A giant left internal iliac artery aneurysm in a patient with Loeys–Dietz syndrome

Abstract

A 16-year-old female presented with left iliac fossa pain. In January 2021, she was admitted to her local hospital with severe lower abdominal pain and the pelvic ultrasound demonstrated a 13-cm left internal iliac artery dissecting aneurysm with its partial thrombosis. On examination, she had a high-arched palate, multiple skin stretch marks, flat feet and a soft systolic ejection murmur at the left 5th mid-clavicular line. She had a mildly tender abdomen in the left iliac fossa. Computed tomography angiography demonstrated a 12.2 cm × 10.4 cm × 12.5 cm left internal iliac artery aneurysm. During surgery, the aneurysm was incised and the proximal and distal orifices of the internal iliac artery were ligated. Genetic testing yielded 2 mutations in the SMAD3 gene characteristic for Loeys–Dietz syndrome.

Isolated iliac artery aneurysms are rare with an incidence in an autopsy study of 0.03%.

Isolated iliac artery aneurysms are rare with an incidence in an autopsy study of 0.03%. Forty percent of these patients presented with acute haemorrhage secondary to aneurysm rupture, which is associated with 50–100% mortality. We describe a patient with Loeys–Dietz syndrome (LDS) complicated by a dissected giant internal iliac artery aneurysm (IIAA) who underwent successful surgical treatment.

Ms. M, a 16-year-old female, was referred to our hospital with constant left iliac fossa pain of 4 months duration. In January 2021, she was admitted to her local hospital with severe lower abdominal pain and the pelvic ultrasound revealed a 13-cm dissecting left IIAA with its partial thrombosis. She was a second child of her parents and denied any family history of aortic or large arterial vessel dissection as well as a history of trauma. On examination, the patient's vital signs were stable, her height was 173 cm, and her weight was 80 kg. She had a high-arched palate, multiple skin stretch marks, flat feet, and a soft systolic ejection murmur at the left 5th mid-clavicular line. Her abdomen was soft and mildly tender on deep palpation in the left iliac fossa. Blood tests showed mild anaemia, haemoglobin concentration of 105 g/l, normal white blood cell and C-reactive protein concentration of 25 mg/l (normal range: 0–5 mg/l). The patient had a normal estimated glomerular filtration rate.

Computed tomography angiography revealed a partially thrombosed left IIAA, 12.2 cm × 10.4 cm × 12.5 cm, which occupied most of the lower pelvis (Fig. 1A). Transthoracic echocardiography demonstrated normal left ventricular function, a 4-mm prolapse of the anterior leaflet of the mitral valve with a peak gradient of 3 mmHg, and minimal regurgitation. The aorta was 30 mm in diameter at the sinuses of Valsalva, 29 mm in the ascending aorta, 24 mm in the aortic arch and 19 mm in the aortic isthmus. Pulmonary and tricuspid valves had mild regurgitation. During surgery, a left postero-lateral retroperitoneal approach was used for access to the left iliac arteries. The left internal iliac artery was aneurysmal and severely enlarged. Following administration of heparin, the left common iliac and the left distal external iliac arteries were occluded with vascular clamps. A 10-cm incision was made in the anterolateral wall of the left IIAA. The aneurysm contained a large amount of fresh and old blood clots. Blood and blood clots were evacuated from the aneurysm (Fig. 1B). The distal orifice of the left internal iliac artery was identified and oversewn with a 4–0 polypropylene suture from within the aneurysm. Analogously, the proximal orifice of the left internal iliac artery was sutured with a 4–0 polypropylene suture. The vascular clamps were removed from the arteries. The wound was drained and closed in layers. The postoperative period was uncomplicated.

Figure 1:

(A) Computed tomography angiography revealed a partially thrombosed left internal iliac artery aneurysm, 12.2 cm × 10.4 cm × 12.5 cm, which occupied most of the lower pelvis. (B) The wall of the left internal iliac artery aneurysm was incised. The aneurysm contained a large amount of fresh and old blood clots.

Genetic testing yielded 2 mutations in the SMAD3 gene characteristic for type III LDS.

LDS is an autosomal dominant connective tissue disorder that is caused by an inherited or de novo heterozygous mutation in the transforming growth factor-beta receptors 1 and 2 genes. This leads to increased transforming growth factor-beta signalling and degenerative changes in the vascular wall, development of aneurysms in the aorta and large arteries, aneurysms dissection and rupture [1].

Our case emphasizes the importance of diagnosing young patients with arterial aneurysms with an inherited connective tissue disorder that requires the patient's family screening and counselling, close follow-up, treatment with angiotensin II receptor antagonists such as Losartan and monitoring for the development of new cardiovascular complications.

Conflict of interest: none declared.

Reviewer information

Interactive CardioVascular and Thoracic Surgery thanks Kanat Ozisik and the other, anonymous reviewer(s) for their contribution to the peer review process of this article.