VARC-3 TAVR Technical Failure Definition 'Highly Clinically Relevant'

A new study offers early validation of the recently released Valve Academic Research Consortium 3 (VARC-3) definition of technical success after transcatheter aortic valve replacement (TAVR), and highlights its role in patient prognosis.

Results show that one in 10 patients (11.6%) undergoing TAVR with contemporary devices and techniques experiences technical failure, according to VARC-3.

At 30 days, patients with technical failure had significantly higher rates of the composite of cardiovascular (CV) death or stroke (11.5% vs 3.5%), CV death (6.0% vs 1.0%), and stroke (7.2% vs 2.9%), compared with those with technical success.

Technical failure after TAVR was also independently associated with a twofold higher risk for CV death or stroke at 1 year (20.0% vs 10.3%; hazard ratio [HR], 2.01; 95% CI, 1.37 - 2.95).

Other independent predictors were history of peripheral artery disease (HR, 1.97), New York Heart Association III or IV disease (HR, 1.86), baseline moderate or greater mitral regurgitation (HR, 1.48), atrial fibrillation (HR, 1.40), and Society of Thoracic Surgeons predicted mortality risk (HR, 1.04).

"We were expecting that we were getting better over time with device iterations, with more experience, so we weren't surprised by the result. But I think what is somewhat surprising is how much of an impact it has on the outcome," senior study author Thomas Pilgrim, MD, Inselspital, University of Bern, Switzerland, told theheart.org | Medscape Cardiology.

The VARC-3 document, introduced last year to some controversy, features a heavier focus on patient outcomes, as well as composite safety and efficacy endpoints. The definition of technical success after TAVR includes:

• freedom from death

• successful access, delivery of the device, and retrieval of the delivery system

• correct positioning of a prosthetic heart valve into the proper anatomical location

• freedom from surgery or intervention related to the device or to an access-related or cardiac structural complication.

The composite endpoint is meant to replace the VARC-2 definition of "device success," which also included freedom from death and correct valve positioning but required echocardiographic evaluation. With VARC-3, there is an "immediate measure" of success without having to wait for echocardiography, observed Pilgrim.

As reported in the Journal of the American College of Cardiology Cardiovascular Interventions, TAVR was a technical success in 1435 of 1624 (88.4%) patients. Technical failure occurred in 189 patients related to either vascular complications (8.6%) or procedural death or cardiac complications (3.0%).

The VARC-2 endpoint of device success was observed in 66.1% of patients. The high rate of device failure was largely attributed to a 28% incidence of prosthesis–patient mismatch.

"If you use the VARC-2 device success [definition], you include this patient–prosthesis mismatch, the [valve] gradients, regurgitation, and, then, device success is always lower," Pilgrim said.

Asked whether the VARC-3 definition may be missing case failures, he replied: "At this stage, we don't know how important these echocardiographic parameters are for hard clinical endpoints. Maybe the VARC-2 endpoint was too sensitive or the VARC-3 endpoint is not sensitive enough. This is something we just don't know at this stage."

Marco Barbanti, MD, an interventional cardiologist at Rodolico Polyclinic University Hospital-San Marco, Catania, Italy, and author of an accompanying editorial, said VARC-3 represents a more accurate indicator of immediate success of the procedure.

"It's a more pertinent definition according to what really has an impact on prognosis and, according to the results of this paper, actually, the calibration of this new definition is quite good," Barbanti said in an interview.

Patients with VARC-3 technical failure were older, had a higher body mass index, and had more advanced heart failure symptoms than those with technical success. There were no significant differences between the two groups in echocardiographic or CT data, anesthetic strategy, valve type or size, and use of pre- or post-dilation.

All patients underwent TAVR with current balloon-expandable (Sapien 3/Sapien Ultra, Edwards Lifesciences) or self-expanding (Evolut R/PRO [Medtronic], Portico [Abbott], Symetis ACURATE/ACURATE neo [Boston Scientific]) devices between March 2012 and December 2019. A transfemoral approach was used in 92.5% of patients.

In a landmark analysis with the landmark set at 30 days, the effect of technical failure on adverse outcome was limited to the first 30 days (composite endpoint 0 - 30 days: HR, 3.42; P < .001; 30 - 360 days: HR, 1.36; P = .266; P for interaction = .002).

At 1 year, the composite of CV death and stroke endpoint occurred in 24.1% of patients with cardiac technical failure, in 18.8% of patients with vascular technical failure, and in 10.3% of patients with technical success.

In multivariate analyses, cardiac and vascular technical failures were independently associated with a 2.6-fold and 1.9-fold increased risk, respectively, for the composite of cardiovascular death and stroke at 1 year.

Female sex, larger device landing zone calcium volume, and earlier procedures (March 2012 to July 2016) were associated with a higher risk for cardiac technical failure, whereas, consistent with previous studies, higher body mass index and use of the Prostar/Manta vs the ProGlide closure device predicted vascular technical failure.

The findings "underscore that technical success is highly clinically relevant and may serve as one of the pivotal endpoints to evaluate the improvement of TAVR or for head-to-head comparisons of new devices in future clinical trials," the authors conclude.

The findings reflect the experience of a single high-volume center with highly experienced operators in the prospective BERN TAVR registry, however, and may not be generalizable to other heart centers, they note. Although the registry has standardized follow-up, independent analysis of echocardiographic and CT, and independent event adjudication, vascular anatomy was not systematically assessed and the potential exists for confounding from unmeasured variables.

Pilgrim reports research grants to the institution from Edwards Lifesciences, Boston Scientific and Biotronik, personal fees from Biotronik and Boston Scientific, and other from HighLife SAS. Coauthor disclosures are listed in the original paper. Barbanti is a consultant for Edwards Lifesciences and Boston Scientific.

J Am Coll Cardiol Intv. Published online January 26, 2022. Abstract, Editorial

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