MitraClip Issues, Outcomes Come to Fore in US Registry Experience

  Patrice Wendling

March 23, 2017

WASHINGTON, DC — Registry data suggest 1-year clinical outcomes in the US with the MitraClip (Abbott Vascular) transcatheter mitral-valve (MV) system mirror those achieved in clinical trials[1].

There is a subset of these high-risk patients, however, "who have a persistent risk of mortality as well as heart-failure hospitalization at 1 year," although "certain clinical factors and also the degree of mitral regurgitation [MR] reduction can help predict the risk of these long-term adverse outcomes," Dr Paul Sorajja said during his presentation at the American College of Cardiology (ACC) 2017 Scientific Sessions .

The MitraClip system was approved in October 2013 in the US, with currently more than 250 active centers. Last year, the company took voluntary action to reinforce proper procedures used to operate and deploy the device after reports surfaced of improper use requiring surgical intervention.

Dr Paul Sorajja

For the study, Sorajja and his colleagues identified 2952 patients (median age 82 years; 55.8% male) from the Society of Thoracic Surgeons/ACC Transcatheter Valve Therapy (TVT) registry who had their procedures through September 2015 and linked Centers for Medicare & Medicaid Services (CMS) claims data available for clinical outcomes for 1867 (63%) patients.

Most patients (93%) had grade 3 or 4 mitral regurgitation (MR), 85.9% had degenerative MR only, and 8.6% had functional MR only. Functional MR is not an approved indication in the US, although it is the most common way the MitraClip is being used in Europe in almost two-thirds of patients.

Acute procedural success, defined as postprocedural MR grade <2 without surgery or death, was 92.8%. In-hospital mortality was 2.7%.

The cumulative incidence of death at 1 year was significantly higher for patients with functional vs degenerative MR (31.2% vs 24.7%; P =0.028) and for those with severe tricuspid regurgitation vs lesser-degree tricuspid regurgitation (38.5% vs 23.5% moderate and 23.4% mild/none; P<0.0001).

Higher-grade postprocedural MR was also a powerful link to mortality, with the incidence of death reaching 48.9% for residual grades 3/4 MR vs 29.2% for grade 2 MR and 21.7% for grades 1/0 MR (P<0.0001). The same findings were also present for heart-failure hospitalization, Sorajja said.

During the discussion of the data, session cochair Dr Gregg W Stone (Columbia University Medical Center, NY) remarked that the tricuspid-regurgitation finding was particularly striking and asked what the implications are for the MitraClip procedure in MR patients with severe tricuspid regurgitation.

Sorajja responded, "It's interesting because the number of tricuspid-regurgitation patients was 16%. It was very high, and in our practice when we're looking at MitraClip patients, if there is severe tricuspid regurgitation, our surgeons, rightly so, will say, 'I don't think you're going to help these patients.' "

He added, "Generally we tend to look at volume status, how compensated they are, and whether they truly are suffering from right heart failure related to the tricuspid regurgitation, but I think it's an important lesion, and what the data show is that untreated morbidities really add to patient prognosis."

Panelist Dr Francesco Maisano (Zurich University Hospital, Switzerland), who Stone described as leading the charge for tricuspid MitraClip repair, said, "In Europe, we have an open mind to treat the tricuspids; however, we don't know whether tricuspid insufficiency is just a marker of more advanced disease or if treating tricuspid regurgitation is changing prognosis. This is still a challenging question."

He continued, "On the other hand, technically it is feasible; we can reduce tricuspid regurgitation by planting clips and it will become more and more a standard practice in our institutions."

Asked how he manages patients with MR plus tricuspid regurgitation, Stone told heartwire from Medscape, "The patients with degenerative MR are referred to us when they have really no alternatives and are highly symptomatic with severe MR, and in that case the MitraClip in our hands has been very low risk; so we would usually offer that therapy to them regardless of the tricuspid regurgitation and we'll let them know certainly that that is a negative prognostic factor.

"We don't know if they're going to be helped as much, but we are trying to get these patients symptomatic improvement more than a reduction in mortality."

In multivariate models, presence of severe tricuspid regurgitation was a significant predictor of 1-year mortality along with increasing age (per 5 years), use of dialysis, moderate or severe lung disease, lower ejection fraction, and presence of residual MR.

Panelist Dr Megan Coylewright (Dartmouth-Hitchcock Medical Center, Lebanon, NH) told heartwire , "Overall, the data are very helpful because we need long-term data, and although it's only a year, it really helps us guide patients in terms of expectations."

Coylewright continued, "The data are also really important because they have the potential to influence us as operators and thinking about the importance of really bringing mitral regurgitation down to 1-plus, because we saw in the analysis that that really leads to better outcomes. It's complex; the people who can get that result often have other anatomical features that allow you to do that, but at the same time it is striking compared with prior data that 2-plus may not be enough."

Sorajja said the study's 1-year mortality and HF hospitalization rates were comparable with those in clinical trials, despite TVT registry patients being generally older and having a higher prevalence of degenerative mitral regurgitation.

Comparative Studies

Study Age (y) DMR (%) Acute success (%) 1-y mortality 1-y HF hospitalization
STS/ACC TVT 82 85.9 92.8 25.9 20.2
SENTINEL 74 28 95.4 15.3 22.8
ACCESS-EU 74 20.6 91.7 19.2 19.8
EVEREST II HRS 76 29.9 86.0 22.8 NA
EVEREST PR 82 100 95.3 23.6 18.0

To heartwire , panelist Dr Howard Herrmann (University of Pennsylvania, Philadelphia) said, "I was impressed that the safety of the procedure and the long-term outcomes reproduced to a great extent what we saw in high-risk trials of MitraClip and suggest we can generalize this therapy to a lot of operators at a lot of sites. That's the good news.

"The bad news is these are very sick patients and despite successful clips in some and unsuccessful clips in others, these patients have a very high subsequent mortality."

The study was supported by a grant from Abbott Vascular, with support from the ACCF National Cardiovascular Data Registry and the Society of Thoracic Surgeons National Database. Sorajja reported consultant fees/honoraria from Medtronic, Lake Regional Medical, and Abbott Vascular and serving on speaker's bureaus for Boston Scientific and Abbott Vascular. Stone reported consultant fees/honoraria from Ablative Solutions, BackBeat Medical, Coherex, Guided Delivery Systems, Medical Development Technologies, Miracor, Neovasc, Reva, TherOx, Vascular Dynamics, and V-Wave; and ownership interest/partnership/principal status in Aria, Biostar family funds, Cagent, Caliber, Medfocus family funds, Micardia, Qool Therapeutics, and Vascular Nonotransfer Technologies. Maisano reported consultant fees/honoraria from Abbott Laboratories, Abbott Vascular, Medtronic, St Jude Medical, and Valtech Cardio; other relationships with 4Tech Cardio and Edwards Lifesciences; ownership interest/partnership/principal status with 4Tech Cardio, Affix, and Transseptal Solutions; and research grants from Abbott Laboratories and Abbott Vascular. Coylewright reported consultant fees/honoraria from Boston Scientific. Herrmann reported consultant fees/honoraria from Edwards Lifesciences, Leerink Swan, and Wells Fargo; other relationships with the Massachusetts Medical Society; ownership interest/partnership/principal status with Micro-Interventional Devices; and research grants from Abbott Vascular, Boston Scientific, Edwards Lifesciences, Medtronic, MitraSpan, and St Jude Medical.

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