Aortic Remodeling Following Sun's Procedure for Acute Type A Aortic Dissection

Background: Sun's procedure is a surgical technique widely used in type A aortic dissection. The purpose of this study was to analyze clinical outcomes and morphologic changes in true and false lumen by computed tomography (CT) angiography after Sun's procedure. Material/Methods: We retrospectively reviewed 51 patients who underwent Sun's procedure for acute Stanford type A aortic dissection extending down to iliac bifurcation between January 2013 and December 2014. The images of pre-operative, one-month, three-month, and six-month follow-up were analyzed by CT angiography to measure the area and diameter of true and false lumen. Results: Four patients died before surgical intervention and postoperative deaths occurred in five patients (in-hospital mortality rate 10.6%). Only 42 patients (36 male, 6 female; mean age, 45.9 +/- 9.8 years; range, 24-65 years) with acute type A aortic dissection were involved in our study. Thirty-five patients (83.3%) suffered from chest or abdominal pain and only one patient (2.4%) was asymptomatic. Thirty-seven patients (88.1%) had hypertension as the most common comorbidity. In the ascending aorta, false lumen was eliminated and the change of true lumen was not significant (p>0.05). In the descending aorta, complete and partial thrombosis of false lumen were observed in eight patients (19.0%) and 33 patients (78.6%) by one-month follow-up CT scan, respectively. After the six-month follow-up, the rate of complete thrombosis increased to 36.1% and partial thrombosis decreased to 61.9%. The area and maximal diameter of true lumen were increased significantly (p<0.05), whereas significant decreases were found in the area and maximal diameter of false lumen (p<0.05). In the abdominal aorta, thrombosis was found in 52.4% patients at one-month follow-up CT. Furthermore, there were no significant changes in both true and false lumen within three months (p>0.05). Nevertheless, the false luminal area and maximal diameter decreased significantly (p<0.05) after six months, while these changes of true lumen were not significant (p>0.05). Conclusions: After Sun's procedure, aortic remodeling was a continuous process and occurred in a predictable model, and the extent of aortic remodeling varied at different levels. Remodeling in descending thoracic aorta was earlier than it was in abdominal aorta.