大動脈基部置換術における右冠状動脈再建

Precautions for Coronary Artery Reconstruction in Aortic Root Replacement

大動脈基部置換術はBentall手術が標準術式であり，また大動脈弁尖の性状が比較的保たれている若年例に対しては，自己弁温存基部置換術はよい予後が期待できる術式となっている．しかし，基部置換術の予後不良因子として当初から周術期心筋梗塞があげられており，冠状動脈再建が予後を左右する重要な手技であることは論を俟たない．

Aortic root replacement is based on the Bentall procedure, and if appropriate cases are selected, valve-sparing surgery has good results. However, peri-operative myocardial infarction has been reported as a serious morbidity, and coronary artery reconstruction must be performed preventing this complication. Our results also indicate that prevention of kinking of the right coronary artery was associated with an improved prognosis. We believe that the enlarged sinus of Valsalva was replaced by a composite graft, the ostium of the right coronary artery was consequently located distance away from the graft. By reconstructing the right coronary artery in a left posterior and cephalic position, i.e., by traction toward the left shoulder, we can compensate for this misalignment and prevent kinking. Bentall procedure with a prosthetic composite graft has been a gold standard procedure as an aortic root replacement. When appropriate cases are selected, valve-sparing surgery can yield better results. However, peri-operative myocardial infarction has been reported as a serious morbidity. In addition, our present clinical analysis revealed that prevention of kinking of the right coronary artery is associated with an improved long-term prognosis. The technical aspects of coronary artery reconstruction are therefore of paramount importance. In particular, the more likely the right coronary artery is to be misaligned and kinked. The larger the sinus of Valsalva, the more likely the right coronary artery is to be misaligned and kinked. After excision of the enlarged sinus of Valsalva and replacement with an adequate size of prosthetic composite graft, the optimal position for the reattached right coronary button should be altered from the preoperatively deviated position due to the aneurysmal sinus of Valsalva. We believe that reconstructing the right coronary artery in a cephalad position and in a slightly counterclockwise direction by rotating the tip of the right coronary button towards the left shoulder may compensate for potential misalignment and help prevent kinking of the critical branch.