Vascular Graft Failure of Leg Arterial Bypasses - A Review - Vascular Graft Failure of Leg Arterial Bypasses - A Review - Open Access Pub

DOI10.14302/issn.2329-9487.jhc-14-404 A major problem facing the vascular surgeon is graft failure. Patients are often more symptomatic after graft failure than they were before the bypass procedure 1. Vein graft failure can be divided into three phases, depending on the timing of failure: early (<30 days), intermediate (30 days–2 years) and late (>2 years) 1, 2. Acute graft failures (within 48 hrs.) are usually secondary to technical errors such as poor anastomosis, poor inflow or outflow or a retained unlysed valve cusps 1, 2. Graft failure occurring between 2 days and 12 weeks after surgery is usually secondary to increased graft thromboreactivity 1, 3, 4. All grafts or reconstructions involve thromboreactivity but it varies in intensity and duration and is governed by both host factors (coagulability and blood flow), and by graft factors (surface thrombogenicity and compliance) 3. The thrombotic threshold velocity is required to maintain graft patency and thrombosis and closure of the graft occur for velocities below a given level for any graft material 3. The cause of intermediate vein graft failure is intimal hyperplasia 1, 5. Anastomotic intimal hyperplasia is commonly greater at the downstream or at the outflow anastomosis 6. Late vein graft failure is generally caused by dyslipidemia and the progression of atherosclerosis, compromising either inflow or outflow vessels 1, 5. Structural failures are rare in modern day fabric prostheses 7. Dilatation of the graft results in bleeding though intercises of graft, breakdown of fiber resulting in holes and tears, mural thrombus deposition which finally leads to graft occlusion, and can form anastomotic aneurysms 3, 8. Knitted fabrics have much more stretch because of their looped structure even though woven grafts with interlocking yarns have little or no inherentstretch 9. Dilation is caused by the loops straightening in the line of greatest stress 3. Patients with these grafts require life time follow-up 3. Advanced degeneration requires replacement of the graft 3, 10. A partial or complete separation of the prosthetic graft from the host artery can lead to an anastomotic false aneurysm 11. False aneurysms are most commonly found at the common femoral artery 3, 11. Atherosclerotic degenerative changes in the host artery wall are the cause of the tear 3, 12. Other factors leading to the formation of false aneurysm are compliance mismatch between the host artery and the graft, incorrect suturing technique, infection and tension on the suture line 3. Rupture, thrombosis, and embolism are some of the