Partial thrombosis of the false lumen influences aortic growth in type B dissection.

In the acute setting, the majority of patients affected by uncomplicated acute type B aortic dissection (ABAD) can be managed with medical therapy. In these patients, inhospital outcome is generally acceptable, with mortality rates of 1-10% (1,2). However, long-term outcomes in this group is less positive, with a mortality rates reported as 2025% within 3 years. Predictors of long-term complications have been a highly debated topic in recent years. Reports from the International Registry of Acute Aortic Dissection (IRAD) have shown that a partially thrombosed false lumen is associated with increased surgical mortality. Among ABAD patients discharged alive, those presenting with a partially thrombosed false lumen had an increased rate of mortality, after adjusting for age, gender and type of in-hospital treatment (3). One hypothesis for this observation is that partial thrombosis of the false lumen may occlude distal re-entry tears (“sac formation”), resulting in higher diastolic pressure (4). The purpose of this study was to determine whether partial thrombosis of the false lumen in ABAD patients is associated with increased aortic expansion (5).