Abstract
Aiming for improved long-term post-surgical outcomes, we adopted a simplified and safe descending aorta stent graft implant procedure (modified open stent graft technique; MOS) for use during circulatory arrest in hemi-arch replacement (HAR) and evaluated its effectiveness. We analyzed 76 consecutive HAR procedures conducted for acute type A dissection at our institution from April 2007 to March 2011. The C group consisted of 16 HAR cases conducted with the normal technique, and the S group consisting of 60 cases treated by HAR+MOS. In 36 cases used home-made stent grafts and the TALENT thoracic stent graft in 24 cases. The stent grafts were prepared for insertion using a braiding technique and were introduced through the opened proximal descending aorta and deployed under circulatory arrest. For evaluation, we used early and mid-term CT analysis, and analyzed the status of closure of the false lumen, as well as the diameter of the true and false lumens in the descending thoracic aorta and the abdominal aorta. There was no significant difference in patient backgrounds, in surgical time, aortic cross-clamp time, or lower body ischemic time. There were two surgery-related deaths in the C group (one case of left ventricular rupture, and one case of descending aortic rupture), and one in the S group (intestinal necrosis). There were no cases resulting in paraplegia or malperfusion. Early post-operative CT imaging was conducted on 14 cases in the C group (88%) and 53 cases in the S group (88%). Complete thrombosis of the false lumen in the descending aorta in the C group was found in 6 cases (43%), and in 31 cases (58%) in the S group. There were 7 cases (50%) in the C group which were true lumen dominant, compared with 44 cases (83%) in the S group, with the S group being significantly higher. Mid-term CT imaging was conducted on 12 cases (86%) in the C group, and on 30 cases (51%) of the S group. The false lumen in the descending aorta had shrunk or disappeared in 3 cases (25%) of the C group and in 15 cases (50%) of the S group. The proportion of cases in the descending aorta that had an increase in diameter in the C group was 6 cases (50%) and 4 cases (13%) in the S group, with the S group being significantly smaller, and the C group requiring one re-do surgery. MOS requires less than 3 minutes of stent graft implant time, has few peri-surgical or post-surgical complications, and can be conducted safely. Mid-term post-surgical shrinkage of the false lumen in the descending aorta, as well as the high closure rate for the S group compared with the C group, allows us to expect a decreased risk of re-do surgery and danger of rupture due to an increase in the size of the false lumen in the long-term.
