OBJECTIVE Inducible myocardial ischemia is influenced by contributions of both the epicardial artery and the coronary microcirculation. Experimental studies have found adverse microcirculatory remodeling to occur downstream of severe coronary stenoses. Coronary physiology studies in patients contradict the experimental findings, as the minimal microvascular resistance is not modified by stenoses. The objective was to determine whether microcirculatory remodeling occurs downstream of coronary stenoses in the human coronary circulation. Approach and Results: Myocardium corresponding to 115 coronary arteries of 55 deceased patients was investigated. Histopathologic staining of the microcirculation was performed using antibodies against SMA-α (smooth muscle actin-α) and CD31, to stain arterioles and capillaries, respectively. The following parameters were analyzed: ratio between lumen and vesel area, ratio between lumen and vessel diameter (both ratios for arterioles of <40, 40-100, and 100-200 µm diameter), arteriolar density, and capillary density. From the 55 patients, 32 pairs of an unobstructed coronary artery and a coronary artery with a stenosis were formed. No statistically significant differences between any of the microcirculatory parameters were found. A confirmatory unpaired analysis compared 3 groups: (1) coronary arteries in patients without coronary artery disease (n=53), (2) unobstructed coronary arteries in patients with a stenosis in one of the other coronary arteries (n=23), and (3) coronary stenoses (n=39). No statistically significant differences were observed between the groups. CONCLUSIONS The microcirculation distal to noncritical stenoses does not undergo structural remodeling in the human coronary circulation.

中文翻译：

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冠状动脉狭窄对微循环重塑的下游影响：组织病理学研究。

目的诱导性心肌缺血受心外膜动脉和冠状动脉微循环的影响。实验研究发现不良的微循环重塑发生在严重的冠状动脉狭窄的下游。患者的冠脉生理学研究与实验结果相矛盾，因为最小的微血管阻力不会被狭窄改变。目的是确定微循环重塑是否发生在人冠状动脉循环中冠状动脉狭窄的下游。方法和结果：调查了55例死者的115个冠状动脉对应的心肌。使用针对SMA-α（平滑肌肌动蛋白-α）和CD31的抗体分别对小动脉和毛细血管进行染色，对微循环进行组织病理学染色。分析了以下参数：管腔与血管面积之间的比率，管腔与血管直径之间的比率（直径<40、40-100和100-200 µm的小动脉比率），小动脉密度和毛细血管密度。从55名患者中，形成32对畅通的冠状动脉和具有狭窄的冠状动脉。没有发现任何微循环参数之间的统计显着性差异。一项验证性的非配对分析比较了3组：（1）无冠心病的患者的冠状动脉（n = 53），（2）其他冠状动脉之一的狭窄患者的n畅通的冠状动脉（n = 23），以及（3）冠状动脉狭窄（n = 39）。两组之间没有观察到统计学上的显着差异。