The use of intravascular ultrasound imaging to improve use of inferior vena cava filters in a high-risk bariatric population

ObjectivePulmonary embolism is the leading cause of death after gastric bypass procedures for obesity, approximating 0.5% to 4%. All bariatric patients, but especially the super-obese, which have a body mass index (BMI) >50 kg/m2, are at significant risk for postoperative venous thromboembolism (VTE). Visualization and weight limitations of fluoroscopy tables exclude most bariatric and all super-obese patients from inferior vena cava (IVC) filter placement using fluoroscopy. Intravascular ultrasound (IVUS)-guided IVC filter placement is the only modality that allows these high-risk patients to have an IVC filter placed.MethodsHospital and outpatient records of the 494 patients who underwent gastric bypass procedures from January 1, 2004, to May 31, 2006, were reviewed. All patients who had concurrent IVC filter placement with the use of IVUS guidance were selected. Comorbidities, outcomes, and complications were recorded.ResultsWe identified 27 patients with mean BMI of 70 ± 3 kg/m2; of these, 25 were super-obese (BMI >50 kg/m2). Procedures included five laparoscopic and 22 open gastric bypass operations. All patients underwent concurrent IVC filter placement using IVUS guidance. In addition to super-obesity, indications for IVC filter placement included history of VTE (n = 4), known hypercoagulable state (n = 2), and profound immobility (n = 21). Mean follow up was 293 ± 40 days. Technical success rate was 96.3%. There were no catheter site complications. In one surviving patient, a nonfatal pulmonary embolism was detected by computed tomography 2 months postoperatively. Two patients died, and autopsy excluded VTE as the cause of death in both.ConclusionThis study suggests efficacy of IVUS-guided IVC filter placement in preventing mortality from pulmonary embolism in high-risk bariatric patients, including the super-obese. IVUS-guided IVC filter placement can be safely performed with an excellent success rate in all bariatric patients, including the super-obese, who otherwise would not be candidates for IVC filter placement due to the limitations imposed by their large body habitus

His-384 allotypic variant of factor H associated with age-related macular degeneration has different heparin binding properties from the non-disease-associated form.

A polymorphism in complement factor H has recently been associated with age-related macular degeneration (AMD), the leading cause of blindness in the elderly. A histidine rather than a tyrosine at residue position 384 in the mature protein increases the risk of AMD. Here, using a recombinant construct, we show that amino acid 384 is adjacent to a heparin-binding site in CCP7 of factor H and demonstrate that the allotypic variants differentially recognize heparin. This functional alteration may affect binding of factor H to polyanionic patterns on host surfaces, potentially influencing complement activation, immune complex clearance, and inflammation in the macula of AMD patients

Complement factor H: using atomic resolution structure to illuminate disease mechanisms.

Complement Factor H has recently come to the fore with variant forms implicated in a range of serious disease states. This review aims to bring together recent data concerning the structure and biological activity of this molecule to highlight the way in which a molecular understanding of function may open novel therapeutic possibilities. In particular we examine the evidence for and against the hypothesis that sequence variations in factor H may predispose to disease if they perturb its ability to recognise and respond appropriately to polyanionic carbohydrates on host surfaces that require protection from complement-mediated damage