Hypercoagulable states

Venous thromboembolism in viral diseases: A comprehensive literature review

Venous thromboembolism (VTE) is known to be a common respiratory and/or cardiovascular complication in hospitalized patients with viral infections. Numerous studies have proven human immunodeficiency virus infection to be a prothrombotic condition. An elevated VTE risk has been observed in critically ill H1N1 influenza patients. VTE risk is remarkably higher in patients infected with the Hepatitis C virus in contrast to uninfected subjects. The elevation of D-dimer levels supported the association between Chikungunya and the Zika virus and the rise of clinical VTE risk. Varicella-zoster virus is a risk factor for both cellulitis and the consequent invasive bacterial disease which may take part in thrombotic initiation. Eventually, hospitalized patients infected with the coronavirus disease of 2019 (COVID-19), the cause of the ongoing worldwide pandemic, could mainly suffer from an anomalous risk of coagulation activation with enhanced venous thrombosis events and poor quality clinical course. Although the risk of VTE in nonhospitalized COVID-19 patients is not known yet, there are a large number of guidelines and studies on thromboprophylaxis administration for COVID-19 cases. This study aims to take a detailed look at the effect of viral diseases on VTE, the epidemiology of VTE in viral diseases, and the diagnosis and treatment of VTE.

Detection of Exon 10 Mutation (rs6020) in Factor V Gene in Sudanese patients with Deep Vein Thrombosis.. [DOI: 10.21203/rs.3.rs-2500709/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background: Deep vein thrombosis (DVT), a subgroup of venous thromboembolism (VTE), is one of the leading causes of morbidity and mortality globally, accounting for 60,000-100,000 fatalities per year. It affects around 0.1 percent of the population each year. In Sudanese patients with DVT, this study looked for probable harmful single nucleotide polymorphisms in exon 10 of the factor V gene. Method: Thirty blood samples were obtained from previously diagnosed DVT patients at Omdurman teaching hospital throughout the period of 16 August to 25 October 2018, as part of a descriptive cross-sectional research in Khartoum state. Exon 10 was amplified by PCR using sequence-specific primers after DNA was extracted using the guanidine chloride procedure. The fifteen best bands' PCR products were sequenced in both directions (BGI Company). Bioinformatics techniques were used to examine the sequences (Finch TV, BLAST, and Codon Code alignment). Result: The presence of a missense mutation (rs6020) in the factor V Leiden gene was discovered in 40% (6/15) of the patients in this investigation. In five cases, this mutation was heterozygous, whereas in one patient, it was homozygous. In the other nine cases, no mutations were found. Conclusion: rs6020 is more prevalent in the Sudanese population than other types of mutations. rs6020 polymorphism has a strong association with deep vein thrombosis in the Sudanese population. Further investigation of this mutation amongst larger Sudanese population is required in order to support this finding as well as to understand its clinical significance.

Role of von Willebrand factor in venous thromboembolic disease

Objective

Evolving evidence of the shared risk factors and pathogenic mechanisms in arterial and venous thrombosis questions of the strict vascular dichotomy of arterial vs venous. The connection between arterial and venous thrombosis has been highlighted by common underlying inflammatory processes, a concept known as thromboinflammatory disease. Using this relationship, we can apply knowledge from arterial disease to better understand and potentially mitigate venous disease. A protein that has been extensively studied in atherothrombotic disease and inflammation is von Willebrand factor (VWF). Because many predisposing and provoking factors of venous thromboembolism (VTE) have been shown to directly modulate VWF levels, it is, perhaps, not surprising that VWF has been highlighted by several recent association studies of patients with VTE.

Methods

In the present narrative review, we investigated more deeply the effects of VWF in venous disease by synthesizing the data from clinical studies of deep vein thrombosis of the limbs, pulmonary embolism, portal and cerebral vein thrombosis, and the complications of thrombosis, including post-thrombotic syndrome, venous insufficiency, and chronic thromboembolic pulmonary hypertension. We have also discussed the findings from preclinical studies to highlight novel VWF biochemistry in thrombosis and therapeutics.

Results

Across the spectrum of venous thromboembolic disease, we consistently observed that elevated VWF levels conferred an increased risk of VTE and long-term venous complications. We have highlighted important findings from VWF molecular research and have proposed mechanisms by which VWF participates in venous disease. Emerging evidence from preclinical studies might reveal novel targets for thromboinflammatory disease, including specific VWF pathophysiology. Furthermore, we have highlighted the utility of measuring VWF to prognosticate and risk stratify for VTE and its complications.

Conclusions

As the prevalence of inflammatory processes, such as aging, obesity, and diabetes increases in our population, it is critical to understand the evolving role of VWF in venous disease to guide clinical decisions and therapeutics.

Therapeutic Efficacy of Antioxidants in Ameliorating Obesity Phenotype and Associated Comorbidities

Obesity has been a worldwide epidemic for decades. Despite the abundant increase in knowledge regarding the etiology and pathogenesis of obesity, the prevalence continues to rise with estimates predicting considerably higher numbers by the year 2030. Obesity is characterized by an abnormal lipid accumulation, however, the physiological consequences of obesity are far more concerning. The development of the obesity phenotype constitutes dramatic alterations in adipocytes, along with several other cellular mechanisms which causes substantial increase in systemic oxidative stress mediated by reactive oxygen species (ROS). These alterations promote a chronic state of inflammation in the body caused by the redox imbalance. Together, the systemic oxidative stress and chronic inflammation plays a vital role in maintaining the obese state and exacerbating onset of cardiovascular complications, Type II diabetes mellitus, dyslipidemia, non-alcoholic steatohepatitis, and other conditions where obesity has been linked as a significant risk factor. Because of the apparent role of oxidative stress in the pathogenesis of obesity, there has been a growing interest in attenuating the pro-oxidant state in obesity. Hence, this review aims to highlight the therapeutic role of antioxidants, agents that negate pro-oxidant state of cells, in ameliorating obesity and associated comorbidities. More specifically, this review will explore how various antioxidants target unique and diverse pathways to exhibit an antioxidant defense mechanism.

D-Dimer level was associated with prognosis in metastatic colorectal cancer: A Chinese patients based cohort study

D-dimer level is a direct measure of activated coagulation and has been used as a biomarker of hypercoagulability. In this study, we aimed to explore the associations between D-dimer level and the clinicopathological features and prognosis in metastatic colorectal cancer (mCRC) patients. One hundred seventy-eight patients diagnosed with mCRC from the Department of General Surgery, Jingmen First People's Hospital from September 2014 to December 2018 were collected. Data of coagulation index was evaluated and survival analysis was performed to identify the biomarker of mCRC. Among 178 cases of colorectal cancer, we found that the value of 0.55 mg/L, 5ng/ml and 40U/ml were cut-off values of D-Dimer, CEA and CA-199 for patients survival, respectively. hypercoagulability was much more frequent in patients aged ≥60 years than <60 years (P < .001) and also in patients with ECOG ≥2 points (P < .001). Moreover, those patients who have CEA >5ng/ml and CA-199>40U/ml had hypercoagulable state (P < .001). There was a significant difference in D-Dimer >0.55 mg/L and D-Dimer ≤0.55 mg/L among the number of metastatic sites (P < .01) and patients with comorbidities (P < .01). Survival analysis showed that patients with D-Dimer >0.55 mg/L have significantly unfavorable overall survival (P = .006) and progressive free survival (P = .011).

Below-Knee Amputation Resulting from an Arterial Thrombosis from Tourniquet Use in a Patient with Undiagnosed Factor V Leiden: A Case Report

CASE

A 38-year-old woman presented with previously undiagnosed factor V Leiden (FVL), who suffered a complete superficial femoral arterial thrombosis after tourniquet use during the surgical repair of one of her bilateral tibial plafond fractures. This patient's injury eventually resulted in a below-knee amputation.

CONCLUSION

We recommend expanding hypercoagulable screening on patients with risk factors based on a detailed history and physical examination. We also recommend limiting or negating tourniquet use in patients with FVL or other hypercoagulable disorders.

A specific controlled ovarian stimulation (COS) protocol for fertility preservation in women with breast cancer undergoing neoadjuvant chemotherapy

Aim of the study

The authors present a novel and specific controlled ovarian stimulation protocol for fertility preservation in women with estrogen-positive receptor breast cancer undergoing neoadjuvant chemotherapy. The protocol foresees random start ovarian stimulation and the use of letrozole associated to tamoxifen.

Material and methods

Forty breast cancer patients were included in the study. COS was performed either with recombinant FSH or hMG. Concomitantly with COS, letrozole in a dose of 5 mg and tamoxifen in a dose of 20 mg were given orally on a daily basis. The trigger was performed with 0.2 mg of triptorelin, in the presence of follicles ≥ 19 mm. Oocyte retrieval was scheduled 35-36 hours after triptorelin injection. Our main outcome measures were the number of oocytes collected and number of oocytes vitrified, the length of ovarian stimulation, total dose of gonadotropins administered, and levels of estradiol on the day of the trigger.

Results

The mean age of patients was 30.43 ±4.25 years. Nineteen women commenced COS in the luteal phase, eleven in the early follicular phase and ten in the late follicular phase. The mean number of collected oocytes was 11.78 ±9.12 and the mean number of vitrified oocytes was 9.72 ±7.36. The mean duration of COS was 10.03 ±1.33 days. The mean estradiol concentrations on the triggering day was 623.10 ±441.27, and the mean dose of gonadotropins administered was 2540 ±713.10.

Conclusions

The authors suggest that the protocol is efficient and may be a safe option for oocyte vitrification in these patients.

Controversies in Microvascular Maxillofacial Reconstruction

The effectiveness and reliability of microvascular reconstruction for large defects in the head and neck is no longer disputed. However, many controversies still persist in the ideal perioperative management of patients undergoing free tissue transfer. The optimal method of postoperative monitoring, the use of vasoconstrictors in the perioperative period, and the use of anticoagulants in the postoperative period remain topics of debate. This article offers recommendations on each of these controversies based on a review of the current literature.

Increasing confidence and changing behaviors in primary care providers engaged in genetic counselling

BACKGROUND

Screening and counseling for genetic conditions is an increasingly important part of primary care practice, particularly given the paucity of genetic counselors in the United States. However, primary care physicians (PCPs) often have an inadequate understanding of evidence-based screening; communication approaches that encourage shared decision-making; ethical, legal, and social implication (ELSI) issues related to screening for genetic mutations; and the basics of clinical genetics. This study explored whether an interactive, web-based genetics curriculum directed at PCPs in non-academic primary care settings was superior at changing practice knowledge, attitudes, and behaviors when compared to a traditional educational approach, particularly when discussing common genetic conditions.

METHODS

One hundred twenty one PCPs in California and Pennsylvania physician practices were randomized to either an Intervention Group (IG) or Control Group (CG). IG physicians completed a 6 h interactive web-based curriculum covering communication skills, basics of genetic testing, risk assessment, ELSI issues and practice behaviors. CG physicians were provided with a traditional approach to Continuing Medical Education (CME) (clinical review articles) offering equivalent information.

RESULTS

PCPs in the Intervention Group showed greater increases in knowledge compared to the Control Group. Intervention PCPs were also more satisfied with the educational materials, and more confident in their genetics knowledge and skills compared to those receiving traditional CME materials. Intervention PCPs felt that the web-based curriculum covered medical management, genetics, and ELSI issues significantly better than did the Control Group, and in comparison with traditional curricula. The Intervention Group felt the online tools offered several advantages, and engaged in better shared decision making with standardized patients, however, there was no difference in behavior change between groups with regard to increases in ELSI discussions between PCPs and patients.

CONCLUSION

While our intervention was deemed more enjoyable, demonstrated significant factual learning and retention, and increased shared decision making practices, there were few differences in behavior changes around ELSI discussions. Unfortunately, barriers to implementing behavior change in clinical genetics is not unique to our intervention. Perhaps the missing element is that busy physicians need systems-level support to engage in meaningful discussions around genetics issues. The next step in promoting active engagement between doctors and patients may be to put into place the tools needed for PCPs to easily access the materials they need at the point-of-care to engage in joint discussions around clinical genetics.

The value of postoperative anticoagulants to improve flap survival in the free radial forearm flap: a systematic review and retrospective multicentre analysis

BACKGROUND

Free radial forearm flap (FRFF) reconstruction is a valuable technique in head and neck surgery, which allows closure of large defects while striving to maintain functionality. Anticoagulative drugs are often administered to improve flap survival, although evidence regarding effectiveness is lacking.

OBJECTIVE OF REVIEW

To investigate the effectiveness of postoperative anticoagulants to improve survival of the FRFF in head and neck reconstruction.

TYPE OF REVIEW

Systematic review and multicentre, individual patient data meta-analysis.

SEARCH STRATEGY

MEDLINE, EMBASE, Web of Science and CINAHL were searched for synonyms of 'anticoagulants' and 'free flap reconstruction'.

EVALUATION METHOD

Studies were critically appraised for directness of evidence and risk of bias. Authors of the highest quality publications were invited to submit their original data for meta-analysis.

RESULTS

Five studies were of adequate quality, and data from four studies (80%) were available for meta-analysis, describing 759 FRFF procedures. Anticoagulants used were as follows: aspirin (12%), low molecular weight dextran (18.3%), unfractioned heparin (28.1%), low molecular weight heparin (49%) and prostaglandin-E1 (2.1%). Thirty-one per cent did not receive anticoagulants. Flap failure occurred in 40 of 759 patients (5.3%) On univariate analysis, use of unfractioned heparin was associated with a higher rate of flap failure. However, these regimens were often administered to patients who had revision surgery of the anastomosis. In multivariate logistic regression analysis, anticoagulant use was not associated with improved flap survival or flap-related complications.

CONCLUSIONS

The studied anticoagulative drugs did not improve FRFF survival or lower the rate of flap-related complications. In addition, some anticoagulants may cause systemic complications.

The simultaneous occurrence of both hypercoagulability and hypofibrinolysis in blood and serum during systemic inflammation, and the roles of iron and fibrin(ogen)

Although the two phenomena are usually studied separately, we summarise a considerable body of literature to the effect that a great many diseases involve (or are accompanied by) both an increased tendency for blood to clot (hypercoagulability) and the resistance of the clots so formed (hypofibrinolysis) to the typical, 'healthy' or physiological lysis. We concentrate here on the terminal stages of fibrin formation from fibrinogen, as catalysed by thrombin. Hypercoagulability goes hand in hand with inflammation, and is strongly influenced by the fibrinogen concentration (and vice versa); this can be mediated via interleukin-6. Poorly liganded iron is a significant feature of inflammatory diseases, and hypofibrinolysis may change as a result of changes in the structure and morphology of the clot, which may be mimicked in vitro, and may be caused in vivo, by the presence of unliganded iron interacting with fibrin(ogen) during clot formation. Many of these phenomena are probably caused by electrostatic changes in the iron-fibrinogen system, though hydroxyl radical (OH˙) formation can also contribute under both acute and (more especially) chronic conditions. Many substances are known to affect the nature of fibrin polymerised from fibrinogen, such that this might be seen as a kind of bellwether for human or plasma health. Overall, our analysis demonstrates the commonalities underpinning a variety of pathologies as seen in both hypercoagulability and hypofibrinolysis, and offers opportunities for both diagnostics and therapies.

Impact of a randomized controlled educational trial to improve physician practice behaviors around screening for inherited breast cancer

BACKGROUND

Many primary care physicians (PCPs) are ill-equipped to provide screening and counseling for inherited breast cancer.

OBJECTIVE

To evaluate the outcomes of an interactive web-based genetics curriculum versus text curriculum for primary care physicians.

DESIGN

Randomized two-group design.

PARTICIPANTS

121 California and Pennsylvania community physicians.

INTERVENTION

Web-based interactive genetics curriculum, evaluated against a control group of physicians who studied genetics review articles. After education, physicians interacted with an announced standardized patient (SP) at risk for inherited breast cancer.

MAIN MEASURES

Transcripts of visit discussions were coded for presence or absence of 69 topics relevant to inherited breast cancer.

KEY RESULTS

Across all physicians, history-taking, discussions of test result implications, and exploration of ethical and legal issues were incomplete. Approximately half of physicians offered a genetic counseling referral (54.6%), and fewer (43.8%) recommended testing. Intervention physicians were more likely than controls to explore genetic counseling benefits (78.3% versus 60.7%, P = 0.048), encourage genetic counseling before testing (38.3% versus 21.3%, P = 0.048), ask about a family history of prostate cancer (25.0% versus 6.6%, P = 0.006), and report that a positive result indicated an increased risk of prostate cancer for male relatives (20.0% versus 1.6%, P = 0.001). Intervention-group physicians were less likely than controls to ask about Ashkenazi heritage (13.3% versus 34.4%, P = 0.01) or to reply that they would get tested when asked, "What would you do?" (33.3% versus 54.1%, P = 0.03).

CONCLUSIONS

Physicians infrequently performed key counseling behaviors, and this was true regardless of whether they had completed the web-based interactive training or read clinical reviews.

Cerebral venous thrombosis in a breast cancer patient taking tamoxifen: Report of a case

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Tamoxifen could increase the risk for venous thromboembolic complications.

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Clinicians should concern the possibility of thrombotic event with tamoxifen.

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In high-risk patients, new aromatase inhibitors might be considered alternative.

Introduction

Tamoxifen reduces breast cancer risk, but can cause thromboembolic complications. Cerebral venous thrombosis is a rare form of stroke in which blood clots occlude the dural sinus or cerebral veins.

Presentation of case

A 46-year old female presented with a severe headache and nausea of subacute onset. She had undergone masectomy for breast cancer 20 months ago and had been taking tamoxifen. Brain CT and MRI confirmed cerebral venous infarction and venous thrombosis in the superior sagittal sinus and straight sinus. She had elevated D-dimer level, decreased levels of protein S activity and antithrombin III. Doppler ultrasound revealed concurrent deep vein thrombosis in her right leg. There was no evidence of breast cancer recurrence. With oral anticoagulation, she discharged without neurological complications. The abnormal laboratory findings of coagulopathy returned to normal after discontinuation of tamoxifen.

Discussion

Considering the abnormal findings in the workup of coagulopathy and no other risk factor for venous thrombosis, this thromboembolic complication can be attributed to the coagulopathy with use of tamoxifen.

Conclusion

Clinicians should warn about the possibility of thromboembolic complications with tamoxifen.

Modeling thrombin generation: plasma composition based approach

Thrombin has multiple functions in blood coagulation and its regulation is central to maintaining the balance between hemorrhage and thrombosis. Empirical and computational methods that capture thrombin generation can provide advancements to current clinical screening of the hemostatic balance at the level of the individual. In any individual, procoagulant and anticoagulant factor levels together act to generate a unique coagulation phenotype (net balance) that is reflective of the sum of its developmental, environmental, genetic, nutritional and pharmacological influences. Defining such thrombin phenotypes may provide a means to track disease progression pre-crisis. In this review we briefly describe thrombin function, methods for assessing thrombin dynamics as a phenotypic marker, computationally derived thrombin phenotypes versus determined clinical phenotypes, the boundaries of normal range thrombin generation using plasma composition based approaches and the feasibility of these approaches for predicting risk.

Acquired Thrombophilia

Acquired thrombophilia is associated with an increased risk of venous thromboembolism (VTE). Antiphospholipid syndrome (APS) is the most prevalent acquired thrombophilia and is associated with both venous and arterial thromboses. Human immunodeficiency virus (HIV) is another form of acquired thrombophilia. Risk factors associated with VTE in this population include those related to the disease itself, host factors, and the pharmacotherapy for HIV. A significant proportion of VTE events occur in patients with malignancies. There is an increase in mortality associated with patients having cancer who experience VTE when compared to patients having cancer without VTE. Combination oral contraceptive (COC) use infers risk of thromboembolic events. The risk is dependent upon the presence of an underlying inherited thrombophilia, the estrogen dose, and generation of progestin. Patients at highest risk of VTE include those receiving high-dose estrogen and fourth-generation, progesterone-containing contraceptives. With the exception of APS, thrombophilia status does not alter the acute treatment of an initial VTE in nonpregnant patients.

Treatment with Huisheng oral solution inhibits the development of pulmonary thromboembolism and metastasis in mice with Lewis lung carcinoma

The aim of this study was to investigate whether Huisheng oral solution (HSOS) has an inhibitory effect on the development of pulmonary thrombosis and metastasis in mice with Lewis lung carcinoma (LLC), and to explore the possible mechanisms involved. A mouse model of LLC was developed, and model mice were divided into either a treatment group or a control group to undergo treatment with HSOS or normal saline. Normal mice treated with saline were used as normal controls. On day 25 after treatment, blood samples were drawn from the eyes of half the mice in each group to determine blood cell counts and plasma levels of D-Dimer and vascular endothelial growth factor (VEGF), while heart blood samples were collected from the remaining mice to measure the rate of thrombin-induced platelet aggregation. For all mice, pathological analyses of the cerebrum, lung, mesentery, femoral vein, external iliac vein and spleen were performed. Tumors were weighed to assess the impact of HSOS treatment on tumor growth, and the number of thrombi, metastatic nodules and neovessels in the tumor tissue were counted. In addition, 24 normal New Zealand rabbits were divided into two groups and treated with either HSOS or normal saline to determine the rates of ADP-, collagen- or thrombin-induced platelet aggregation. Compared with the model group, HSOS treatment decreased the incidence of pulmonary thromboembolism and metastasis, the number of metastatic nodules, the plasma levels of D-dimer and VEGF, the rate of collagen-induced platelet aggregation in rabbits and the numbers of leukocytes and tumor neovessels (P<0.05 for all). It increased the thymus and spleen coefficients and the number of platelets (P<0.05 for all), but had no significant effect on thrombin-induced platelet aggregation in mice and rabbits, ADP-induced platelet aggregation in rabbits, or the number of red blood cells. The reduced rate of tumor growth was 9.7% in mice treated with HSOS. HSOS treatment effectively reduced the development of pulmonary thromboembolism and metastasis in mice bearing LLC via mechanisms possibly associated with ameliorating a blood hypercoagulable state, decreasing tumor angiogenesis and enhancing immunity.

Interaction between bone morphogenetic protein receptor type 2 and estrogenic compounds in pulmonary arterial hypertension

Abstract The majority of heritable pulmonary arterial hypertension (HPAH) cases are associated with mutations in bone morphogenetic protein receptor type 2 (BMPR2). BMPR2 mutation carries about a 20% lifetime risk of PAH development, but penetrance is approximately three times higher in females. Previous studies have shown a correlation between estrogen metabolism and penetrance, with increased levels of the estrogen metabolite 16α-hydroxyestrone (16αOHE) and reduced levels of the metabolite 2-methoxyestrogen (2ME) associated with increased risk of disease. The goal of this study was to determine whether 16αOHE increased and 2ME decreased penetrance of disease in Bmpr2 mutant mice and, if so, by what mechanism. We found that 16αOHE∶2ME ratio was high in male human HPAH patients. Bmpr2 mutant male mice receiving chronic 16αOHE had doubled disease penetrance, associated with reduced cardiac output. 2ME did not have a significant protective effect, either alone or in combination with 16αOHE. In control mice but not in Bmpr2 mutant mice, 16αOHE suppressed bone morphogenetic protein signaling, probably directly through suppression of Bmpr2 protein. Bmpr2 mutant pulmonary microvascular endothelial cells were insensitive to estrogen signaling through canonical pathways, associated with aberrant intracellular localization of estrogen receptor α. In both control and Bmpr2 mutant mice, 16αOHE was associated with suppression of cytokine expression but with increased alternate markers of injury, including alterations in genes related to thrombotic function, angiogenesis, planar polarity, and metabolism. These data support a causal relationship between increased 16αOHE and increased PAH penetrance, with the likely molecular mechanisms including suppression of BMPR2, alterations in estrogen receptor translocation, and induction of vascular injury and insulin resistance-related pathways.

Models for thrombin generation and risk of disease

Computational models can offer an integrated view of blood clotting dynamics and may ultimately be instructive regarding an individual's risk of bleeding or clotting. Appropriately, developed and validated models could allow clinicians to simulate the outcomes of therapeutics and estimate risk of disease. Computational models that describe the dynamics of thrombin generation have been developed and have been used in combination with empirical studies to understand thrombin dynamics on a mechanistic basis. The translation of an individual's specific coagulation factor composition data using these models into an integrated assessment of hemostatic status may provide a route for advancing the long-term goal of individualized medicine. This review details the integrated approaches to understanding: (i) What is normal thrombin generation in individuals? (ii) What is the effect of normal range plasma composition variation on thrombin generation in pathologic states? (iii) Can disease progression or anticoagulation be followed by understanding the boundaries of normal thrombin generation defined by plasma composition? (iv) What are the controversies and limitations of current computational approaches? Progress in these areas can bring us closer to developing models that can be used to aid in identifying hemostatic risk.

Gender, sex hormones and pulmonary hypertension

Most subtypes of pulmonary arterial hypertension (PAH) are characterized by a greater susceptibility to disease among females, although females with PAH appear to live longer after diagnosis. While this "estrogen paradoxȍ of enhanced female survival despite increased female susceptibility remains a mystery, recent progress has begun to shed light upon the interplay of sex hormones, the pathogenesis of pulmonary hypertension, and the right ventricular response to stress. For example, emerging data in humans and experimental models suggest that estrogens or differential sex hormone metabolism may modify disease risk among susceptible subjects, and that estrogens may interact with additional local factors such as serotonin to enhance the potentially damaging chronic effects of estrogens on the pulmonary vasculature. Regardless, it remains unclear why not all estrogenic compounds behave equally, nor why estrogens appear to be protective in certain settings but detrimental in others. The contribution of androgens and other compounds, such as dehydroepiandrosterone, to pathogenesis and possibly treatment must be considered as well. In this review, we will discuss the recent understandings on how estrogens, estrogen metabolism, dehydroepiandrosterone, and additional susceptibility factors may all contribute to the pathogenesis or potentially to the treatment of pulmonary hypertension, by evaluating current human, cell-based, and experimental model data.

Diagnostic approach to deep venous thrombosis and pulmonary embolism in the critical care setting

Considerable progress has been made during the last 30 years in the prevention, diagnosis, and therapy of venous thromboembolism. This article discusses the epidemiology, pathophysiology, and clinical presentation of the disease as well as the diagnostic uncertainty that exists in the critical care setting. Diagnostic approaches for deep venous thrombosis and pulmonary embolism are considered, including clinical prediction rules, D-dimer, contrast venography, duplex ultrasonography, computed tomographic angiography and venography, magnetic resonance imaging, ventilation–perfusion scanning, chest radiograph, arterial blood gases, electrocardiography, and echocardiography.

Experimental Validation of Methods for Prophylaxis against Deep Venous Thrombosis: A Review and Proposal

The experimental procedure by which the valve cusp hypoxia (VCH) hypothesis of the etiology of deep venous thrombosis (DVT) was confirmed lends itself to testing of methods of prophylaxis. Similar animal experiments could end the present exclusive reliance on statistical analysis of data from large patient cohorts to evaluate prophylactic regimes. The reduction of need for such (usually retrospective) analyses could enable rationally-based clinical trials of prophylactic methods to be conducted more rapidly, and the success of such trials would lead to decreased incidences of DVT-related mortality and morbidity. This paper reviews the VCH hypothesis ("VCH thesis", following its corroboration) and its implications for understanding DVT and its sequelae, and outlines the experimental protocol for testing prophylactic methods. The advantages and limitations of the protocol are briefly discussed.

HIV-Associated Venous Thromboembolism

HIV infection has been recognized as a prothrombotic condition and this association has now been proven by a large number of studies with a reported VTE frequency among HIV-infected patients ranging from 0.19% to 7,63 %/year. HIV infection is associated with a two to tenfold increased risk of venous thrombosis in comparison with a general population of the same age. Some risk factors demonstrated a strongest association with VTE such as, low CD4⁺ cell count especially in the presence of clinical AIDS, protein S deficiency, and protein C deficiency. Whereas other risk factors are still controversial like protease inhibitor therapy, presence of active opportunistic infections and presence of antiphospholipid antibodies, including anticardiolipin antibodies and lupus anticoagulant. Physicians caring for HIV positive patients should be able to recognize and treat not only the well-known opportunistic infections and malignancies associated with this chronic disease, but also be alert to the less well-known complications such as thromboses. Pulmonary embolism should be included in the differential diagnosis when patients with HIV/AIDS have unexplained dyspnea or hypoxemia. In younger individuals with VTE, especially men, without other identifiable risk factors for VTE, HIV should be considered. Because interactions between warfarin and antiretrovirals is possible, health care providers should also be alert to the potential of dangerously high or low INRs when they are giving anticoagulants to patients with HIV infection who are undergoing antiretroviral therapy.

A large and massive abdominal venous thrombosis associated with the presence of a big axillary mass, lupus-like syndrome and antiphospholipid antibodies

This case report concerns a 40-year-old patient with an unspecific abdominal pain, diarrhoea, a big axillary mass and a previous pulmonary infection. After biopsy of the axillary mass the diagnosis of lymphoma was excluded based on the presence of cells expressing polyclonal antibodies. Abdominal CT scans and angionuclear magnetic resonance showed an extensive intestinal venous thrombosis. The patient also presented positive results for C and S proteins, lupic anticoagulant factor and antiphospholipid antibodies (anticardiolipin antibodies - IgM and IgG). Treatment started with administration of recombinant tissue plasminogen activator and heparin which decreased the degree of thrombosis. Antibiotics were also administrated to treat pulmonary and abdominal infections. After 25 days, he was discharged with no signs of infection, no abdominal pain and reduction of the thrombosis. He was medicated with warfarin, hydroxichloroquine and clopidogrel. Forty-five days after discharge, abdominal CT scan showed a significant regression of thrombosis.