Similar Long-term Benefits With Mitral Valve Repair, Replacement for Ischemic MR

DALLAS, TX—Mitral-valve repair results in similar left ventricular (LV) reverse remodeling and survival outcomes compared with mitral-valve replacement in patients with ischemic mitral regurgitation (MR) at 12 months, according to late breaking clinical trial results presented November 18, 2013, at the annual American Heart Association Scientific Sessions and published simultaneously in the New England Journal of Medicine. However, replacement provided a more durable correction of MR.

For the CTSN SMR trial, Michael A. Acker, MD, of the University of Pennsylvania School of Medicine (Philadelphia, PA), and colleagues randomized 251 patients with severe ischemic MR and CAD to surgery to repair (n = 126) or replace (n = 125) the mitral valve at 22 hospitals from 2009-2012. The degree of LV reverse remodeling at 12 months (primary endpoint) was assessed by left ventricular end systolic volume index (LVESVI) using TTE.

Little Difference Between Repair, Replacement

At 1 year, the mean LVESVI among surviving patients was 54.6 ± 25.0 ml per square meter of body-surface area in the repair group and 60.7 ± 31.5 ml per square meter in the replacement group (mean change from baseline -6.6 and -6.8 ml per square meter, respectively).

Mortality was similar between the repair and replacement groups (14.3% vs. 17.6%; HR 0.79; 95% CI 0.42-1.47; log-rank P = 0.45). There was no difference in LVESVI after adjustment for death (P = 0.18). Similarly, there were no differences in the rate of a composite of MACCE (HR 0.91; 95% CI 0.58-1.42; log-rank P = 0.68) or any of its components at 12 months.

Still, the rate of moderate or severe MR recurrence at 12 months was higher in the repair group than in the replacement group (32.6% vs. 2.3%; P < 0.001). Within 1 year, 3 patients, all in the repair group, underwent mitral-valve reoperation (P = 0.25).

Quality of life and functional status as assessed by the Minnesota Living with Heart Failure questionnaire showed a reduction in heart-failure symptoms from baseline of 46.9% in the repair group and 61.2% in the replacement group. Similarly, there were 16.6% and 18.4% physical health improvements over baseline in the repair and replacement groups, respectively, as seen on the Medical Outcomes Study 12-Item Short Form Health Survey (SF-12).

LVEF was 41.5 ± 10.8% in the repair group and 37.8 ± 12.5% in the replacement group. The mean duration of index hospitalization was similar in the repair and replacement groups (17.3 ± 11.4 vs. 16.7 ± 10.4 days; P = 0.84). The mean length of stay after surgery was 11.5 ± 9.0 days in the repair group and 11.9 ± 8.6 days in the replacement group, with no differences in rates of readmission.

Support for Replacement Growing

Dr. Acker said that a limitation of the study was the lack of a revascularization-only arm, but this is currently being studied in an ongoing trial. Additionally, the primary endpoint only measures LV remodeling, and not a clinical endpoint. However, he observed, “abundant evidence correlates LVESVI with clinical outcomes.”

Patients in the study will be followed out to 2 years, Dr. Acker reported. “Additional follow-up may provide insight about predictors and clinical impact of mitral regurgitation recurrence optimizing therapeutic decisions for individual patients,” he said.

When asked if he would switch his clinical strategy tomorrow, Dr. Acker said he would advocate for replacement, although the needs of the individual patient should be taken into account, especially with young vs. old patients and those with large hearts.

Discussing the study, Timothy J. Gardner, MD, of Christiana Care Health System (Wilmington, DE), said “there is a clear bias among many cardiac surgeons and some cardiologists that repair is preferable to replacement, even for patients with severe [ischemic mitral regurgitation]. The present trial results clearly refute this assumption.”

Study Details

Replacement included complete preservation of the subvalvular apparatus. The technique of preservation, type of prosthetic valve, and technique of suture placement were chosen according to the preference of the surgeon, as was the type of annuloplasty ring in the repair group. The protocol mandated the use of an approved rigid or semirigid complete annuloplasty ring, which was downsized for the annulus diameter. All patients were to receive guideline-directed medical therapy, including aspirin, lipid-lowering agents, beta-blockers, and angiotensin-converting-enzyme inhibitors, as well as cardiac-resynchronization therapy.

 


Source:
Acker MA, Parides MK, Perrault LP, et al. Mitral-valve repair versus replacement for severe ischemic mitral regurgitation. N Engl J Med. 2013;Epub ahead of print.

 

 

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Disclosures
  • The study was funded by the National Institutes of Health and the Canadian Institutes of Health.
  • Dr. Acker reports serving as a consultant to Thoratec Inc.
  • Dr. Gardner reports no relevant conflicts of interest.

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