PHYSIOLOGIC RESPONSE TO EXTERNAL COUNTERPULSATION (ECP)

点击翻译按钮获取中文摘要

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Extracorporeal counterpulsion (ECP) is a non-invasive and well-accepted method of improving coronary perfusion and improving hemodynamics in patients with severe CAD. It consists of 35 one-hour treatments over seven weeks in which a series of large pneumatic cuffs around the legs and lower abdomen are inflated and deflated during diastole. This improves diastolic perfusion and hemodynamics in a similar fashion to an intra-aortic balloon pump. Although some clinical benefits have been demonstrated, the physiological mechanisms of action of ECP are poorly understood. We hypothesized that the systemic vascular effects of ECP including improved endothelial function, decreased inflammation and improved platelet function are responsible for the clinical benefit observed with ECP. Furthermore, we hypothesize that a secondary effect is improved psychological well-being. The overall goal of this study is elucidate the physiological actions of ECP by measuring changes in vascular properties including endothelial function (via brachial artery reactivity to hyperemia), arterial stiffness (via aortic pulse wave velocity) and peripheral vascular health (via ankle brachial index). In addition we will measure hematologic markers of inflammation, the fibrinolytic state, functional studies of platelet aggregation and molecules of endothelial origin. Electrophysiological remodeling of the heart will be assessed using 24 hour Holter monitoring. Psychological well-being will be measured using the SF-36 questionnaire.