Histological analysis of aortic dissections following previous cardiovascular surgery

BackgroundAortic dissections have been reported as a rare complication post-cardiovascular surgery due to areas of cross clamping, suture lines and cannulation sites as locations for peri-operative injury. This study aimed to review the histological features of aortic tissues of 11 patients with aortic dissections who underwent previous cardiovascular surgery and to identify evidence of trauma within the area of surgery.MethodsA review of our records from January 2000 to July 2005 showed that 11 patients had developed a postoperative aortic dissection. Surgically excised aortic tissues were obtained either at surgery or at autopsy for further gross and histological analysis. Clinical records were also reviewed for relevant history.ResultsThe mean age of the 11 patients in this study was 60.1±12.5 years. The year of index surgery for all patients was between 1960 and 2005, and the interval between index surgery and admission for re-operation was 13.8±12.9 years (range, 1 day to 45 years). Five patients (45%) demonstrated aortic intimal thickening, two of which showed evidence of atherosclerotic plaques. Three (27%) exhibited cystic medial change. All cases showed mild to moderate medial changes near or at the site of traumatic injury, as demonstrated by a sharp discontinuity in the media of the aorta. Other than the four aortic tissues obtained at autopsy, long-term follow-up for the remaining patients was not obtained.ConclusionEvidence of previous trauma in close proximity to cannulation, cross-clamping and/or aortotomy sites was found in all patients in this series. All deaths in this series were found in the acute group rather than in the chronic group. It is important that the occurrence of dissections in patients undergoing previous cardiac surgery be not only reported, but analyzed by both the clinician and the pathologist. Hopefully, these efforts may identify particular patient risk factors and clarify preventative measures peri-operatively which may decrease the incidence of these potentially lethal complication.