Computer-aided 3-dimensional visualization of abdominal aortic aneurysms from CT images

Risk factors for rupture of abdominal aortic aneurysm based on three-dimensional study

PURPOSE

Factors influencing the development or rupture of abdominal aortic aneurysms (AAAs) have not yet been confirmed. This study delineated the risk factors for rupture of AAAs as evaluated by means of a combination of three-dimensional (3D) reconstruction and clinical data analysis.

METHODS

The study population comprised Japanese patients in whom an atherosclerotic AAA had been diagnosed between January 1980 and December 1997. We obtained 3D-based data by means of computer-aided 3D reconstruction from computed tomography studies of AAAs. The data included the tortuosity of the aneurysm, maximum transverse diameter, length of the aneurysm, aneurysmal volume, aneurysmal surface area, largest aneurysmal cross-sectional area, ratio of transverse aneurysmal diameter to the length of the aneurysm (T/L), and amount of mural thrombus. Clinical data were collected from patient files. All data were assessed by means of multivariate analysis for their predictive value for expansion or rupture of AAA.

RESULTS

The most efficient predictor of annual expansion rate of maximum transverse diameter (EX-D) was a combination of largest aneurysmal cross-sectional area, tobacco use, and tortuosity. The most efficient predictor of annual expansion rate of aneurysmal volume (EX-V) was a combination of aneurysmal volume and blood urea nitrogen level. The most efficient predictors of aneurysmal rupture was a combination of EX-D, diastolic blood pressure, and T/L.

CONCLUSION

Three-dimensional-based data on aneurysmal morphology, including T/L, largest aneurysmal crosssectional area, and aneurysmal volume, had strong predictive value for expansion and rupture of AAAs.

Perioperative changes in coagulative and fibrinolytic function during surgical treatment of abdominal aortic aneurysm and arteriosclerosis obliterans

To determine the factors which influence perioperative coagulative and fibrinolytic function, we studied 41 patients who underwent surgical repair of unruptured abdominal aortic aneurysm (AAA) and 30 patients who underwent arterial reconstruction for arteriosclerosis obliterans (ASO). In patients with AAA, the levels of fibrin/fibrinogen degradation products (FDP) (11.4 +/- 20.1 micrograms/ml), thrombin-antithrombin III complex (TAT) (22.0 +/- 21.8 micrograms/l), plasmin-alpha 2 plasmin inhibitor complex (PIC) (2.6 +/- 2.9 micrograms/ml) and d-dimer of cross-linked fibrin degradation products (D-D) (8.4 +/- 10.8 micrograms/ml) were elevated, particularly when the AAAs had a large mural thrombus surface area or were accompanied by aneurysm of the iliac or femoral artery. In arterial aneurysms, blood coagulability and secondary fibrinolytic activity were believed to be enhanced. In patients with ASO, the level of TAT (17.2 +/- 24.8 micrograms/l) was so elevated that they were considered to show chronic hypercoagulability. Among the ASO patients with aorto-iliac lesions, those with concomitant graft occlusion or anastomotic aneurysm had significantly elevated levels of TAT. Proximal arterial occlusion or accompanying aneurysm in the ASO patients was associated with increased levels of PIC and D-D. Postoperative fluctuations in conventional hematological variables did not differ significantly among the surgical procedures. Conventional markers showed a transient decrease due to consumption during surgery, and a subsequent recovery or an actual increase within several days after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)