Computed Tomography Predictors of Type B Aortic Dissection

Study Questions:

Can computed tomography (CT) findings identify patients with uncomplicated acute type B aortic dissections who are more likely to have delayed intervention?

Methods:

This retrospective study examined 117 patients with uncomplicated acute type B aortic dissections with follow-up imaging and without urgent repair. A total of 85 patients did not have intervention, while 32 had delayed intervention. The aortic diameter, true lumen volume (TLV), false lumen volume (FLV), and total aorta volume from the left subclavian artery to the celiac artery was measured, and measurements were compared between patients who had a delayed intervention versus those who had no intervention.

Results:

Between patients with no (n = 85) vs. delayed intervention (n = 32), there were differences in maximal aortic diameter (p = 0.047), FLV (p < 0.001), and ratio of TLV/FLV (p < 0.001); there was no difference in TLV between groups (p = 0.39). Between groups with TLV/FLV ratio <0.8, 0.8-1.6, vs. >1.6, there were differences in growth rates (4.6 vs. 2.4 vs. 0.8 mm/month, p < 0.03). A TLV/FLV ratio <0.8 was associated with an odds ratio of 12.2 (95% confidence interval, 5-26; p < 0.001) for undergoing intervention. Survival free of aortic intervention at 1 and 2 years was 60% and 42% for ratio <0.8, and 92% and 82% for ratio >1.6, respectively (p = 0.001).

Conclusions:

A low TLV/FLV ratio is associated with a higher rate of aortic growth and increased rate of delayed aortic interventions.

Perspective:

A large proportion of patients with uncomplicated acute type B aortic dissection experience increased aortic size and/or require delayed intervention, although it remains challenging to identify these individuals. This retrospective study finds that patients with a low TLV/FLV ratio on baseline imaging have increased rates of aortic growth and experience a 12-fold increase in the rate of delayed intervention. These data suggest that we may be able to use the baseline CT to help predict which patients may require intervention. These results are promising, although they need to be validated prospectively. Incorporation of these measurements in future treatment studies could determine whether these findings could be used to improve patient outcomes.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Vascular Medicine, Aortic Surgery, Interventions and Imaging, Interventions and Vascular Medicine, Computed Tomography, Nuclear Imaging

Keywords: Aneurysm, Aneurysm, Dissecting, Aortic Aneurysm, Thoracic, Cardiovascular Surgical Procedures, Diagnostic Imaging, Tomography, Tomography, X-Ray Computed, Vascular Diseases


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