Background

Aging is associated with progressive loss of muscle mass, as well as replacement of muscle with fat and fibrous tissue. We studied the contribution of muscle fat content, a surrogate marker of biological aging, to frailty and Length of Hospital Stay (LOS) following Transcatheter Aortic Valve Replacement (TAVR).

Methods

We evaluated 415 patients who underwent TAVR from February 2012 to December 2016 at Mayo Clinic, MN, USA. Densities between −190 to −30 Hounsfield Units within the abdominal muscle area were determined as muscle fat. Muscle Fat Index (MFI) was defined as muscle fat mass divided by height squared. LOS was considered as the primary outcome. Stepwise multivariable linear regression was used to identify the predictors of LOS.

Results

Mean age ± SD of the study population was 81.2 ± 9.6 years and 58.07% were male. Seventy-two patients (17.35%) had frailty. Median (IQR) LOS was 4 (3–6) days. MFI was higher in patients with frailty (median (IQR); 18.1 [13.8–24.2] vs 14.4 [10.6–18.7], p < 0.001) and was positively correlated with LOS (r = 0.129, p = 0.009). In multivariable analysis of predictors of LOS, MFI (β = 0.06, p = 0.022), pre-TAVR atrial fibrillation/flutter (β = 0.5, p = 0.015), and post-TAVR complications (β = 0.91, p < 0.001) were directly, and femoral access route (β = −1.13, p < 0.001) and pre-TAVR hemoglobin (β = −0.35, p = 0.002) were inversely associated with LOS.

Conclusions

MFI can be determined from pre-TAVR CT scans and is a novel predictor of LOS following TAVR. This objective indicator can potentially be used in a pre-TAVR clinic to plan for rehabilitation programs in selected patients.

中文翻译：

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肌肉脂肪指数与高危患者经导管主动脉瓣置换术后的虚弱和住院时间相关

背景

衰老与肌肉质量的逐渐减少以及用脂肪和纤维组织替代肌肉有关。我们研究了经导管主动脉瓣置换术 (TAVR) 后肌肉脂肪含量（生物衰老的替代标志物）对虚弱和住院时间 (LOS) 的影响。

方法

我们评估了 2012 年 2 月至 2016 年 12 月在美国明尼苏达州梅奥诊所接受 TAVR 的 415 名患者。腹部肌肉区域内-190至-30 Hounsfield单位之间的密度被确定为肌肉脂肪。肌肉脂肪指数（MFI）定义为肌肉脂肪量除以身高的平方。LOS被认为是主要结果。逐步多元线性回归用于识别 LOS 的预测因子。

结果

研究人群的平均年龄 ± SD 为 81.2 ± 9.6 岁，58.07% 为男性。72名患者（17.35%）身体虚弱。中位数 (IQR) LOS 为 4 (3-6) 天。虚弱患者的 MFI 较高（中位数 (IQR)；18.1 [13.8-24.2] vs 14.4 [10.6-18.7]，p  < 0.001）并且与 LOS 呈正相关（r  = 0.129，p  = 0.009）。在 LOS、MFI（β  =  0.06，p  = 0.022）、TAVR 前房颤/扑动（β  =  0.5，p  = 0.015）和 TAVR 后并发症（β  =  0.91，p  < 0.001）的多变量分析中直接和股骨入路（β = - 1.13, p < 0.001) 和 TAVR 前血红蛋白 ( β  = - 0.35, p  = 0.002) 与 LOS 呈负相关。

结论

MFI 可以从 TAVR 前 CT 扫描中确定，并且是 TAVR 后 LOS 的新预测指标。该客观指标可潜在地用于 TAVR 前的诊所，以计划选定患者的康复计划。