Symptomatic Deep Vein Thrombosis Research Articles

An observational study on the use of low-molecular-weight heparin for venous thromboembolism prophylaxis in acute stroke patients

Venous thromboembolism (VTE) including deep vein thrombosis (DVT) and pulmonary embolism (PE) are common complications post-stroke. The UK stroke guidelines recommend the early use of intermittent pneumatic compression devices (IPCDs). At our center, we noticed poor compliance with the use of these devices and sought to develop a pathway for early implementation of low-molecular-weight heparins (LMWH) instead. We retrospectively analyzed the data of 2351 patients in two separate groups and compared both groups to check the incidence of PEs and DVTs as stated on the discharge documentation. Group A consists of 1599 patients who used IPCDs as VTE prophylaxis, whereas Group B involved 752 patients who were placed on the new VTE prophylaxis protocol, which involved the early use of LMWH with enoxaparin delivered subcutaneously. It was observed that IPCDs were not well tolerated by patients, leading to poor compliance with VTE prophylaxis in Group A. VTE compliance was noted to be better in Group B in which the patients were given LMWH in the hospital. Furthermore, symptomatic DVT and PE were not found to be higher in Group B patients, but in fact, the incidence of these conditions was lower in this group. In conclusion, compared to IPCDs, LMWH appears to be well tolerated by patients during the admission period owing to acute stroke. It was observed that the incidence of VTE was reduced in patients who started on early LMWH in the post-stroke period. However, the long-term effects of LMWH prophylaxis, in terms of mortality and morbidity, need to be delineated. Therefore, an additional large trial on the early use of LMWH in comparison to IPCDs is warranted.

Prevalence and risk factors of symptomatic venous thromboembolism in distal femur fractures.

There is a paucity of published research on symptomatic venous thromboembolism (sVTE) after distal femur fractures (DFFs). This study aimed to explore the prevalence and risk factors of sVTE in DFFs. We identified a total of 131 patients who underwent DFF surgeries without routine pharmacological thromboprophylaxis between October 2007 and November 2016. Cases of sVTE included symptomatic pulmonary embolism (sPE) and symptomatic deep vein thrombosis (sDVT). Patients with sVTE were compared to those without, and differences in demographics and fracture-related characteristics were explored. Multivariate logistic regression was used to eliminate confounding factors. Of the 131 patients, 20 (15.3%) had sVTE, of whom 16 (12.2%) had sDVT and six (4.6%) had sPE (two patients had both sPE and sDVT). Notably, 17 (85.0%) sVTE patients were aged ≥60 years, while only 62 (55.9%) non-sVTE patients were aged ≥60 years (P = 0.014). Fourteen (82.4%) patients with sVTE had body mass index (BMI) ≥25 kg/m2, while 49 (53.3%) patients without sVTE had BMI ≥25 kg/m2 (P = 0.032). Multivariate logistic regression demonstrated that age ≥60 years (adjusted odds ratio [OR] 5.05; P = 0.040) and BMI ≥25 kg/m2 (adjusted OR 3.92; P = 0.045) were independently associated with a higher risk of sVTE after DFF. The prevalence of sVTE in DFFs is high at 15.3%. Advanced age (≥60 years) and being overweight (BMI ≥25 kg/m2) were two independent risk factors for sVTE in DFFs. The use of routine pharmacological thromboprophylaxis should be considered as a preventative measure.

Apixaban vs Aspirin in Patients With Cancer and Cryptogenic Stroke

Approximately 10% to 15% of ischemic strokes are associated with cancer; cancer-associated stroke, particularly when cryptogenic, is associated with high rates of recurrent stroke and major bleeding. Limited data exist on the safety and efficacy of different antithrombotic strategies in patients with cancer and cryptogenic stroke. To compare apixaban vs aspirin for the prevention of adverse clinical outcomes in patients with history of cancer and cryptogenic stroke. Post hoc analysis of data from 1015 patients with a recent cryptogenic stroke and biomarker evidence of atrial cardiopathy in the Atrial Cardiopathy and Antithrombotic Drugs in Prevention After Cryptogenic Stroke (ARCADIA) trial, a multicenter, randomized, double-blind clinical trial conducted from 2018 to 2023 at 185 stroke centers in North America. Data analysis was performed from October 15, 2023, to May 23, 2024. Oral apixaban, 5 mg (or 2.5 mg if criteria met), twice daily vs oral aspirin, 81 mg, once daily. Subgroups of patients with and without cancer at baseline were examined. The primary outcome for this post hoc analysis was a composite of major ischemic or major hemorrhagic events. Major ischemic events were recurrent ischemic stroke, myocardial infarction, systemic embolism, and symptomatic deep vein thrombosis or pulmonary embolism. Major hemorrhagic events included symptomatic intracranial hemorrhage and any major extracranial hemorrhage. Among 1015 participants (median [IQR] age, 68 [60-76] years; 551 [54.3%] female), 137 (13.5%) had a history of cancer. The median (IQR) follow-up was 1.5 (0.6-2.5) years for patients with history of cancer and 1.5 (0.6-3.0) years for those without history of cancer. Participants with history of cancer, compared with those without history of cancer, had a higher risk of major ischemic or major hemorrhagic events (hazard ratio [HR], 1.73; 95% CI, 1.10-2.71). Among those with history of cancer, 8 of 61 participants (13.1%) randomized to apixaban and 16 of 76 participants (21.1%) randomized to aspirin had a major ischemic or major hemorrhagic event; however, the risk was not significantly different between groups (HR, 0.61; 95% CI, 0.26-1.43). Comparing participants randomized to apixaban vs aspirin among those with cancer, events included recurrent stroke (5 [8.2%] vs 9 [11.8%]), major ischemic events (7 [11.5%] vs 14 [18.4%]), and major hemorrhagic events (1 [1.6%] vs 2 [2.6%]). Among participants in the ARCADIA trial with history of cancer, the risk of major ischemic and hemorrhagic events did not differ significantly with apixaban compared with aspirin. ClinicalTrials.gov Identifier: NCT03192215.

Deep vein thrombosis secondary to an ovarian tumor – approach in low resource settings: A case report

We present a case of a 37-year-old woman who exhibited symptomatic acute deep vein thrombosis (DVT) due to extrinsic compression from a giant ovarian cyst, detected during clinical examination. Doppler ultrasound confirmed a thrombus in the left iliac vein. Although surgery was initially planned to insert a vena cava filter, the absence of this resource during her 14-day hospital stay led to the decision to proceed without it. The surgery was carried out without complications, and she was discharged on the second postoperative day. A 3-month follow-up indicated favorable recovery.

Pharmacomechanical Thrombectomy and Catheter-Directed Thrombolysis, with or without Iliac Vein Stenting, in the Treatment of Acute Iliofemoral Deep Vein Thrombosis.

This study aims to evaluate and compare the outcomes and clinical efficacy of pharmacomechanical thrombectomy (PMCT) plus catheter-directed thrombolysis (CDT) and PMCT combined with CDT and venous stenting in managing acute iliofemoral deep vein thrombosis (DVT), while also assessing the long-term safety and efficacy of these interventions. A retrospective case-control study spanning 3 years involved 112 patients presenting with acute symptomatic iliofemoral deep vein thrombosis (DVT), each with a symptom duration of less than 14 days. Patients were consecutively categorized into two groups based on individual clinical indications: PMCT + CDT vs. PMCT + CDT + venous stent. Statistical analyses were conducted to compare clinical features and outcomes between the two groups. Additionally, patients were followed up for 24 months post-treatment, during which quality of life (QoL) and severity of post-thrombotic syndrome (PTS) were analyzed. In this retrospective study, we analyzed a total of 112 consecutive patients, with 63 patients undergoing PMCT + CDT and 49 patients undergoing PMCT + CDT + venous stent. Between the two groups, regarding primary outcomes at 6 months, there was no difference in the observed cumulative patency rates, standing at 82.5% for PMCT + CDT and 81.6% for PMCT + CDT + stent. Survival analyses for primary, primary-assisted, and secondary patency yielded comparable results for PMCT + CDT, with p-values of 0.74, 0.58, and 0.72, respectively. The two-year patency rate was high in both groups (85.7% for PMCT + CDT vs. 83.7% for PMCT + CDT + stent). Additionally, during the follow-up period, there were no statistically significant differences observed in the incidence of PTS or the average Villalta score between the two groups. At 24 months post-intervention, the incidence of post-thrombotic syndrome (PTS) was 11.1% in the PMCT + CDT group and 22% in the PMCT + CDT + stent group (p = 0.381). Both treatment arms of the study groups experienced bleeding complications during the thrombolysis therapy; in the PMCT + CDT group, there were three cases of gastrointestinal bleeding, compared to two cases in the PMCT + CDT + stent group (p = 0.900). Additionally, there was one intracranial hemorrhage in the PMCT + CDT group and two in the PMCT + CDT + stent group. Pharmacomechanical thrombectomy (PMCT) combined with catheter-directed thrombolysis (CDT) therapy has shown significant efficacy in alleviating leg symptoms and reducing the occurrence of post-thrombotic syndrome (PTS), including the incidence of moderate-to-severe PTS. On the other hand, the utilization of PMCT + CDT + stent therapy, tailored to individual patients' clinical and venous conditions, may enhance long-term venous patency and lead to superior outcomes, including improved quality of life parameters.

Emergency medicine residents’ learning curve in diagnosing deep vein thrombosis with 3-point venous point-of-care ultrasound

BackgroundMany cases of deep vein thrombosis (DVT) are diagnosed in the emergency department, and abbreviated lower extremity venous point-of-care ultrasound (POCUS) has already shown an accuracy comparable to that of specialists. This study aimed to identify the learning curve necessary for emergency medicine (EM) residents to achieve expertise-level accuracy in diagnosing DVT through a 3-point lower extremity venous POCUS.MethodsThis prospective study was conducted at an emergency department between May 2021 and October 2022. Four EM residents underwent a one-hour POCUS training session and performed DVT assessments in participants with DVT symptoms or confirmed pulmonary embolism. POCUS was performed at three proximal lower extremity sites to evaluate the thrombi presence and vein compressibility, with results validated by specialized radiology ultrasound. Cumulative sum (CUSUM) and the Bush and Mosteller models were used to analyze the learning curve, while generalized estimating equations were used to identify factors affecting diagnostic accuracy.Results91 POCUS scans were conducted in 49 patients, resulting in 22% DVT confirmed by specialized venous ultrasound. In the CUSUM analysis, all four EM residents attained a 90% success rate at the common femoral vein, whereas only half achieved this rate when all three sites were considered. According to Bush and Mosteller models, 13–18 cases are required to attain 90–95% diagnostic accuracy. After 10–16 cases, the examination time for each resident decreased, and a 20% increase in examiner confidence was linked to a 2.506-fold increase in the DVT diagnosis accuracy.ConclusionEM residents generally required 13–18 cases for 90–95% DVT diagnostic accuracy, but proficiency varied among individuals, particularly requiring more cases for regions outside the common femoral vein.

Effect of a 3-Month Single-Drug Approach Using Rivaroxaban for Symptomatic Proximal Deep Vein Thrombosis.

Background: Factor Xa inhibitors, such as rivaroxaban, are increasing the convenience of treatment for deep vein thrombosis (DVT). Limited evidence exists regarding clot evaluation at 3 months after treatment for DVT. Methods and Results: We retrospectively analyzed the clinical course of symptomatic proximal DVT in patients who received 3 months of anticoagulation treatment at our hospital. Patients treated with the rivaroxaban single-drug approach were classified as group A (n=42). Patients treated with unfractionated heparin (UFH) or subcutaneous fondaparinux followed by vitamin K antagonist comprised group B (n=60) as an historical cohort. The quantitative ultrasound thrombosis (QUT) score was used to quantify clot burden before and after treatment. No significant differences were observed in patient characteristics between the groups. Serum D-dimer levels in both groups significantly improved after treatment. Clot volume assessed using QUT also reduced significantly in both groups. The QUT score in groups A and B improved from 7.5 [4.8, 12.0] to 3.0 [1.8, 5.0; P=0.000] and 7.0 [4.0, 9.8] to 3.0 [2.0, 5.0; P=0.000], respectively. The change in QUT (∆QUT) was significantly greater in group A compared with group B (-4.5 [-8.25, -2.0] vs. -2.0 [-6.0, 0.0]; P=0.005). Conclusions: We were able to demonstrate the effectiveness of DVT treatment using rivaroxaban over a period of 3 months from onset, in terms of clot regression evaluated using the QUT score.

Structured benefit-risk assessment for enoxaparin, in the context of its label extension, for the extended treatment of deep vein thrombosis and pulmonary embolism, and prevention of its recurrence in patients with active cancer.

Guidelines recommend low-molecular-weight heparins (LMWHs) for patients with cancer-associated thrombosis. However, until recently, only dalteparin and tinzaparin were approved in the European Economic Area (EEA) for these patients. This study compares the benefit-risk profile of enoxaparin with dalteparin and tinzaparin for the extended treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE), and prevention of recurrence in adult patients with active cancer. A semi-quantitative structured benefit-risk assessment was conducted for the label-extension application of enoxaparin based on the benefit-risk action team descriptive framework: define decision context; determine key benefit and risk outcomes; identify data sources; extract data; interpret results. The key benefits were defined as reduced all-cause mortality and venous thromboembolism (VTE) recurrence (including symptomatic DVT, fatal PE or non-fatal PE); the key risks were major and non-major bleeding of clinical significance, and heparin-induced thrombocytopenia (HIT). Enoxaparin demonstrated comparable effects for the reduction of VTE recurrence and all-cause mortality versus other EEA-approved LMWHs (dalteparin, tinzaparin). There was no evidence of a significant difference between enoxaparin and the comparator groups with regard to incidence of major and non-major bleeding. The data on HIT were too limited to assess the difference between the two groups. The assessment demonstrated a favourable benefit-risk profile for enoxaparin similar to that of other EEA-approved LMWHs for the treatment of DVT and PE and the prevention of recurrence in patients with active cancer and thus supported the label-extension approval.

Exploring the Risk Factors for Deep Vein Thrombosis after Percutaneous Nephrolithotomy.

Deep vein thrombosis (DVT), a frequent complication following percutaneous nephrolithotomy (PCNL), may lead to severe conditions like pulmonary embolism. Current knowledge on postoperative DVT risk factors is, however, limited. The aim of our study was to investigate the risk of DVT after PCNL. A retrospective study was conducted on patients who underwent PCNL from March 2020 to March 2023 at our institution. Patient demographics and clinical data, including, DVT-specific information, preoperative labs, and surgical details, was evaluated. One hundred patients were included. Thirty-two (20 males, 12 females, mean age 52.5 ± 7.4 years) developed lower limb DVT post-surgery, while the remaining 68 (48 males, 20 females, mean age 51.1 ± 5.5 years) had no DVT symptoms. Analysis revealed significant correlations between hyperlipidemia, operating time, postoperative bed rest duration, D-dimer level on the first day after surgery, Caprini risk assessment model (RAM) score, and DVT risk. D-dimer on the first day after percutaneous nephrolithotomy, postoperative bed rest time and Caprini RAM scores were independent risk factors for DVT after PCNL. Sex, age, hypertension status, diabetes status and smoking and drinking habits were not significantly associated with DVT risk. D-dimer on the first day after PCNL, postoperative bed rest time and Caprini RAM scores were independent risk factors for DVT after PCNL.

EVALUATING THE BLOOD-SPARING EFFICACY AND SAFETY OF TRANEXAMIC ACID IN TOTAL KNEE ARTHROPLASTY

Objectives: Tranexamic acid (TXA) is an antifibrinolytic agent that effectively reduces bleeding both during and after surgery. The purpose of our study was to assess the effectiveness and safety of TXA use in reducing blood loss in uncomplicated primary total knee arthroplasty (TKA) without complications. Methods: This is a prospective, open-label, comparative study that includes patients who are undergoing unilateral primary TKA. The patients were divided into two groups: Group I, which is a control group, did not receive any doses of TXA, and Group II received three doses of intravenous TXA: 15 mg/kg TXA was administered 30 min before incision, followed by post-operative doses of 10 mg/kg TXA at 3 and 6 h. The primary objectives of the study were to measure the total blood loss (TBL) and Hemoglobin (Hb) drop, which were calculated preoperatively and on the third post-operative day. The secondary objectives were to determine transfusion rates, incidences of symptomatic deep vein thrombosis, and thromboembolic events (TE). Results: In this study, a total of 57 patients underwent unilateral TKA. The TBL in Group I was 861.67±167.65 mL, compared to 780.05±158.05 mL in Group II (p<0.001). The study also found that the Hb drop was significantly lower (2.78±0.36 vs. 2.3±0.37) with IV TXA. Furthermore, neither group required transfusions, nor were any thromboembolic complications noted for up to 6 months post-operation. Conclusion: Our study supports the use of TXA in TKA, as it effectively reduces perioperative blood loss, decreases the need for blood transfusions, and does not increase the risk of TE.

Management of Deep Vein Thrombosis: An Update Based on the Revised AWMF S2k Guideline.

Deep vein thrombosis (DVT) and pulmonary embolism (PE) are the most common manifestations of venous thromboembolism (VTE). Most DVTs affect the lower-extremity veins. Since the symptoms of DVT are non-specific, a prompt and standardised diagnostic work-up is essential to minimise the risk of PE in the acute phase and to prevent thrombosis progression, post-thrombotic syndrome and VTE recurrence in the long-term. Only recently, the AWMF S2k guidelines on Diagnostics and Therapy of Venous Thrombosis and Pulmonary Embolism have been revised. In the present article, we summarize current evidence and guideline recommendations focusing on lower-extremity DVT (LEDVT). Depending on whether the diagnostic work-up is performed by a specialist in vascular medicine or by a primary care physician, different diagnostic algorithms are presented that combine clinical probability, D-dimer testing and diagnostic imaging. The diagnosis of ipsilateral recurrent DVT poses a particular challenge and is presented in a separate algorithm. Anticoagulant therapy is an essential part of therapy, with current guidelines clearly favouring regimens based on direct oral anticoagulants over the traditional sequential therapy of parenteral anticoagulants and vitamin K antagonists. For most DVTs, a duration of therapeutic-dose anticoagulation of at least 3 to 6 months is considered sufficient, and this raises the question of the risk of VTE recurrence after discontinuation of anticoagulation and the need for secondary prophylaxis in the long-term. Depending on the circumstances and trigger factors that have contributed to the occurrence of DVT, management strategies are presented that allow decision-making taking into account the individual bleeding risk and patient's preferences.

Prevalence of symptomatic deep vein thrombosis (DVT) in patients with temporary double lumen dialysis femoral catheterization-Experience from Multan institute of kidney diseases Multan (MIKD).

Objective: The study was conducted in Multan institute of kidney diseases to explore the DVT prevalence after double lumen dialysis femoral catheterization for haemodialysis.
 Methodology: Retrospective cross sectional study was conducted in Multan Institute of Kidney Diseases, all double lumen dialysis femoral catheters passed over a period of five years (sep-2017 to sep-2022) were included in study, identified from electronic system of hospital. Except for those with temporary femoral catheters, all patients met the exclusion criteria. SPSS version 25 was used for data analysis and prevalence of DVT was calculated.
 RESULTS: Total 6628 patients with a mean age of 48(range 14 -90 years) were catheterized, 4105(61.9%) males and 2523(38.1%) were females, right sided catheters were 1826(27.5%) and 4802(72.5%) patients underwent left sided insertions. Duplex ultrasound was done of all symptomatic 252(3.8%) patients and femoral DVT was confirmed in 174(2.6%) that is 69% of symptomatic patients. The incidence of DVT significantly (3.7 fold) increase at day six and onward. Prevalence of DVT is 2.6% in all catheterized and 69% of symptomatic patients.
 Conclusion: Femoral vein remains an important emergency haemodialysis access route. Physicians inserting femoral venous catheters should be aware of the risk of lower extremity DVT from day three and consider performing duplex ultrasound examinations at day five and onwards if it is extremely necessary to be kept in situ for this duration, otherwise attention should be paid gaining access elsewhere at earliest possible opportunity.

Management and outcomes of superficial vein thrombosis: a single-center retrospective study

BackgroundGuidelines suggest but cannot recommend the optimal management of superficial vein thrombosis (SVT). ObjectivesTo identify the prevalence of asymptomatic deep vein thrombosis (DVT) at the time of SVT diagnosis, and to report the treatment and 3-month complications of patients with only SVT more than 3 cm from deep vein junction (or unknown distance). MethodsWe performed a single-center retrospective review of patients referred to the Ottawa Hospital thrombosis unit with ultrasound (US)-diagnosed SVT, and followed patients with only SVT for 3 months. ResultsThree hundred sixteen patients with SVT were included. Of the 218 patients without DVT symptoms at presentation, 19 (8.7%; 95% CI, 5.7%-13.2%) were found to have asymptomatic concomitant DVT (11 proximal and 8 distal), and 45 (20.6%) had SVT within 3 cm of the saphenofemoral or saphenopopliteal junctions. Among the 192 patients diagnosed with SVT only, we observed 3-month thrombotic complications in 56 (29.2%; 95% CI, 23.2%-36.0%) patients, with a total of 69 events: 11 (5.7%) DVTs, 2 (1.0%) pulmonary embolisms, 37 (19.2%) SVT extensions, and 19 (9.8%) SVT recurrences. Eighty-two percent (9/11) of the 3-month DVT and pulmonary embolism events occurred in patients who initially received conservative management. Therapeutic treatment doses were most effective. ConclusionAt the time of SVT diagnosis, many patients had asymptomatic DVT and SVT near the deep venous system, supporting the systematic use of initial US in patients clinically diagnosed with SVT. The observed differences in 3-month complication rates, according to the treatment provided, highlight the need for large-scale randomized controlled trials to establish optimal management.

Single-center experience with the ClotTriever BOLD catheter for deep vein thrombosis percutaneous mechanical thrombectomy of the lower extremity.

The ClotTriever System is a percutaneous mechanical thrombectomy system used to treat deep vein thrombosis (DVT). The BOLD catheter is a newer compatible component with a modified coring element for which reported outcomes are limited. This retrospective study aims to assess the preliminary procedural safety and success data for patients treated with the BOLD catheter. All consecutive patients with symptomatic lower extremity DVT who underwent thrombectomy with the BOLD catheter between 23 November 2021 and 26 June 2022 at a single center were included. Baseline and procedural characteristics were reported. The primary outcome, intraprocedural safety, was assessed by a chart review of recorded intraprocedural adverse events (AEs) or device malfunction. The secondary outcome, procedural success, was defined as ≥75% reduction in the total occlusion across treated venous segments. This was assessed by an interventionalist review of pre- and postprocedural venograms. Additional outcomes included length of postprocedural hospital stay and assessment of AEs at discharge and a 30-day follow-up visit. Eleven patient cases were reviewed. The median patient age was 65 years, the majority were women, and all were treated unilaterally. All procedures were completed in a single session without intraprocedural AEs or device malfunction. The median procedural blood loss was 50 ml. A review of pre- and postprocedural venograms showed that 35 venous segments were treated, including the femoral (n = 9), common femoral (n = 9), external iliac (n = 10), and common iliac (n = 7) veins. Procedural success was achieved in 10 patients (90.9%), and the median reduction rate in venous occlusion was 100%. The median length of postprocedural hospital stay was 1 day, and no AEs were noted at discharge (N = 11). One adverse event occurred among the eight patients who completed their follow-up visit. A patient with advanced-stage cancer and medication failure had a recurrent DVT 13 days postprocedure, which was not related to the device or procedure. No safety concerns concerning the BOLD catheter were raised during the review of the cases included in this analysis, and the device was successful in reducing venous occlusion in patients with symptomatic proximal lower extremity DVT.

Dynamic Modelling for Cancer-Associated Venous Thromboembolism

Background: Cancer-associated venous thromboembolism (VTE) is an important source of morbidity and mortality. Current risk prediction models for thrombosis are handicapped by static applicability (i.e. one-time evaluation prior to the first cycle of chemotherapy). We hypothesized that event forecasting using time series modelling could account for important changes in clinical state, variations in treatment and aspects of cancer progression over time. Methods: The cohort consisted of adult patients with a solid tumor enrolled in the MSK-IMPACT study between 2014 and 2019. VTE was defined as any symptomatic or asymptomatic pulmonary embolus or lower extremity deep vein thrombosis. We derived time series mixed-effects logistic regression models in order to predict cancer-associated VTE events using baseline patient characteristics (cancer type, time from diagnosis and age) along with time-dependent covariates including total white blood cell count, hemoglobin, platelet count, albumin, creatinine and parenteral chemotherapy type. Time-periods of one month were used and models were fitted to predict the presence or absence of a VTE episode in the following period (time = t+1) based on predictor values in the current period (time = t). The laboratory test result ascribed to a given period could be either the last value in the interval or the mean of all interval-specific values (both approaches tested). Missing laboratory results were imputed using the previously known value when available. Differences in laboratory values between periods t-1 and t were included as predictors in the initial model along with indicators of missingness (see Figure for flow of information between time-period cells). We hypothesized that absence of laboratory testing for a time-period would be a marker of stable medical state and hence associated with a lower risk of VTE. A previously defined training set comprising 80% of the cohort was used and different modelling approaches were evaluated using 5-fold cross-validation. The final selected model was evaluated in a separate dedicated validation set including the remaining 20% of the cohort. Results: The original cohort included 35,391 patients, from which 26,075 individuals with no cancer-associated VTE episode before observation start and sufficient laboratory test information could be included in the analysis, comprising 276,579 months of observation and 1,463 VTE events. The initial logistic regression model including all available predictors was fitted on the training set, revealing associations between predictors and VTE risk largely consistent with data reported by other groups (see Table). After adjusting for multiple comparisons, significant predictors of cancer-associated VTE identified included albumin, cell count result missingness (decreased risk for missing value), treatment with a platinum analogue (increased risk), hemoglobin, white blood cell count, breast cancer (decreased risk) and high-grade glioma (increased risk). Based on model metrics and prior knowledge from published literature, the set of covariates selected for inclusion in the final model consisted of cell counts along with the corresponding missingness indicator, platelet count change over time, albumin and chemotherapy types. The c-index for the final model using 5-fold cross-validation in the training set was 0.77 (95% CI = 0.75-0.80), compared to 0.77 (95% CI = 0.74-0.79) in the validation set. The latter corresponded to a specificity of 0.83 (95% CI = 0.79-0.86) when fixing sensitivity at 50%. Conclusions: A simple mixed-effects logistic regression time series model demonstrated promising potential to estimate the risk of cancer-associated VTE on a dynamic basis using routine laboratory test results and chemotherapy prescription data widely available in most electronic health record systems. Validation of this dynamic VTE risk model has the potential to optimize outpatient thromboprophylaxis during periods of high thrombotic risk.

A Case Report of Korean Medicine Treatment on Clinical Symptoms in a Patient with Post-stroke Deep Vein Thrombosis

This case report shows the effect of Korean medicine treatment in a patient with deep vein thrombosis (DVT) after cerebral infarction who is suspected of having post-thrombotic syndrome (PTS) due to the loss of thrombus after receiving new oral anticoagulant (NOAC) treatment. The patient was treated with Korean medicine (<i>Boyanghwano-tang</i> and <i>Hyulbuchuko-tang</i>) three times a day. Acupuncture, moxibustion, infrared, and extra-physical therapy were given to the patient for 24 days. Clinical assessment - grading of edema and circumference of the left lower extremity were observed twice a week until the end of the treatment. NOAC treatment was continued for 24 days. After treatment, the patient’s edema grade and circumference of the extremity improved. On the 24th day, the patient’s chief complaints improved, and she requested termination of treatment. The results suggest that Korean medicine treatments, including <i>Boyanghwano-tang</i>, <i>Hyulbuchuko-tang</i>, and acupuncture therapy, can be effective in improving the clinical symptoms of DVT and PTS.

Coagulation-monitored, dose-adjusted catheter-directed thrombolysis or pharmaco-mechanical thrombus removal in deep vein thrombosis.

Background: Pharmaco-mechanical thrombectomy (PMT) and catheter-directed thrombolysis (CDT) are therapeutic options for selected patients with acute deep vein thrombosis (DVT) to prevent post-thrombotic syndrome (PTS). Patients and methods: We aimed to describe the clinical characteristics and outcomes of 159 patients with symptomatic iliofemoral DVT undergoing PMT alone, CDT alone, or CDT followed by PMT (bail-out) in the Swiss Venous Stent Registry. The primary outcome was the incidence of peri-interventional major and minor bleeding complications (ISTH criteria). Secondary outcomes included the incidence of PTS and stent patency after 3 years. Results: Mean age was 49±20 years and 58% were women. DVT involved the iliac veins in 99% of patients, whereas 53% had an underlying iliac vein compression. PMT alone was used in 40 patients, CDT alone in 77, and 42 received initial CDT followed by bail-out PMT due to insufficient thrombus clearance. Single-session PMT was the preferred approach in patients with iliac vein compression, patent popliteal vein, and absence of IVC thrombus. Patients treated with PMT alone received a lower r-tPA dose (median 10 mg, IQR 10-10) vs. those treated with CDT (20 mg, IQR 10-30). The rate of peri-interventional major bleeding was 0%, 1%, and 2%, whereas that of minor bleeding was 0%, 1%, and 12%, respectively, all occurring during CDT. After 3 years, PTS occurred in 6%, 9%, and 7% of patients, respectively. The primary stent patency rate was 95%, 88%, and 83%, respectively. Conclusions: The use of PMT and CDT for iliofemoral DVT was overall safe and resulted in high long-term patency and treatment success. Given the less severe presentation of DVT, single-session PMT appeared to be characterized by numerically better primary patency and lower perioperative bleeding event rates than CDT.

Percutaneous treatment of symptomatic deep vein thrombosis in adolescents using large-bore thrombectomy systems.

While large-bore mechanical thrombectomy provides effective venous thrombus removal, often with avoidance of thrombolytics, literature surrounding the application of these devices in pediatric patients is sparse. To report technical success and outcomes following large-bore thrombectomy systems in adolescent patients with deep venous thrombosis. A retrospective review identified all patients less than 18years of age undergoing mechanical venous thrombectomy at a single institution between 2018 and 2022. No patients were excluded. Technical success was defined as extraction of thrombus sufficient to restore unimpeded flow in affected segments. Clinical success was defined as resolution of presenting symptoms. Nine consecutive patients (6 females, 3 males; age range 15-17years) underwent 10 thrombectomy procedures using ClotTriever (n=6; 60%), FlowTriever (n=2; 20%), or both (n=2; 20%). Chronicity of thrombus was categorized as acute (<2weeks) in 6 (60%), subacute (2-6weeks) in 1 (10%), and chronic (>6weeks) in 3 (30%). Distribution of thrombus was lower extremity and/or inferior vena cava (IVC) in 9 (90%) and unilateral axillo-subclavian in 1 (10%). Technical success was achieved in 9 interventions (90%). Clinical success was achieved in 8 patients (88.9%). No patients received thrombolytics. There were no intraprocedural adverse events (AE). Minor complications (Society of Interventional Radiology mild adverse events) were observed in a delayed fashion following 2 interventions (20%). This preliminary experience demonstrated high rates of technical and clinical success with large-bore deep venous thrombectomy in adolescent patients across a range of thrombus chronicity and locations.

Incidence of deep vein thrombosis and symptomatic pulmonary embolism in Taiwanese patients with pelvic and/or acetabular fractures: a retrospective study

Venous thromboembolism (VTE) is common in patients with trauma, and thromboprophylaxis has been advocated. However, conflicting results regarding VTE rates in the Asian population following orthopaedic procedures have been presented. We aimed to investigate the VTE incidence in Taiwanese patients with pelvic and/or acetabular fractures and identify the associated risk factors. We included 402 patients who underwent surgery for pelvic and/or acetabular fractures. All patients received mechanical thromboprophylaxis with graduated compression stockings. Duplex scanning was performed postoperatively or during follow-up when signs or symptoms of deep vein thrombosis (DVT) developed. Variables with a significance level of ≤ 0.1 in the univariate analyses were introduced into the multivariate logistic regression analysis to identify DVT risk factors. The overall DVT and symptomatic pulmonary embolism (PE) rate was 3.48% (14/402 patients). Among patients with DVT, 46.1% were asymptomatic. Patients with VTE were significantly older than those without. Multivariate logistic regression analysis revealed that age was a VTE risk factor. The incidence of DVT and symptomatic PE in our cohort was low. Advanced age was a risk factor for VTE. These findings could help clinicians develop appropriate prevention and treatment strategies for VTE in Taiwanese patients with pelvic and/or acetabular fractures.

542 Prolonged VTE Prophylaxis Post Abdominal Cancer Surgery: Is It Necessary?

Abstract Aim NICE guidance currently recommends extending venous thromboembolism (VTE) prophylaxis to 28 days for patients who have undergone major cancer surgery in the abdomen. Literature highlights controversy around the efficacy of prolonged treatment preventing deep vein thrombosis (DVT) and pulmonary embolism (PE) and potential areas for improvement. Method Retrospective study of urology and colorectal cancer patients undergoing surgery between October 2020 and September 2022. Electronic patient notes were used to determine adherence to guideline and prevalence of PE and/or DVT in post-operative patients. Comparison was made between both cohorts. Results Patient cohort n = 802, colorectal n = 345 and urology n = 457. Average age 66.6±10.4. M:F ratio = 543:258. Colorectal cohort 20.9%(n = 71) received extended prophylaxis, 79.1%(n = 269) did not, of which 19.7%(n = 53) prophylaxis was contraindicated. 5 excluded as died or an inpatient. Urology cohort 53.4%(n = 244) received extended prophylaxis, 46.6%(n = 213) did not, of which 28.2%(n = 60) prophylaxis was contraindicated. Overall, 39.5%(n = 315) received extended prophylaxis vs 60.5%(n = 482) did not. n = 4 developed PE/DVT. Of which, n = 1 on extended prophylaxis and n = 3 not, Chi-squared 0.35, P value = 0.55. Conclusions Very few patients developed symptomatic PE and/or DVT despite a significant proportion of patients not receiving extended prophylaxis. No significant difference in symptomatic PE or DVT in patients with extended prophylaxis vs patients without. Prolonged administration of low molecular weight heparin as anticoagulation has repercussions such as cost and patients’ ability to self-administer which may subsequently require community support or a longer hospital stay. Therefore, a more targeted approach to extended VTE should be explored.