Mitral annulus calcification: determinants of repair feasibility, early and late surgical outcome

OBJECTIVE: The aim of this study was to determine the factors influencing the feasibility of valve repair and the surgical outcome in patients with mitral annulus calcification. METHODS: In 124 patients with mitral annulus calcification undergoing surgery, two entities were distinguished: Barlow disease (myxomatous leaflets, n=60) and fibroelastic deficiency (FED) (normal leaflets, n=64). The calcification score was lower (1.9 vs 2.8); the annulus was more dilated (ring 35 vs 32 mm) and ruptured chordae were more frequent (77% vs 37%) in Barlow than in FED (p<0.001). The clinical profile was different: age (60+/-14 vs 73+/-8 years, p<0.001), systemic hypertension (22% vs 70%, p<0.001), chronic renal insufficiency (5% vs 22%, p<0.01), cancer (7% vs 25%, p<0.01). Multifocal atherosclerosis was less frequent in Barlow than in FED: carotid disease (17% vs 54%, p<0.001), aortic atheroma (21% vs 51%, p<0.001) and coronary disease (22% vs 56%, p<0.01). Echocardiography showed two different patterns in Barlow and FED: aortic valve stenosis (1.7% vs 31%), left atrial diameter (54 vs 49 mm), left ventricular end-diastolic diameter (62 vs 54 mm), interventricular septal thickness (11 vs 13 mm), and systolic pulmonary pressure (40 vs 56 mmHg), respectively (p<0.001). Bacterial endocarditis was observed in 24 cases (19%). RESULTS: The surgical technique was a valve repair in 68% and a replacement in 32%. The repair rate depended upon the extent of annulus calcifications (p<0.001) and the type of degenerative disease (95% vs 44% in Barlow and FED p<0.001). In-hospital mortality was 14% (Barlow: 5% vs FED: 23%, p<0.01). The mean follow-up was 50+/-41 months. Overall 5-year year survival was 76% (Barlow: 90% vs FED: 64%, p<0.001) and survival free from cardiac event was 69% at 5 years (Barlow: 87% vs FED: 52%, p<0.001). Five-year survival was higher following repair than replacement (84% vs 64% p<0.001). Chronic renal insufficiency and bacterial endocarditis were two predictors of early and late death (p<0.01). CONCLUSIONS: The aetiopathogeny of the degenerative mitral disease responsible for annulus calcifications corresponded to distinct anatomical, clinical and echographic patterns. It was a main determinant of repair feasibility, early and late surgical outcome.