Prediction of progression or regression of type A aortic intramural hematoma by computed tomography

Background-It has been reported that early surgery should be required for p atients with type A aortic intramural hematoma (IMH) because it tends to de velop classic aortic dissection or rupture. However, the anatomic features of type A IMH that develops dissection or rupture are unknown. The purpose of this study was to investigate the predictors of progression or regressio n of type A IMH by computed tomography (CT). Methods and Results-Twenty-two consecutive patients with type A IMH were st udied by serial CT images. Aortic diameter and aortic wall thickness of the ascending aorta were estimated in CT images at 3 levels on admission and a t follow-up (mean 37 days). We defined patients who showed increased maximu m aortic wall thickness in the follow-up CT (n = 9) or died of rupture (n = 1) as the progression group (n = 10). The other 12 patients, who all showe d decreased maximum wall thickness, were categorized as the regression grou p. In the progression group, the maximum aortic diameter in the initial CT was significantly greater than that in the regression group (55 +/- 6 vs 47 +/- 3 mm, P = 0.001). A Cox regression analysis revealed that the maximum aortic diameter was the strongest predictor for progression of type A IMH. We considered the optimal cutoff value to be 50 mm for the maximum aortic d iameter to predict progression (positive predictive value 83%, negative pre dictive value 100%). Conclusions-Maximum aortic diameter estimated by the initial CT. images is predictive for progression of type A IMH.