Deep Venous Thrombosis Formation Research Articles

Low-molecular-weight heparin calcium attenuates the tourniquet-induced ischemia-reperfusion injury in rats

Ischemia-reperfusion injury (IRI) is a common postoperative complication of the tourniquet used surgery; low-molecular-weight heparin calcium (LMWH) is frequently used postoperatively to prevent the formation of deep venous thrombosis. However, subcutaneous hemorrhage can usually be seen in patients who underwent lower limb surgery, especially in total knee arthroplasty, the influence of LMWH on IRI remains controversial. In this experiment, we designed an animal model to observe the influence of LMWH on the skeletal muscle injury induced by tourniquets. Sprague-Dawley (SD) rats underwent either 2 h of unilateral hindlimb ischemia or anesthesia alone, at different time points of reperfusion interval, animals received either 4mg/kg LMWH or normal saline subcutaneously twice a day. The levels of inflammatory markers in serum, the expression of apoptosis proteins, as well as histological examination of skeletal muscles, were detected at 48-h reperfusion. We found that the injury of skeletal muscle and the systemic inflammatory response was less severe in LMWH-treated animals, indicating that LMWH could attenuate the tourniquet-induced IRI. In conclusion, LMWH given postoperatively after limb surgery may be clinically beneficial.

Correlation Between the Fracture Line Plane and Perioperative Deep Vein Thrombosis in Patients with Tibial Fracture

ObjectiveTo explore the correlation between the fracture line inferior plane and perioperative deep venous thrombosis (DVT) in patients with tibial fractures.MethodsData was collected from the medical records of 536 consecutive patients with tibial fractures at Xi’an Honghui Hospital. The patients were divided into distal, shaft, and proximal segment groups according to the fracture line inferior plane on radiographs. Multivariate logistic regression models were used to identify the role of the inferior plane of the fracture line in perioperative DVT.ResultsA total of 431 patients were included in the study and 226 patients had perioperative DVT in the lower extremities, including 11 proximal and 215 distal DVTs. Univariate regression analysis showed a significant correlation between the proximal segment and perioperative DVT; however, no correlation was found in the shaft segment group. Additionally, age, coronary heart disease, associated injuries, and time to operation ≥6 days were risk factors for perioperative DVT. However, fixation with intramedullary nails may be a protective factor for perioperative DVT compared with plates. After adjusting for potential confounding factors, the proximal segment group had an increased incidence of perioperative DVT compared to the distal segment group.ConclusionsThe proximal segment may be correlated with an increased incidence of perioperative DVT by 7.30-fold in patients with tibial fractures compared to that in the distal segment. In clinical practice, surgeons should be vigilant for DVT formation in these patients.

Identification of thrombomodulin as a dynamic monitoring biomarker for deep venous thrombosis evolution.

It has been demonstrated that thrombomodulin (TM) serves an important role in the formation of deep venous thrombosis (DVT) and is regarded to be a marker that can be used to measure vascular endothelial cell damage. However, how TM levels change during DVT evolution has not yet been well understood. The current study aimed to investigate the dynamic changes of TM during the evolution of DVT and explore the possible mechanisms behind these. A total of 48 patients newly diagnosed with DVT and 23 matched healthy controls were enrolled in the present study, and their plasma TM levels were examined and compared. In addition, a DVT model was established using Sprague-Dawley rats via the ‘stenosis’ method. The thrombi size, histopathologic changes and expression of TM and NF-κB in plasma and venous endothelium were measured at 9 different time points (1, 4, 6, 12 and 24 h, and at 3, 7, 14 and 21 days). Finally, the effect of inhibiting the activation of NF-κB on TM was investigated using pyrrolidine dithiocarbamate (PDTC), which is a potent inhibitor of the NF-κB pathway. The results of the current study indicated that the mean level of plasma TM in patients with DVT was significantly increased compared with healthy controls. In addition, thrombi size (clot length and weight), TM and NF-κB expression in the animal model plasma exhibited three distinct periods (1-12, 24 h-day 7 and 14-21) of markedly different results between periods. Immunofluorescence results confirmed the co-localization of TM and NF-κB in endothelial cells. In addition, it was indicated that the expression of TM in the endothelium of DVT models was upregulated compared with the control, while NF-κB was significantly downregulated. Following the administration of PDTC, the level of NF-κB and TM in the plasma were decreased significantly dose-dependently. The results of the current study suggested that TM was involved in the evolution of DVT and may be used as a dynamic biomarker to measure disease activity. Furthermore, the expression of TM during the evolution of DVT was indicated to be associated with the NF-κB signaling pathway.

Combined use of intravenous and topical tranexamic acid efficiently reduces blood loss in patients aged over 60 operated with a 2-level lumbar fusion

PurposeThe current study was conducted to assess the efficacy and safety of the intravenous (IV) administration combined with topical administration of tranexamic acid (TXA)in patients (aged over 60) scheduled for a 2-level lumbar fusion surgery.MethodsTwo hundred eighty patients scheduled for a 2-level lumbar fusion surgery were randomized into four groups, including an IV group, a local group, a combined group, and a control group. Patients in the combined group, in the IV group, in the topical group, and in the control group were administrated with 15 mg/kg of IV-TXA + 2 g TXA in local, 15 mg/kg IV-TXA, 2 g TXA in local, and 100 ml IV, respectively. The results of total blood loss (TBL), maximum hemoglobin drop, the transfusion rate, and the number of allogeneic blood units were compared. Deep venous thrombosis (DVT) and pulmonary embolism (PE) events were monitored and recorded.ResultsThe TBL was 635.49 ± 143.60, 892.62 ± 166.85, 901.11 ± 186.25, and 1225.11 ± 186.25 mL for the combined group, the IV group, the topical group, and the control group, respectively (p = 0.015, p = 0.001, respectively). The average maximum hemoglobin drop in the four above groups was 2.18 ± 0.24, 2.80 ± 0.37, 2.40 ± 0.64, and 3.40 ± 1.32 g/dL, respectively. No PE event was reported during the follow-up. Although asymptomatic DVT events were reported by 1, 2, and 2 patients in the combined group, topical group, and control group, respectively, there is no intergroup difference.ConclusionsThe combined use of TXA effectively reduced the total blood loss and blood transfusion rate in patients aged over 60 scheduled for a 2-level lumbar fusion, without increasing the incidence of DVT and PE formation.

Analysis of risk factors associated with deep venous thrombosis in orthopedic inpatients

Objective To explore the risk factors of deep venous thrombosis(DVT) in lower limbs of orthopedic inpatients, and provide reference for clinical nursing and prevention of thrombosis. Methods A retrospective case-control approach was used in this study. A total of 148 orthopedic inpatients diagnosed with DVT in the First Affiliated Hospital of Soochow University from February 2014 to October 2018 were selected as the case group. At the same time, 148 orthopaedic inpatients with undiagnosed DVT in the same Department were randomly selected as the control group. The electronic medical history data and related laboratory examination indexes of the two groups of patients during hospitalization in Orthopedics Department were analyzed retrospectively. Gender, age, seven indicators of blood coagulation, as well as history of hypertension, diabetes, history of DVT and other common risk factors of DVT in the two groups were statistically analyzed. Results In the case group, 63 patients (42.5%) DVT developed in the right lower extremity. The differences in the clinical symptoms and characteristics of fever, pulmonary infection, cough, expectoration, chest distress and shortness of breath, pleural effusion and constipation between the two groups were statistically significant (χ2 value was 5.688-12.312, P<0.01 or 0.05). Single factor analysis of related risk factors showed the differences of age, type of injury, lower limb joint replacement, a plaster cast, hypertension, history of DVT, central venous catheter, D-dimer and preoperative albumin levels, fibrinogen degradation products, and red blood cell count between the two groups were statistically significant (t value was-7.275-3.998, χ2 value was 4.889-13.305, Z value was-3.500--3.454, P < 0.01). Multivariate Logistic regression analysis showed that lower limb joint replacement(OR=0.383, 95%CI0.190-0.773), cough (OR=0.085, 95%CI0.010-0.731), chest distress and shortness of breath (OR=0.240, 95%CI0.077-0.745), constipation (OR=0.312, 95%CI0.135-0.718), red blood cell count (OR=3.314, 95%CI 2.105-5.216), hypertension (OR=0.534, 95%CI0.292-0.976) were independent risk factors for DVT formation in orthopedic inpatients (P<0.01 or 0.05). Conclusions DVT in orthopedic inpatients is a common result of multiple factors, among which, lower limb joint replacement, cough, chest distress and shortness of breath, constipation, red blood cell count and hypertension are independent risk factor, which should be monitored and given preventive care. Key words: Deep venous thrombosis; Orthopedic inpatient; Risk factor; Logistic regression

Meta-Analysis of Randomized Controlled Trials of Xueshuantong Injection in Prevention of Deep Venous Thrombosis of Lower Extremity after Orthopedic Surgery.

Objective To systematically evaluate the clinical efficacy of Xueshuantong injection (Panax notoginseng saponins) in preventing deep venous thrombosis (DVT) of lower extremity after orthopedic surgery. Methods The randomized controlled trials (RCTs) of Xueshuantong injection in prevention of lower extremity DVT after orthopedic surgery were retrieved from CNKI, Wanfang database, VIP, PubMed, and Cochrane Library by August 2020. Revman5.2 was used to analyze the results. Results A total of 20 articles including 2336 patients were included. The results of meta-analysis showed that the incidence of DVT in the experimental group was lower than that in the control group; after operation, the D-dimer (Ddimer), thrombin time (APTT), and prothrombin time (PT) in the experimental group were significantly improved compared with those in the control group, and the difference between the two groups was statistically significant. Conclusion Xueshuantong injection can effectively prevent the formation of lower extremity DVT after orthopedic surgery and antagonize the postoperative hypercoagulable state of blood, which has high clinical value.

IL (Interleukin)-6 Contributes to Deep Vein Thrombosis and Is Negatively Regulated by miR-338-5p.

Deep venous thrombosis (DVT), one of the most common venous thromboembolic disorders, is closely linked with pulmonary embolism and post-thrombotic syndrome, both of which have a high mortality. However, the factors that trigger DVT formation are still largely unknown. Elevated expression of IL (interleukin)-6-an important inflammatory cytokine-has been linked with DVT formation. However, the molecular mechanisms leading to the elevated IL-6 in DVT remain unclear. Here, we proposed that epigenetic modification of IL-6 at the post-transcriptional level may be a crucial trigger for IL-6 upregulation in DVT. Approach and Results: To explore the association between microRNAs and IL-6 in DVT, we performed microRNA microarray analysis and experiments both in vitro and in vivo. Microarray and quantitative real-time polymerase chain reaction results showed that IL-6 expression was increased while miR-338-5p level was decreased substantially in peripheral blood mononuclear cells of patients with DVT, and there was significant negative correlation between miR-338-5p and IL-6. Experiments in vitro showed that overexpressed miR-338-5p reduced IL-6 expression, while miR-338-5p knockdown increased IL-6 expression. Moreover, our in vivo study found that mice with anti-IL-6 antibody or agomiR-338-5p delivery resulted in decreased IL-6 expression and alleviated DVT formation, whereas antagomiR-338-5p acted inversely. Most of miR-338-5p was found located in cytoplasm by fluorescence in situ hybridization. Dual-luciferase reporter assay identified direct binding between miR-338-5p and IL-6. Our results suggest that decreased miR-338-5p promotes DVT formation by increasing IL-6 expression.

Study of risk factors for lower extremity deep venous thrombosis in elderly patients with degenerative diseases of the spine

Objective To explore the risk factors of lower extremity deep venous thrombosis (DVT) after orthopedic surgery in orthopedic patients. Methods We retrospectively analyzed 500 patients who underwent surgery in orthopedics due to degenerative diseases of the spine from September 2016 to May 2019. All patients underwent ultrasound examination of the lower extremities before surgery to confirm the absence of thrombosis Double lower extremity ultrasound on the 3th, 6th, 9th and 12th postoperative day. According to the results of ultrasound, the patients were divided into DVT group and non-DVT group. A total of 65 cases of DVT were diagnosed and the DVT formation rate was 13%. The age, D-dimer, body mass index (BMI), comorbidity, preoperative and postoperative coagulation, operation time, Logistic multivariate regression analysis of hospitalization time, intraoperative blood loss, etc. to explore risk factors associated with DVT. Results A total of 500 patients were included for analysis, According to the final results, 65 patients were included in the DVT group, and 435 were included in the non-DVT group. The incidence of DVT was 13%. Univariate analysis showed statistically significant differences in age, BMI, and hypertension between the two groups (P<0.05). Logistic regression analysis showed D-dimer [odds ratio (OR)=7.059, 95% confidence interval (CI)=2.864-17.401], OR=1.836, 95%CI=1.022-3.301) and operative time (OR=1.513, 95%CI= 1.039-2.203) is a risk factor for postoperative lower extremity DVT. Conclusion Obesity, D-dimer and long operation time are independent risk factors for lower extremity DVT. Key words: Spinal degenerative disease; Lower extremity deep venous thrombosis; Risk factor

Clinical characteristics and nursing of lower extremity deep vein thrombosis in elderly patients in Intensive Care Unit of Neurology Department

Objective To analyze the clinical characteristics of lower extremity deep venous thrombosis (DVT) in elderly patients in Intensive Care Unit (ICU) of Neurology Department, and to provide evidence for early implementation of preventive strategies. Methods Totally 229 patients who were admitted to the ICU of Neurology Department in a hospital from March 2017 to October 2018 were collected as the participants of the study and divided into the elderly group (age≥60 years) and non-elderly group (age<60 years) according to their ages. Self-designed questionnaire was used to collect the patients' general information, relevant factors of the lower extremity DVT, and information of commonly seen problems in elderly population such as history of hypertension and diabetes. SPSS 22.0 was used for data analysis. Results Among the 229 patients, 97 were diagnosed as lower extremity DVT, the incidence was 42.4%. Among them, the number of lower extremity DVT in the elderly group was 62, and the incidence was 57.4%, while the number in the non-elderly group was 35, and the incidence was 28.9%, and there was statistically significant difference between the two groups (P 0.05) , and the main type of DVT was intramuscular venous thrombosis. Conclusions Ischemic cerebrovascular disease, high level fibrinogen accompanied by hypertension, diabetes mellitus and heart disease are the main factors of DVT formation in the lower extremity of elderly patients in ICU of Neurology Department. Reducing hormone use is the protective factor of DVT prevention in lower extremities. Neurological ICU needs to pay early attention to the occurrence of DVT in the lower extremities of the elderly, especially the intramuscular venous thrombosis. Early prevention and interventions should be initiated to reduce the incidence of DVT in the lower extremities of elderly patients in Neurological ICU. Key words: Venous thrombosis; Lower extremity; Department of Neurology; Intensive Care Unit

Analysis of occurrence regularity and risk factors of deep venous thrombosis in patients with distal fractures of the knee during perioperative period

Objective To investigate the occurrence of deep venous thrombosis (DVT) in the perioperative period of patients with fracture distal to the knee, so that clinicians have a better understanding of the occurrence of DVT in the perioperative period of the fracture distal to the knee. Methods A retrospective analysis of the clinical data of 365 patients with distal knee fractures who underwent surgery in the Department of Orthopaedics Trauma, Xi′an Jiaotong University Medical College Red Cross Hospital from June 2014 to March 2018 was conducted. There were 213 males and 152 females, aged (45.05±15.24) years, with an age range of 17-83 years. Classification of fracture sites: 177 cases of tibiofibular shaft fracture, 130 cases of ankle fracture, and 58 cases of foot fracture. According to whether thrombosis occurred or not, the patients were divided into thrombotic group and non-thrombotic group before and after operation. There were 66 patients with thrombosis before operation, 299 patients without thrombosis before operation, 88 patients with thrombosis after operation, and 277 patients without thrombosis after operation. The incidence of thrombosis and the location of the thrombus were recorded. The sex, age, fracture site, ASA score, operation time, the time from injury to admission, the time from injury to surgery, intraoperative tourniquet time, intraoperative blood transfusion volume, intraoperative blood loss, intraoperative transfusion volume, hemoglobin volume at admission and 1 day after operation, D-dimer level at admission and 1 day after operation, multiple injuries, chronic hepatitis and medical diseases were analyzed. The measurement data of normal distribution and homogeneity of variance were expressed as mean±standard deviation (Mean±SD), the t test was used for comparison between two groups. The comparison of count data was performed by χ2 test or Fisher exact probability method, and multivariate logistic regression analysis was performed on the risk factors affecting the occurrence of DVT in both lower extremities. Results The preoperative DVT rate was 18.1% (66/365). In patients with thrombosis, distal thrombosis accounted for 93.94% (62/66), and mixed thrombosis accounted for 6.06% (4/66). The incidence of postoperative DVT was 24.1% (88/365). In patients with thrombosis, distal thrombosis accounted for 94.32% (83/88), proximal thrombosis accounted for 1.14% (1/88), and mixed thrombus accounted for 4.55% (4/88). Fracture site, ASA score, operation time, intraoperative tourniquet time, intraoperative blood transfusion volume, intraoperative blood loss, intraoperative transfusion volume were not statistically significant(P>0.05). Age ≥ 40 years (OR=2.691, 95% CI: 1.422-5.093, P=0.002), the time from injury to admission>3 days (OR=1.927, 95%CI: 1.072-3.463, P=0.028) were independent risk factors for DVT formation in fracture distal to the knee before operation. Age ≥ 40 years (OR=3.925, 95% CI: 2.161-7.129, P=0.000), the time from injury to surgery >5 days (OR=1.835, 95%CI: 1.080-3.119, P=0.025), D-dimer level at 1 day after operation (OR=1.191, 95%CI: 1.096-1.293, P=0.000), combined with multiple injuries (OR=1.981, 95%CI: 1.006-3.902, P=0.048), combined with coronary atherosclerotic heart disease (OR =2.692, 95%CI: 1.112-6.517, P=0.028) were independent risk factor for DVT formation after operation for fracture distal to the knee. Conclusions The occurrence of DVT before and after the fracture of the knee is mainly caused by distal thrombosis, and proximal thrombosis also occurs. Those patients aged≥40 years, combined with multiple injuries and coronary heart disease, should focus on preventing the occurrence of DVT. After the injury, the patient is immediately admitted to the hospital for DVT screening, and when the general condition allowed, shortening the preoperative waiting time can reduce the occurrence of DVT. Key words: Fracture; Venous thrombosis; Risk factors

Impression of Delayed Pelvic and Acetabular Fracture Fixation on the Prevalence of Preoperative Venous Thromboembolic Events

Background: Pelvic ring fractures (PRF) and acetabular fractures (AF) are among the most challenging orthopedic injuries. These injuries usually involve operative fixation, with considerable delay after the accident. There are limited studies regarding the effects of delayed surgery on the risk of venous thromboembolism (VTE) in these patients. Objectives: In this study, the effect of delayed fixation of PRF and AF on the risk of preoperative VTE was investigated. Methods: There were 86 patients with PRF and/or AF enrolled in the current study. Preoperatively, the presence of deep venous thrombosis (DVT) was examined utilizing Color Doppler ultrasound (CDU). The time interval between accident and CDU was recorded (time delay). Finally, the time delay was compared between patients with and without DVT formation. Results: The CDU revealed the presence of DVT in lower limb veins of 11 patients (12.8%). The time delay between the accident and CDU was significantly longer in patients with DVT formation (12.4 ± 4.1 days versus 7.6 ± 2.4 days; P < 0.001). Conclusions: Delayed fixation of PRF and AFmay increase the risk of preoperative VTE. The authors suggest surgical fixation in these patients as soon as possible in cases without definite contraindication for early fixation.

Repeat dose exposure of PM2.5 triggers the disseminated intravascular coagulation (DIC) in SD rats

Epidemiological evidence suggests that fine particulate matter (PM2.5) in air pollution promotes the formation of deep venous thrombosis. However, no evidence is available on the effects of PM2.5 lead to disseminated intravascular coagulation (DIC). For the first time, this study explored the effects of PM2.5 on DIC via coagulation disorders in vivo. SD rats received intratracheal instillation of PM2.5 once every three days for one month. Doppler ultrasound showed that the pulmonary valve (PV) and aortic valve (AV) peak flow were decreased after exposure to PM2.5. Fibrin deposition and bleeding were observed in lung tissue and vascular endothelial injury was found after exposure to PM2.5. Expression of thrombomodulin (TM) in vessel was downregulated after PM2.5-treated, whereas the levels of proinflammatory factors and adhesion molecules (IL-6, IL-1β, CRP, ICAM-1 and VCAM-1) were markedly elevated after exposure to PM2.5. Tissue factor (TF) and the coagulation factor of FXa were increased, while vWF was significantly lowered induced by PM2.5. Thrombin-antithrombin complex (TAT) and fibrinolytic factor (t-PA) were elevated, while there was no significantly change in the expression of anticoagulant factors (TFPI and AT-III). To clarify the relationship between PM2.5 and DIC, we examined the general diagnostic indices of DIC: PM2.5 prolonged PT and increased the expression of D-dimer but decreased platelet count and fibrinogen. In addition, the gene levels of JAK1 and STAT3 showed an upward trend, whereas there was little effect on JAK2 expression. And inflammatory factors (IL-6, IL-1β and TNF) in blood vessels of were up-reglated in PM2.5-treated rats. In summary, our results found that PM2.5 could induce inflammatory response, vascular endothelial injury and prothrombotic state, eventually resulted in DIC. It will provide new evidence for a link between PM2.5 and cardiovascular disease.

IL-17A promotes the formation of deep vein thrombosis in a mouse model

Deep venous thrombosis (DVT) is a significant problem in the health care industry worldwide. However, the factors and signaling pathways that trigger DVT formation are still largely unknown. In this study, we investigated the role of interleukin-17A (IL-17A) in DVT formation, focusing on the role of platelet aggregation, neutrophil infiltration, and endothelium cell (EC) activation. Notably, IL-17A levels increased in DVT patients as well as in a mouse DVT model. The DVT model mice were injected with recombinant mouse-IL-17A (rIL-17A) or anti-IL-17A monoclonal antibody (mAb) to further evaluate the effects of this cytokine. We found that rIL-17A promotes DVT formation, while IL-17A mAb represses DVT formation. Furthermore, platelet activation, highlighted by CD61 and CD49β expression, and aggregation were enhanced in platelets of rIL-17A-treated mice. rIL-17A also enhanced neutrophil infiltration by regulating the expression of macrophage inflammatory protein-2 (MIP-2) and the release of neutrophil extracellular traps (NETs). IL-17A mAb treatment inhibited both platelet activation and neutrophil activity. Moreover, rIL-17A appears to promote vein EC activation, while IL-17A mAb deters it. Taken together, these data suggest that IL-17A promotes DVT pathogenesis by enhancing platelet activation and aggregation, neutrophil infiltration, and EC activation and that anti-IL-17A mAb could be used for the treatment of DVT.

Deep vein thrombosis in mice is regulated by platelet HMGB1 through release of neutrophil-extracellular traps and DNA

Venous thromboembolic (VTE) disease, consisting of deep venous thrombosis (DVT) and pulmonary embolism (PE) is a leading cause of morbidity and mortality. Current prophylactic measures are insufficient to prevent all occurrence in part due to an incomplete understanding of the underlying pathophysiology. Mounting evidence describes interplay between activation of the innate immune system and thrombus development. Recent work has demonstrated that platelet release of HMGB1 leads to increased microvascular complications following injury. Additionally, platelet HMGB1 was found to enhance DVT and increase the formation of neutrophil extracellular traps (NETs), although the role of HMGB1 induced NET release in thrombosis remains unexplored. Utilizing a transgenic mouse lacking HMGB1 specifically from platelets and megakaryocytes we now demonstrate the specific role of platelet-derived HMGB1 in acute and subacute/chronic venous thrombosis. Platelets account for the majority of circulating HMGB1 and HMGB1 deposition within the developing clot. The pro-thrombotic effect of platelet-derived HMGB1 is mediated through enhanced neutrophil recruitment, NET formation and specifically release of extracellular DNA during NET formation. Taken together, these data suggest that platelet HMGB1 mediated NET release is a primary regulator of DVT formation in mice.

Think of May All the Day: A Case Report of May-Thurner Syndrome

[b]BACKGROUND[/b] May-Thurner syndrome occurs when the right common iliac artery compresses the left iliac vein against the fifth lumber vertebrae. The left iliac vein then becomes narrow and scarred. This leads to stasis of blood, predisposing to the formation of deep venous thrombosis (DVT) in the left iliofemoral vein, which can be recurrent and can cause pulmonary embolism (PE). [b]CASE REPORT[/b] In this case report, we describe the case of a 37-year-old woman who came for a second opinion about the cause of unprovoked PE and left iliofemoral DVT that she suffered from 2 months earlier. The diagnosis of MTS was made and the patient was referred to a vascular surgeon for further management. [b]CONCLUSIONS[/b] MTS should be in differential diagnosis of any case of unprovoked PE or left-sided lower limb DVT, especially in young females.

Novel microspheres reduce the formation of deep venous thrombosis and repair the vascular wall in a rat model.

L-Arginine (L-arg), widely known as a substrate for endogenous nitric oxide synthesis, can improve endothelial function associated with the vasculature, inhibit platelet aggregation, and alter the activity of vascular smooth muscle cells. P-selectin is a membrane component of the platelet alpha-granule and the endothelial cell-specific Wiebel–Palade body that plays a central role in mediating interactions between platelets and both leukocytes and the endothelium. The experiment was designed to evaluate the effect of novel microspheres with L-arg targeting P-selectin on the formation of deep vein thrombosis and repair of vascular wall in a rat model. Thrombosis of the inferior vena cava was induced by applying a piece of filter paper (5 mm × 10 mm) saturated with 10% FeCl3 solution for 5 min. Targeted microspheres with L-arg, targeted microspheres with water, and saline were injected into the tail veins of the rats after 30 min of applying the filter paper saturated with 10% FeCl3 solution. The dry weight and length of the thrombus isolated from the inferior vena cava were significantly decreased in the group with L-arg in microsphere after 24 h. No significant differences in prothrombin time, activated partial thromboplastin time, thrombin time, and fibrinogen among the groups were indicated. Images revealed that apoptosis in the vascular wall was less in the group injected with targeted microspheres with L-arg than in the other two groups at 1 and 8 d postsurgery. Meanwhile, cell proliferation was considerably excessive in the group injected with L-arg wrapped in targeted microspheres. Therefore, these novel microspheres could decrease the formation of thrombus in the early stages and in the subsequent periods of thrombosis. The microspheres can also enhance the vitality of impaired endothelial cells and reduce cell apoptosis.

Risk factors analysis of hypercoagulability and its effects on deep venous thrombosis formation in bedridden senile patients

Objective To investigate the clinical value of thromboelastogram(TEG) in predicting the deep venous thrombosis(DVT) formation of bedridden senile patients and further explore the risk factors for hypercoagulability in those patients. Methods Patients lying on bed for at least 1 year because of alzheimer's disease, stroke and fracture, aged between 70 to 90 years old, were selected in the Geriatrics Department of Shougang Hospital of Peking University from February 2013 to February 2014.Those patients were divided by Clotting composite index(CI) measured with TEG, CI less than and equal to 3 was control group, CI more than 3 was hypercoagulable group.The patients were followed-up for one year to identify the formation of DVT.Logistic regression analysis was used to analyze the independent risk factors of elderly patients with high blood coagulation state in bed. Results Two groups of baseline blood clots elastic graph indicators: Angle(α) of solidification, CI, coagulation time(K), the biggest thrombosis(MA), blood coagulation reaction time(R) comparative differences were statistically significant(P<0.05). In view of the bedridden elderly patients of high coagulation state, according to the result of single factor analysis of related factors, high coagulation state revealed with age(P=0.047), history of diabetes(P=0.001), bed time(P=0.043), tumor(P=0.001), fracture(P=0.002), but unrelated with sex, blood lipids, blood pressure, alcohol consumption, left ventricular ejection fraction.The multivariate logistic regression analysis indicated that fracture(OR(95%CI): 5.634(1.114~28.496), P=0.037), tumor(OR(95%CI): 4.652(1.142~18.955), P=0.032) and diabetes mellitus(OR(95%CI): 6.269(1.528~25.725), P=0.011) were independent risk factors for DVT. Conclusion The incidence of DVT in bedridden senile patients with hypercoagulability identified by CI is higher than those with normal coagulability.Tumor, fracture and diabetes mellitus are independent risk factors for DVT. Key words: Thromboelastogram; Clotting composite index; Deep venous thrombosis

Increased Lower Extremity Venous Stasis May Contribute to Deep Venous Thrombosis Formation after Microsurgical Breast Reconstruction-An Ultrasonographic Study.

Background Despite guideline-compliant prophylaxis, an increased rate of deep venous thrombosis (DVT) formation has been reported following autologous versus implant-based breast reconstruction. We hypothesized that tight abdominal fascia closure might decrease lower extremity venous return and promote venous stasis. Methods An observational crossover study of patients who underwent autologous breast reconstruction using transverse rectus abdominis musculocutaneous/deep inferior epigastric artery perforator flaps was conducted. Ultrasonographic measurements of the left common femoral vein (CFV) and right internal jugular vein (IJV) were performed preoperatively, in the postanesthesia care unit, and on postoperative day (POD) 1. Parameters of interest included vessel diameter, circumference, area, and maximum flow velocity. Results Eighteen patients with a mean age and body mass index of 52.7 years (range, 29-76 years) and 31.3 kg/m2 (range, 21.9-43.4 kg/m2) were included, respectively. A 29.8% increase in CFV diameter was observed on POD 1 (p < 0.0001). Similarly, a 24.3 and 69.9% increase in CFV circumference (p = 0.0007) and area (p < 0.0001) were noted, respectively. These correlated with a 28.4% decrease in maximum flow velocity in the CFV (p = 0.0001). Of note, none of these parameters displayed significant changes for the IJV, thus indicating that observed changes in the CFV were not the result of changes in perioperative fluid status. Conclusion Postoperative changes observed in the CFV reflect increased lower extremity venous stasis after microsurgical breast reconstruction and may contribute to postoperative DVT formation.

Active Ankle Movements Prevent Formation of Lower-Extremity Deep Venous Thrombosis After Orthopedic Surgery.

BackgroundThe aim of this study was to assess the preventive value of active ankle movements in the formation of lower-extremity deep venous thrombosis (DVT), attempting to develop a new method for rehabilitation nursing after orthopedic surgery.Material/MethodsWe randomly assigned 193 patients undergoing orthopedic surgery in the lower limbs into a case group (n=96) and a control group (n=97). The control group received routine nursing while the case group performed active ankle movements in addition to receiving routine nursing. Maximum venous outflow (MVO), maximum venous capacity (MVC), and blood rheology were measured and the incidence of DVT was recorded.ResultsOn the 11th and 14th days of the experiment, the case group had significantly higher MVO and MVC than the control group (all P<0.05). The whole-blood viscosity at high shear rate and the plasma viscosity were significantly lower in the case group than in the control group on the 14th day (both P<0.05). During the experiment, a significantly higher overall DVT incidence was recorded in the control group (8 with asymptomatic DVT) compared with the case group (1 with asymptomatic DVT) (P=0.034). During follow-up, the case group presented a significantly lower DVT incidence (1 with symptomatic DVT and 4 with asymptomatic DVT) than in the control group (5 with symptomatic DVT and 10 with asymptomatic DVT) (P=0.031).ConclusionsThrough increasing MVO and MVC and reducing blood rheology, active ankle movements may prevent the formation of lower-extremity DVT after orthopedic surgery.

MMP-3-1612 polymorphism - a risk factor for deep venous thrombosis formation.

We investigated the association of the 5A/6A polymorphism in the promoter region at -1612 of the matrix metalloproteinase-3 gene (MMP-3-1612) and deep venous thrombosis (DVT). The distribution of the MMP-3 (-1612 5A/6A) polymorphism in the case and control groups was detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Serum MMP-3 level of two groups was detected using enzyme-linked immunosorbent assay (ELISA). HepG2 cells containing MMP-3-1612 recombinant plasmid were cultured in vitro and the MMP-3 level was defined by luminescence intensity of luciferase. A DVT rat model was built. Serum MMP-3 level in the rats' wounded vein at different time points was detected by ELISA and recorded for investigation of the association between MMP-3 and DVT. Statistical data analysis was conducted with SPSS18.0. On the basis of the observation of MMP-3-1612 genotype frequency and allele frequency in the case and control groups, we identified significantly higher MMP-3-1612 5A allele frequency and higher serum MMP-3 level in the case group than in the control group (both P < 0.05). According to in vitro luciferase measurements, the 5A allele had higher transcriptional activity than the 6A allele. As observed in the rat model, serum MMP-3 level increased with time passing and thrombosis formation after modelling. The MMP-3-1612 5A/6A polymorphism may effect serum MMP-3 level and over-expression of serum MMP-3 level may be a risk factor for DVT formation.