Research On The Anatomic Basis And The Clinical Application Of Selective Retrograde Coronary Venous Bypass

Coronary artery bypass grafting ( CABG) was accepted widely, but some problems still need to be solved. One of those problems is that CABG could not be performed in patients with disseminated changes and distal occlusion of coronary artery, accounting for 12 15 or even more percentage of patients waiting for the operation. With regard to the problem ,the patients may benefit from the researches of selective retrograde coronary venous bypass ( SRCVB) . In this study , the emphases were placed on the aspect of the myocardial perfusion and the clinical effects of SRCVB .Object1. To find anatomic evidence that myocardium can be supplied through SRCVB and then to show the feasibility of SRCVB.2. To evaluating the clinical effects ,analising the clinical pre - and post -operation data of patients receiving SRCVB and comparing the levels of Tropnin and myocardial enzymes in early period after operation between OPCAB and SRCVB group.Method1. Basic experimentsFive fresh complete ex vivo porcine hears were washed in 25℃ 0.9% natri chloridi and the thrombi in the chambers of heart were removed. Cut up coronary venous sinus in the right atrium and inserted the soft silica gel pipe (diameter =2mm) into middle cardiac vein ( MCV) about 2.0 2.5cm. Ligated MCV at the point 1.0 1. 5cm away from the front end of the pipe 1-2 circles , in the same time , and transfixed posterior descending artery (PDA) . 20ml of Heparin saline (500ml physiologic saline plus 300mg low molecular heparin) rinsed the MCV and its attributive branches , and then 500 ml ink (Tianjing ostrich ink limited company) contained in plastic bottle packaged up by aerated presser were utilized to perfuse the myocardium through MCV . There was a pressure transducer , which connected with a monitor , between the infuser and the inserted silica gel pipe . Regulating the height of the plastic bottle and the pressure of the a-erated presser , and adjust the pressure displayed on the monitor within 40 80mmhg . 80 100ml ink was perfused into each porcine heart and then put them into 10% formalin . After paraffin imbedding , making slides of 5μm thick along the long axis of heart and observing through the microscope .2. Clinical researches2.1 The research objects were the ones who had received SRCVB , and the pre — and post — operation clinical data included : 1) the grade of angina pectoris ;2) the changes of ST segment on ECG;3) the indexes of ultrasound car-diography ( UCG) ( E, A, E/A and EF value and the scores of the segmental movements of the SRCVB - related ventricle) ;4) the results of single photon e-mission computed tomography ( SPECT) ( LVEV, EDV, ESV and SV and the scores of the segmental perfusion of the SRCVB - related ventricle ). Using the index of rate to analyze the dichotomous data and making the statistical comparison by x² Test . Making the comparison between the measurement data of two groups by paired T Test . There was statistical significance when P value was lesser than 0.05 .2. 2 Comparing the levels of troponin and myocardial enzymes in early period after operation between CABG and SRCVB group and doing the test of homogeneity of variance between two groups before the T Test of the means . There was statistical significance when P value was lesser than 0.05 .1. The ink retrograde perfused from MCV distributed in intercellular spaces and capillaries of the myocardium , and appeared in micro - arteries . In the other word , the ink could flow from MCV to the related micro - arteries .2. 1 From 2002 to 2004 ,16 patients underwent SRCVB with different degrees of the elevation and depression of ST segments on preoperative resting ECG ; subsequently , the ST segments of 15 patients recovered to the baseline on postoperative resting ECG except one patient with the depression of the ST segment on V₃ lead (who had the depression of the ST segment on V3 to V5lead before surgery ) and so the recovery rate of the ST segment was 93.15 % . The postoperative improvement rate of the class of angina pectoris was 100 % , and the class of 2 patients switched from class HI to class I and the class of 14 patients from class IV to class II. The results of SPECT showed that there was statistical significance between pre - and post - operative data of LVEF , EDV and ESV , but no significance of SV ; and the improvement rate of the radioactive distribution of nuclide was 100 % , among which the significant improvement rate and partial improvement rate were both 50 % (8/16). The results of UCG indicated that there was no significance of the data of LVEF , E and A between SRCVB and CABG group 10 days after operation , but statistical significance 3 months after operation . The scores of segmental movements of left ventricles showed that the improvement rates of SRCVB - related myocardium 10 days and 3 months after operation were 50 % (8/16) and 87. 5 % (14/16) respectively . There was statistical significance when comparing between the rates of SRCVB and CABG group( P <0.05). .2. 2 Comparing the levels of troponin and myocardial enzymes in early period after operation between CABG and SRCVB group, P >0. 05 and there was no statistical significance.