Chapter review: anastomotic aneurysms

1. Chapter review: anastomotic aneurysms

2. 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

3. 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’

4. 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

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

6. 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

7. 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

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

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. 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