An elevated D-dimer value: a burden on our patients and hospitals

The James A. Rand Young Investigator's Award: Keeping It Simple: Are all Musculoskeletal Infection Society Tests Useful to Diagnose Periprosthetic Joint Infection?

BACKGROUND

Current data evaluating the clinical value and cost-effectiveness of advanced diagnostic tests for periprosthetic joint infection (PJI) diagnosis, including alpha-defensin and synovial C-reactive protein (CRP), is conflicting. This study aimed to evaluate the adequacy of preoperative and intraoperative PJI workups without utilizing these tests.

METHODS

This retrospective analysis identified all patients who underwent revision total knee or hip arthroplasty (rTKA and rTHA, respectively) for suspected PJI between 2018 and 2020 and had a minimum follow-up of 2 years. Perioperative data and lab results were collected, and cases were dichotomized based on whether they met the 2018 Musculoskeletal Infection Society (MSIS) criteria for PJI. In total, 204 rTKA and 158 rTHA cases suspected of PJI were reviewed.

RESULTS

Nearly 100% of the cases were categorized as "infected" for meeting the 2018 MSIS criteria without utilization of alpha-defensin or synovial CRP (rTKA: n = 193, 94.6%; rTHA: n = 156, 98.7%). Most cases were classified as PJI preoperatively by meeting either the major MSIS or the combinational minor MSIS criteria of traditional lab tests (rTKA: n = 177, 86.8%; rTHA: n = 143, 90.5%). A subset of cases was classified as PJI by meeting combinational preoperative and intraoperative MSIS criteria (rTKA: 16, 7.8%; rTHA: 13, 8.2%). Only 3.6% of all cases were considered "inconclusive" using preoperative and intraoperative data.

CONCLUSIONS

Given the high rate of cases satisfying PJI criteria during preoperative workup using our available tests, the synovial alpha-defensin and synovial CRP tests may not be necessary in the routine diagnostic workup of PJI. We suggest that the primary PJI workup process should be based on a stepwise algorithmic approach with the most economical testing necessary to determine a diagnosis first. The use of advanced, commercialized, and costly biomarkers should be utilized only when traditional testing is indeterminate.

Evaluation of elevated serum apelin-13 and D-dimer concentrations in individuals diagnosed with pulmonary embolism

BACKGROUND

Given the limited specificity of D-dimer, there is a perceived need to discover a more precise marker for diagnosing individuals who are suspected of having pulmonary embolism (PE). In this study, by evaluating the increase in the serum level of Apelin-13 and D-dimer, we found valuable findings about Apelin-13, which can be suggested as an auxiliary and non-invasive diagnostic biomarker in individuals with suspected PE, based on the obtained results.

METHODS

In this case-control study, 52 Iranian individuals were included, all of whom were suspected to have PE. These individuals were then divided into two groups based on the results of CT angiography, which is considered the gold standard imaging method for diagnosing PE. The two groups were patients with PE and patients without PE. Finally, the levels of certain markers in the serum were compared between the two groups.

RESULTS

The mean serum D-dimer levels in patients with PE were significantly elevated (p < 0.001) in comparison to those without PE (1102.47 to 456.2 ng/ml). Furthermore, the mean level of Apelin-13 was significantly higher in patients with PE (49.8 to 73.11 ng/L) (p < 0.001). The cutoff point of Apelin-13 has been calculated at 58.50 ng/ml, with 90.9% sensitivity and 90% specificity. The D-dimer cutoff point was 500 ng/ml, with 95.5% sensitivity and 43.3% specificity.

CONCLUSIONS

Based on the results of this study, the serum level of Apelin-13 can be used as a novel diagnostic and screening biomarker in patients with pulmonary thromboembolism.

Is the Habitual Dietary Intake of Foods of Plant or Animal Origin Associated with Circulating Hemostatic Factors?-Results of the Population-Based KORA-Fit Study

Blood coagulation is a complex physiological process critical for maintaining hemostasis, and disruptions in this system can lead to various health complications. Since the effects of specific food groups on a series of circulating coagulation parameters in the population are not well established, this study examines such associations in the population-based KORA-Fit study. A total of 595 subjects (263 men and 332 women) born between 1945 and 1964 and living in the study region of Augsburg were included in the study. Habitual food intake was estimated based on a combination of repeated 24-h food lists (24HFLs) and a food frequency questionnaire (FFQ). Antithrombin III, D-dimers, factor VIII, fibrinogen, protein C, protein S, aPTT, Quick value and INR were measured in citrate plasma. Multivariable linear regression models were applied to investigate associations between the consumption of specific foods of plant or animal origin and hemostatic factors. We found that the consumption of plant-based food groups, including green leafy vegetables (rich in vitamin K1), were hardly associated with coagulation parameters. Surprisingly, a high consumption of dairy products and especially butter were associated with higher D-dimer concentrations. These findings need further evaluation in prospective studies.

Deep vein thrombosis and pulmonary embolism: a prospective, observational study to evaluate diagnostic performance of the Tina-quant D-Dimer Gen.2 assay

Background

D-Dimer testing is a diagnostic tool for exclusion of deep vein thrombosis (DVT) and pulmonary embolism (PE). This study evaluated the diagnostic performance of the Tina-quant® D-Dimer Gen.2 assay (Roche Diagnostics International Ltd, Rotkreuz, Switzerland) in patients with low/intermediate pre-test probability of DVT/PE using standard, age-, and clinical probability-adjusted cut-offs.

Methods

In this prospective, observational, multicenter study (July 2017-August 2019), plasma samples were collected from hospital emergency departments and specialist referral centers. DVT/PE was diagnosed under hospital standard procedures and imaging protocols. A standard D-dimer cut-off of 0.5 µg fibrinogen equivalent units (FEU)/ml was combined with the three-level Wells score; cut-offs adjusted for age (age × 0.01 µg FEU/ml for patients >50 years) and clinical probability (1 µg FEU/ml for low probability) were also evaluated. An assay comparison was conducted in a subset of samples using the Tina-quant D-Dimer Gen.2 assay and the previously established routine laboratory assay, STA-Liatest D-Di Plus assay (Stago Deutschland GmbH, Düsseldorf, Germany).

Results

2,897 patients were enrolled; 2,516 completed the study (DVT cohort: 1,741 PE cohort: 775). Clinical assessment plus D-dimer testing using the standard cut-off resulted in 317 (DVT) and 230 (PE) false positives, and zero (DVT) and one (PE) false negatives. Negative predictive value (NPV) was 100.0% (95% confidence interval [CI]: 99.7%-100.0%) and 99.8% (95% CI: 98.8%-100.0%) for DVT and PE, respectively. After age-adjustment, NPV was 99.9% (95% CI: 99.6%-100.0%) and 99.1% (95% CI: 97.8-99.7) for DVT and PE, respectively. False positive rates decreased (>50%) in clinical probability-adjusted analyses vs. primary analysis. In the assay comparison, the performances of the two assays were comparable.

Conclusion

The Tina-quant D-Dimer Gen.2 assay and standard D-dimer cut-off level combined with the three-level Wells score accurately identified patients with a very low probability of DVT/PE.

PrEdictive value of coMbined pre-test proBability and blOod gas anaLysis In pulmonary emboliSM-the EMBOLISM study

In patients with suspected pulmonary embolism (PE), the number of unnecessary computed tomography pulmonary angiography (CTPA) scans remains high, especially in patients with low pre-test probability (PTP). So far, no study showed any additional benefit of capillary blood gas analysis (BGA) in diagnostic algorithms for PE. In this retrospective analysis of patients with suspected PE and subsequent CTPA, clinical data, D-dimer levels and BGA parameters (including standardized PaO2) were analyzed. Logistic regression analyses were performed to identify independent predictors for PE and reduce unnecessary CTPA examinations in patients with low PTP according to Wells score. Of 1538 patients, PE was diagnosed in 433 patients (28.2%). The original Wells score (odds ratio: 1.381 [95% CI 1.300-1.467], p < 0.001) and standardized PaO2 (odds ratio: 0.987 [95% CI 0.978-0.996], p = 0.005) were independent predictors for PE. After cohort adjustment for low PTP a D-dimer cut-off < 1.5 mg/L (278 patients (18.1%) with 18 PE (6.5%)) was identified in which a standardized PaO2 > 65 mmHg reduced the number of unnecessary CTPA by 31.9% with a 100% sensitivity. This approach was further validated in additional 53 patients with low PTP. In this validation group CTPA examinations were reduced by 32.7%. No patient with PE was missed. With our novel algorithm combining BGA testing with low PTP according to Wells score, we were able to increase the D-Dimer threshold to 1.5 mg/L and reduce CTPA examinations by approximately 32%.

Urine testing is associated with inappropriate antibiotic use and increased length of stay in emergency department patients

Background

Exposing patients with a low probability of disease to diagnostic testing with poor test characteristics leads to false positive results. Providers often act on these false results, which can cause unnecessary evaluation and treatment. The treatment of asymptomatic bacteriuria is discouraged, but it still frequently occurs in the inpatient setting; it is less studied in the Emergency Department (ED). In this study, we examine associations between urine testing, inappropriate antibiotic use, and length of stay in discharged ED patients at risk of urinary tract infection (UTI) misdiagnosis.

Methods

A cohort of discharged ED patients at risk of UTI misdiagnosis was created by pulling visit information for patients presenting with abdominal pain, chest pain, headache, vaginal bleeding in pregnancy, and elderly females with weakness or confusion. Predictors of urine testing, and urinary tract infection treatment were determined with logistic regression analysis. A chart review of a representative sample of this cohort was then completed screening for the presence of urinary tract symptoms and urine culture results. Linear regression analysis was then used to generate an adjusted mean difference in length of stay between patients who had urine testing compared to those who did not.

Results

About a quarter of chest pain and headache patients had urine testing, while approximately 75% of abdominal pain patients, vaginal bleeding in pregnancy, and elderly females with weakness or confusion did. Except for chest pain patients, the UTI treatment rate was more than double the positive culture rate, indicating overtreatment. A diagnosis of UTI is based on a combination of UTI symptoms and positive urine cultures, yet only about 15% of patients treated for UTI met these criteria. Lastly, in all chief complaint groups, the length of stay was significantly longer-30 min or more-for those who had urine testing compared to matched controls.

Conclusions

In this observational study of patients at risk of UTI misdiagnosis, urine testing was associated with inappropriate antibiotic use and delayed discharge. There is pressure on providers to perform diagnostic testing, but in patients without specific UTI symptoms, urine testing might cause more harm than benefit.

Hemostatic parameters in patients with spinal cord injury in subacute and chronic phase of the rehabilitation

Objective: The goal of this study was to measure hemostatic markers after SCI.Design: Assesing changes in coagulation and fibrynilitic system in SCI patients in different time post injury to Cross-sectional study.Setting: Rehabilitation Department of the Bydgoszcz University Hospital, Poland from 2011 to 2017.Participants: SCI patient during acute and chronic rehabilitation (N = 88).Outcome Measures: Assesing following parameters: platelet counts and levels of D-dimer, antithrombin III (ATIII), tissue factor (TF), tissue factor pathway inhibitor (TFPI) and the inflammatory marker, C-reactive protein (CRP).Interventions: Eighty-eight SCI patients were divided into three groups based on the time elapsed from injury: group I (three weeks to three months), group II (three to twelve months) and group III (more than twelve months). All patients underwent ultrasonography (US) to detect acute or chronic recanalized deep vein thrombosis (DVT). Platelet counts and levels of D-dimer, ATIII, TF, TFPI and CRP were assessed. TF and TFPI levels were measured in the control group of forty healthy individuals without SCI, the rest of the parameters were compared to laboratory norms.Results: D-dimer levels were significantly higher in group I compared to group II (P = .0002) and group III (P < .001). Group II had higher D-dimer levels than group III (P = .032). TFPI levels were higher in group II compared with group III (P = .0041) and control group (P = .000033). TF was significantly higher in all the SCI groups compared with the control group (P < .001).Conclusions: D-dimer and TF levels were still elevated twelve months after SCI. TF levels were also elevated over 12 months after inury. The results may indicate that sub-acute and even chronic SCI patients have disturbed coagulation and fibrynolitic system.

Diagnostic Value of Neutrophil Lymphocyte Ratio and D-Dimer as Biological Markers of Deep Vein Thrombosis in Patients Presenting with Unilateral Limb Edema

Introduction

Patients with deep vein thrombosis (DVT) pose high morbidity and mortality risk thus needing fast and accurate diagnosis. Wells clinical prediction scores with D-dimer testing are traditionally used to rule out patients with low probability of DVT. However, D-dimer testing has a few limitations regarding its relatively low specificity. Neutrophil-lymphocyte ratio (NLR), a marker of inflammation, was found to increase in DVT. Hence, we aimed to evaluate the role of NLR for DVT diagnosis.

Methods

Data were collected from medical records of patients with suspected DVT at Cipto Mangunkusumo National General Hospital during January–December 2014. Diagnosis of DVT was conducted using lower limb ultrasonography. Diagnostic values for NLR, D-dimer, and NLR + D-dimer were determined by receiver operating characteristic (ROC) analysis to obtain area under the curve (AUC), sensitivity, specificity, negative predictive value, and positive predictive values. Sensitivity and specificity analyses of NLR and D-dimer were also conducted based on Wells score and divided into groups of low and high probability of DVT.

Results

The AUC values for NLR, D-dimer, and NLR + D-dimer were 72.6%, 70.4%, and 76.1%, respectively. The optimal cut-off value determined for NLR was 5.12 with sensitivity of 67.7%, specificity of 67.9%, PPV of 68.85%, and NPV of 64.91% in differentiating subjects with and without DVT. This study also found that D-dimer had sensitivity of 69.4%, specificity of 71.4%, PPV of 72.88%, and NPV of 67.8%. Meanwhile, the NLR + D-dimer combination had sensitivity of 66.1% and specificity of 72.6%. Multivariate analysis showed that NLR (OR: 2.636; 95% CI: 1.144–6.076; p: 0.023) and D-dimer (OR: 4.175; 95% CI: 1.810–9.633; p: 0.001) were associated with DVT.

Conclusion

NLR value has wider AUC than D-Dimer and is relatively easier to obtain and does not require specific assay, thus enabling rapid evaluation of symptomatic patients suspected of having DVT. Adding NLR to D-dimer increased AUC to detect DVT. Therefore, NLR could serve as a complementary diagnostic tool for D-dimer to exclude DVT, especially in low clinical probability patients.

Predictors of venous thromboembolism in patients with COVID-19 in an underserved urban population: A single tertiary center experience

Introduction

Venous thromboembolism (VTE) is reported in up to 27% of patients with COVID‐19 due to SARS‐CoV‐2 infection. Dysregulated systemic inflammation and various patient traits are presumed to underlie this anomaly. Optimal VTE prophylaxis in COVID‐19 patients has not been established due to a lack of validated models for predicting VTE in this population. Our study aims to address this deficiency by identifying demographic and clinical characteristics of COVID‐19 patients associated with increased VTE risk.

Methods

This study is a retrospective analysis of all adult patients (final sample, n = 355) hospitalized with confirmed COVID‐19 at Einstein Medical Center Philadelphia between March 1 and April 24, 2020. Demographic and clinical patient data were collected and factors associated with VTE were identified and analyzed using t‐tests, multivariable logistic regression, and receiver operating characteristic (ROC) curves.

Results

Thirty patients (8.5%) developed VTE. Patients with VTE had significantly higher D‐dimer levels on admission (P = 0.045) and peak D‐dimer levels (P < 0.0001), in addition to higher rates of vasopressor requirements (P = 0.038), intubation (P = 0.003), and death (P = 0.023). Age (OR 1.042), obstructive sleep apnea (OR 5.107), and need for intubation (OR 3.796) were associated with significantly increased odds of VTE. Peak D‐dimer level was a good predictor of VTE (AUC 0.806, P < 0.0001) and a D‐dimer cutoff of >6640 ng/mL had high (>70%) sensitivity and specificity for VTE.

Conclusion

Peak D‐dimer level may be the most reliable clinical marker in COVID‐19 patients for predicting VTE and future prospective studies should attempt to further validate this.

Prognostic Value of Cardiovascular Biomarkers in COVID-19: A Review

In early December 2019, the coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) first emerged in Wuhan, China. As of May 10th, 2020, a total of over 4 million COVID-19 cases and 280,000 deaths have been reported globally, reflecting the raised infectivity and severity of this virus. Amongst hospitalised COVID-19 patients, there is a high prevalence of established cardiovascular disease (CVD). There is evidence showing that COVID-19 may exacerbate cardiovascular risk factors and preexisting CVD or may lead to cardiovascular complications. With intensive care units operating at maximum capacity and such staggering mortality rates reported, it is imperative during this time-sensitive COVID-19 outbreak to identify patients with an increased risk of adverse outcomes and/or myocardial injury. Preliminary findings from COVID-19 studies have shown the association of biomarkers of acute cardiac injury and coagulation with worse prognosis. While these biomarkers are recognised for CVD, there is emerging prospect that they may aid prognosis in COVID-19, especially in patients with cardiovascular comorbidities or risk factors that predispose to worse outcomes. Consequently, the aim of this review is to identify cardiovascular prognostic factors associated with morbidity and mortality in COVID-19 and to highlight considerations for incorporating laboratory testing of biomarkers of cardiovascular performance in COVID-19 to optimise outcomes.

The Burden of Unnecessary Testing From a Regularly Ordered Laboratory Assay: Age-Adjusted d-Dimer Quality Improvement Study

Diagnosing acute pulmonary embolism (PE) involves clinical suspicion in combination with sequential diagnostic tests including d-dimer laboratory assays. Although the sensitivity of this assay is well validated and thoroughly tested, a false-positive result can lead to unnecessary and costly testing. The age-adjusted d-dimer (AADD) has been suggested in the literature to improve the usefulness of d-dimer cutoffs and safely decrease iodine and radiation exposure associated with definitively ruling out PE with computed tomographic angiography (CTA).¹ We present an internal retrospective review utilizing the novel AADD cutoff to rule out PE and evaluate the potential extent of unnecessary testing with CTA. Using the AADD cutoff would have led to a 21.2% reduction in computerized tomography pulmonary embolus protocol. This internal quality improvement study suggests that changing our institutional conventional d-dimer to the novel AADD would provide a superior quality and cost–benefit.

Andexanet alfa for reversal of factor Xa inhibitor-associated anticoagulation

Background:

Review of clinical data on andexanet alfa for the reversal of factor Xa (FXa) inhibitor associated anticoagulation.

Data sources:

In the present review, we identified articles via PubMed using the combined keywords andexanet alfa, apixaban, enoxaparin, edoxaban, and rivaroxaban. Additional online searches via PubMed, Google Scholar, and Lexicomp were conducted for both prescribing and cost information. Portola Pharmaceuticals was contacted for information used for United States Food and Drug Administration approval of andexanet alfa.

Study selection and data extraction:

English-language clinical trials and reviews published between January 2008 and April 2019 were included for review. Bibliographies of selected articles were reviewed manually for relevant publications, focusing on reversal strategies for apixaban, enoxaparin, edoxaban, or rivaroxaban associated anticoagulation using andexanet alfa. Review articles were excluded.

Data synthesis:

The safety and tolerability of andexanet alfa were evaluated in one phase I, two phase II, and one phase III clinical trials. The use of andexanet alfa for reversing FXa inhibitor-associated anticoagulation were evaluated in the phase III ANNEXA-4 study.

Conclusions:

Studies evaluating laboratory parameters for coagulation show that andexanet alfa rapidly neutralizes the anticoagulant effects of apixaban, enoxaparin, edoxaban, and rivaroxaban. Clinical studies show that andexanet alfa improves markers related to coagulation, and reverses major bleeding in healthy volunteers and patients with life-threatening bleeding. Interruption of anticoagulation may result in thromboembolic and ischemic events. The use of andexanet alfa requires close monitoring for signs and symptoms of thromboembolic events, ischemic events, and cardiac arrest. Furthermore, anticoagulation should be resumed following the administration of andexanet alfa as soon as medically appropriate.

The D-dimer assay

D-dimer is an indirect marker of fibrinolysis and fibrin turnover; this molecule exhibits unique properties as a biological marker of hemostatic abnormalities as well as an indicator of intravascular thrombosis. D-dimer is a soluble fibrin degradation product that results from the systematic degradation of vascular thrombi through the fibrinolytic mechanism. Because of this, the D-dimer serves as a valuable marker of activation of coagulation and fibrinolysis in a number of clinical scenarios. Most commonly, D-dimer has been extensively investigated for excluding the diagnosis of venous thromboembolism (VTE) and is used routinely for this indication. In addition, D-dimer has been evaluated for determining the optimal duration of anticoagulation in VTE patients, for diagnosing and monitoring disseminated intravascular coagulation, and for monitoring other conditions in which the patient is at high risk of bleeding or thrombosis. Limitations of the assay include D-dimer elevation in a constellation of clinical scenarios (age, pregnancy, and cancer) and lack of clinical standardization.

Diagnosis of pulmonary embolism: Following the evidence from suspicion to certainty

Accurate, timely and cost-effective identification of pulmonary embolism remains a diagnostic challenge. This article reviews the pulmonary embolism diagnostic process with a focus on the best practice advice from the American College of Physicians. Benefits and risks of each diagnostic step are discussed. Emerging diagnostic tools, not included in the algorithm, are briefly reviewed.

Overdiagnosis of pulmonary embolism: definition, causes and implications

Overuse of computed tomography pulmonary angiography to diagnose pulmonary embolism in people who have only a low pre-test probability of pulmonary embolism has received significant attention in the past. The issue of overdiagnosis of pulmonary embolism, a potential consequence of overtesting, has been less explored. The term “overdiagnosis”, used in a narrow sense, describes a correct (true positive) diagnosis in a person but without any associated harm. The aim of this review is to summarise literature on the topic of overdiagnosis of pulmonary embolism and translate this epidemiological concept into the clinical practice of respiratory professionals. The review concludes that the location of pulmonary embolism at a subsegmental level, rather than whether a diagnosis was made incidentally or following an investigation for suspected pulmonary embolism, is the best predictor for situations in which anticoagulation may not be necessary. In the absence of strong evidence of the optimal management of subsegmental pulmonary embolism, treatment decisions should be made case by case, taking into account the patient's situation and preference.

A suggested definition of overdiagnosis of pulmonary embolism: a diagnosis of pulmonary embolism that, if left untreated, would not lead to more harm than if it were treated with anticoagulation therapy, independent of symptomshttp://ow.ly/wgAK30nr5IV

Performance of wells score to predict deep vein thrombosis and pulmonary embolism in endurance athletes

INTRODUCTION

There are an increasing number of reports describing deep vein thrombosis (DVT) and/or pulmonary embolism (PE) in otherwise healthy endurance athletes. The Wells score is the most commonly used clinical prediction rule to diagnose DVT/PE in clinical populations. However, the Wells score may have limited utility for recognition of DVT/PE in athletes, contributing to missed or delayed diagnosis.

OBJECTIVE

We performed an analysis of the ability of the Wells score to identify DVT/PE events in athletes through a review of published case reports.

METHODS

A systematic search of the literature yielded 11 case reports.

RESULTS

The Wells score had a 100% failure rate in identifying athletes with DVT (0/6) and PE (0/5), resulting in a delayed diagnosis for DVT of 20 ± 14 days. Retrospectively removing 'differential diagnosis' from the clinical prediction rule for DVT changed the Wells score median from 0 (range: -1 to 0) to 2 (range: 1 to 2); the threshold for predicting DVT as 'likely'. There were limited clinical characteristics captured in the Wells score for PE that were applicable to athletes, highlighting the need for reappraisal. Although the Wells score failed to accurately triage athletes with known DVT and/or PE, the addition of a D-dimer value (mean: 1566 ± 758ng/dL) to the Wells score correctly identified 9/9 athletes.

CONCLUSIONS

The Wells score had a 100% failure rate for triaging athletes with known DVT/PE. When performed, D-dimer adequately facilitated the additional diagnostic testing required for a timely diagnosis of DVT/PE in athletes. Improving awareness of an atypical presentation of thrombotic events in athletes may reduce the widespread underestimation of DVT/PE among athletes and facilitate the additional testing required for a timely diagnosis.

Cardiopulmonary laboratory biomarkers in the evaluation of acute dyspnea

Dyspnea is a common chief complaint in the emergency department, with over 4 million visits annually in the US. Establishing the correct diagnosis can be challenging, because the subjective sensation of dyspnea can result from a wide array of underlying pathology, including pulmonary, cardiac, neurologic, psychiatric, toxic, and metabolic disorders. Further, the presence of dyspnea is linked with increased mortality in a variety of conditions, and misdiagnosis of the cause of dyspnea leads to poor patient-level outcomes. In combination with the history and physical, efficient, and focused use of laboratory studies, the various cardiopulmonary biomarkers can be useful in establishing the correct diagnosis and guiding treatment decisions in a timely manner. Use and interpretation of such tests must be guided by the clinical context, as well as an understanding of the current evidence supporting their use. This review discusses current standards and research regarding the use of established and emerging cardiopulmonary laboratory markers in the evaluation of acute dyspnea, focusing on recent evidence assessing the diagnostic and prognostic utility of various tests. These markers include brain natriuretic peptide (BNP) and N-terminal prohormone (NT-proBNP), mid-regional peptides proatrial NP and proadrenomedullin, cardiac troponins, D-dimer, soluble ST2, and galectin 3, and included is a discussion on the use of arterial and venous blood gases.

Postoperative Acute Pulmonary Embolism Following Pulmonary Resections

Postoperative acute pulmonary embolism after pulmonary resections is highly fatal complication. Many literatures have documented cancer to be the highest risk factor for acute pulmonary embolism after pulmonary resections. Early diagnosis of acute pulmonary embolism is highly recommended and computed tomographic pulmonary angiography is the gold standard in diagnosis of acute pulmonary embolism. Anticoagulants and thrombolytic therapy have shown a great success in treatment of acute pulmonary embolism. Surgical therapies (embolectomy and inferior vena cava filter replacement) proved to be lifesaving but many literatures favored medical therapy as the first choice. Prophylaxis pre and post operation is highly recommended, because there were statistical significant results in different studies which supported the use of prophylaxis in prevention of acute pulmonary embolism. Having reviewed satisfactory number of literatures, it is suggested that thoroughly preoperative assessment of patient conditions, determining their risk factors complicating to pulmonary embolism and the use of appropriate prophylaxis measures are the key options to the successful minimization or eradication of acute pulmonary embolism after lung resections.

Comparison of Wells and Revised Geneva Rule to Assess Pretest Probability of Pulmonary Embolism in High-Risk Hospitalized Elderly Adults

OBJECTIVES

To assess and compare the diagnostic power for pulmonary embolism (PE) of Wells and revised Geneva scores in two independent cohorts (training and validation groups) of elderly adults hospitalized in a non-emergency department.

DESIGN

Prospective clinical study, January 2011 to January 2013.

SETTING

Unit of Internal Medicine inpatients, University of Catania, Italy.

PARTICIPANTS

Elderly adults (mean age 76 ± 12), presenting with dyspnea or chest pain and with high clinical probability of PE or D-dimer values greater than 500 ng/mL (N = 203), were enrolled and consecutively assigned to a training (n = 101) or a validation (n = 102) group. The clinical probability of PE was assessed using Wells and revised Geneva scores.

MEASUREMENTS

Clinical examination, D-dimer test, and multidetector computed angiotomography were performed in all participants. The accuracy of the scores was assessed using receiver operating characteristic analyses.

RESULTS

PE was confirmed in 46 participants (23%) (24 training group, 22 validation group). In the training group, the area under the receiver operating characteristic curve was 0.91 (95% confidence interval (CI) = 0.85-0.98) for the Wells score and 0.69 (95% CI = 0.56-0.82) for the revised Geneva score (P < .001). These results were confirmed in the validation group (P < .05). The positive (LR+) and negative likelihood ratios (LR-) (two indices combining sensitivity and specificity) of the Wells score were superior to those of the revised Geneva score in the training (LR+, 7.90 vs 1.34; LR-, 0.23 vs 0.66) and validation (LR+, 13.5 vs 1.46; LR-, 0.47 vs 0.54) groups.

CONCLUSION

In high-risk elderly hospitalized adults, the Wells score is more accurate than the revised Geneva score for diagnosing PE.

Cardiac-targeting transfection of tissue-type plasminogen activator gene to prevent the graft thrombosis and vascular anastomotic restenosis after coronary bypass

AIM

To observe the tissue-type plasminogen activator gene (t-PA) plasmid packaged with albumin nanoparticles crosslinked to albumin ultrasound microbubbles for targeting transfection to myocardium to prevent the graft thrombosis and vascular anastomotic restenosis after coronary bypass.

METHODS

A dog model of coronary bypass using the autoallergic saphenous vein as the graft was made. A highly expressive t-PA gene plasmid packaged with albumin nanoparticles crosslinked to albumin ultrasound microbubbles was constructed. Targeting myocardial transfection was performed with this gene vector under the aid of therapeutic ultrasound(1MHz, 1.5 w/cm2, 6minutes, intravenously) after the bypass. The expression of t-PA in myocardium was detected with a multiclonal antibody to t-PA by the indirect immunohistochemical method. Venous blood t-PA and D-dimer contents were tested before and 1, 2 and 4weeks after the operation. The effects of this gene vector on thrombosis of the grafts and the coronary intimal hyperplasia around the anastomotic stoma were observed using a routine pathological examination, a morphometry for intimal thickness and area and the immuno-histochemical stain with a monoclonal antibody to PCNA for estimating the intimal SMC proliferation.

RESULTS

The effective expression of t-PA protein by myocardium was obtained, followed by the persistent raises of blood t-PA and D-dimer 1, 2 and 4weeks after the transfection. Thrombosis of the grafts was successfully restrained. The expression of PCNA by coronary intimal vSMCs and intimal hyperplasia were remarkablely reduced.

CONCLUSION

This t-PA gene targeting vector could be used to prevent the dog thrombosis, which provided the experimental identification for prevention on human thrombotic diseases.

Pulmonary embolism in Bradford, UK: role of end-tidal CO2 as a screening tool

End-tidal CO2 (ETCO2) can represent dead space ventilation. The authors aimed to define the optimum ETCO2 to conclusively exclude a pulmonary embolic event. One hundred consecutive patients with suspected pulmonary embolisms (PEs) were enrolled over 6 months in 2012. Symptoms, demographic date, Wells' score, D-dimer levels and the gold standard computed tomography pulmonary angiogram (CTPA) results were collated for analysis. ETCO2 was measured within 24 hours of presentation in all 100 patients. Patient ages ranged from 18 years to 93 years. PE was diagnosed in 38% of cases. The average ETCO2 in patients with a positive CTPA was 3.35 kPa (range 2.4-4.2 kPa, SD 0.50). The average ETCO2 in patients without a PE was 4.41 kPa (range 1.3-6.6 kPa, SD 1.10). All patients positive for a PE obtained an ETCO2 <4.3 kPa (32.3 mmHg). This point (4.3 kPa) had a sensitivity and specificity (100% and 68% respectively), with a negative predictive value of 100% and positive predictive value of 66%. ETCO2 may reliably be used to screen and exclude patients with suspected PEs. If used in combination with D-dimer with clinical probability as a screening tool, CTPA will be required in only a minority of patients.

Evaluation of the utility of the Wells score in predicting pulmonary embolism in patients admitted to a spine surgery service

STUDY DESIGN

A retrospective medical chart review of 4179 patients admitted to the spine surgery service.

OBJECTIVE

To evaluate the utility of the Wells score in predicting pulmonary embolism (PE) in patients admitted to a spine surgery service.

SUMMARY OF BACKGROUND DATA

The decision to perform computed tomography pulmonary angiography (CTPA) to diagnose PE in patients who have undergone spine surgery requires consideration of multiple factors: false-positive CTPA results may lead to unnecessary anticoagulation treatment, and computed tomography scans are costly and expose patients to ionizing radiation. The Wells score was developed to assign risk categories to patients with suspected PE and thereby indicate the need for CTPA. However, the utility of the Wells score in predicting the likelihood of PE, specifically in spine surgery patients, has not been described to date. We identified all patients who were admitted to the spine surgery service at our institution from January 1, 2001 to December 31, 2011 and underwent CTPA. Each patient's CTPA result was classified as positive or negative for PE, and the reason for ordering the CTPA was recorded. The Wells score was calculated retrospectively for each patient, and risk categories were assigned by using the traditional and alternative interpretations of the Wells score. The reason for the CTPA, the Wells score, and Wells risk category were compared for patients who were classified as being positive or negative for PE.

RESULTS

Sixty-six of the 4179 patients who were admitted to the spine surgery service underwent CTPA for suspected PE. Nineteen of the 66 patients (28.8%) were diagnosed with acute PE, and the overall PE rate was 0.45% (19 of 4179 patients). The mean Wells score for patients diagnosed with PE was 5.3, whereas the mean score for the remaining patients was 4.9 (P = 0.793). Neither the traditional nor the alternative interpretation of the Wells score was predictive of PE (P = 0.394 and P = 0.178, respectively). Our study examined the utility of the Wells score in predicting PE in spine surgery patients.

CONCLUSION

The results of the CTPA did not show a significant correlation with the Wells score or the reason for the test. Our findings indicate the need to develop a predictive scoring system that assesses the risk of PE and assists in the decision-making process for ordering CTPA in spine surgery patients.

Specificity of quantitative latex agglutination assay for D-dimer in exclusion of pulmonary embolism in the emergency department

We assessed the prevalence of elevated quantitative latex agglutination assay for D-dimer in patients in the emergency department in whom pulmonary embolism (PE) was excluded. D-dimer was normal (<230 ng/mL) in 435 (83%) of the 522 patients. D-dimer was normal in 88% of the patients with musculoskeletal or related chest pain, 74% with pleurisy or pleuritic chest pain, and 85% with upper respiratory tract infection. D-dimer was 230 to 500 ng/mL in 65 (75%) of the 87 in whom D-dimer was elevated. Clinical probability was low in 31 (48%) of the 65 patients with D-dimer levels of 230 to 500 ng/mL. D-dimer was 230 to 500 ng/mL and clinical probability was low in 31 (36%) of the 87 patients who had computed tomographic (CT) angiograms because of elevated D-dimer. Negative likelihood ratio for PE is sufficiently low that PE can be excluded with reasonable certainty in such patients. Tailoring cutoff value to 500 ng/mL in patients with low clinical probability would have reduced CT angiograms by 36%.

Management of venous thromboembolism

This article describes the risk factors, diagnostic tools, and therapeutic approaches for venous thromboembolism (VTE), which includes primarily deep vein thrombosis and pulmonary embolism, as well as VTE occurring at other sites. Outpatient management strategies are emphasized.

Ultrasound-targeted transfection of tissue-type plasminogen activator gene carried by albumin nanoparticles to dog myocardium to prevent thrombosis after heart mechanical valve replacement

Background

There are more than 300,000 prosthetic heart valve replacements each year worldwide. These patients are faced with a higher risk of thromboembolic events after heart valve surgery and long-term or even life-long anticoagulative and antiplatelet therapies are necessary. Some severe complications such as hemorrhaging or rebound thrombosis can occur when the therapy ceases. Tissue-type plasminogen activator (t-PA) is a thrombolytic agent. One of the best strategies is gene therapy, which offers a local high expression of t-PA over a prolonged time period to avoid both systemic hemorrhaging and local rebound thrombosis. There are some issues with t-PA that need to be addressed: currently, there is no up-to-date report on how the t-PA gene targets the heart in vivo and the gene vector for t-PA needs to be determined.

Aims

To fabricate an albumin nano-t-PA gene ultrasound-targeted agent and investigate its targeting effect on prevention of thrombosis after heart mechanic valve replacement under therapeutic ultrasound.

Methods

A dog model of mechanical tricuspid valve replacement was constructed. A highly expressive t-PA gene plasmid was constructed and packaged by nanoparticles prepared with bovine serum albumin. This nanopackaged t-PA gene plasmid was further cross-linked to ultrasonic microbubbles prepared with sucrose and bovine serum albumin to form the ultrasonic-targeted agent for t-PA gene transfection. The agent was given intravenously followed by a therapeutic ultrasound treatment (1 MHz, 1.5 w/cm², 10 minutes) of the heart soon after valve replacement had been performed. The expression of t-PA in myocardium was detected with multiclonal antibodies to t-PA by the indirect immunohistochemical method. Venous blood t-PA and D-dimer contents were tested before and 1, 2, 4, and 8 weeks after the operation.

Results

The high expression of t-PA could be seen in myocardium with increases in blood t-PA and D-dimer contents and thrombosis was prevented 8 weeks after operation.

Conclusion

We successfully fabricated an albumin nano-t-PA gene ultrasound-targeted agent that could prevent dog thrombosis after mechanical heart valve replacement. Our study provides an experimental basis for prevention of human thrombosis-related diseases.