that are ongoing.”

Currently, three such trials are underway in the low-risk patient population: PARTNER 3, Medtronic Transcatheter Aortic Valve Replacement in Low Risk Patients, and NOTION 2. According to Witberg and colleagues, all three are expected to complete data collection for their primary endpoints over the next 2 years, and to have a combined sample size of approximately 3,500 patients.

Witberg said the conclusion of the meta-analysis could potentially be changed by the trials, adding, “I, as well as the whole of the interventional cardiology community, am eagerly awaiting their results within the next 18 months.”

Periprocedural Complications and Red Flags

On a positive note, the meta-analysis also found that the risk/benefit profile for periprocedural complications in low-risk patients is similar to that seen in the overall TAVR population, including less acute kidney injury and bleeding counterbalanced by an increase in pacemaker implantation and vascular complications.

Although it was not studied in the meta-analysis, Feldman noted that new-onset A-fib is a potential periprocedural complication that can have a critical impact on later outcomes after AVR.

“In every TAVR experience, [new-onset A-fib] has been shown to be much lower than surgical AVR, and this is another of the counterbalances that are so crucial in a direct randomized trial with longer-term follow-up,” he added.

To TCTMD, Witberg said he agreed that the issue of new A-fib is important to take into account when considering the balance of benefits and risks, especially in younger TAVR candidates. But he also noted that at least one recent meta-analysis of non-high-risk patients found no significant difference in the occurrence of new A-fib between TAVR and SAVR (RR 0.31; 95% CI 0.27-0.36).

Overall, Witberg and colleagues say that given the trend to continue expanding TAVR into lower-risk patients, “we think that our results should raise a ‘red flag’ to the interventional cardiology community and serve as a reminder that, at least for now, this practice is not supported by clinical data, and that great care and a thorough evaluation process should be undertaken before referring low-surgical-risk patients to TAVR.”