Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China; Department of Medicine, University of Chicago, Chicago, Illinois.
Department of Medicine, University of Chicago, Chicago, Illinois.
Am J Cardiol. 2022 Jul 1;174:143-150. doi: 10.1016/j.amjcard.2022.02.022. Epub 2022 Apr 26.
Quantification of myocardial perfusion reserve (MPR) using vasodilator stress cardiac magnetic resonance is increasingly used to detect coronary artery disease. However, MPR can also be altered because of changes in microvascular function. We aimed to determine whether MPR can distinguish between ischemic cardiomyopathy (IC) secondary to coronary artery disease and non-IC (NIC) with microvascular dysfunction and no underlying epicardial coronary disease. A total of 60 patients (mean age 65 ± 14 years, 30% women), including 31 with IC and 29 with NIC, were identified from a pre-existing vasodilator stress cardiac magnetic resonance registry. Short-axis cine slices were used to measure left ventricular ejection fraction (LVEF) using the Simpson method of disks. MPR index (MPRi) was determined from first-pass myocardial perfusion images during stress and rest using the upslope ratio, normalized for the arterial input and corrected for rate pressure product. Patients in both groups were divided into subgroups of LVEF ≤35% and LVEF >35%. Differences in MPRi between the subgroups were examined. MPRi was moderately correlated with LVEF in patients with NIC (r = 0.53, p = 0.03), whereas the correlation in patients with IC was lower (r = 0.32, p = 0.22). Average LVEF in NIC and IC was 34% ± 8% and 35% ± 8%, respectively (p = 0.63). MPRi was not significantly different in IC compared with NIC (1.17 [0.88 to 1.61] vs 1.23 [1.07 to 1.66], p = 0.41), including the subgroups of LVEF (IC: 1.20 ± 0.56 vs NIC: 1.15 ± 0.24, p = 0.75 for LVEF ≤35% and IC: 1.35 ± 0.44 vs NIC: 1.58 ± 0.50, p = 0.19 for LVEF >35%). However, MPRi was significantly lower in patients with LVEF ≤35% compared with those with LVEF>35% (1.17 ± 0.40 vs 1.47 ± 0.47, p = 0.01). Similar difference between LVEF groups was noted in the patients with NIC (1.15 ± 0.24 vs 1.58 ± 0.50, p = 0.006) but not in the patients with IC (1.20 ± 0.56 vs 1.35 ± 0.44, p = 0.42). MPRi can be abnormal in the presence of left ventricular dysfunction with nonischemic etiology. This is a potential pitfall to consider when using this approach to detect ischemia because of epicardial coronary disease using myocardial perfusion imaging.
使用血管扩张剂应激心脏磁共振评估心肌灌注储备（MPR）的方法越来越多地用于检测冠状动脉疾病。然而，由于微血管功能的改变，MPR 也可能发生改变。我们旨在确定 MPR 是否可以区分冠状动脉疾病引起的缺血性心肌病（IC）和无潜在心外膜冠状动脉疾病的非缺血性心肌病（NIC）伴微血管功能障碍。总共从现有的血管扩张剂应激心脏磁共振注册中心确定了 60 名患者（平均年龄 65 ± 14 岁，30%为女性），包括 31 名 IC 患者和 29 名 NIC 患者。使用 Simpson 磁盘法在短轴电影片中测量左心室射血分数（LVEF）。使用上升斜率比，在应激和休息期间通过首过心肌灌注图像来确定 MPRi 指数（MPRi），并为动脉输入和心率血压乘积校正进行归一化。在两组患者中，均根据 LVEF 将患者分为 LVEF≤35%和 LVEF＞35%亚组。检查了亚组之间 MPRi 的差异。在 NIC 患者中，MPRi 与 LVEF 中度相关（r=0.53，p=0.03），而在 IC 患者中的相关性较低（r=0.32，p=0.22）。NIC 和 IC 中的平均 LVEF 分别为 34%±8%和 35%±8%（p=0.63）。与 NIC 相比，IC 中的 MPRi 没有显著差异（1.17[0.88 至 1.61]与 1.23[1.07 至 1.66]，p=0.41），包括 LVEF 亚组（IC：1.20±0.56 与 NIC：1.15±0.24，p=0.75 对于 LVEF≤35%和 IC：1.35±0.44 与 NIC：1.58±0.50，p=0.19 对于 LVEF＞35%）。然而，与 LVEF＞35%的患者相比，LVEF≤35%的患者 MPRi 明显更低（1.17±0.40 与 1.47±0.47，p=0.01）。在 NIC 患者中也观察到 LVEF 组之间存在类似的差异（1.15±0.24 与 1.58±0.50，p=0.006），但在 IC 患者中则没有（1.20±0.56 与 1.35±0.44，p=0.42）。当使用心肌灌注成像检测心外膜冠状动脉疾病引起的缺血时，非缺血性病因引起的左心室功能障碍时 MPRi 可能异常。这是使用这种方法检测缺血时需要考虑的潜在陷阱。
