Risk Of Deep Vein Thrombosis In Patients Research Articles

A retrospective study of the role of preoperative ultrasonography in the detection of deep vein thrombosis in 1750 patients with gastric and colorectal cancers

BackgroundThere has been a lack of research in the past on the prevalence and risk factors associated with deep vein thrombosis (DVT) in patients with resectable gastric and colorectal cancers. The purpose of this study was to review the anatomical distribution, prevalence and risk factors associated with lower limb DVT in 1750 patients with preoperative gastric and colorectal cancers and to evaluate the role of preoperative ultrasonography in the detection of DVT in preventing postoperative pulmonary thromboembolism (PTE) in patients with gastric and colorectal cancers. MethodsA total of 1750 patients with gastric and colorectal cancers who underwent preoperative venous ultrasonography of the lower limbs were retrospectively reviewed. The risk factors associated with preoperative DVT were identified using univariate and multivariate logistic regression analysis. ResultsSeventy-three of the 1750 patients with gastric and colorectal cancers had DVT detected by preoperative venous ultrasonography of the lower limb and the incidence of lower limb DVT was 4.17 % in 1750 patients with gastric and colorectal cancers. Univariate analysis showed a higher risk of DVT in patients who met the following criteria: aged ≥80 years, female sex, the performance status ≥1, stage IV, ASA class ≥ III/IV, and hypertension. Multivariate logistic regression analysis showed that female sex, stage IV and ASA class ≥ III/IV were significantly associated with DVT before gastric and colorectal cancer surgery. ConclusionsOur study showed that female sex, stage IV and ASA class ≥ III/IV were significantly associated with DVT before gastric and colorectal cancer surgery. Routine venous ultrasonography for the lower limb can identify the risk of PTE, which is of great significance in the prevention and occurrence of PTE.

Clinical effectiveness of a pneumatic compression device combined with low-molecular-weight heparin for the prevention of deep vein thrombosis in trauma patients: A single-center retrospective cohort study.

To investigate the clinical effectiveness of a pneumatic compression device (PCD) combined with low-molecular-weight heparin (LMWH) for the prevention and treatment of deep vein thrombosis (DVT) in trauma patients. This study retrospectively analyzed 286 patients with mild craniocerebral injury and clavicular fractures admitted to our department from January 2016 to February 2020. Patients treated with only LMWH served as the control group, and patients treated with a PCD combined with LMWH as the observation group. The incidence of DVT, postoperative changes in the visual analogue scale (VAS) score, and coagulation function were observed and compared between the two groups. Excluding the influence of other single factors, binary logistic regression analysis was used to evaluate the use of a PCD in the patient's postoperative coagulation function. After excluding 34 patients who did not meet the inclusion criteria, 252 patients were were included. The incidence of DVT in the observation group was significantly lower than that in the control group (5.6% vs. 15.1%, χ2=4.605, P<0.05). The postoperative VAS scores of the two groups were lower than those before surgery (P<0.05). The coagulation function of the observation group was significantly higher than that of the control group, with a better combined anticoagulant effect (P<0.05). There were no significant differences between the two groups in preoperative or postoperative Glasgow Coma Scale scores, intraoperative blood loss, postoperative infection rate, or length of hospital stay (P>0.05). According to logistic regression analysis, the postoperative risk of DVT in patients who received LMWH alone was 1.764 times that of patients who received LMWH+PCD (P<0.05). The area under the receiver operating characteristic (AUROC) curve of partial thromboplastin time (APTT) and platelet (PLT) were greater than 0.5, indicating that they were the influence indicators of adding PCD to prevent DVT. Excluding the influence of other variables, LMWH+PCD effectively improved the coagulation function of patients. Compared with LMWH alone, LMWH+PCD could improve blood rheology and coagulation function in patients with traumatic brain injury and clavicular fracture, reduce the incidence of DVT, shorten the length of hospital stay, and improve the clinical effectiveness of treatment.

A nomogram model can predict the risk of venous thromboembolism in postoperative patients with gynecological malignancies.

To explore independent factors influencing the risk of lower extremity deep vein thrombosis during the postoperative period in patients with gynecological malignancies by constructing a predictive model. In our study, we collected 573 patients with gynecological malignancies in the postoperative period between September 2016 and September 2020, who were divided into a modeling (n=402) and verification group (n=171) according to a ratio of 7:3. Univariate and multivariate regression analyses were used to determine independent factors influencing deep vein thrombosis (DVT). A nomogram model was created and a risk score was calculated. Multivariate regression analysis showed that the independent factors affecting DVT among these patients included age, hyperlipidemia, abnormal uterine bleeding, degree of anemia, D-dimer, operation time, and intraoperative blood loss. By incorporating these factors into a nomogram, we determined that the C-index and calibration curve of the two groups both showed that the model distinguishes and fits well. Further comparing between the high- and low-risk groups, we found that the model has favorable predictive performance. The predictive nomogram for the risk of DVT in patients with gynecological malignancies in the postoperative period demonstrated good calibration and recognition accuracy. Further independent research is necessary to verify our results.

Perioperative red blood cell infusion and deep vein thrombosis in patients with femoral and pelvic fractures: a propensity score matching

BackgroundThe relationship between perioperative red blood cell (RBC) infusion and deep vein thrombosis (DVT) has not been determined.ObjectivesTo analyze the time-event relationship between perioperative RBC infusion and DVT in patients with femoral and pelvic fractures after adjusting for confounding factors and to provide reference for optimizing DVT risk factors.MethodsThe clinical data of 569 patients with femoral and pelvic fractures who received surgical treatment from May 2018 to December 2019 were retrospectively analyzed. Propensity score matching (PSM) was performed on 20 covariates of DVT. With the formation or progression of DVT after RBC infusion as the end point, the time-event relationship between perioperative RBC infusion and DVT in patients was analyzed by binary logistic regression.ResultsAfter 1:1 PSM of 569 patients included in this study, 126 patients were in the transfusion group and the non-transfusion group, respectively. Before PSM (P = 0.023, OR = 1.496 [95% CI, 1.058-2.115]), perioperative RBC infusion was associated with DVT formation for femoral and pelvic fractures. This conclusion was still obtained after PSM (P = 0.038, OR = 1.728, 95% CI = (1.031, 2.896)). The risk of DVT in patients with RBC infusion of 2-4U and > 4U is 1.833 and 2.667 times that of ≤ 2U, respectively. After excluding patients who received preoperative RBC infusion and had DVT formation or progression prior to RBC infusion, perioperative RBC infusion was still associated with the formation of DVT in femoral and pelvic fractures (P = 0.037, OR = 2.231 [95% CI, 1.049-4.745]).ConclusionPerioperative RBC infusion is one of the causes of DVT in patients with femoral and pelvic fractures, and the risk of DVT is positively correlated with the amount of RBC infusion.

Association of clinical and laboratory variables with in-hospital incidence of deep vein thrombosis in patients after acute ischemic stroke: A retrospective study.

Deep vein thrombosis (DVT) is a serious complication in patients with acute ischemic stroke (AIS). Early prediction of DVT could enable physicians to perform a proper prevention strategy. We analyzed the association of clinical and laboratory variables with DVT to evaluate the risk of DVT in patients after AIS.AIS patients admitted to the Changsha Central Hospital between January 2017 and December 2019 with length of stay in hospital ≥7 days were included. Clinical and laboratory variables for DVT at baseline were collected, and the diagnosis of DVT was confirmed by ultrasonography. Independent factors were developed by Multivariate logistic regression analysis.A total of 101 patients were included in the study. The in-hospital incidence of DVT after AIS was 19.8%(20/101). The average level of D-dimer when DVT detected was significant increased around 4-fold than that on admission (P < .001). Pulmonary infection (odds ratio [OR] = 5.4, 95%CI:1.10–26.65, P = .037)) and increased muscle tone (OR = 0.11, 95%CI:0.02–0.58, P = .010) as independent relevant factors for DVT were confirmed.Pulmonary infection as a risk factor and increased muscle tone as a protective factor for DVT were identified in patients after AIS. The level of D-dimer which increased around 4-fold compared to the initial level could be an indicator for DVT occurrence.

Expert opinion: Using of antiplatelet agents in surgery with external fixators

Expert opinion: Using of antiplatelet agents in surgery with external fixators

Effectiveness and safety of the use of antifibrinolytic agents in total-knee arthroplasty

Background:Antifibrinolytic agents have been successfully used to reduce blood transfusion demand in patients undergoing elective knee arthroplasty. The purpose of this study was to investigate different antifibrinolytic agents for patients undergoing total-knee arthroplasty (TKA).Methods:We searched the randomized controlled trials assessing the effect of antifibrinolytic agents on TKA in MEDLINE, PubMed, Embase, and the Cochrane Library. Participants are divided into antifibrinolytic agent group and control group under TKA. Double extraction technology is used and the quality of its methodology is evaluated before analysis. Outcomes analyzed included blood loss, number of blood transfusions, rates of blood transfusion, and deep vein thrombosis (DVT).Results:A total of 28 randomized controlled trials involving 1899 patients were included in this study. Compared with the control group, the antifibrinolytic agents group exhibited significantly reduced the amounts of total blood loss (weighted mean difference [WMD] with 95% confidence interval [CI]: −272.19, −338.25 to −206.4), postoperative blood loss (WMD with 95% CI: −102.83, −157.64 to −46.02), average units of blood transfusion (risk ratio with 95% CI: 0.7, 0.12 to 0.24), and average blood transfusion volumes (WMD with 95% CI: −1.34, −1.47 to −1,21). Antifibrinolytic agents significantly reduced the rate of blood transfusions and did not increase the occurrence risk of intraoperative blood loss and DVT. Several limitations should also be acknowledged such as the heterogeneity among the studies.Conclusion:The application of antifibrinolytic agents can significantly reduce blood loss and blood transfusion requirements. Additionally, these agents did not increase the risk of DVT in patients undergoing TKAs.

Postoperative aspirin use and its effect on bone healing in the treatment of ankle fractures

BackgroundThere is hesitancy to administer nonsteroidal anti-inflammatories (NSAIDs) within the postoperative period following fracture care due to concern for delayed union or nonunion. However, aspirin (ASA) is routinely used for chemoprophylaxis of deep vein thrombosis (DVT) and is gaining popularity for use after treatment of ankle fractures. The current study examines the incidence of nonunion of operative ankle fractures and risk of DVT in patients who did and did not receive postoperative ASA. MethodsA retrospective chart review was performed on all patients treated between 2008 and 2018 for ankle fractures requiring operative fixation by three Foot and Ankle fellowship trained orthopaedic surgeons at a single institution. Demographics, preoperative comorbidities, and postoperative medical and surgical complications were compared between patients who did and did not receive ASA postoperatively. For both groups, union was evaluated by clinical exam as well as by radiograph, for those with 6-week, 12-week, or 24-week follow-up. ResultsFive-hundred and six patients met inclusion criteria: 152 who received ASA and 354 who did not. Radiographic healing at six weeks was demonstrated in 95.9% (94/98) and 98.6% (207/210) respectively (p-value .2134). There was no significant difference in time to radiographic union between groups. The risk of postoperative DVTs in those with and without ASA was not significantly different (0.7% (1/137) vs 1.2% (4/323), respectively; p-value .6305). ConclusionPostoperative use of ASA does not delay radiographic union of operative ankle fractures or affect the rate of postoperative DVT. This is the first and largest study to examine the effect of ASA on time to union of ankle fractures. Level of EvidenceIII

Postoperative Aspirin Use and Its Effect on Bone Healing in the Treatment of Ankle Fractures

Category:Ankle, TraumaIntroduction/Purpose:There is hesitancy to administer nonsteroidal anti-inflammatories (NSAIDs) within the postoperative period following fracture care due to concern for delayed union or nonunion. However, aspirin (ASA) is routinely used for chemoprophylaxis of deep vein thrombosis (DVT) and is gaining popularity for use after treatment of ankle fractures. We examine the incidence of nonunion of operative ankle fractures and risk of DVT in patients who did and did not receive postoperative ASA. We hypothesize that time to clinical and radiographic union and the risk of DVT are no different.Methods:A retrospective chart review was performed on all patients treated between 2008 and 2018 for ankle fractures requiring operative fixation by three Foot and Ankle fellowship trained orthopaedic surgeons at a single institution with a minimum of 3 months follow up. Demographics, preoperative comorbidities, and postoperative medical and surgical complications were compared between patients who did and did not receive ASA postoperatively. For both groups, union was evaluated by clinical exam as well as by radiograph.Results:506 patients met inclusion criteria: 152 received ASA and 354 did not. Radiographic healing at 6 weeks was demonstrated in 95.9% (94/98) and 98.6% (207/210) respectively (p-value .2134). There was no significant difference in time to radiographic union between groups. The risk of postoperative DVTs in those with and without ASA was not significantly different (0.7% (1/137) vs 1.2% (4/323), respectively; p-value .6305).Conclusion:Postoperative use of ASA does not delay radiographic union of operative ankle fractures or affect the rate of postoperative DVT. This is the first and largest study to examine the effect of ASA on time to union of ankle fractures.

Efficacy, Safety, and Timing of Anticoagulant Thromboprophylaxis for the Prevention of Venous Thromboembolism in Patients With Acute Spinal Cord Injury: A Systematic Review.

Study Design:Systematic review.Objectives:The objective of this study was to answer 5 key questions: What is the comparative effectiveness and safety of (1a) anticoagulant thromboprophylaxis compared to no prophylaxis, placebo, or another anticoagulant strategy for preventing deep vein thrombosis (DVT) and pulmonary embolism (PE) after acute spinal cord injury (SCI)? (1b) Mechanical prophylaxis strategies alone or in combination with other strategies for preventing DVT and PE after acute SCI? (1c) Prophylactic inferior vena cava filter insertion alone or in combination with other strategies for preventing DVT and PE after acute SCI? (2) What is the optimal timing to initiate and/or discontinue anticoagulant, mechanical, and/or prophylactic inferior vena cava filter following acute SCI? (3) What is the cost-effectiveness of these treatment options?Methods:A systematic literature search was conducted to identify studies published through February 28, 2015. We sought randomized controlled trials evaluating efficacy and safety of antithrombotic strategies. Strength of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system.Results:Nine studies satisfied inclusion criteria. We found a trend toward lower risk of DVT in patients treated with enoxaparin. There were no significant differences in rates of DVT, PE, bleeding, and mortality between patients treated with different types of low-molecular-weight heparin or between low-molecular-weight heparin and unfractionated heparin. Combined anticoagulant and mechanical prophylaxis initiated within 72 hours of SCI resulted in lower risk of DVT than treatment commenced after 72 hours of injury.Conclusion:Prophylactic treatments can be used to lower the risk of venous thromboembolic events in patients with acute SCI, without significant increase in risk of bleeding and mortality and should be initiated within 72 hours.

The risk factor of preoperative deep vein thrombosis in patients undergoing total knee arthroplasty.

The objective of this retrospective study was to investigate the prevalence of asymptomatic deep vein thrombosis (DVT) and the risk of DVT in patients admitted to hospital for total knee arthroplasty (TKA). From September of 2003 to December of 2013, 322 patients admitted for TKA were eligible for this retrospective study. A diagnosis of DVT was confirmed by Doppler ultrasonography. The prevalence of silent DVT in the lower limbs in patients before TKA was assessed. The risk factors for preoperative DVT were investigated, as well as the correlation of DVT in the patient's background and medical history. Preoperative DVT was diagnosed in 56 patients (17.4%) including 3 patients with proximal DVT. Significantly elevated risks of DVT were found in patients undergoing revision TKA (p<0.01), patients with rheumatoid arthritis (RA) (p<0.005), patients with connective tissue diseases (CTDs) (p<0.05), and female patients (p<0.05) on univariate analyses. Multiple linear regression analysis showed that RA, CTDs and admission for revision TKA were independent risk factors for preoperative DVT. A high prevalence of preoperative DVT was found in patients admitted to hospital for TKA. Admission to the hospital for RA, CTDs and revision TKA were risk factors for preoperative DVT.

Nadroparin or fondaparinux versus no thromboprophylaxis in patients immobilised in a below-knee plaster cast (PROTECT): A randomised controlled trial

BackgroundThe immobilisation of the lower leg is associated with deep vein thrombosis (DVT). However, thromboprophylaxis in patients with a below-knee plaster cast remains controversial. We examined the efficacy and safety of nadroparin and fondaparinux to ascertain the need for thromboprophylaxis in these patients. MethodsPROTECT was a randomised, controlled, single-blind, multicentre study that enrolled adults with an ankle or foot fracture who required immobilisation for a minimum of four weeks. The patients were randomly assigned (1:1:1) to a control group (no thromboprophylaxis) or to one of the intervention groups: daily subcutaneous self-injection of either nadroparin (2850 IE anti-Xa=0.3ml) or fondaparinux (2.5mg=0.5ml). A venous duplex sonography was performed after the removal of the cast or earlier if thrombosis was suspected. The primary outcome was the relative risk of developing DVT in the control group compared with that in both intervention groups. This trial is registered at ClinicalTrials.gov, number NCT00881088. ResultsBetween April 2009 and December 2015, 467 patients were enrolled and assigned to either the nadroparin group (n=154), the fondaparinux group (n=157), or the control group (n=156). A total of 273 patients (92, 92, and 94 patients, respectively) were analysed. The incidence of DVT in the nadroparin group was 2/92 (2.2%) compared with 11/94 (11.7%) in the control group, with a relative risk of 5.4 (95% CI 1.2–23.6; p=0.011). The incidence of DVT in the fondaparinux group was 1/92 (1.1%), yielding a relative risk of 10.8 (95% CI 1.4–80.7; p=0.003) compared with that in the control group. No major complications occurred in any group. ConclusionThromboprophylaxis with nadroparin or fondaparinux significantly reduces the risk of DVT in patients with an ankle or foot fracture who were treated in a below-knee cast without any major adverse events.

A systematic review and meta-analysis of the use of antifibrinolytic agents in total hip arthroplasty.

Antifibrinolytic agents such as tranexamic acid (TXA), epsilon aminocaproic acid (EACA), and aprotinin are widely used to reduce bleeding and the need for transfusion in cardiac, orthopaedic, and hepatic surgery. We aimed to assess the efficacy and safety of antifibrinolytic agents in total hip arthroplasty (THA). A systematic literature search was performed using MEDLINE, PubMed, EMBASE, and Cochrane databases, as well as the reference lists of relevant articles. Only randomised controlled trials were eligible for this study. The weighted mean difference in blood loss, number of transfusions per patient, and the summary risk ratio of transfusion requirements and deep-vein thrombosis (DVT) were calculated in the antifibrinolytic agents-treated and control groups. A total of 28 randomised controlled trials involving 2,131 patients were included. Patients receiving antifibrinolytic agents had a reduced total blood loss by a mean of 389.14 ml (95% CI, -483.05 to -295.23), and the number of blood transfusions per patient by 0.65 units (95% CI, -1.19 to -0.12). Antifibrinolytic agents led to a significant reduction in transfusion requirements (RR 0.55; 95% CI, 0.43 to 0.70) and no increase in the risk of DVT (RR 0.85; 95% CI, 0.51 to 1.42). Our meta-analysis demonstrated that antifibrinolytic agents significantly reduce blood loss and blood transfusion requirements while not increasing the risk of DVT in patients undergoing total hip arthroplasty.

Elevated risk of thrombophilia in agenesis of the vena cava as a factor for deep vein thrombosis.

BackgroundCongenital absence of the inferior vena cava (AIVC) is a rare malformation which may be associated with an increased risk for deep vein thrombosis (DVT). However, the role of thrombophilia in AIVC and DVT is unknown.MethodsBetween 1982 and 2013 41 patients (12 female, 29 male, mean age 28 S.D. 11 years) were detected at the University of Düsseldorf, Germany, with AIVC. Based on medical history, clinical examination, imaging and coagulation studies, we performed on this collective a risk characterisation. Extensive literature research added further 123 published cases during 1993 and 2013. AIVC-patients were compared with iliocaval DVT-patients without AIVC (n = 168) treated during the same period in our clinic (90 female, 78 male, mean age 38 S.D. 17 years).ResultsIn contrast to classical DVT younger men were more often affected. Factor-V-Leiden-mutation, 5,10-methylenetetrahydrofolate reductase (MTHFR) polymorphism and hyperhomocysteinemia individually are associated with an increased risk of DVT in patients with AIVC. Aplasia/hypoplasia of the right or left kidney is also associated with IVCA.ConclusionsAIVC should be considered in young patients who present with DVT involving the vena cava. Analysis of publications with AIVC and our patients yielded a typical spectrum of AIVC-associated DVT characteristics: AIVC occurs in young male adults, is revealed by proximal DVT, not necessarily accused by precipitating factors like immobilisation, and is mostly located bilateral. Hereditary coagulation abnormalities seem to be more often a contributing factor for DVT in AIVC.Electronic supplementary materialThe online version of this article (doi:10.1186/s13023-014-0223-4) contains supplementary material, which is available to authorized users.

Elevated soluble platelet glycoprotein VI is a useful marker for DVT in postoperative patients treated with edoxaban.

Prevention of deep vein thrombosis (DVT) is important in patients undergoing major orthopedic surgery. Although the detection of an elevated D-dimer level is useful for predicting DVT, it is not efficacious in postoperative patients being treated with anti-Xa agents. The soluble platelet glycoprotein VI (sGPVI) level is a marker of activated platelets, but not bleeding. Therefore, sGPVI levels are usually examined as a predictor of DVT in such patients. In the present study, 83 orthopedic patients were treated with 30mg of edoxaban for prophylaxis of DVT. Fourteen patients developed DVT and 17 patients discontinued the prophylaxis due to decreased hemoglobin levels. Plasma levels of sGPVI in the patients were significantly higher after surgery than before surgery. On day 1, the sGPVI levels increased, while the platelet counts decreased. There were no significant differences in D-dimer, soluble fibrin, or FDP levels in orthopedic patients with and without DVT before surgery and on days 1, 4, and 8. Plasma sGPVI levels were significantly higher in the patients with DVT than in those without DVT on days 1 and 4. Plasma levels of D-dimer were significantly higher in patients with withdrawal than in those without. However, there were no significant differences in sGPVI levels between those with and without withdrawal. As D-dimer levels are known to increase in patients with withdrawal, this parameter is not useful for evaluating the risk of DVT in these patients. In contrast, the sGPVI level is not increased in those with withdrawal and may therefore be useful for evaluating the risk of DVT in postoperative patients treated with an anticoagulant.

AB0245 Clinical Analysis of Preoperative Deep Vein Thrombosis Risk Factors in Patients with Total Hip Arthroplasty

BackgroundVenous thromboembolism (VTE) is a common complication during and after a hospital admission. That is associated with significant morbility and mortality after orthopedic surgery. The ACCP Guidelines showed that limb...

Heparin for the prevention of venous thromboembolism in acutely ill medical patients (excluding stroke and myocardial infarction).

Venous thromboembolic disease has been extensively studied in surgical patients. The benefit of thromboprophylaxis is now generally accepted, but it is medical patients who make up the greater proportion of the hospital population. Medical patients differ from surgical patients with regard to their health and the pathogenesis of thromboembolism and the impact that preventative measures can have. The extensive experience from thromboprophylaxis studies in surgical patients is therefore not necessarily applicable to non-surgical patients. This is an update of a review first published in 2009. To determine the effectiveness and safety of heparin (unfractionated heparin or low molecular weight heparin) thromboprophylaxis in acutely ill medical patients admitted to hospital, excluding those admitted to hospital with an acute myocardial infarction or stroke (ischaemic or haemorrhagic) or those requiring admission to an intensive care unit. For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched November 2013) and CENTRAL (2013, Issue 10). Randomised controlled trials comparing unfractionated heparin (UFH) or low molecular weight heparin (LMWH) with placebo or no treatment, or comparing UFH with LMWH. One review author identified possible trials and a second review author confirmed their eligibility for inclusion in the review. Two review authors extracted the data. Disagreements were resolved by discussion. We performed the meta-analysis using a fixed-effect model with the results expressed as odds ratios (ORs) with 95% confidence intervals (CIs). Sixteen studies with a combined total of 34,369 participants with an acute medical illness were included in this review. We identified 10 studies comparing heparin with placebo or no treatment and six studies comparing LMWH to UFH. Just under half of the studies had an open-label design, putting them at a risk of performance bias. Descriptions of random sequence generation and allocation concealment were missing in most of the studies. Heparin reduced the odds of deep vein thrombosis (DVT) (OR 0.38; 95% CI 0.29 to 0.51; P < 0.00001). The estimated reductions in symptomatic non-fatal pulmonary embolism (PE) (OR 0.46; 95% CI 0.19 to 1.10; P = 0.08), fatal PE (OR 0.71; 95% CI 0.43 to 1.15; P = 0.16) and in combined non-fatal PE and fatal PE (OR 0.65; 95% CI 0.42 to 1.00; P = 0.05) associated with heparin were imprecise. Heparin resulted in an increase in major haemorrhage (OR 1.81; 95% CI 1.10 to 2.98; P = 0.02). There was no clear evidence that heparin had an effect on all-cause mortality and thrombocytopaenia. Compared with UFH, LMWH reduced the risk of DVT (OR 0.77; 95% CI 0.62 to 0.96; P = 0.02) and major bleeding (OR 0.43; 95% CI 0.22 to 0.83; P = 0.01). There was no clear evidence that the effects of LMWH and UFH differed for the PE outcomes, all-cause mortality and thrombocytopaenia. The data from this review describe a reduction in the risk of DVT in patients presenting with an acute medical illness who receive heparin thromboprophylaxis. This needs to be balanced against an increase in the risk of bleeding associated with thromboprophylaxis. The analysis favoured LMWH compared with UFH, with a reduced risk of both DVT and bleeding.

Effectiveness of intermittent pneumatic compression in reduction of risk of deep vein thrombosis in patients who have had a stroke (CLOTS 3): a multicentre randomised controlled trial

Venous thromboembolism is a common, potentially avoidable cause of death and morbidity in patients in hospital, including those with stroke. In surgical patients, intermittent pneumatic compression (IPC) reduces the risk of deep vein thrombosis (DVT), but no reliable evidence exists about its effectiveness in patients who have had a stroke. We assessed the effectiveness of IPC to reduce the risk of DVT in patients who have had a stroke. The CLOTS 3 trial is a multicentre parallel group randomised trial assessing IPC in immobile patients (ie, who cannot walk to the toilet without the help of another person) with acute stroke. We enrolled patients from day 0 to day 3 of admission and allocated them via a central randomisation system (ratio 1:1) to receive either IPC or no IPC. A technician who was masked to treatment allocation did a compression duplex ultrasound (CDU) of both legs at 7-10 days and, wherever practical, at 25-30 days after enrolment. Caregivers and patients were not masked to treatment assignment. Patients were followed up for 6 months to determine survival and later symptomatic venous thromboembolism. The primary outcome was a DVT in the proximal veins detected on a screening CDU or any symptomatic DVT in the proximal veins, confirmed on imaging, within 30 days of randomisation. Patients were analysed according to their treatment allocation. ISRCTN93529999. Between Dec 8, 2008, and Sept 6, 2012, 2876 patients were enrolled in 94 centres in the UK. The included patients were broadly representative of immobile stroke patients admitted to hospital and had a median age of 76 years (IQR 67-84). The primary outcome occurred in 122 (8·5%) of 1438 patients allocated IPC and 174 (12·1%) of 1438 patients allocated no IPC; an absolute reduction in risk of 3·6% (95% CI 1·4-5·8). Excluding the 323 patients who died before any primary outcome and 41 without any screening CDU, the adjusted OR for the comparison of 122 of 1267 patients vs 174 of 1245 patients was 0·65 (95% CI 0·51-0·84; p=0·001). Deaths in the treatment period occurred in 156 (11%) patients allocated IPC and 189 (13%) patients allocated no IPC died within the 30 days of treatment period (p=0·057); skin breaks on the legs were reported in 44 (3%) patients allocated IPC and in 20 (1%) patients allocated no IPC (p=0·002); falls with injury were reported in 33 (2%) patients in the IPC group and in 24 (2%) patients in the no-IPC group (p=0·221). IPC is an effective method of reducing the risk of DVT and possibly improving survival in a wide variety of patients who are immobile after stroke. National Institute of Health Research (NIHR) Health Technology Assessment (HTA) programme, UK; Chief Scientist Office of Scottish Government; Covidien (MA, USA).

Clinical relevance of heparin-PF4 complex antibody in DVT after total joint replacement

BackgroundAntibodies to the heparin-platelet factor-4 (HPF-4) complex (HIT antibodies) have been observed in patients with heparin-induced thrombocytopenia (HIT). These antibodies are thought to be involved in thrombosis through activation of platelet/endothelial cells. This prospective study was conducted to determine the incidence of post-operative HIT antibodies to assess the associated risk of deep vein thrombosis (DVT) in patients undergoing total knee arthroplasty (TKA) or total hip arthroplasty (THA).MethodsWe studied 104 patients who underwent unilateral primary TKA (n = 44) and primary THA (n = 60) with short-duration prophylaxis (1–2 days of a fixed dose of unfractionated heparin). HIT antibodies were assayed using a sandwich-type ELISA before the operation and after heparin treatment (post-operative day 7).ResultsIn the clinical outcome, the incidence of symptomatic DVT was 15.4% (16/104, TKA; 10, THA 6) and pulmonary embolism (PE) was not observed. The total seroconversion rate of HIT antibodies at post-operative day 7 was 34.6% (36/104). Among 36 seroconverted patients, 11 (30.6%) developed symptomatic DVT and 5 out of 68 of the non-seroconverted patients (7.4%) developed symptomatic DVT. The incidence for DVT was significantly higher in the seroconverted patients compared with that of the non-seroconverted patients (odds ratio 5.5, 95%CI: 1.7–17.6 p = 0.0028). Furthermore, in the patients with symptomatic DVT, the titer of HIT antibodies at post-operative day 7 was significantly higher compared with those without symptomatic DVT.ConclusionOur data therefore suggest that seroconversion for HIT antibodies generated by heparin is associated with a risk of DVT in patients undergoing total joint replacement.

Reduced plasma fibrinolytic potential is a risk factor for venous thrombosis

AbstractThe role of the fibrinolytic system in the development of deep vein thrombosis (DVT) is unclear. We determined the plasma fibrinolytic potential of patients enrolled in the Leiden Thrombophilia Study (LETS), a population-based case-control study on risk factors for DVT. Plasma fibrinolytic potential was determined in 421 patients and 469 control subjects by means of a tissue factor–induced and tissue-type plasminogen activator (tPA)–induced clot lysis assay. Using clot lysis times above the 70th, 80th, 90th, 95th, and 99th percentiles of the values found in control subjects as cut-off levels, we found a dose-dependent increase in risk for DVT in patients with hypofibrinolysis (odds ratios of 1.4, 1.6, 1.9, 2.1, and 2.2, respectively). This indicates a 2-fold increased risk of DVT in subjects with clot lysis times above the 90th percentile. The risk increase was not affected by age or sex (adjusted odds ratio for 90th percentile, 2.0), and after correction for all possible confounders (age, sex, and levels of procoagulant proteins shown to associate with clot lysis times in the control population), the risk estimate was marginally reduced (odds ratio, 1.6 for 90th percentile). Taken together, these results indicate that plasma hypofibrinolysis constitutes a risk factor for venous thrombosis, with a doubling of the risk at clot lysis times that are present in 10% of the population.