Survival After Endovascular Therapy in Patients With Type B Aortic Dissection: A Report From the International Registry of Acute Aortic Dissection (IRAD)
Is survival after thoracic endovascular repair (TEVAR) better than medical therapy in patients with type B acute aortic dissection (TBAAD)?
TEVAR is increasingly being used in patients with TBAAD, but long-term data on its effectiveness are limited. This was an observational study of 1,129 consecutive patients enrolled at high-volume referral centers in the large International Registry of Aortic Dissection (IRAD), between 1995 and 2012. Of these, 853 (76%) received medical therapy and 276 (24%) received TEVAR. Differences between the groups in terms of patient characteristics, initial treatment and outcomes, and long-term follow-up were analyzed.
Patients who received TEVAR were younger and more often men, but also had more complicated TBAAD (e.g., shock, periaortic hematoma, signs of malperfusion, stroke, spinal cord ischemia, mesenteric ischemia, and/or renal failure). In-hospital and 1-year mortality were similar between the groups; however, patients who received TEVAR had lower mortality at 5 years, based on Kaplan-Meier survival curves.
The authors concluded: “Results from IRAD show that TEVAR is associated with lower mortality over a 5-year period than medical therapy for TBAAD. Further randomized trials with long-term follow-up are needed.”
This study by the IRAD investigators adds new information to a controversial area. There has been dramatic growth in the use of TEVAR for TBAAD despite mixed data supporting its use. The only randomized controlled trial performed in this area (e.g., the INSTEAD trial) showed no differences between uncomplicated patients treated with medical therapy and TEVAR, but that report has been criticized for being underpowered, based on lower than expected event rates at 2 years. This new study by the IRAD investigators is intriguing, although it should not change practice. The inherent limitations of observational studies make it impossible to know if improved survival was due to patient selection or treatment. I agree with the authors that further randomized controlled trials are needed. For now, TEVAR will remain an important treatment option in complicated TBAAD, given the high risks of surgery. In uncomplicated TBAAD, a primary conservative approach is probably still warranted. Treatment of patients with aneurysms following TBAAD should be discussed and individualized at experienced centers.
Keywords: Kaplan-Meier Estimate, Endovascular Procedures, Shock, Hematoma
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