CHICAGO – Guidelines for the management of splanchnic artery aneurysms have been hard to come by because of their rarity, but investigators at Massachusetts General Hospital and Harvard Medical School, both in Boston, have surveyed their 20-year experience to conclude that surveillance is appropriate for most cases of aneurysms smaller than 25 mm, and selective open or endovascular repair is indicated for larger lesions, depending on their location.
“Most of the small splanchnic artery aneurysms (SAAs) of less than 25 mm did not grow or rupture over time and can be observed with axial imaging every 3 years,” Mark F. Conrad, MD, reported at a symposium on vascular surgery sponsored by Northwestern University.
Dr. Mark Conrad
The predominant sites of aneurysm were the splenic artery (95, 36%) and the celiac artery (78, 30%), followed by the hepatic artery (34, 13%), pancreaticoduodenal artery (PDA; 25, 9.6%), superior mesenteric artery (SMA; 17, 6%), gastroduodenal artery (GDA; 11, 4%), jejunal artery (3, 1%) and inferior mesenteric artery (1, 0.4%).
Surveillance consisted of imaging every 3 years. Of the surveillance cohort, 138 patients had longer-term follow-up. The average aneurysm size was 16.3 mm, “so they’re small,” Dr. Conrad said. Of that whole group, only 12 (9%), of SAAs grew in size, and of those, 8 were 25 mm or smaller when they were identified; 8 of the 12 required repair. “The average time to repair was 2 years,” Dr. Conrad said. “There were no ruptures in the surveillance cohort.”
Among the early repair group, 13 (14.7%) had rupture upon presentation, 3 of which (23%) were pseudoaneurysms. The majority of aneurysms in this group were in either the splenic artery, PDA, or GDA. “Their average size was 31 mm – much larger than the patients that we watched,” he said. A total of 70% of all repairs were endovascular in nature, the remainder open, but endovascular comprised a higher percentage of rupture repairs: 10 (77%) vs. 3 (23%) that underwent open procedures.
The outcomes for endovascular and open repair were similar based on the small number of subjects, Dr. Conrad said: 30-day morbidity of 17% for endovascular repair and 22.2% for open; and 30-day mortality of 3.5% and 4.5%, respectively. However, for ruptured lesions, the outcomes were starkly significant: 54% morbidity and 8% mortality at 30 days.
The researchers performed a univariate analysis of predictors for aneurysm. They were aneurysm size with an odds ratio of 1.04 for every 1 mm of growth; PDA or GDA lesions with an OR of 11.2; and Ehlers-Danlos type IV syndrome with an OR of 32.5. The latter included all the three study patients with Ehlers-Danlos syndrome.
Among patients who had splenic SAAs, 99 (93%) were asymptomatic and 5 (5.3%) had pseudoaneurysm, and almost half (47) went into surveillance. Over a mean observation period of 35 months, six (12.8%) grew in size, comprising half of the growing SAAs in the observation group. Thirty-two had endovascular repair and four open repair, with a 30-day morbidity of 22% and 30-day mortality of 2.7%.
Celiac SAAs proved most problematic in terms of symptomatology; all 78 patients with this variant were asymptomatic, and 12 (15%) had dissection. Sixty patients went into surveillance with a mean time of 43 months, and three (5) had aneurysms that grew in size. Five had intervention, four with open repair, with 30-day morbidity of 20% and no 30-day mortality.
Hepatic SAAs affected 34 study subjects, 29 (85%) of whom were asymptomatic, 4 (15%) who had dissection, and 7 (21%) with pseudoaneurysm. Eleven entered surveillance for an average of 28 months, but none showed any aneurysmal growth. The 16 who had intervention were evenly split between open and endovascular repair with 30-day morbidity of 25% and 30-day morality of 12.5%.
The PDA and GDA aneurysms “are really interesting,” Dr. Conrad said. “I think they’re different in nature than the other aneurysms,” he said, noting that 12 (33%) of these aneurysms were symptomatic and 6 (17%) were pseudoaneurysms. Because of the high rate of rupture of PDA/GDA aneurysms, Dr. Conrad advised repair at diagnosis: “97% of these patients had a celiac stenosis, and of those, two-thirds were atherosclerosis related and one-third related to the median arcuate ligament compression.” The rupture rate was comparatively high – 20%. Twenty cases underwent endovascular repair with a 90% success rate while four cases had open repair. Thirty-day morbidity for intact lesions was 11% with no deaths, and 50% with 14% mortality rate for ruptured lesions.
Of the SMA aneurysms in the study population, only 17% were mycotic with the remainder asymptomatic, Dr. Conrad said. Nine underwent surveillance, with one growing in size over a mean observation period of 28 months, four had open repair, and two endovascular repair. Morbidity was 17% at 30 days with no deaths.
The guidelines Dr. Conrad and his group developed recommend treatment for symptomatic patients and a more nuanced approach for asymptomatic patients, depending on the location and size of SAA. All lesions 25 mm or smaller, except those of the PDA/GDA, can be observed with axial imaging every 3 years, he said; intervention is indicated for all larger lesions. Endovascular repair is in order for all splenic SAAs in pregnancy, liver transplantation, and pseudoaneurysm. For hepatic SAAs, open or endovascular repair is indicated for pseudoaneurysm, but open repair only is indicated for asymptomatic celiac SAAs with pseudoaneurysm. Endovascular intervention can address most SAA aneurysms of the PDA and GDA.
Dr. Conrad disclosed he is a consultant to Medtronic and Volcano and is a member of Bard’s clinical events committee.