Akhiyat Nadia, Anand Vidhu, Kumar Vinayak, Ryu Alexander, Gibbons Raymond, Borlaug Barry A, Chandrasekaran Krishnaswamy, Abou Ezzeddine Omar, Anavekar Nandan
Division of Cardiology, Department of Medicine, Mayo Clinic, Rochester, MN, USA.
Division of Hospital Internal Medicine, Department of Medicine, Mayo Clinic, Rochester, MN, USA.
Int J Cardiol Heart Vasc. 2024 Oct 15;55:101525. doi: 10.1016/j.ijcha.2024.101525. eCollection 2024 Dec.
Amyloid light chain (AL) amyloidosis is a systemic disease that can cause restrictive cardiomyopathy (AL-CM). Current imaging techniques are not sensitive to detect myocardial dysfunction in AL-CM. We sought to evaluate role of a novel marker of myocardial dysfunction (myocardial function index, MFI) obtained using changes in left ventricular (LV) blood pool and myocardial volume in diastole and systole.
Consecutive patients diagnosed with AL-CM who had underwent cardiac MRI between 2001-2017 were identified and compared to healthy individuals. Two independent operators used cardiac MRI to perform epicardial and endocardial tracings in systole and diastole to obtain myocardial volume in diastole (MVd) and myocardial volume in systole (MVs). Changes in myocardial volumes during the cardiac cycle were measured to calculate the MFI by . Multivariable analysis was performed to evaluate predictors of all-cause mortality and survival was evaluated using Kaplan Meier analysis.
Patients with AL-CM (n = 129, 61 ± 10 years, 32 % women) were older and more likely to be men compared to the normal cohort (n = 101, 39 ± 15 years, 61 % women). MFI was lower in patients with AL-CM (19 % [15; 23] vs 38 % [35; 41], p < 0.001) and MFI < 30 % discriminated between AL-CM with 92 % sensitivity and 100 % specificity (AUC 0.98, p < 0.001). Higher MFI was independently associated with survival even after adjusting for conventional prognostic biomarkers of AL-CM (HR 0.02, 95 % CI 2.23 *104 - 0.24, p < 0.05). Two independent operators demonstrated high intra and inter-rater correlation in measurements used to calculate MFI.
MFI is a novel metric for assessing LV function. It is abnormal in patients with AL-CM and may play a role in risk stratification.
淀粉样轻链（AL）淀粉样变性是一种可导致限制性心肌病（AL-CM）的全身性疾病。目前的成像技术对检测AL-CM中的心肌功能障碍并不敏感。我们试图评估利用舒张期和收缩期左心室（LV）血池及心肌体积变化获得的一种新型心肌功能障碍标志物（心肌功能指数，MFI）的作用。
确定2001年至2017年间接受心脏磁共振成像（MRI）检查且被诊断为AL-CM的连续患者，并与健康个体进行比较。两名独立操作人员利用心脏MRI在收缩期和舒张期进行心外膜和心内膜描记，以获得舒张期心肌体积（MVd）和收缩期心肌体积（MVs）。测量心动周期中心肌体积的变化，通过……计算MFI。进行多变量分析以评估全因死亡率的预测因素，并使用Kaplan-Meier分析评估生存率。
与正常队列（n = 101，39±15岁，61%为女性）相比，AL-CM患者（n = 129，61±10岁，32%为女性）年龄更大，男性比例更高。AL-CM患者的MFI较低（19% [15；23] 对38% [35；41]，p < 0.001），MFI < 30%对AL-CM的鉴别灵敏度为92%，特异度为100%（曲线下面积0.98，p < 0.001）。即使在调整了AL-CM的传统预后生物标志物后，较高的MFI仍与生存率独立相关（风险比0.02，95%置信区间2.23×10⁻⁴ - 0.24，p < 0.05）。两名独立操作人员在用于计算MFI的测量中显示出较高的评分者内和评分者间相关性。
MFI是评估左心室功能的一种新型指标。它在AL-CM患者中异常，可能在风险分层中起作用。
