Thoracic Aortic Aneurysms

Remarkable progress has been made in the surgical treatment of thoracoabdominal aortic aneurysms. The decline in mortality and complication rates can be attributed to improvements in perioperative care and in surgical technique, particularly the adoption of adjunct distal aortic perfusion and cerebrospinal fluid drainage. Neurologic deficit is no longer a major threat to patients, as the use of adjuncts has brought the incidence down to 2.4% for all thoracoabdominal aortic aneurysms. However, we continue to pursue research to improve organ preservation, particularly for the most troublesome extent II thoracoabdominal aortic aneurysm.     

Endovascular Stent Grafting of Thoracic Aortic Aneurysms

In an effort to decrease the morbidity of conventional open thoracic aortic aneurysm repair, we have witnessed in the last 10 years an expansion in the use of stent grafts as an alternative treatment option. This approach has provided a treatment option for patients with multiple medical comorbidities who may otherwise have been considered excessively high risk for standard open reconstruction. Results have identified promising procedural success while limiting complications and mortality rates. A review of contemporary results as well as patient and device characteristics is the focus of this article.     

Natural History of Arteriosclerotic Thoracic Aortic Aneurysms

Out of 28 patients with arteriosclerotic aortic aneurysm seen between 1965 and 1975, 22 were not surgically repaired. Of these 22 patients, 9 subsequently died of rupture and 7 of unrelated cardiovascular disease, and 6 are living at the time of this study. Mean survival for the group is less than 3 years. All but 1 rupture occurred in aneurysms larger than 10 cm, and recent increase in size preceded rupture in all patients for whom serial roentgenograms were available.This study documents the high risk of rupture of arteriosclerotic aortic aneurysms of the descending thoracic aorta and suggests a more uniform use of surgical management depending on the patient's age and underlying state of health.     

Simultaneous Operations for Combined Thoracic and Abdominal Aortic Aneurysms

Purpose. To assess whether simultaneous operations are appropriate for combined thoracic and abdominal aortic aneurysms.Methods. Simultaneous operations were performed for combined thoracic and abdominal aortic aneurysms in nine patients. The thoracic aortic aneurysm (TAA) was repaired first, followed by repair of the abdominal aortic aneurysm (AAA). Selective cerebral perfusion was used in eight patients, after the exception of one who underwent replacement of the ascending aorta under hypothermic circulatory arrest. The abdominal organs were perfused during distal anastomosis in surgery for Stanford type A aortic dissection or aortic arch aneurysm; via the femoral artery with an aortic balloon occlusion catheter in one patient, and via an occlusion catheter with a perfusion lumen in two patients.Results. All patients underwent planned simultaneous repair of the AAA. One of the patients who underwent simultaneous replacement of both the descending thoracic and abdominal aorta was left with paraplegia, and one patient died suddenly of massive hemoptysis and melena on the 29th postoperative day. Autopsy revealed that the bleeding had been caused by aorto-broncho-esophageal fistulae. The overall operative mortality was 11%.Conclusions. Simultaneous repair of combined TAA and AAA can be safely performed; however, the risk of paraplegia should be considered, especially with simultaneous repair of concomitant aneurysms of the descending thoracic and abdominal aorta.     

Endovascular Grafts in the Treatment of Thoracic Aortic Aneurysms and Pseudoaneurysms

The purpose of this study was to describe our experience with balloon and self-expanding endovascular grafts for the management of thoracic aortic lesions. Between February 1997 and June 1998, 20 endovascular grafts were implanted in 14 patients for the treatment of thoracic aortic aneurysms and pseudoaneurysms. Endovascular procedures were performed using one of four different devices: (1) Dacron-covered balloon-expandable Palmaztrade mark stent, (2) balloon-expandable Palmaz stent-PTFE graft prosthesis (BE-PS), (3) self-expanding internally supported Nitinol Dacron prosthesis (Vanguardtrade mark SE-V), and (4) self-expanding externally supported Nitinol PTFE prosthesis (Excludertrade mark SE-E). The results show that endovascular grafting represents a potentially important alternative therapy to open repair of the thoracic aorta. Self-expanding devices were, in our experience, easier to use and more accurately deployed.     

Prospective Study of the Natural History of Thoracic Aortic Aneurysms

Background. The decision whether or not to recommend resection of moderately large descending thoracic and thoracoabdominal aneurysms requires weighing the relatively high mortality and significant risk of paraplegia associated with operation against the likelihood that the aneurysm will rupture spontaneously, with an almost invariably fatal outcome. To better define the risk of aneurysm rupture, we undertook a prospective study of patients who had not had operation on their moderately large descending thoracic and thoracoabdominal aneurysms.

Methods. Patients were enrolled at the time of their second computed tomographic scans: three-dimensional computer-generated reconstructions allowed determination of several dimensional parameters for each study, including diameters and cross-sectional areas at the site of maximal dilatation in the descending aorta and in the abdomen as well as total thoracoabdominal surface area. Comparisons of serial studies permitted calculation of yearly rates of change in these dimensions.

Results. Of 114 patients, 8 died of causes unrelated to the aneurysm, 26 died of rupture, 20 met previously determined criteria for operation, and 60 survived without operation or rupture. Multivariate regression analysis identified maximal diameter in the descending and in the abdominal aorta as independent risk factors for rupture, as well as older age, the presence of even uncharacteristic pain, and a history of chronic obstructive pulmonary disease. A piecewise exponential model enabled construction of an equation allowing calculation of rate of rupture in patients in whom the values of the risk factors are known, and also of the probability of rupture in a given individual over a specified time interval.

Conclusions. Because using this equation--based on easily determined risk factors (age, pain, chronic obstructive pulmonary disease, maximal thoracic and maximal abdominal aortic diameter)--allows the risk of aneurysm rupture within a given interval to be estimated fairly accurately for each individual patient, it is our current practice to recommend operation when the calculated risk of rupture within 1 year exceeds the anticipated mortality of elective operation, rather than relying on general operative guidelines based almost exclusively on aneurysm size.     

Prevalence of Thoracic Aortic Aneurysms in Patients with Degenerative Abdominal Aortic Aneurysms: Results from the Prospective ACTA Study

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