Natural History of Splanchnic Artery Aneurysms

Splanchnic artery aneurysms (SAAs) represent a rare and potential life-threatening disease with a documented incidence of 0.1-2.0%. The risk of rupture and the diameter to recommend surgery are still controversial. The purpose of this study was to review surveillance computed tomography scans (CTs) at a high-volume institution in order to better define the natural history of the SAA.

Between January 2000 and February 2019, all SAAs patients in follow-up at a single center institution were selected for analysis. CTs from patients managed nonoperatively and CTs before surgery from patients submitted to surgery were studied. The first CTs were used to determine aneurysm size, morphology, and anatomic characteristics, and the last CTs performed during nonoperative follow-up were used to compare the diameter with the previous CTs. Primary endpoint included growth rate for all SAAs location, and secondary endpoint included the clinical or anatomical characteristic associated with a faster growth rate.

In total, 116 consecutive patients were identified with SAAs and 74 patients with 87 SAAs who had at least 2 CTs during follow-up were analyzed. From those 74 patients, 12 were submitted to surgery and only their preoperative CTs were analyzed. The SAAs' locations were: splenic (55.4%), hepatic (12.2%), superior mesenteric artery (17.6%), celiac trunk (27.0%), gastric and gastroepiploic arteries (1.4%), pancreaticoduodenal and gastroduodenal arteries (4.1%). The median follow-up for all patients was 46.7 months (±35.3), and the median of growth for all aneurysms was 0.63 mm/year (±2.19). Only the splenic aneurysms presented growth with statistic significance of 1.08 mm per/year (±1.99) (P < 0.001). Only portal hypertension showed statistically significance to splenic aneurysm growth (P = 0.002). Multivariate analysis for variables associated with splenic aneurysm growth ≥1 mm/year showed that portal hypertension was the only variable with statistical significance (P < 0.01, IC 95% 2.0-186.9, β = 19.5).

Although longer-term follow-up and larger sample size are needed to better understand the natural history of SAAs, the majority of SAAs tends to remain stable in size through follow-up. Portal hypertension was the only risk factor found for true splenic aneurysm growth, and so those patients must have a closer follow-up.