Vu Thang Duc, Oo Min Zin, Nguyen Duc-Viet, Ocampo Ervin Marquez, Ong Yilin, Cheyyatraivendran-Arularasu Suganya, Ti Lian-Kah, Richards Mark A, Kofidis Theo
Department of Surgery, National University of Singapore, Singapore.
Department of Anaesthesia, National University of Singapore, Singapore.
Interact Cardiovasc Thorac Surg. 2018 Jan 1;26(1):131-138. doi: 10.1093/icvts/ivx282.
The transapical approach provides concurrent surgical access to the mitral and the aortic valves, the root of the aorta and the left atrium. We previously showed the feasibility of transapical cardioscopic (TAC) surgery in a non-survival porcine model. However, reproducibility and feasibility of ring implantation using TAC have not been reported. Therefore, in this study, we hypothesized that implantation of a mitral annuloplasty ring can be feasibly and safely carried out endoscopically via the apex of the heart.
Using a porcine model in a short-term survival study, TAC mitral annuloplasty was performed in 6 pigs via an incision over the xyphoid, under cardiopulmonary bypass and cardiac arrest. A mitral annuloplasty ring was implanted via the apex to a normal mitral annulus, using a customized set of instruments and techniques. Haemodynamics, echocardiography, cardiac computed tomography, ventriculography, electrocardiography and histopathology studies were used to evaluate the function of the mitral valve and the left ventricle, coronary system and conduction system in the perioperative period and 4 weeks later.
All 6 animals survived and recovered from the TAC annuloplasty procedure. Postimplantation examination showed that the mitral valve was competent, left ventricular ejection fraction was 63 ± 4%, left ventricular length was 6.2 ± 0.5 cm and left ventricular end-diastolic volume was 80 ± 10 ml, which were comparable to preoperative values. Apart from a dense scar at the apex, no significant injury was noticed on the ventricle, the chordae and the mitral leaflets. The bypass, cross-clamp and implantation times were 181 ± 55 min, 130 ± 37 min and 47 ± 6 min, respectively.
Despite long surgical times due to the initial learning curve, successful execution of mitral ring annuloplasty could be safely achieved using the TAC approach, via a small incision without the involvement of sternum or the right pleural cavity, thereby potentially expanding the indication to patients with high-risk full sternotomy or right thoracotomy.
经心尖入路可同时对二尖瓣、主动脉瓣、主动脉根部及左心房进行手术操作。我们之前在非存活猪模型中展示了经心尖心脏镜手术（TAC）的可行性。然而，使用TAC进行瓣环植入的可重复性和可行性尚未见报道。因此，在本研究中，我们假设经心尖内镜下二尖瓣瓣环成形环植入术能够安全、可行地实施。
在一项短期存活研究中，使用猪模型，对6头猪在体外循环和心脏停搏下经剑突上切口进行TAC二尖瓣瓣环成形术。使用一套定制的器械和技术，经心尖将二尖瓣瓣环成形环植入正常二尖瓣瓣环。利用血流动力学、超声心动图、心脏计算机断层扫描、心室造影、心电图和组织病理学研究，在围手术期及4周后评估二尖瓣及左心室、冠状动脉系统和传导系统的功能。
所有6只动物均存活并从TAC瓣环成形手术中恢复。植入后检查显示二尖瓣功能正常，左心室射血分数为63±4%，左心室长度为6.2±0.5 cm，左心室舒张末期容积为80±10 ml，与术前值相当。除心尖处有致密瘢痕外，未发现心室、腱索和二尖瓣叶有明显损伤。体外循环、主动脉阻断和植入时间分别为181±55分钟、130±37分钟和47±6分钟。
尽管由于初始学习曲线导致手术时间较长，但使用TAC方法经小切口、不涉及胸骨或右胸腔，能够安全地成功实施二尖瓣瓣环成形术，从而有可能将适应症扩大至高风险的全胸骨切开术或右胸切开术患者。
