Institute for Surgical Research, Walter Brendel Center of Experimental Medicine (WBex), University Clinic, LMU Munich, Munich, Germany.
German Center for Cardiovascular Research (DZHK), Munich Heart Alliance (MHA), Munich, Germany.
Am J Physiol Heart Circ Physiol. 2021 Jun 1;320(6):H2351-H2370. doi: 10.1152/ajpheart.00992.2020. Epub 2021 May 7.
Until recently, epicardial coronary stenosis has been considered the primary outcome of coronary heart disease, and clinical interventions have been dedicated primarily to the identification and removal of flow-limiting stenoses. However, a growing body of literature indicates that both epicardial stenosis and microvascular dysfunction contribute to damaging myocardial ischemia. In this review, we discuss the coexistence of macro- and microvascular disease, and how the structure and function of the distal microcirculation is impacted by the hemodynamic consequences of an epicardial, flow-limiting stenosis. Mechanisms of endothelial dysfunction as well as alterations of smooth muscle function in the coronary microcirculation distal to stenosis are discussed. Risk factors including diabetes, metabolic syndrome, and aging exacerbate microvascular dysfunction in the myocardium distal to a stenosis, and our current understanding of the role of these factors in limiting collateralization and angiogenesis of the ischemic myocardium is presented. Importantly, exercise training has been shown to promote collateral growth and improve microvascular function distal to stenosis; thus, the current literature reporting the mechanisms that underlie the beneficial effects of exercise training in the microcirculation distal to epicardial stenosis is reviewed. We also discuss recent studies of therapeutic interventions designed to improve microvascular function and stimulate angiogenesis in clinically relevant animal models of epicardial stenosis and microvascular disease. Finally, microvascular adaptation to removal of epicardial stenosis is considered.
直到最近,心外膜冠状狭窄才被认为是冠心病的主要结果,临床干预主要致力于识别和消除限制血流的狭窄。然而,越来越多的文献表明,心外膜狭窄和微血管功能障碍都导致心肌缺血损伤。在这篇综述中,我们讨论了大血管和微血管疾病的共存,以及心外膜、血流受限狭窄的血流动力学后果如何影响远端微循环的结构和功能。我们讨论了内皮功能障碍的机制以及狭窄远端冠状动脉微循环中平滑肌功能的改变。包括糖尿病、代谢综合征和衰老在内的危险因素会加重狭窄远端心肌的微血管功能障碍,我们目前对这些因素在限制缺血心肌侧支循环和血管生成中的作用的理解也在本文中呈现。重要的是,运动训练已被证明可促进侧支生长并改善狭窄远端的微血管功能;因此,本文还回顾了目前关于运动训练在心外膜狭窄远端微循环中有益作用的机制的研究。我们还讨论了最近的一些研究,这些研究旨在改善心外膜狭窄和微血管疾病的临床相关动物模型中的微血管功能和刺激血管生成。最后,还考虑了心外膜狭窄消除后的微血管适应。