背景 主動脈弓手術的主要風險在於出血、腦和脊髓缺氧、心臟衰竭。這些問題導因於傳統的縫線吻合所造成之組織破壞與較長的手術時間。要解決這些問題，非縫線吻合可能是一個有效的解決途徑。在本兩階段的研究中，我們先以手工的單一支架血管來測試非縫線端對端吻合的概念。接著再將此概念延伸至模組化分岔型支架血管系統，並將其運用於廣泛性主動脈弓置換術中，以測試其是否可達成非縫線吻合的目的。
材料與方法 在第一階段的研究中，我們設計一套水力循環系統，以一支直的支架血管來測試其是否可對豬的主動脈進行端對端的非縫線吻合。我們在不同水壓的條件下，先測量支架血管主體本身的基本背景漏水量，再測量吻合後的總漏水量，然後吻合處的漏水量則可根據公式: “吻合處漏水量=總漏水量 – 基本背景漏水量”計算出來。另外也測試使用主動脈外環與否對各種漏水量的影響。在第二階段研究中，我們以一種具有三個分岔的支架血管系統來對八隻豬進行廣泛性主動脈弓置換術的實驗。非縫線吻合被使用在遠處的主動脈弓與其兩條分支動脈上。近端升主動脈部分則以傳統縫線做吻合。在實驗組的六隻豬上，我們在主動脈弓的吻合處加裝外環，而在對照組的二隻豬我們不加外環。在所有的八隻豬中，對於主動脈弓上的兩條分支的吻合處，我們都不加裝外環。
結果 在第一階段實驗中發現，支架血管主體的基本背景漏水量隨著腔內壓力上升而增加(P值為0.000)。同樣的情況亦發生在總漏水量，且不管是否有加裝外環(兩者P值皆為0.000)。然而，當有加裝外環時，吻合處的漏水量並不隨著腔內壓力上升而增加，而是一直維持在接近零附近，此漏水量是遠低於未加裝外環的漏水量(兩者比較的P值為0.001)。在第二階段中，實驗組的六隻豬手術皆成功。在手術時間方面，實驗組的主動脈弓吻合10分鐘內完成，而對照組的則5分鐘內完成。所有豬的主動脈弓分支的吻合可在5分鐘內完成。體外循環的參數中，全身循環終止時間的中位數為30分鐘，主動脈橫夾時間的中位數為67分鐘，體外循環時間的中位數為174分鐘。實驗組的六隻豬皆無吻合處出血的情形，但對照組的兩隻豬都因遠端主動脈弓吻合處出血而死亡。存活豬隻的術後電腦斷層顯示支架排列良好並且與被嵌入的主動脈部位的直徑一致;其組織學檢查顯示所有非縫線吻合部位皆無出現壞死的現象。
結論 本研究證實了以單一支架血管進行非縫線端對端吻合的可行性。此概念被進一步運用到以模組化分岔支架血管系統進行豬隻的廣泛性主動脈弓置換術上。實驗結果顯示此系統可快速有效的做非縫線吻合。其中，主動脈弓部位的吻合必須加裝外環，但主動脈弓分支血管的吻合則不需要外環。

Background. The major risks of aortic arch surgery are bleeding, brain and spinal cord ischemia and heart failure due to tissue destruction and the prolonged procedural time with the conventional suture-based methods. To resolve these problems, sutureless anastomotic method may provide an alternative solution. The aim of this two-staged experimental study was to examine the notion of sutureless anastomosis by using a hand-made single straight stent-graft. Then this notion was extended to a modular branched stent-graft system to test whether it was feasible for sutureless anastomoses in extensive aortic arch replacement in pigs.
Materials and Methods. In the first stage, the feasibility of a single sutureless end-to-end anastomosis using a straight stent-graft was tested in a hydraulic circulation model. The amounts of the leakage from the graft body per se before anastomosis (background reference) and total leakage after sutureless anastomosis were measured under different intraluminal pressures. Then the sutureless anastomotic leakage was calculated from the two values by the formula “Anastomotic leakage = Total water leakage – Background reference”. The influence of external aortic banding on the anastomotic leakage was also examined. In the second stage, the extended aortic arch replacements were performed using the three-branched stent-graft systems in 8 pigs. Sutureless anastomoses were made at the distal arch and the two supra-aortic arteries with the three-branched stent-grafts. The anastomosis at the proximal ascending aorta was performed with the conventional sutures. External banding around the sutureless anastomosis at the distal arch stump was employed in 6 pigs (banding group) and not employed in 2 pigs (control group). No external bands were applied to the two supra-aortic arteries in all pigs.
Results. In the first stage, background reference increased significantly with the increasing intraluminal pressure (P= 0.000). The same results were observed on the total leakage either with or without external banding (both P= 0.000). The anastomotic leakage with external banding was near zero, which was significantly less than that without external banding (P= 0.001). In the second stage, successful procedures were performed on the six pigs of the banding group. The anastomosis at each distal aortic arch was completed in 10 min in the banding group and in 5 min in the control group; the anastomosis of each supra-aortic artery was achieved in 5 min in all pigs. Median durations of the circulatory arrest, aortic cross-clamping, and cardiopulmonary bypass were 30, 67, and 174 min, respectively. No bleeding from all sutureless anastomoses was observed in the six pigs in the banding group. Despite the anastomoses of the two supra-aortic arteries were secure, persistent leakage from the distal arch anastomoses of the two pigs of the control group happened, causing mortality of the two animals. The postoperative computed tomography of the survived pigs in the banding group revealed adequate alignment of the stents and appropriate size-matching between stent-graft and native aorta. The histological examinations revealed no pressure necrosis at all sutureless anastomotic sites.
Conclusions. The present study confirmed the notion of open sutureless end-to-end anastomosis by the single straight stent-graft. This notion was further applied to the three-branched stent-graft system. The results proved the feasibility of applying expeditious sutureless anastomoses in porcine extensive aortic arch replacement. An external banding is essential for the secure hemostasis of the distal arch anastomosis, but it is not required for the supra-aortic arteries.

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