Pôle Coeur-Thorax-Vaisseaux, Department of Cardiology (D.R., Y.B., M.K., C.T.), University Hospital Amiens, France.
Centre Universitaire de Recherche en Santé, Laboratoire MP3CV - EA 7517, Université de Picardie, Amiens, France (D.R., Y.B., S.M., C.T.).
Circ Cardiovasc Imaging. 2021 Aug;14(8):e012257. doi: 10.1161/CIRCIMAGING.120.012257. Epub 2021 Aug 17.
Myocardial contraction fraction (MCF) is a volumetric measure of myocardial shortening independent of left ventricular size and geometry. This multicenter study investigates the usefulness of MCF for risk stratification in low-gradient severe aortic stenosis with preserved ejection fraction.
We included 643 consecutive patients with low-gradient severe aortic stenosis with preserved ejection fraction in whom MCF was computed at baseline and analyzed mortality during follow-up.
Throughout follow-up with medical and surgical management (34.9 [16.1-65.3] months), lower MCF tertiles had higher mortality than the highest tertile. Eighty-month survival was 56±4% for MCF>41%, 41±4% for MCF 30% to 41%, and 40±4% for MCF<30% (<0.001). After comprehensive adjustment, mortality risk remained high for MCF 30% to 41% (adjusted hazard ratio, 1.53 [1.08-2.18]) and for MCF<30% (adjusted hazard ratio, 1.82 [1.24-2.66]) versus MCF>41%. The optimal MCF cutoff point for mortality prediction was 41%. Age, body mass index, Charlson index, peak aortic velocity, and ejection fraction were independently associated with mortality. MCF (χ to improve 10.39; =0.001), provided greater additional prognostic value over the baseline parameters than stroke volume (SV) index (χ to improve 5.41; =0.042), left ventricular mass index (χ to improve 2.15; =0.137), or global longitudinal strain (χ to improve 3.67; =0.061). MCF outperformed ejection fraction for mortality prediction. When patients were classified by SV index and MCF, mortality risk was low when SV index was ≥30 mL/m and MCF>41%, higher for patients with SV index ≥30 mL/m and MCF≤41% (adjusted hazard ratio, 1.47 [1.05-2.07]) and extremely high for patients with SV index <30 mL/m (adjusted hazard ratio, 2.29 [1.45-3.62]).
MCF is a valuable marker of risk in low-gradient severe aortic stenosis with preserved ejection fraction and could improve decision-making, especially in normal-flow low-gradient severe aortic stenosis with preserved ejection fraction.
心肌收缩分数（MCF）是一种独立于左心室大小和几何形状的心肌缩短的容积测量方法。这项多中心研究旨在探讨 MCF 在射血分数保留的低梯度重度主动脉瓣狭窄患者中的风险分层中的作用。
我们纳入了 643 例射血分数保留的低梯度重度主动脉瓣狭窄患者，在基线时计算 MCF 并分析随访期间的死亡率。
在接受药物和手术治疗的整个随访期间（34.9[16.1-65.3]个月），MCF 三分位较低的患者死亡率高于三分位较高的患者。MCF>41%、MCF 30%至 41%和 MCF<30%的 80 个月生存率分别为 56±4%、41±4%和 40±4%（<0.001）。在全面调整后，MCF 30%至 41%（调整后的危险比，1.53[1.08-2.18]）和 MCF<30%（调整后的危险比，1.82[1.24-2.66]）的死亡风险仍然较高，而 MCF>41%。MCF 用于预测死亡率的最佳截断点为 41%。年龄、体重指数、Charlson 指数、峰值主动脉速度和射血分数与死亡率独立相关。MCF（χ²改善 10.39；P=0.001）比 SV 指数（χ²改善 5.41；P=0.042）、左心室质量指数（χ²改善 2.15；P=0.137）或整体纵向应变（χ²改善 3.67；P=0.061）提供了更大的预后价值。MCF 比射血分数更能预测死亡率。当根据 SV 指数和 MCF 对患者进行分类时，SV 指数≥30mL/m 和 MCF>41%的患者死亡率较低，SV 指数≥30mL/m 和 MCF≤41%的患者（调整后的危险比，1.47[1.05-2.07]）的死亡率较高，SV 指数<30mL/m 的患者（调整后的危险比，2.29[1.45-3.62]）的死亡率极高。
MCF 是射血分数保留的低梯度重度主动脉瓣狭窄患者的一种有价值的风险标志物，可改善决策，特别是在射血分数保留的低流量低梯度重度主动脉瓣狭窄中。
