Risk factors for deep vein thrombosis after orthopedic surgery and the diagnostic value of D-dimer

Diagnostic value of D-dimer for lower extremity deep venous thrombosis caused by rib fracture: a retrospective study

OBJECTIVE

This study aimed to investigate the role of D-dimer in the diagnosis of lower extremity deep venous thrombosis (DVT) in patients with rib fractures.

METHOD

Retrospective analysis was conducted on the clinical data of 499 patients with rib fractures who were admitted to the Third Hospital of Shijiazhuang between October 2020 and September 2021. These patients were divided into the DVT and the non-DVT groups. D-dimer levels were compared between the two groups at 24, 48, and 72 h after the injury. Receiver operating characteristic curves were utilized to evaluate the diagnostic efficacy of dynamically monitoring changes in D-dimer for DVT.

RESULTS

The D-dimer levels in the DVT group were significantly higher than those in the non-DVT group at 24, 48, and 72 h after the injury. The area under the curve values for predicting DVT based on D-dimer level at 24, 48, and 72 h after injury in patients with rib fractures were 0.788, 0.605, and 0.568, respectively.

CONCLUSION

Detecting D-dimer levels 24 h after the injury can enhance diagnostic efficacy and sensitivity for DVT, thereby reducing the rate of missed diagnoses, which is of great clinical value.

Development and validation of a newly developed nomogram for predicting the risk of deep vein thrombosis after surgery for lower limb fractures in elderly patients

Background

Prevention of deep vein thrombosis (DVT) is indispensable in the treatment of lower limb fractures during the perioperative period. This study aimed to develop and validate a novel model for predicting the risk of DVT in elderly patients after orthopedic surgeries for lower limb fractures.

Methods

This observational study included 576 elderly patients with lower limb fractures who were surgically treated from January 2016 to December 2018. Eleven items affecting DVT were optimized by least absolute shrinkage and selection operator regression analysis. Multivariable logistic regression analysis was performed to construct a predictive model incorporating the selected features. C-index was applied to evaluate the discrimination. Decision curve analysis was employed to determine the clinical effectiveness of this model and calibration plot was applied to evaluate the calibration of this nomogram. The internal validation of this model was assessed by bootstrapping validation.

Results

Predictive factors that affected the rate of DVT in this model included smoking, time from injury to surgery, operation time, blood transfusion, hip replacement arthroplasty, and D-dimer level after operation. The nomogram showed significant discrimination with a C-index of 0.919 (95% confidence interval: 0.893-0.946) and good calibration. Acceptable C-index value could still be reached in the interval validation. Decision curve analysis indicated that the DVT risk nomogram was useful within all possibility threshold.

Conclusion

This newly developed nomogram could be used to predict the risk of DVT in elderly patients with lower limb fractures during the perioperative period.

Postoperative D-dimer levels predict venous thromboembolisms detected with contrast-enhanced computerized tomography in patients undergoing anterior cruciate ligament reconstruction

BACKGROUND

In the literature, factors associated with postoperative venous thromboembolisms (VTEs) after anterior cruciate ligament reconstruction (ACLR) are limited. This study aimed to investigate the incidence of venous thromboembolisms (VTEs) after anterior cruciate ligament reconstruction (ACLR) and to identify risk and predictive factors for VTEs.

METHODS

This retrospective study included 136 patients who underwent arthroscopic ACLR with mechanical prophylaxis between April 2012 and July 2022. Contrast-enhanced computed tomography (CT) was applied to detect VTEs comprising deep venous thromboses and pulmonary embolisms 7 days after surgery. Data including age, sex, body mass index, concomitant treatments, graft types, smoking status, operative and tourniquet times, postoperative D-dimer levels, and other laboratory test results, were collected for analyses. The incidence of radiographically confirmed VTEs and the associated risk factors, such as age, sex, body mass index, concomitant treatments, graft types, smoking status, operative and tourniquet times, postoperative D-dimer levels, and other laboratory test results, were analyzed.

RESULTS

The overall incidence of radiographic VTEs was 11.0% (15 cases) in 136 patients. There was one symptomatic patient who had Homan's sign. Multivariable analysis indicated that postoperative D-dimer level was an independent factor related to a radiographic VTE after ACLR, although there was no association between radiographic VTEs and preoperative status or operation status. The optimal cutoff value for postoperative D-dimer level was 2.8 μg/ml according to the receiver operating characteristic curve analysis, with a sensitivity of 80.0% and specificity of 83.5%.

CONCLUSION

The incidence of ACLR-associated radiographical VTEs (deep venous thrombosis and pulmonary embolism) under mechanical prophylaxis was 11.0% in this study. An elevated D-dimer level at 7 days after surgery is an independent predictor of VTE in patients undergoing ACLR. The postoperative D-dimer level is a more reliable marker for identifying VTE in patients who underwent ACLR.

The Impact of D-Dimer on Postoperative Deep Vein Thrombosis in Patients with Thoracolumbar Fracture Caused by High-Energy Injuries

Objective

To investigate the dynamic variation of D-dimer and to evaluate the efficacy and accuracy of D-dimer level in patients with thoracolumbar fractures caused by high-energy injuries.

Methods

A total of 121 patients with thoracolumbar fractures caused by high-energy injuries were retrospectively identified and included in this study. There were 83 males and 38 females, with an average age of 48.6 ± 11.2 years. All patients were treated with either screw fixation surgery or decompression fixation surgery. The D-dimer levels were measured 1 day before surgery and on the first, third, and fifth days after surgery. The dynamic variation of D-dimer and the effects of risk factors on D-dimer levels were analysed. A receiver operating characteristic (ROC) curve analysis was performed and the appropriate D-dimer cut-off level was determined for deep vein thrombosis (DVT) screening.

Results

Due to a trough on the third day, D-dimer levels grew in an unsustainable manner following surgery (P < 0.001). Patients with the operation time >120 min (P = 0.009) and those with an American Spinal Injury Association (ASIA) score A-C (P < 0.001) had higher D-dimer levels. The area under the curve of D-dimer was the greatest on the third day. Applying stratified cut-off values did not change the sensitivity, specificity and negative predictive value in the group with an operation time >120 min, and ASIA score A-C group.

Conclusions

D-dimer levels elevated with fluctuation in patients with thoracolumbar fractures caused by high-energy injuries after surgery. Both operation time and ASIA score had an impact on D-dimer levels. Regarding DVT diagnoses, the diagnostic value of D-dimer was highest on the third day postoperatively, and stratified cut-off values by these two factors did not show better diagnostic efficacy compared with a collective one.

D-Dimer Levels Are Not Elevated in SARS-CoV-2 IgG Positive Patients Undergoing Elective Orthopedic Surgery

INTRODUCTION

In acute COVID-19, D-Dimer levels can be elevated and those patients are at risk for thromboembolic events. This study aims to investigate differences in preoperative D-Dimer levels in SARS-CoV-2 IgG positive and negative patients undergoing primary total knee and total hip replacement (TJA) or spine surgery.

METHODS

D-Dimer levels of 48 SARS-CoV-2 IgG positive and 718 SARS-CoV-2 IgG negative spine surgery patients were compared to those of 249 SARS-CoV-2 IgG positive and 2102 SARS-CoV-2 IgG negative TJA patients. Patients were assigned into groups based on D-Dimer levels as follows: <200 ng/mL, 200-400 ng/mL, and >400 ng/mL D-Dimer Units (DDU).

RESULTS

D-Dimer levels did neither differ significantly between SARS-CoV-2 IgG positive spine surgery patients and TJA patients (p = 0.1), nor between SARS-CoV-2 IgG negative spine surgery and TJA patients (p = 0.7). In addition, there was no difference between SARS-CoV-2 IgG positive and negative spine surgery patients and SARS-CoV-2 IgG positive and negative TJA patients (p = 0.3).

CONCLUSIONS

There is no difference in D-Dimer levels between SARS-CoV-2 IgG positive and negative patients and there does not seem to be any difference for different orthopedic specialty patients. Routine testing of D-Dimer levels is not recommended for patients undergoing elective orthopedic surgery.

Time Course of Inflammatory and Procoagulant Markers in the Early Period After Total Hip Replacement

Our study aimed to investigate the levels and time-course of systemic inflammatory and hemostasis markers in the early postoperative period in patients undergoing total hip replacement (THR). The study included 70 patients of both sexes, average age 68.4 ± 10.9 years. Levels of inflammatory and hemostasis markers were measured before surgery (POD 0), a day after the surgery (POD 1) and 5 days after surgery (POD 5). In the postoperative period inflammatory markers increased. The operation provoked a significant increase of CRP on POD 1 in comparison to POD 0 (68.5 ± 5.4 vs 6.8 ± 2.2 μg/mL, p < 0.001) and the additional increase was registered on POD 5 (87.5 ± 8.1 vs 68.5 ± 5.4 μg/mL, p < 0.001). Interleukin-6 significantly increased on POD 1 (251.5 ± 21.6 vs 14.6 ± 7.1 μg/mL, p < 0.001) and after that (POD 5) decreased. After surgery leukocyte count, neutrophil/lymphocyte ratio and platelet/lymphocyte ratio were significantly higher compared to POD 0. Activation of coagulation in the postoperative period was shown by increased peak thrombin on POD 5 in comparison to POD 0 (185 ± 27 vs. 124 ± 31 nM, p < 0.001). D-dimer was increased on POD 1 and an additional rise was observed on POD 5. vWF also progressively increased in the observed period. Results of our study showed that after THR systemic inflammatory markers increased and coagulation function was enhanced. Determination of inflammatory and procoagulant markers could help identify patients at risk for cardiovascular thromboembolic events.

Analysis of perioperative risk factors for deep vein thrombosis in patients with femoral and pelvic fractures

Objective

Clinical characteristics, anticoagulant protocols, and risk factors of deep vein thrombosis (DVT) in patients with femoral and pelvic fractures were analyzed throughout the perioperative period to provide references for early identification and optimization of risk factors.

Methods

This was a retrospective study. A total of 569 patients undergoing surgery of femoral and pelvic fractures from May 2018 to December 2019 were included.

The clinical data including general conditions, trauma, surgery, anticoagulant protocols, and laboratory indexes were collected. According to the results of deep vein Doppler ultrasonography of the lower extremities, the patients were divided into non-DVT group and DVT group. Univariate analysis and multivariate logistic regression analysis were used to identify the independent risk factors of preoperative and postoperative DVT.

Results

The incidence of DVT was 40.25% and preoperative DVT was 26.71%, which was higher than the incidence of postoperative DVT of 17.22%. Most of them were thrombus on the affected side (60.26%) and distal thrombus (81.66%). The average time of DVT formation was 6.55 ± 0.47 days after trauma and 6.67 ± 0.48 days after surgery. Chronic obstructive pulmonary disease (COPD), anemia, hypoproteinemia, non-anticoagulation before surgery, delayed anticoagulation after trauma and admission, high-energy trauma, multiple injuries, drinking history, and advanced age were independent risk factors for perioperative DVT. The increased level of fibrinogen degradation products was an independent risk factor for preoperative DVT. These risk factors were identified to be independently associated with postoperative DVT, including intraoperative blood transfusion, postoperative blood transfusion, pulmonary infection, preoperative non-anticoagulation, postoperative delayed anticoagulation, preoperative waiting time > 7 days, operative time > 2 h, c-reactive protein, fibrinogen level, platelet count 1 day after surgery, c-reactive protein, fibrinogen, and hemoglobin levels 3 days after surgery, comminuted fracture.

Conclusions

At present, anticoagulation and other DVT prevention and treatment programs have not changed the current situation that the incidence of DVT is still high. Through the analysis of the risk factors of DVT throughout the perioperative period, optimizing the perioperative blood transfusion, preoperative lung disease, hypoproteinemia, anemia, inflammation, etc., and surgery as soon as possible after trauma may further reduce its incidence.

Meta-analysis of serum and/or plasma D-dimer in the diagnosis of periprosthetic joint infection

BACKGROUND

The purpose of this meta-analysis was to evaluate the diagnostic value of D-dimer in detecting periprosthetic joint infection (PJI).

METHODS

A systematic search and screening of relevant studies was performed in the databases PubMed, Web of Science, and Embase using the following medical subject headings (MeSH) or keywords: "arthroplasty or joint prosthesis or joint replacement or periprosthetic joint or prosthetic joint", "infection or infectious or infected", and "D-dimer or serum D-dimer or plasma D-dimer or fibrin degradation products". Data were subsequently analysed and processed using Meta-Disc.

RESULTS

Seven studies with 1285 patients were included in this meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.75 (95% confidence interval [CI] 0.70-0.79), 0.69 (95% CI 0.66-0.72), 3.01 (95% CI 1.84-4.93), 0.32 (95% CI 0.19-0.53), and 10.20 (95% CI 3.63-28.64), respectively. Subgroup analyses showed that the use of serum D-dimer had better sensitivity and specificity than plasma D-dimer for the diagnosis of PJI.

CONCLUSIONS

Serum D-dimer was shown to have a better diagnostic value than plasma D-dimer for the diagnosis of PJI. Further research is required for clarification.

Deep Vein Thrombosis in Patients with Intertrochanteric Fracture: A Retrospective Study

BACKGROUND

This study aimed to investigate the incidences of pre- and post-operative lower extremity deep venous thrombosis (DVT) in hospitalized patients with intertrochanteric fractures and to analyze the relevant risk factors.

METHODS

A retrospective study was conducted between July 2014 and October 2016 in 218 intertrochanteric fracture patients who presented at Xi'an Honghui Hospital and underwent Doppler ultrasonography for DVT diagnosis. We divided DVT into distal, proximal, and mixed thrombosis. Patients were divided into either the thrombosis or no thrombosis group according to preoperative and postoperative ultrasonography results. All patients were evaluated for the risk factors associated with thrombosis.

RESULTS

A total of 37.61% of preoperative patients had DVT, and the postoperative incidence increased to 58.72%. The days between fracture and hospitalization and the days between fracture and surgery were independent risk factors for preoperative DVT. The days between fracture and hospitalization and d-dimer levels at postoperative 1 day were independent risk factors of postoperative DVT. In total 23.4% of the patients progressed from having no thrombosis preoperatively to having distal, proximal, or mixed DVT postoperatively (22.02%, 0.46%, and 0.92%, respectively). Distal DVT constituted 86.59% and 90.63% of all preoperative and postoperative DVTs, respectively.

CONCLUSION

Intertrochanteric fracture is a common type of hip fracture in the elderly, and the incidence of DVT after intertrochanteric fracture may be underestimated. Early intervention (early admission and early surgery) might reduce the incidence of DVT.

Different strategies for pharmacological thromboprophylaxis for lower-limb immobilisation after injury: systematic review and economic evaluation

BACKGROUND

Thromboprophylaxis can reduce the risk of venous thromboembolism (VTE) during lower-limb immobilisation, but it is unclear whether or not this translates into meaningful health benefit, justifies the risk of bleeding or is cost-effective. Risk assessment models (RAMs) could select higher-risk individuals for thromboprophylaxis.

OBJECTIVES

To determine the clinical effectiveness and cost-effectiveness of different strategies for providing thromboprophylaxis to people with lower-limb immobilisation caused by injury and to identify priorities for future research.

DATA SOURCES

Ten electronic databases and research registers (MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Database of Abstracts of Review of Effects, the Cochrane Central Register of Controlled Trials, Health Technology Assessment database, NHS Economic Evaluation Database, Science Citation Index Expanded, ClinicalTrials.gov and the International Clinical Trials Registry Platform) were searched from inception to May 2017, and this was supplemented by hand-searching reference lists and contacting experts in the field.

REVIEW METHODS

Systematic reviews were undertaken to determine the effectiveness of pharmacological thromboprophylaxis in lower-limb immobilisation and to identify any study of risk factors or RAMs for VTE in lower-limb immobilisation. Study quality was assessed using appropriate tools. A network meta-analysis was undertaken for each outcome in the effectiveness review and the results of risk-prediction studies were presented descriptively. A modified Delphi survey was undertaken to identify risk predictors supported by expert consensus. Decision-analytic modelling was used to estimate the incremental cost per quality-adjusted life-year (QALY) gained of different thromboprophylaxis strategies from the perspectives of the NHS and Personal Social Services.

RESULTS

Data from 6857 participants across 13 trials were included in the meta-analysis. Thromboprophylaxis with low-molecular-weight heparin reduced the risk of any VTE [odds ratio (OR) 0.52, 95% credible interval (CrI) 0.37 to 0.71], clinically detected deep-vein thrombosis (DVT) (OR 0.40, 95% CrI 0.12 to 0.99) and pulmonary embolism (PE) (OR 0.17, 95% CrI 0.01 to 0.88). Thromboprophylaxis with fondaparinux (Arixtra®, Aspen Pharma Trading Ltd, Dublin, Ireland) reduced the risk of any VTE (OR 0.13, 95% CrI 0.05 to 0.30) and clinically detected DVT (OR 0.10, 95% CrI 0.01 to 0.94), but the effect on PE was inconclusive (OR 0.47, 95% CrI 0.01 to 9.54). Estimates of the risk of major bleeding with thromboprophylaxis were inconclusive owing to the small numbers of events. Fifteen studies of risk factors were identified, but only age (ORs 1.05 to 3.48), and injury type were consistently associated with VTE. Six studies of RAMs were identified, but only two reported prognostic accuracy data for VTE, based on small numbers of patients. Expert consensus was achieved for 13 risk predictors in lower-limb immobilisation due to injury. Modelling showed that thromboprophylaxis for all is effective (0.015 QALY gain, 95% CrI 0.004 to 0.029 QALYs) with a cost-effectiveness of £13,524 per QALY, compared with thromboprophylaxis for none. If risk-based strategies are included, it is potentially more cost-effective to limit thromboprophylaxis to patients with a Leiden thrombosis risk in plaster (cast) [L-TRiP(cast)] score of ≥ 9 (£20,000 per QALY threshold) or ≥ 8 (£30,000 per QALY threshold). An optimal threshold on the L-TRiP(cast) receiver operating characteristic curve would have sensitivity of 84-89% and specificity of 46-55%.

LIMITATIONS

Estimates of RAM prognostic accuracy are based on weak evidence. People at risk of bleeding were excluded from trials and, by implication, from modelling.

CONCLUSIONS

Thromboprophylaxis for lower-limb immobilisation due to injury is clinically effective and cost-effective compared with no thromboprophylaxis. Risk-based thromboprophylaxis is potentially optimal but the prognostic accuracy of existing RAMs is uncertain.

FUTURE WORK

Research is required to determine whether or not an appropriate RAM can accurately select higher-risk patients for thromboprophylaxis.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017058688.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Nonoperative Management Prior to Hip Arthroscopy for Femoroacetabular Impingement Syndrome: An Investigation Into the Utilization and Content of Physical Therapy

BACKGROUND

There has been a significant increase in surgeries for femoroacetabular impingement syndrome in recent years, but little is known about the use of physical therapy prior to surgery.

OBJECTIVES

To investigate the use of physical therapy prior to hip arthroscopy for femoroacetabular impingement syndrome, by assessing the number of visits and use of exercise. A secondary objective was to evaluate whether comorbidities prior to surgery were associated with the use of physical therapy.

METHODS

In this retrospective observational cohort study, eligible participants between the ages of 18 and 50 years undergoing hip arthroscopy between 2004 and 2013 in the Military Health System were included. Patients were categorized based on whether they saw a physical therapist for their hip in the year prior to surgery. For physical therapy patients, dosing variables were identified, including total number of visits and visits that included an exercise therapy procedure code.

RESULTS

Of 1870 participants, 1106 (59.1%) did not see a physical therapist for their hip prior to surgery. For those who did, the median number of visits was 2. Only 220 (11.8%) had 6 or more unique visits with an exercise therapy procedure code. Exercise was coded in 43.4% to 63.0% of the total visits in each individual course of care (mean, 52.3%). There was an association between substance abuse and exercise utilization. No other comorbidities were associated with physical therapy or exercise therapy utilization.

CONCLUSION

Physical therapy was not commonly used before undergoing arthroscopic hip surgery by patients seeking care in the Military Health System. Further research is needed to understand the reasons for poor utilization and better define failed nonoperative management.

LEVEL OF EVIDENCE

Therapy, level 2b. J Orthop Sports Phys Ther 2019;49(8):593-600. Epub 15 May 2019. doi:10.2519/jospt.2019.8581.

Current status of venous thromboembolism development during the perioperative period for colorectal cancer, its prevention with enoxaparin, and monitoring methods

Background: There is a high incidence of venous thromboembolism (VTE) during the perioperative period for cancer. Therefore, there is an urgent need to elucidate the perioperative onset and appropriate prophylaxis for VTE. Purpose: VTE during the perioperative period for colorectal cancer was evaluated by lower limb venous ultrasonic examinations (lower limb echo) under enoxaparin prophylaxis. We also examined the relationship between hemorrhagic adverse events and anti-Xa factor activity. Patients and methods: Eighty-three subjects who underwent lower limb echo during the perioperative period for colorectal cancer were prospectively included. Enoxaparin was administered for 5 days, from day 1 to day 5 after surgery. Lower limb echo was performed before surgery and on day 5 after surgery. The activated partial thromboplastin time, D-dimer levels, and anti-Xa factor activity were measured before surgery and on days 1, 3, 5, 7, and 9 after surgery. Results: VTEs before surgery were observed on lower limb echo for 16 patients (19.2%). Three patients (3.6%) had a new thrombus during the perioperative period. The preoperative D-dimer level was an independent prognostic factor for newly formed postoperative VTEs (p=0.0036; odds ratio, 19.37). Three patients (3.6%) had hemorrhagic events; however, there was no significant trend for anti-Xa factor activity. Conclusion: VTE prevention using enoxaparin was relatively safe, and D-dimer measurements before surgery were useful for predicting perioperative VTE.

Plasma D-dimer is not useful in the prediction of deep vein thrombosis after total knee arthroplasty in patients using rivaroxaban for thromboprophylaxis

Background

Venous thromboembolism (VTE) is a serious complication following total joint replacement. The use of rivaroxaban, a highly selective and direct factor Xa inhibitor, has been used widely as a safe and efficacious way to prevent VTE after total joint replacements. However, little is known about the diagnostic efficacy of plasma D-dimer test on deep vein thrombosis (DVT) in patients using rivaroxaban for thromboprophylaxis. The study is aimed to investigate the trend and the diagnostic efficacy of D-dimer test on DVT in patients with primary total knee arthroplasty (TKA) using rivaroxaban for thromboprophylaxis.

Methods

Two hundred TKA patients using rivaroxaban postoperatively as chemical prophylaxis were reviewed. D-dimer levels were checked at 4 h after the surgery and on postoperative days 1 and 4. Venography was used to document the presence of DVT. The Mann-Whitney U test was used to detect the differences in the D-dimer levels at different time points in patients with and without DVT, followed by Bonferroni corrections for p values. Receiver operating characteristics (ROC) curves were constructed to determine the best cutoff values of the D-dimer test at each time point after the surgery.

Results

Twenty-nine of the 200 patients were found to have deep vein thrombosis by venography, resulting in an incidence of 14.5%. All patients with DVTs occurred in the distal calf veins, and only one patient was symptomatic. We found significant differences in D-dimer concentration between patients with and without DVT at postoperative day 4. The best cutoff value determined by receiver operating characteristics analysis was 3.8 mg/L at postoperative day 4, with an AUC equal to 63.5%, and a sensitivity, specificity, PPV, and NPV of 58.6, 76, 29.3, and 91.5%, respectively.

Conclusions

Rivaroxaban was effective on reducing DVT in patients undergoing TKA. Because all the DVTs occurred in the leg veins, decreased thrombus volume and size might result in poor accuracy of plasma D-dimer test in prediction or diagnosis of postoperative DVT.

Impact of prestorage leucoreduction of autologous whole blood on length of hospital stay with a subgroup analysis in bilateral hip arthroplasty

BACKGROUND

Although prestorage leucoreduction (LR) of blood components for transfusion has gained favour around the world, evidence of its beneficial clinical effects is ambiguous.

STUDY DESIGN AND METHODS

To reveal whether leucocytes and/or platelets in transfused blood are related to transfusion-related adverse effects, a prospective randomized crossover study was performed on patients who donated autologous blood prior to elective surgery. Among 1487 primary enrolees, a total of 192 patients undergoing two-stage, bilateral total hip arthroplasty were randomized to receive autologous blood that was either prestorage leucoreduced, or not, for the first procedure. For the second procedure, each patient was crossed over to receive alternatively processed autologous blood. Length of hospital stay served as a primary end-point, with perioperative infectious/thrombotic complications, pre- and postoperative laboratory values, and body temperature serving as secondary endpoints.

RESULTS

No significant differences emerged between prestorage LR and non-LR cohorts in length of hospital stay, as well as perioperative infectious/thrombotic complications, postoperative body temperature and duration of fever. Postoperative laboratory values including white blood cell counts and C-reactive protein levels had no significant differences.

CONCLUSION

This study could not prove any superiority of prestorage LR over non-LR for autologous whole blood among patients who underwent total hip arthroplasty.

Fibrin polymerization simulation using a reactive dissipative particle dynamics method

The study on the polymerization of fibrinogen molecules into fibrin monomers and eventually a stable, mechanically robust fibrin clot is a persistent and enduring topic in the field of thrombosis and hemostasis. Despite many research advances in fibrin polymerization, the change in the structure of fibrin clots and its influence on the formation of a fibrous protein network are still poorly understood. In this paper, we develop a new computational method to simulate fibrin clot polymerization using dissipative particle dynamics simulations. With an effective combination of reactive molecular dynamics formularies and many body dissipative particle dynamics principles, we constructed the reactive dissipative particle dynamics (RDPD) model to predict the complex network formation of fibrin clots and branching of the fibrin network. The 340 kDa fibrinogen molecule is converted into a spring-bead coarse-grain system with 11 beads using a topology representing network algorithm, and using RDPD, we simulated polymerization and formation of the fibrin clot. The final polymerized structure of the fibrin clot qualitatively agrees with experimental results from the literature, and to the best of our knowledge this is the first molecular-based study that simulates polymerization and structure of fibrin clots.

Appropriate Use of Venous Imaging and Analysis of the D-Dimer/Clinical Probability Testing Paradigm in the Diagnosis and Location of Deep Venous Thrombosis

BACKGROUND

The D-dimer (DD) level combined with the pretest Wells criteria probability (WCP) score can safely exclude deep venous thrombosis (DVT). The objective of this study was to examine the correlation between DD results alongside WCP score with findings on venous duplex ultrasound (VDU). The hypothesis is that VDU remains overutilized in low-risk patients with negative DD and that higher DD levels may correlate with thrombus burden and location.

METHODS

Patients who presented to a high-volume tertiary care center with lower limb swelling with or without associated pain were retrospectively examined through June and July for 4 consecutive years (2012 to 2015). After calculating WCP, patients were divided into low-, moderate-, and high-risk categories. Electronic DD results utilizing enzyme linked immunosorbent assay, WCP data, and VDU analysis data were merged and analyzed based on receiver operator characteristic curve to determine the DD cutoff point for each WCP. Abnormal DD with an average value ≥ 0.6 mg/L fibrinogen equivalent units (FEUs) was correlated to positive DVT to differentiate proximal DVT (above popliteal vein) from distal DVT (below popliteal vein).

RESULTS

Data of 1,909 patients were analyzed, and 239 (12.5%) patients were excluded secondary to serial repeat visits or follow-ups, surveillance screens, and if they had a previous history of DVT. The average age was 62.1 ± 16.3 years with more women (55.7%) and the majority presented with limb pain and edema (87%). DD studies were ordered and completed in 202 patients and correlated with all positive and negative DVT patients (100% sensitivity and negative predictive value, with specificity and positive predictive value of 14.9% and 15.9%, respectively). Twenty-six of 202 patients had DD that were in the normal range 0.1-0.59 mg/L (FEU), all of which were negative for DVT (100% sensitive). Fifty one of 202 patients had DD values of 0.6-1.2 mg/L FEU, of which only 3 DVTs were recorded, and all of them were distal DVTs. In addition, 685 patients with WCP <1 and negative DD were sent for VDU. Thus, 762 patients had an unnecessary immediate VDU (Wells ≤1 and -DD) study during their initial presentation. Potential charge savings for VDU for all patients are 762 × $1,557 = $1,186,434 and DD for all patients are 762 × $182 = $138,684, with total potential savings of $1,047,750 (USD 2016).

CONCLUSIONS

This study suggests that DD is still underutilized, and DD in conjunction with WCP could significantly reduce the number of unnecessary immediate VDUs. Higher value of DD (>1.2 mg/L FEU) may raise concern for proximal DVT. Concern on cost-effectiveness exists and raises the demand for a proposed algorithm to be followed.

possible role of soluble fibrin monomer complex after gastroenterological surgery

AIM

To examine the role of soluble fibrin monomer complex (SFMC) in the prediction of hypercoagulable state after gastroenterological surgery.

METHODS

We collected data on the clinical risk factors and fibrin-related makers from patients who underwent gastroenterological surgery at Hiroshima University Hospital between April 1, 2014 and March 31, 2015. We investigated the clinical significance of SFMC, which is known to reflect the early plasmatic activation of coagulation, in the view of these fibrin related markers.

RESULTS

A total of 123 patients were included in the present study. There were no patients with symptomatic VTE. Thirty-five (28%) patients received postoperative anticoagulant therapy. In the multivariate analysis, a high SFMC level on POD 1 was independently associated with D-dimer elevation on POD 7 (OR = 4.31, 95%CI: 1.10-18.30, P = 0.03). The cutoff SFMC level was 3.8 μg/mL (AUC = 0.78, sensitivity, 63%, specificity, 89%). The D-dimer level on POD 7 was significantly reduced in high-SFMC patients who received anticoagulant therapy in comparison to high-SFMC patients who did not.

CONCLUSION

The SFMC on POD 1 strongly predicted the hypercoagulable state after gastroenterological surgery than the clinical risk factors and the other fibrin related markers.

Clinical analysis of preoperative risk factors for the incidence of deep venous thromboembolism in patients undergoing posterior lumbar interbody fusion

Background

The purpose of this study aimed to assess preoperative risk factors for the incidence of deep venous thromboembolism in patients undergoing posterior lumbar interbody fusion (PLIF).

Methods

The diagnosis of preoperative deep vein thrombosis (DVT) was confirmed by Doppler ultrasonography. To examine the preoperative risk factors for DVT admitted for PLIF, comparative analysis of the DVT-positive and DVT-negative groups was done.

Results

DVT was detected in 9.4 % (269/2861) patients, including 17 proximal DVT patients (6.3 %) and 252 the distal DVT patients (93.7 %). According to multivariate logistic regression analysis, the age, preoperative D-dimer, and history of rheumatoid arthritis were significant risk factors relative to the onset of DVT after posterior lumbar surgery.

Conclusions

According to the result of our study, age, positive preoperative plasma D-dimer level, and rheumatoid arthritis had the influential impact on the incidence of DVT admitted for PLIF.

Diagnostic Value of Elevated D-Dimer Level in Venous Thromboembolism in Patients With Acute or Subacute Brain Lesions

Objective

To define the risk factors that influence the occurrence of venous thromboembolism (VTE) in patients with acute or subacute brain lesions and to determine the usefulness of D-dimer levels for VTE screening of these patients.

Methods

Medical data from January 2012 to December 2013 were retrospectively reviewed. Mean D-dimer levels in those with VTE versus those without VTE were compared. Factors associated with VTE were analyzed and the odds ratios (ORs) were calculated. The D-dimer cutoff value for patients with hemiplegia was defined using a receiver operating characteristic (ROC) curve.

Results

Of 117 patients with acute or subacute brain lesions, 65 patients with elevated D-dimer levels (mean, 5.1±5.8 mg/L; positive result >0.55 mg/L) were identified. Logistic regression analysis showed that the risk of VTE was 3.9 times higher in those with urinary tract infections (UTIs) (p=0.0255). The risk of VTE was 4.5 times higher in those who had recently undergone surgery (p=0.0151). Analysis of the ROC showed 3.95 mg/L to be the appropriate D-dimer cutoff value for screening for VTE (area under the curve [AUC], 0.63; 95% confidence interval [CI], 0.5-0.8) in patients with acute or subacute brain lesions. This differs greatly from the conventional D-dimer cutoff value of 0.55 mg/L. D-dimer levels less than 3.95 mg/L in the absence of surgery showed a negative predictive value of 95.8% (95% CI, 78.8-99.8).

Conclusion

Elevated D-dimer levels alone have some value in VTE diagnosis. However, the concomitant presence of UTI or a history of recent surgery significantly increased the risk of VTE in patients with acute or subacute brain lesions. Therefore, a different D-dimer cutoff value should be applied in these cases.