Videodensitometric blood flow analysis of abdominal aortic aneurysm and intravascular coagulation

We investigated the relation between flow pattern in abdominal aortic aneurysm (AAA) and intravascular coagulopathy characterized by increased fibrin degradation product d-dimer (FDP-DD) or thrombin-antithrombin complex (TAT). Materials and methods The ratio of AAA maximum endoluminal diameter (diameter of flow channel) (n = 23) to diameter of the aorta between the superior mesenteric and renal arteries (R ratio) was measured with three-dimensional computed tomography angiography. Digital subtraction angiography was performed with 20 mL (10 mL/s) of contrast agent injected from the suprarenal portion of the abdominal aorta. The duration between the time when average gray scale in the AAA reached maximum and average region of interest gray scale decreased to half-maximum (bolus transit time in AAA [BTT(AAA)]) was calculated.

Single correlation coefficient with statistic significance was detected between R ratio and BTT(AAA) (BTT(AAA) = 2.54 x R ratio + 3.65; r(2) =.30; P =.042). Among the three-dimensional morphologic and videodensitometric variants, BTT(AAA) was the most determinant factor associated with FDP-DD (FDP-DD = - 8.647 + 2.029 x BTT(AAA); r(2) =.448; P =.005). The most efficient predictors for TAT were maximum AAA endoluminal diameter (R(endomax)) and BTT(AAA) (TAT = - 14.007 + 2.102 x BTT(AAA) + 0.296 x R(endomax), r(2) =.360; P =.0069).

Our findings suggest a close link between abnormal flow pattern in AAA and activation of the coagulation-fibrinolysis system. Videodensitometric blood flow analysis can be useful in investigation of the pathophysiology of phenomena related to abnormal flow field in AAA.