The Study On Full-endoscopic Molecule And Coronary Artery Bypass Grafting

The study on full-endoscopic molecule and coronary artery bypass graftingThe treatment of ischemic heart disease relies mainly on surgical revascularization or angioplasty. Recently, the molecule bypass grafting is on the way. In 1996, an endothelial-specific growth factor known as angiopoietin-l(ANG-l) gene was cloned. ANG-1, which recruits and sustains periendothelial support cells, seems to play a crucial role in mediating reciprocal interactions between the endothelium and surrounding matrix and mesenchyme. It has coordinated and complementary roles in vascular development and play an ongoing role in regulation of vascular permeability. Therefore, to explore the effects of the full endoscopic molecule and coronary artery bypass grafting in ischemic heart disease, we carried out this reseach. The main work is described as follows:1. Construction of the replication-deficient recombinant adenovirus of ANG-1. The target gene encoding human ANG-1 full-length cDNA was cloned byRT-PCR. The ANG-1 cDNA and the PUC119 vector were gigested respectively by Kpn I and BamH I, then were ligated by T4DNA ligase. The ligation mixture was transfected into permeabilized TG1. The recombinant colonies were selected by color and restriction enzyme digestion. The DNA sequence was determined. The ANG-1 cDNA was inserted into El and E3-substituted adenvirus vector PAxCAwt following the cotransfection of 293 host cell line. The right structure and direction of the insert DNA was confirmed by restriction analysis. The replication-deficient adenovirus in which the CMV promotes the transcription of the ANG-1 gene was generated by the method of calcium phosphate coprecipitation from the homologous recombination of the cosmid DNA of ANG-1 and AD5-TPC. All recombinatinant adenviruses were propagated and titrated in 293 cells, purified by cesium chloride density purification, dialyzed, and stored at -70℃. The viral stocks were demonstrated to be free of replication-competent wild type adenoviruses. The virus stocks in high titer were then harvested.2. Full-endoscopic establishment of chronic coronary artery occlusion models The myocardial ischemia was established by gradual occlusion of the leftcircumflex coronary artery (LCx) with an ameroid occluder. Initial surgery was conducted under aseptic conditions and anesthesia (30 mg/kg thiopental) in 20 mongrel canines (10～35kg, either sex). An Ameroid (AM) constrictor was implantedaround the left circumflex coronary artery (LCx) with full endoscopy. Six weeks later, coronary angiography revealed a total occlusion of the LCx arteries. The full-endoscopic surgery is a less invasive way to make coronary artery occlusion animal models.3. Full-endoscopic AD ? ANG-1 injection into ischemic myocardium.Gradual narrowing and occlusion of a coronary artery in patients with atherosclerotic heart disease frequently causes enlargement of the collateral circulation. Although these vessels may protect from development of myocardial infarction, they frequently do not supply sufficient blood flow to prevent ischemia during periods of augmented myocardial oxygen demand. The purpose of this study was to inject AD ? ANG-1 into ischemic myocardium in pigs with totally thoracoscopic instrumention. twenty pigs were instrumented with an Ameroid constrictor around the proximal left circumflex artery. Six weeks after the procedures, in fourteen pigs ,We transferred AD ? ANG-1 into porcin myocardium under the full endoscopy., and the other 6 served as controls. After an average of 6 weeks postoperatively, ECT , electrocardiography(ECG), and HE staining were performed. We found that the nomber of new blood vessels in AD ? ANG-1 group was significantly greater than in control group(P <0.05).Local myocardial structure recovered partly. As a minimally invasive technics, The full-endoscopic procedure may be a novel molecule or cell transplantation approach for the treatment of myocardial ischemia.4. Totally endoscopic coronary artery bypass grafting without the help of robots. The introduction of surgical telemanipulation systems enabled complexintrathoracic maneuvers with the help of robots, and the first totally endoscopic robotic coronary bypass(TECAB) procedure was carried out in 1998. Despite this successful step, only a limited number of TECAB operations have thus far been carried out worldwide. The high cost of the equipment is the main argument against robotic endoscopic CABG. A total of 76 dogs underwent TECAB without the help of robots. The dog was positioned in a 30° left lateral decubitus position, a camera port was introduced into the left third intercostals space on the posterior axillary line. Instrument ports were then inserted through the second and fifth intercostals spaces beside the sternum under thoracoscopic vision. The internal thoracic artery(ITA) was localized and harvested from the first onto the fifth intercostals space. Heparin(1mg/kg) was administed, and after endoscopic placement of a temporarilyoccluding bulldog clamp, preparation of the distal graft portion, as well as free flow check, were carried out. In parallel to these steps, the femoral artery was harvested. After incision of the pericardium, the left anterior descending coronary artery ,the diagonal branches, and the left circumflex coronary artery were identified. Care was taken to see the left anterior descending coronary artery running around the apex of the heart to avoid confusion with diagonal branches. Thereafter, the target vessel was exposed and incised with a lancet knife. The graft was then sutured to the target vessel with a 7-0 running suture. The toe of the anastomosis was sutured first and carried in an out-in manner, and then, the lateral portion and the heel of the anastomosis were carried out in an outside-in manner. The coronary artery anastommtic time is 31.3 ± 4.9 min(20～72min). 32 cases of anastomotic bleeding occurred, and after repair stitches prevented all of the anastomotic bleeding. Because the full-endoscopic technique is less invasive , it might prove to be the technique of choice to perform coronary artery bypass grafting.