| BackgroundEnhanced external counterpulsation(EECP) is currently proved to be a safe, effective, noninvasive mechanical adjunctive therapy for coronary heart disease(CHD) by practice, it is also an important supplement of numerous therapeutic measures. Improvement in endothelial function is another important mechanism of EECP, besides improvement in hemadynamics, including promotion of collateralization, enhancement of myocardial perfusion pressure and improvement in cardiac output and so on. Although the research on the mechanism of improvement in endothelial function by EECP is comparative maturity presently, but the report of EECP's effects on arterial stiffness is few , the research on the relationship between endothelial function and arterial stiffness during and after treatment are even less. With the development of new ultrasonographic technology and the widespread cilincal application of some new ultrasonographic indexs, we investigate the effects of long-term EECP on endothelium function and artery stiffness with CHD and explore the relationship of them before and after treatment.Objective1. To observe the change between endothelial function and artery stiffness in patients with coronary heart disease(CHD) treated with enhanced external counterpulsation(EECP), To compare the difference and to analyse the correlation in both of them, and then to explore the mechanism of EECP therapy deeply.2. To study the clinical value of Tei-index for evaluation the heart function of patients with coronary heart disease(CHD) treated by enhanced external counterpulsation(EECP) compared traditional diastolic heart function index .MethodsFirst part: Twenty five subjects with CHD underwent a standard 35-h course of EECP therapy ( 1 hour daily, 5 days one week, over 7 weeks). Some indexs which reflect endothelial function and arterial stiffness were respectively measured before EECP, day 1, day 17, day 35 and one-month follow-up after finished. We respectively measured brachial artery diameter at baseline, endothelial-dependent(flow-mediated dilatation, FMD) and endothelial-independent (nitroglycerin-mediated dilatation, NMD), Then calculated the rate of brachial artery diameter at FMD and NMD compared baseline which reflect endothelial function. Otherwise,some artery stiffness indexs ,such as Ep,βstiffness index and artery compliance(AC) can calculated with systolic diameter and diastolic diameter of carotid artery which measured by ultrasound techniques; In addition, we also can get some popular artery stiffness indexs such as ankle-brachial index(ABI), brachial-ankle pulse wave velocity(BaPWV) and cardio-ankle vascular index(CAVI) by arteriosclerosis monitoring unit.Second part: Twenty five patients with CHD were treated with one course of EECP,left ventricular Tei-index, E/A ratio at mitrial orifice(E/A),isovolumic relaxation time(IVRT),ratio of systolic wave to diastolic wave of pulmonary vein flow(S/D) and atrial reversal wave(ARW) were respectively measured by Doppler Echocardiography before EECP,the first time of EECP instantly,before the second time of EECP,day 17 and day 35.ResultsFirst part:1. EECP decreased SBP and DBP(P<0.05), but SBP decreased more obviously, the blood pressure of one-month follow–up sustained the level of day 35 on the whole. Then EECP decreased PP(P<0.05), the difference of PP at the group comparison had statistical significance between before (or day17) and day35.2. The diameter of brachial artery and NMD% among the treatment of EECP had no significant change(P>0.05). FMD% increased gradually during the treatment, though FMD% had no significant change after the first day treatment, it had statistical significance between before and day 17(before:7.39±2.6% vs day1: 7.62±2.9% ,P>0.05; vs day 17:9.27±3.2%, P<0.05).the comparison between day 35 and all other groups during the treatment had the statistical significance(day 35 :11.36±4.2% vs before: 7.39±2.6%,P<0.01; vs day 1: 7.62±2.9%,P<0.01; vs day 17: 9.27±3.2%,P<0.05; vs one-month follow-up: 7.55±2.2%, P<0.01).In addition, FMD% at one-month follow-up decreased obviously compared with day 17 or day 35, but had no statistical significance compared with before.3. The diameter and IMT of common carotid artery among EECP had no statistical significance(P>0.05). the value of Ep,β,ABI,BaPWV and CAVI gradually decreased at the course of EECP treatment, but the value of AC was opposite. The difference of all group comparisons had statistical significance (P<0.05 or P<0.01). In addition, the difference of these indexs between day35 and one–month follow-up had no statistical significance (P>0.05).4. The indexs such asβ,Ep,BaPWV and CAVI have the negative correlation with FMD% in patients with CHD before EECP(r = -0.710,P<0.001;r = -0.700,P<0.001;r = -0.607,P=0.001 and r = -0.874,P<0.001, respectively), but AC has the positive correlation with FMD% before EECP(r = 0.695,P<0.001). When finished the treatment of EECP, all indexs have no significant correlation with FMD%(β: r = -0.222,P=0.287;Ep: r = -0.376,P=0.064;BaPWV : r = -0.234,P=0.260;CAVI: r = -0.362,P=0.075 and AC: r = 0.255,P=0.219). Second part: The E/A,S/D ratio obviously increased ,while ARW obviously deseased in the first time of EECP instantly compared with before EECP(P<0.01).Then E/A,S/D ratio gradually increased at the last three times measurements compared with before EECP,there has significant differences only between before EECP and day 35 (P<0.01).At the same time ARW gradually deseased and there has significant differences between two groups(P<0.01～0.05).The change of IVRT is same as ARW,but there has no significant differences betweens two groups(P>0.05).Tei-index gradually deseased after therapy,there has significant differences between two groups(P<0.01) except between before EECP and the first time of EECP instantly(P>0.05).Conclusion1. EECP can improve obviously endothelial function and artery stiffness in patients with CHD. but the change of them after EECP was not parallel and it seemed that EECP affected artery stiffness much longer than endothelial function, so arterial stiffness may be another important program to evaluating the long-term clinical therapeutic effects of EECP.2. It is demonstrated that EECP can effectively improved the heart function in patients with CHD ,the Tei-index is a simple and sensitive parameter for evaluation heart allomeric function, and it isn't effected by the preload and afterload of heart.
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