Nichols Wilmer W, Estrada Juan C, Braith Randy W, Owens Karen, Conti C Richard
Department of Medicine/Cardiology, University of Florida College of Medicine, Gainesville, Florida 32610, USA.
J Am Coll Cardiol. 2006 Sep 19;48(6):1208-14. doi: 10.1016/j.jacc.2006.04.094. Epub 2006 Aug 28.
To determine if arterial properties and wave reflection characteristics are favorably altered after enhanced external counterpulsation (EECP) treatment in patients with refractory angina.
Early return of reflected waves from the lower body, resulting from increased arterial stiffness, augments central aortic pressure and increases left ventricular (LV) afterload and myocardial oxygen demand. EECP acutely enhances coronary perfusion (supply) and reduces LV afterload (demand). However, the mechanisms responsible for the sustained beneficial effects of EECP treatment are unclear.
Radial artery pressure waveforms were recorded by applanation tonometry and central aortic pressure waveforms generated using a mathematical transfer function in 20 patients with stable refractory angina. Data were collected before and after 34 1-h EECP sessions. Augmentation index (AI(a)) and timing of the reflected pressure wave were calculated from the aortic waveform.
EECP treatment caused a decline in AI(a) and an increase in reflected wave travel time. These modifications in wave reflection characteristics caused a decrease in aortic systolic pressure and wasted LV pressure energy. The average number of angina episodes and Canadian Cardiovascular Society (CCS) class, both decreased in concordance with the physiologic changes due to EECP treatment.
EECP treatment reduces arterial stiffness and improves wave reflection characteristics in patients with refractory angina. These changes decrease LV afterload and myocardial oxygen demand and reduce the number of angina episodes, therefore enabling patients to participate in continuous exercise programs which in turn may provide long-term benefits and sustained improved quality of life.
确定在难治性心绞痛患者中，增强型体外反搏（EECP）治疗后动脉特性和波反射特征是否得到有利改变。
由于动脉僵硬度增加，来自下半身的反射波提前返回，增加了中心主动脉压，增加了左心室（LV）后负荷和心肌需氧量。EECP可急性增强冠状动脉灌注（供应）并降低LV后负荷（需求）。然而，EECP治疗持续有益效果的机制尚不清楚。
采用压平式眼压计记录20例稳定型难治性心绞痛患者的桡动脉压力波形，并使用数学传递函数生成中心主动脉压力波形。在34次1小时的EECP治疗前后收集数据。根据主动脉波形计算增强指数（AI(a)）和反射压力波的时间。
EECP治疗导致AI(a)下降，反射波传播时间增加。这些波反射特征的改变导致主动脉收缩压下降和LV压力能量浪费。心绞痛发作的平均次数和加拿大心血管学会（CCS）分级均与EECP治疗引起的生理变化一致下降。
EECP治疗可降低难治性心绞痛患者的动脉僵硬度，改善波反射特征。这些变化降低了LV后负荷和心肌需氧量，减少了心绞痛发作次数，从而使患者能够参与持续运动计划，进而可能带来长期益处并持续改善生活质量。
