Effects of the patent false lumen on the long-term outcome of type B acute aortic dissection.

Objective: To determine the most effective treatment, we performed a detailed comparative study of the clinical course of patients with type B aortic dissection with a patent or thrombosed false lumen who did not undergo surgery in the acute period. We examined the effect of patency of the false lumen on outcome.

Methods: Computed tomography scans of 138 patients with type B acute aortic dissection were reviewed. Of 138 patients, 110 were medically treated and survived the acute period. We focused on the outcome of these 110 patients, 62 with medically treated thrombosed false lumen (thrombosed group) and 48 with medically treated patent false lumen (patent group). We investigated factors influencing outcome among the 110 patients. The follow-up period was up to 10 years after the onset of aortic dissection. The three study endpoints were death from any cause, dissection-related death (aortic rupture, perioperative death, or death due to organ ischemia), and a dissection-related event (aortic rupture or surgery). In the patent group, we investigated factors influencing long-term outcome.

Results: Patency of the false lumen was an independent risk factor for dissection-related death (P = 0.038, hazard ratio=5.6, confidence interval=1.1-28) and for a dissection-related event (P = 0.000, hazard ratio=7.6, confidence interval=2.7-22) but not for death from any cause (P = 0.769, hazard ratio=1.2, confidence interval=0.45-2.91). In the patent group, location of the most dilated aortic segment at the distal arch was an independent risk factor for dissection-related death (P = 0.026, hazard ratio=13.6, confidence interval=1.4-135) and for a dissection-related event (P = 0.048, hazard ratio=2.6, confidence interval=1.0-6.9).

Conclusions: Patency of the false lumen is a strong independent prognostic factor for type B aortic dissection. Location of the most dilated aortic segment at the distal arch is a significant risk factor in the patients with a patent false lumen.