Venous thrombosis and anticoagulant therapy

Epigallocatechin-3-gallate exerts protective effect on epithelial function via PI3K/AKT signaling in thrombosis

BACKGROUND

Venous thrombosis (VT) is one of the most frequent cardiovascular diseases, which seriously endangers people's health. Recently, the protective role of epigallocatechin-3-gallate (EGCG) against multiple cardiovascular diseases has been well studied. Nevertheless, whether EGCG is implicated in the progression of VT is still unclear.

METHODS

Rat models of VT were established by inferior vena cava (IVC) ligation. Histological characterization of the IVC tissues was examined by hematoxylin-eosin (H&E) staining. TUNEL assay was utilized to detect cell apoptosis in IVC tissues. The concentrations of the oxidative stress biomarkers, malondialdehyde (MDA) and superoxide dismutase (SOD), were estimated by corresponding kits. In addition, the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-8 in rat plasma were estimated by ELISA. Further, the expression levels of apoptosis markers (Bax, Bcl-2, and Cleaved-caspase 3) as well as key molecules p-PI3K and p-AKT in phosphoinositide 3-kinase (PI3K)/AKT signaling pathway were assessed by western blot.

RESULTS

Compared to the sham group, the model group showed obvious thrombus formation in IVC tissues, while the EGCG treatment significantly repressed thrombosis. EGCG inhibited cell apoptosis in IVC tissues of VT rat models. The decreased SOD concentration and increased MDA concentration in the plasma of VT rats were reversed by EGCG treatment. Additionally, the elevated levels of TNF-α, IL-6 and IL-8 in the plasma of VT rats can be partially reduced by the treatment of EGCG. Finally, we also found that EGCG reduced the levels of phosphorylated (p)-PI3K and p-AKT in IVC tissues of VT rat models, indicating that the hyperactivation of the PI3K/AKT signaling pathway was inhibited by EGCG.

CONCLUSION

This study proves that EGCG alleviates thrombosis, cell apoptosis, inflammatory response, and oxidative stress injury in VT by inactivating PI3K/AKT signaling pathway.

Effect of Enteral Immunonutrition in Patients Undergoing Surgery for Gastrointestinal Cancer: An Updated Systematic Review and Meta-Analysis

Background

The efficacy of enteral immunonutrition (EIN) in patients undergoing gastrointestinal cancer surgery remains debatable. This meta-analysis aimed to investigate the effectiveness of EIN administration in patients undergoing surgery for gastrointestinal cancer.

Methods

From January 2000 to January 2022, PubMed, EMBASE, Cochrane Library, and Web of Science were thoroughly searched for randomized controlled trials (RCTs) with EIN versus standard diet or no supplement in patients undergoing surgery for gastrointestinal cancer. Overall complications and infectious complications were the primary outcomes. The secondary results were non-infectious complications, mortality, length of hospital stay, and enteral nutrition-related complications.

Results

Thirty-five studies reporting 3,692 patients undergoing surgery for gastrointestinal cancer (including gastric cancer, colorectal cancer, esophageal cancer, periampullary cancer, or pancreatic cancer) were included. Compared with the control group, EIN group had a significantly decreased incidence of overall complications (RR = 0.79, p < 0.001). Infectious complications in patients who received EIN were considerably lower than in the control group (RR = 0.66, p < 0.001). Compared to the control group, the incidence of surgical site infection, abdominal abscess, anastomotic leakage, bacteremia, duration of systemic inflammatory response syndrome (SIRS), and duration of antibiotic therapy was significantly lower in the specific infectious complications treated with EIN. Still, there was no significant difference between the two groups with other infectious complications. Moreover, a substantial shortening in the length of hospital stay was shown in EIN group compared with the control group. Still, no significant effect of EIN was demonstrated in non-infectious complicatios and mortality. The enteral nutrition-related complications had no significant difference between two groups.

Conclusions

EIN is safe and effective in reducing overall complications, infectious complications, and hospital stay in patients undergoing gastrointestinal cancer surgery (including gastric cancer, colorectal cancer, esophageal cancer, periampullary cancer, or pancreatic cancer).

Characteristics of Deep Venous Thrombosis in Isolated Lower Extremity Fractures and Unsolved Problems in Guidelines: A Review of Recent Literature

Deep venous thrombosis (DVT) has been characterized by a disorder of venous return caused by abnormal blood clotting in deep veins. It often occurs in the lower limbs and is a common complication in orthopaedics. Therefore, relevant professional organizations domestic and overseas had formulated and constantly updated relevant guidelines to prevent the occurrence of DVT. According to the management strategy of the guidelines, the incidence of DVT can be significantly reduced. However, due to the variety of fractures types, the guidelines cannot expound precautions and characteristics of DVT for all fracture types at present, and there are other related unresolved problems. For example, there is still a lack of consistent optimal strategies for the management of DVT following isolated lower extremity fractures with a higher incidence. The best anticoagulant strategies for patients with upper limb fractures, pediatric fractures, and those combined with other injuries are rarely described in orthopaedic guidelines, but such fractures are common in clinical orthopaedics. The long‐term complications after DVT, such as post‐thrombotic syndrome, are not well‐understood. In the absence of clear guidance, orthopaedic surgeons often resort to empiric anticoagulation or conservative treatment, so the prevention effects of DVT are inconsistent. The purpose of this review is to summarize the characteristics of DVT events after isolated lower extremity fractures and to discuss the unsolved issues in the guidelines by reviewing the previous literature and tracing the history of DVT discovery, to provide more scientific and comprehensive recommendations for the prediction and prevention of DVT.

The Role of Pharmacomechanical Endovascular Intervention for Iliofemoral Vein Thrombosis Compared to Conventional Anticoagulation Therapy

Although anticoagulation therapy is the primary treatment for deep vein thrombosis (DVT), it has not been associated with the rapid recanalization of the venous occlusion. Moreover, it is associated with long-term disability due to post-thrombotic syndrome (PTS). In contrast, pharmacomechanical endovascular intervention (PMI) results in more rapid clinical improvement in DVT patients, but there are few reports on its long-term outcomes. This retrospective study evaluated the clinical effectiveness of PMI compared to conventional anticoagulation therapy (ACA) for acute and subacute iliofemoral DVT. We reviewed the medical records of 102 patients with iliofemoral DVT. A total of 46 patients for ACA and 56 patients for PMI were enrolled. We analyzed the clinical differences between the PMI and ACA groups by comparing the clinical signs, residual DVT free-rate, and PTS-free rate. There were no statistically significant differences in the demographic characteristics and risk factors except age between the groups (age: ACA, 52.0 ± 18.0 years; PMI, 59.0 ± 17.0 years; P = 0.035). The 1-, 3-, and 5-year residual DVT-free rate (ACA = 84.7%, 71.6%, and 46.0%; PMI = 82.1%, 76.8%, and 76.8%, respectively; P = 0.235) was not significantly different. However, the 1-, 3-, and 5-year PTS-free rate was significantly different (ACA = 93.5%, 74.0%, and 55.7%; PMI = 92.9%, 90.0%, and 90.0%, respectively; P = 0.019). There was no significant difference in the rate of other complications. PMI showed a lower incidence of PTS during the follow-up period. Therefore, PMI should be considered as an effective therapeutic modality for patients with iliofemoral DVT.

Global assays and the management of oral anticoagulation

Coagulation tests range from global or overall tests to assays specific to individual clotting factors and their inhibitors. Whether a particular test is influenced by an oral anticoagulant depends on the principle of the test and the type of oral anticoagulant. Knowledge on coagulation tests applicable in monitoring status and reversal of oral anticoagulation is a prerequisite when studying potential reversal agents or when managing anticoagulation in a clinical setting. Specialty tests based on the measurement of residual activated factor X (Xa) or thrombin activity, e.g., are highly effective for determining the concentration of the new generation direct factor Xa- and thrombin inhibitors, but these tests are unsuitable for the assessment of anticoagulation reversal by non-specific prohemostatic agents like prothrombin complex concentrate (PCC) and recombinant factor VIIa (FVIIa). Global coagulation assays, in this respect, seem more appropriate. This review evaluates the current status on the applicability of the global coagulation assays PT, APTT, thrombin generation and thromboelastography in the management of oral anticoagulation by vitamin K antagonists and the direct factor Xa and thrombin inhibitors. Although all global tests are influenced by both types of anticoagulants, not all tests are useful for monitoring anticoagulation and reversal thereof. Many (pre)analytical conditions are of influence on the assay readout, including the oral anticoagulant itself, the concentration of assay reagents and the presence of other elements like platelets and blood cells. Assay standardization, therefore, remains an issue of importance.

Pulmonary Embolic Disorders

Deaths due to pulmonary thromboemboli are frequently encountered by the forensic pathologist and account for a significant percentage of sudden, unexpected deaths. Diagnosing these straightforward cases is often not a challenge, but unfortunately some cases in which a thromboembolism is expected can become complicated. Occasionally, a postmortem clot may mimic a thromboembolism and lead to a mistaken diagnosis, and in other situations it may become paramount to attempt to age a thrombus as part of a medicolegal lawsuit. Additionally, many individuals use the less specific term, “pulmonary emboli”, when referring to these cases in which a portion of a thrombus, usually originating in the deep veins of the lower extremities, breaks off and travels to the pulmonary vasculature bed where it occludes vessels and leads to a rapid demise. One must remember, though, that several other materials and tissues including fat, amniotic fluid, air, tumors, solid organs, synthetic materials, and parasites may be displaced and embolize to the lungs and cause significant disease. In the following pages we will provide a thorough review of pulmonary embolic disorders, focusing on those diseases most likely to be encountered by the forensic pathologist. The aim of this review is to aid the pathologist in using proper terminology, diagnosing various types of embolic disorders, and recognizing potential mimics.

Magnetic resonance T1 relaxation time of venous thrombus is determined by iron processing and predicts susceptibility to lysis

BACKGROUND

The magnetic resonance longitudinal relaxation time (T1) changes with thrombus age in humans. In this study, we investigate the possible mechanisms that give rise to the T1 signal in venous thrombi and whether changes in T1 relaxation time are informative of the susceptibility to lysis.

METHODS AND RESULTS

Venous thrombosis was induced in the vena cava of BALB/C mice, and temporal changes in T1 relaxation time correlated with thrombus composition. The mean T1 relaxation time of thrombus was shortest at 7 days following thrombus induction and returned to that of blood as the thrombus resolved. T1 relaxation time was related to thrombus methemoglobin formation and further processing. Studies in inducible nitric oxide synthase (iNOS(-/-))-deficient mice revealed that inducible nitric oxide synthase mediates oxidation of erythrocyte lysis-derived iron to paramagnetic Fe3+, which causes thrombus T1 relaxation time shortening. Studies using chemokine receptor-2-deficient mice (Ccr2(-/-)) revealed that the return of the T1 signal to that of blood is regulated by removal of Fe3+ by macrophages that accumulate in the thrombus during its resolution. Quantification of T1 relaxation time was a good predictor of successful thrombolysis with a cutoff point of <747 ms having a sensitivity and specificity to predict successful lysis of 83% and 94%, respectively.

CONCLUSIONS

The source of the T1 signal in the thrombus results from the oxidation of iron (released from the lysis of trapped erythrocytes in the thrombus) to its paramagnetic Fe3+ form. Quantification of T1 relaxation time appears to be a good predictor of the success of thrombolysis.

Challenges in implementing government-directed VTE guidance for medical patients: a mixed methods study

BACKGROUND

Implementing venous thromboembolism (VTE) risk assessment guidance on admission to hospital has proved difficult worldwide. In 2010, VTE risk assessment in English hospitals was linked to financial sanctions. This study investigated possible barriers and facilitators for VTE risk assessment in medical patients and evaluated the impact of local and national initiatives.

SETTING

Acute Medical Unit in one English National Health Service university teaching hospital.

METHODS

This was a mixed methods study; National Research Ethics Service approval was granted. Data were collected over four 1-week periods; November 2009 (1), January 2010 (2), April 2010 (3) and April 2011 (4). Case notes for all medical patients admitted during these periods were reviewed. Thirty-six staff were observed admitting 71 of these patients; 24 observed staff participated in a structured interview.

RESULTS

876 case notes were reviewed. In total, 82.1% of patients had one or more VTE risk factors and 25.3% one or more bleeding risks. VTE risk assessment rose from a baseline of 6.9-19.6%, following local initiatives, and to 98.7% following financially sanctioned government targets. A similar increase in appropriate prescribing of prophylaxis was seen, but inappropriate prescribing also rose. No staff observed in period 1 conducted VTE risk assessment, risk-assessment forms were largely ignored or discarded during period 2; and electronic recording systems available during period 3 were not accessed. Few patients were asked any VTE-related questions in periods 1, 2 or 3. Interviewees' actual knowledge of VTE risk was not related to perceived knowledge level. Eight of the 24 staff interviewed were aware of national policies or guidance: none had seen them. Principal barriers identified to risk assessment were: involvement of multiple staff in individual admissions; interruptions; lack of policy awareness; time pressure and complexity of tools.

CONCLUSIONS

National financial sanctions appear effective in implementing guidance, where other local measures have failed.

Old and new anticoagulant drugs: a minireview

Abstract The limits of traditional anticoagulants, such as heparin and warfarin, have prompted the search for new agents for prophylaxis and treatment of arterial and venous thromboembolism, including factor Xa and thrombin inhibitors. These agents can be given orally, and their most significant advantage is that no laboratory monitoring is needed. The anti-Xa inhibitor rivaroxaban and the direct thrombin inhibitor dabigatran etexilate are licensed for prophylaxis of venous thromboembolism (VTE) in high-risk orthopedic surgery. They are at least as safe and effective as heparins but much more expensive. Dabigatran, rivaroxaban, and other agents currently in the pipeline of clinical development have the potential to replace warfarin in the two most frequent indications for anticoagulation, i.e. secondary prophylaxis of VTE and atrial fibrillation. Prevention and treatment of coronary artery thrombosis in patients with ischemic heart disease is another area of investigation for the role of new anticoagulants. These drugs have the potential to meet some currently unmet needs of traditional anticoagulants, but available clinical data warrant confirmation and expansion. Lack of specific antidotes for anticoagulation reversal and the high cost are important limitations of their use.

Venous thromboembolism and ethnicity

Venous thromboembolism (VTE) has long been considered a disease that affects predominantly white populations, a misconception resulting from a paucity of epidemiological data from non-Western countries, and the low incidence of hereditary thrombophilia in those of non-Caucasian background. Over the last decade, interest has grown in this area with the emergence of evidence that VTE is as prevalent, if not more so, in the black population and is also common in Asian groups. Much is still to be learned, as our current knowledge of hereditary thrombophilia and acquired risk factors do not fully explain the risk of VTE in non-Caucasian groups. This review summarises the current understanding of ethnic variation in VTE and highlights the need for further research in this area.

Effects of oral anticoagulation with various INR levels in deep vein thrombosis cases

AIM: In order to avoid the complications associated with thromboembolic disease, patients with this condition typically are placed on long-term anticoagulant therapy. This report compares bleeding complications in this patient population by level of achieved INR. MATERIALS AND METHODS: During the 6-year period between January 1997 and January 2003, 386 patients with venous thromboembolism of the lower extremities were admitted to the Cardiovascular Surgery Outpatient Clinic of Alsancak State Hospital. Of the 386 patients, 198 (51.2%) were women, and the average age was 52.3 years. All diagnoses of venous thromboembolism were confirmed by means of Doppler ultrasonography. Further investigation showed occult neoplasms in 22 (5.6%) of the cases. We excluded the patients with occult disease, and the remaining 364 constituted our study population. RESULTS: Oral anticoagulation was standardized at 6 months' duration in all cases. We divided the patients into two groups. Group I consisted of 192 patients (52.7%) with INR values between 1.9 and 2.5; Group II comprised 172 patients with INR values between 2.6 and 3.5. Complications in each group were assessed and compared. The minor hemorrhage rate was 1.04% in Group I and 4.06% in Group II. The major hemorrhage rate was also 1.04% in Group I and was 6.3% in Group II. We determined that the complication rates for both minor and major hemorrhage were significant in patients with INR values above 2.5. CONCLUSION: Oral anticoagulation must be followed closely in patients with venous thromboembolism. Higher INR levels are associated with significant increases in hemorrhage and associated complications. INR values of 2.0 to 2.5 are sufficient for long-term anticoagulant therapy, ensuring ideal anticoagulation levels and minimizing the complication rate.

Do anticoagulants improve survival in patients presenting with venous thromboembolism?

Anticoagulants have been available since around 1940 and have become the standard of treatment for venous thromboembolism (VTE) for over four decades. However, as with other treatments which became established before the evidence-based era, there is a paucity of evidence from randomized controlled trials validating their effectiveness in preventing the most feared complication of VTE, recurrent fatal pulmonary embolism (PE). Only two such trials have been performed, the results of which conflict. The bulk of data supporting their use are derived from three sources. First, studies of thromboprophylaxis, and comparisons of shorter and longer courses of anticoagulants in high-risk patients with established VTE have clearly demonstrated their effectiveness in primary and late secondary prevention. Given that heparin has an immediate onset of action, anticoagulants should therefore also be effective in early secondary prevention, the proposed mechanism of action in the acute treatment of VTE. Secondly, studies of inadequately treated patients have consistently shown higher recurrence rates than in those adequately treated. Finally, comparisons of outcomes in untreated and treated historical series, and of untreated historical series to treated series in the modern era have shown substantially lower rates of fatal PE in anticoagulated patients. Because these differences are so marked, harmonize with our current understanding of the mechanism of action of anticoagulants and are supported by other evidence, it is much more likely that they at least partly reflect the effectiveness of anticoagulants as opposed to being explicable purely in terms of accumulated biases and a changing distribution of disease severity.

Patients with acute pulmonary embolism should have an echocardiogram to guide treatment decisions

A 62-year-old man with a past medical history notable for hypertension, osteoarthritis, and calf deep vein thrombosis at age 55 following a total hip arthroplasty presents to the emergency department with acute-onset dyspnea and right-sided pleuritic chest pains. His medications consist of a calcium channel blocker and a COX-2 inhibitor. Pretest clinical suspicion for pulmonary embolism (PE) is high. Ventilation and perfusion lung scintigraphy are interpreted as being high-probability for PE. The nurse asks if a stat transthoracic echocardiogram should be ordered.