Type B Aortic Dissections: Treating the Many to Benefit the Few?

Purpose: It is now more than a decade since aortic stent-grafts were introduced clinically to provide a less invasive and potentially less harmful therapeutic option to treat type B aortic dissections. However, recent publications on best medical treatment and quality of life in patients with chronic type B dissection support conservative treatment due to the low incidence of aneurysm formation, rupture, and disease-related complications. Against this backdrop, we analyzed our experiences and now discuss whether the availability of endografts allowed us to change indications toward a more aggressive endovascular approach to acute and non-complex type B dissections, seeking to determine which patients we should treat and which ones we should observe.

Methods: Between 1997 and 2008 in our institution in Heidelberg, we treated 172 patients with acute and chronic type B dissections, most (n = 118, 69%) conservatively. However, 54 patients (40 men; mean age 57 years, range 30-82) underwent endovascular repair; 43% (n = 23) were emergency cases. Patients were followed periodically with computed tomographic angiography.

Results: Correct stent-graft deployment was achieved in 50 (93%) patients; the left subclavian artery was intentionally covered in 30 (55%) cases. Two carotid-subclavian bypass grafts were performed at the time of the endovascular repair due to partial coverage of the left common carotid artery. The perioperative complication rate was 19% (n = 10), but there were no neurological sequelae. The 30-day mortality rate was 11% (n = 6). Over a mean 32.1+/-25 months, 4 other patients died (18.5% overall mortality rate); survival estimates by Kaplan-Meier analysis were 80.4% and 66.1% after 1 and 5 years, respectively. Complete false lumen thrombosis was observed in 32 (60%) and a persisting completely patent false lumen in 3. The aortic expansion rate was 31% (17/54) overall. No difference was found between acute and chronic dissections in terms of survival (p = 0.247).

Conclusion: Despite a minimally invasive approach, complication and mortality rates for endovascular therapy of type B aortic dissections are considerable. Endografting is limited to symptomatic patients and those with chronic large aneurysmal expansion. At this stage in stent-graft development, asymptomatic patients benefit more from conservative treatment.