Principle mechanisms underlying venous thromboembolism: epidemiology, risk factors, pathophysiology and pathogenesis

Hypertensive Disorders of Pregnancy and Pre-Pregnancy Hypertension with Subsequent Incident Venous Thromboembolic Events

Hypertensive disorders of pregnancy (HDP) and pre-pregnancy hypertension contribute to maternal morbidity and mortality. We examined the association of HDP and pre-pregnancy hypertension with subsequent venous thromboembolic (VTE) events. The retrospective cohort study included 444,859 women with ≥1 live, singleton birth in South Carolina (2004-2016). Hospital and emergency department visit and death certificate data defined incident VTE, HDP, and pre-pregnancy hypertension. Birth certificate data also defined the exposures. Adjusted Cox proportional hazards methods modeled VTE events risk. Of the cohort, 2.6% of women had pre-pregnancy hypertension, 5.8% had HDP, 2.8% had both pre-pregnancy hypertension and HDP (both conditions), and 88.8% had neither condition. The risk of incident VTE events within one year of delivery was higher in women with HDP (hazard ratio [HR] = 1.62, 95% confidence interval [CI]: 1.15-2.29) and both conditions (HR = 2.32, 95% CI: 1.60-3.35) compared to those with neither condition as was the risk within five years for women with HDP (HR = 1.35, 95% CI: 1.13-1.60) and for women with both conditions (HR = 1.82, 95% CI: 1.50-2.20). One- and five-year risks did not differ in women with pre-pregnancy hypertension compared to women with neither condition. Compared to non-Hispanic White (NHW) women with neither condition, the incident VTE event risk was elevated within five years of delivery for NHW (HR = 1.29, 95% CI: 1.02-1.63; HR = 1.59, 95% CI: 1.16-2.17) and non-Hispanic Black (NHB; HR = 1.51, 95% CI: 1.16-2.96; HR = 2.08, 95% CI: 1.62-2.66) women with HDP and with both conditions, respectively, and for NHB women with pre-pregnancy hypertension (HR = 1.50, 95% CI: 1.09-2.07). VTE event risk was highest in women with HDP, and the event rates were higher in NHB women than in NHW women in the same exposure group.

Impact of Prolonged Operative Duration on Postoperative Symptomatic Venous Thromboembolic Events After Thoracolumbar Spine Surgery

OBJECTIVE

To determine the effect of operative duration on the rate of postoperative symptomatic venous thromboembolic (VTE) events in patients undergoing thoracolumbar spine fusion.

METHODS

We identified all thoracolumbar spine fusion patients between 2012 and 2021. Operative duration was defined as time from skin incision to skin closure. A 1:1 propensity match was conducted incorporating patient and surgical characteristics. Logistic regression was performed to assess predictors of postoperative symptomatic VTE events. A receiver operating characteristic curve was created to determine a cutoff time for increased likelihood of VTE.

RESULTS

We identified 101 patients with VTE and 1108 patients without VTE. Seventy-five patients with VTE were matched to 75 patients without VTE. Operative duration (339 vs. 262 minutes, P = 0.010) and length of stay (5.00 vs. 3.54 days, P = 0.008) were significantly longer in patients with a VTE event. Operative duration was an independent predictor of VTE on multivariate regression (odds ratio: 1.003, 95% confidence interval: 1.001-1.01, P = 0.021). For each additional hour of operative duration, the risk of VTE increased by 18%. A cutoff time of 218 minutes was identified (area under the curve [95% confidence interval] = 0.622 [0.533-0.712]) as an optimal predictor of increased risk for a VTE event.

CONCLUSIONS

Operative duration significantly predicted symptomatic VTE, especially after surgical time cutoff of 218 minutes. Each additional hour of operative duration was found to increase VTE risk by 18%. We also identify the impact of VTE on 90-day readmission rates, suggesting significantly higher costs and opportunity for hospital acquired conditions, in line with prior literature.

Preperitoneal Pelvic Packing for Hypotension Has a Greater Risk of Venous Thromboembolism Than Angioembolization: Management of Refractory Hypotension in Closed Pelvic Ring Injury

BACKGROUND

Patients with traumatic pelvic ring injury may present with hypotension secondary to hemorrhage. Preperitoneal pelvic packing (PPP) and angioembolization (AE) are alternative interventions for management of hypotension associated with pelvic ring injury refractory to resuscitation and circumferential compression. We hypothesized that PPP may be independently associated with increased risk of venous thromboembolism (VTE) compared with AE in patients with hypotension and pelvic ring injury.

METHODS

Adult patients with pelvic ring injury and hypotension managed with PPP or AE were retrospectively identified in the Trauma Quality Improvement Program (TQIP) database from 2015 to 2019. Patients were matched on a propensity score for receiving PPP based on patient, injury, and treatment factors. The primary outcome was the risk of VTE after matching on the propensity score for treatment. The secondary outcomes included inpatient clinically important deep vein thrombosis, pulmonary embolism, respiratory failure, mortality, unplanned reoperation, sepsis, surgical site infection, hospital length of stay, and intensive care unit (ICU) length of stay.

RESULTS

In this study, 502 patients treated with PPP and 2,439 patients treated with AE met inclusion criteria. After propensity score matching on age, smoking status, Injury Severity Score, Tile B or C pelvic ring injury, bilateral femoral fracture, serious head injury, units of plasma and platelets given within 4 hours of admission, laparotomy, and level-I trauma center facility designation, 183 patients treated with PPP and 183 patients treated with AE remained. PPP, compared with AE, was associated with a 9.8% greater absolute risk of VTE, 6.5% greater risk of clinically important deep vein thrombosis, and 4.9% greater risk of respiratory failure after propensity score matching.

CONCLUSIONS

PPP for the management of hypotension associated with pelvic ring injury is associated with higher rates of inpatient VTE events and sequelae compared with AE.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Putative Biomarkers for Acute Pulmonary Embolism in Exhaled Breath Condensate

Current diagnostic markers for pulmonary embolism (PE) are unspecific. We investigated the proteome of the exhaled breath condensate (EBC) in a porcine model of acute PE in order to identify putative diagnostic markers for PE. EBC was collected at baseline and after the induction of autologous intermediate-risk PE in 14 pigs, plus four negative control pigs. The protein profiles of the EBC were analyzed using label-free quantitative nano liquid chromatography-tandem mass spectrometry. A total of 897 proteins were identified in the EBCs from the pigs. Alterations were found in the levels of 145 different proteins after PE compared with the baseline and negative controls: albumin was among the most upregulated proteins, with 14-fold higher levels 2.5 h after PE (p-value: 0.02). The levels of 49 other proteins were between 1.3- and 17.1-fold higher after PE. The levels of 95 proteins were lower after PE. Neutrophil gelatinase-associated lipocalin (fold change 0.3, p-value < 0.01) was among the most reduced proteins 2.5 h after PE. A prediction model based on penalized regression identified five proteins including albumin and neutrophil gelatinase-associated lipocalin. The model was capable of discriminating baseline samples from EBC samples collected 2.5 h after PE correctly in 22 out of 27 samples. In conclusion, the EBC from pigs with acute PE contained several putative diagnostic markers of PE.

Upadacitinib in Rheumatoid Arthritis: A Benefit-Risk Assessment Across a Phase III Program

Treating to a target of clinical remission or low disease activity is an important principle for managing rheumatoid arthritis (RA). Despite the availability of biologic disease-modifying antirheumatic drugs (bDMARDs), a substantial proportion of patients with RA do not achieve these treatment targets. Upadacitinib is a once-daily, oral Janus kinase (JAK) inhibitor with increased selectivity for JAK1 over JAK2, JAK3, and tyrosine kinase 2. The SELECT phase III upadacitinib clinical program comprised five pivotal trials of approximately 4400 patients with RA, including inadequate responders (IR) to conventional synthetic (cs)DMARDs or bDMARDs. This review aims to provide insights into the benefit-risk profile of upadacitinib in patients with RA. Upadacitinib 15 mg once daily, in combination with csDMARDs or as monotherapy, achieved all primary and ranked secondary endpoints in the five pivotal trials across csDMARD-naïve, csDMARD-IR, and bDMARD-IR populations. Upadacitinib 15 mg also demonstrated significantly higher rates of remission and low disease activity in all five pivotal trials, compared with placebo, methotrexate, or adalimumab. Labeled warnings of JAK inhibitors include serious infections, herpes zoster, malignancies, major cardiovascular events, and venous thromboembolic events. Short- and long-term integrated analyses showed that upadacitinib 15 mg was associated with increased risk of herpes zoster and creatine phosphokinase elevations compared with methotrexate and adalimumab but otherwise had comparable safety with these active comparators. This review suggests that upadacitinib 15 mg had a favorable benefit-risk profile. The safety of upadacitinib will continue to be monitored in long-term extensions and post-marketing studies.

Bariatric Surgery Outcomes in Patients on Preoperative Therapeutic Anticoagulation: an Analysis of the 2015 to 2017 MBSAQIP

BACKGROUND

Obesity has been found to be an independent predictor of adverse cardiac and pulmonary embolic events. As the popularity of bariatric surgery grows, surgeons are encountering more patients taking therapeutic anticoagulation medications preoperatively. This study aims to assess the safety of bariatric surgery on these patients.

METHODS

Data was extracted from 2015 to 2017 using the MBSAQIP database. Included patients were those who underwent a primary LSG or LRYGB. A multivariable regression analysis was performed looking at 30-day outcomes for pre-operatively anticoagulated patients. A secondary propensity-matched analysis was performed comparing outcomes among patients undergoing LSG vs LRYGB.

RESULTS

A total of 430,396 patients were analyzed, 11,013 (2.56%) of which were taking anticoagulation medications pre-operatively. Absolute 30-day complication rates (8.73% vs 3.36%, p < 0.001), bleed rates (3.78% vs 0.88%, p < 0.001), leak rates (0.55% vs 0.41%, p = 0.021), cardiac event rates (0.43% vs 0.06%, p < 0.001), and venous thromboembolism rates (0.68% vs 0.25%, p < 0.001) were significantly higher among pre-operatively anticoagulated patients. On multivariable analysis, pre-operative anticoagulation was found to be an independent predictor of postoperative bleeding (OR 2.76, CI 2.43-3.14, p < 0.001) and mortality (OR 2.08, CI 1.49-2.90, p < 0.001). The LRYGB was associated with a significantly higher complication rate compared to the LSG (13.27% vs 7.40%, p < 0.001) in the propensity-matched cohorts.

CONCLUSIONS

Patients undergoing bariatric surgery on anticoagulation medications pre-operatively are at a significantly higher risk of adverse outcomes post-operatively. Patients who require long-term anticoagulation should undergo careful consideration before proceeding with bariatric surgery.

Perioperative symptomatic venous thromboembolism after immediate chemoprophylaxis in patients with pelvic and lower-extremity fractures

The purpose of this study was to investigate the incidence of symptomatic venous thromboembolism (VTE) after chemoprophylaxis in patients with pelvic and lower-extremity fractures, and to identify risk factors for VTEs in this subgroup of patients. To detect VTE, multi-detector computed tomography (CT) angiography was performed. Of 363 patients assessed, the incidence of symptomatic VTE was 12.4% (45 patients), and the incidence of symptomatic PE was 5.2% (19 patients). For the risk-factor analysis, a higher Charlson comorbidity index (p = 0.037), and a history of external fixator application (p = 0.007) were associated with increased VTE risk. Among patients who had VTE, male sex (p = 0.017), and above-the-knee fractures (p = 0.035) were associated with increased pulmonary embolism (PE) risk. In conclusions, the incidence of VTE in post-traumatic patients is not low after chemoprophylaxis. Risk factors for VTE and PE are different among patients with pelvic and lower-extremity fractures.

Relationship between the site of thrombosis and the prevalence of pulmonary embolism in acute lower extremity deep venous thrombosis

OBJECTIVE

Lower extremity deep venous thrombosis (LEDVT) is common and can lead to pulmonary embolism (PE). Currently, the mechanism of how LEDVT causes PE is unclear. The aim of this study was to explore the relationship between the thrombus sites and PE in LEDVT patients.

METHODS

A retrospective study that included the medical data of 3101 patients aged >18 years who were diagnosed with LEDVT by duplex ultrasound was performed at The First Affiliated Hospital of Wenzhou Medical University from 2008 to 2017. The clinical information of the patients was collected. According to the thrombosis sites, the patients were divided into three groups. We determined the cumulative prevalence and prevalence rate of PE between the groups and used Cox proportional hazard regression models, which were stratified on matched sets, to calculate the hazard ratios (HRs) for all of the outcomes of interest. We focused on the relationship of proximal or isolated distal LEDVT with PE and also analyzed the relationship of the left side or right side of LEDVT with PE.

RESULTS

A total of 1629 (52.5%) patients had left LEDVT (group 1), 912 (29.4%) patients had right LEDVT (group 2), and 560 (18.1%) patients had bilateral LEDVT (group 3). The rate of PE was higher in group 2 than in group 1, although there were more patients suffering from LEDVT in group 1 than in group 2 (P < .001). The patients with proximal LEDVT in group 3 exhibited a greater risk of PE compared with those with isolated distal LEDVT (adjusted HR, 2.79; 95% confidence interval, 1.42-5.49). We also observed that the proportion of patients with proximal LEDVT who were receiving treatment was much higher than that of patients with distal LEDVT (P < .05). The patients with right LEDVT had a higher risk of PE than the patients with left LEDVT (adjusted HR, 1.60; 95% confidence interval, 1.15-2.21), and the patients with right LEDVT had more comorbidities, such as malignant neoplasms, hypertension, and diabetes (P < .001).

CONCLUSIONS

Patients with proximal bilateral LEDVT had a higher likelihood for development of PE than did patients with distal LEDVT, which may be associated with inadequate therapy for proximal bilateral LEDVT. PE was more likely to develop with right-sided LEDVT because these patients had more comorbidities in our study.

Prevalence and Characteristics of Venous Thrombosis after Catheter Ablation of Atrial Fibrillation in Patients Receiving Periprocedural Direct Oral Anticoagulants

Background

Periprocedural venous thromboembolisms (VTEs) area rare occurrence but a critical complication after catheter ablation of atrial fibrillation (AF).The aim of this study was to investigate the incidence of symptomatic deep vein thromboses (DVTs) and pulmonary thromboembolisms (PTEs) in patients who underwent AF catheter ablation and received periprocedural oral anticoagulation with direct oral anticoagulants (DOACs).

Methods and Results

A total of 2,193 consecutive patients undergoing AF catheter ablation with periprocedural DOACs were retrospectively analyzed.Two patients (0.091%) experienced symptomatic DVTs after the ablation, and no patients had any PTEs. One patient was a 72-year-old female who underwent cryoballoon ablation with periprocedural apixaban at a dose of 2.5 mg twice daily. The other patient was a 74-year-old male who underwent a Hot Balloon ablation and thereafter radiofrequency catheter ablation for recurrent AF with edoxaban at30 mg once daily. Both DVT patients underwent AF ablation by the right femoral vein approach, and after discharge had right leg pain and swelling on post-procedural days 4 and 8, respectively. TheDVT was treated by increasing the dose of apixaban and changing it from 30 mg/day of edoxaban to 15-30 mg/day of rivaroxaban, and the thrombi completely disappeared in both patients without any thromboembolic and hemorrhagic complications.

Conclusions

AF catheter ablation with periprocedural DOAC treatment revealed anextremely low incidence of symptomatic VTEs, which may be successfully treated by increasing the DOAC dose or changing the DOAC type.

Venous thromboembolism in the critically ill: A prospective observational study of occurrence, risk factors and outcome

BACKGROUND

The aim of the study was to explore occurrence, risk factors and outcome of venous thromboembolism (VTE) in intensive care unit (ICU) patients.

METHODS

Prospective observational study of ICU patients receiving thromboprophylaxis at Oslo University Hospital in Norway. Adult medical and surgical patients with ICU length of stay (LOS) longer than 48 hours were included. For detection of VTE, Doppler ultrasound screening of neck, upper and lower extremity veins was used, and computed tomography angiography when clinically indicated for any medical reason.

RESULTS

Among 70 included patients, 79% were males and mean age was 62 (±12.1) years. All received thromboprophylaxis with dalteparin, and 44 (63%) used graduated compression stockings. VTE was found in 19 (27%) patients; deep vein thrombosis in 15 (21%) and pulmonary embolism in 4 (6%). Among the VTEs, 11 (58%) presented within the first 48 hours after admission, two (11%) were located in the lower limbs and five (26%) were symptomatic. Risk factors for VTE in multivariable analyses were malignancy, abdominal surgery and SAPS II score <41 with an AuROC (95% CI) of 0.72 (0.58-0.85, P = 0.01). Patients with and without VTE had comparable ICU LOS (13 vs 11 days, P = 0.27) and mortality (16% vs 20%, P = 0.72).

CONCLUSION

Venous thromboembolism was observed in 27% of ICU patients receiving thromboprophylaxis. Factors associated with increased risk of VTE were malignancy, abdominal surgery and SAPS II score <41. Presence of VTE did not impact on patient outcome.

Predicting venous thromboembolism following laparoscopic bariatric surgery: development of the BariClot tool using the MBSAQIP database

BACKGROUND

Bariatric surgery is an effective treatment for severe obesity; however, postoperative venous thromboembolism (VTE) remains a leading cause of morbidity and mortality. The objective of this study is to develop a tool to stratify individuals undergoing laparoscopic bariatric surgery according to their 30-day VTE risk.

METHODS

This is a retrospective cohort study of the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) database. This registry collects data specific for metabolic or bariatric surgery with 30-day outcomes from 791 centers. Individuals undergoing primary laparoscopic Roux-en-Y gastric bypass (LRYGB) or laparoscopic sleeve gastrectomy (LSG) were included. Characteristics associated with 30-day VTE were identified using univariate and multivariable analyses. A predictive model, BariClot, was derived from a randomly-generated derivation cohort using a forward selection algorithm. BariClot's robustness was tested against a validation cohort of subjects not included in the derivation cohort. The calibration and discrimination of two previously published VTE risk tools were assessed in the MBSAQIP population and compared to BariClot.

RESULTS

A total of 274,221 patients underwent LRYGB or LSG. Overall, 1106 (0.4%) patients developed VTE, 452 (0.2%) developed pulmonary embolism, and 43 (0.02%) died due to VTE. VTE was the most commonly identified cause of 30-day mortality. A prediction model to assess for risk of VTE, BariClot, was derived and validated. BariClot consists of history of VTE, operative time, race, and functional status. It stratifies individuals into very high (> 2%), high (1-2%), medium (0.3-1%), and low risk groups (< 0.3%). This model accurately predicted events in the validation cohort and outperformed previously published scoring systems.

CONCLUSIONS

BariClot is a predictive tool that stratifies individuals undergoing bariatric surgery based on 30-day VTE risk. Stratifying low- and high-risk populations for VTE allows for informed clinical decision-making and potentially enables further research on customized prophylactic measures for low- and high-risk populations.

Fibrin polymerization simulation using a reactive dissipative particle dynamics method

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

Recent progress and market analysis of anticoagulant drugs

This review describes epidemiology of thromboembolic disease in China and abroad, evaluates trends in the development of anticoagulant drugs, and analyzes the market situation based on large amounts of accumulated data. Specifically, we describe advances in clinical application of anticoagulants and analyze the most commonly used anticoagulants in the market systematically.

The Role of Inflammation in Venous Thromboembolism

Venous thromboembolism (VTE), comprising deep vein thrombosis (DVT), and pulmonary embolism (PE), is becoming increasingly recognized as a cause of morbidity and mortality in pediatrics, particularly among hospitalized children. Furthermore, evidence is accumulating that suggests the inflammatory response may be a cause, as well as consequence, of VTE, but current anticoagulation treatment regimens are not designed to inhibit inflammation. In fact, many established clinical VTE risk factors such as surgery, obesity, cystic fibrosis, sepsis, systemic infection, cancer, inflammatory bowel disease, and lupus likely modulate thrombosis through inflammatory mediators. Unlike other traumatic mechanisms of thrombosis involving vascular transection and subsequent exposure of subendothelial collagen and other procoagulant extracellular matrix materials, inflammation of the vessel wall may initiate thrombosis on an intact vein. Activation of endothelial cells, platelets, and leukocytes with subsequent formation of microparticles can trigger the coagulation system through the induction of tissue factor (TF). Identification of biomarkers to evaluate VTE risk could be of great use to the clinician caring for a patient with inflammatory disease to guide decisions regarding the risk:benefit ratio of various types of potential thromboprophylaxis strategies, or suggest a role for anti-inflammatory therapy. Unfortunately, no such validated inflammatory scoring system yet exists, though research in this area is ongoing. Elevation of C-reactive protein, IL-6, IL-8, and TNF-alpha during a response to systemic inflammation have been associated with increased VTE risk. Consequent platelet activation enhances the prothrombotic state, leading to VTE development, particularly in patients with other risk factors, most notably central venous catheters.

Venous and arterial thrombosis – pathogenesis and the rationale for anticoagulation

Thromboembolic disorders are major causes of morbidity and mortality. It is well-recognised that the pathogenesis is different for arterial and venous thrombosis; however, both involve coagulation activation. Anticoagulants are used for the prevention and treatment of a wide variety of thromboembolic and related conditions. Agents with anti-inflammatory properties in addition to anticoagulation may be particularly beneficial. Traditional anticoagulants, although effective, are associated with certain limitations. Understanding the pathological processes associated with thrombosis and the rational target for anticoagulation is essential, not only for the development of safer and more effective agents, but also for better clinical management of patients who require anticoagulation therapy. In recent years, new oral agents that target single enzymes of the coagulation cascade have been developed – some of those are in advanced stages of clinical development. Based on scientific rationale, both factor Xa and thrombin are viable targets for effective anticoagulation.

Medico-Legal Aspects of Pulmonary Thromboembolism

Pulmonary ThromboEmolism (PTE) is an important disease for legal medicine. Because of their sudden lethal onset, generally medicolegal autopsies show few clinical information when PTE is the cause of death. During medicolegal autopsies, the autopsy operator must answer to important questions. For example, autopsy operator can need to assess the casual relationship between PTE and recent accident, such as trauma or long air travel. Furthermore, the autopsy operator needs to investigate the pathology of PTE as a cause of sudden cardiovascular death. It is relatively simple to confirm a fatal massive thromboembolus in the initial stage of thoracic investigations, but sometimes it might be difficult to distinguish this from postmortem clot. In such cases histopathological examination can help in the differentiation. Histological examination is also required for observation of chronological changes of the thrombi. Chronological evaluation is an important factor especially to determine whether the death coincides with the date of a specific accident/event or instead there is an earlier onset of PTE. In addition, histological sections sometimes show additional information, such as tumor fragments in cases of malignancy or small fragments of bone marrow in cases of active resuscitation, that can be useful in a medicolegal scenario. Furthermore, new diagnostic tools are arising, which they can be very helpful in the individuation of this frequently underdiagnosed disease. The goal of our work is to investigate these aspects through the review of the recent literature.

Pulmonary Infarction: In the Beginning: The Natural History of Pulmonary Infarction

BACKGROUND

Massive pulmonary emboli can cause an abrupt onset of symptoms simultaneous with large pulmonary artery occlusions. In contrast, the temporal relationship between pulmonary vascular occlusion by smaller emboli and the development of symptoms of pulmonary infarction is unknown. We describe the time interval between embolization and the onset of clinical symptoms and signs compatible with pulmonary infarction.

METHODS

We examined the records of 56 patients with hereditary hemorrhagic telangiectasia (HHT) who underwent therapeutic balloon embolization of pulmonary arteriovenous malformation (PAVM) in a single center after noting that some of them experienced symptoms and signs compatible with pulmonary infarction. Because both the times of embolization and the onset of clinical symptoms were documented in medical records, we were able to calculate the time interval between embolic occlusion of vessels and the onset of symptoms.

RESULTS

The records of 56 patients who underwent therapeutic embolization for HHT were examined. Five patients experienced a single episode of pleuritic pain postembolization, and one patient experienced episodes of pleuritic pain after each of two separate embolization procedures. Four of these pleuritic pain events evolved into a complex compatible with pulmonary infarction. The time intervals between embolization and the onset of pleuritic pain in those experiencing the infarction symptoms and signs were 24 hours, 48 ± 4 hours, 65 hours, and 67 hours, respectively.

CONCLUSIONS

The clinically silent time interval between embolization of a pulmonary artery and the onset of symptoms and signs compatible with lung infarction is 24 hours or greater.

Increased risk of deep vein thrombosis and pulmonary thromboembolism in patients with aortic aneurysms: A nationwide cohort study

Studies on the association between aortic aneurysm (AA) and the subsequent risk of venous thromboembolism (VTE) are limited to a few case reports and investigations which only focused on surgical effects. Therefore, we used the National Health Insurance Research Database to clarify whether patients with AAs have a heightened risk of subsequent VTEs, including deep vein thrombosis (DVT) and pulmonary embolism (PE). Our retrospective cohort study comprised patients aged ≥ 18 years who received a diagnosis of an AA and were hospitalized at any point during 2000–2010 (n = 16,630). Each AA patient was frequency-matched to 4 non-AA hospitalized patients based on age, sex, and index year (n = 66,453). The Cox proportional hazard regressions model was used to estimate the adjusted effect of AAs on VTE risk. The overall incidence of DVT and PE was higher in the patients with AA than in the non-AA group patients (23.5 versus 13.2 and 13.5 versus 7.98/1,000 person-years). After adjustment for age, sex, duration of hospitalization in the study period, and comorbidities, patients with AAs were associated with a 1.88-fold higher risk of DVT and 1.90-fold higher risk of PE compared to the non-AA cohort. Patients with abdominal AAs were more likely to develop DVT, whereas thoracic AA patients were more likely to develop PE. A diagnosis of a ruptured AA was associated with a substantially increased risk of DVT. Surgical treatment of AAs was associated with a heightened risk of VTE within 6-months post-operation. Our study demonstrates that AAs are associated with an increased risk of subsequent VTE. Future investigations are encouraged to delineate the mechanisms underlying this association and to evaluate the cost-effectiveness of screening for VTEs in patients with AAs.

Prophylaxis of Venous Thromboembolism in Home Care: An Integrative Review

Venous thromboembolism (VTE) is a set of diseases that carries both the risk of sudden death and long-term morbidity. Several studies conducted in Brazilian hospitals have identified that most patients considered at high risk for VTE do not receive prophylactic anticoagulant prescription properly. Risk of VTE in patients under home care is unknown. The objective of this integrative review is to identify evidence regarding prophylaxis of VTE in home care. The databases PubMed/Medline, LILACS, and National Guideline Clearinghouse were searched for articles published between January 1985 and June 2015. Although there is an extensive literature and clear guidelines for the prophylaxis and treatment of VTE in the hospital environment, studies on the same subject in home care are scarce, sometimes small, and almost exclusively based on retrospective collection of chart data. Additional research on VTE prophylaxis in the home care setting is needed in order to develop evidence-based practice guidelines.

The efficacy of bedside chest ultrasound: from accuracy to outcomes

For many respiratory physicians, point-of-care chest ultrasound is now an integral part of clinical practice. The diagnostic accuracy of ultrasound to detect abnormalities of the pleura, the lung parenchyma and the thoracic musculoskeletal system is well described. However, the efficacy of a test extends beyond just diagnostic accuracy. The true value of a test depends on the degree to which diagnostic accuracy efficacy influences decision-making efficacy, and the subsequent extent to which this impacts health outcome efficacy. We therefore reviewed the demonstrable levels of test efficacy for bedside ultrasound of the pleura, lung parenchyma and thoracic musculoskeletal system.For bedside ultrasound of the pleura, there is evidence supporting diagnostic accuracy efficacy, decision-making efficacy and health outcome efficacy, predominantly in guiding pleural interventions. For the lung parenchyma, chest ultrasound has an impact on diagnostic accuracy and decision-making for patients presenting with acute respiratory failure or breathlessness, but there are no data as yet on actual health outcomes. For ultrasound of the thoracic musculoskeletal system, there is robust evidence only for diagnostic accuracy efficacy.We therefore outline avenues to further validate bedside chest ultrasound beyond diagnostic accuracy, with an emphasis on confirming enhanced health outcomes.

Acute Pain Management

Acute pain management is improving steadily over the past few years, but training and professional education are still lacking in many professions. Untreated or undertreated acute pain could have detrimental effects on the patient in terms of comfort and recovery from trauma or surgery. Acute undertreated pain can decrease a patient's vascular perfusion, increase oxygen demand, suppress the immune system, and possibly risk increased incidence of venous thrombosis. Although acute postoperative pain needs to be managed aggressively, patients are most vulnerable during this period for developing adverse effects, and therefore, patient assessment and careful drug therapy evaluation are necessary processes in therapeutic planning. Acute pain management requires careful and thorough initial assessment and follow-up reassessment in addition to frequent dosage adjustments, and managing analgesic induced side effects. Analgesic selection and dosing must be based on the patient's past and recent analgesic exposure. There is no single acute pain management regimen that is suitable for all patients. Analgesics must be tailored to the individual patient.

Ramifications of Four Concurrent Thrombophilic Mutations and One Hypofibrinolytic Mutation

A kindred was examined in which the 48-year-old white female proband with three deep venous thrombosis-pulmonary emboli events had four thrombophilic and one hypofibrinolytic mutations, and in which her 14-year-old asymptomatic daughter had four thrombophilic mutations. The proband was heterozygous for the G1691A factor V Leiden, G20210A prothrombin, and platelet glycoprotein IIIa PL A1/A2 mutations, had high factor VIII (221%), and was homozygous for the 4G4G plasminogen activator inhibitor-1 gene mutation, with high plasminogen activator inhibitor activity (23.7 U/mL). Her 14-year-old daughter was homozygous for the G1691A factor V Leiden and platelet glycoprotein IIb-IIIa PL A2/A2 mutations, compound heterozygous for the C677T and A1298C methylenetetrahydrofolate reductase (MTHFR) mutations, and heterozygous for the G20210A prothrombin mutation, a combination with an estimated likelihood of 1.6 × 10-7. In 247 white healthy controls, there was no V Leiden homozygosity and no V Leiden-prothrombin gene compound heterozygosity. Heterozygosity for the V Leiden and prothrombin gene mutations was 3.2% and 4.1%, respectively. Homozygosity for the platelet glycoprotein IIb-IIIa PL A2A2, PAI-1 gene 4G4G, and C677T MTHFR mutations was 3.2%, 22.7%, and 12%, respectively. The proband will receive anticoagulation therapy for life. Beyond aspirin, avoidance of exogenous estrogens, and enoxaparin prophylaxis during pregnancy, it is not known whether the proband’s daughter should have lifelong anticoagulation therapy, or only after her first thrombotic event.

Pulmonary embolism as a complication of an electrophysiological study: a case report

BACKGROUND

Electrophysiological studies have become an established practice in the evaluation and treatment of arrhythmias. Symptomatic pulmonary embolism as a result of deep vein thrombosis arising from multiple venous sheath femoral vein catheterization is an uncommon complication associated with it. We report the case of a 33-year-old woman who developed pulmonary embolism after an electrophysiological study, which was successfully treated at a cardiac hospital in Bangladesh.

CASE PRESENTATION

A 33-year-old Bangladeshi woman with hypertension and diabetes had initially presented with recurrent episodes of paroxysmal atrial fibrillation that manifested as palpitations for 2 years. Her atrial fibrillation was drug-refractory and could not be attributed to a treatable etiology. She had undergone an electrophysiological study at a different hospital, where right femoral venous catheterization was performed followed by the insertion of three venous sheaths. However, tachyarrhythmia could not be induced and a procedure to isolate the pulmonary vein was postponed because all the veins could not be isolated. Forty-eight hours later, she presented to our hospital with shortness of breath, chest heaviness, palpitations, and recurrent episodes of syncope. She had normal coronary arteries and no other risk factors for venous thromboembolism. She was hemodynamically stable on examination. There was echocardiographic evidence of pulmonary hypertension and right ventricular dilatation and dysfunction. A computed tomography pulmonary angiogram confirmed pulmonary embolus in the descending branch of her left pulmonary artery, extending up to the segmental arteries. Subsequently, a duplex ultrasound confirmed acute deep vein thrombosis affecting her right ilio-femoral segment. She was successfully managed with subcutaneous enoxaparin and oral warfarin (target international normalized ratio 2.5-3).

CONCLUSIONS

Pulmonary embolism is a rare but serious complication that may occur in patients who undergo electrophysiological studies. Multiple venous sheaths inserted into the femoral vein and catheter-induced endothelial injury, further compounded by prolonged procedural time, may be responsible for the increased thrombogenicity leading to deep vein thrombosis and subsequent pulmonary embolism. An adequate observation time after the procedure and clinical alertness are necessary for rapid diagnosis and treatment.

Venous thromboembolism: identifying patients at risk and establishing prophylaxis

Venous thromboembolism (VTE) is a major cause of morbidity and mortality and is associated with substantial healthcare costs. Identification of patients at risk of developing VTE enables appropriate thromboprophylaxis to be implemented. Although no predisposing risk factors can be identified in many patients in whom VTE develops, most have at least one underlying risk factor which can be categorized according to whether it confers low, moderate, or high risk. Clinical trials have demonstrated the effectiveness of thromboprophylaxis, both non-pharmacological and pharmacological, in a host of medical settings and there is sufficient evidence to support routine prophylaxis in many groups of patients. The implementation of decision making tools based on risk factor assessment improves the prescription of appropriate VTE prophylaxis. Nonetheless, thromboprophylaxis is often inadequate, with haphazard risk assessment and application of guidelines, leading to easily preventable instances of VTE. The most commonly used agents for pharmacological thromboprophylaxis of VTE are low dose unfractionated heparin; a low molecular weight heparin such as dalteparin, enoxaparin or tinzaparin; fondaparinux; warfarin; or aspirin. However, these have a number of drawbacks, principally the need for parenteral administration (with heparins) and frequent coagulation monitoring (with warfarin). The optimal anticoagulant would be orally administered, with a wide therapeutic window, rapid onset of action, predictable pharmacodynamics and pharmacokinetics, minimal interactions with food and other drugs, an ability to inhibit free and clot-bound coagulation factors, low, non-specific binding, and no requirement for routine coagulation monitoring or dose adjustment. A number of novel, single-target oral anticoagulants have been developed that appear to fulfill many of these requirements. This narrative review discusses the use of guidelines and risk assessment tools to identify patients at risk of VTE; it provides an overview of appropriate prophylaxis strategies in these patients with a summary of clinical trial results with novel oral anticoagulants.

Inflammation in venous thromboembolism: Cause or consequence?

Venous thromboembolism (VTE) which includes deep vein thrombosis (DVT) and pulmonary thromboembolism (PTE) is a moderately common disease especially in elderly population with high rate of recurrence and complications. Evidence is accumulating that VTE is not restricted to coagulation system and immune system appears to be involved in formation and resolution of thrombus. The present study was aimed at reviewing current evidences on immune system abnormalities such as alterations in cytokines, chemokines and immune cells. Also, current evidences suggest that; a, inflammation in general functions as a double-edged sword, b, inflammation can be both a cause and a consequence of VTE, and c, current anti-coagulation therapies are not well-equipped with the capacity to selectively inhibit inflammatory cells and pathways. Applying such inferences for selective pharmacological targeting of immune mediators in VTE and thereby for adoption of higher effective anti-thromboinflammatory strategies, either therapeutic or prophylactic, is henceforth to be considered as the line of research for future.

Interdisciplinary management of deep vein thrombosis during rehabilitation of acute rupture of the anterior cruciate ligament: a case report

OBJECTIVE

The purpose of this case report is to describe a patient who experienced deep venous thrombosis (DVT) during pre-operative rehabilitation of an acute rupture of an anterior cruciate ligament (ACL) reconstruction graft, to increase awareness of DVT occurring in a healthy individual after periodic immobilization, and to describe the interdisciplinary management for this patient.

CLINICAL FEATURES

A 30-year-old male was referred to a chiropractic clinic for presurgical treatment of a left ACL rupture and medial meniscus tear confirmed at magnetic resonance imaging. During the course of preoperative rehabilitation, the patient became limited in ambulation and presented for a routine rehabilitation visit. During this visit, he experienced increased leg swelling, pain and tenderness. The patient was assessed for DVT and was referred to the local emergency department for further evaluation where multiple DVTs were found in the left popliteal, posterior tibial, and peroneal veins.

INTERVENTION/OUTCOME

The patient was treated with a 17-week course of warfarin during which time the clinical signs and symptoms of DVT resolved. Meanwhile, the patient completed the rehabilitation treatment plan in preparation for ACL reconstruction without further complications.

CONCLUSIONS

This case raises awareness that DVT may occur in a healthy individual after periodic immobilization. While there may be controversy regarding the appropriate application of pharmaceutical anticoagulants in patients with DVT of the leg, the most risk averse strategy is for a short duration prescription medication with compression stockings. Through interdisciplinary management, the patient experienced a successful outcome.

Sudden Death by Pulmonary Thromboembolism due to a Large Uterine Leiomyoma with a Parasitic Vein to the Mesentery

The pathophysiology of venous thrombosis is classically attributed to alterations in one or more components of Virchow's triad: hypercoagulability, stasis, and damage to the vascular endothelium. Deep vein thrombosis (DVT) may lead to pulmonary thromboembolism (PE), and the latter is culpable for many deaths annually in the United States; however, DVT as a complication of uterine leiomyoma has rarely been reported. We report a case of a 57-year-old woman whose death was due to a large pedunculated subserosal leiomyoma externally compressing the pelvic veins resulting in stasis and venous thrombosis leading to fatal PE. The association of large pelvic masses with venous thrombosis has clinical implications, since prophylactic surgery could be life-saving.

Clear cell carcinoma of the ovary associated with increased risk of venous thrombosis

Clear cell carcinoma of the ovary (CCCO) is an uncommon, clinically aggressive neoplasm that has a propensity for the development of venous thrombosis and embolization, especially when compared to other subtypes of ovarian malignancies. We present a fatal case of a 59-year-old woman with a clinical course complicated by venous thrombosis and pulmonary thromboembolism that was attributed to CCCO discovered initially at autopsy.

The use of oral anticoagulants for the treatment of venous thromboembolic events in an ED

Venous thromboembolism (VTE) is a disease spectrum that ranges from deep vein thrombosis (DVT) to pulmonary embolism (PE). Rapid diagnosis and treatment of VTE by emergency care providers are critical for decreasing patient mortality, morbidity, and the incidence of recurrent events. Recent American College of Chest Physicians guidelines recommend initial treatment with unfractionated heparin, low-molecular weight heparin, or fondaparinux overlapped with warfarin for a minimum of 5 days for the treatment of VTE in most cases. Warfarin monotherapy is thereafter continued for 3, 6, or 12 months. These guidelines were published before the approval of target-specific oral anticoagulants (TSOACs), and they have yet to be updated to reflect these new treatment options. For some patients, TSOACs, which act by directly inhibiting factor IIa or factor Xa, may provide safer, more convenient alternatives to warfarin. Their advantages include ease of use, reduced monitoring requirements, and lower bleeding risk than traditional therapy. Additionally, clinical trials have established noninferiority of TSOACs to warfarin for the prevention of recurrent VTE. These trials have demonstrated that TSOACs exhibit similar or lower bleeding rates, particularly intracranial bleeding rates compared with warfarin. Anticoagulation therapy with TSOACs may allow early discharge or outpatient management options for low-risk patients with DVT and PE. This review addresses the importance of early diagnosis and treatment of VTE, outcomes of VTE risk assessment, key efficacy and safety data from phase 3 clinical trials for the various TSOACs for the treatment of DVT and PE, and the corresponding considerations for clinical practice.

Glycemia (hemoglobin A1c) and incident venous thromboembolism in the Atherosclerosis Risk in Communities cohort study

Diabetes has been inconsistently associated with increased risk of venous thromboembolism (VTE) and there is little direct evidence on the associations of glycemia levels with VTE. We used data from the Atherosclerosis Risk in Communities study to test the hypothesis that glycemia, as measured by hemoglobin A1c (A1c), is positively associated with VTE. Participants aged 45-64 years (n = 12,298) had A1c measured in 1990 and were followed for incident VTE (n = 345) through 2005. Because A1c is affected by diabetes treatment, analyses were stratified by history of diagnosed diabetes. Owing to evidence of non-linearity, we categorized A1c according to clinical cut-points: <5.7, 5.7-6.4, and ≥ 6.5% in those with no diagnosed diabetes; <7.0 and ≥ 7.0% in those with diagnosed diabetes. After adjustment for potential confounders, the hazard ratios (95% CIs) for VTE across increasing A1c categories were 1 (referent), 1.02 (0.77, 1.35) and 0.72 (0.41, 1.29) for those without diagnosed diabetes, and 1.30 (0.77, 2.17) and 1.41 (0.95, 2.09) for those with diagnosed diabetes. To explore the relation, we employed various models to adjust for potential confounding variables and modeled A1c as tertiles. We consistently found elevated hazard ratios in those with diagnosed diabetes, though the association was not statistically significant in every model. Hazard ratios in those without diagnosed diabetes were close to 1. In conclusion, our results are mildly suggestive that diagnosed diabetes and high levels of glucose, per se, may increase the risk of VTE. Elevated glucose was not related to VTE in those without diagnosed diabetes.

Elevated heparin-induced antibodies are more common in diabetic patients with vascular disease

Background. Hypercoagulable disorders can lead to deep vein thrombosis (DVT), arterial thrombosis or embolization, and early or recurrent bypass graft failure. The purpose of this study was to identify whether diabetes increased the likelihood of heparin-induced platelet factor 4 antibodies in at risk vascular patients. Methods. We reviewed clinical data on 300 consecutive patients. A hypercoagulable workup was performed if patients presented with (1) early bypass/graft thrombosis (<30 days), (2) multiple bypass/graft thrombosis, and (3) a history of DVT, pulmonary embolus (PE), or native vessel thrombosis. Relevant clinical variables were analyzed and compared between patients with diabetes (DM) and without diabetes (nDM). Results. 85 patients (47 women; age 53 ± 16 years, range 16–82 years) had one of the defined conditions and underwent a hypercoagulable evaluation. Screening was done in 4.7% of patients with early bypass graft thrombosis, 60% of patients were screened because of multiple bypass or graft thrombosis, and 35.3% had a previous history of DVT, PE, or native vessel thrombosis. Of the 43 patients with DM and 42 nDM evaluated, 59 patients (69%) had an abnormal hypercoagulable profile. An elevated heparin antibody level was present in 30% of DM and 12% of nDM patients (chi-squared test P < 0.04). Additionally, DM was associated with a higher likelihood of arterial complications while nDM was associated with a higher rate of venous adverse events (chi-squared test P < 0.003). Conclusions. Diabetes is associated with a higher likelihood of developing heparin-induced antibodies and an increased combined incidence of arterial complications that include early or multiple bypass/graft thrombosis. This finding may influence the choice of anticoagulation in diabetic patients at risk with vascular disease.

Impact on hemostatic parameters of interrupting sitting with intermittent activity

INTRODUCTION

Excessive sitting has been associated with an elevated risk of vascular conditions, particularly venous thrombosis. Interrupting sitting time with intermittent physical activity can reduce venous stasis; however, impacts on other aspects of thrombogenesis are less understood.

PURPOSE

To examine the effects of interrupting sitting time on blood coagulation and blood volume parameters in sedentary, middle-age, overweight/obese adults (11 men and 8 women; age = 53.8 ± 4.9 yr, body mass index = 31.2 ± 4.1 kg · m(-2); mean ± SD).

METHODS

The randomized three-period, three-treatment acute crossover trial consisted of uninterrupted sitting and sitting interrupted by 2-min bouts of either light- or moderate-intensity treadmill walking every 20 min. In each trial condition, blood samples were collected at baseline before the consumption of a standardized meal (-2 h) and postintervention (5 h).

RESULTS

Plasma fibrinogen increased from baseline with uninterrupted sitting (0.24 g · L(-2), 95% confidence interval = 0.13-0.34, P < 0.001). Light-intensity but not moderate-intensity activity breaks attenuated the increase by 0.17 g · L(-1) (95% confidence interval = 0.01-0.32, P < 0.05). There were no between-condition differences in prothrombin time, activated partial thromboplastin time, von Willebrand factor, D-dimer, or platelet count. Uninterrupted sitting reduced plasma volume and increased hematocrit, hemoglobin, and red blood cell count; effects attenuated by both light- and moderate-intensity breaks (P < 0.05). White blood cell count increased with uninterrupted sitting and further increased with moderate-intensity breaks. Mean platelet volume increased with moderate-intensity but not light-intensity breaks or uninterrupted sitting.

CONCLUSION

Uninterrupted sitting increased fibrinogen and reduced plasma volume, with associated increases in hemoglobin and hematocrit. Activity breaks attenuated these responses, indicative of an ameliorating influence on the procoagulant effects of uninterrupted sitting.

Pulmonary thromboembolism due to paliperidone: report of 2 cases

Venous thromboembolism (VTE) is serious medical condition, which might be caused by psychotropic medications. Previously, antipsychotic-induced VTE due to olanzapine, risperidone, clozapine, and amisulpiride was reported. In this report, we present 2 cases of paliperidone-induced VTE.

Can enoxaparin reduce thromboembolism related events after primary TKA in Asian patients?

The purpose of this study was to investigate the efficacy and safety of enoxaparin in preventing venous and arterial thromboembolism related events after primary total knee arthroplasty (TKA) in Asian patients. Four hundred twenty nine patients (621 TKAs) did not receive thromboprophylaxis after TKA and 907 patients (1,336 TKAs) received enoxaparin after the procedure. We assessed clinically significant venous and arterial thromboembolism related events and bleeding complications. Total thromboembolism related events occurred in 13 patients (3.03%) without thromboprophylaxis and 17 patients (1.87%) with enoxaparin (P = 0.183). Our study showed that the incidence of clinically significant thromboembolism related events after TKA was very low in Asian patients. Enoxaparin had no benefits in reducing thromboembolism related events in Asian patients.

Dual-energy CT based vascular iodine analysis improves sensitivity for peripheral pulmonary artery thrombus detection: an experimental study in canines

PURPOSE

To evaluate the performance of dual-energy CT (DECT) based vascular iodine analysis for the detection of acute peripheral pulmonary thrombus (PE) in a canine model with histopathological findings as the reference standard.

MATERIALS AND METHODS

The study protocol was approved by our institutional animal committee. Thrombi (n = 12) or saline (n = 4) were intravenously injected via right femoral vein in sixteen dogs, respectively. CT pulmonary angiography (CTPA) in DECT mode was performed and conventional CTPA images and DECT based vascular iodine studies using Lung Vessels application were reconstructed. Two radiologists visually evaluated the number and location of PEs using conventional CTPA and DECT series on a per-animal and a per-clot basis. Detailed histopathological examination of lung specimens and catheter angiography served as reference standard. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of DECT and CTPA were calculated on a segmental and subsegmental or more distal pulmonary artery basis. Weighted κ values were computed to evaluate inter-modality and inter-reader agreement.

RESULTS

Thirteen dogs were enrolled for final image analysis (experimental group = 9, control group = 4). Histopathological results revealed 237 emboli in 45 lung lobes in 9 experimental dogs, 11 emboli in segmental pulmonary arteries, 49 in subsegmental pulmonary arteries, 177 in fifth-order or more distal pulmonary arteries. Overall sensitivity, specificity, accuracy, PPV, and NPV for CTPA plus DECT were 93.1%, 76.9%, 87.8%, 89.4%, and 84.2% for the detection of pulmonary emboli. With CTPA versus DECT, sensitivities, specificities, accuracies, PPVs, and NPVs are all 100% for the detection of pulmonary emboli on a segmental pulmonary artery basis, 88.9%, 100%, 96.0%, 100%, and 94.1% for CTPA and 90.4%, 93.0%, 92.0%, 88.7%, and 94.1% for DECT on a subsegmental pulmonary artery basis; 23.8%, 96.4%, 50.4%, 93.5%, and 36.7% for CTPA and 95.9%, 75.5%, 88.2%, 86.5%, and 91.9% on a sub-subsegmental and more distal pulmonary artery basis, respectively. Good inter-modality (κ = 0.65, P<0.001) and inter-reader (κ = 0.70, P<0.001) agreement were observed.

CONCLUSION

With histopathological findings as the reference standard, DECT based vascular iodine analysis improves the sensitivity for detecting peripheral PE compared with CTPA, albeit at the price of decreased specificity and PPV.

Transitions of care in anticoagulated patients

Anticoagulation is an effective therapeutic means of reducing thrombotic risk in patients with various conditions, including atrial fibrillation, mechanical heart valves, and major surgery. By its nature, anticoagulation increases the risk of bleeding; this risk is particularly high during transitions of care. Established anticoagulants are not ideal, due to requirements for parenteral administration, narrow therapeutic indices, and/or a need for frequent therapeutic monitoring. The development of effective oral anticoagulants that are administered as a fixed dose, have low potential for drug-drug and drug-food interactions, do not require regular anticoagulation monitoring, and are suitable for both inpatient and outpatient use is to be welcomed. Three new oral anticoagulants, the direct thrombin inhibitor, dabigatran etexilate, and the factor Xa inhibitors, rivaroxaban and apixaban, have been approved in the US for reducing the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation; rivaroxaban is also approved for prophylaxis and treatment of deep vein thrombosis, which may lead to pulmonary embolism in patients undergoing knee or hip replacement surgery. This review examines current options for anticoagulant therapy, with a focus on maintaining efficacy and safety during transitions of care. The characteristics of dabigatran etexilate, rivaroxaban, and apixaban are discussed in the context of traditional anticoagulant therapy.