syndrome. The diagnosis of thrombophilia in patients with mechanical heart valve prostheses can explain the inefficiency of anticoagulation therapy, warfarin resistance, “floating” hemostasis markers and difficulties in adequate dose selection. doi:10.1016/j.thromres.2012.08.063 C0208 Prevention of venous thromboembolism in acutely ill medical patients with renal impairment: The fondair study Walter Ageno 1 , Nicoletta Riva 2 , Patrizia Noris 3 , Marcello Di Nisio 4 , Micaela La Regina 5 , Dimitriy Arioli 6 , Luigi Ria 7 , Valter Monzani 8 , Stefano Cuppini 9 , Enrico Lupia 10 , Matteo Giorgi Pierfranceschi 11 , Francesco Dentali 2 1 University of InsubriaClinical and Experimental Medicine - Varese, Italy; 2 University of Insubria - Varese, Italy; 3 Policlinico San Matteo - Pavia, Italy; 4 University of Chieti-Pescara, Italy; 5 Ospedale S.Andrea - La Spezia, Italy; 6 Arcispedale S. Maria Nuova - Reggio Emilia, Italy; 7 Ospedale Sacro Cuore di Gesù - Gallipoli, Italy; 8 IRCCS Ospedale Maggiore Policlinico - Milan, Italy; 9 Ospedale di Rovigo, Italy; 10 Ospedale S. Giovanni - Turin, Italy; 11 Ospedale di Piacenza, Italy Background: A number of studies have reported that about 40% of acutely ill medical patients have moderate or severe renal impairment. Because these patients have an increased risk of both venous thrombo- embolism (VTE) and bleeding, the clinical benefit of pharmacologic prophylaxis for VTE prevention is particularly uncertain. Commonly used anticoagulant drugs with predominant renal excretion may cause an excessive anticoagulant effect due to drug bioaccumulation. The use of lower doses of the anticoagulant agent is suggested by clinical guidelines, but limited evidences are available to support this strategy. A lower dose of fondaparinux (1.5 mg daily) was recently approved for the prevention of VTE in hospitalized patients with a creatinine clearance between 20 and 50 mL/min after the results of pharmacokinetic simulations. Methods: To assess the safety and efficacy of lower dose fondaparinux in acutely ill medical patients with renal impairment, we carried out a multicenter, investigator-initiated, prospective cohort study. Patients at risk for VTE with a creatinine clearance between 20 and 50 mL/min were treated with fondaparinux 1.5 mg qd for a minimum of 6 to a maximum of 15 days. Patients were followed up for 1 month after inclusion in the study. Primary outcome was the incidence of major bleeding during treatment and two days thereafter, secondary out- comes were clinically relevant non-major bleeding (CRNMB) during the same time frame, and symptomatic VTE during treatment. Results: We enrolled 206 patients with a mean age of 82 years old, mean creatinine clearance of 33 mL/min, and a mean Charlson co- morbidity index of 8.2. Nearly two thirds of patients were receiving concomitant antiplatelet therapy. One patient had major bleeding (0.49%, 95% CI 0.03-3.10), 8 had CRNMB (3.88%, 95% CI 1.81-7.78), and 3 developed symptomatic VTE (1.46%, 0.38-4.55). Twenty-three patients (11.17%, 7.36-16.48)died, 10 while on prophylaxis, 13 during follow-up. No independent predictors of bleeding were found at univariate analysis. Comment: The presence of moderate to severe renal impairment in addition to usual criteria for the selection of patients at increased risk for VTE identified a population of very elderly acutely ill medical patients, with a high co-morbity index and potentially at high risk for both VTE and bleeding complications. The recently approved lower prophylactic dose of fondaparinux appears relatively safe and effective in these patients. doi:10.1016/j.thromres.2012.08.064 C0302 Prognostic clinical prediction rules to identify low-risk pulmonary embolism: A systematic review and meta-analysis Alessandro Squizzato 1 , Marco P. Donadini 1 , Luca Galli 1 , Francesco Dentali 1 , Drahomir Aujesky 2 , Walter Ageno 1 1 University of InsubriaResearch Center on Thromboembolic Disorders and Antithrombotic Therapies, Department of Clinical Medicine, - Varese, Italy; 2 Bern University Hospital, Division of General Internal Medicine - Bern, Switzerland Background: Prognostic assessment is important for the manage- ment of patients with pulmonary embolism (PE). A number of CPRs have been proposed for stratifying PE mortality risk. Aim of this systematic review is to assess the performance of prognostic clinical prediction rules (CPRs) in identifying low-risk PE. Methods: MEDLINE and EMBASE databases were systematically searched until August 2011. Derivation and validation studies that assessed the performance of prognostic CPRs in predicting adverse events-risk in PE patients were included. Weighted mean proportion and 95% confidence intervals (CIs) of adverse events were then calculated and pooled using a fixed and a random-effects model. Statistical heterogeneity was evaluated through the use of I(2) statistics. Results: Of 1125 references in the original search, 33 relevant articles were included. Nine CPRs were assessed in 37 cohorts, for a total of 35,518 patients. Pulmonary Embolism Severity Index and prognostic Geneva CPR were investigated in 22 and 6 cohorts, respectively. Eleven (29.7%) cohorts were of high quality. Median follow-up was 30 days. In low-risk PE patients, pooled short-term mortality (within 14 days or less) was 0.7% (95% CI 0.3-1.1%, random-effects model; I 2 = 49.6%), 30-day mortality was 1.7% (95% CI 1.1-2.3%, random-effects model; I 2 = 82.4%), and 90-day mortality was 2.2% (95% CI 1.2-3.4%, random-effects model; I 2 =59.8%). in low risk PE patients according to PESI (class I and II), in- hospital mortality was 0.2% (95% CI 0–0.7) and non fatal recurrent venous thromboembolism and major bleeding was 0.6% (0.2-1.4). Comment: Prognostic CPRs efficiently identify PE patients at low risk of mortality. In particular, CPRs identify low risk PE patients better than markers of right ventricular dysfunction (echocardiography, elevated levels of BNP, NT-pro-BNP or troponins). CPRs should be implemented in the routine care of PE patients to drive appropriate management. doi:10.1016/j.thromres.2012.08.065 C0322 Factors associated with therapeutic strategies in patients with splanchnic vein thrombosis: Results of an international registry Nicoletta Riva 1 , Walter Ageno 1 , Sam Schulman 2 , Soo-Mee Bang 3 , Maria Teresa Sartori 4 , Elvira Grandone 5 , Jan Beyer 6 , Giovanni Barillari 7 , Dario Di Minno 8 , Rita Duce 9 , Alessandra Malato 10 , Rita Santoro 11 , Daniela Poli 12 , Peter Verhamme 13 , Ida Martinelli 14 , Pieter Kamphuisen 15 , Adriano Alatri 16 , Doyeun Oh 17 , Elbio D'Amico 18 , Francesco Dentali 19 1 Department of Clinical MedicineInsubria University - Varese, Italy; 2 McMaster University - Hamilton, ON, Canada; 3 Seoul National University - Seoul, Korea; 4 University of Padua - Padua, Italy; 5 IRCCS Casa Sollievo Della Sofferenza - S. Giovanni Rotondo, Italy; 6 Dresden University Clinic - Dresden, Germany; 7 Ospedale di Udine - Udine, Italy; 8 University of Naples - Naples, Italy; 9 Galliera Hospital - Genoa, Italy; 10 University of Palermo - Palermo, Italy; 11 Azienda Ospedaliera Pugliese- Ciaccio - Catanzaro, Italy; 12 Careggi Hospital - Florence, Italy; 13 Leuven University - Leuven, Belgium; 14 Ospedale Maggiore Policlinico - Milan, Italy; 15 University of Groningen - Groningen, The Netherlands; 16 Ospedale di Cremona - Cremona, Italy; 17 Pochon CHA University - Seoul, Korea; Abstracts / Thrombosis Research 130 (2012) S100–S202 S125