An independent study has confirmed early benefits of transcatheter aortic valve replacement (TAVR) in low-risk surgical patients with severe aortic stenosis.

Results from a German trial that compared TAVR with surgical aortic valve replacement (SAVR) showed that at one year TAVR was found to bring no increased risks and was associated with substantial decreased rates of death or stroke.

The DEDICATE-DZHK6 trial, reported at ACC 2024 and in the NEJM (link here), compared TAVR vs. SAVR in 1,414 patients with severe aortic stenosis who were at low or intermediate surgical risk who underwent valve replacement procedures at 38 centres in Germany.

All patients enrolled in the trial were eligible for either TAVR or SAVR and had similar characteristics in terms of the severity of aortic stenosis and a similar balance of risks and benefits expected with either type of procedure.

Patients with bicuspid valves, previous heart surgery or additional coronary or valvular diseases requiring further treatment were excluded. The average age of participants was 74 years and 43% were women.

The co-primary safety endpoint was designed to assess whether TAVR was non-inferior to SAVR as indicated by an absolute increase of no more than 1% in the composite rate of death or stroke at one year. The trial met this endpoint, showing the Kaplan–Meier estimate of the primary outcome at one year was 5.4% in the TAVI group and 10.0% in the SAVR group (hazard ratio for death or stroke, 0.53; 95% confidence interval [CI], 0.35 to 0.79; P<0.001 for noninferiority).

The incidence of death from any cause was 2.6% in the TAVI group and 6.2% in the SAVR group (hazard ratio, 0.43; 95% CI, 0.24 to 0.73). The incidence of stroke was 2.9% and 4.7%, respectively (hazard ratio, 0.61; 95% CI, 0.35 to 1.06). Procedural complications occurred in 1.5% and 1.0% of patients in the TAVI and SAVR groups, respectively.

The study investigators noted that while guidelines recommend TAVR for older and high risk patients severe aortic stenosis, there are variations in evidence and recommendations when it comes to determining the optimal approach for younger and lower-risk patients.

“We can now provide strong data that in this low-risk patient population, you could very safely offer TAVR vs. SAVR,” said Professor Moritz Seiffert, a cardiologist at Ruhr University Bochum, Germany, and one of the study co-authors.

“TAVR is less invasive; it’s usually performed under local anaesthesia, lasting 30-60 minutes, and the convalescence is shorter than with open chest surgery. [These findings offer] a strong argument toward catheter-based treatment, at least for the one-year timeframe of this study, in these patients,”  he said.

Professor Seiffert noted that although the study aimed to test TAVR for non-inferiority, the magnitude of the difference had surprised the investigators.

“Valve prosthesis selection based on individual patients’ anatomical and medical considerations may have played a role. In addition, the COVID-19 pandemic might have amplified the surgical risk. In fact, the relative difference was comparable to previous studies, but the overall higher event rates and larger patient population may have led to these significant results,” he said.

The trial provided a unique perspective, he believed, because it was completely industry independent, not focused on one particular device, and thus compared a catheter-based strategy to a surgical strategy overall.

“What it really adds to previous trials is that it mirrors clinical routine … That makes it more applicable and aligned with the types of decisions physicians are making in their daily medical work,” he said.

The study investigators now plan to further investigate some factors that may have contributed to the substantially reduced risk in the TAVR group, including the relatively high proportion of females in the study group. They will also examine whether certain subgroups appear to derive specific risks or benefits from one approach or the other, and to follow up outcomes for five years.

An accompanying commentary in NEJM (link here) cautioned that the early benefits seen in the trial had to be weighed against the lack of data on longer-term outcomes in low risk TAVR patients, especially as many were relatively young.

“The long-term durability of TAVI devices (10 years and beyond) is still not well understood and will require long-term follow up to understand how TAVI valves compare with SAVR valves,” they wrote.

“We also do not know the most appropriate techniques for replacing a failed TAVI valve. Given the potentially increased risk with TAVI explant surgery, it will be important to understand how best to select the patient who may be a candidate for multiple TAVI procedures over their lifetime and to understand the appropriate TAVI platform for the index and subsequent TAVI procedures.

The study was funded by German Center for Cardiovascular Research with financial support by the German Heart Foundation.