Microvascular Damage During Myocardial Ischemia-reperfusion: Pathophysiology, Clinical Implications and Potential Therapeutic Approach Evaluated by Myocardial Contrast Echocardiography

During myocardial ischemia produced by coronary occlusion, coronary microvessels and cardiac myocytes undergo progressive functional and structural changes. The prompt reopening of the epicardial vessel is the main therapeutic strategy to limit the vascular and cellular damage. However, the full benefit of reperfusion can be limited by progressive microvascular obstruction and cell death occurring after the reestablishment of flow. During ischemia-reperfusion, preservation of the integrity of the coronary microvasculature is a fundamental prerequisite to ensuring myocardial viability. Therefore, therapeutic approaches should be developed to prevent and treat microvascular impairment resulting from ischemia-reperfusion. Also, given the importance of the assessment and treatment of post-reperfusion disorders of coronary microvasculature, a diagnostic tool able to evaluate the structural and functional status of the microcirculation in vivo is needed. Myocardial contrast echocardiography has been demonstrated to be extremely useful in this setting. In this review, the anatomic and functional characteristics of the coronary microcirculation are described during normal conditions, as well as in the presence of ischemia-reperfusion injury. The role of myocardial contrast echocardiography in the assessment of microvascular dysfunction and specific potential therapeutic approaches to the treatment of microvascular damage during ischemia and after reperfusion are also discussed.