Proportion Of Venous Thromboembolism Research Articles

Reduction in Prevalence of Thrombotic Events in Sickle Cell Disease after Allogeneic Hematopoietic Stem Cell Transplantation

Background: Venous thromboembolism (VTE) is a recognized complication of sickle cell disease (SCD). SCD confers a life-time risk of development of VTE, with a cumulative incidence of 11.3% by age of 40 years based on Cooperative group studies. Patients with SCD and VTE have a higher mortality rate (HR, 2.32; 95% CI, 1.20-4.46) compared to those without VTE (Naik et al, Am J Med. 2013;126(5):443-449). However, it remains unclear if this thrombotic pre-disposition improves after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: This is a retrospective single institution cohort study of SCD patients with history of VTE and/or cerebrovascular accident (CVA) who underwent allo-HSCT for indications of CVA, recurrent acute chest, or organ dysfunction related to SCD. Inclusion criteria included SCD genotype, VTE of any location, or CVA confirmed on ultrasound, V/Q scan, or CT/MRI angiography/venography. The number and proportion of VTE and CVA events were recorded before and after allo-HSCT. Patients who had VTE events prior to transplant did not have their anticoagulation or aspirin continued post-transplant. Statistical and clinically significant differences were identified using non-parametric analysis using McNemar's method with exact probability and binomial distribution. Multivariate analysis was done to identify potential explanatory variables within results. Results: 26 patients with SCD met inclusion criteria, all had HbSS genotype. 23 patients (88%) underwent HLA-haploidentical bone marrow transplant (haplo-BMT) with reduced intensity conditioning and 3 (12%) patients had myeloablative matched sibling donor transplants (MSD). Graft-versus-Host Disease (GVHD) prophylaxis included posttransplant cyclophosphamide/sirolimus/mycophenolate and cyclosporine/methotrexate in haplo-BMT and MSD, respectively. All patients had standard infection prophylaxis. The median age was 25 years (range: 8-54) at transplant and 17 patients were male (62%). 18 patients were taking hydroxyurea and 9 were on chronic transfusion therapy. Two patients had a second transplant for prior graft failure following haplo-BMT, all achieved 100% donor chimerism on days 30 and 100. Median follow up for the cohort was 74.5 (range:10-212) months total and 28.5 (range: 9-111) post allo-HSCT. Prior to allo-HSCT, 10 patients developed 7 deep vein thrombosis (DVT) and 3 pulmonary emboli. Seven of these (70%) were unprovoked events. 11 patients (40%) had ischemic CVA. Post-transplant, there were two provoked DVTs and one embolic stroke events in three patients, of which two had a history of provoked VTE (Figure). One DVT and the embolic stroke were associated with venous catheter use in a patient with PFO (patent foramen ovale). Only one patient had grade two acute GVHD after development of DVT. All events occurred within 30 days post transplantation and during acute hospitalization. No further VTE occurred after 3 months of anticoagulation in all patients. There was an absolute difference of 25% [95% CI=4.87- 26.9, p=0.015] in the prevalence of VTE events before and after allo-HSCT. In addition, there was an absolute 38.5% [95% CI=10.63-45.96, p=0.006] difference in the number of ischemic CVA before and after allo-HSCT. GVHD status, infection rates, age, history of pulmonary hypertension, and gender did not reach significance in explaining variation in results on logistic multivariate analysis (p > 0.05). Conclusion : In patients with SCD with a history of thrombosis, there is an observed reduction in prevalence of VTE and stroke events post transplantation. Allogeneic stem cell transplantation may attenuate the ongoing activation of the coagulation cascade and hypercoagulable state in SCD. This needs to be validated in a larger prospective cohort study. Disclosures Green: Scripps: Honoraria, Other: travel; North American Thrombosis: Honoraria; CSL: Research Funding; Baxter,: Research Funding; Baxalta: Research Funding; Shire US Inc: Other: clinical trial support. Dholaria:bms: Research Funding; Poseida: Research Funding; Angiocrine: Research Funding; Takeda: Research Funding; J&J: Research Funding.

Survey of related factors of maternal venous thromboembolism in nine hospitals of China

Objective: To investigate and analyze disease status and risk factors of venous thromboembolism (VTE) during pregnancy and puerperium in our country. Methods: Clinical datas were collected from 575 patients diagnosed with VTE during pregnancy and puerperium and hospitalized in nine medical institutions in our country from January 1, 2015 to November 30, 2019, and retrospectively analyzed it's disease status and risk factors. Results: (1) The proportion of VTE in pregnancy and puerperium was 50.6% (291/575) and 49.4% (284/575), respectively. Four patients died, the mortality rate was 0.7% (4/575). The cause of death was pulmonary embolism. (2) The location of VTE during pregnancy and puerperium was mainly in the lower limb vascular (76.2%, 438/575), followed by pulmonary vessels (7.1%, 41/575). (3) In the risk factors of VTE, cesarean section accounted for 32.3% (186/575), maternal advance age accounted for 27.7% (159/575), braking or hospitalization during pregnancy accounted for 13.6% (78/575), other risk factors accounted for more than 5% were previous VTE, obesity, preterm birth, assistant reproductive technology conception and so on, pre-eclampsia and multiple pregnancy accounted for 4.9% (28/575) respectively. In addition, some patients with VTE did not have any of the above risk factors, and the incidence rate was as high as 23.1% (133/575). Conclusions: The occurrence of VTE during pregnancy and puerperium is related to multiple risk factors, and could lead to matemal death, It is very necessary to screen VTE risk factors for all pregnant women, to make corresponding prevention and control measures.

High incidence of venous thromboembolic events in anticoagulated severe COVID‐19 patients

BackgroundCoagulopathy is a common abnormality in patients with COVID‐19. However, the exact incidence of venous thromboembolic event is unknown in anticoagulated, severe COVID‐19 patients. ObjectivesSystematic assessment of venous thromboembolism (VTE) using complete duplex ultrasound (CDU) in anticoagulated COVID‐19 patients. Patients and methodsWe performed a retrospective study in 2 French intensive care units (ICU) where CDU is performed as a standard of care. A CDU from thigh to ankle at selected sites with Doppler waveforms and images was performed early during ICU stay in patients admitted with COVID‐19. Anticoagulation dose was left to the discretion of the treating physician based on the individual risk of thrombosis. Patients were classified as treated with prophylactic anticoagulation or therapeutic anticoagulation. Pulmonary embolism was systematically searched in patients with persistent hypoxemia or secondary deterioration. ResultsFrom March 19 to April 11, 2020, 26 consecutive patients with severe COVID‐19 were screened for VTE. Eight patients (31%) were treated with prophylactic anticoagulation, whereas 18 patients (69%) were treated with therapeutic anticoagulation. The overall rate of VTE in patients was 69%. The proportion of VTE was significantly higher in patients treated with prophylactic anticoagulation when compared with the other group (100% vs 56%, respectively, P = .03). Surprisingly, we found a high rate of thromboembolic events in COVID‐19 patients treated with therapeutic anticoagulation, with 56% of VTE and 6 pulmonary embolisms. ConclusionOur results suggest considering both systematic screening of VTE and early therapeutic anticoagulation in severe ICU COVID‐19 patients.

OC-089 Linked hospital and primary care database study of venous thromboembolism and associated mortality following general surgical procedures in england

Introduction Trends towards shortening hospital stay through day case surgery and enhanced recovery mean that postoperative venous thromboembolism (VTE) may increasingly occur following hospital discharge. However, population rates of postoperative VTE cannot be measured from hospital databases alone, as they do not capture information outside of the hospital setting. The National Institute for Health and Care Excellence has suggested the use of linked hospital and primary care data to gain a better understanding of rates of hospital care-related VTE, 1 however, data for surgical patients is lacking. Method Ninety-day in-hospital and post-discharge VTE and mortality were evaluated in twelve general surgical procedures performed from 1997 to 2012 using linked Clinical Practice Research Datalink (CPRD), Hospital Episodes Statistics (HES), Office of National Statistics (ONS) and National Cancer Intelligence Network (NCIN) databases. The proportion of VTE captured in each database and risk factors for VTE and mortality were evaluated. Results 168005 operations over fifteen years were evaluated. There were 981 (0.58%) VTE events recorded after 90 days postoperatively. Different datasets recorded variable rates of VTE. CPRD recorded 56.0% (549/981), HES recorded 66.3% (650/981) and ONS recorded 8.3% (81/981) of all recorded VTE. For VTE recorded in two databases, 28.3% (278/981) were in HES and CPRD and 2.1% (21/981) in HES and ONS. Overall VTE rate ranged between 0.08% (14/17554, 3.2/1000 patient years) following haemorrhoidectomy to 2.92% (61/2091, 118.3/1000 patient years) following oesophagogastrectomy. Predictors of VTE included emergency surgery (OR = 1.91), age (OR = 1.02), body mass index (OR = 1.03), previous VTE (OR = 8.07), length of stay (OR = 1.00) and cancer stages II (OR = 1.38), III (OR = 1.50) and IV (OR = 1.63). Major organ resections had the greatest odds of VTE. The frequency of in-hospital VTE ranged from 76.4 to 288.9/1000 person years, while post-discharge VTE ranged from 2.6 to 82.1/1000 patient years. Both in-hospital (OR = 2.07) and post-discharge (OR = 4.03) VTE independently predicted 90-day mortality (p Conclusion A large proportion of postoperative VTE were detected in the primary care setting. Evaluation of linked databases is a useful way of measuring postoperative VTE at population level. These resources identified substantial harm from post-discharge VTE following general surgical procedures. Disclosure of interest None Declared. Reference National Institute for Health and Care Excellence. Venous thromboembolism in patients admitted to hospital. Guideline No. 92, 2010

The increased risk of venous thromboembolism by advancing age cannot be attributed to the higher incidence of cancer in the elderly: the Tromsø study.

Whether the high incidence of venous thromboembolism (VTE) in the elderly can be attributed to cancer is not well studied. We assessed the impact of cancer on risk of VTE in young, middle-aged and elderly. 26,094 subjects without a history of cancer or VTE were recruited from the Tromsø study. Incident cancer (n = 2,290) and VTE (n = 531) were recorded from baseline (1994-1995) through December 31st, 2009. Cox regression with cancer as time-varying exposure was used to calculate hazard ratios with 95 % confidence intervals (CI). Overt cancer was associated with a fivefold (95 %CI 4.3, 6.7) increased risk of VTE, with an age-dependent gradient from 26-fold (95 %CI 12.1, 56.5) increased in the young, ninefold (95 % CI 6.6, 12.7) increased in the middle-aged, and threefold (95 % CI 2.5, 4.5) increased risk in the elderly. The population attributable risks were 14, 27 and 18 %, respectively. The relative risk of VTE by cancer were higher in young compared to elderly subjects, but the proportion of VTEs in the population due to cancer did not differ much across age groups. Our findings indicate that the increased risk of VTE by advancing age cannot be attributed to higher incidence of cancer in the elderly.

Proportion and prevention of venous thromboembolism among hospitalized patients with acute exacerbation of chronic obstructive pulmonary disease in Beijing

To explore the proportion and prevention status of venous thromboembolism (VTE) among hospitalized patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) in Beijing. Based on a multi-center retrospective study, a total of 636 hospitalized AECOPD patients from 17 class 2/3 hospitals in Beijing were examined from September 1, 2011 to March 31, 2012. They fulfilled one of the following criteria: respiratory failure type II, on invasive or non-invasive mechanical ventilation, hospitalization for pulmonary infection, bedridden duration ≥ 3 days and congestive heart failure. All investigators received standardized training and used a standardized questionnaire to collect data on VTE risk factors, the diagnosis of VTE and the utilization of VTE prophylaxis. According to Caprini score, they were categorized into 3 groups of lower risk (Caprini score ≤ 3), moderate risk (Caprini score 4-6) and high risk ( ≥ 7) to compare the intergroup differences in the VTE proportion and the utilization of VTE prophylaxis. A total of 636 patients were assessed. There were 416 males and 220 females with a mean (SD) age of 74.9 ± 9.3 years. Among them, 133 patients received lower extremity venous ultrasonic examination and 92 were diagnosed with deep venous thrombosis (DVT) including 2 patients with pulmonary thromboembolism (PTE). Thus the overall incidence of VTE was 14.5% (92/636) and increased with age (Ptrend = 0.044). The proportion of VTE in asymptomatic patients was higher in those symptomatic ones (21.1% vs 8.0%, P = 0.000). And it was the highest in high risk group, followed by lower risk and moderate risk groups at 17.9% (14/78), 16.0% (26/163) and 13.2% (52/395) respectively, There was no statistical significance (P = 0.450 for group difference, Ptrend = 0.946). Among 544 patients without VTE, only 19.1% (104/544) employed the pharmacologic and/or mechanical methods for preventing VTE. The prevention proportion gradually increased with rising Caprini score, i.e. 17.5%, 18.4% and 26.6% for lower, moderate and higher risk group respectively. There was no statistical significance (P = 0.266 for group difference, Ptrend = 0.201). The proportion of VTE is relatively higher. However, the preventive methods are significantly underutilized among hospitalized AECOPD patients in Beijing.

Postpartum Venous Thromboembolic Events Among Carriers of Factor V Leiden and/or Prothrombin Gene Variant: A Cohort Study and Updated Systematic Review. Is Prophylaxis Really Required?

AbstractAbstract 1142 BackgroundPregnancy is associated with a hypercoagulable state, with the highest risk of venous thromboembolism (VTE) occurring during the postpartum period. This risk is further increased by the presence of inherited thrombophilic states, including Factor V Leiden (FVL) or the prothrombin gene variant (PGV), such that many clinicians provide routine postpartum thromboprophylaxis for this group. Publications examining the absolute incidence of pregnancy associated VTE in carriers of FVL and PGV report a rate of only 0–1% over the combined antepartum and 6–12 week postpartum periods. However, given that at least 50% of pregnancy associated VTE occur postpartum, the daily risk of VTE may be sufficiently high to warrant thromboprophylaxis during this period. Objectives1.To determine the absolute rate of postpartum VTE among a prospectively enrolled cohort of FVL or PGV positive women.2.To determine the pooled proportion of postpartum VTE in this population through a systematic review of published prospective cohort studies. MethodsWe performed a substudy analysis of the prospective Ottawa and Kingston (OaK) birth cohort study, in which women presenting for routine antenatal care were followed throughout pregnancy until delivery. Genotyping for FVL and PGV by polymerase chain reaction was performed for all participants after completion of the postpartum period. 336 women who enrolled through the participating Ottawa hospitals and identified as FVL or PGV positive were eligible for the current analysis. Data relating to the occurrence of VTE during the 6-week post partum period were obtained for 201/336 women through medical record review or direct contact by a study investigator. The main outcome measure was the proportion of objectively confirmed VTE within 6 weeks of delivery among participants with heterozygous FVL or PGV.Eligible articles were identified through a comprehensive search of the MEDLINE database. Inclusion criteria included a) prospective cohort design of women completing pregnancy during the study period; b) assessment of all participants for FVL and/or PGV; c) observation of participants throughout the postpartum period; d) report of objectively confirmed VTE during the postpartum period. Studies limited to women with previous pregnancy complications or previous VTE were excluded. The pooled proportion of postpartum VTE was calculated from combination of reported postpartum VTE rates and the current study results. ResultsNo postpartum VTE occurred among the 188 participants heterozygous for FVL or PGV alone. The proportion of VTE among the population with isolated heterozygous FVL and/or PGV was 0% (95% CI 0 to 2.0). One postpartum event was documented in a heterozygous PGV carrier with coexisting protein C deficiency. No events were documented among 12 women with homozygous or compound heterozygous defects. Superficial vein thrombosis was diagnosed in two carriers of FVL.Ten publications examining the rate of postpartum VTE among FVL or PGV carriers were identified in the systematic review. (Table 1) The pooled proportion of postpartum VTE among those who did not receive postpartum prophylaxis was 0.6% (95% CI 0.2 to 1.3) for heterozygous carriers of FVL and 0% (95% CI 0 to 1.6) for PGV heterozygotes. ConclusionThe absolute risk of VTE among asymptomatic carriers of FVL or PGV appears sufficiently low to withhold postpartum prophylaxis.Table 1Pooled Proportions of Postpartum VTEStudyProportion Receiving ProphylaxisVTE Proportion: No prophylaxis (95% CI)VTE Proportion: Prophylaxis or unknown prophylaxis (95% CI)FVL - HeterozygousDizon-Townson 1997NR–0/13Lindqvist 19994/2632/2591/4Eichinger 1999None0/11–Murphy 2000NR–0/16Middledorp 20019/170/80/9Salomen 2004None0/23–Dizon-Townson 2005None0/134–Clark 2008NR–0/142Kjellberg 2010128/4723/3440/128Current Study14/1390/1250/14Pooled Proportion5/904 = 0.6% (0.2–1.3)1/326 = 0.3% (0.1–1.7)PGV - HeterozygousSalomen 2004None0/27–Silver 2010None0/156–Current Study*1/480/470/1Pooled Proportion0/230 = 0% (0–1.6)Insufficient data for pooled proportionFVL: factor V Leiden, PGV: prothrombin gene variant, NR: not reported.*Data regarding postpartum prophylaxis unavailable in one case. Disclosures:Ramsay:Heart and Stroke Foundation of Canada: Research Funding; Canadian Institutes of Health Research: Research Funding. Rodger:Canadian Institutes of Health Research: Research Funding; Heart and Stroke Foundation of Canada: Research Funding.

Aspirin or enoxaparin thromboprophylaxis for patients with newly diagnosed multiple myeloma treated with lenalidomide

AbstractLenalidomide plus dexamethasone is effective in the treatment of multiple myeloma (MM) but is associated with an increased risk of venous thromboembolism (VTE). This prospective, open-label, randomized substudy of a phase 3 trial compared the efficacy and safety of thromboprophylaxis with low-dose aspirin (ASA) or low-molecular-weight heparin (LMWH) in patients with newly diagnosed MM, treated with lenalidomide and low-dose dexamethasone induction and melphalan-prednisone-lenalidomide consolidation. Overall, 342 patients who did not have clinical indications or contraindications to antiplatelet or anticoagulant therapy were randomly assigned to receive ASA 100 mg/d (n = 176) or LMWH enoxaparin 40 mg/d (n = 166). The incidence of VTE was 2.27% in the ASA group and 1.20% in the LMWH group. Compared with LMWH, the absolute difference in the proportion of VTE was 1.07% (95% confidence interval, −1.69-3.83; P = .452) in the ASA group. Pulmonary embolism was observed in 1.70% of patients in the ASA group and none in the LMWH group. No arterial thrombosis, acute cardiovascular events, or sudden deaths were reported. No major hemorrhagic complications were reported. In previously untreated patients with MM receiving lenalidomide with a low thromboembolic risk, ASA could be an effective and less-expensive alternative to LMWH thromboprophylaxis. This study was registered at www.clinicaltrials.gov as #NCT00551928.

The Epidemiology of Venous Thromboembolism in the Elderly: a Population-Based Study.

Abstract 2980 Poster Board II-954 Background. There are few studies that examine incidence trends of venous thromboembolism (VTE) among the elderly, and moreover data on changes in the prevalence over time of VTE risk factors such as hospitalization are limited. Objectives. Using the Province of Québec's administrative health claims (“RAMQ”) and hospitalization (“MED ECHO”) databases, we determined among individuals 65 years of age and older the trend in annual VTE incidence over a ten-year period, and examined the prevalence of hospital vs. community acquired VTE over time. Methods. Using RAMQ medical service and prescription claims data, we identified a cohort of elderly persons with incident VTE between 1983 and 1994. All individuals 65 years of age and older between January 1, 1994 and December 31, 2004 with at least one medical service (i.e. physician) claim linked to a VTE ICD-9 code in conjunction with a prescription claim for an anticoagulant in the subsequent 60 days, and who had no prior VTE-coded claim between 1983 and 1994 were included in the cohort. The first (incident) VTE-coded claim (index claim) during the period between January 1, 1994 and December 31, 2004 defined entry into the cohort. Using Québec population census data, we determined annual VTE incidence estimates, adjusting for the population's age and sex distribution as per 1999 census data. An index VTE event that occurred during a hospitalization and up to 90 days following hospital discharge was defined as hospital-acquired VTE, otherwise it was considered to be community-acquired. Results. A total of 27 758 persons were included in our cohort. The age and sex adjusted annual VTE incidence among individuals 65 years of age and older was 2.1, 2.7, and 2.8 per 1000 population in 1994, 1999 and 2004, respectively (p trend < 0.001 (across years)). The incidence rates increased with age and were slightly higher in men than women. Overall, 35% of VTE events were hospital-acquired (n=9598) and 65% occurred in the community (n=18160). There was a significant trend over time of an increase in the proportion of VTE associated with hospitalization with 32% of VTE being hospital acquired in 1994 and 39% in 2004. Conclusion. In a general population of individuals 65 years of age and older, VTE is a common problem, and its overall annual incidence has increased over time. Our results suggest that hospital admission and recent hospitalization are increasingly important risk factors for VTE occurrence in this population, and that efforts are needed to improve and optimize VTE preventative strategies in the hospitalized elderly. Disclosures: No relevant conflicts of interest to declare.

Venous Thromboembolism (VTE) in Patients (pts.) with Monoclonal Gammopathy of Undetermined Significance (MGUS)

Introduction: MGUS is considered to be a pre-malignant condition, and previous studies have reported VTE as a marker for a subsequent malignancy. We conducted a retrospective study to evaluate the incidence of VTE among MGUS patients (pts) and to correlate this incidence with different risk groups for developing malignancy in MGUS pts.Methods: The complete medical records of all MGUS pts at Cleveland Clinic Cancer Center at Fairview hospital from Jun/2005–Jun/2008 were retrospectively reviewed. Of 237 pts diagnosed with MGUS, 112 pts (65 males, 47 females) were eligible for our study. These pts were divided into 2 risk groups: low risk (LR)/low-intermediate risk (LIR) group (78 pts.) and high intermediate risk (HIR)/high risk (HR) group (34 pts) based on the Risk Stratification Model using three adverse risk factors; serum M-protein level ≥ 3 gm/dL, non-IgG MGUS, and an abnormal kappa/lambda free light chain ratio. Only pts with ≥ 12 months follow up were included. Exclusion criteria included a personal history of inherited thrombophilia, previous episode of VTE or anticoagulant treatment, thrombocytosis, malignancy, and renal impairment. Risk factors (RF) for VTE were identified in each pt and categorized into four groups: no RF, 0; one RF, 1; two RF, 2; and > 2 RF, >2. RF included > 48 hours of immobilization, surgery in the past 3 months, current hospitalization at the time of VTE occurrence, oral contraceptive use, and congestive heart failure.Objectives:To compare the proportion of pts with MGUS who developed VTE to the proportion of pts in the general population who developed VTE.To compare VTE incidence between the two risk groups.Results: During the study period, 9 pts with MGUS experienced VTE. In the general population, the incidence of VTE is 117/100,000 persons/year (from literature). Therefore, the proportion of pts in the general population over 3 years was 117/100000 × 3 =0.0035. The proportion of VTE in MGUS pts, adjusted for 3 years, of 0.080 is significantly higher than that for the general population (p<0.001). Comparison of VTE incidence between the two risk groups, while adjusting for the number of risk factors, showed no difference (Cox Proportional Model, p=0.38). There is no significant difference in the risk of VTE among different levels of risk factors (p=0.96). The Kaplan-Meier estimates of the proportions of pts free of VTE at 24 months are 0.96 and 0.93 for the LR/LIR and HIR/HR groups, respectively.Conclusions: MGUS is associated with a significantly higher rate of VTE compared to the general population. Despite many studies indicating VTE as a marker for subsequent malignancy, we did not find a difference in the incidence of VTE among the various risk factor groups. Any suggestive signs of VTE in pts with MGUS should be promptly evaluated and treatment initiated as soon as possible. Since the number of pts is small and the period of follow-up relatively short, a prospective cohort study is needed to verify our results.Table?: Comparison of event rate:VTEPop-valueTotal number of ptsRisk stratification model (pts)Groups (pts)VTE Proportion112LR (38)LR/LIR (78)(5)LIR (40)0.0800.0035<0.001HIR (26)HIR/HR (34)(4)HR (8)Note: Po is the VTE proportion for the general population over a 3-year time period.

Sickle cell trait and the risk of venous thromboembolism among blacks

AbstractPeople with sickle cell disease have a chronically activated coagulation system and display hemostatic perturbations, but it is unknown whether they experience an increased risk of venous thromboembolism. We conducted a case–control study of venous thromboembolism that included 515 hospitalized black patients and 555 black controls obtained from medical clinics. All subjects were assayed for hemoglobin S and hemoglobin C genotypes. The prevalence of the S allele was 0.070 and 0.032 for case patients and controls, respectively (P < .001). The odds that a patient had sickle cell trait were approximately twice that of a control, indicating that the risk of venous thromboembolism is increased approximately 2-fold among blacks with sickle cell trait compared with those with the wild-type genotype (odds ratio = 1.8 with 95% confidence interval, 1.2-2.9). The odds ratio for pulmonary embolism and sickle cell trait was higher, 3.9 (2.2-6.9). The prevalence of sickle cell disease was also increased among case patients compared with controls. We conclude that sickle cell trait is a risk factor for venous thromboembolism and that the proportion of venous thromboembolism among blacks attributable to the mutation is approximately 7%.

Clear cell endometrial cancer patients have an increased risk of venous thrombotic events

5597 Objective: To document the rate of clinically significant venous thromboembolism (VTE) in patients with clear cell carcinoma of the endometrium (CCC-E). Methods: Institutional review board (IRB) permission was obtained for retrospective record review. The pathology database at our institution located cases of CCCs over the time period 1994–2004. Controls with high grade endometrial cancers were matched for stage, age and date of diagnosis. All patients underwent surgical staging with gynecologic oncology staff surgeons and all patients received VTE prophylaxis peri-operatively. Records were reviewed and data were collected regarding patient age, tumor stage, body mass index, surgical procedure, adjuvant therapy, survival, and presence of VTE. All pathology was reviewed at the MGH. Results: Thirty-nine cases of CCC-E were identified. Complete clinical data were available for 29 cases. Age ranged from 38–85 (mean 64.6) years. 35% of patients had stage I tumors, 10% stage II, 27.5% stage III, and 27.5% had stage IV tumors. 58 age and stage matched controls were selected. The majority were grade 3 endometrioid cancers (50%) with the remainder being serous (35%), mixed histology (7%), carcinosarcoma (5%), and undifferentiated carcinoma (3%). The majority of the control patients had a higher BMI than the case patients. Overall there were 18 VTE events, 10 (34.5%) in those with CCC-E and 8 (13.8%) controls p = 0.046. A higher proportion of VTE occurred in those with stage III/IV disease (n=16) as compared to those with early stage (n =2) p =0.01. When considering the timing of VTE, the VTE observed in those with CCC-E occurred at presentation or with disease recurrence (8 vs 1) while nearly all VTE in the control group occurred in the postoperative period. (7 vs 2). This was statistically significant p =0.01 Conclusion: Patients with CCC-E are at increased risk of VTE compared to patients with other high- risk endometrial cancers. This is particularly true for those with advanced stage disease. Presentation with a VTE and postmenopausal bleeding should raise the suspicion for CCC-E. Likewise, in those with known CCC-E development of a VTE may be a harbinger of recurrence. Consideration should be given to extended prophylaxis in patients with CCC-E to prevent VTE. No significant financial relationships to disclose.