Valve Deterioration and Durability Definitions Now Standardized in New Guide

LONDON, England—Concerns over the incidence and timing of bioprosthetic valve dysfunction and failure—and the different ways these have historically been defined—have prompted the creation of a new consensus statement. Davide Capodanno, MD, PhD (University of Catania, Italy), presented the “standardized definitions of structural deterioration and valve failure” here at PCR London Valves 2017. The document was published this month in the European Journal of Cardiothoracic Surgery.

“After the first reports of long-term valve failure, which were inconsistently reported and raised a lot of issues in terms of methodology, we felt it was important to bring some standardization to the field, especially in preparation for the studies of long-term durability and outcomes and particularly comparing TAVI and surgery,” Capodanno told TCTMD. “The surgeons have guidelines for the reporting of long-term durability, which are good, but it was important to align those with the TAVI field.”

As previously reported by TCTMD, the debate over valve deterioration and durability has occurred on the background of studies hinting that TAVR valves may not be as durable as their surgical counterparts. Critics of those studies, however, have pointed out that deterioration of surgical valves—and even leaflet mobility and thrombosis—has not been as rigorously tracked as that of transcatheter devices, the idea being: the more you look, the more you find. On the other hand, looking for clinically relevant valve dysfunction earlier in the disease process may lead to treatments that could prevent more serious structural problems, Capodanno explained.

Another key piece of the puzzle has been how to differentiate between bioprosthetic valve dysfunction and outright failure. In the past, surgical series have typically defined failure as the need for reintervention. In recent years, surgeons have increasingly used echocardiography to explore valve durability, but echocardiographic definitions have been variable and inconsistently applied, Capodanno said.

“We thought it was important to bring to the table both surgeons and interventionalists in order to find common ground for this endpoint reporting, and I think we did a nice job with a lot of harmony and collaboration,” Capodanno said. “The most important thing is that we wanted something that was clinically impactful. We didn’t want to put things in the document that you just see, but that have no impact on the patient’s quality of life.”

Durability Definitions

As the document sets out, bioprosthetic valve dysfunction encompasses not only structural valve deterioration (SVD; defined by intrinsic permanent changes such as calcification, leaflet fibrosis, tears, or flail) but also nonstructural valve deterioration (regurgitation, prosthesis malposition, patient-prosthesis mismatch, late embolization, etc), thrombosis, and endocarditis. These last two, noted Capodanno, are to some extent reversible but if not identified and treated, they can lead to permanent SVD.

A new addition is the patient-oriented clinical endpoint bioprosthetic valve failure (BVF), which, as noted in the document, "aims to capture the clinically relevant manifestations and consequences of SVD or other forms of bioprosthetic valve dysfunction."

Understanding how to find, quantify, and track different forms of dysfunction is therefore important not only for patients who have already undergone surgical and transcatheter procedures but also crucial for new and ongoing studies. Indeed, the current definitions were finalized prior to the initiation of a European registry intended to improve the characterization of SVD and BVF, in line with ongoing efforts by the Valve Academic Research Consortium 3.

The new document proposes, among other things, that:

• Clear distinction must be made between SVD as the principal etiology and BVF as the clinical correlate.
• SVD causes irreversible dysfunction, whereas other causes of bioprosthetic valve dysfunction may be reversible if identified in a timely manner. Both endocarditis and thrombosis may cause permanent BVF.
• Some SVD may be the result of technical issues/faulty implantation, but when resulting from nonstructural valve dysfunction still qualifies as BVF.
• Echocardiography is the principle imaging modality for detecting SVD and most accessible for detecting serial changes. Recommended timing of echocardiography is before discharge or within 30 days of both SAVR or TAVR, and annually thereafter.

Clear and Simple

Commenting on the document for TCTMD, Ori Ben-Yehuda, MD (Cardiovascular Research Foundation, New York, NY), called the definitions “very clear and simple,” saying that they are in line with what many cardiologists are already doing as part of routine clinical care. “Seeing what happens to the valve makes sense for a variety of reasons, and we’re not only looking at the valve,” he noted. “These patients often also have heart failure or coronary disease, or a previous MI, so following their echocardiograms on a serial basis makes sense for these patients anyway.”

For those reasons, Ben-Yehuda said he was particularly pleased to see the emphasis on the need for a baseline echocardiogram postprocedure, pointing out its implications for insurance and reimbursement. “This is a very common sense document, and it’s nice to see it in a simple guideline because this allows standardization and allows for a reason for reimbursement, which is often an impediment to good patient care,” he said.

Ben-Yehuda’s only quibbles with the document were the lack of “transatlantic collaboration” within the expert panel and the lack of detailed guidance on the rationale for and timing of cardiac CT. “What do we do and how should we act,” he asked, “if we see not a functional but anatomic deterioration? A decrease in valve mobility suggesting early on that there may be an issue of leaflet thrombosis or see actual thrombosis?”

Asked about the lack of detailed guidance on CT imaging in the document, Capodanno noted that the paper provides an algorithm to help readers understand when multidetector CT may have a role and also points readers to other guidelines and papers that have covered CT imaging for leaflet mobility and thrombosis in greater depth.

Also commenting on the new definitions for TCTMD, Alexandra Lansky, MD (Yale School of Medicine, New Haven, CT), called them a "clear and needed framework on how to assess, define, and report valve dysfunction and failure."

Clear definitions will have multiple applications, Lansky explained in an email. "Given the early stage of TAVR development and its rapid expansion into lower-risk and likely younger patients, the task force recommendations will enable systematic benchmarking of valve dysfunction and failure rates."

This will be important not only for postmarket registries, but also "greatly needed to inform the dialogue with our patients," she predicted.

"Whether a practice of routine annual echocardiograms turns out to be a cost effective approach in clinical practice and will stand the test of time depends largely on actual rates of SVD and BVF and the extent to which annual echo surveillance can mitigate valve failure," Lansky concluded.   

Annual Echo for All?

In a discussion following Capodanno’s presentation, session co-moderator Martin Leon, MD (NewYork-Presbyterian/Columbia University Medical Center, NY), asked members of the panel whether they agreed with the recommendation for annual echocardiography and whether this was something that should be done only in the research setting or expanded to the clinical setting.

Jeffrey Popma, MD (Beth Israel Deaconess Medical Center Boston, MA), replied: “We do it for TAVR now as part of our clinical practice, but we have not done it for surgical valves. So I think the bar needs to be the same, whatever we decide.”

Cardiothoracic surgeon Gregory Fontana, MD (Lenox Hill Hospital, New York, NY), called annual echocardiography “a great idea.”

“I just don’t know what the economics of it are, but certainly I’ve always thought it was important and I’ve worked in practices where it’s been the guideline followed,” Fontana commented. “I do think we will see a lot more interventions if we see the valve deteriorating on echo, but I think in terms of planning ahead for the patient that it’s good to anticipate the timing. I believe it’s already practiced in a number of environments, but it’s not consistent.”

Leon noted that annual echocardiography performed in the PARTNER trial showed significant hemodynamic fluctuation, year to year, in individual patients. “So that needs to be looked at carefully, with a lot of perspective,” if it’s going to be applied to all patients, he advised. “It’s a fascinating issue, and I would like to see the same approach for both surgery and transcatheter valves—but that may be unrealistic.”