SNOWMASS, COLO. – Achieving optimal surgical-like results via transcatheter repair of primary mitral regurgitation using the MitraClip in prohibitively high-surgical-risk patients becomes much more likely by taking into account key predictive anatomic and procedural features as well as the major comorbidities influencing outcome, Paul Sorajja, MD, said at the Annual Cardiovascular Conference at Snowmass sponsored by the American College of Cardiology.
. Dr. Sorajja was first author of a study of 1-year outcomes in 2,952 patients with MR in the Society of Thoracic Surgery/American College of Cardiology Transcatheter Valve Therapy Registry (STS/ACC TVT) who were commercially treated with the MitraClip, at present the only transcatheter device approved for this indication. Sixty-two percent had a surgical-like result, and their 1-year mortality rate of 21.7% was significantly lower than the 29.2% rate for patients with residual grade 2 MR and the 48.9% mortality in patients left with grade 3 or 4 MR.
It’s noteworthy that even though the acute procedural success rate – defined as residual grade 2 or less MR – was impressively high at 91.8% in this group of nearly 3,000 patients, roughly one in five in the overall series was rehospitalized for heart failure within 1 year, and one in four was dead. So there remains considerable room for improvement in long-term outcomes of transcatheter repair of MR, said Dr. Sorajja, director of the Center of Valve and Structural Heart Disease at the Minneapolis Heart Institute.
Anatomic predictors of good short-term outcome
“There are specific anatomic criteria, but an easier way to think about whether your patient could get an optimal result is to remember the physical limits of this therapy. What I teach is 1-2-5-50: the MitraClip device is about 1 cm tall, about 2 cm wide, and you need about 5 mm of leaflet inside the clip to create coaptation for MR reduction. And if you do that, you will reduce the mitral valve area by about 50%, so you have to be very careful in patients with small valve areas because you can worsen mitral stenosis,” the cardiologist explained.
Only two transechocardiographic views are needed to know if a patient will have a good result with the MitraClip. A bicommissural view traversing the valve medial to lateral shows where the MR jet is; if it’s in the middle of the mitral valve, that’s favorable because it means the interventionalist has a lot of freedom to operate. Then, going orthogonal from the bicommissural view to get an anterior-posterior view allows the operator to get a good look at the valve leaflets and apply the 1-2-5 rule to determine if the leaflet approximation is favorable, he continued.
Some mitral valve anatomy variants make it challenging to get surgical-like results with a transcatheter repair. These include calcified leaflets, large gaps between leaflets, Barlow’s valves, and small leaflets. Be aware of key success-limiting comorbidities.
In the STS/ACC TVT registry study, severe tricuspid regurgitation, present in 10% of patients preprocedurally, virtually doubled the adjusted risk of 1-year mortality in multivariate analyses.
“Tricuspid regurgitation is one of the most common concomitant lesions. And the presence of tricuspid regurgitation is ominous,” Dr. Sorajja said. “Treatment of concomitant lesions such as this is going to be necessary for us to get a truly surgical-like result in outcomes.”
Toward this end, he put in a plug to consider referring patients with severe tricuspid regurgitation for enrollment in the TRILUMINATE II trial, the pivotal U.S. trial for the investigational Tri-Clip device for transcatheter tricuspid valve repair, for which he is coprincipal investigator. The trial, pitting the Tri-Clip against medical therapy, is due to start in the spring of 2019.
In multivariate analyses of the MitraClip registry study, other predictors of the combined endpoint of death and rehospitalization for heart failure at 1 year, in addition to severe tricuspid regurgitation, included dialysis, with an adjusted 2.09-fold increased risk; moderate or severe lung disease, with a 1.28-fold risk; postprocedural residual MR; diminished left ventricular ejection fraction; and advanced age (J Am Coll Cardiol. 2017 Nov 7;70:2315-27).