Factors Of Deep Venous Thrombosis Research Articles

Use of Antibiotics and Risk of Deep Venous Thrombosis in a Population without Known Risk Factors

There are conflicting reports of an association between seropositivity for Chlamydia pneumoniae and risk of deep venous thrombosis. Analyzing longitudinal data from a large claims-based dataset comprised of 166,004 enrollees, we did not find an association between use of usual short courses of anti-chlamydial antibiotics and a lower risk of deep venous thrombosis in a sample without known risk factors for deep venous thrombosis.

Risk of Venous Thromboembolism in Patients Nursed at Home or in Long-Term Care Residential Facilities

Background. This study investigated the prevalence of and impact of risk factors for deep venous thrombosis (DVT) in patients with chronic diseases, bedridden or with greatly limited mobility, cared for at home or in long-term residential facilities. Methods. We enrolled 221 chronically ill patients, all over 18 years old, markedly or totally immobile, at home or in long-term care facilities. They were screened at the bedside by simplified compression ultrasound. Results. The prevalence of asymptomatic proximal DVT was 18% (95% CI 13–24%); there were no cases of symptomatic DVT or pulmonary embolism. The best model with at most four risk factors included: previous VTE, time of onset of reduced mobility, long-term residential care as opposed to home care and causes of reduced mobility. The risk of DVT for patients with reduced mobility due to cognitive impairment was about half that of patients with cognitive impairment/dementia. Conclusions. This is a first estimate of the prevalence of DVT among bedridden or low-mobility patients. Some of the risk factors that came to light, such as home care as opposed to long-term residential care and cognitive deficit as causes of reduced mobility, are not among those usually observed in acutely ill patients.

Risk factors and therapeutic strategies of deep venous thrombosis during pregnancy

To summarize the epidemiology and risk factors of deep venous thrombosis (DVT) during pregnancy and develop therapeutic strategies. Twenty-nine pregnant women with DVT were admitted into our hospital between 1991 and 2010. And their clinical data were retrospectively reviewed. Among all cases, the occurrence (69%, 20/29) of DVT in the first trimester was highest as compared with those in the second and third trimesters. A previous history of DVT was a leading risk factor (24%, 7/29). Twenty-four cases (82.8%, 24/29) involved left lower extremities. Anticoagulation was the primary therapy. All cases were initially intravenously administrated with unfractioned heparin (UFH) or injected subcutaneously with low-molecule-weight heparin (LMWH). LMWH continued throughout pregnancy in 7 cases. The fetus had a normal development. Due to financial problems, 11 cases in the first trimester and 2 cases in the second trimester switched to oral warfarin from LMWH after the initial treatment. And warfarin was substituted by LMWH by Week 34. However the fetuses died in 4 cases while the other fetuses were normal. Nine cases in the first trimester decided to terminate pregnancy. Treatment decisions during pregnancy carry potential implications for both maternal and fetal health and life. Therefore the DVT strategies during pregnancy differ from those during non-pregnancy. Special cautions should be exercised for the treatment of DVT during pregnancy.

354: Is a Baker's Cyst on Lower Extremity Ultrasonography a Risk Factor for Concomitant Deep Venous Thrombosis?

It has been suggested that Baker's cyst is a risk factor for deep venous thrombosis (DVT). Baker's cyst and DVT may occasionally co-exist. Our primary objective is to determine the incidence of DVT in the presence of Baker's cyst. This was a retrospective chart review. All patients who had a lower extremity ultrasonography performed were included in the study. This study was performed at an urban hospital with >120,000 annual visits in the emergency department (ED). We reviewed the picture archiving and communication system (PACS) and identified patients who had lower extremity ultrasonography. The index ultrasonography was used for any patient who had multiple visits to the hospital. We stratified patients with DVT as diagnosed by lower extremity duplex sonography by the presence or absence of a Baker's cyst. Chi-square and Fisher's exact test were used for categorical data for statistical analysis. We identified 1068 patients who had a lower extremity ultrasonography from July 2005 to January 2009. Median age of all patients was 71 years (IQR 54-82 years). 56% were female and 52% were White. Baker's cyst was present in 329 patients [30.9% (95%CI 28.1-33.6%)] and DVT was present in 423 patients [39.6% (95%CI 36.7-42.5%)]. Twenty out of 329 patients with Baker's cyst also had a DVT [6.1% (95%CI 3.5-8.7%)]. DVT was present in 402 of the 739 patients in the absence of a Baker's cyst [54.6%(95%CI 50.9-58.1%)] (p<0.001). Patients with a Baker's cyst diagnosed on ultrasonography were less likely to have a simultaneously diagnosed deep venous thrombosis in this cohort of adult patients who had a lower extremity ultrasonography performed.

Polymorphisms and Mutations in vWF and ADAMTS13 Genes and Their Correlation With Plasma Levels of FVIII and vWF in Patients With Deep Venous Thrombosis

Increased levels of factor VIII (FVIII) are a prevalent and independent risk factor for deep venous thrombosis (DVT) and are affected by von Willebrand factor (vWF) levels. ADAMTS13 contributes to vWF levels, and we investigated genetic polymorphisms previously described to be associated with decreased levels of these proteins in 435 patients with DVT (126 M and 309 F; median age 37 years, range 18-68 years) and 580 controls (163 M and 417 F; median age 35 years, range 18-68 years). Subsequently, we investigated the relationship between the genotypes and plasma levels of FVIII, vWF, and DVT risk. Patients with DVT showed higher plasma levels of FVIII:C, FVIII:Ag, and vWF:Ag (P < .001) when compared to controls. Patients and controls heterozygous for the 4751A>G polymorphism in the vWF gene presented decreased levels of vWF:Ag, FVIII:Ag, and FVIII:C (P < .001), but this was not a protective factor for DVT. Individuals heterozygous for 1852C>G polymorphism in ADAMTS13 gene, which is associated with reduced levels of ADAMTS13, had significantly elevated levels of vWF:Ag (P = .001), FVIII:Ag (P = .01), and FVIII:C (P = .02). However, this polymorphism was not a risk factor for DVT in our study. Heterozygosis for a new polymorphism identified in ADAMTS13 gene, 1787-26G>A, was significantly associated with elevated levels of FVIII:C (P = .02) when compared to wild type. Despite the tempting assumption that genetic factors that change ADAMTS13 activity might modulate the risk of DVT by altering vWF and FVIII levels, the polymorphisms analyzed in this study did not correlate with DVT risk among patients investigated.

Incidence and Risk Factors for Deep Venous Thrombosis After Moderate and Severe Brain Injury

Patients with traumatic injuries possess a high risk of developing deep venous thrombosis (DVT), thus the need for appropriate prophylaxis. Patients with head injuries pose a unique challenge due to contraindication to the use of anticoagulation. We sought to determine the incidence of DVT and identify specific risk factors for its development in patients with head injuries. All head injury admissions between January 1, 2000, and July 31, 2006, with a length of stay >or=7 days were identified. Patient data including age, sex, injuries, Glasgow Coma Scale, Injury Severity Score (ISS), and venous duplex scan results were collected. Mechanical methods were routinely used for prophylaxis; heparin was not used in this population. Weekly duplex screening was commenced at 7 days to 10 days after admission. There were 939 patients who met criteria for review, however, duplex scans were performed in only 677, which was the population studied. Overall, DVT was present in 31.6%. There were fewer DVTs in patients with isolated head injuries (25.8%) compared with patients with those with head and extracranial injuries (34.3%)--p = 0.026. Independent predictors for DVT identified included male gender (p = 0.04), age >or=55 (p < 0.001), ISS >or=15 (p = 0.014), subarachnoid hemorrhage (p = 0.006), and lower extremity injury (p = 0.001). DVT occurs in one third of moderately to severely brain injured patients. Isolated head injuries have a lower incidence. Older age, male gender, higher ISS, and the presence of a lower extremity injury are strong predictors for developing DVT. Regular screening and the use of prophylactic inferior vena cava filters in patients with risk factors should be strongly considered.

Deep Venous Thrombosis After Surgery for Inflammatory Bowel Disease: Is Standard Dose Low Molecular Weight Heparin Prophylaxis Enough?

Inflammatory bowel disease (IBD) and colorectal surgery are risk factors for deep venous thrombosis (DVT). The aim of this prospective study was to evaluate the effectiveness of standardized prophylactic low molecular weight heparin (LMWH) therapy in patients who underwent surgery for ulcerative colitis (UC) and Crohn's disease (CD). Since 1999 all patients operated on for colorectal diseases in our institute have received 4,000 IU/day LMWH from the day of operation to discharge. The complete series of patients who had major colorectal surgery from 1999 until 2006 were reviewed for overt DVT episodes. Furthermore, 60 consecutive patients who were admitted for surgery for IBD were prospectively enrolled in the 2004-2006 period. Each patient underwent venous color Doppler ultrasound scan at admission and at discharge. Demographic data, disease activity, and clotting parameters were collected. Data were analyzed with Spearman's correlation test, multiple regression, and receiver operating characteristics (ROC) curves analysis. The rate of DVT in UC patients was significantly higher than in colorectal cancer patients (p = 0.009), and the odds ratio (OR) for postoperative DVT in UC patients was 7.4 (95% CI 1.4-44.4; p = 0.017). Female gender, UC diagnosis, active rectal bleeding, aPTT value, aCL IgM, abeta2 IgM, and pANCA levels significantly correlated with postoperative DVT. At multivariate analysis only aCL IgM levels were found to be independently associated with postoperative DVT (p = 0.05). In conclusion, our study showed that prophylactic therapy with 4,000 IU/day LMWH was not completely effective for the prevention of postoperative DVT in patients with CD, and even less so in those with UC. In these patients, a more tailored prophylactic therapy should be considered, and further randomized controlled trials testing the effectiveness of different prophylactic protocols would be advisable. Furthermore, aCL IgM serum levels might be helpful in identifying IBD patients who are at higher risk of postoperative DVT.

The Prevalence of and Specific Risk Factors for Venous Thromboembolic Disease Following Elective Spine Surgery

Venous thromboembolic disease, including deep venous thrombosis and pulmonary embolism, is a serious and potentially life-threatening complication following orthopaedic surgical procedures. We sought to investigate the prevalence of thromboembolism as well as the efficacy and complications of various prophylactic measures in a population of patients who had undergone elective spine surgery. A meta-analysis and univariate logistic regression were performed on selected studies to determine the prevalence of and risk factors for deep venous thrombosis and pulmonary embolism following elective spine surgery. Studies were included on the basis of the selection criteria (specifically, the inclusion of only patients undergoing spine surgery, or the treatment of patients undergoing spine surgery as an independent cohort; the use of an objective diagnostic modality for the diagnosis of deep venous thrombosis, including Doppler ultrasonography or venography; the use of an objective diagnostic modality for the diagnosis of pulmonary embolism, including computed tomography of the chest or a ventilation-perfusion scan; and a study population of more than thirty patients). Patients with a known spinal cord injury were excluded. Fourteen studies (including a total of 4383 patients) met our selection criteria. On the basis of the meta-analysis, the prevalence of deep venous thrombosis was 1.09% (95% confidence interval, 0.54% to 1.64%) and the prevalence of pulmonary embolism was 0.06% (95% confidence interval, 0.01% to 0.12%) following elective spine surgery. The use of pharmacologic prophylaxis significantly reduced the prevalence of deep venous thrombosis relative to either mechanical prophylaxis (p = 0.047) or no prophylaxis (p < 0.01). One fatal pulmonary embolism was reported. An epidural hematoma requiring surgical evacuation was reported in eight of 2071 patients receiving pharmacologic prophylaxis; three of these patients had a permanent neurologic deficit. The risk of deep venous thrombosis and pulmonary embolism is relatively low following elective spine surgery, particularly for patients who receive pharmacologic prophylaxis. Unfortunately, pharmacologic prophylaxis exposes patients to a greater risk of epidural hematoma. More evidence is needed prior to establishing a protocol for prophylaxis against venous thromboembolic disease in patients undergoing elective spine surgery. Future prospective studies should seek to define the safety of various prophylactic modalities and to identify specific subpopulations of patients who are at greater risk for venous thromboembolism.

Rheumatoid arthritis: a risk factor for deep venous thrombosis after total knee arthroplasty? Comparative study with osteoarthritis

BackgroundRecent advances in the understanding of blood coagulation processes favor an inflammatory basis for thrombotic events. In this study, thrombotic risk after total knee arthroplasty (TKA) was assessed and compared between patients with rheumatoid arthritis (RA) and those with osteoarthritis (OA). MethodsSubjects comprised 199 patients (238 knees) with RA and 156 patients (169 knees) with OA. Serum D-dimer levels were measured before and after the operation. Lowdose unfractionated heparin was given for 7 days when patients had a history of previous venous thromboembolism or had a D-dimer level or ≥10μg/ml of D-dimer on postoperative day 1. Doppler ultrasonography (DUS) was routinely performed preoperatively and on postoperative day (POD) 7 for diagnosing a deep venous thrombosis (DVT). ResultsD-dimer levels on PODs 0, 1, and 7 were, respectively, 4.6, 37.2, and 11.2μg/ml for RA and 1.8, 42.3, and 13.6 μg/ml for OA. The incidence of DUS-confirmed DVT was 20.6% in the RA group and 43.2% in the OA group, indicating a much higher incidence of postoperative DVT in OA patients (P < 0.001). Interestingly, when patients taking nonsteroidal antiinflammatory drugs (NSAIDs) or those >65 years of age were excluded, the incidence of DVT was comparable in the RA and OA groups. Symptomatic pulmonary embolism and DVT occurred in two and one OA patients and in one and two RA patients, respectively, with one postdischarge DVT included in each group. ConclusionsThe present study revealed that the incidence of DVT following TKA was significantly lower in RA patients than in those with OA. However, when the patients were matched for age and NSAID use, the incidence of DVT was equivalent in the two groups. These findings may allow us to reconsider a prophylactic regimen for venous thromboembolism in patients with RA.

A Systematic Review of Thromboprophylaxis for Pelvic and Acetabular Fractures

Pelvic and acetabular fractures have been identified as risk factors for deep venous thrombosis (DVT) and thromboembolic complications. A systematic review was performed to evaluate the effectiveness of thromboprophylactic strategies to prevent DVT or pulmonary embolism (PE) after pelvic or acetabular fractures. Relevant articles were identified by searching MEDLINE, MEDLINE In Process & Other Non-indexed Citations, EMBASE, CENTRAL, and the Cochrane Database of Systematic Reviews. All languages and years indexed were searched. Manuscripts were included if (1) the study included an intervention or strategy aimed at preventing thromboembolic disease, (2) the subjects in the study had suffered a pelvic or acetabular fracture, and (3) the primary outcome of the study was DVT or PE. The intervention, sample size, DVT, and/or PE incidence, and method of diagnosis were recorded for each study. Eleven studies with 1760 subjects were included. Included studies were grouped into 5 types of interventions: mechanical compression devices, inferior vena cava filters, low-molecular weight heparins, ultrasound screening, and magnetic resonance venography screening. Most studies were observational designs with minimal control data for comparison. Quantitative pooling was not possible based on significant study heterogeneity. Although several strategies have been used to prevent thromboembolism in pelvic and acetabular fracture patients, our results suggest that clinicians have limited data to guide their prophylactic decisions. Well-designed clinical trials to prevent and detect venous thromboembolism in pelvic and acetabular trauma are still needed.

Abstract No. 335: Iliac Vein Compression as a Risk Factor for Deep Venous Thrombosis: A Case Control Study

Abstract No. 335: Iliac Vein Compression as a Risk Factor for Deep Venous Thrombosis: A Case Control Study

Activated Protein C Resistance in Deep Venous Thrombosis

Several risk factors for deep venous thrombosis (DVT) have been identified, and inherited thrombophilias constitute a significant proportion of them. The most common inherited thrombophilia is activated protein C (APC) resistance, and factor V Leiden is the most common cause of APC resistance. The high prevalence of APC resistance in Caucasians is established, and the prevalence among persons of Asian and African descent has been shown to be low in previous studies. Twenty-three patients with lower limb DVT were included in the study. Diagnosis was confirmed by duplex ultrasonography. Patients were tested for APC resistance with use of the STA Staclot APC-R system (Diagnostica Stago, Asnieres, France), as per the manufacturer's guidelines. Ten patients (43.5%) tested positive for APC resistance, while 13 (56.5%) tested negative. APC resistance, although considered a rarity, has been found to have a high prevalence in patients with DVT from the northeastern region of India. APC resistance estimation should be done for all patients with DVT.

Alteration in coagulation profile and incidence of DVT in laparoscopic cholecystectomy

Introduction Although laparoscopic cholecystectomy appears to be less traumatic to the patients than open surgery, decreased venous return from lower extremities and hypercoagulability occurring in patients undergoing elective laparoscopic cholecystectomy with CO 2 pneumoperitoneum makes it a potent risk factor for deep venous thrombosis. Methods The observational study of 50 patients undergoing elective laparoscopic cholecystectomy was designed to study alteration in PT, APTT, d-dimer and antithrombin III, which were measured preoperatively, 6 and 24 h postoperatively. It was accompanied by color duplex ultrasound of bilateral lower limbs preoperatively and 7th day postoperatively to look for evidence of deep venous thrombosis. Results Significant postoperative decrease in APTT and antithrombin III suggested activation of coagulation while decrease in d-dimer suggested activation of fibrinolysis. Values of PT had no statistically significant postoperative changes. Age, body mass index and duration of pneumoperitoneum were found to correlate with significant activation of coagulation and fibrinolysis. None of the patients developed clinical or radiological evidence of deep venous thrombosis in the postoperative period. Conclusions CO 2 pneumoperitoneum enhances the activation of coagulation and fibrinolysis associated with laparoscopic cholecystectomy. Patients with risk factors like old age, obesity or with expected long duration of laparoscopic surgery are likely to have significant activation of coagulation, making them a vulnerable risk group for development of postoperative deep vein thrombosis, warranting some form of thromboprophylaxis.

Determination of risk factors for deep venous thrombosis in hospitalized children

Purpose Our objective was to determine the time trend and risk factors for deep venous thrombosis (DVT) of the lower extremities among pediatric inpatients. Methods This cross-sectional study used the data from the Health Care Cost and Utilization Project Kids' Inpatient Database for the years of 1997, 2000, and 2003 to estimate the DVT prevalence and crude and adjusted prevalence ratios. Patients between the ages of 1 and 17 years and who were hospitalized for at least 4 days were included. Results The weighted prevalence of DVT was 4.2 per 1000 hospital discharges (95% confidence interval [CI], 3.4-3.7). Independent of age, the prevalence of DVT was significantly greater in 2000 and 2003 compared to 1997, prevalence ratio (PR) of 1.2 and 1.4 (95% CI, 1.1-1.3 and 1.2-1.4). Using only the 2003 database, adjusted analysis revealed that patients at highest risk were those in the age range of 15 to 17 years (PR, 2.0; 95% CI, 1.6-2.4) and with the following comorbid conditions: obesity (PR, 2.1; 95% CI, 1.5-2.8), inflammatory bowel disease (PR, 1.8; 95% CI, 1.2-2.7), hematologic malignancy (PR, 2.5; 95% CI, 2.0-3.1), and thoracoabdominal (PR, 1.8; 95% CI, 1.6-2.2) or orthopedic (PR, 2.2; 95% CI, 1.7-2.8) operations. Predictors not associated with DVT included sex and diagnosis of trauma. Conclusions The discharge diagnosis of DVT of the lower extremities has significantly increased since 1997. In addition, teenagers with underlying disorders are at highest risk for DVT.

Janus Kinase (JAK2) V617F Somatic Mutation in Patients with Deep Vein Thrombosis.

Background: Myeloproliferative disorders are a risk factor for deep venous thrombosis. The most common venous event is deep vein thrombosis of the lower limbs, cerebrovascular thrombosis is one of the major causes of morbidity and mortality among patients with MPD and splanchnic vein thrombosis are frequent in patients with latent MPD. The recently identified Janus kinase (JAK2) V617F somatic mutation is an acquired mutation frequently found in MPD patients and has been related to a higher risk of vascular events among those patients.Objective: Determine the presence of JAK 2 V617F mutation among patients with deep venous thrombosis of the lower limbs, splanchnic veins and central nervous systems without overt MPD.Patients and methods: We accessed the medical histories of 240 adult patients with the diagnosis of deep vein thrombosis who have been treated in the Haematology Department of the State University of Campinas, 63 patients with splanchnic vein thrombosis, 126 patients with deep vein thrombosis of the lower limbs and 51 patients with central nervous system vein thrombosis. The DNAs obtained at the diagnosis of all those 240 patients were than tested for the JAK 2 V617F mutation by polimerase chain reaction followed by restriction enzyme analysis. None of them fulfilled criteria for diagnosis of MPD at the time of the thrombosis.Results: The three groups were similar with regard to age of the thrombosis, platelets and hemoglobin values at the diagnosis. There was also no diference between the three groups regarding the presence of hereditary thrombofilia and antiphospholipid antibodies. Females accounted for 47% of the patients with splanchnic vein thrombosis, 72.2% in thrombosis of the lower limbs and 74% in central nervous system (p values of 0.0013 and 0.042 respectively). The median neutrophils values at diagnosis were significantly lower among patients with splanchnic vein thrombosis compared with patients with thrombosis of the lower limbs or central nervous system (p= 0.007 and p= 0.004 respectively). The thrombotic event was provoked in 23.8% of patients with splanchnic vein thrombosis versus 57.8% in thrombosis of the lower limbs (95% CI 0.12–0.45, p<0,001) and versus 43% in central nervous system thrombosis (95% CI 0.18–0.92, p =0,043). The number of provoked events was similar between patients with thrombosis of the lower limbs and central nervous system. No homozygous JAK 2 V167F mutation was found. The heterozygous JAK 2 V167F mutation was detected in 5 patients (7.9%) with splanchnic vein thrombosis versus none in deep vein thrombosis of the lower limbs (95%CI 1.29–437.6, p=0.003) and versus none in central nervous system vein thrombosis (95% CI 0.52–179.5, p= 0,06). Patients carrying the JAK 2 V167F mutation were all negative for Factor V Leiden, Factor II 20210A and antiphospholipid antibodies. Two out of the 5 patients had a provoked thrombosis, all related to conjugated strogens intake. Within a median follow up of 3.6 years, only one patient developed a Myeloproliferative disorder (Primary Myelofibrosis).Conclusion: The JAK2 V167F mutation in frequently present in cases of splanchnic vein thrombosis without overt MPD but not in case of deep vein thrombosis of the lower limbs and probability not in cases of central nervous system vein thrombosis. The further development of MPD in the positive JAK2 V167F mutation cases is yet to be determined.

A case control study of deep venous thrombosis in relation to factor V G1691A (Leiden) and A4070G (HR2 Haplotype) polymorphisms

Activated protein C resistance (APCR) is a significant risk factor for venous thromboembolism (VTE), with the factor V (FV) G1691A (Leiden) mutation accounting for the majority of inherited APCR cases. An additional FV polymorphism, A4074G (FV-HR2), reportedly increased VTE risk by some, but not all groups. We determined the prevalence of FV-Leiden and FV-HR2 SNPs in 126 patients with deep venous thrombosis (DVT), and 197 control subjects. Frequencies of FV-Leiden A and HR2 G alleles, together with FV-Leiden G/A and A/A (but not HR2 A/G) genotypes were significantly higher among patients. While no significant linkage disequilibrium was noted between FV 1691A and 4070G or A alleles, significantly higher prevalence of single-mutant 1691G/4070G and 1691A/4070A haplotypes were seen in patients. FV Leiden and FV HR2 haplotype are independent risk factors for DVT, and their coinheritance does not seem to increase significantly DVT risk imparted by either.

Occult malignancy in patients with venous thromboembolism: risk indicators and a diagnostic screening strategy

The study was designed to analyse the risk indicators for a possible underlying malignancy and to evaluate whether extensive cancer screening is necessary in all patients with venous thromboembolism or not. In total, 126 patients with idiopathic deep venous thrombosis, and 121 patients with secondary deep venous thrombosis of lower extremity and without a known malignancy were studied. A diagnostic screening workup including a clinical history, physical examination, complete blood count, blood sedimentation rate, basic biochemistry panel including hepatic and renal function tests, prostate-specific antigen, a chest X-ray and an abdominopelvic ultrasonography was performed for all patients. Suspicious findings suggesting an underlying cancer, previous history of venous thromboembolism, bilateral venous thrombosis and associated thrombosis in unusual sites were significantly more common in patients with idiopathic venous thrombosis. A malignancy was detected in 10 of the 126 patients (7.9%) without a known risk factor for deep venous thrombosis. During the follow-up period, a diagnosis of malignancy was established in two patients in the same group. The risk of an underlying malignancy in patients with idiopathic venous thromboembolism is significantly higher. A moderate screening strategy has the capacity to identify the majority of the malignancies in such patients. We advocate simple laboratory tests, a chest X-ray and an abdominopelvic ultrasonography in order to search for an occult malignancy. A more extensive screening strategy may be considered for patients with suspicious findings for cancer, recurrent or bilateral venous thromboembolism and associated thrombosis in unusual sites.

Inherited risk factors for deep venous thrombosis following total hip arthroplasty in Japanese patients: matched control study

BackgroundInherited predisposing risk factors for deep venous thrombosis (DVT) have been clearly identified in Caucasians, but there are fewer reports evaluating these factors in the Japanese. This study was undertaken to assess the predisposing risk factors for DVT following elective total hip arthroplasty (THA) in Japanese patients. MethodsWe studied 60 patients who underwent THA. The study group consisted of 30 patients who developed DVT diagnosed by duplex sonography examination; the 30 patients who did not develop DVT served as a control group. They were matched in age, sex distribution, diagnosis (osteoarthri-tis secondary to dysplastic hip), and operation side(s) (bilateral or unilateral). Protein C, protein S, antithrombin III, and plasminogen activities and the plasma homocysteine level were measured. Three polymorphisms were screened for the factor V Leiden polymorphism, the factor II G20210A polymorphism, and the methylene tetrahydrofolate reductase C677T polymorphism. ResultsPlasma protein C activity was 82.39% ± 14.24% in the DVT patients and 88.76% ± 23.27% in the controls. Plasma protein C activity was significantly reduced in the study group, whereas other serologic and genetic analyses revealed no significant differences. ConclusionsThree genetic risk factors established in Caucasian patients are not valuable for evaluating DVT risk in Japanese patients. Reduced protein C activity may be a risk factor for DVT after THA.

Risk Factors and Presentation of Deep Venous Thrombosis among Asian Patients: A Hospital-Based Case-Control Study in Singapore

Deep venous thrombosis (DVT) is perceived to occur less frequently among Asians than Caucasians, although the reason for this has not been fully understood. Hence, there may be differences in risk factors and presentations among Asian patients compared to their Caucasian counterparts. This study examined the association of classical risk factors and presentations among Asian patients with DVT. We retrospectively reviewed 862 symptomatic patients referred to the vascular diagnostic laboratory in a hospital for suspected DVT over a 30-month period. Two hundred and seventy-seven patients (32.1%) tested positive for DVT on duplex ultrasound. After adjusting for age and gender, ethnicity was not a statistically significant demographic factor associated with DVT. Two hundred and seventy-one patients diagnosed as having DVT on ultrasound were matched for age, gender, and ethnicity to negative controls to study the significance of risk factors and presenting symptoms or signs. In multivariate analysis, independent risk factors for DVT included immobility (odds ratio [OR] = 2.61, 95% confidence interval [95% CI] 1.63-4.15], malignancy (OR = 1.77, 95% CI 1.01-3.10), and a history of thrombophilia (OR = 9.95, 95% CI 1.26-78.87). The significant forms of DVT presentation were limb swelling (OR = 2.53, 95% CI 1.41-4.54) and pulmonary embolism (OR = 11.45, 95% CI 3.23-40.59). Fever of more than 37.5 degrees C was a negative predictive factor (OR = 0.42, 95% CI 0.23-0.76). This study shows that the common risk factors of DVT such as surgery and fractures do not affect Asians as much as Caucasians. Instead, thrombophilia and underlying malignancy are prominent risk factors among Asians. Diagnosis of DVT in Asians based on clinical grounds can also be problematic as few presentations are specific.

Ultrasound evaluation and risk factors for deep venous thrombosis in the intensive care unit

Critically ill patients have a high risk of deep venous thrombosis (DVT); however, data about prevalence and specific risk factors in the ICU are conflicting and the prophylaxis strategies are still debated. The aim of this study is to evaluate the prevalence and risk factors in an ICU dealing with trauma and major surgery patients.