Post-repair MR may be worse than thought

Key clinical point: Residual mild mitral valve regurgitation (MR) after implantation of the MitraClip device (Abbott Vascular) was associated with worse survival, symptom relief, and risk of moderate or severe MR than residual trace MR after implantation.

Major finding: Patients with residual mild MR after MitraClip implantation had a 45% probability of recurrence of moderate or severe MR within 4 years, more than three times that of those who had residual trace MR.

Data source: Population of 223 consecutive patients with acute residual trace or mild MR after MitraClip implantation between 2008 and 2014 at a single institution.

Disclosures: Dr. Nicola Buzzatti and Dr. Paolo Denti disclosed receiving consultant fees from Abbott Vascular. Dr. Fabio Barili disclosed receiving consultant fees from St. Jude Medical. The other authors had no relationships to disclose.

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Challenging meaning of ‘success’ after MVR

In interpreting the findings of the Italian study and applying them in the clinic, one must consider the etiology of mitral valve regurgitation (MR) because that can determine the outcome of transcatheter mitral valve repair, Dr. Vincent Chan and Dr. Marc Ruel of the University of Ottawa Heart Institute said in their invited commentary (J Thorac Cardiovasc Surg 2016;151:97-8).

“In patients with coronary artery disease, it is well known that the presence of moderate chronic ischemic MR is associated with worse survival and more congestive heart failure compared to patients without MR,” Dr. Chan and Dr. Ruel said.

In a series his group studied, they noted that recurrent moderate MR was more common after MV repair than replacement; the survival rates between the two groups were similar (Ann Thorac Surg. 2011;92:1358-1365). That may be because late left ventricle (LV) function was similar between patients who had recurrent moderate MR and those that did not, but the Italian study did not clarify difference in late LV function between functional MR patients. “Perhaps differences in clinical outcome between patients with MR 2+ and MR ≤1+ relate to differences in ventricular function that portend mortality?” they asked.

They also called the researchers’ assertion that moderate MR impacts outcomes after repair “interesting.” They cited studies that linked effective worse outcomes to effective regurgitant orifice area (EROA) of 20-39 mm2, but that the complexity of echocardiographic measurement raises challenges in calculating EROA (Circulation. 2001;103:1759-64; N Engl J Med. 2005;352:875-83). “Also residual prolapse following MitraClip, as with any prolapse, may be brief and therefore instantaneous measures or regurgitation with pulse wave Doppler may be limited,” they said.

While percutaneous approaches to treat MR have “revolutionized” the care of these patients, the technology has its limitations, Dr. Chan and Dr. Ruel said. “Although many patients benefit from this therapy, the understanding of incomplete MR reduction with this technology continues to evolve.”

They had no disclosures.




In patients who undergo transcatheter mitral valve repair for mitral valve regurgitation (MR), residual mild (+2) regurgitation has been considered procedural success, but a team of Italian investigators has provided evidence that such a result may actually foretell far worse long-term outcomes than residual trace (≤1) MR.

The investigators from San Raffaele Scientific Institute in Milan reported their findings in the January issue of the Journal of Thoracic and Cardiovascular Surgery (J Thorac Cardiovasc Surg 2016;151:88-96). They compared follow-up outcomes of 223 consecutive patients with residual MR 2+ and MR ≤1 after implantation of the MitraClip system (Abbott Vascular). The procedures were performed between October 2008 and December 2014.

“In this study we found a clear unfavorable impact on follow-up outcomes of acute residual 2+ MR after MitraClip repair when compared to residual ≤1+ MR,” lead author Dr. Nicola Buzzatti and colleagues said.

The study cited a scarcity of data on the long-term impact of residual mild MR. “This topic is therefore particularly of interest, especially when assessing the convenience to expand transcatheter mitral repair procedures to intermediate or low-risk patients,” Dr. Buzzatti and coauthors said.

The study group all had moderate or greater (≥3+) MR when they underwent mitral valve repair (MVR). The post-MVR study cohort excluded patients who had residual MR of 3 or greater, which was considered a procedural failure. Four patients died within 30 days, each from a different cause: multi-organ failure, lung rupture, pneumonia with heart failure, and sudden death. The overall 30-day death rate was 1.8%.

Among the remainder of patients, the average follow-up was 20.5 months, with some follow-up extending to 75 months. The overall survival was 74.4% at 24 months and 63% at 48 months.

The study calculated the cumulative incidence function, or the probability of failure, of cardiac death in patients with residual MR ≤1 at 7.1% at 24 months and 10.9% at 48 months, compared with 26.9% at 24 months and 35.3% at 48 months in those with MR 2+. The probability of failure of recurrence of moderate or severe MR with residual MR ≤1 was 5.6% at 24 months and 13.3% at 48 months, compared with 45.2% at both 24 and 48 months with residual MR 2+. “The difference between MR ≤1 and MR=2 was significant,” Dr. Buzzatti and colleagues said.

The researchers separately evaluated outcomes among those who had functional MR (FMR) and degenerative MR (DMR). In FMR, patients with MR 2+ had a higher risk profile at baseline because of a slightly higher rate of advanced heart disease; they typically had larger ventricles with larger mitral valves and greater pulmonary pressure than the ≤1 MR patients. “Notably, these features could have impaired the surgeon’s ability to achieve acute optimal MR reduction during the MitraClip procedure,” Dr. Buzzatti and coauthors said. “For sure, advanced left ventricle remodeling was a strong independent predictor of increased cardiac death.” The study authors could not draw a similar conclusion with DMR because only three patients in the group died of cardiac causes.

MR recurrence was “remarkably higher” in MR 2+ patients, compared with the MR ≤1 group with FMR and DMR, and MR 2+ developed in 21.4% of the FMR group within 30 days of the procedure. “This poor efficacy results in a population of patients who were supposed to have had a ‘procedural success’ is striking,” Dr. Buzzatti and coauthors noted.

Dr. Buzzatti and coauthor Dr. Paolo Denti disclosed receiving consultant fees from Abbott Vascular. Coauthor Dr. Fabio Barili disclosed receiving consultant fees from St. Jude Medical. The other coauthors had no relationships to disclose.

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