Similar survival observed for transcatheter, surgical mitral valve repair

Transcatheter and surgical mitral valve repair were both associated with 1-year survival rates of around 85% in a cohort of patients at high risk for surgery.

In the study, researchers compared transcatheter mitral valve repair using the MitraClip (Abbott Vascular) with mitral valve surgery and conservative treatment in a cohort of patients with symptomatic severe mitral regurgitation (MR) who were in a high surgical risk category based on log EuroSCORE results or other relevant risk factors.

The analysis included 139 consecutive patients in the transcatheter repair cohort. The 53 patients in the surgery cohort and 59 patients in the conservative therapy cohort were identified retrospectively.

Patients in the transcatheter group demonstrated a higher log EuroSCORE than patients in the other two groups (23.9 ± 16.1% vs. surgical, 14.2 ± 8.9%; conservative, 18.7 ± 13.2%; P<.0001).

Rates of LV ejection fraction were higher in the surgery group (43.9 ± 14.4%; P=.003) than in the transcatheter repair group (36.8 ± 15.3%) and the conservatively treated group (34.5 ± 16.5%).

Survival outcomes at 1 year were 85.8% for transcatheter repair and 85.2% for surgery compared with 67.7% for patients treated conservatively. Two- and 3-year follow-up results demonstrated a similar trend for survival.

Results of an adjusted analysis that weighted propensity score and risk factors indicated that survival outcomes remained higher in the transcatheter repair group (HR=0.41; 95% CI, 0.22-0.78) and the surgical group (HR=0.52; 95% CI, 0.30-0.88) than those reported in the conservatively treated group. No difference, however, was reported for survival between the transcatheter repair group and the surgical group in terms of survival (HR=1.25; 95% CI, 0.72-2.16).

Robert O. Bonow

In an accompanying editorial, Robert O. Bonow, MD, MS, with the Northwestern University Feinberg School of Medicine, Chicago, wrote that this study offers new insight into the survival advantage of surgical and transcatheter intervention compared with medical therapy in this patient cohort. However, he suggested that the dataset was somewhat unique. “This study was not designed specifically to address this issue, because it included a broad spectrum of high-risk patients with both primary and secondary forms of MR,” he wrote.

Because of this, Bonow wrote that the patient population represented a “conglomeration” of high-risk cohorts. “The apples and oranges of this patient admixture create uncertainties in attempts to fully interpret the data in previous studies, as well as in the current study,” he wrote. “However, because the majority of patients studied by Swaans et al. had functional MR, with several others deemed to have ‘mixed’ functional plus degenerative MR, the results do potentially address the ongoing issues regarding when to intervene in secondary, functional MR.”

There are several limitations of the study, according to Bonow, including: the fact that historical patients were used as controls; differences in baseline characteristics between the conservatively treated group and the other groups; and the lack of specification with regards to the details of medical therapy. “The very high mortality rate of the conservative group (one-third died in the first year) does raise the question of aggressiveness of medical management,” he wrote. “If there was under-treatment of these patients, the results showing better outcome with surgical or transcatheter intervention are self-fulfilling.”

Bonow noted that analyzing survival data in mitral valve interventions has traditionally been “fraught with difficulty,” and that the survival benefits of surgery and transcatheter intervention in high-risk patients remain difficult to compare.

“Thus, the current data do not define the role of mitral valve intervention in secondary MR,” he concluded. “These data do underscore the need for prospectively designed clinical trials of mitral valve intervention (surgical or transcatheter) versus [guidelines-directed medical therapy] in patients with LV dysfunction and secondary MR.”

For more information:

Bonow RO. J Am Coll Cardiol Intv. 2014;7:882-884.

Swaans MJ. J Am Coll Cardiol Intv. 2014;7:875-881.

Disclosure: The researchers report financial disclosures with Abbott Vascular. Bonow reports no relevant financial disclosures.