The distance of the primary intimal tear from the left subclavian artery predicts aortic growth in uncomplicated type B aortic dissection

Objective

Controversy exists about the optimal treatment of acute uncomplicated type B aortic dissection (auTBAD). Optimal medical therapy (OMT) provides excellent short-term outcomes, but long-term results are poor. Ideally, auTBAD patients who will fail to respond to OMT in the chronic phase could be identified and undergo thoracic endovascular aortic repair. The purpose of this study was to identify radiographic predictors of auTBAD patients who will fail to respond to OMT.

Methods

A review of the Emory aortic database from 2000 to 2017 identified 320 auTBAD patients initially treated with OMT. From this cohort, 121 patients with two or more contrast-enhanced imaging scans were available for analysis. These patients were initially divided into groups based on growth of the thoracic aorta ≥10 mm or intervention due to aneurysmal growth: growth (n = 72) and no growth (n = 49). TeraRecon (Foster City, Calif) imaging software was used to analyze characteristics of the primary intimal tear (PIT), false lumen, and overall aortic size. Finally, Cox proportional hazards models were constructed to estimate hazard ratios and to identify predictors of OMT failure.

Results

The mean age of all patients was 54 ± 11 years, and 67% were male. Thirty-eight patients (53%) in the growth group underwent intervention. There were no differences between groups in age, hypertension, diabetes mellitus, tobacco abuse, or chronic obstructive pulmonary disease. The distance of the PIT from the left subclavian artery in patients with auTBAD was significantly shorter in the growth group (growth, 27 mm [9-66 mm]; no growth, 77 mm [26-142 mm]; P < .01). Multivariable Cox regression analysis identified the distance of the PIT from the left subclavian artery and a thoracic aortic diameter >45 mm as independent predictors of failure of OMT. Partial false lumen thrombosis was not a predictor of aortic growth.

Conclusions

The distance of the PIT from the left subclavian artery is a predictor of aortic growth in auTBAD. Patients with a primary tear located in zone 3 of the proximal descending thoracic aorta should be monitored closely and may be considered for early thoracic endovascular aortic repair in the setting of auTBAD.