Cardiovascular Surgery Unit, Cardiocentro Ticino, Lugano, Switzerland.
Cardiovascular Surgery Unit, University Hospital of Zurich, Zurich, Switzerland.
Interact Cardiovasc Thorac Surg. 2020 Jul 1;31(1):121-128. doi: 10.1093/icvts/ivaa056.
Transcatheter aortic root repair is still not available because of the technical challenge of coronary perfusion. The use of chimney grafts for coronary ostia can be an option and we tested the flow-through coronary chimney grafts deployed in a 3-dimensional-printed root model as part of a transcatheter aortic root repair system.
A 3-dimensional-printed root was used to test the coronary flow after the deployment of 1 root endograft (28 mm diameter) and two 6-mm diameter 10-cm long coronary chimney grafts. Continuous coronary flows were measured in a bench test at different pressure levels (60, 80 and 100 mmHg) and compared to target coronary flows (250 ml/min at rest for the left and 150 ml/min at rest for the right coronary artery).
The computed tomography scan-based root was modified with two 5-mm diameter coronary conduits to overcome the limits of the original 3-dimensional-printed coronary ostia. The root was placed in the hydrodynamic system: adjusted coronary free flow at 60, 80 and 100 mmHg of pressure was 1913, 2200 and 2480 ml/min for left coronary and 1633, 2026 and 2366 ml/min for right coronary, respectively. After endografts deployment, mean chimney graft flow at 60, 80 and 100 mmHg of pressure was 1053 ml/min (-45%), 1306 ml/min (-41%) and 1502 ml/min (-40%) for the left coronary and 1100 ml/min (-33%), 1460 ml/min (-28%) and 1626 ml/min (-31%) for the right coronary, respectively.
In this preliminary study, chimney grafts for transcatheter aortic root repair provided 830% of target flow in the right coronary (-31% of free flow) and 414% of target flow in the left coronary (-42% of free flow) which is more than sufficient for both coronaries in real-life conditions. The potential of this approach should be further explored with specifically designed endografts.
由于冠状动脉灌注的技术挑战，经导管主动脉根部修复仍然不可行。使用烟囱移植物进行冠状动脉口可以是一种选择，我们测试了在经导管主动脉根部修复系统中部署的 3D 打印根部模型中的流通式冠状动脉烟囱移植物。
使用 3D 打印的根部来测试在部署 1 个根部内移植物（直径 28mm）和 2 个 6mm 直径 10cm 长的冠状动脉烟囱移植物后的冠状动脉流量。在不同压力水平（60、80 和 100mmHg）下进行台架测试以测量连续冠状动脉流量，并与目标冠状动脉流量（左冠状动脉休息时为 250ml/min，右冠状动脉休息时为 150ml/min）进行比较。
基于 CT 扫描的根部经过修改，增加了两个 5mm 直径的冠状动脉导管，以克服原始 3D 打印冠状动脉口的限制。根部被放置在水动力系统中：在 60、80 和 100mmHg 的压力下，左冠状动脉的冠状动脉自由流量分别调整为 1913、2200 和 2480ml/min，右冠状动脉分别调整为 1633、2026 和 2366ml/min。在部署内移植物后，在 60、80 和 100mmHg 的压力下，平均烟囱移植物流量分别为左冠状动脉 1053ml/min（-45%）、1306ml/min（-41%）和 1502ml/min（-40%），右冠状动脉 1100ml/min（-33%）、1460ml/min（-28%）和 1626ml/min（-31%）。
在这项初步研究中，用于经导管主动脉根部修复的烟囱移植物在右冠状动脉中提供了目标流量的 830%（自由流量的-31%），在左冠状动脉中提供了目标流量的 414%（自由流量的-42%），这对于真实条件下的两条冠状动脉来说已经足够了。应该进一步探索这种方法的潜力，特别是使用专门设计的内移植物。
