Downstream Influence of Coronary Stenoses on Microcirculatory Remodeling: A Histopathology Study

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