Mitral annulus calcification (MAC) affects between 8% and 23% of the population. It is more common in women and patients with renal insufficiency. This phenomenon is characterized by an increase in valvular annulus fibrosis, which can extend and affect the leaflets.
The presence of MAC is associated with valve regurgitation or stenosis, increasing mortality and hospitalizations due to heart failure.
It is important to understand this condition and the associated myocardial damage when making therapeutic decisions, especially in the case of percutaneous treatment.
Researchers conducted an analysis of 953 patients with MAC using color transthoracic Doppler echocardiography. Mitral valve dysfunction (MVD) was defined as mitral regurgitation ≥2+ and/or mitral stenosis with a mitral valve area (MVA) <2.0 m² and/or a mean gradient ≥4 mm Hg.
Patients were classified into five stages according to the presence of MAC and myocardial damage. Stage 0 (S0): MAC with MVD without myocardial damage. Stage 1 (S1): MAC with MVD and left ventricular remodeling. Stage 2 (S2): MAC with MVD and left atrial remodeling and/or atrial fibrillation. Stage 3 (S3): MAC with MVD, pulmonary hypertension and/or moderate or greater tricuspid regurgitation. Stage 4 (S4): MAC with MVD and right ventricular dysfunction
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Results showed that 1.5% of patients were in S0 (15), 1.4% in S1 (13), 52.4% in S2 (1499), 12.1% in S3 (115), and 32.6% in S4 (311).
Mean patient age was 76 years, and 54% of subjects were women. Additionally, 77.5% had hypertension, 69% had dyslipidemia, and 40% had coronary artery disease. Compared with patients in the lower stages, those in advanced stages had a higher prevalence of diabetes, atrial fibrillation, and renal impairment.
Left ventricular ejection fraction was significantly lower in patients in the advanced stages, and so was the mitral gradient.
The estimated 4-year survival was 84% (95% confidence interval [CI]: 68%-100%) for S0 and S1, 53% (95% CI: 48%-59%) for S2, 30% (95% CI: 21%-43%) for S3, and 26% (95% CI: 20%-33%) for S4. S2, S3, and S4 were statistically higher compared with S0 and S1. Heart failure hospitalizations in the same period were 19% (95% CI: 6%-40%) for patients in S0 and S1, 39% (95% CI: 34%-44%) in S2, 55% (95% CI: 44%-65%) in S3, and 54% (95% CI: 47%-60%) in S4. This was also significantly higher in S2, S3, and S4 compared with the other two stages.
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During follow-up, 120 patients required mitral valve intervention; 91 were treated surgically and the rest underwent percutaneous treatment. Advanced stages were associated with worse outcomes, regardless of whether MVD was due to regurgitation or stenosis.
Mortality predictors included age, diabetes, and a glomerular filtration rate <60 mL/min, while heart failure hospitalization predictors included stages S3 and S4, hypertension, and glomerular filtration rate <60 mL/min.
Conclusion
The use of this classification system for myocardial damage in patients with mitral annulus calcification and valve dysfunction demonstrates that advanced stages are associated with higher mortality rates.
Dr. Carlos Fava.
Member of the Editorial Board of SOLACI.org.
Original Title: Staging Extramitral Cardiac Damage in Mitral Annular Calcification.
Reference: Abdullah Al-Abcha, et al. JACC Cardiovasc Interv 2024;17:1577–1590.
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