March 29, 2020
UK-TAVI Trial Compares TAVR and Open Surgery in Broad, Real-World Patient Population
March 29, 2020—The American College of Cardiology (ACC) announced that William D. Toff, MD, presented 1-year findings from the United Kingdom Transcatheter Aortic Valve Implantation (UK TAVI) trial at the virtual conference of the ACC's Annual Scientific Session Together with World Congress of Cardiology (ACC.20/WCC).
The trial showed that patients with severe aortic stenosis who underwent transcatheter aortic valve replacement (TAVR) did not have a higher rate of death at 1 year compared with those who underwent surgical valve replacement.
The ACC press release noted that previous clinical trials have found TAVR to be noninferior or superior to open surgery for various patient groups, but most trials have been limited to medical centers that perform a high volume of procedures or focus on the use of specific types of replacement valves.
The new trial involved a broad group of patients who were treated at every medical center that performs TAVR across the United Kingdom. The study was funded by the United Kingdom's National Institute for Health Research Health Technology Assessment Program.
Dr. Toff commented in the ACC announcement, “The importance of this trial is that it confirms the effectiveness of the TAVR strategy in a real-world setting. It wasn’t only conducted at the best centers, and it wasn’t limited to a particular valve under ideal conditions. This was TAVR as it is in the real world compared with surgery as it is in the real world.”
The ACC reported that the trial enrolled 913 patients referred for treatment of severe aortic stenosis at 34 sites in the United Kingdom from 2014 to 2018. Patients were randomly assigned 1:1 to receive TAVR and open surgery. Enrollment was limited to participants aged ≥ 70 years (with additional risk factors) or aged ≥ 80 years (with or without additional risk factors).
Overall, participants were at intermediate to low risk from surgery, with a median Society of Thoracic Surgeons risk score of 2.6%. However, the investigators did not specify a particular risk score cut-off for enrollment. This allowed the trial to evolve along with changes in guidelines and practice regarding TAVR over the course of the study and to reflect physicians’ nuanced, real-world approach to considering risk in decision-making rather than taking a formulaic approach, noted Dr. Toff in the ACC announcement.
At 1 year, the investigators found for TAVR versus open surgery patients:
- Lower death rate of 4.6% versus 6.6%, meeting the trial’s prespecified threshold for noninferiority of TAVR
- Similar rates of death from cardiovascular disease, stroke, and a composite of those two outcomes
- Significantly higher rate of vascular complications, 4.8% versus 1.3%
- Pacemaker implanted, 12.2% versus 6.6%
In addition, patients who underwent TAVR had a higher rate of aortic regurgitation at 1 year, a finding that might, in some cases, adversely affect long-term outcomes:
- Mild aortic regurgitation, 38.3% versus 11.7%
- Moderate aortic regurgitation, 2.3% versus 0.6%
However, patients undergoing TAVR had a significantly lower rate of major bleeding complications (6.3% vs 17.1%). Additionally, TAVR was associated with a shorter hospital stay and fewer days in intensive care.
At 6 weeks, TAVR patients showed better functional capacity and quality of life measures. But at 1 year, functional capacity and quality of life were similar between the two groups.
Dr. Toff advised that the results reflect a relatively short follow-up period, and that longer-term outcomes could reveal important differences. The UK-TAVI investigators plan to continue to track outcomes for a minimum of 5 years.
In the ACC announcement, Dr. Toff concluded, “I think it’s important that we take a measured approach and individualize the decision-making for these patients, factoring in the patient’s preference and attitude to risk. The results from our trial and others are encouraging, but patients need to be fully informed and know that the long-term durability of the TAVR valves and the long-term implications of the increased risk of aortic regurgitation are still uncertain.”