COMPARATIVE EXPERIMENTAL STUDY OF HO-YAG LASER AND TRUE- CUT BIOPSY NEEDLE IN MYOCARDIAL REVASCULARIZATION

Objective.To study the mechanism and effects of blood perfusion on acute ischemic region of myocardium through channel created by Ho- Yag laser and True- cut biopsy needles with myocardial contrast echocardiography. Methods. We partially ligated the left anterior descending coronary artery of canine hearts between the lst and 2nd diagonal branches to produce two groups of acute myocardial ischemia models and then performed tran- smyocardial revascularization (TMR) on this region with Ho- Yag laser and True- cut biopsy needles. Myocardial contrast echocardiography was performed with a new generation of ultrasound contrast agent and second harmonic imaging of this region before, during ischemia and after revascularization. Pictures were taken with“ R” wave trigger skill. Results. Acoustic density (dB) in the ischemic region (anterior wall) with myocardial contrast echocardiography decreased obviously after the left anterior descending artery was ligated (Laser group: 5.40± 1.81, Needle group: 7.11± 2.51) compared with that before (Laser group: 11.69± 1.61, Needle group: 12.96± 2.88, P< 0.01). dB increased remarkably after TMR by either laser or True cut biopsy needle (Laser group: 11.02± 2.01, Needle group: 10.01± 4.45. P< 0.01) compared to that during ischemia and approximated to that before ischemia (P >0.05). We found that the acoustic density of the contrast developed one picture (one cardiac cycle) ahead in the transmyocardial revascularization region than that in the lateral and other region of the left ventricle wall in the scan of both groups. Conclusions. Acute ischemic myocardium can be perfused immediately by oxygenated blood from the left ventricle through channels created with both Ho- Yag laser and True- cut biopsy needles. Evidence of blood perfusion through these channels mainly during systolic phase was detected, and myocardial contrast ultrasound using intravenous perfluorocarbon- exposed sonicated dextrose albumin was regarded as a reliable method in the study of transmyocardial revascularization.