背景：冠状动脉微血管功能障碍在患有淀粉样蛋白轻链（AL）心脏淀粉样变性（AL-CA）的患者中非常普遍。这项研究的目的是阐明使用3T心血管磁共振（CMR）进行首过灌注成像评估正常人和AL-CA患者左心室（LV）局部心肌微血管功能差异的可行性。淀粉样变性患者分为收缩功能受损[LV射血分数（LVEF）<50％]和收缩功能保留的患者。
方法：总共，32例经活检证实的AL-CA，包括11例收缩功能障碍的AL-CA患者，21例收缩功能保留的AL-CA患者，和25个健康的受试者，进行CMR检查。左心室局部心肌灌注参数包括上坡，比较三组患者达到最大信号强度的时间(TTM)和最大信号强度(MaxSI).进行了接收器操作特征分析，以确定灌注参数是否可用于区分AL-CA患者和正常人之间的局部心肌微血管。
结果：AL-CA患者的首过灌注上升斜率和MaxSI显著降低，与正常人相比，TTM升高（均P<0.01）。与AL-CA和保留LVEF的患者相比，患有AL-CA和收缩功能受损的患者在基底的TTM更长（47.05±16.59vs.39.68±19.11；P=0.002）和中室（44.61±16.34vs.37.74±18.25；P=0.002）段；基底上坡较低（2.41±1.32vs.3.60±1.68;P<0.0001),中室（2.82±1.34vs.4.15±2.02;P<0.0001),和根尖（3.71±1.38vs.4.97±2.55；P=0.004）段；和较低的MaxSI（31.67±15.23vs.37.96±11.15；P<0.0001）在基底段。ROC曲线分析表明，第一遍上坡，TTM,和MaxSI可用作区分收缩功能保留或受损的AL-CA患者与正常受试者之间微循环的指标。
结论：正常受试者左心室局部心肌微血管功能的差异，有收缩功能障碍的AL-CA患者，可以使用首过灌注CMR监测收缩功能保留的AL-CA患者。
BACKGROUND: Coronary microvascular dysfunction is highly prevalent in patients with amyloid light-chain (AL) cardiac amyloidosis (AL-CA). The aim of this study was to clarify the feasibility of first-pass perfusion imaging using 3 T cardiovascular magnetic resonance (CMR) for evaluating the difference in left ventricular (LV) regional myocardial microvascular function among normal subjects and in patients with AL-CA. The amyloidosis patients were classified into those with impaired systolic function [LV ejection fraction (LVEF) < 50 %] and those with preserved systolic function.
METHODS: In total, 32 patients with biopsy-proven AL-CA, including 11 AL-CA patients with systolic dysfunction, 21 AL-CA patients with preserved systolic function, and 25 healthy subjects, underwent CMR examination. LV regional myocardial perfusion parameters included upslope, time to maximum signal intensity (TTM) and max signal intensity (MaxSI) were compared among the three patient groups. Receiver operating characteristic analysis was performed to determine whether perfusion parameters could be used in discriminating regional myocardial microvascularity between AL-CA patients and normal subjects.
RESULTS: The patients with AL-CA had significantly reduced first-pass perfusion upslope and MaxSI, and increased TTM compared with the normal subjects (all P < 0.01). Compared with the patients with AL-CA and preserved LVEF, the patients with AL-CA and impaired systolic function had a longer TTM in the basal (47.05 ± 16.59 vs. 39.68 ± 19.11; P = 0.002) and mid-ventricular (44.61 ± 16.34 vs. 37.74 ± 18.25; P = 0.002) segments; lower upslope in the basal (2.41 ± 1.32 vs. 3.60 ± 1.68; P < 0.0001), mid-ventricular (2.82 ± 1.34 vs. 4.15 ± 2.02; P < 0.0001), and apical (3.71 ± 1.38 vs. 4.97 ± 2.55; P = 0.004) segments; and lower MaxSI (31.67 ± 15.23 vs. 37.96 ± 11.15; P < 0.0001) in the basal segment. The ROC curve analysis revealed that the first-pass upslope, TTM, and MaxSI may be used as indicators for differentiating microcirculation between AL-CA patients with preserved or impaired systolic function and normal subjects.
CONCLUSIONS: The differences in LV regional myocardial microvascular function among normal subjects, AL-CA patients with systolic dysfunction, and AL-CA patients with preserved systolic function can be monitored using first-pass perfusion CMR.
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