Valve Prosthesis Beats Repair for 2-Year Durability in Severe Ischemic MR

November 09, 2015

ORLANDO, FL ( UPDATED WITH COMMENTARY ) — Two-year outcomes from the National Institutes of Health (NIH)–sponsored Cardiac Surgery Clinical Research Network (CTSN) trial suggest that patients with severe ischemic mitral regurgitation (MR) fare just as well when the valve is repaired or replaced, at least when it comes to measures of left ventricular reverse remodeling and survival, but that replacing the mitral valve provides a more durable correction of MR[1].

Presenting the results of the CTSN trial here at the American Heart Association (AHA) 2015 Scientific Sessions, the researchers reported no significant difference in the mean left ventricular end-systolic volume index (LVESVI) among 251 patients randomized to mitral-valve repair or chordal-sparing mitral-valve replacement.

In addition, there was no mortality advantage with either approach. The 2-year mortality rate was 19.0% in the repair arm and 23.2% in the replacement group, a difference that was not statistically significant (hazard ratio 0.79; 95% CI 0.46–1.35).

Despite the equivocal results, investigators, including lead researcher Dr Daniel Goldstein (Montefiore Medical Center/Albert Einstein College of Medicine, New York), did observe significantly higher recurrence rates among patients who underwent surgical repair. At 2 years, 59% of patients in the repair arm and 3.8% in the replacement arm were diagnosed with moderate or severe MR (P<0.001).

"Recurrence was rather striking," said Goldstein during a press conference announcing the results. "Interestingly, most of the recurrences were moderate, were not severe."

This difference in MR translated into a significantly increased risk of heart failure at 2 years among patients undergoing mitral-valve repair (24.0% vs 15.2% in the repair and replacement arms, respectively; P=0.05) as well as an increased readmission rate to hospital for cardiovascular causes (48.3% vs 32.2%, respectively; P=0.01).

Dr Daniel Goldstein

"There was no difference in the total readmissions to the hospital between groups," said Goldstein. "However, if you look at just cardiovascular readmissions, there was a striking difference, with repair patients requiring many more heart-failure readmissions than replacement patients. What were those heart-failure readmissions for? They were for true heart failure or for the placement of an ICD or biventricular pacers, which in essence are also heart-failure readmissions because the people who are getting those technologies are people with advanced heart failure."

The bottom line, say investigators, is that the 2-year data reveal a divergence in clinical outcomes not evident at 1 year. The deficiency in the durability of correction of MR with surgical repair is "disconcerting," they add, noting that MR recurrence predisposes patients to heart failure, atrial fibrillation, increased hospitalizations, and other adverse outcomes.

The 2-year results are published November 9, 2015 in the New England Journal of Medicine to coincide with the late-breaking clinical-trials presentation. One-year outcomes presented at the AHA 2013 meeting and reported by heartwire from Medscape at that time.

Who Should Get Repair? Who Replacement?

Dr Alain Carpentier (Descartes University, Paris, France), one of the world leaders in mitral-valve repair, said the findings are particularly important for younger, less experienced surgeons. "If these results are confirmed, it means that the young surgeon with little experience in valve repair shouldn't feel guilty for replacing a valve because he or she will be certain that the result will be as good."

Valve repair, added Carpentier, is a "question of experience" and should be done only by surgeons with a large amount of clinical practice in the surgical technique. The present study is unique as the surgeons performing the procedure in BEAT-HF were experienced surgeons, a component of the trial that partially explains why repair and replace both fared as well in terms of the primary end point.

Speaking with the media, Goldstein said physicians who support valve repair believe it is associated with lower morbidity and mortality, noting that it results in the preservation of the entire mitral subvalvular apparatus. MR recurrence is a known problem, however, and this can lead to functional mitral stenosis if the ring is very small. Replacement, on the other hand, is associated with higher perioperative morbidity and mortality, but it does provide a more durable correction of MR.

Goldstein said that even though there was no difference in LVESVI at 2 years or in mortality either, recurrence is a factor that will weigh in a decision over whether or not to repair or replace the mitral valve. Right now, he is comfortable performing a mitral-valve replacement as first-line treatment in a majority of patients. "I think we still need to follow these patients a little longer, because you have to remember you have a prosthesis in there," he said. "The prosthesis can give you problems. There's thromboembolic complications, it can get infected, it can deteriorate and need rereplacement, so the balance of those issues awaits more time."

That said, in the absence of reliable predictors of a successful mitral-valve repair, surgical replacement of the mitral valve is a viable option. "Based on experience, I think a lot of people want to start thinking a little more liberally about replacing the valve in general just because of these data," he said. Optimal valve-replacement candidates would include individuals with a basal aneurysm or basal dyskinesia, he noted.

Goldstein reports grant support from the National Institutes of Health and consulting fees from Medtronic. Disclosures for the coauthors are listed on the journal website.

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