Basic mechanisms and pathogenesis of venous thrombosis

Locoregional recurrence of breast cancer presenting as upper limb venous thromboembolism

Locoregional recurrence of breast cancer is a major concern for both patient and oncologist. Presentation as venous thromboembolism (VTE) carries risk of delayed diagnosis and has a poor prognosis. Here we describe, for the first time in the literature, a delayed diagnosis of local recurrence of infiltrative inflammatory breast cancer presenting as extensive deep venous thrombosis of the upper arm veins. This case demonstrates the need for a high level of vigilance for recurrence of malignancy in patients with no concurrent risk factors for VTE and atypical clinical progression in order to reach a timely diagnosis.

Stasis Promotes Erythrocyte Adhesion to von Willebrand Factor

OBJECTIVE

Venous thromboembolism is a major contributor to global disease burden. Leukocytes and platelets initiate thrombogenesis on blood stasis and initiate the formation of a fibrin, VWF (von Willebrand factor), and neutrophil extracellular trap scaffold for erythrocytes. However, there is little knowledge on how erythrocytes become stably incorporated into this scaffold. Recently, we described the adhesion of calcium-loaded erythrocytes to endothelial-derived VWF strings. Because VWF is part of the scaffold of venous thrombi, we questioned whether reduced flow or stasis promotes the adhesion of normal erythrocytes to VWF and whether venous thrombi show evidence of erythrocyte-VWF interactions.

APPROACH AND RESULTS

In the present work, we perfused, under controlled shear conditions, washed, normal erythrocytes over surface-immobilized plasma and extracellular matrix proteins and showed that normal erythrocytes specifically bind to VWF. The interaction between erythrocytes and VWF significantly increased when the wall shear stress was reduced. Next, we investigated whether erythrocyte-VWF interactions support the structure of venous thrombi. High-resolution immunofluorescence imaging of human venous thrombi showed a striking pattern between erythrocytes, VWF, and fibrin, which suggests that VWF plays a supporting role, linking erythrocytes to fibrin in the thrombus.

CONCLUSIONS

Our data suggest that erythrocyte retention in venous thrombi is mediated by erythrocyte-VWF or erythrocyte-VWF-fibrin interactions. Targeting erythrocyte retention could be a new strategy in the treatment or prevention of venous thrombosis.

Modelling and simulation of flow and agglomeration in deep veins valves using discrete multi physics

The hemodynamics in flexible deep veins valves is modelled by means of discrete multi-physics and an agglomeration algorithm is implemented to account for blood accrual in the flow. Computer simulations of a number of valves typologies are carried out. The results show that the rigidity and the length of the valve leaflets play a crucial role on both mechanical stress and stagnation in the flow. Rigid and short membranes may be inefficient in preventing blood reflux, but reduce the volume of stagnant blood potentially lowering the chances of thrombosis. Additionally, we also show that in venous valves, cell agglomeration is driven by stagnation rather than mechanical stress.

In Vivo Role of Neutrophil Extracellular Traps in Antiphospholipid Antibody-Mediated Venous Thrombosis

OBJECTIVE

Antiphospholipid syndrome (APS) is a leading acquired cause of thrombotic events. Although antiphospholipid antibodies have been shown to promote thrombosis in mice, the role of neutrophils has not been explicitly studied. The aim of this study was to characterize neutrophils in the context of a new model of antiphospholipid antibody-mediated venous thrombosis.

METHODS

Mice were administered fractions of IgG obtained from patients with APS. At the same time, blood flow through the inferior vena cava was reduced by induction of stenosis. Resulting thrombi were characterized for size and neutrophil content. Circulating factors and the vessel wall were also assessed.

RESULTS

As measured by both thrombus weight and thrombosis frequency, mice treated with IgG from patients with APS (APS IgG) demonstrated exaggerated thrombosis as compared with control IgG-treated mice. Thrombi in mice treated with APS IgG were enriched for citrullinated histone H3 (a marker of neutrophil extracellular traps [NETs]). APS IgG-treated mice also demonstrated elevated levels of circulating cell-free DNA and human IgG bound to the neutrophil surface. In contrast, circulating neutrophil numbers and markers of vessel wall activation were not appreciably different between APS IgG-treated mice and control mice. Treatment with either DNase (which dissolves NETs) or a neutrophil-depleting antibody reduced thrombosis in APS IgG-treated mice to the level in control mice.

CONCLUSION

These data support a mechanism whereby circulating neutrophils are primed by antiphospholipid antibodies to accelerate thrombosis. This line of investigation suggests new, immunomodulatory approaches for the treatment of APS.

Novel insights into the regulation of coagulation by factor V isoforms, tissue factor pathway inhibitorα, and protein S

Factor V (FV) is a regulator of both pro- and anticoagulant pathways. It circulates as a single-chain procofactor, which is activated by thrombin or FXa to FVa that serves as cofactor for FXa in prothrombin activation. The cofactor function of FVa is regulated by activated protein C (APC) and protein S. FV can also function as an anticoagulant APC cofactor in the inhibition of FVIIIa in the membrane-bound tenase complex (FIXa/FVIIIa). In recent years, it has become clear that FV also functions in multiple ways in the tissue factor pathway inhibitor (TFPI) anticoagulant pathway. Of particular importance is a FV splice variant (FV-Short) that serves as a carrier and cofactor to TFPIα in the inhibition of FXa. FV-Short is generated through alternative splicing of exon 13 that encodes the large activation B domain. A highly negatively charged binding site for TFPIα is exposed in the C-terminus of the FV-Short B domain, which binds the positively charged C-terminus of TFPIα, thus keeping TFPIα in circulation. The binding of TFPIα to FV-Short is also instrumental in localizing the inhibitor to the surface of negatively charged phospholipids, where TFPIα inhibits FXa in process that is stimulated by protein S. Plasma FV activation intermediates and partially proteolyzed platelet FV similarly bind TFPIα with high affinity and regulate formation of prothrombinase. The novel insights gained into the interaction between FV isoforms, TFPIα, and protein S have opened a new avenue for research about the mechanisms of coagulation regulation and also for future development of therapeutics aimed at modulating coagulation.

New developments and future challenges of nuclear medicine and molecular imaging for pulmonary embolism

Although widely validated, current tests for pulmonary embolism (PE) diagnosis, i.e. computed tomography pulmonary angiography (CTPA) and V/Q planar scintigraphy, have some limitations. Drawbacks of CTPA include the radiation dose, some contra indications and a rising concern about a possible overdiagnosis/overtreatment of PE. On the other hand, V/Q planar scintigraphy has a high rate of non-diagnostic tests responsible for complex diagnostic algorithms. Since the PIOPED study, imaging equipment and radiopharmaceuticals have greatly evolved allowing the introduction of techniques that improve imaging of lung ventilation and perfusion. Single photon emission computed tomography (SPECT) and SPECT/CT techniques are already largely used in daily practice and have been described to have greater diagnostic performance and much fewer non-diagnostic tests as compared with planar scintigraphy. However, they have not yet been firmly validated in large scale prospective outcome studies. More recently, it has also been proposed to image pulmonary perfusion and ventilation using positron emission tomography (PET), which has an inherent technical superiority as compared to conventional scintigraphy and may provide new insight for pulmonary embolism. Regardless of modality, these new thoracic imaging modalities have to be integrated into diagnostic strategies. The other major challenge for venous thromboembolism diagnosis may be the potential additional value of molecular imaging allowing specific targeting of thrombi in order, for example, to differentiate venous thromboembolism from tumor or septic thrombus, or acute from residual disease. In this article, the new imaging procedures of lung ventilation perfusion imaging with SPECT, SPECT/CT and PET/CT are discussed. We also review the current status and future challenge of molecular imaging for the in vivo characterization of venous thromboembolism.

Increased risks of venous thromboembolism in patients with psoriasis. A Nationwide Cohort Study

Systemic inflammation and hypercoagulability in psoriasis are related to cardiovascular morbidity. The aim of the study was to investigate the incidence and risk of venous thromboembolism (VTE) in patients with psoriasis in Taiwan. We identified inpatients aged ≥ 18 years with a diagnosis of psoriasis and controls at a 1: 1 ratio of frequency matched by sex, age, frequency of medical visits, length of stay, and comorbidities between 2000 and 2010 in the Taiwan National Health Insurance Research Database. Each patient was traced to the date of VTE occurrence, loss to follow-up, death, or the December 31, 2011, whichever occurred first. We analysed 8945 patients with psoriasis and 8945 controls. The patients with psoriasis exhibited a greater incidence rate of VTE (19.2 vs 9.88 per 10 000 person-years) than did the controls. After adjustment for covariates, the patients with psoriasis presented a 2.02-fold risk of VTE (adjusted hazard ratio [aHR] = 2.02, 95 % confidence interval [CI] = 1.42-2.88) compared with that in the control cohort. The aHR of VTE was significantly higher in the first year of follow-up (aHR = 3.30, 95 % CI = 1.45-7.55) than after one year (aHR = 1.68, 95 % CI = 1.13-2.49).

Oral Thrombus: Report of 122 cases with clinically descriptive data

BACKGROUND

The aim of the present study was to assess the frequency and characterize clinic-pathologic aspects of thrombus occurring as a single lesion or in association with other oral pathologies.

MATERIAL AND METHODS

122 cases of thrombus from the oral cavity were retrieved. Information regarding site of the lesion, age, sex and clinical diagnosis or hypothesis and associated lesions were collected from the patients' records.

RESULTS

The lesions occurred in a wide age range but the 5th decade was the most prevalent and female patients were more affected. The most frequent site for the lesion was the lip, followed by tongue, buccal mucosa, alveolar ridge, gingiva, floor of the mouth and vestibule. Thirty-five cases were associated with other vascular anomalies or actinic cheilitis. Microscopically, typical thrombus morphology was present. Organized thrombus presented neovascularization and fibroblasts, associated with hemorrhagic areas.

CONCLUSIONS

Only 4 cases of oral thrombus have been described in the oral cavity. Given the limited number of cases reported, the importance of a thrombus in the oral cavity is not well established. This study contributes to establishing the profile of patients presenting oral thrombus, a lesion not rare but not well documented.

Replicative senescence promotes prothrombotic responses in endothelial cells: Role of NADPH oxidase- and cyclooxygenase-derived oxidative stress

Endothelial senescence has been suggested to promote endothelial dysfunction in age-related vascular disorders. This study evaluated the prothrombotic properties of senescent endothelial cells (ECs) and the underlying mechanism. Serial passaging from passage (P)1 to P4 (replicative senescence) of porcine coronary artery ECs, or treatment of P1 ECs with the endothelial nitric oxide synthase (eNOS) inhibitor L-NAME (premature senescence) induced acquisition of markers of senescence including increased senescence-associated-β-galactosidase (SA-β-gal) activity and p53, p21, p16 expression. Approximately 55% of P3 cells were senescent with a high level oxidative stress, and decreased eNOS-derived nitric oxide (NO) formation associated with increased expression of NADPH oxidase subunits (gp91phox, p47phox), cyclooxygenase (COX)-2 but not COX-1, and a decreased eNOS expression leading to a reduced ability of ECs to inhibit platelet aggregation. P3 cells also presented increased expression and activity of tissue factor (TF), a key initiator of the coagulation cascade. Treatment of senesecent cells with a NADPH oxidase inhibitor (VAS-2870) or by a COX inhibitor (indomethacin) reduced oxidative stress, decreased TF activity and expression, and reduced the expression of gp91phox, p47phox and COX-2 and restored the ability of ECs to inhibit effectively platelet aggregation. Thus, replicative endothelial senescence promotes a prothrombotic response involving the down-regulation of the protective NO pathway and the upregulation of the NADPH oxidase- and COXs-dependent oxidative stress pathway promoting TF expression and activity.

Mice with a deficiency in CLEC-2 are protected against deep vein thrombosis

Deep vein thrombosis (DVT) with its major complication, pulmonary embolism, is a global health problem. Mechanisms of DVT remain incompletely understood. Platelets play a role in DVT, but the impact of specific platelet receptors remains unclear. Platelet C-type lectin-like receptor 2 (CLEC-2) is known to maintain the physiological state of blood vasculature under inflammatory conditions. DVT is a thromboinflammatory disorder developing largely as sterile inflammation in the vessel wall. We hypothesized therefore that CLEC-2 might play a role in DVT. Here, using a murine DVT model of inferior vena cava (IVC) stenosis, we demonstrate that mice with general inducible deletion of CLEC-2 or platelet-specific deficiency in CLEC-2 are protected against DVT. No phenotype in the complete stasis model was observed. Transfusion of wild-type platelets into platelet-specific CLEC-2 knockout mice restored thrombosis. Deficiency in CLEC-2 as well as inhibition of podoplanin, a ligand of CLEC-2, was associated with reduced platelet accumulation at the IVC wall after 6 hours of stenosis. Podoplanin was expressed in the IVC wall, where it was localized in the vicinity of the abluminal side of the endothelium. The level of podoplanin in the IVC increased after 48 hours of stenosis to a substantially higher extent in mice with a thrombus vs those without a thrombus. Treatment of animals with an anti-podoplanin neutralizing antibody resulted in development of smaller thrombi. Thus, we propose a novel mechanism of DVT, whereby CLEC-2 and upregulation of podoplanin expression in the venous wall trigger thrombus formation.

Pathogenesis of Thromboembolism and Endovascular Management

Venous thromboembolism (VTE), a disease that includes deep venous thrombosis (DVT) and pulmonary embolism (PE), is associated with high mortality, morbidity, and costs. It can result in long-term complications that include postthrombotic syndrome (PTS) adding to its morbidity. VTE affects 1/1000 patients, costs $13.5 billion annually to treat, and claims 100,000 lives annually in the US. The current standard of care for VTE is anticoagulation, though thrombolysis may be performed in patients with PE and threatened limb. This review discusses pathogenesis and medical treatment of VTE and then focuses on endovascular treatment modalities. Mechanical- and catheter-directed thrombolysis (CDT) is discussed, as well as patient selection criteria, and complications. The first prospective study (CaVenT) comparing CDT with anticoagulation alone in acute DVT, despite study shortcomings, corroborates the existing literature indicating improved outcomes with CDT. The potential of the ongoing prospective, multicenter, randomized ATTRACT trial is also highlighted.

Hypercoagulation and complement: Connected players in tumor development and metastases

Hypercoagulation is a common feature of several tumors to the extent that individuals with coagulation defects often present with occult visceral cancers. Recent evidence has shown that hypercoagulation is not just a mere secondary effect due to the presence of the tumor, rather it actively contributes to tumor development and dissemination. Among the numerous mechanisms that can contribute to cancer-associated hypercoagulation, the ones involving immune-mediated processes are gaining increasing attention. In particular, complement cascade and hypercoagulation are one inducing the other in a vicious circle that involves neutrophil extracellular traps (NETs) formation. Together, in this feedback loop, they can promote the protumorigenic phenotype of immune cells and the protection of tumor cells from immune attack, ultimately favouring tumor development, progression and metastases formation. In this review, we summarize the role of these processes in cancer development and highlight new possible intervention strategies based on anticoagulants that can arrest this vicious circle.

Predicting and preventing thromboembolic events in patients receiving cisplatin-based chemotherapy for germ cell tumours

BACKGROUND

Patients with germ cell tumours (GCT) receiving cisplatin-based chemotherapy are at high risk of thromboembolic events (TEE). Previously, we identified serum lactate dehydrogenase (LDH) and body surface area (BSA) as independent predictive factors for TEE. The aim of this study was to validate these predictive factors and to assess the impact of thromboembolism prophylaxis in patients at risk of deep venous thrombosis (DVT).

METHODS

Between 2001 and 2014, 295 patients received first-line cisplatin-based chemotherapy for GCT. Preventive anticoagulation with low-molecular-weight heparin (LMWH) was progressively implemented in patients with predictive factors. Sixteen patients with evidence of TEE before starting chemotherapy were excluded from the analysis.

RESULTS

Among 279 eligible patients, a TEE occurred in 38 (14%) consisting of DVT (n = 26), arterial thrombosis (n = 2), and superficial thrombophlebitis (n = 10). DVT occurred in 26 (12.7%) of 204 patients with risk factors versus two (2.6%) of 75 patients with no risk factors (p = 0.01). After a prevention protocol was progressively implemented from 2005, primary thromboprophylaxis was administered to 104 patients (68%) with risk factors. Among patients at risk (n = 151), the incidence of DVT decreased by roughly half when they received a LMWH: 9/97 (9.2%) and 9/54 (16.6%), respectively (p = 0.23).

CONCLUSION

Patients with GCT who receive cisplatin-based chemotherapy are at risk of developing a TEE which can be predicted by elevated serum LDH. To our knowledge this is the first study exploring LMWH as thromboprophylaxis in GCT patients. A prospective trial testing prophylactic anticoagulation is warranted.

Early Postoperative Complications After Shoulder Arthroplasty in Patients With Epilepsy

Epilepsy is the most common serious neurological disorder in the United States, but little is known about its effect in the perioperative shoulder surgery setting. The authors sought to determine whether patients with epilepsy undergoing shoulder arthroplasty would be at increased risk for in-hospital adverse events, prolonged length of stay, and nonroutine disposition. Using the National Inpatient Sample (2002-2011), 422,371 adults undergoing shoulder arthroplasty were identified, 3714 (0.9%) of whom had epilepsy. Comparisons of perioperative outcomes were performed by multivariable logistic regression modeling. The authors found that patients with epilepsy were more likely to experience postoperative adverse events (odds ratio [OR], 1.68; 95% confidence interval [CI], 1.54-1.84), including mechanical ventilation (OR, 3.91; 95% CI, 2.81-5.44), gastrointestinal complication (OR, 3.86; 95% CI, 2.78-5.37), deep venous thrombosis (OR, 3.23; 95% CI, 2.22-4.69), pneumonia (OR, 1.66; 95% CI, 1.35-2.04), posthemorrhagic anemia (OR, 1.57; 95% CI, 1.42-1.73), transfusion (OR, 1.56; 95% CI, 1.41-1.72), and acute renal failure (OR, 1.34; 95% CI, 1.04-1.74). An epilepsy diagnosis was also associated with increased odds for prolonged hospital stay (OR, 1.39; 95% CI, 1.28-1.52) and nonroutine discharge (OR, 1.80; 95% CI, 1.67-1.94). This study concludes that patients with epilepsy are at higher risk for early postoperative complications and resource use following shoulder arthroplasty surgery. Awareness of these risks may allow more targeted perioperative management of these patients to optimize postoperative outcomes and limit complications. [Orthopedics. 2016; 39(6):e1075-e1079.].

Is forgoing chemical venous thromboembolism prophylaxis for women undergoing breast-conserving surgery for breast cancer safe?

BACKGROUND

Cancer patients have a 4 to 7 fold increased risk of venous thromboembolism (VTE) vs the normal population. Chest guidelines recommend no chemical VTE prophylaxis for women with a <1.5% risk for VTE. Although the risk of VTE among women undergoing breast-conserving therapy is reported to be low overall, the rate without chemical prophylaxis has not been defined. The objective of the study was to establish the VTE risk among women undergoing breast-conserving surgery (BCS) who did not receive chemical VTE prophylaxis.

METHODS

From a prospective breast cancer database, 1,000 consecutive patients who underwent BCS without chemical VTE prophylaxis and with mechanical prophylaxis (support hose and intermittent pneumatic compression devices) were analyzed for VTE occurrence within 30 days postoperatively. Institutional review board approval was obtained.

RESULTS

The mean age was 65.4 ± 11.7 years, and mean body mass index was 27.3 ± 5.7. About 81.9% of the patients were postmenopausal. Median tumor size was 1.1 cm, and 24.7% of patients had lymph node metastases. The 30-day rate of clinically significant VTE was 0% (95% CI 0% to .37%). Hematomas requiring surgical intervention occurred among .6% of patients.

CONCLUSIONS

This cohort demonstrates that breast cancer patients undergoing BCS may be safely managed without chemical VTE prophylaxis because the risk with only mechanical prophylaxis is acceptable.

Von Willebrand factor is reversibly decreased during torpor in 13-lined ground squirrels

During torpor in a hibernating mammal, decreased blood flow increases the risk of blood clots such as deep vein thrombi (DVT). In other animal models platelets, neutrophils, monocytes and von Willebrand factor (VWF) have been found in DVT. Previous research has shown that hibernating mammals decrease their levels of platelets and clotting factors VIII (FVIII) and IX (FIX), increasing both bleeding time and activated partial thromboplastin time. In this study, FVIII, FIX and VWF activities and mRNA levels were measured in torpid and non-hibernating ground squirrels (Ictidomys tridecemlineatus). Here, we show that VWF high molecular weight multimers, collagen-binding activity, lung mRNA and promoter activity decrease during torpor. The VWF multimers reappear in plasma within 2 h of arousal in the spring. Similarly, FIX activity and liver mRNA both dropped threefold during torpor. In contrast, FVIII liver mRNA levels increased twofold while its activity dropped threefold, consistent with a post-transcriptional decrease in FVIII stability in the plasma due to decreased VWF levels. Finally, both neutrophils and monocytes are decreased eightfold during torpor which could slow the formation of DVT. In addition to providing insight in how blood clotting can be regulated to allow mammals to survive in extreme environments, hibernating ground squirrels provide an interesting model for studying.

The evolution of recombinant thrombolytics: Current status and future directions

Cardiovascular disorders are on the rise worldwide due to alcohol abuse, obesity, hypertension, raised blood lipids, diabetes and age-related risks. The use of classical antiplatelet and anticoagulant therapies combined with surgical intervention helped to clear blood clots during the inceptive years. However, the discovery of streptokinase and urokinase ushered the way of using these enzymes as thrombolytic agents to degrade the fibrin network with an issue of systemic hemorrhage. The development of second generation plasminogen activators like anistreplase and tissue plasminogen activator partially controlled this problem. The third generation molecules, majorly t-PA variants, showed desirable properties of improved stability, safety and efficacy with enhanced fibrin specificity. Plasmin variants are produced as direct fibrinolytic agents as a futuristic approach with targeted delivery of these drugs using liposome technlogy. The novel molecules from microbial, plant and animal origin present the future of direct thrombolytics due to their safety and ease of administration.

Popular naturally occurring antioxidants as potential anticoagulant drugs

Blood coagulation is a physiological process whose main task is prevention of blood loss from injured vessels. This process consists of a series of zymogens proteolytic activation leading to the generation of the main coagulation enzyme - thrombin. Besides its important role in blood coagulation process, thrombin is involved in many cardiovascular diseases, which are responsible for almost half of fatalities in economically developed countries. The evidence for the increased generation and in vivo activity of thrombin was observed in the plasma of individuals at high risk for clinically significant venous and arterial thromboembolic complications. Antioxidants activity of plants extracts has been well known for many years and was confirmed by many publications. However, during the last decade many research centers presented results suggesting anticoagulant potential of various plant extracts. Many researchers have also provided evidence that polyphenol compounds are able to inhibit the activity of many enzymes, including serine proteases. All research described in this review clearly indicate that polyphenols and polyphenol-rich extracts possess not only antioxidative but also anticoagulant properties and may be useful in creation of new therapeutic agents or dietary supplements. Based on described properties polyphenols would be very helpful with both prevention and treatment of thromboembolic complications associated with multiple failures of haemostasis, because the available therapeutic agents do not offer such double-effects (antioxidant and anticoagulant).

Measurement of extracellular vesicles as biomarkers of consequences or cause complications of pathological states, and prognosis of both evolution and therapeutic safety/efficacy

Utility of EVs, as biomarkers of cause or consequence of various pathological complications, and prognosis of blood components' therapy in terms of safety/efficacy and their potential associated hazards, primed by EVs involvements in pro-inflammatory, immunomodulatory and activations of both pro/anti-coagulatory and others associated pathways, as well as various cellular cross talks, are highlighted as the fundamental. Today EVs are becoming the "buzz" words of the current diagnosis, development and research [DDR] strategies, with the aim of ensuring safer therapeutic approaches in the current clinical practices, also incorporating their potential in long term cost effectiveness in health care systems. The main focus of this manuscript is to review the current opinions in some fundamental areas of EVs involvements in health and diseases. Firstly, our goal is highlighting what are EVs/MVs/MPs and how are they generated in physiology, pathology or blood products; classification and significance of EVs generated in vivo; followed by consequences and physiological/pathological induced effects of EVs generation in vivo. Secondly, specific cell origin EVs and association with malignancy; focus on EVs carrying TF and annexin V as a protective protein for harmful effects of EVs, and associations with LA; and incidence of anti-annexin V antibodies are also discussed. Thirdly, utility of EVs is presented: as diagnostic tools of disease markers; prognosis and follow-up of clinical states; evaluation of therapy efficacy; quality and risk assessment of blood products; followed by the laboratory tools for exploring, characterizing and measuring EVs, and/or their associated activity, using our own experiences of capture based assays. Finally, in perspective, the upcoming low volume sampling, fast, reliable and reproducibility and friendly use laboratory tools and the standardization of measurement methods are highlighted with the beneficial effects that we are witnessing in both wound healing and tissue remodeling, with an expected blockbuster status EVs as future therapeutic directions.

MMP3 -1171 5A/6A Promoter Genotype Influences Serum MMP3 Levels and Is Associated with Deep Venous Thrombosis

BACKGROUND

The aim of this study was to investigate the roles of MMP3 (matrix metalloproteinase-3) gene polymorphism and protein expression in deep venous thrombosis (DVT) among Chinese Han population.

METHODS

A total of 280 subjects were included in this study and categorized as case group (144 DVT patients) and control group (136 healthy individuals). Polymerase chain reaction-restriction fragment length polymorphism was used to detect MMP3 promoter -1171 5A>6A genotype and allele frequencies. MMP3 serum levels were measured by enzyme-linked immunosorbent assay. SPSS version 18.0 statistical software was used for data analysis.

RESULTS

There was significant difference in genotype frequencies of MMP3 gene -1171 5A>6A between the case group and the control group (all P < 0.05). Furthermore, the 6A allele on MMP3 -1171 5A>6A may be associated with increased risk of DVT (odds ratio 1.961, 95% confidence interval 1.309-2.939, P < 0.01). The MMP3 serum level in DVT patients was markedly higher than the control group (case group: 28.45 ± 10.97 vs.

CONTROL GROUP

18.18 ± 9.03, P < 0.05). Serum MMP3 level in DVT patients carrying 5A/6A and 6A/6A genotypes was higher than the control group (P < 0.05). The bilateral calf circumference difference was significantly higher in DVT patients than the control group among all the genotypes at MMP3 gene -1171 5A>6A (all P < 0.05).

CONCLUSION

MMP3 gene -1171 5A>6A polymorphism and upregulated protein expression may be associated with DVT risk in Chinese Han population.

Pro- and anticoagulant properties of factor V in pathogenesis of thrombosis and bleeding disorders

Factor V (FV) serves an important role in the regulation of blood coagulation, having both pro- and anticoagulant properties. The circulating high molecular weight single-chain FV molecule undergoes a series of proteolytic cleavages during both activation of coagulation and during anticoagulant regulation of coagulation by activated protein C (APC). It is noteworthy that mutations in the factor V gene (F5) either cause thrombosis or bleeding. New insights into the importance and complexity of FV functions have been generated from elucidation of the pathogenic mechanisms of two familial mutations in the F5 gene. The first mutation was identified as a result of the discovery of APC resistance as the most common risk factor for venous thrombosis. The mutation (FV Leiden) predicts the Arg(506) Gln replacement, which impairs the normal regulation of FVa by APC, as the Arg506 site is an important APC cleavage site. In addition, elucidation of APC resistance resulted in the discovery of the anticoagulant APC cofactor activity of FV. The second FV mutation (FV(A2440G) ), identified in a family with an autosomal dominant bleeding disorder, has led to the discovery of an alternative splicing generating a previously unidentified FV isoform (FV-Short), which inhibits coagulation via an unexpected and intriguing mechanism involving the coagulation inhibitor TFPI-α. These are naturally occurring mutations in the F5 gene that have generated new knowledge on the role of FV in regulation of coagulation and the importance of genetic risk factors for thrombosis and bleeding.

Orthostatic Hypotension and Risk of Venous Thromboembolism in 2 Cohort Studies

BACKGROUND

Although venous stasis is a risk factor for venous thromboembolism (VTE) and orthostatic hypotension (OH) can cause venous stasis, to our knowledge no study has examined the relationship between OH and VTE risk. We sought to quantify the association between OH and VTE (deep vein thrombosis or pulmonary embolism) using data from 2 large, prospective cohort studies: the Cardiovascular Health Study (CHS) and the Atherosclerosis Risk in Communities (ARIC) Study. We hypothesized that OH was positively associated with incident VTE.

METHODS

We measured OH-defined as a drop in systolic blood pressure (SBP) of at least 20 mm Hg or diastolic blood pressure (DBP) of at least 10 mm Hg within 3 minutes of standing-in participants aged 45-64 years in ARIC (n = 12,480) and ≥65 years in CHS (n = 5,027) at baseline visits (1987-1989 in ARIC; 1989-1990 and 1992-1993 in CHS), and followed participants for incident VTE (n = 568 in ARIC through 2011 and n = 148 in CHS through 2001). We calculated adjusted hazard ratios (HRs) and their 95% confidence intervals (CIs) for incident VTE in relation to OH status.

RESULTS

In CHS, there was a positive association between OH status and incident VTE (HR for VTE = 1.74 (95% CI: 1.20-2.51)). In contrast, there was no association between OH and VTE in the ARIC study (HR for VTE = 0.97 (95% CI: 0.70-1.33)).

CONCLUSIONS

Community-dwelling older adults with OH had a moderately increased risk of VTE. These results were not seen in a population-based middle-aged cohort.

Intracorneal stromal hemorrhage in dogs and its associations with ocular and systemic disease: 39 cases

OBJECTIVE

To describe clinical features of dogs diagnosed with stromal intracorneal hemorrhage (ICH).

ANIMALS STUDIED

Retrospective case series of 39 dogs (44 eyes) with ICH.

PROCEDURES

Medical records of dogs evaluated by the Cornell University ophthalmology service were searched to identify animals with a clinical diagnosis of ICH between 2005 and 2014. Signalment and clinical details, including concurrent ocular disease, concurrent systemic disease, diagnostic tests performed, outcome of hemorrhage, presenting client complaint, and treatment, were recorded.

RESULTS

Intracorneal hemorrhage was identified in 44 eyes of 39 dogs. The mean (±standard deviation) age of dogs was 11.5 years (±2.8 years). The Bichon Frise breed and older dogs were statistically over-represented relative to the entire ophthalmology service canine referral population during the same time period. Concurrent ocular disease was present in 40 eyes (91%) and included keratoconjunctivitis sicca, cataracts, and corneal ulcers. Twenty-three dogs (59%) suffered from concurrent systemic disease, most frequently diabetes mellitus, hyperadrenocorticism, hypothyroidism, and systemic hypertension. Less commonly, life-threatening systemic conditions were identified in dogs with ICH including immune-mediated hemolytic anemia, immune-mediated thrombocytopenia, metastatic neoplasia, and sepsis. Intracorneal hemorrhage was found in all corneal locations, and corneal vascularization was present in each affected eye.

CONCLUSIONS

Intracorneal hemorrhage is an uncommon condition in dogs that occurs in association with corneal vascularization. The risk of ICH may be increased due to certain ocular and systemic diseases. Although uncommon, ICH may also be an ocular manifestation of severe immune-mediated, infectious, and neoplastic systemic diseases in dogs.

Comorbid risks of deep vein thrombosis and pulmonary thromboembolism in patients with chronic pancreatitis: a nationwide cohort study

ESSENTIALS: Risks of deep vein thrombosis (DVT) and pulmonary embolism (PE) in chronic pancreatitis (CP) are unclear. We conducted a nationwide cohort study to evaluate the risks of DVT and PE in CP patients. 17 778 patients with CP and 71 106 without CP were followed for 86 740 and 429 116 person-years, respectively. Patients with CP had a 2.95-fold increased rate of DVT and a 4.51-fold increased rate of PE.

BACKGROUND

Studies on the association between chronic pancreatitis (CP) and cardiovascular diseases are scarce. We conducted a nationwide cohort study to evaluate the risks of deep vein thrombosis (DVT) and pulmonary embolism (PE) in CP patients.

METHODS

Using the data from the Taiwan National Health Insurance Research Database, we randomly selected a non-CP cohort from insurants without a history of CP, and frequency-matched them at a ratio of 4 : 1 according to age, sex and index year with each patient newly diagnosed with CP between 2000 and 2010. The follow-up period ranged from the index date of new CP diagnosis to the diagnosis of DVT or PE, censoring, or the end of 2011. We used univariable and multivariable Cox proportional hazard regression models to determine the risks of DVT and PE.

RESULTS

In total, 17 778 patients in the CP cohort (82.6% men; mean age of 48.6 years) and 71 106 persons in the non-CP cohort were observed for 86 740 and 429 116 person-years, respectively. The CP cohort showed a 2.95-fold greater adjusted hazard ratio (aHR) for DVT (95% confidence interval [CI] 2.06-4.22) and a 4.51-fold greater aHR for PE (95% CI 2.86-7.11) than the non-CP cohort. Substantial risks of DVT and PE were evident in patients with CP aged < 55 years. The CP cohort with comorbidities showed increased risks of DVT and PE as compared with the non-CP cohort with no comorbidities.

CONCLUSIONS

The risks of DVT and PE are significantly higher in CP patients than in the general population.

Saddle pulmonary embolism: right ventricular strain an indicator for early surgical approach

Current mainstay treatment for pulmonary embolism (PE) includes oral anticoagulation, thrombolytic therapy, catheter embolectomy and acute surgical embolectomy. Surgical embolectomy is reserved for hemodynamically unstable patients (cardiogenic shock, cardiac arrest) and contraindication to thrombolytic therapy. We report a case of saddle PE in a young female with echocardiographic signs of right ventricular (RV) dysfunction who underwent early acute surgical embolectomy with a positive outcome. It would be beneficial to use bedside echocardiography even in hemodynamically stable patients to determine RV strain as this could act as an early indicator suggesting the escalation of therapy.

Plantar Vein Thrombosis: An Unusual Cause of Plantar Pain

We present a case of an 80-year-old man with progressive pain for 5 days at the medial and plantar aspect of the left heel. Wearing shoes aggravated the pain. Ultrasound and magnetic resonance imaging (MRI) revealed thrombosis of the medial plantar veins. Plantar vein thrombosis is a rare condition. The clinical symptoms are non-specific and can be confused with plantar fasciitis. It has been associated with hypercoagulable conditions, foot trauma and recent surgery. The imaging modality of choice is ultrasound. MRI may add to the diagnosis in unclear cases.

Do neutrophil extracellular traps contribute to the heightened risk of thrombosis in inflammatory diseases?

Thrombotic events, both arterial and venous, are a major health concern worldwide. Further, autoimmune diseases, such as systemic lupus erythematosus, anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, and antiphospholipid syndrome, predispose to thrombosis, and thereby push the risk for these morbid events even higher. In recent years, neutrophils have been identified as important players in both arterial and venous thrombosis. Specifically, chromatin-based structures called neutrophil extracellular traps (NETs) play a key role in activating the coagulation cascade, recruiting platelets, and serving as scaffolding upon which the thrombus can be assembled. At the same time, neutrophils and NETs are emerging as important mediators of pathogenic inflammation in the aforementioned autoimmune diseases. Here, we first review the general role of NETs in thrombosis. We then posit that exaggerated NET release contributes to the prothrombotic diatheses of systemic lupus erythematosus, ANCA-associated vasculitis, and antiphospholipid syndrome.

Histopathological Differences of the Pedicle Artery in Commonly Used Free Flaps: The Influence of Age, Gender, and Side

PURPOSE

The increasing use of vascularized free flaps has increased the demand for a specified flap selection. This study investigated histologic differences in the arterial wall of the pedicle for commonly used free flaps and the effect of age, gender, and anatomic side on these differences.

MATERIALS AND METHODS

Light microscopic examinations of vessel walls were performed on 245 specimens of the nourishing artery of commonly used free vascularized flaps in preserved cadavers. The peroneal artery (PA), radial artery (RA), inferior epigastric artery (IEA), deep circumflex iliac artery (DCIA), and circumflex scapular artery (CSA) were examined. Differences of histologic changes in the arterial wall and the effect of age, gender, and body side were investigated.

RESULTS

All examined vessel specimens (age range, 62 to 98 yr; mean age, 83 yr; 15 female and 12 male) displayed mostly Class II changes. PA showed the greatest atherosclerotic changes, followed by the RA, IEA, DCIA, and CSA. Age had a meaningful effect on PA and RA. Anatomic side was important for PA and DCIA, whereas gender had a minor influence on vessel condition.

CONCLUSION

The vessel wall of different flaps showed different atherosclerotic changes depending on age, anatomic side, and gender. These differences should be considered in flap selection.

Multiple sclerosis increases the risk of venous thromboembolism: a nationwide cohort analysis

OBJECTIVES

The purpose of this study was to evaluate the effects of multiple sclerosis (MS) on the risk of venous thromboembolism (VTE) development.

METHODS

We identified patients diagnosed with MS in Taiwan between 1998 and 2010 using the National Health Insurance Research Database and the Catastrophic Illness Patient Database (RCIPD). Each MS patient was frequency matched to 4 controls according to age, sex and the year of MS registration to the RCIPD. Patients with a history of VTE and incomplete information of age and sex were excluded. All patients were followed up from the index year until VTE diagnosis, loss to follow-up or the end of 2010. We calculated the hazard ratios (HRs) and 95% confidence intervals (CIs) of VTE in the MS and comparison cohorts using Cox proportional hazards regression models.

RESULTS

We followed up 1238 MS patients and 4952 comparison patients for approximately 6437 and 27 595 person-years, respectively. After adjusting for age, sex and comorbidities, the MS patients exhibited a 6·87-fold increased risk of VTE compared with the control patients. Women with MS were associated with an 11·1-fold increased risk of VTE development compared with the non-MS women (95% CI: 2·70-45·5). The MS patients aged < 50 years exhibited a 14·8-fold increased risk of developing VTE compared with age-matched patients in the comparison cohort (95% CI: 2·99-73·4). The risk of VTE development increased with the duration of hospitalization stay.

CONCLUSION

MS patients are associated with significantly greater risk of developing VTE compared with non-MS patients.

VEGFR2 Gene Polymorphism Correlates with Deep Venous Thrombosis Risk in Chinese Han Population

OBJECTIVE

To investigate the correlations between three vascular endothelial growth factor 2 (VEGFR2) gene polymorphisms, +1192C>T, +1719T>A, and -604T>C, and deep venous thrombosis (DVT) in Chinese Han population.

METHODS

We conducted a case-control study, between September 2009 and September 2012, in a Chinese Han population with onset of lower extremity DVT. A total of 135 patients were enrolled in the case group and 156 healthy individuals in the control group. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to detect the genotype and allele frequencies of the VEGFR2 gene polymorphisms +1192C>T, +1719T>A, and -604T>C. Haplotype analyses were conducted with SHEsis program. Logistic regression was used to detect the risk factors of DVT. Outpatient review and telephone follow-up were conducted to analyze the long-term treatment of DVT patients.

RESULTS

The allele and genotype frequencies of -604T>C VEGFR2 polymorphism exhibited significant differences between the case and control groups (both p < 0.05). Haplotype analyses showed remarkable differences between the case and control groups in the distribution frequency of TAC and CTT haplotypes in the VEGFR2 gene (both p < 0.05). Logistic regression analysis showed independent correlation between the incidence of DVT and TAC haplotype in the VEGFR2 gene (p < 0.05). In addition, the TAC haplotype may be a risk factor for DVT treatment failure.

CONCLUSION

Our findings suggest that the VEGFR2 gene -604T>C polymorphism and TAC haplotype are associated with DVT, and the TAC haplotype might affect the efficacy of long-term treatment of DVT patients.

Genetic risk factors in patients with deep venous thrombosis, a retrospective case control study on Iranian population

Background

Venous thromboembolism (VTE) could be manifested as deep venous thrombosis (DVT) or pulmonary embolism (PE). DVT is usually the more common manifestation and is usually formation of a thrombus in the deep veins of lower extremities. DVT could occur without known underlying cause (idiopathic thrombosis) which could be a consequence of an inherited underlying risk factor or could be a consequence of provoking events, such as trauma, surgery or acute illness (provoked thrombosis). Our aim in this study was to assess the impact of some previously reported genetic risk factors including, methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, plasminogen activator inhibitor-1(PAI-1) 4G/5G, prothrombin 20210 and FV Leiden on occurrence of DVT in a population of Iranian patients.

Methods

This long-term study was conducted on 182 patients with DVT and also 250 age and sex matched healthy subjects as control group. The diagnosis of DVT was based on patient’s history, clinical findings, D-dimer test, and confirmed by Doppler ultrasonography. After confirmation of DVT, both groups were assessed for the five mentioned mutations. The relationship between mutations and predisposition to DVT was calculated by using logistic regression and expressed as an OR with a 95 % confidence interval (CI).

Results

Our results revealed that FV Leiden (OR 6.7; 95 % CI = 2.2 to 20.3; P = 0.001), MTHFR C677T (OR 6.0; 95 % CI = 2.2 to 16.4; P < 0.001), MTHFR A1298C (OR 8.3; 95 % CI = 4.4 to 15.8; P < 0.001), and PAI-1 4G/5G (OR 3.8; 95 % CI = 2.1 to 7.2; P < 0.001) mutations were all significantly associated with an increased risk of DVT. Prothrombin 20210 was found in none of the patients and controls.

Conclusion

Our findings suggest that genetic risk factors have a contributory role on occurrence of DVT.

Seeing through thick and through thin: Retinal manifestations of thrombophilic and hyperviscosity syndromes

The presence of retinal vasculopathy in the absence of typical predisposing factors should suggest a possible underlying hematologic abnormality. In such cases, a systemic investigation may reveal a potentially fatal hypercoagulability or hyperviscosity syndrome. Retinal vein occlusion is the most commonly encountered ophthalmic finding in such syndromes; however, abnormalities of the arterial system, the choroid, and the macula are also possible. Visual symptoms may be the only manifestation of the underlying process, making timely diagnosis by the ophthalmologist critical for both treatment and thrombotic prophylaxis. Moreover, as newer ophthalmic diagnostic technologies arise, there is an increasingly important role for eye physicians in the management of such syndromes.

Imaging Findings of Liposuction with an Emphasis on Postsurgical Complications

Liposuction is one of the most frequently performed cosmetic surgeries worldwide for reshaping the body contour. Although liposuction is minimally invasive and relatively safe, it is a surgical procedure, and it carries the risk of major and minor complications. These complications vary from postoperative nausea to life-threatening events. Common complications include infection, abdominal wall injury, bowel herniation, bleeding, haematoma, seroma, and lymphoedema. Life-threatening complications such as necrotizing fasciitis, deep vein thrombosis, and pulmonary embolism have also been reported. In this paper, we provide a brief introduction to liposuction with the related anatomy and present computed tomography and ultrasonography findings of a wide spectrum of postoperative complications associated with liposuction.

Adverse effects of glucocorticoids: coagulopathy

Hypercortisolism is associated with various systemic manifestations, including central obesity, arterial hypertension, glucose intolerance/diabetes mellitus, dyslipidemia, nephrolithiasis, osteoporosis, gonadal dysfunction, susceptibility to infections, psychiatric disorders, and hypercoagulability. The activation of the hemostatic system contributes to the development of atherosclerosis and subsequent cardiovascular morbidity and mortality. Previous studies have identified an increased risk of both unprovoked and postoperative thromboembolic events in patients with endogenous and exogenous Cushing's syndrome (CS). The risk for postoperative venous thromboembolism in endogenous CS is comparable to the risk after total hip or knee replacement under short-term prophylaxis. The mechanisms that are involved in the thromboembolic complications in hypercortisolism include endothelial dysfunction, hypercoagulability, and stasis (Virchow's triad). It seems that at least two factors from Virchow's triad must be present for the occurrence of a thrombotic event in these patients. Most studies have demonstrated that this hypercoagulable state is explained by increased levels of procoagulant factors, mainly factors VIII, IX, and von Willebrand factor, and also by an impaired fibrinolytic capacity, which mainly results from an elevation in plasminogen activator inhibitor 1. Consequently, there is a shortening of activated partial thromboplastin time and increased thrombin generation. For these reasons, anticoagulant prophylaxis might be considered in patients with CS whenever they have concomitant prothrombotic risk factors. However, multicenter studies are needed to determine which patients will benefit from anticoagulant therapy and the dose and time of anticoagulation.

Diabetes increases the risk of deep-vein thrombosis and pulmonary embolism. A population-based cohort study

We evaluated the effects of diabetes on the risks of developing deep-vein thrombosis (DVT) and pulmonary embolism (PE) in a nationwide, population-based cohort study in Taiwan. The patients with newly diagnosed type 2 diabetes mellitus (T2DM) were identified, and DM-free controls were randomly selected from the general population and frequency-matched according to age, sex, and index year by using the records of the Longitudinal Health Insurance Database between 2000 and 2011. Both cohorts were followed up until the end of 2011 to measure the incidence of DVT and PE. We analysed the risks of DVT and PE using Cox proportional-hazards regression models. The overall incidence of VTE was higher in the T2DM patients than in the controls (12.0 vs 7.51 per 10,000 person-years). The T2DM patients exhibited a 1.44-fold adjusted hazard ratio (aHR) of VTE development compared with the controls (95% confidence interval [CI] = 1.27-1.63). The risks of DVT (aHR = 1.43, 95% CI = 1.23-1.65) and PE (aHR = 1.52, 95% CI = 1.22-1.90) were greater in the T2DM than those in the controls. The T2DM patients had a substantially higher risk of DVT (aHR = 5.10, 95% CI = 3.12-8.32) and PE (aHR = 7.50, 95% CI = 3.29-17.1) development than the controls did in adults aged 49 years and younger. In conclusion, the longitudinal nationwide cohort study indicated that T2DM patients carried greater risks of developing VTE than did the general population.

Inferior vena cava occlusion causing syncope during upper extremity exertion treated with iliocaval venous revascularization

Inferior vena cava (IVC) thrombosis is rare, but its incidence is increased in those with IVC filters or inflammatory bowel disease. Once the IVC is thrombosed, venous return is via collateral channels on the torso and retroperitoneum. Limitations in this collateral venous return can result in symptoms, usually in the lower extremities. Syncope and dyspnea are rare. We report a patient with a 1-year history of worsening syncope when working with his upper extremities. Iliocaval venous occlusion with lack of accommodation of venous return at the thoracic outlet was diagnosed. Treatment with iliocaval stenting resolved his symptoms.

Characterization of mice harboring a variant of EPCR with impaired ability to bind protein C: novel role of EPCR in hematopoiesis

Mutation of the PC-binding domain of EPCR results in viable mice that exhibit procoagulant and proinflammatory phenotype when challenged. EPCRR84A/R84A mice develop splenomegaly as a result of BM failure, suggesting that EPCR plays an important role in hematopoiesis.