Incidence and natural history of isolated abdominal aortic dissection: A population-based assessment from 1995 to 2015.

Background: Isolated abdominal dissection (IAD) is an uncommon clinical problem that is less well-understood than thoracic aortic dissection (AD). We performed a population-based assessment of the incidence, natural history, and treatment outcomes of IAD to better characterize this disease.
Methods: We used the Rochester Epidemiology Project to identify all Olmsted County, MN residents with a diagnosis of AD, 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 (AD, intramural hematoma, or penetrating ulcer), 23 were initially diagnosed with IAD. Nine were reclassified as having a penetrating aortic ulcer and were excluded, leaving 14 patients for review (10 male [71%]; mean age, 71 years). Three patients (21%) were symptomatic (abdominal pain, back pain, hypertension) and none had malperfusion or rupture. Prior aortic dilatation was present in eight patients (57%) and Marfan syndrome in one (7%). Two patients (14%) had iatrogenic IAD. Initial management was medical in 13 and endovascular aneurysm repair in one (symptomatic subacute, infrarenal dissection with small aneurysm). The median clinical and imaging follow-up was 6.7 years (range, 0-17 years). An abdominal aortic aneurysm occurred in eight (six 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 two patients; for severe aortic stenosis with claudication in one (infrarenal aortic stenting) and increasing aortic size in one (open repair). One patient required reintervention (thrombolysis and stenting for endovascular aneurysm repair limb thrombosis). Survival for IAD at 1, 3, and 5 years was 93%, 85%, and 76%, respectively, compared with population controls at 98%, 85%, and 71%, respectively (long rank P = .38). Mortality was due to cardiovascular causes in three patients (21%) and no deaths were aortic related. Major adverse cardiac events occurred in five patients (36%) owing to heart failure.
Conclusions: IAD is rare. The 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. The overall mortality is similar to population controls. Heart failure and cardiac-related death are prevalent, suggesting that close cardiovascular care is needed in this patient population.
(Copyright © 2020 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)