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Fate of Moderate Functional Mitral Regurgitation after Aortic Valve Replacement: Is Concomitant Mitral Valve Repair Necessary?
C. K. Wan, Z. Li, T. A. Orszulak, R. C. Daly, H. V. Schaff, T. M. Sundt. Mayo Clinic, Rochester, MN,
BACKGROUND:
The appropriate management of moderate mitral regurgitation(MR) in the setting of severe aortic valve disease among patients coming to aortic valve replacement(AVR) remains undefined. We therefore reviewed our experience with this patient subset to determine predictors of residual MR and patient survival after AVR.
METHODS:
We retrospectively identified 190 consecutive patients undergoing AVR with at least moderate(≥grade 2) concomitant functional MR from 1993-2006. Patients with identifiable structural valve abnormalities or significant coronary artery disease were excluded. Follow-up echocardiographic data were available at discharge for 88% of patients, and at midterm(3.0±2.6years) for 57% of survivors. Late survival information was obtained from chart review and social security database for 94% of patients(3.8±3.6years). Aortic stenosis(AS) was predominant in 158(83%) patients, aortic regurgitation(AR) in 25(13%), and mixed AS/AR in 7(4%). Mean age was 74±11years, 45% were male, and 148(78%) in NYHA III-IV. The mean preoperative ejection fraction(LVEF) was 48±17%, with LVEF ≤40% in 41%. MR grade 2, 3 and 4 was present in 170(89%), 19(10%), and 1(1%) patients respectively. Univariate and multivariate analyses for decreased survival and residual MR were performed. Ninety-one patients were case-matched to age, gender, and LVEF with patients undergoing AVR without MR.
RESULTS:
Early mortality was 6%(n=10). At dismissal and mid-term follow-up respectively, MR was improved in 76% and 67%, unchanged in 23% and 30%, and worsened only in 1% and 3%. No reoperations for MR were performed. Postoperatively, 81(89%) were NYHA I-II and 10(11%) NYHA III. By univariate analysis, improved MR at dismissal was associated with younger age, male gender, higher mean aortic valve gradient, higher body surface area, lower preoperative TR grade, lower pre-bypass MR grade and larger aortic prosthesis. Improved MR at follow-up was associated with absence of cerebrovascular disease(CVD), presence of preoperative heart failure symptoms, lower LVEF, lower preoperative systolic blood pressure, increased left ventricular end-diastolic dimension(LVEDD) and decreased septal thickness. Independent predictors of improved MR at dismissal by multivariate analysis were lower grades of preoperative TR and pre-bypass MR. Predictors of lower MR at mid-term follow-up were absence of CVD, and lower LVEF. Survival at 5 and 10 years was 68.0% and 42.4%, respectively(p<0.001 vs. age-/gender-matched general population). Independent predictors of decreased survival were increased age, diabetes, and dialysis-dependence. In a case-matched analysis, however, survival of 91 patients from this cohort did not differ from patients undergoing AVR without MR(p=0.33).
CONCLUSIONS:
Moderate functional MR improves in most patients after AVR, This improvement is persistent at midterm follow-up. Functional status of most patients is also improved. Although patients with concomitant moderate functional MR undergoing AVR have decreased survival compared to general population, this difference is likely due to impaired ventricular function. This suggests mitral valve intervention for moderate functional MR is not likely to improve outcome.
 
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