Win for MitraClip as Bridge to Transplant

MitraClip transcatheter mitral valve repair was safe as a bridge to heart transplant and even helped some patients become eligible for transplant, a pilot study showed.

In a largely European registry of 119 chronic advanced or end-stage heart failure patients with 3+ or 4+ mitral regurgitation (MR) who were potential candidates for heart transplantation and got the MitraClip as a bridge strategy:

  • 23.5% recovered sufficiently to go off the heart transplant list
  • 15.5% became eligible for transplant

Freedom from the primary composite endpoint of all-cause mortality, urgent heart transplant, or left ventricular assist device implantation occurred in 64%, Cosmo Godino, MD, of San Raffaele Hospital in Milan, Italy, reported at the virtual TCT Connect conference.

There were no deaths within 30 days of implantation and 86% procedural success.

The population studied may account for somewhere between 1% and 10% of the total heart failure population and are difficult to manage, with a 1-year mortality risk of 15% on the transplant wait list in Europe, Godino noted.

The study used retrospective clinical records from 119 patients from 17 centers in Europe and Canada:

  • 31 were on the transplant list with low likelihood of receiving a donor organ soon due to factors like blood type or body weight
  • 54 were awaiting a clinical decision on transplant, dubbed bridge-to-decision
  • 34 were not yet listed for transplant due to potentially reversible contraindications, such as severe pulmonary hypertension or elevated pulmonary-vascular resistance, and got the device as a bridge to candidacy

David J. Cohen, MD, of Kansas City, Missouri, noted that the findings did match up with his group’s COAPT trial in that MitraClip was associated with half as many patients going to transplant or left ventricular assist device (LVAD) in that trial.

“Since COAPT came out, we’ve been getting a lot more consults from the transplant service for patients just like this as a bridge to get them safer, keep them out of the hospital, keep them off of inotropes until they’re ready for a destination,” noted Chad Rammohan, MD, of El Camino Hospital in Mountain View, California.

“What’s interesting is that these patients would probably fit into the MITRA-FR data by the size of their LVs [left ventricles], which is interesting because that trial was negative,” he said as part of a discussion panel at a TCT press briefing.

Indeed, about 80% of the population wouldn’t have fit into the COAPT trial criteria, and some were even beyond the MITRA FR criteria, Godino noted. LV end diastolic volume index averaged 122.5 mL/m2.

“So it’s strange that we found some positive results,” he said. The explanation may be the young age of patients, averaging 58 — 20 years younger than that in the MITRA-FR trial, he noted.

“There’s a lot we don’t understand about which LVs are going to benefit — the LV mechanics — and there’s a lot of variability,” agreed panelist Susheel Kodali, MD, of NewYork-Presbyterian/Columbia University Medical Center in New York City. “This is a very sick population, and the procedure was safe. Outside of cost, you didn’t lose a lot. … That’s key for me.”

Saibal Kar, MD, of Los Robles Regional Medical Center in Thousand Oaks and Bakersfield Heart Hospital, both in California, agreed on that bottom-line message. “If I tell a patient who’s almost going to transplant or cannot get a transplant, a young patient … it’s extremely safe but there’s probably a 15% chance you won’t need a transplant, they will say do it! So for me it’s a no brainer. The indication of MitraClip is a femoral vein and a mitral valve.”

COAPT trialist Gregg Stone, MD, of Icahn School of Medicine at Mount Sinai in New York City, commented at the session that the trial included many patients that would have fallen into Godino’s bridge to candidacy category and probably some of the bridge to decision group.

Michael Mack, MD, of Baylor Scott & White Health in Plano, Texas, was skeptical about pooling the three “very different” transplant candidate groups studied. “I’m not sure what patient I can discern from this would benefit from this.”

He pointed out that 6% of patients had urgent transplant and 18% got an LVAD, so “how can we know that this is safe and that we didn’t actually accelerate the need for a VAD or transplant with that?”

Godino acknowledged that the conclusions should be considered exploratory and hypothesis generating, with further study needed.

Kar presented at the same session that the third-generation MitraClip NTR and XTR systems, introduced in 2018, appeared to be doing better than prior generations of the device for approved indications.

In the 1,041-patient EXPAND real-world registry of patients in the U.S. and Europe, the 1-year external core lab-adjudicated mitral regurgitation severity was graded as 1+ or less in 89.2% of patients and only trace regurgitation in 18.9%.

For primary mitral valve disease, regurgitation was no more than mild for 84.5%; in the secondary mitral valve disease setting, it was 93%.

“If you compare this dataset to REALISM or the EVEREST trial, you can see that there’s a significant improvement of MR reduction compared with these previous studies,” Kar said. The data was quite similar to COAPT, he noted.

Quality of life on the Kansas City Cardiomyopathy Questionnaire improved significantly from baseline to 1 year, with a 21.6 point increase on the scale where 10 points is considered clinically meaningful. Annualized heart failure hospitalization risk was a relative 63% lower at 1 year after getting the clip compared with the year prior (P<0.001).

Mack cautioned about survivorship and acquisition bias, with 1-year echo follow-up in only about 55% of patients.

Disclosures

Godino disclosed no relevant relationships with industry.

EXPAND is funded by Abbott.

Kar disclosed relationships with Abbott, Boston Scientific, Edwards Lifesciences, W.L. Gore, and Medtronic.

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