Chapter review: anastomotic aneurysms

Incidence 30 year experience 6090 aorto-iliofemoral anastomoses 2.4% femoral arteries, 0.4% aorta, 0.8% iliac arteries 20 year follow-up of 518 with ultrasonography or angiography 13.6% femoral arteries, 4.8% aorta, 6.3% iliac arteries

Etiology Suture line disruption Anastomic strength depends of suture coaptation of the graft to vessel wall Silk, very high rate of anastomotic aneurysms within 5 to 10 years when used with prosthetic grafts Dacron, good strength but poor incorporation, persistent inflammatory reaction, and suture ‘drag’

Etiology Nylon, lose significant amount of tensile strength, but readily formable to thin sutures 9-0 and 10-0, lack of brittle qualities PTFE, little inflammatory reaction, does not have same cross-sectional strength as polypropylene Polypropylene, minimally reactive, incorporates into tissue well, maintains strength over time, low coefficient of friction, resistant to bacterial films

etiology Nonsuture methods of anastomosis Adhesives, stents, rings, vascular clips, and laser welding Vascular clips promising for autogenous tissue anastomoses not involving an endarterectomy

etiology – graft failure Earlier generations of PTFE and dacron found to fail over time Possibility of edge fraying of woven velour dacron grafts Take big bites or thermally seal edges

Etiology – arterial wall failure Can deteriorate and lead to pseudoaneurysm Difficult to determine if false or true aneurysm by imaging Assume lesion is a pseudoaneurysm for surgical planning

Etiology - inflammation 45 pseudoaneurysms Bacterial cultures positive for 60% of cases 89% of cases were coagulase neg staph

Etiology – technical errors Adequate number of suture loops, adequate bites of tissue, following curve of needle important aspects Endarterectomy – can lead to aneurysmal degeneration because intima and media are removed

Etiology – physical stress Include hypertension, direct trauma, and compression and distraction forces with anastomosis across a joint Size mismatch can also be a factor, prosthetic grafts generally less compliant than native tissue Lateral forces generate stress preferentially on the native tissue Physical stresses increase as aneurysm size increases

Clinical presentation Generally asymptomatic, but are usually found on physical exam Can cause symptoms fullness, pain, pulsatility, and symptoms associated with local compression (weakness from compression of an adjacent nerve….) Clinical problems include rupture and bleeding into adjacent tissues, embolization from mural thrombus, thrombosis with distal ischemia, and venous congestion or thrombosis from compression of an adjacent vein Emergency operative intervention carries a higher morbidity and mortality Median time to indentification is 6 years, earlier manifestations should prompt an investigation into an infectious etiology including high resolution ct angio and esr rate

Femoral artery anastomosis Most prevalent site of anastomotic pseudoaneurysms Most cases are diagnosed as an asymptomatic pulsatile mass in up to 44% of cases; less than 10% require surgical intervention These should be monitored until they have a significant growth rate or the size is 2 to 2.5cm These should never be catheterized Can be monitored by ultrasound study, both sides should be investigated Endoluminal repair not an option as this is over a hip joint

Abdominal aorta anastomosis More common with aneurysmal pathology vs. occlusive disease, occur in 2 to 5% of patients with aortic grafts Imaging study should be performed every 5 to 10 years Patients may present with back or abdominal pain, also rupture with hemorrhage, thrombosis or embolism, and less commonly erosion into an adjacent structure such as bowel or vena cava Indications for intervention Symptomatic aneurysm Patient presenting with complications of anastomotic aneurysm Diameter greater than twice the diameter of the graft or more than 4 cm Also presence of a saccular rather than a fusiform aneurysm Retroperitoneal approach in preferrable providing better exposure for suprarenal/supraceliac control In noninfected cases endoluminal repair should be considered

Iliac artery anastomosis Can erode into small bowel or colon, not duodenum like the aorta Compression of iliac vein can lead to lower extremity swelling or DVT, also desmoplastic reaction around the anastomosis can lead ureteral obstruction and hyrdronephrosis Indication for repair include presence of symptoms, presence of complication, aneurysmal size 2.5 to 3 cm Iliac artery anastomotic aneurysms most suitable to endoluminal repair Need low probability of infectious cause Aneurysm does not need to be debulked No contraindication to internal iliac artery coil embolization Can be used for acute rupture depending on surgeon experience

Carotid artery pseudoaneurysms Incidence is rare 0.6% Due to technical problems, use of poor quality vein for patch, very bulbous reconstruction of the arteriotomy or infective process for prosthetic patch Can present as painful pulsatile cervical mass, also TIA’s Workup by ultrasound and CT angio, regular angiography not helpful Even small asymptomatic pseudoaneurysms should be fixed as they may degenerate and produce small thrombus and embolic material Author recommends bypass around aneurysm and endoluminal repair is contraindicated due to significant debris in lumen