Objective To investigate and evaluate the safety and effectiveness of the Chimney technique in mitral valve reoperation. Methods The clinical data of mitral valve reoperation patients who underwent Chimney surgery in Wuhan Asia Heart Hospital from 2019 to 2021 were retrospectively analyzed. Results A total of 26 patients were collected, including 7 males and 19 females, aged 27-67 (53.46±11.18) years. All patients had previous mitral valve surgery, including 23 mitral valve replacements and 3 mitral valve repairs. All patients received Chimney technique using the ideal artificial sized mitral valve, and 1 patient died of neurological complications in hospital. The cardiopulmonary bypass time and the aortic cross-clamping time were 231.11±77.05 min and 148.50±52.70 min, respectively. The mean diameter of the implanted mitral valve prosthesis was 29.08±0.68 mm, which was statistically different from pre-replacement valve prosthesis size of 26.69±0.77 mm (P＜0.001). The mean transvalvular pressure gradient of the prosthetic mitral valve measured on postoperative echocardiography was 14.77±5.34 mm Hg, which was statistically different from preoperative value of 20.92±9.83 mm Hg (P=0.005). Conclusion The Chimney technique is safe and effective for reoperation in patients with small mitral annuli, which can not only reduce the risk of reoperation, but also obtain larger prosthetic valve implants with good hemodynamic characteristics and clinical outcomes.
Objective To investigate and evaluate the safety and efficacy of the aortic-mitral annular enlargement technique (double annular enlargement) in patients with small-size valve prostheses after prior valve surgery. MethodsThe clinical data of patients who underwent double valve annular enlargement in Wuhan Asia Heart Hospital from April 2020 to April 2022 were retrospectively analyzed. Results A total of 30 patients were collected, including 2 males and 28 females aged 9-78 (52.71±3.53) years. All patients had previous heart valve surgery, including 1 patient receiving the third heart surgery. All patients were operated on successfully and there were no postoperative in-hospital deaths. There was no postoperative bleeding which needed a secondary open-chest hemostasis, and one patient underwent permanent pacemaker implantation due to postoperative sick sinus syndrome. The mean diameter of the implanted prosthetic aortic valve was 24.23±1.60 mm, which was significantly larger than that of the preoperative aortic valve (21.03±1.90 mm, P＜0.001). The mean diameter of the implanted prosthetic mitral valve was 28.33±1.21 mm, which was significantly larger than that of the preoperative mitral valve (25.43±0.84 mm, P＜0.001). The mean peak gradient difference across the prosthetic aortic valve on postoperative echocardiography was 18.17±6.44 mm Hg, which was significantly lower than that of the preoperative aortic valve (82.57±24.48 mm Hg, P＜0.001). The mean peak gradient difference of the postoperative prosthetic mitral valve was 12.73±5.45 mm Hg, which was significantly lower than that of the preoperative mitral valve (19.43±8.97 mm Hg, P=0.003). Conclusion The double annular enlargement technique is safe and effective for reoperation in patients with a history of valve surgery with a small aortic root to obtain both a larger size prosthetic valve for a larger orifice area and stability of the mitral-aortic valve union, resulting in good postoperative hemodynamic characteristics and clinical outcomes.
ObjectiveTo establish a model of tracheomalacia in beagle dogs.MethodsSix healthy male beagles were selected with a weight of 12-15 kg and age of 12-18 months. The dog was placed in supine position after being anesthetized. Then midline incision was performed on dogs' cervical skin and main trachea was dissected. Six continuous cartilage rings separated from the tracheal wall were removed. Finally, the endotracheal mucosal was examined and the wound was sutured layer by layer. Different degrees of cartilage were removed to simulate different degrees of tracheomalacia. The beagle dogs were classified into two groups (n=3 in each group): a mild tracheomalacia (MTM) group (part of the cartilage near the trachea membrane was retained) and a severe tracheomalacia (STM) group (cartilage was removed as much as possible).ResultsThe dogs in the MTM group survived for a long time after the operation, showing symptoms of airway stenosis such as wheezing and coughing. The dogs were killed at postoperative week 2, and the pathological examination was performed. In the STM group, severe asphyxia occurred in the experimental animals after tracheal intubation removed, and all dogs died within 1 hour after surgery. Postoperative bronchoscopy revealed that the trachea of the MTM group dogs collapsed in the phase of inhalation, but it could maintain a certain patency. The trachea of the STM group dogs collapsed completely in the phase of inhalation. Postoperative X-ray showed that the diameter of the airway in the MTM group was reduced and trachea did not completely collapse. In the STM group, the trachea collapsed completely at the cartilage removed segment. Pathological examination showed that the cartilage in the MTM group was partially removed and tracheomalacia was obvious in the cartilage removed segment. In the STM group, most of the cartilage was removed with only few cartilages left.ConclusionThe clinical symptoms of tracheomalacia in different degrees can be simulated and repeatable. Animal models can be established by controlling the degree of removal of tracheal cartilage ring in dogs. This method provides a simple, repeatable and standardized large animal model for the treatment and transformation of tracheomalacia.