The fate of unrepaired chronic type A aortic dissection

The current guidelines do not consider chronic type A aortic dissection as one of the triggers for prophylactic aortic repair, and an aortic diameter of 55 mm is considered the threshold for surgery.

From the institutional database, we retrieved 82 patients who were diagnosed as having chronic type A aortic dissection but did not undergo immediate surgical repair from 1997 to 2016. The primary outcome was a composite of adverse aortic events defined as aortic rupture and sudden death. Conversion to elective surgery during follow-up was regarded as competing risk for adverse events.

The median value of the maximal aortic diameter at baseline was 55.2 mm. During a median follow-up of 77.1 months, 19 adverse events occurred while 9 patients received elective aortic repair. On multivariable competing risk analyses, baseline aortic diameter and age emerged as significant and independent factors associated with aortic events. The estimated rates of aortic event within 5 years were 12.0%, 19.4%, and 29.7% for aortic diameters of 50, 60, and 70 mm, respectively, with escalating risk rates as age increased for the given aortic diameters.

In unrepaired chronic type A aortic dissection, aortic events were not infrequent even for patients with an aortic diameter of less than 55 mm. This finding indicates that there may be a need to lower the surgical threshold for chronic type A aortic dissection.