European Venous Forum Abstracts Eleventh Meeting of the European Venous Forum: Antwerp, Belgium, 24–26 June 2010 Thursday 24 June 2010 Presentations from the American Venous Forum Paper A1 Post-thrombotic vein wall remodelling: preliminary findings K Deatrick, N Baker, S DeRoo, M A Elfline, V Sood, S Stabler, S A Blackburn, C E Luke, T W Wakefield and P K Henke University of Michigan, Ann Arbor, MI, USA Background: Post-thrombotic syndrome (PTS) is character- ized by a fibrotic vein injury following deep vein throm- bosis (DVT), resulting in a less compliant vein wall. We sought to quantify the change in vein wall thickness, and to determine if vein wall damage, defined as wall thickening, is worsened in patients who fail to resolve DVT by six months, and whether there were differences in blood or plasma levels of proteins associated with tissue remodelling. Methods: Patients presenting with suspected lower extremity DVT were evaluated. Ultrasound imaging of the lower extremity venous system was performed and blood was collected. Patients with DVT received repeat evaluation with blood draw and ultrasound imaging at six months. DVT resolution was assessed using ultra- sound examination. The thickness of the vein wall was quantified by ultrasound imaging in each segment affected by thrombus, and a contralateral, unaffected vein wall served as a control. mRNA was extracted from whole blood using the PAXgene system, and serum pro- teins were analysed using enzyme-linked immunosor- bent assay (ELISA). Analysis of variance or Student’s t-tests were used and a P , 0.05 was significant. Results: Thirty patients (10 patients with DVT resolution at six months, 10 patients with persistent thrombus and 10 healthy controls) were compared. Both resolving and non-resolving DVT were associated with 1.5–1.8-fold increased vein wall thickness at six months (n ¼ 10–12; P ¼ 0.008) as compared with non-affected vein wall seg- ments. However, the thickness of the affected segments was 1.4-fold greater in patients who had a total resolution of the DVT by six months than in patients who had per- sistent chronic thrombus six months after presentation (N ¼ 10–12; P ¼ 0.01). There was a 4–5-fold increased level of matrix metalloproteinase (MMP)-9 in all throm- bosed groups compared with controls (n ¼ ; P , 0.05), while Toll-like receptor-9 (TLR-9) expression was three- fold less than controls (n ¼ ; P , 0.05). There were no stat- istically significant differences in the levels of associated factors such as D-dimer, P-selectin or inflammatory and remodelling markers such as SLC or MMP-2 by ELISA. There were no significant differences in the gene expression of C-reactive protein, MMP-2, MMP-9 or TLR-4. Conclusion: This preliminary study suggests ongoing vein wall remodelling after DVT. At six months, the vein wall is markedly thickened, but this change is inde- pendent of thrombus resolution, and associated with elevated MMP-9 but not other inflammatory markers. This suggests that the vein wall damage is initiated early following thrombus formation and persists even in the presence of total resolution. Paper A2 Validation of the Caprini risk assessment model in plastic and reconstructive surgery patients C J Pannucci*, S Bailey † , C Fisher ‡ , J Clavijo-Alvarez ‡ , J Hamill § , K Hume § , T Wakefield*, J Rubin ‡ , E Wilkins* and R Hoxworth † *University of Michigan, Ann Arbor, MI; † University of Texas- Southwestern, Dallas, TX; ‡ University of Pittsburgh, Pittsburgh, PA; § American Society of Plastic Surgeons, Arlington Heights, IL, USA Background: In contrast to other surgical subspecialties, the plastic surgery literature demonstrates a paucity of research regarding the efficacy of chemoprophylaxis in venous thromboembolism (VTE) prevention. As a result, we created a consortium of three tertiary referral centres with demonstrated expertise in plastic and reconstructive surgery to perform a prospective cohort study with historic controls to examine the efficacy of low-molecular- weight heparin prophylaxis for VTE prevention in plastic surgery patients. Methods: A mid-term analysis of the study’s control group was conducted to evaluate the incidence of VTE when chemoprophylaxis is not provided and to validate the predictive ability of the Caprini Risk Assessment Model (RAM) for VTE. Medical record review for patients undergoing plastic surgery between March 2006 and June 2008 was conducted. All patients with Caprini scores ≥3 having surgery under general anaesthesia with post- operative hospital admission were included. Patients who received any form of chemoprophylaxis were excluded. Outcomes of interest included symptomatic deep vein thrombosis (DVT) or pulmonary embolism (PE) (confirmed with imaging) within the first 60 post- operative days. Results: At present, 634 patients meeting inclusion cri- teria have been identified. Mean Caprini score was 5.3. VTE occurred in 16 patients (2.52%; 8 DVT, 4 PE, 4 DVT + PE) with 25% of VTE occurring between post- operative day 30 and 60. When compared with those Phlebology 2010;25:296–311. DOI: 10.1258/phleb.2010.010a02