Mitral Annular Calcification and Its Severity in Relation to Left Atrial Reservoir Strain and a Non-Invasive Left Atrial Stiffness Index.

Purpose

Mitral annular calcification (MAC) is associated with atrial fibrillation and diastolic dysfunction, but its relationship with left atrial (LA) mechanics is poorly defined. The ratio of E/e' to LA reservoir strain (LASr) is a non-invasive surrogate of, not a direct measure of, LA stiffness. We assessed MAC and its severity against LASr and this LA stiffness index (LASI).

Methods

In this single-center cross-sectional study with prospective recruitment, 112 adults in sinus rhythm with ejection fraction ≥50% (58 with MAC, 54 age- and sex-similar controls) underwent two-dimensional speckle-tracking echocardiography. MAC was graded mild to severe; LASI was calculated as E/e' divided by LASr.

Results

LASr was lower (23.2 ± 7.8% vs. 26.7 ± 7.7%, p = 0.018) and LASI higher (0.57 ± 0.30 vs. 0.34 ± 0.20, p < 0.001) in the MAC group. In models excluding the index components, MAC severity was independently associated with higher LASI (β = 0.41, p < 0.001) and MAC presence with lower LASr (-3.6 points, p = 0.016). After clinical adjustment, each 0.1-unit LASI increase was associated with MAC (odds ratio 1.71, 95% CI[1.34-2.17]). LASI discriminated MAC with an area under the curve of 0.762 (0.674-0.851; cut-off 0.31, sensitivity 79%, specificity 63%), which did not differ from E/e' (p = 0.52) or LA volume index (p = 0.48).

Conclusion

MAC and its severity were associated with impaired LA reservoir function and a higher non-invasive stiffness index. The index did not discriminate MAC better than its simpler components, so these cross-sectional findings are hypothesis-generating.