BACKGROUND The basis for abnormal microvascular flow responses to demand stress in coronary artery disease (CAD) is affected by resistance changes at both the epicardial stenosis level and within the downstream capillary network. We hypothesized that abnormal microvascular perfusion (MVP) responses during demand stress in patients with intermediate coronary stenoses occur when fractional flow reserve (FFR) across the epicardial stenosis is normal, because of increased microvascular resistance. METHODS In 49 coronary arteries of 41 patients with intermediate stenoses (40%-80%) who were referred for both coronary angiography and demand stress MVP assessment, invasive coronary hemodynamics were obtained across the stenosis to measure FFR, coronary flow reserve (CFR), and hyperemic microvascular resistance (HMR) during adenosine infusion. MVP in each coronary artery territory (CAT) during demand stress was evaluated by an independent expert reviewer blinded to clinical and angiographic data. RESULTS Thirty-four of the 49 CATs with intermediate stenoses exhibited abnormal MVP. Although the sensitivity of MVP was high for detecting abnormal FFR (100%), FFR < 0.8 was observed in only 15 of the 34 vessels that exhibited abnormal MVP (positive predictive value 44%). However, HMR was abnormal in 32 of 34 vessels (94%) with abnormal MVP (positive predictive value, 94%). CONCLUSIONS Although abnormal MVP has high sensitivity for detecting abnormal FFR, MVP is frequently abnormal when FFR is normal. In a large percentage of these patients, invasive assessments of microvascular resistance are abnormal.

中文翻译：

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毛细管血流评估与实时心肌灌注超声心动图与有创微血管和心外膜评估的关系。

背景技术对心外膜狭窄水平和下游毛细血管网内的阻力变化影响对冠状动脉疾病（CAD）中的需求压力的异常微血管流动响应的基础。我们假设，由于微血管阻力增加，跨心外膜狭窄的部分血流储备（FFR）正常时，中度冠状动脉狭窄患者在需求压力期间会出现异常的微血管灌注（MVP）反应。方法在41例中度狭窄患者（40％-80％）的49例冠状动脉中，他们同时接受了冠状动脉造影和需求压力MVP评估，在狭窄部位获得了侵入性冠状动脉血流动力学以测量FFR，冠状动脉血流储备（CFR）和腺苷输注过程中的充血性微血管阻力（HMR）。由对临床和血管造影数据不知情的独立专家评审对需求压力期间每个冠状动脉区域（CAT）的MVP进行了评估。结果49例中度狭窄的CAT中有34例表现出MVP异常。尽管MVP检测异常FFR的敏感性很高（100％），但在34个表现出异常MVP的血管中只有15个观察到FFR <0.8（阳性预测值44％）。但是，在34例血管中，有32例的HMR异常（94％），MVP异常（阳性预测值，为94％）。结论尽管异常MVP对异常FFR具有很高的检测灵敏度，但当FFR正常时，MVP常常是异常的。在这些患者中，有很大比例的微血管阻力的侵入性评估是异常的。