| Background and Objective:The endothelium is a thin monolayer with flattened and orthogonal cells that covers all inner surface of the blood vessels. As a direct interface between the components of circulating blood and local vascular smooth muscle, the endothelium is not only a mechanical barrier, but also a regulator with various important functions of the vasculature. The clinical relevance of endothelial dysfunction to many disease, especially cardiovascular disease, is strongly supported by many studies showing that abnormalities of the vascular endothelium function not only contribute to the initiation of atherosclerosis and coronary artery disease(CAD), but also play a critical role in the formation, progression, and rupture of atherosclerotic lesions. Given the links between endothelial dysfunction and atherosclerosis, it is not surprising that many clinical subtypes of CAD, such as angina pectoris and acute myocardial infarction, have diffused endothelial dysfunction.Because of the central role of the endothelium in the development and clinical course of atherosclerosis, test of endothelial function may have a significant clinical value for coronary artery disease. ET-1 and vWF are vasoactive substances which are released from the vascular endothelial cells. sP-selectin is a plasma marker of platelet activation and endothelial dysfunction/damage. Soluble isoforms of these molecules shed from the surface of activated cells can now be quantitated in peripheral blood,suggesting that they could be reliable markers of endothelial function.Disturbed endothelial function and abnormal left ventricular diastolic function coexist in patients with CAD under most circumstances.Indeed, myocardial ischemia may manifest early as diastolic function was impaired. Doppler tissue imaging, by measuring velocities at the mitral annulus, is a novel and noninvasive technique allowing real-time quantitative analysis of regional myocardial motion,which is a more sensitive and specific indicator of left ventricular relaxation than conventional echocardiograph. Serum ET-1,vWF,sP-selectin were checked in this study, pulsed Doppler mitral valve flow pattern and mitral annular velocity detected by tissue Doppler imaging were used to assess left ventricular diastolic function in CAD patients for the purpose of evaluating endothelial function of CAD patients in different types and revealing the inner relationship between left ventricular diastolic function and endothelium dysfunction in order to find out high-risk group and direct treatment.Methods:A total of sixty-four patients admitted with coronary heart disease from February to June in 2006 were studied. Patients were classified into 3 groups. Group I included 51 patients with ACS among which there were 20 patients with AMI and 31 patients with UA.Group II included 13 patients with SA. Group III included 22 cases of age matched control individuals. Serum ET-1, vWF and sP-selectin were determined quantitatively by enzyme linked immunosorbent assay(ELISA) method and echocardiography was performed. Initially, a conventional echocardiographic examination was performed. Early (E) and atrial (A) transmitral peak flow velocities , the E/A ratio were measured and LVEF was estimated. Then,the system was switch to TDI velocity mode. Apical four- and two-chamber views were obtained to display the movement of the 4 left ventricular walls (septum and lateral wall, and anterior and inferior wall, respectively).The mean of peak early diastolic velocities(Em), peak late diastolic velocity(Am) were recorded. The ratio of Em/ Am and E/ Em were calculated. All of these data were compared among all groups statistically.Results:1 Serum level of ET-1, vWF and sP-selectin in patients with ACS were remarkably higher than those with SA and control group, there were significant difference between ACS group and SA group and control group(P<0.05).There was significant difference in serum level of ET-1 between SA and control group(P<0.05), but no significant difference in serum level of vWF and sP-selectin between the two groups (P>0.05). Serum level of ET-1, vWF and sP-selectin in AMI group were remarkably higher than that in UA group, and there was significant difference (P<0.05).2 Compared with controls, LVEF and E/A which represent systolic function and diastolic function respectively were lower, but there was no significant difference (P>0.05). Peak early diastolic velocities(Em) , the ratio of peak early diastolic velocity ( Em) over late diastolic velocity(Am) were lower while E/Em, Am were higher in CAD patients. There was significant difference in Em, Em/ Am and E/ Em between CAD patients and control group(P<0.05),but no significant difference in Am between the two groups (P>0.05).3 There was a correlation between sP-selectin and vWF, ET-1 and vWF in CAD patients (r= 0.532, 0.498, respectively. P<0.05). ET-1, vWF, sP-selectin levels correlated negatively with the Em assesses by DTI (r= - 0. 52, - 0. 45 , - 0.52, respectively. P<0.05) in CAD patients. Em/Am correlated negatively with ET-1 (r= - 0.57, P<0.05), however, no correlation existed between Em/Am and vWF, Em/Am and sP-selectin (r= - 0.20, - 0.10, respectively. P>0.05).Conclusions:1 ET-1, vWF and sP-selectin can be regarded as the index of endothelial damage/ dysfunction, the serum level of which represent severity of the illnesss. 2 Diastolic function may be a more sensitive marker of ischaemic injury. Even the systolic LV function is preseved or normal, there still is impaired LV diastolic function in CAD patients. Doppler tissue imaging, by measuring peak velocities during early diastole (Em) and late diastole (Am), expecially the Em, is more sensitive and specific in the assessment of a favorable LV diastolic function in patients with CAD than mitral inflow parameters recorded by conventional echocardiograph.3 Endothelial damage/dysfunction in patients with CAD is closely associated with LV diastolic dysfunction. Diastolic dysfunction and endothelial damage interact with each other and together promote the formation, progression of atherosclerotic lesions. |
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