Transcatheter Tricuspid Valve Intervention Bests Meds for TR in Early Results

October 10, 2019

SAN FRANCISCO — The tricuspid valve has emerged as the setting for one of the next big chapters in transcatheter heart valve intervention, now that the aortic and mitral valve plotlines are so well developed.

In an international registry study, high-surgical-risk patients with symptomatic tricuspid regurgitation (TR) lived longer and were hospitalized less for heart failure (HF) if they underwent transcatheter treatment, compared with solely medical therapy.

Procedural success was key to the better outcomes of transcatheter tricuspid valve intervention (TTVI) in the case–control study with propensity matching. Such success was defined as survival with technically successful implantation and a significant reduction in TR.

Outcomes for those with unsuccessful procedures were about the same as for those managed with meds only.

The 1-year risk for death or HF hospitalization fell 40% (P = .003) and for mortality alone by 44% (P = .001) for the patients who underwent TTVI, achieved with the MitraClip (Abbott Vascular) in 85% of cases. The benefit was more pronounced when propensity matching was supplemented with further adjustment, including for atrial fibrillation (AF) and HF symptom status.

Maurizio Taramasso

On the basis of these findings, TTVI can be recommended for symptomatic patients with TR, "but it should be performed in selected patients and at high-volume centers" by dedicated interventional teams with a lot of TTVI experience, Maurizio Taramasso, MD, PhD, told | Medscape Cardiology.

Surgery for TR carries a high mortality risk, up to 15%, in part because the valve dysfunction tends to be very advanced by the time of referral to a surgeon, observed Taramasso, from University Hospital of Zurich.

But TTVI "is pretty safe, the rate of complications is really low. I'm not saying we should treat all patients, but we should be more prone to offer this kind of therapy even at a bit earlier stage." he said.

Taramasso presented the analysis here at Transcatheter Cardiovascular Therapeutics 2019 and is lead author on its same-day publication in the Journal of the American College of Cardiology.

Much progressive TR is thought to be secondary to mitral valve dysfunction, and "surgeons have a really low threshold for repairing the tricuspid valve at the time of mitral valve repair," observed Robert Bonow, MD, Northwestern University, Chicago.

But their threshold for isolated tricuspid valve surgery in such patients with advanced-stage TR is much higher, agreed Bonow, not connected with the current analysis.

"The surgeons lament that these patients are coming in too late," he said. "So the idea is to get this before the horse is out of the barn, at a lower stage." And that's where the field is heading, "to identify these patients early to treat them before they get this sick."

Correction of TR by transcatheter techniques could extend the treatment to more patients. But the current study has big limitations, Bonow said. "I don't want to minimize the importance of the observations, but it's not a perfect study. At least they're showing you can improve TR, and when you do that kind of comparison, the outcomes are not bad. But the outcomes are still not great; it's just that they're better than medical therapy."

There is also a big potential for unknown confounders. "The lack of a contemporaneous control does weaken the analysis," Bonow said.

The study was based on patients in Europe and North America in the Transcatheter Tricuspid Valve Therapies (TriValve) registry who underwent TTVI over a recent 2-year period. They received the MitraClip, but also FORMA, Cardioband, Trialign, PASCAL (all Edwards Lifesciences), TriCinch (4TECH), and NaviGate (NaviGate Cardiac Structures) devices.

Matched pairs were created from 268 TriValve patients and an equal number of patients from two large retrospective registries of patients in Europe and North America with at least moderate TR managed with medical therapy only. Matching was based on age, Euroscore II scores, and systolic pulmonary artery (PA) pressure.

Despite the matching, patients in the TTVI cohort from the matched pairs were more often men; had significantly more chronic AF, implanted devices with a lead positioned across the tricuspid valve, right ventricular dysfunction, and higher PA pressure; and had more advanced heart failure.

Mortality at 1 year was 22.6% for TTVI patients and 36.2% for medically managed patients (P = .0009) over a mean of 11 months. The HF rehospitalization rates were 26% and 47% (P < .0001), respectively.

One or both of those end points occurred in 32% and 49% of patients, respectively (= .0003), for a primary composite end point hazard ratio (HR) of 0.60 (95% CI, 0.46 - 0.79; = .003).

Because the matched pairs weren't always well matched for other potential confounders, Taramasso said, the analysis was adjusted further for sex, NYHA functional class, right ventricular function, AF, mitral regurgitation, and use of an implantable pacemaker or defibrillator.

In that analysis, the primary end point HR was 0.35 (95% CI, 0.23 - 0.54; P < .0001), and HR for any-cause death was 0.38 (95% CI, 0.23 - 0.63; = .002).

That the TTVI half of the matched patient pairs were sicker than those medically managed may improve the study's strength, Ajay M. Kirtane, MD, Columbia University and New York-Presbyterian Hospital/Columbia University, New York City, said at a media briefing on the analysis.

Selection bias can be common in an observational study, he said; there can be questions about why a particular management strategy was chosen for individual patients, especially if the strategy under scrutiny involves an established device.

"With a mature technology, you worry sometimes with these comparisons that if you show a benefit of the technology, if might just be that the patients who weren't treated were sicker," Kirtane said. But the reverse was true here, so the findings are "more reassuring than otherwise."

The better outcomes in the sicker intervention group "is even further argument" in favor of TTVI over medical management in such patients, Taramasso agreed when speaking with | Medscape Cardiology.

"Of course" there was some unavoidable selection bias, he said. But the different outcomes "all go in the same direction," and not only for symptomatic patients.

Taramasso discloses consulting for Abbott Vascular, Boston Scientific, 4TECH, and CoreMedic; and receiving speaker honoraria from Edwards Lifesciences. Bonow has previously disclosed no relevant financial relationships. Kirtane discloses receiving institutional funding from Medtronic, Boston Scientific Corporation, Abbott Vascular, Abiomed, CSI, CathWorks, Siemens, Philips, and ReCor Medical. 

J Am Coll Cardiol. Published online September 27, 2019. Abstract

Transcatheter Cardiovascular Therapeutics (TCT) 2019: Late Breaking Science 2. Presented September 27, 2019.

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