Predictors of major amputation despite patent bypass grafts

• Published in: Journal of vascular surgery 2016-05, Vol.63 (5), p.1279-1288
• Main Authors: Smith, Ann D., MD, MPH, Hawkins, Alexander T., MD, MPH, Schaumeier, Maria J., MD, de Vos, Marit S., BS, Conte, Michael S., MD, Nguyen, Louis L., MD, MBA, MPH
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Amputation; Chi-Square Distribution; Comorbidity; Critical Illness; Disease Progression; Double-Blind Method; Female; Humans; Ischemia - diagnostic imaging; Ischemia - physiopathology; Ischemia - surgery; Limb Salvage; Lower Extremity - blood supply; Male; Middle Aged; Multivariate Analysis; Nutritional Status; Peripheral Arterial Disease - diagnostic imaging; Peripheral Arterial Disease - physiopathology; Peripheral Arterial Disease - surgery; Proportional Hazards Models; Prospective Studies; Quality of Life; Reoperation; Risk Assessment; Risk Factors; Surgery; Time Factors; Treatment Outcome; Vascular Grafting - adverse effects; Vascular Grafting - methods; Vascular Patency; Veins - diagnostic imaging; Veins - physiopathology; Veins - transplantation
• ISSN: 0741-5214; 1097-6809
• DOI: 10.1016/j.jvs.2015.10.101

Objective Despite patent vein bypass grafts, some patients with critical limb ischemia (CLI) receive major amputations. We analyzed the predictive factors leading to major amputation in the presence of patent lower extremity bypass (LEB) grafts. Methods Data from the Project of Ex-Vivo vein graft Engineering via Transfection III (PREVENT III), a large prospective randomized trial of 1404 patients who underwent LEB with vein graft for CLI, were queried for outcomes. The primary outcome was major amputation with patent (PMA) LEB compared with patients with patent LEB who achieved limb salvage (PLS). The population excluded those who received amputation for occluded grafts. A Cox proportional hazard model identified independent predictors. Results Of 1404 LEB patients, 162 (11.5%) had major amputation: 89 (6.3%) with patent and 73 (5.2%) with occluded LEB. For PMA, 21 of 89 (23.6%) developed critical stenosis and 11 of 21 (52.4%) were revised. For PLS, 460 of 1242 (37.0%) developed critical stenosis and 351 of 460 (76.3%) were revised. Predictive patient factors included having preoperative gangrene (vs rest pain; hazard ratio [HR], 3.504; 95% confidence interval [CI], 1.533-8.007; P  = .0029), diabetes (HR, 1.800; 95% CI, 1.006-3.219; P  = .0477), black (vs white) race (HR, 1.779; 95% CI, 1.051-3.011; P  = .0321), baseline creatinine clearance 65 mL/min; HR, 1.759; 95% CI, 1.016-3.048; P  = .0439), prior history of coronary artery bypass grafting (HR, 1.702; 95% CI, 1.080-2.683; P  = .0221), and lower baseline activity quality of life score (HR, 1.401; 95% CI, 1.105-1.778; P  = .0054). Postoperative wound factors included gangrenous changes (HR, 5.830; 95% CI, 1.647-20.635; P  = .0063), surgical wound necrosis (HR, 5.319; 95% CI, 1.478-19.146; P  = .0105), deep (vs superficial) wound infection (HR, 3.815; 95% CI, 1.220-11.927; P  = .0213), and wound healing abnormally (HR, 3.754; 95% CI, 1.061-13.278; P  = .0402). Associated postoperative consequences leading to PMA included having recurrent CLI symptoms (HR, 2.915; 95% CI, 1.816-4.681; P  < .0001), a severe (vs mild) adverse event (HR, 2.751; 95% CI, 1.391-5.443; P  = .0036), fewer percutaneous revisions (HR, 2.425; 95% CI, 1.573-3.740; P  < .0001), discharge on low-molecular-weight heparin (HR, 2.087; 95% CI, 1.309-3.326; P  = .0020), and decreasing days to critical stenosis/occlusion/revision/amputation (HR, 1.010; 95% CI, 1.007-1.012; P  < .0001). Conclusions Whereas a patent vein graft i