Few Internal Iliac artery Aneurysms Rupture under 4 cm

• ObjectiveThis study investigated the diameter of internal iliac artery (IIA) aneurysms (IIAAs) at the time of rupture to evaluate whether the current threshold diameter for elective repair of 3 cm is reasonable. The prevalence of concomitant aneurysms and results of surgical treatment were also investigated.MethodsThis was a retrospective analysis of patients with ruptured IIAA from seven countries. The patients were collected from vascular registries and patient records of 28 vascular centers. Computed tomography images taken at the time of rupture were analyzed, and maximal diameters of the ruptured IIA and other aortoiliac arteries were measured. Data on the type of surgical treatment, mortality at 30 days, and follow-up were collected.ResultsSixty-three patients (55 men and 8 women) were identified, operated on from 2002 to 2015. The patients were a mean age of 76.6 years (standard deviation, 9.0; range 48-93 years). A concomitant common iliac artery aneurysm was present in 65.0%, 41.7% had a concomitant abdominal aortic aneurysm, and 36.7% had both. IIAA was isolated in 30.0%. The mean maximal diameter of the ruptured artery was 68.4 mm (standard deviation, 20.5 mm; median, 67.0 mm; range, 25-116 mm). One rupture occurred at <3 cm and four at <4 cm (6.3% of all ruptures). All patients were treated, 73.0% by open repair and 27.0% by endovascular repair. The 30-day mortality was 12.7%. Median follow-up was 18.3 months (interquartile range, 2.0-48.3 months). The 1-year Kaplan-Meier estimate for survival was 74.5% (standard error, 5.7%).ConclusionsIIAA is an uncommon condition and mostly coexists with other aortoiliac aneurysms. Follow-up until a diameter of 4 cm seems justified, at least in elderly men, although lack of surveillance data precludes firm conclusions. The mortality was low compared with previously published figures and lower than mortality in patients with ruptured abdominal aortic aneurysm.Abdominal aortic aneurysm (AAA) is the most common and studied aneurysm. Aneurysms of the iliac arteries are found considerably less often, and epidemiologic data on these do not exist. In many cases iliac artery aneurysms coexist with aortic aneurysms: ∼10% to 20% of patients with AAA also have a concomitant aneurysm in the iliac arteries.1 The artery most often affected is the common iliac artery (CIA), followed by the internal iliac artery (IIA), also called the hypogastric artery. In the case of isolated aneurysms in the iliac arteries, without involvement of the aorta, the most common location is the IIA.2 Aneurysms of the external iliac artery are extremely rare, possibly because these arteries originate later in development from a different cell population than the distal aorta and the CIA and IIA. Studies on IIA aneurysms (IIAAs) are scarce owing to the rarity of the condition. The existing literature consists primarily of case reports and small patient series. No prospective studies on IAAs exist.According to the literature, IAAs have a high rupture and mortality rate even in elective cases, possibly because of their deep location in the pelvis.3 The etiology and risk factors of IAA seem to be the same as AAA.4 Iliac aneurysms are mostly degenerative but can also be mycotic or caused by genetic disorders such as Marfan or Ehlers-Danlos syndromes. Traumatic aneurysms in the iliac arteries have also been described; for example, caused by iatrogenic trauma from hip, lumbar, or gynecologic operations. A mainly historical subpopulation of young women with IIAA caused by trauma from pregnancy and delivery has been described.5 and 6IAAs cause symptoms more often than AAA because of compression of pelvic structures such as ureters, bladder, veins, or lumbar nerves. Wilhelm et al7 reported that 53% of published isolated IIAA cases were symptomatic, not including the ruptured ones (31%). The high proportion of symptomatic patients in these older reports may partly be explained, however, by the fact that most of these cases were from time before widespread use of modern imaging. IIAA are not easily discovered with clinical examination because of their location8 but are detected increasingly often as a result of imaging and screening programs.Because the studies on IIAAs are scarce, the natural history is virtually unknown. A widely used threshold for elective repair is 3 cm, originally suggested by McCready et al9 because their series did not include any ruptures under that diameter. However, only seven ruptures were included in that report. The reference list of this article illustrates that most of the papers on this subject were published when open repair was the only treatment option. Nowadays endovascular treatment is the first option in many centers.10The aim of this study was to investigate at what diameter IIAAs tend to rupture and whether the current operative threshold of 3 cm is rational. Secondary aims were to assess the prevalence of concomitant aortoiliac aneurysms, treatment patterns, and the results of treatment.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Kirurgi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Surgery (hsv//eng)

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art (subject category)