Current State of Percutaneous Valve Therapies for Use in Congestive HF Explored

During a didactic symposium on Monday, experts discussed the current state and use of transcatheter aortic valve replacement (TAVR), percutaneous mitral valve replacement and percutaneous tricuspid valve annuloplasty to treat patients with congestive HF, a particularly difficult population to address when considering use of transcatheter valve procedures. 

TAVR

Based on registry studies, it is estimated that about one-third of patients undergoing TAVR and surgical AVR have a left ventricular ejection fraction (LVEF) below 30%, suggesting that HF is relatively common in patients undergoing these procedures, according to Jeroen J. Bax, MD, of Leiden University Medical Center, Leiden, the Netherlands. However, in many cases, the severity of aortic stenosis (AS) is unclear, as is the benefit of TAVR in this population, he said.

With regard to diagnosis, patients with low-flow, low-gradient AS who receive dobutamine can then be assessed based on change to aortic valve area and mean gradient. If the valve area remains low and the mean gradient rises, true severe AS is likely present, Bax said.

As for the effects of TAVR, several studies have shown mortality reduction and improvement in LVEF following the procedure in patients with low-flow, low-gradient AS. Risk stratification is important, however; patients with contractile reserve may be better candidates for TAVR, Bax said.

Mitral valve therapies

John D. Carroll, MD, of the University of Colorado, Denver, Colo., addressed the question of whether percutaneous mitral valve replacement or annuloplasty are reasonable therapies for congestive HF patients with severe mitral regurgitation (MR). He noted that it is common to see patients with hemodynamically severe mitral valve disease who are not candidates for surgery.

“For those who are not candidates for surgery, there is clearly a need,” Carroll said. “We need more transcatheter options and more clinical studies” that look into specific subpopulations.

Available data indicate that the patient population in question tends to be elderly and frail, with advanced HF and a substantial comorbidity burden. One report from the Society of Thoracic Surgeons/American College of Cardiology TVT Registry showed that the median age of patients undergoing transcatheter mitral valve repair was 83 years, with 83.9% of patients in NYHA class III or IV. Many patients (62.6%) also had atrial fibrillation.

Given the high risk of the population, the specifics of the technologies used matter greatly, according to Carroll. Most transcatheter mitral valve replacements require transapical access, and “alternative access carries with it higher risks,” he said.

Carroll pointed to a lack of prospective randomized data on transcatheter mitral annular approaches in this population. The trials that have taken place, such as TITAN I and II and AMADEUS, were nonrandomized and included small patient numbers.

He concluded that mitral valve replacement or annuloplasty are likely reasonable treatments for congestive HF patients with severe MR. “But there are still more unknowns than knowns about these therapies,” Carroll added.

The target population will initially be those with prohibitive surgical risk, as first-generation technologies will be challenging to use and burdensome on patients, he said.

Triscupid valve annuloplasty

Tricuspid regurgitation is severely undertreated in the United States, according to Adam Groothuis, PhD, of Mitralign Inc. Of the estimated 1.6 million patients with tricuspid regurgitation, just 5,500 annual surgeries are performed. Available research has indicated that tricuspid regurgitation is common in HF patients in particular. Further, the condition may have a substantial impact on survival.

At present, several dedicated tricuspid technologies have been developed, including the TriCinch System (4Tech Cardio) for annular lateral annuloplasty; a Mitralign device for posterior annuloplasty; and the Forma Repair System (Edwards Lifesciences), which features a space-filling balloon attached to the right ventricular apex. Data on these devices are limited at this point, Groothuis said. Still, he said the early results are “promising,” with acute safety and efficacy shown in small numbers of patients. “That’s as good as we can do at this point,” he said.

Disclosures:

• Bax reports receiving departmental research grants from Biotronik, Boston Scientific Corporation, Edwards Lifesciences and Medtronic. 
• Carroll reports receiving consultant/honoraria fees from Tendyne Holdings. 
• Groothuis is a full-time employee of Mitralign Inc.