Incidence and Natural History of Isolated Abdominal Aortic Dissection: A Population Based Assessment From 1995-2015

Background: Isolated abdominal dissection (IAD) is an uncommon clinical problem that is less well understood than thoracic aortic dissection. We performed a population based assessment of the incidence, natural history and treatment outcomes of IAD to better characterize this disease.

Methods: We utilized the Rochester Epidemiology Project to identify all Olmsted County, MN residents with a diagnosis of aortic dissection, intramural hematoma or penetrating ulcer (1995-2015). Diagnostic imaging of all patients was reviewed to confirm the diagnosis of IAD for inclusion. Presentation, treatment, and outcomes were reviewed. Survival of IAD patients was compared to age- and sex-matched population controls 3:1.

Results: Of 133 residents with aortic syndrome (aortic dissection, intramural hematoma, or penetrating ulcer), 23 were initially diagnosed with IAD. Nine were reclassified as PAU and excluded, leaving 14 patients for review (10 male (71%), mean age 71 years). Three patients (21%) were symptomatic (abdominal/back pain/ hypertension) and none had malperfusion/rupture. Prior aortic dilatation was present in 8 (57%) and Marfan syndrome in 1 (7%). Two (14%) patients had iatrogenic IAD. Initial management was medical in 13 and EVAR in one (symptomatic subacute, infrarenal dissection with small aneurysm). The median clinical and imaging follow-up was 6.7 (range 0-17 years). An abdominal aortic aneurysm occurred in 8 (6 at the time of IAD diagnosis, one at 2.9 years, and one at 5.2 years after diagnosis). The average growth in the entire cohort was 0.9+0.4 cm, which translated to an average growth rate of 0.09 cm/year. Subsequent intervention was performed in 2; for severe aortic stenosis with claudication in one (infrarenal aortic stenting) and increasing aortic size in one (open repair). One patient required re-intervention (thrombolysis and stenting for EVAR limb thrombosis). Survival for IAD at 1, 3, and 5 years was 93%, 85% and 76% compared with population controls at 98%, 85% and 71% respectively (long rank p= 0.38). Mortality was due to cardiovascular causes in 3 (21%) and no deaths were aortic related. Major adverse cardiac events occurred in 5 (36%) due to heart failure.

Conclusions: Isolated abdominal dissection is rare. Initial management for asymptomatic patients is medical. The aortic growth rate is slow, with no aortic related mortality and a low rate of aortic intervention. Overall mortality is similar to population controls. Heart failure and cardiac related death are prevalent, suggesting close cardiovascular care is needed in this patient population.