Ortel, Thomas L.

Abstract Abstract 2305 Background. Recurrent venous thromboembolism (VTE) occurs in ∼30% of patients with spontaneous VTE after completion of a standard course of anticoagulant therapy. D-dimer levels and selected clinical parameters have been used to identify patients at low risk for recurrent VTE, who may safely discontinue antithrombotic therapy. We have used gene expression profiles to distinguish patients with a single VTE from patients with recurrent VTE. The purpose of this study was to extend this initial report and identify unique gene expression patterns from whole blood that correlate with different risk profiles for VTE recurrence. Methods. Patients with ≥1 prior VTE, with the first event occurring at age 18 years or older and >3 months from the most recent event were recruited for this study. Patients were allocated into 4 groups: (1) ‘low-risk’ patients had sustained ≥1 provoked VTE; (2) ‘moderate-risk’ patients had sustained 1 unprovoked VTE (with or without provoked VTE); (3) ‘high-risk’ patients had sustained ≥2 unprovoked VTE and had no evidence for antiphospholipid antibodies; and (4) antiphospholipid syndrome (APS) patients met established consensus criteria for APS. A similar number of individuals with no prior history of VTE were enrolled as a control population. Citrated plasma, serum and PAXgene RNA tubes were collected, processed and stored at −80°C until shipped to the CDC for analysis. Antiphospholipid testing was performed on all participants to confirm correct group distribution. Total RNA was isolated from whole blood drawn into PAXgene tubes. Following sample labeling and normalization, cRNA samples were hybridized to Illumina HT-12 Beadchips to assay whole genome gene expression with over 47,000 probes against human transcripts. Two hundred and twenty six unique samples passed initial quality control measures. Quality assessment of raw data was done using GenomeStudio. The raw data files were converted to a text file using the IlluminaExpression FileCreator in GenePattern and then log transformed, normalized and median-centered using Cluster. Both unsupervised (hierarchical clustering using Cluster) and supervised analyses (SAM) were used to identify genes that were differentially expressed between the groups. GATHER was used to help understand the biological processes and gene ontology of the gene lists generated by Cluster and SAM. Results. A total of 226 participants were enrolled into the study. Characteristics of the patient groups are summarized in the Table. Demographically, the groups were similar except that patients in the high-risk group tended to be older and were more likely male. The number of events per patient, and the proportion on anticoagulant therapy, increased with the risk group. Antiphospholipid antibodies were detected in several patients in each of the 3 non-APS VTE patient groups, but in most cases this was a single test positive; antiphospholipid antibodies were present in the majority of patients with APS, typically with more than one test positive (37 of 45 with complete testing, 82%). Preliminary analysis of the gene expression profiles using an unsupervised clustering by gene on the high-risk and low-risk groups identified multiple genes that distinguished the two groups, including 18 immune response genes identified by GATHER. These two patient groups were also distinguished by SAM analysis, and multiple genes in the MAPK signaling pathway that separated the two groups were identified by the KEGG pathways in GATHER. Additional analyses are being performed on all of the groups. Conclusions. Whole blood gene expression profiling can be used to develop profiles that distinguish patients with VTE who differ based on their risk of recurrent events. Individual genes identified in these profiles may provide biological insights into the molecular basis for recurrent VTE. Disclosures: Heit: Daiichi Sankyo: Honoraria; Ortho-McNeil Janssen: Honoraria; Covidien: Honoraria. Manco-Johnson:Octapharma AG: Consultancy; Bayer: Research Funding.

Abstract Abstract 4219 Background: Clinical characteristics associated with abdominal vein thrombosis (including hepatic, portal, and mesenteric veins; renal veins; and inferior vena cava [IVC]) overlap with characteristics associated with deep vein thrombosis (DVT) in the legs and pulmonary embolism (PE) but also possess unique attributes. These characteristics may differ between adult and pediatric patient groups. Methods: Using a standardized data-collection form, demographic and baseline characteristics were prospectively collected from consecutive consenting patients enrolled within one of seven Thrombosis and Hemostasis Centers over a seven-year period, August 2003 to June 2010. Patients with intra-abdominal venous thrombosis (defined as abdominal and renal veins, and IVC) were divided into pediatric (age <18 years) and adult (age ≥18 years) groups and compared to patients in the same age ranges with lower extremity DVT and/or PE. RESULTS: As of June 2010, the Patient Registry contained a total of 3105 patients with venous thromboembolism (VTE). A total of 270 patients had intra-abdominal thrombosis (9%) compared to 2276 with lower extremity DVT and/or PE (73%). Of the intra-abdominal clots, pediatric patients were more likely to have IVC thrombus (22 of 42; 52%) than adults (38 of 228; 17%; p<0.0001); conversely, pediatric patients were less likely to have hepatic, portal, and mesenteric thrombosis (n=25; 60%) than adults (n=195; 86%, p<.0001). For adult patients, proportionately more women had abdominal thrombosis (157 of 228; 68.9%) than DVT/PE (1306 of 2140; 61%; p=0.02); in contrast, comparable numbers of female pediatric patients had abdominal thrombosis (20 of 42; 47.6%) and DVT/PE (68 of 136; 50%). The mean age for patients having abdominal thrombosis was lower than patients having DVT/PE for both adults (38.3 vs 43.0 yrs; p<0.0001) and pediatric patients (9.0 vs 11.9 yrs; p=0.014). Similarly, the mean body mass index was lower for patients having abdominal thrombosis than patients having DVT/PE for both adults (28.1 vs 30.8; p<0.0001) and pediatric patients (21.5 vs. 24.7; p=0.05). There were no relationships with race, ethnicity, or inherited thrombophilic disorders. In adults, autoimmune conditions (21.9 vs 13.6; p=0.0007) and recent surgery (14.0 vs 9.2; p=0.02) were more common in patients with abdominal thrombosis, whereas, hyperlipidemia was more frequent in patients with DVT/PE (8.3 vs 13.2; p=0.04). None of these relationships were seen in the pediatric patients, but trauma was more frequently seen in pediatric patients with DVT/PE than abdominal thrombosis. Sixty-one adult (26.8%) and 6 pediatric patients (14.3%) had another VTE elsewhere, with most occurring after the initial event (21 DVT and 7 PE). Similar proportions of adult and pediatric patients had arterial thromboembolic events for both abdominal thrombosis and DVT/PE. CONCLUSIONS: Adult patients with abdominal thrombosis are more likely female, have hepatic, portal and/or mesenteric vein thrombosis, and common co-morbid conditions include recent surgery and autoimmune disorders. Pediatric patients are evenly divided between male and female, more commonly have IVC thrombosis, and co-morbid conditions include recent trauma. Both adult and pediatric patients with abdominal thrombosis tend to be younger and have a lower BMI than patients with DVT and/or PE. We also found a high rate of concurrent thrombosis in both adult and pediatric patients with abdominal thrombosis. In summary, patients with abdominal thrombosis display different clinical characteristics when compared to those with DVT/PE, specifically in terms of gender, location of thrombosis, and associated co-morbidities. Some of these differences, such as higher rates of IVC thrombosis in pediatric patients with abdominal thrombosis, might be caused by variance between genetic and anatomic factors. Further studies are warranted to explain these differences. Disclosures: Kulkarni: Novo Nordisk: Membership on an entity's Board of Directors or advisory committees, Participate in clinical trials. Philipp:Baxter: Research Funding; Wyeth: Research Funding; Octapharma: Research Funding. Ortel:Sanofi-Aventis: Consultancy, Research Funding; Ortho-McNeil: Consultancy; GlaxoSmithKline: Research Funding; Eisai: Research Funding; Pfizer: Research Funding.

Abstract Abstract 2203 Background: Thrombotic thrombocytopenic purpura (TTP) is frequently characterized by severe ADAMTS13 deficiency, the cause of which is unknown. An important exception is ticlopidine-associated TTP (tc-TTP), the most common drug-induced TTP syndrome. In 1998, a possible association of TTP with ticlopidine was reported. In 1999, two additional series reported this association. In 2000, a fourth study reported severe A DAMTS13 deficiency among six of seven tc-TTP persons- suggesting a causal pathway. All of these reports were from the United States. Recently, we reported characteristics of 186 acquired idiopathic (ai)- TTP patients in Japan with severe ADAMTS13 deficiency, noting that clinical and laboratory findings for ai-TTP patients in Japan differed from those for cohorts of ai-TTP patients in Europe and North America- raising concern that TTP findings vary by region of the world. (PLOS One 2011) We now on report clinical and laboratory characteristics of a cohort of TTP patients from Japan with tc-TTP, and compare these findings to three cohorts of tc-TTP in the United States and one cohort of ai-TTP patients from Japan. Methods: We queried a database of thrombotic microangiopathy patients identified from a national TTP referral laboratory in Japan of cases identified between 1998 and 2008. Severe ADAMTS13 deficiency was characterized by activity levels < 5%. All tc-TTP patients and 186 of 911 ai-TTP patients in the database had severe ADAMTS13 deficiency and first onset of TTP. Comparisons were made to tc-TTP patients reported previously from the United States. Results: Characteristics of ai- TTP with severe ADAMTS13 deficiency in Japan and tc-TTP in Japan and US Conclusions: These data from Japan validate insights about tc-TTP initially proposed in 1998, 1999, and 2000 in the United States. Ticlopidine is a likely cause of TTP, the mechanism is via a cross-reactive antibody to ADAMTS13:AC resulting in formation of an ADAMTS13:INH, and therapeutic plasma exchange is necessary for treatment. Disclosures: Ortel: Eisai: Research Funding; Glaxo SmithKline: Research Funding; Pfizer: Research Funding; Instrumentation Laboratory, Inc: Consultancy, Research Funding; Boehringer Ingelheim: Consultancy. Fujimura:Baxter BioScience: Membership on an entity's Board of Directors or advisory committees; Alexion Pharma: Membership on an entity's Board of Directors or advisory committees.