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Objective To investigate the effect of radiofrequency ablation (RFA) of ventricular outflow tract septum on the left ventricular structure and function in experimental canine.Methods Healthy experimental dogs were used for this study.RFA of the myocardium at ventricular outflow tract septum was performed.Before RFA,thoracic ultrasound examination was used to determine the width of left ventricular outflow tract,the systolic interventricular septum thickness,left ventricular ejection fraction,etc.The ultrasound examination was performed immediately after RFA to check the above indexes.Ultrasound examination was employed one and 3 months after RFA to record the above indexes of the survived dogs,and pathological examination was made.Results Among the 10 experimental dogs,successful RFA was achieved in 9,and one dog died of ventricular fibrillation.In one dog RFA was successfully accomplished,but it died of respiratory inhibition due to over-deep anesthesia.Immediate success rate of surgery was 80％,eight dogs survived to the scheduled follow-up time point.The width of left ventricular outflow tract and the systolic interventricular septum thickness determined immediately after RFA as well as one and three months after RFA in the survived dogs were significantly different from the preoperative data (P＜0.05).Histopathologically,striking microscopic changes could be observed.No obvious changes in ECG and blood pressure were seen.Conclusion The results of this study indicate that RFA of ventricular outflow tract septum in experimental dogs is safe and effective,which provides useful parameters and experimental basis for further animal experiments and clinical trials.
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Objective To discuss the feasibility and effectiveness of transcatheter implantation of double-ring aortic valve stent through puncturing the tip of the heart under thoracotomy.Methods A novel double-ring aortic valve stent was independently designed by the authors.Three healthy goats were selected for this study.A small incision on the left anterolateral thoracic wall was made to expose the cardiac apex,than the puncturing of the left ventricular apex was performed to establish the working pathway.Guided by fluoroscopy,along a hard guide wire a double-ring aortic valve stent was inserted through a 22-French sheath to the site above the aortic valve.By utilizing the opened outer ring of the stent,the double-ring aortic valve stent was accurately placed at the bottom of the aortic valve sinus.Then,the balloon was inflated and the stent was released to substitute the original aortic valve of the experimental goat.The experiment results were evaluated immediately after the procedure.Results Transcatheter aortic valve implantation (TAVI) was successfully accomplished in all the three experimental goats.DSA was performed immediately after the procedure and anatomy evaluation indicated that the position of the implanted artificial aortic valve was satisfactory,which could replace the work of original valve.Conclusion It is technically feasible and clinically effective to use this novel double-ring aortic valve stent to perform TAVI through transapical route by puncturing the left ventricular apex.
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Objective To evaluate the feasibility and safety of a delivery pathway for the performance of percutaneous left atrial appendage (LAA) occlusion in experimental canine models. Methods Transseptal puncture was performed via femoral vein approach under fluoroscopic and angiographic guidance in 12 experimental dogs. A pigtail catheter was advanced into the left atrium (LA), which was followed by LA angiography. The diameters of the neck of LAA were measured on LAA angiogram obtained in appropriate projection. After the delivery sheath was advanced along the wire into LA, a pigtail catheter was inserted into the ostium of the LAA and the sheath was then advanced over the pigtail into the LAA. LAA angiography was then performed through the delivery sheath to confirm the position of the delivery sheath. One hour after the procedure both electrocardiography (ECG) and transthoracic echocardiography (TTE) were carried out in five dogs to check the results, immediately after which the five dogs were sacrificed to macroscopically observe the damages of the puncture site of inter-atrial septum as well as inside the LA and LAA. One hour and 2 weeks after the procedure TTE was conducted in the remaining 7 dogs and these dogs were followed up for one month. Results One dog died of pericardial tamponade during the operation. In 8 dogs the LAA was clearly displayed in the projection position of right anterior oblique (RAO) 30°/cranial (CRA) 20°,while in 3 dogs the LAA was well visualized in the projection position of RAO 30° , and in one dog in the projection position of RAO 30°/caudal (CAU) 20°. The diameter of LAA neck was (13.6 ± 5.2) mm. The delivery sheath was safely advanced into the LAA along the pigtail catheter in all dogs, and no air embolism, thrombus or pericardial tamponade occurred. Hematoma at puncture point of groin occurred in 2 dogs, which was absorbed through pressure dressing. Macroscopic examination of the heart performed immediately after the operation showed that no bloody pericardial effusion was found, and mild hematoma at posterior wall of LA was seen in one dog and mild damage of the upper-margin intima of LAA was noted in 2 dogs. The mean fluoroscopy time was (10.1 ± 2.5) minutes and the mean operation time was (58 ± 12) minutes. TEE showed no pericardial effusion 2 weeks after the procedure. During the follow-up period of one month no sudden death, stroke or infection occurred. Conclusion This method of placing the delivery sheath into the LAA is clinically safe and effective, and it can reliably establish a pathway to advance the LAA occluder into LAA.
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<p><b>OBJECTIVE</b>To evaluate the feasibility and effectiveness of transcatheter aortic valve implantation assisted with snare to fix the delivery system.</p><p><b>METHODS</b>This study was made in 5 healthy goats. After the abdomen was opened and the abdominal aorta was exposed, a stiff guide wire was advanced into the apex of the left ventricle through abdominal arterial puncture points. The delivery catheter equipped with valved stent was inserted into the descending aorta under fluoroscopy along the stiff guide wire. A minimal thoracic surgery approach was used to access the apex of the heart. A J-type guidewire and 5 F multifunction catheter were placed transapically and across the aortic valve down to the descending aorta. The snare was introduced through the 5 F catheter into the ascending aorta and was controlled to seize the head of stent delivery catheter. Then the delivery catheter was advanced into the left ventricle. The valved stent was positioned in the desired position under aortography and then the balloon was dilated and the valved stent was deployed into the aortic annulus assisted with snare to fix the catheter to prevent stent dispositions. Aortic angiography and echocardiography were performed to evaluate of valve performance post procedure.</p><p><b>RESULTS</b>The interventional procedure was completed successfully in all 5 goats. The mean aortic annulus diameter was (23.8 ± 2.6) mm, two valved stent of 23 mm diameter and three valved stent of 26 mm in diameter were implanted. The operation duration and X-ray exposure time were (112.3 ± 19.5) min and (16.8 ± 5.2) min, respectively. Immediate observation after procedure showed that the valved stents were in the desired position after implantation by angiography and echocardiography. No moderate to severe aortic regurgitation was observed. All goats were alive at 1 month post procedure.</p><p><b>CONCLUSIONS</b>The procedure of transcatheter implantation of a balloon-expandable valved stent into the aortic valve position of goats assisted with snare to fix the delivery catheter is feasible and effective. This procedure might be suitable also for patients with noncalcified aortic stenosis.</p>
Subject(s)
Animals , Aorta , Aortic Valve , Aortic Valve Insufficiency , Catheterization , Echocardiography , Fluoroscopy , Goats , Stents , Transcatheter Aortic Valve ReplacementABSTRACT
Human beta defensin 2 (HBD-2) may play an important role in human defense against infection. Its antimicrobial capacity has been fully documented in in vitro study. In order to evaluae its in vivo effects, we developed an HBD-2 transgenic mouse model. The HBD-2 minigene containing CMV promoter, full length of HBD-2 cDNA and BGH polyA tail was generated by PCR amplification and introduced into the fertilized oocytes of C57 X ICR hybridized mouse by microinjection, and offspring were produced. DNA was isolated from the tails of the mouse pups, and the HBD-2 minigene incorporation was analyzed by PCR using HBD-2 specific primers. The HBD-2 gene expression in the multi-tissues of transgenic mice was determined at mRNA level by RT-PCR and at peptide level by immunohistological staining with the use of HBD-2 monoclonal antibody. The results showed that among 17 F0 transgenic mice, HBD-2 positive signal was determined by PCR in 4 mice, suggesting that HBD-2 minigene has been incorporated into the offspring mice. Meanwhile, a widespread expression of HBD-2 mRNA and peptide was detected in the F1 transgenic mice's multi-tissues such as trachea, lung, intestine, esophagus, testis, spleen, skin, endothelium and brain.