Cost-Effectiveness of Performing Reference Ultrasonography in Patients with Deep Vein Thrombosis

BACKGROUND

 The diagnosis of recurrent ipsilateral deep vein thrombosis (DVT) with compression ultrasonography (CUS) may be hindered by residual intravascular obstruction after previous DVT. A reference CUS, an additional ultrasound performed at anticoagulant discontinuation, may improve the diagnostic work-up of suspected recurrent ipsilateral DVT by providing baseline images for future comparison.

OBJECTIVES

 To evaluate the cost-effectiveness of routinely performing reference CUS in DVT patients.

METHODS

 Patient-level data (n = 96) from a prospective management study (Theia study; NCT02262052) and claims data were used in a decision analytic model to compare 12 scenarios for diagnostic management of suspected recurrent ipsilateral DVT. Estimated health care costs and mortality due to misdiagnosis, recurrent venous thromboembolism, and bleeding during the first year of follow-up after presentation with suspected recurrence were compared.

RESULTS

 All six scenarios including reference CUS had higher estimated 1-year costs (€1,763-€1,913) than the six without reference CUS (€1,192-€1,474). Costs were higher because reference CUS results often remained unused, as 20% of patients (according to claims data) would return with suspected recurrent DVT. Estimated mortality was comparable in scenarios with (14.8-17.9 per 10,000 patients) and without reference CUS (14.0-18.5 per 10,000). None of the four potentially most desirable scenarios included reference CUS.

CONCLUSION

 One-year health care costs of diagnostic strategies for suspected recurrent ipsilateral DVT including reference CUS are higher compared to strategies without reference CUS, without mortality benefit. These results can inform policy-makers regarding use of health care resources during follow-up after DVT. From a cost-effectiveness perspective, the findings do not support the routine application of reference CUS.

Tailored anticoagulant treatment after a first venous thromboembolism: protocol of the Leiden Thrombosis Recurrence Risk Prevention (L-TRRiP) study - cohort-based randomised controlled trial

INTRODUCTION

Patients with a first venous thromboembolism (VTE) are at risk of recurrence. Recurrent VTE (rVTE) can be prevented by extended anticoagulant therapy, but this comes at the cost of an increased risk of bleeding. It is still uncertain whether patients with an intermediate recurrence risk or with a high recurrence and high bleeding risk will benefit from extended anticoagulant treatment, and whether a strategy where anticoagulant duration is tailored on the predicted risks of rVTE and bleeding can improve outcomes. The aim of the Leiden Thrombosis Recurrence Risk Prevention (L-TRRiP) study is to evaluate the outcomes of tailored duration of long-term anticoagulant treatment based on individualised assessment of rVTE and major bleeding risks.

METHODS AND ANALYSIS

The L-TRRiP study is a multicentre, open-label, cohort-based, randomised controlled trial, including patients with a first VTE. We classify the risk of rVTE and major bleeding using the L-TRRiP and VTE-BLEED scores, respectively. After 3 months of anticoagulant therapy, patients with a low rVTE risk will discontinue anticoagulant treatment, patients with a high rVTE and low bleeding risk will continue anticoagulant treatment, whereas all other patients will be randomised to continue or discontinue anticoagulant treatment. All patients will be followed up for at least 2 years. Inclusion will continue until the randomised group consists of 608 patients; we estimate to include 1600 patients in total. The primary outcome is the combined incidence of rVTE and major bleeding in the randomised group after 2 years of follow-up. Secondary outcomes include the incidence of rVTE and major bleeding, functional outcomes, quality of life and cost-effectiveness in all patients.

ETHICS AND DISSEMINATION

The protocol was approved by the Medical Research Ethics Committee Leiden-Den Haag-Delft. Results are expected in 2028 and will be disseminated through peer-reviewed journals and during (inter)national conferences.

TRIAL REGISTRATION NUMBER

NCT06087952.

Discharge from the emergency department and outpatient clinic in cancer patients with acute symptomatic and incidental pulmonary embolism: A multicenter retrospective cohort study

BACKGROUND

It is unclear how often cancer patients with acute pulmonary embolism (PE) are discharged from the emergency department (ED) or outpatient clinic and whether direct discharge is safe. We assessed treatment setting and early safety outcomes in cancer patients with acute symptomatic and incidental PE.

METHODS

Cancer patients diagnosed with PE at the ED or outpatient clinic between August 2017 and May 2021 were included in Four Cities VTE Cancer, a Dutch multicenter retrospective cohort study. The main outcome was direct discharge versus hospitalization. Safety outcomes were cumulative 14-day mortality and PE-related readmission incidences.

RESULTS

We included 602 patients (median age 71 years; 49.5 % female) of whom 285 (47.3 %) were discharged directly and 317 (52.7 %) were hospitalized. The cumulative 14-day mortality incidence was 0.7 % (95 % CI, 0.1-2.4 %) in patients discharged directly and 9.0 % (95 % CI, 6.2-12.5 %) in those hospitalized. The cumulative 14-day PE-related readmission incidence was 1.8 % (95 % CI, 0.7-3.9 %) and 1.4 % (95 % CI, 0.5-3.3 %) in directly discharged and hospitalized patients, respectively. Of the 220 patients with incidental PE, 180 (81.8 %) were discharged directly compared to 105 of 382 (27.5 %) patients with symptomatic PE (P < 0.001). Mortality and readmission incidences in symptomatic and incidental PE were consistent with the main analysis.

CONCLUSIONS

About 28 % and 82 % of cancer patients with symptomatic or incidental PE, respectively, were discharged directly, with low 14-day mortality and PE-related readmission incidences. These data underline the need for PE risk stratification in oncological populations and suggest that clinicians successfully identify a proportion of patients in whom direct discharge is safe.

Performance of the 4-Level Pulmonary Embolism Clinical Probability Score (4PEPS) in the diagnostic management of pulmonary embolism: An external validation study

BACKGROUND

The recently published 4-level Pulmonary Embolism Clinical Probability Score (4PEPS) integrates different aspects from currently available diagnostic strategies to further reduce imaging testing in patients with clinically suspected pulmonary embolism (PE).

AIM

To externally validate the performance of 4PEPS in an independent cohort.

METHODS

In this post-hoc analysis of the prospective diagnostic management YEARS study, the primary outcome measures were discrimination, calibration, efficiency (proportion of imaging tests potentially avoided), and failure rate (venous thromboembolism (VTE) diagnosis at baseline or follow-up in patients with a negative 4PEPS algorithm). Multiple imputation was used for missing 4PEPS items. Based on 4PEPS, PE was considered ruled out in patients with a very low clinical pre-test probability (CPTP) without D-dimer testing, in patients with a low CPTP and D-dimer <1000 μg/L, and in patients with a moderate CPP and D-dimer below the age-adjusted threshold.

RESULTS

Of the 3465 patients, 474 (14 %) were diagnosed with VTE at baseline or during 3-month follow-up. Discriminatory performance of the 4PEPS items was good (area under ROC-curve, 0.82; 95%CI, 0.80-0.84) as was calibration. Based on 4PEPS, PE could be considered ruled out without imaging in 58 % (95%CI 57-60) of patients (efficiency), for an overall failure rate of 1.3 % (95%CI 0.86-1.9).

CONCLUSION

In this retrospective external validation, 4PEPS appeared to safely rule out PE with a high efficiency. Nevertheless, although not exceeding the failure rate margin by ISTH standards, the observed failure rate in our analysis appeared to be higher than in the original 4PEPS derivation and validation study. This highlights the importance of a prospective outcome study.

Noninvasive diagnostic work-up for suspected acute pulmonary embolism during pregnancy: a systematic review and meta-analysis of individual patient data

BACKGROUND

Few studies evaluated the performance of noninvasive diagnostic strategies for suspected acute pulmonary embolism (PE) in pregnant women.

OBJECTIVES

The aim of this study was to establish the safety and efficiency of the Wells rule with fixed and adapted D-dimer threshold, and the YEARS algorithm, combined with compression ultrasonography (CUS), in pregnant women with suspected PE in an individual patient data meta-analysis.

METHODS

We performed a systematic review to identify prospective diagnostic management studies in pregnant women with suspected PE. Primary outcomes were safety, defined as the failure rate, ie, the 3-month venous thromboembolism (VTE) incidence after excluding PE without chest imaging, and efficiency, defined as the proportion of patients in whom chest imaging could be avoided.

RESULTS

We identified 2 relevant studies, of which individual patient-level data were analyzed in a fixed-effect meta-analysis, totaling 893 pregnant women. The Wells rule with fixed and adapted D-dimer threshold as well as the YEARS algorithm could safely rule out acute PE (failure rate, 0·37%-1·4%), but efficiency improved considerably when applying pretest probability-adapted D-dimer thresholds. The efficiency of bilateral CUS was limited (2·3% overall; number needed to test 43), especially in patients without symptoms of deep-vein thrombosis (efficiency 0·79%; number needed to test 127).

CONCLUSION

This study supports the latest guideline recommendations (European Society of Cardiology 2019) to apply pretest probability assessment and D-dimer tests to rule out PE in pregnant women. From an efficiency perspective, the use of a strategy with pretest probability-adapted D-dimer threshold is preferred. The yield of CUS was very limited in patients without concomitant symptoms of deep-vein thrombosis.

Use of the National Early Warning Score for predicting deterioration of patients with acute pulmonary embolism: a post-hoc analysis of the YEARS Study

BACKGROUND

The Pulmonary Embolism Severity Index (PESI) and the simplified PESI (sPESI) are validated scores for mortality prediction in patients with pulmonary embolism (PE). National Early Warning Score (NEWS) is a general prognostic risk score for multiple clinical settings. We investigated whether the NEWS had a comparable performance with the PESI and sPESI, for predicting intensive care unit (ICU) admission and death in patients with acute PE.

METHODS

In haemodynamically stable patients with confirmed PE from the YEARS Study (2013-2015), we evaluated the performance of the NEWS, PESI and sPESI for predicting 7-day ICU admission and 30-day mortality. Receiver operating characteristic curves were plotted and the area under the curve (AUC) was calculated.

RESULTS

Of 352 patients, 12 (3.4%) were admitted to the ICU and 5 (1.4%) died. The AUC of the NEWS for ICU admission was 0.80 (95% CI 0.66 to 0.94) and 0.92 (95% CI 0.82 to 1.00) for 30-day mortality. At a threshold of 3 points, NEWS yielded a sensitivity and specificity of 92% and 53% for ICU admission and 100% and 52% for 30-day mortality. The AUC of the PESI was 0.64 (95% CI 0.48 to 0.79) for ICU admission and 0.94 (95% CI 0.87 to 1.00) for mortality. At a threshold of 66 points, PESI yielded a sensitivity of 75% and a specificity of 38% for ICU admission. For mortality, these were 100% and 37%, respectively. The performance of the sPESI was similar to that of PESI.

CONCLUSION

In comparison with PESI and sPESI, NEWS adequately predicted 7-day ICU admission as well as 30-day mortality, supporting its potential relevance for clinical practice.

Diagnostic efficacy of ECG-derived ventricular gradient for the detection of chronic thromboembolic pulmonary hypertension in patients with acute pulmonary embolism

INTRODUCTION

Application of the chronic thromboembolic pulmonary hypertension (CTEPH) rule out criteria (manual electrocardiogram [ECG] reading and N-terminal pro-brain natriuretic peptide [NTproBNP] test) can rule out CTEPH in pulmonary embolism (PE) patients with persistent dyspnea (InShape II algorithm). Increased pulmonary pressure may also be identified using automated ECG-derived ventricular gradient optimized for right ventricular pressure overload (VG-RVPO).

METHOD

A predefined analysis of the InShape II study was performed. The diagnostic performance of the VG-RVPO for the detection of CTEPH and the incremental diagnostic value of the VG-RVPO as new rule-out criteria in the InShape II algorithm were evaluated.

RESULTS

60 patients were included; 5 (8.3%) were ultimately diagnosed with CTEPH. The mean baseline VG-RVPO (at time of PE diagnosis) was -18.12 mV·ms for CTEPH patients and - 21.57 mV·ms for non-CTEPH patients (mean difference 3.46 mV·ms [95%CI -29.03 to 35.94]). The VG-RVPO (after 3-6 months follow-up) normalized in patients with and without CTEPH, without a clear between-group difference (mean Δ VG-RVPO of -8.68 and - 8.42 mV·ms respectively; mean difference of -0.25 mV·ms, [95%CI -12.94 to 12.44]). The overall predictive accuracy of baseline VG-RVPO, follow-up RVPO and Δ VG-RVPO for CTEPH was moderate to poor (ROC AUC 0.611, 0.514 and 0.539, respectively). Up to 76% of the required echocardiograms could have been avoided with VG-RVPO criteria replacing the InShape II rule-out criteria, however at cost of missing up to 80% of the CTEPH diagnoses.

CONCLUSION

We could not demonstrate (additional) diagnostic value of VG-RVPO as standalone test or as on top of the InShape II algorithm.

Treatment of arterial calcification in patients with chronic limb threatening ischemia with etidronate: protocol of an investigator-initiated multicenter, double blind, placebo-controlled, randomized clinical trial

Background

Pathologic studies have shown that in patients with critical limb threatening ischaemia (CLTI) medial arterial calcifications are frequently found and may be responsible for aggravating the disease. These extensive calcifitcations are found not only in arteries of the leg but also in the coronary arteries and the aorta. The progression of these calcifications is fast and they stiffen the vessel wall and may thus increase the cardiovascular risk.

Reduction of progression of calcification may not only reduce the burden of CLTI but may also reduce the high residual cardiovascular risk. Medial calcifications have been halted by etidronate in other trials. Its potential to reduce the burden from peripheral vascular disease in CLTI and residual cardiovascular risk remains to be established.

Methods

This is an investigator-initiated multicenter, double blind, placebo-controlled, randomized trial comparing the effects of etidronate versus placebo in patients with CLTI.

Subjects will be randomized to either treatment with etidronate for 12 months (cyclical 20 mg/kg for 2 weeks on and 10 weeks off) orally or placebo for 12 months (in a similar routine).

The primary endpoint is the change in arterial calcification as quantified by CT-scan.

Secondary endpoints are the number of amputations above and below the ankle, mortality, number of vascular interventions and quality of life.

Discussion

Up to now, the inert end stage of vascular disease in patients with CLTI, has been considered calcification of vessel walls. We believe there is reason to reverse causation and hypothesize that calcification causes vascular disease. This reversal can be proven in a clinical trial if halting the calcification process improves the outcome of the patient. Therefore we use etidronate, a bisphosphate that has proven to stop the calcification in several rare monogenetic calcifying diseases. We aim to perform this mechanistic proof-of-concept study hopefully leading to a clinical outcome study later on.

Effect of an interactive, educational app about venous thromboembolism and anticoagulation on patient satisfaction: A randomized controlled trial

BACKGROUND

Adequate patient education is essential for patients to engage in shared decision-making when deciding to stop or continue anticoagulation after 3 months for venous thromboembolism (VTE). Our objectives were to evaluate the effect of an interactive, educational app on patients' level of satisfaction with information, perceived level of knowledge, decisional conflict and extent of shared decision-making when deciding on treatment duration of VTE.

MATERIALS AND METHODS

This randomized controlled trial in 1 academic and 3 general Dutch hospitals included adult patients diagnosed with VTE without malignancy or prolonged anticoagulation for other indications. Patients were randomized in 1:1 ratio to receive the app (intervention group) in addition to hospital-specific standard of care. The app, created for this study, contains information on VTE and anticoagulation on an interactive timeline. In the week preceding the consultation when treatment duration is decided, patients were provided with daily videos using push notifications. Outcomes were assessed through self-reported questionnaires at baseline, 1-2 days before and 1 day after consultation. Data were analyzed using t-tests and linear mixed models for repeated measurements.

RESULTS

Data of 56 patients were analyzed (mean age 57 ± 13; 27% female). On a numeric rating scale from 0 to 10, patients who received the app were 0.9 points (95%CI 0.0-1.7; p 0.04) more satisfied with the provided information. Patients who received the app experienced significantly less decisional conflict. No differences in other outcomes were observed.

CONCLUSIONS

An educational app about VTE and anticoagulation increases patients' satisfaction and reduces decisional conflict when deciding on treatment duration of VTE. This study was registered in the Netherlands Trial Register (NL7037).

Home Treatment Compared to Initial Hospitalization in Normotensive Patients with Acute Pulmonary Embolism in the Netherlands: A Cost Analysis

BACKGROUND

 Venous thromboembolism constitutes substantial health care costs amounting to approximately 60 million euros per year in the Netherlands. Compared with initial hospitalization, home treatment of pulmonary embolism (PE) is associated with a cost reduction. An accurate estimation of cost savings per patient treated at home is currently lacking.

AIM

 The aim of this study was to compare health care utilization and costs during the first 3 months after a PE diagnosis in patients who are treated at home versus those who are initially hospitalized.

METHODS

 Patient-level data of the YEARS cohort study, including 383 normotensive patients diagnosed with PE, were used to estimate the proportion of patients treated at home, mean hospitalization duration in those who were hospitalized, and rates of PE-related readmissions and complications. To correct for baseline differences within the two groups, regression analyses was performed. The primary outcome was the average total health care costs during a 3-month follow-up period for patients initially treated at home or in hospital.

RESULTS

 Mean hospitalization duration for the initial treatment was 0.69 days for those treated initially at home (n = 181) and 4.3 days for those initially treated in hospital (n = 202). Total average costs per hospitalized patient were €3,209 and €1,512 per patient treated at home. The adjusted mean difference was €1,483 (95% confidence interval: €1,181-1,784).

CONCLUSION

 Home treatment of hemodynamically stable patients with acute PE was associated with an estimated net cost reduction of €1,483 per patient. This difference underlines the advantage of triage-based home treatment of these patients.

Non-invasive early exclusion of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism: the InShape II study

BACKGROUND

The current diagnostic delay of chronic thromboembolic pulmonary hypertension (CTEPH) after pulmonary embolism (PE) is unacceptably long, causing loss of quality-adjusted life years and excess mortality. Validated screening strategies for early CTEPH diagnosis are lacking. Echocardiographic screening among all PE survivors is associated with overdiagnosis and cost-ineffectiveness. We aimed to validate a simple screening strategy for excluding CTEPH early after acute PE, limiting the number of performed echocardiograms.

METHODS

In this prospective, international, multicentre management study, consecutive patients were managed according to a screening algorithm starting 3 months after acute PE to determine whether echocardiographic evaluation of pulmonary hypertension (PH) was indicated. If the 'CTEPH prediction score' indicated high pretest probability or matching symptoms were present, the 'CTEPH rule-out criteria' were applied, consisting of ECG reading and N-terminalpro-brain natriuretic peptide. Only if these results could not rule out possible PH, the patients were referred for echocardiography.

RESULTS

424 patients were included. Based on the algorithm, CTEPH was considered absent in 343 (81%) patients, leaving 81 patients (19%) referred for echocardiography. During 2-year follow-up, one patient in whom echocardiography was deemed unnecessary by the algorithm was diagnosed with CTEPH, reflecting an algorithm failure rate of 0.29% (95% CI 0% to 1.6%). Overall CTEPH incidence was 3.1% (13/424), of whom 10 patients were diagnosed within 4 months after the PE presentation.

CONCLUSIONS

The InShape II algorithm accurately excluded CTEPH, without the need for echocardiography in the overall majority of patients. CTEPH was identified early after acute PE, resulting in a substantially shorter diagnostic delay than in current practice.

Safety of using the combination of the Wells rule and D-dimer test for excluding acute recurrent ipsilateral deep vein thrombosis

BACKGROUND

The diagnostic accuracy of clinical probability assessment and D-dimer testing for clinically suspected recurrent deep vein thrombosis (DVT) is largely unknown.

AIM

To evaluate the safety of ruling out acute recurrent DVT based on an unlikely Wells score for DVT and a normal D-dimer test.

METHODS

This was a predefined endpoint of the Theia study in which the diagnostic accuracy of magnetic resonance direct thrombus imaging in acute recurrent ipsilateral DVT was validated. The Wells rule and D-dimer test, performed as part of the study protocol, were not used for management decisions. The primary outcome of this analysis was the incidence of recurrent DVT at baseline or during 3-month follow-up for patients with an unlikely Wells score and a normal D-dimer test.

RESULTS

Results of both Wells score and D-dimer tests were available in 231 patients without anticoagulant treatment. The recurrent DVT prevalence was 45% (103/231). Forty-nine patients had an unlikely Wells score and normal D-dimer test, of whom 3 (6.1%, 95% confidence interval [CI] 1.3%-18%) had recurrent DVT at baseline/follow-up, yielding a sensitivity of 97% (95% CI 92%-99%) and specificity of 36% (95% CI 28%-45%). Thus, if clinical probability scoring and D-dimer testing would have been applied, radiological imaging could have been omitted in 21% of patients with a diagnostic failure rate of 6.1%.

CONCLUSION

By applying clinical probability scoring and D-dimer testing, radiological imaging could be spared in one fifth of patients with suspected recurrent ipsilateral DVT. However, the high failure rate does not support implementation of this strategy in daily practice.

Reasons for Hospitalization of Patients with Acute Pulmonary Embolism Based on the Hestia Decision Rule

Background The Hestia criteria can be used to select pulmonary embolism (PE) patients for outpatient treatment. The subjective Hestia criterion “medical/social reason for admission” allows the treating physician to consider any patient-specific circumstances in the final management decision. It is unknown how often and why this criterion is scored.

Methods This is a patient-level post hoc analysis of the combined Hestia and Vesta studies. The main outcomes were the frequency of all scored Hestia items in hospitalized patients and the explicit reason for scoring the subjective criterion. Hemodynamic parameters and computed tomography-assessed right ventricular (RV)/left ventricular (LV) ratio of those only awarded with the subjective criterion were compared with patients treated at home.

Results From the 1,166 patients screened, data were available for all 600 who were hospitalized. Most were hospitalized to receive oxygen therapy (45%); 227 (38%) were only awarded with the subjective criterion, of whom 51 because of “intermediate to intermediate-high risk PE.” Compared with patients with intermediate risk PE (RV/LV ratio > 1.0) treated at home (179/566, 32%), hospitalized patients with only the subjective criterion had a higher mean RV/LV ratio (mean difference +0.30, 95% confidence interval [CI] 0.19–0.41) and a higher heart rate (+18/min, 95% CI 10–25). No relevant differences were observed for other hemodynamic parameters.

Conclusion The most frequent reason for hospital admission was oxygen therapy. In the decision to award the subjective criterion as sole argument for admission, the severity of the RV overload and resulting hemodynamic response of the patient was taken into account rather than just abnormal RV/LV ratio.

Effectiveness and Safety of Apixaban for Treatment of Venous Thromboembolism in Daily Practice

Introduction  Phase 3 trials have shown comparable efficacy of direct oral anticoagulants (DOACs) and vitamin K antagonists in patients with acute venous thromboembolism (VTE), with less major bleeding events in patients randomized to DOAC treatment. With DOACs being increasingly used in clinical practice, evaluation of the DOACs in daily practice-based conditions is needed to confirm their safety and effectiveness. The aim of this study is to evaluate the effectiveness and safety of apixaban in VTE patients in daily practice. Methods  In this retrospective cohort study, consecutive patients diagnosed with VTE in two Dutch hospitals (Leiden University Medical Center, Leiden and Haga Teaching Hospital, The Hague) were identified based on administrative codes. We assessed recurrent VTE, major bleeding and mortality during a 3-month follow-up period in those treated with apixaban. Results  Of 671 consecutive VTE patients treated with apixaban, 371 presented with acute pulmonary embolism (PE) and 300 patients with deep-vein thrombosis. During 3 months treatment, 2 patients had a recurrent VTE (0.3%; 95% confidence interval [CI]: 0.08-1.1), 12 patients had major bleeding (1.8%; 95% CI: 1.0-3.2), and 11 patients died (1.6%; 95% CI: 0.9-2.9), of which one patient with recurrent PE and one because of a intracerebral bleeding. Conclusion  In this daily practice-based cohort, apixaban yielded a low incidence of recurrent VTE, comparable to the phase 3 AMPLIFY study patients. The incidence of major bleeding was higher than in the AMPLIFY-study patients, reflecting the importance of daily practice evaluation and the fact that results from phase III clinical studies cannot be directly extrapolated toward daily practice.

Current practice patterns of outpatient management of acute pulmonary embolism: A post-hoc analysis of the YEARS study

BACKGROUND

Studies have shown the safety of home treatment of patients with pulmonary embolism (PE) at low risk of adverse events. Management studies focusing on home treatment have suggested that 30% to 55% of acute PE patients could be treated at home, based on the HESTIA criteria, but data from day-to-day clinical practice are largely unavailable.

AIM

To determine current practice patterns of home treatment of acute PE in the Netherlands.

METHOD

We performed a post-hoc analysis of the YEARS study. The main outcomes were the proportion of patients who were discharged <24 h and reasons for admission if treated in hospital. Further, we compared the 3-month incidence of PE-related unscheduled readmissions between patients treated at home and in hospital.

RESULTS

Of the 404 outpatients with PE included in this post-hoc analysis of the YEARS study, 184 (46%) were treated at home. The median duration of admission of the hospitalized patients was 3.0 days. The rate of PE-related readmissions of patients treated at home was 9.7% versus 8.6% for hospitalized patients (crude hazard ratio 1.1 (95% CI 0.57-2.1)). The 3-month incidence of any adverse event was 3.8% in those treated at home (2 recurrent VTE, 3 major bleedings and two deaths) compared to 10% in the hospitalized patients (3 recurrent VTE, 6 major bleedings and fourteen deaths).

CONCLUSIONS

In the YEARS study, 46% of patients with PE were treated at home with low incidence of adverse events. PE-related readmission rates were not different between patients treated at home or in hospital.

Clinical outcomes of postcarotid endarterectomy hypertension

OBJECTIVE

The objective of this study was to determine the clinical relevance of postcarotid endarterectomy hypertension (PEH) by investigating the effect of PEH on hospital length of stay (LOS) and by investigating short-term and long-term complications of PEH. In addition, risk factors for PEH were determined.

METHODS

A single-center retrospective cohort study was performed. Demographic, preoperative, intraoperative, and postoperative outcomes of 192 patients undergoing carotid endarterectomy were evaluated. Outcomes were compared between patients with PEH and patients without PEH. PEH was defined as an acute systolic blood pressure (SBP) rise >170 mm Hg or persistent SBP >150 mm Hg on the ward and leading to the consultation of an internist. The overall survival and event-free survival were compared using a Kaplan-Meier analysis and a Cox regression analysis. A multivariate logistic regression analysis was performed to determine risk factors for PEH.

RESULTS

PEH developed in 44 of 192 patients (25%). Preoperative hypertension (SBP >150 mm Hg) was determined to be a risk factor for PEH (odds ratio, 3.3; 95% confidence interval [CI], 1.6-6.9). Hospital LOS was prolonged in patients with PEH compared with patients without PEH (median LOS of 5 days vs 3 days, respectively; P < .001). No difference in the occurrence of ischemic neurologic events or rebleeding during hospitalization was observed (P = .58 and P = .72, respectively). Cardiovascular and ischemic neurologic events during follow-up did not occur more often in patients with PEH than in patients without PEH (P = .46). There was no difference in mortality between the PEH and non-PEH groups (hazard ratio, 1.6; 95% CI, 0.6-4.3). The same applies to the event-free survival (hazard ratio, 0.77; 95% CI, 0.4-1.7). Combined event-free survival for stroke and myocardial infarction was 92% (95% CI, 87%-97%) at 2 years for patients without PEH and 86% (95% CI, 74%-98%) at 2 years for patients with PEH (P = .25). Event-free survival for mortality was 90% (95% CI, 85%-96%) at 2 years for patients without PEH and 94% (95% CI, 86%-100%) at 2 years for patients with PEH (P = .36).

CONCLUSIONS

Patients with PEH had a significant increase in hospital LOS. However, adverse short-term and long-term events did not occur more often in patients with PEH. High preoperative SBP was identified as a risk factor for PEH; no other demographic and clinical variables were associated with PEH.

Chest X-Ray Not Routinely Indicated Prior to the YEARS Algorithm in the Diagnostic Management of Suspected Pulmonary Embolism

Background  The YEARS algorithm was designed to simplify the diagnostic process of suspected pulmonary embolism (PE) and to reduce the number of required computed tomography pulmonary angiography (CTPA) scans. Chest X-ray (CXR) is often used as initial imaging test in patients suspected for PE. Aim  To determine if CXR results differ between patients with confirmed PE and with PE ruled out, and to investigate whether CXR provides incremental diagnostic value to the YEARS criteria that is used for selecting patients with CTPA indication. Methods  This post-hoc analysis concerned 1,473 consecutive patients with suspected PE who were managed according to YEARS and were subjected to CXR as part of routine care. The prevalence and likelihood ratios of seven main CXR findings for a final diagnosis of PE were calculated. Results  A total of 214 patients were diagnosed with PE at baseline (15%). Abnormal CXR occurred more often in patients with confirmed PE (36%, 77/214) than in patients without PE (26%; 327/1,259), for an odds ratio of 1.60 (95% confidence interval: 1.18-2.18). Only the unexpected finding of a (rib)fracture or pneumothorax, present in as few as six patients (0.4%), significantly lowered the post-test probability of PE to an extent that CTPA could have been avoided. Conclusion  The incremental diagnostic value of CXR to the YEARS algorithm to rule out PE was limited. CXR was more frequently abnormal in patients with PE than in those in whom PE was ruled out. These data do not support to perform CXR routinely in all patients with suspected PE, prior to CTPA imaging.

Pregnancy-Adapted YEARS Algorithm for Diagnosis of Suspected Pulmonary Embolism

BACKGROUND

Pulmonary embolism is one of the leading causes of maternal death in the Western world. Because of the low specificity and sensitivity of the d-dimer test, all pregnant women with suspected pulmonary embolism undergo computed tomographic (CT) pulmonary angiography or ventilation-perfusion scanning, both of which involve radiation exposure to the mother and fetus. Whether a pregnancy-adapted algorithm could be used to safely avoid diagnostic imaging in pregnant women with suspected pulmonary embolism is unknown.

METHODS

In a prospective study involving pregnant women with suspected pulmonary embolism, we assessed three criteria from the YEARS algorithm (clinical signs of deep-vein thrombosis, hemoptysis, and pulmonary embolism as the most likely diagnosis) and measured the d-dimer level. Pulmonary embolism was ruled out if none of the three criteria were met and the d-dimer level was less than 1000 ng per milliliter or if one or more of the three criteria were met and the d-dimer level was less than 500 ng per milliliter. Adaptation of the YEARS algorithm for pregnant women involved compression ultrasonography for women with symptoms of deep-vein thrombosis; if the results were positive (i.e., a clot was present), CT pulmonary angiography was not performed. All patients in whom pulmonary embolism had not been ruled out underwent CT pulmonary angiography. The primary outcome was the incidence of venous thromboembolism at 3 months. The secondary outcome was the proportion of patients in whom CT pulmonary angiography was not indicated to safely rule out pulmonary embolism.

RESULTS

A total of 510 women were screened, of whom 12 (2.4%) were excluded. Pulmonary embolism was diagnosed in 20 patients (4.0%) at baseline. During follow-up, popliteal deep-vein thrombosis was diagnosed in 1 patient (0.21%; 95% confidence interval [CI], 0.04 to 1.2); no patient had pulmonary embolism. CT pulmonary angiography was not indicated, and thus was avoided, in 195 patients (39%; 95% CI, 35 to 44). The efficiency of the algorithm was highest during the first trimester of pregnancy and lowest during the third trimester; CT pulmonary angiography was avoided in 65% of patients who began the study in the first trimester and in 32% who began the study in the third trimester.

CONCLUSIONS

Pulmonary embolism was safely ruled out by the pregnancy-adapted YEARS diagnostic algorithm across all trimesters of pregnancy. CT pulmonary angiography was avoided in 32 to 65% of patients. (Funded by Leiden University Medical Center and 17 other participating hospitals; Artemis Netherlands Trial Register number, NL5726.).

Lower prevalence of subsegmental pulmonary embolism after application of the YEARS diagnostic algorithm

The rate of identified isolated subsegmental pulmonary embolism (ssPE) has doubled with advances in computed tomography pulmonary angiography (CTPA) technology, but its clinical relevance is debated. The YEARS diagnostic algorithm was shown to safely reduce the number of required CTPAs in the diagnostic management of PE. We hypothesized that the higher threshold for performing CTPA in YEARS was associated with a lower prevalence of ssPE compared to the conventional diagnostic algorithm. We compared 2291 consecutive patients with suspected PE managed according to YEARS to 3306 consecutive control patients managed according to the Wells score for the prevalence of isolated ssPE. In the YEARS cohort, 52% were managed without CTPA, 12% had pulmonary embolism (PE) of which 10% were isolated ssPE, and the 3‐month diagnostic failure rate was 0·35%. In the control cohort, 32% were managed without CTPA, 20% had PE of which 16% were isolated ssPE, and the 3‐month failure rate was 0·73%. The isolated ssPE prevalence was significantly lower in YEARS (absolute difference 6·2% (95% confidence interval [CI] 1·4–10), Odds Ratio 0·58 (95% CI 0·37–0·90). In conclusion, YEARS is associated with a lower prevalence of isolated ssPE, due to reduction in CTPAs by the higher D‐dimer threshold. This was however not associated with a higher risk of recurrent VTE during follow‐up.

Novel Anticoagulant Treatment for Pulmonary Embolism with Direct Oral Anticoagulants Phase 3 Trials and Clinical Practice

Anticoagulant therapy is the cornerstone of therapeutic management in acute venous thromboembolism (VTE), consisting of pulmonary embolism and deep vein thrombosis. Direct oral anticoagulants (DOACs) have become the standard of care because of their good safety profile and ease of use in clinical practice. Indeed, phase 3 randomized trials (AMPLIFY, EINSTEIN, RECOVER, and HOKUSAI studies) showed that DOACs provided a similar efficacy and a better safety than conventional treatment with parenteral heparin with overlapping loading dose of vitamin K antagonists in acute VTE therapeutic management. The results of published data from real-world registries confirm the safety and efficacy of DOACs demonstrated in the phase 3 trials.

Sex-specific performance of pre-imaging diagnostic algorithms for pulmonary embolism

Essentials Decision rules for pulmonary embolism are used indiscriminately despite possible sex-differences. Various pre-imaging diagnostic algorithms have been investigated in several prospective studies. When analysed at an individual patient data level the algorithms perform similarly in both sexes. Estrogen use and male sex were associated with a higher prevalence in suspected pulmonary embolism.

SUMMARY

Background In patients suspected of pulmonary embolism (PE), clinical decision rules are combined with D-dimer testing to rule out PE, avoiding the need for imaging in those at low risk. Despite sex differences in several aspects of the disease, including its diagnosis, these algorithms are used indiscriminately in women and men. Objectives To compare the performance, defined as efficiency and failure rate, of three pre-imaging diagnostic algorithms for PE between women and men: the Wells rule with fixed or with age-adjusted D-dimer cut-off, and a recently validated algorithm (YEARS). A secondary aim was to determine the sex-specific prevalence of PE. Methods Individual patient data were obtained from six studies using the Wells rule (fixed D-dimer, n = 5; age adjusted, n = 1) and from one study using the YEARS algorithm. All studies prospectively enrolled consecutive patients with suspected PE. Main outcomes were efficiency (proportion of patients in which the algorithm ruled out PE without imaging) and failure rate (proportion of patients with PE not detected by the algorithm). Outcomes were estimated using (multilevel) logistic regression models. Results The main outcomes showed no sex differences in any of the separate algorithms. With all three, the prevalence of PE was lower in women (OR, 0.66, 0.68 and 0.74). In women, estrogen use, adjusted for age, was associated with lower efficiency and higher prevalence and D-dimer levels. Conclusions The investigated pre-imaging diagnostic algorithms for patients suspected of PE show no sex differences in performance. Male sex and estrogen use are both associated with a higher probability of having the disease.

The YEARS algorithm for suspected pulmonary embolism: shorter visit time and reduced costs at the emergency department

Essentials The YEARS algorithm was designed to simplify the diagnostic workup of suspected pulmonary embolism. We compared emergency ward turnaround time of YEARS and the conventional algorithm. YEARS was associated with a significantly shorter emergency department visit time of ˜60 minutes. Treatment of pulmonary embolism was initiated 53 minutes earlier with the YEARS algorithm SUMMARY: Background Recently, the safety of the YEARS algorithm, designed to simplify the diagnostic work-up of pulmonary embolism (PE), was demonstrated. We hypothesize that by design, YEARS would be associated with a shorter diagnostic emergency department (ED) visit time due to simultaneous assessment of pre-test probability and D-dimer level and reduction in number of CT scans. Aim To investigate whether implementation of the YEARS diagnostic algorithm is associated with a shorter ED visit time compared with the conventional algorithm and to evaluate the associated cost savings. Methods We selected consecutive outpatients with suspected PE from our hospital included in the YEARS study and ADJUST-PE study. Different time-points of the diagnostic process were extracted from the to-the-minute accurate electronic patients' chart system of the ED. Further, the costs of the ED visits were estimated for both algorithms. Results All predefined diagnostic turnaround times were significantly shorter after implementation of YEARS: patients were discharged earlier from the ED; 54 min (95% CI, 37-70) for patients managed without computed tomography pulmonary angiography (CTPA) and 60 min (95% CI, 44-76) for the complete study population. Importantly, patients diagnosed with PE by CTPA received the first dose of anticoagulants 53 min (95% CI, 22-82) faster than those managed according to the conventional algorithm. Total costs were reduced by on average €123 per visit. Conclusion YEARS was shown to be associated with a shorter ED visit time compared with the conventional diagnostic algorithm, leading to faster start of treatment in the case of confirmed PE and savings on ED resources.

No added value of the age-adjusted D-dimer cut-off to the YEARS algorithm in patients with suspected pulmonary embolism

Essentials Imaging is warranted in the majority of patients to confirm or rule out pulmonary embolism (PE). The age-adjusted D-dimer (ADJUST) reduced the number of required imaging tests in patients ≥ 50 years. The YEARS algorithm was designed to improve the efficiency in patients with suspected PE. There was no added value of implementing ADJUST in the YEARS algorithm in our cohort.

SUMMARY

Background The YEARS algorithm was designed to simplify the diagnostic work-up of pulmonary embolism (PE) and to reduce the number of necessary computed tomography pulmonary angiography (CTPA) scans. An alternative strategy to reduce the number of CTPAs is the age-adjusted D-dimer cut-off (ADJUST) in patients aged 50 years or older. We aimed to investigate whether a combination of both diagnostic strategies might save additional CTPAs. Methods The YEARS algorithm consists of three items (clinical signs of deep venous thrombosis, hemoptysis, 'PE most likely diagnosis') with simultaneous D-dimer testing using a pre-test dependent threshold. We performed a post hoc analysis in 3465 patients managed according to YEARS to compare the number of patients managed without CTPA scans and associated diagnostic failures in hypothetical scenarios with different YEARS-ADJUST combinations. Results Following the YEARS algorithm, 1651 patients (48%) were managed without CTPA; PE was diagnosed in 456 (13%) patients at baseline and 18 patients with initial normal testing suffered venous thromboembolism (VTE) during 3-month follow-up (failure rate 0.61%; 95% confidence interval [CI], 0.36-0.96). If ADJUST had been fully integrated in YEARS, 1627 patients (47%) would have been managed without CTPA (absolute decrease of 0.69%; 95% CI -1.7 to 3.0), at cost of four additional missed PE diagnoses at baseline, for a projected 3-month VTE failure rate of 0.75% (95% CI, 0.49-1.13). None of the other studied scenarios showed relevant improvements in efficiency as well, but all led to more missed diagnoses. Conclusion In our cohort, there was no added value of implementing ADJUST in the YEARS algorithm.

Simplified diagnostic management of suspected pulmonary embolism (the YEARS study): a prospective, multicentre, cohort study

BACKGROUND

Validated diagnostic algorithms in patients with suspected pulmonary embolism are often not used correctly or only benefit subgroups of patients, leading to overuse of computed tomography pulmonary angiography (CTPA). The YEARS clinical decision rule that incorporates differential D-dimer cutoff values at presentation, has been developed to be fast, to be compatible with clinical practice, and to reduce the number of CTPA investigations in all age groups. We aimed to prospectively evaluate this novel and simplified diagnostic algorithm for suspected acute pulmonary embolism.

METHODS

We did a prospective, multicentre, cohort study in 12 hospitals in the Netherlands, including consecutive patients with suspected pulmonary embolism between Oct 5, 2013, to July 9, 2015. Patients were managed by simultaneous assessment of the YEARS clinical decision rule, consisting of three items (clinical signs of deep vein thrombosis, haemoptysis, and whether pulmonary embolism is the most likely diagnosis), and D-dimer concentrations. In patients without YEARS items and D-dimer less than 1000 ng/mL, or in patients with one or more YEARS items and D-dimer less than 500 ng/mL, pulmonary embolism was considered excluded. All other patients had CTPA. The primary outcome was the number of independently adjudicated events of venous thromboembolism during 3 months of follow-up after pulmonary embolism was excluded, and the secondary outcome was the number of required CTPA compared with the Wells' diagnostic algorithm. For the primary outcome regarding the safety of the diagnostic strategy, we used a per-protocol approach. For the secondary outcome regarding the efficiency of the diagnostic strategy, we used an intention-to-diagnose approach. This trial is registered with the Netherlands Trial Registry, number NTR4193.

FINDINGS

3616 consecutive patients with clinically suspected pulmonary embolism were screened, of whom 151 (4%) were excluded. The remaining 3465 patients were assessed of whom 456 (13%) were diagnosed with pulmonary embolism at baseline. Of the 2946 patients (85%) in whom pulmonary embolism was ruled out at baseline and remained untreated, 18 patients were diagnosed with symptomatic venous thromboembolism during 3-month follow-up (0·61%, 95% CI 0·36-0·96) of whom six had fatal pulmonary embolism (0·20%, 0·07-0·44). CTPA was not indicated in 1651 (48%) patients with the YEARS algorithm compared with 1174 (34%) patients, if Wells' rule and fixed D-dimer threshold of less than 500 ng/mL would have been applied, a difference of 14% (95% CI 12-16).

INTERPRETATION

In our study pulmonary embolism was safely excluded by the YEARS diagnostic algorithm in patients with suspected pulmonary embolism. The main advantage of the YEARS algorithm in our patients is the absolute 14% decrease of CTPA examinations in all ages and across several relevant subgroups.

FUNDING

This study was supported by unrestricted grants from the participating hospitals.

Incidence of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism: a contemporary view of the published literature

The incidence of chronic thromboembolic pulmonary hypertension (CTEPH) after pulmonary embolism (PE) is relevant for management decisions but is currently unknown.We performed a meta-analysis of studies including consecutive PE patients followed for CTEPH. Study cohorts were predefined as "all comers", "survivors" or "survivors without major comorbidities". CTEPH incidences were calculated using random effects models.We selected 16 studies totalling 4047 PE patients who were mostly followed up for >2-years. In 1186 all comers (two studies), the pooled CTEPH incidence was 0.56% (95% CI 0.1-1.0). In 999 survivors (four studies) CTEPH incidence was 3.2% (95% CI 2.0-4.4). In 1775 survivors without major comorbidities (nine studies), CTEPH incidence was 2.8% (95% CI 1.5-4.1). Both recurrent venous thromboembolism and unprovoked PE were significantly associated with a higher risk of CTEPH, with odds ratios of 3.2 (95% CI 1.7-5.9) and 4.1 (95% CI 2.1-8.2) respectively. The pooled CTEPH incidence in 12 studies that did not use right heart catheterisation as the diagnostic standard was 6.3% (95% CI 4.1-8.4).The 0.56% incidence in the all-comer group probably provides the best reflection of the incidence of CTEPH after PE on the population level. The ∼3% incidences in the survivor categories may be more relevant for daily clinical practice. Studies that assessed CTEPH diagnosis by tests other than right heart catheterisation provide overestimated CTEPH incidences.

Drug Interaction of Fluvoxamine and Fluoxetine with Nevirapine in HIV-1-Infected Individuals

OBJECTIVE

To evaluate the possible pharmacokinetic interactions between nevirapine and fluvoxamine or fluoxetine in patients with HIV-1 infection.

PATIENTS AND METHODS

Patients who were using fluvoxamine or fluoxetine concomitantly were chosen from an unselected cohort (n = 173) of HIV-1-infected individuals using a nevirapine-containing regimen (study group). HIV-1-infected patients using nevirapine without fluvoxamine or fluoxetine and non-HIV-infected individuals who were using fluvoxamine and fluoxetine were included as controls. The influence of fluvoxamine and fluoxetine on the pharmacokinetics of nevirapine was investigated with a previously developed population pharmacokinetic model. Concomitant use of fluvoxamine or fluoxetine was tested independently as covariate for apparent clearance (CL/F) of nevirapine using nonlinear mixed-effect modelling (NONMEM). Furthermore, to explore the influence of nevirapine on the pharmacokinetics of fluvoxamine and fluoxetine, dose-normalised concentrations of fluvoxamine and fluoxetine from the study group were compared with those of the controls.

RESULTS

Of the 173 HIV-1-infected individuals, 14 were using fluoxetine (n = 7) or fluvoxamine (n = 7) simultaneously with nevirapine. In addition, 17 and 29 individuals were identified as controls for the fluoxetine- and fluvoxamine-group, respectively. Concomitant use of fluvoxamine resulted in a significant reduction of 33.7% in CL/F of nevirapine; this reduction in CL/F appeared to be dose-dependent. Concomitant use of fluoxetine had no influence on the pharmacokinetics of nevirapine. Conversely, nevirapine significantly lowered plasma levels of fluoxetine plus norfluoxetine (seproxetine). In contrast, no significant difference was observed in dose-normalised concentrations of fluvoxamine when the controls were compared with the study group.

CONCLUSION

We advise that special attention is paid to HIV-1-infected indivi-duals using a nevirapine-containing regimen and fluvoxamine or fluoxetine con-comitantly, since pharmacokinetic interactions have been observed.

Lipopolysaccharide levels are elevated in dengue virus infected patients and correlate with disease severity

BACKGROUND

Although in the majority of cases dengue virus (DENV) infection results in a self-limiting febrile disease, it can cause severe plasma leakage in a minority of patients. The appearance of plasma leakage indicates an increased permeability of the vascular wall. In this study we investigated if DENV infection can lead to leakage of lipopolysaccharide (LPS) from the intestine into the blood of the patient, indicative of an increased permeability of the intestinal mucosal barrier.

OBJECTIVES

The aim of this study was to investigate if LPS levels were elevated in DENV infected patients and if these levels correlated with disease severity.

STUDY DESIGN

LPS levels in the blood of DENV infected children were determined using the Limulus Amebocyte Lysate assay. To determine disease severity we used the 1997-WHO criteria, the expert physician's judgement and a score that focused on plasma leakage in particular. Furthermore, the modulatory factors LPS binding protein (LBP) and sCD14, as well as the immune activation marker neopterin were determined.

RESULTS

We showed significantly elevated LPS levels in plasma of DENV infected children compared to healthy controls. The plasma leakage severity score had the strongest correlation with levels of LPS. LBP, sCD14 and neopterin were elevated compared to healthy controls.

CONCLUSION

In this study we show evidence of elevated LPS levels during DENV infection. Moreover, a correlation between LPS levels and disease severity was found, especially when disease severity was determined in terms of plasma leakage.

Plasma levels of inter-alpha inhibitor proteins in children with acute Dengue virus infection

Background

Inter-α inhibitor proteins (IaIp) belong to a family of protease inhibitors that are involved in the haemostatic and the vascular system. Dengue viruses (DENV) infections are characterized by coagulopathy and increased vascular permeability. In this study we measured the concentration of IaIp during DENV infections and evaluated its potential as a biomarker.

Methods and Findings

Concentrations of IaIp were measured in patients with acute DENV infections using a quantitative, competitive enzyme linked immunoassay. Concentrations of IaIp measured in pediatric patients suffering from severe DENV infections were significantly lower than in healthy controls.

Conclusions

This is the first report to demonstrate changes in concentration of IaIp during viral infections. The data also highlight the potential of IaIp as a biological marker for severity of DENV infections.

What role do coagulation disorders play in the pathogenesis of leptospirosis?

Leptospirosis is a zoonosis of worldwide distribution, spread by the urine of infected animals. It is a major public health problem, especially in developing countries, where circumstances for transmission are most favourable. The clinical picture varies from mild disease to a severe illness with haemostatic derangements and multiorgan failure eventually leading to death. Although the haemorrhagic complications of severe disease are serious, the pathophysiology is scarcely elucidated. The complex mechanisms involved in inflammation-induced coagulation activation are extensively studied in various infectious diseases, i.e. Gram-negative sepsis. Tissue factor-mediated coagulation activation, impairment of anticoagulant and fibrinolytic pathways in close concert with the cytokine network are thought to be important. But for human leptospirosis, data are limited. Because of the growing interest in this field, the impact of leptospirosis, and the availability of new therapeutic strategies, we reviewed the evidence regarding the role of coagulation in leptospirosis and provide suggestions for future research.

Population pharmacokinetics of lopinavir in combination with ritonavir in HIV-1-infected patients

AIMS

To develop a population pharmacokinetic model for lopinavir in combination with ritonavir, in which the interaction between both drugs was characterized, and in which relationships between patient characteristics and pharmacokinetics were identified.

METHODS

The pharmacokinetics of lopinavir in combination with ritonavir were described using NONMEM (version V, level 1.1). First, ritonavir data were fitted to a previously developed model to obtain individual Bayesian estimates of pharmacokinetic parameters. Hereafter, an integrated model for the description of the pharmacokinetics of lopinavir with ritonavir was designed.

RESULTS

From 122 outpatients 748 lopinavir and 748 ritonavir plasma concentrations were available for analysis. The interaction between the drugs was described by a time-independent inverse relationship between the exposure to ritonavir over a dosing-interval and the apparent clearance (CL/F) of lopinavir. The model parameters volume of distribution and absorption rate constant were 61.6 l (95% prediction interval (PI) 22.4, 83.7) and 0.564 h(-1) (95% PI 0.208, 0.947), respectively. The model yielded a theoretical value for the CL/F of lopinavir without ritonavir of 14.8 l h(-1) (95%PI 12.1, 20.1), which translates to a value of 5.73 l h(-1) in the presence of ritonavir. The only factor with significant effect on the pharmacokinetics was concurrent use of non-nucleoside reverse transcriptase inhibitors (NNRTI), which increased the CL/F of lopinavir by 39% (P < 0.001).

CONCLUSIONS

We have developed a model that has defined a time-independent inverse relationship between the exposure to ritonavir and the CL/F of lopinavir, and provided an adequate description of the pharmacokinetic parameters for the latter. Concomitant use of the NNRTIs efavirenz and nevirapine increased the CL/F of lopinavir.

No pharmacokinetic drug-drug interaction between nevirapine and paclitaxel

We have investigated the pharmacokinetics of nevirapine and paclitaxel in a patient who used both drugs concomitantly, as there are strong theoretical indications for a potential pharmacokinetic drug-drug interaction. Plasma concentrations of nevirapine (dose: 200 mg twice daily orally) and paclitaxel (dose: 100 mg/m(2) 3-h i.v. infusion) were determined in a HIV-1-infected patient with Kaposi's sarcoma. Since both drugs are metabolized via the same cytochrome P450 isoenzymes, investigation of a drug-drug interaction was considered important. We found that the plasma concentrations of nevirapine given together with paclitaxel were similar to those given without paclitaxel. The exposures to paclitaxel (AUC(0-infinity) = 3787 h.ng/ml) and its hydroxy metabolites when co-administered with nevirapine were comparable to the mean exposure to paclitaxel and its metabolites from eight historical controls (AUC(0-infinity) = 3614 h.ng/ml) treated with the same dose. No pharmacokinetic drug-drug interaction between nevirapine and paclitaxel could be demonstrated in our HIV-1-infected patient.

Increased PAI-1 plasma levels and risk of death from dengue: no association with the 4G/5G promoter polymorphism

Background

Dengue virus infected patients have high plasminogen activator inhibitor type I (PAI-1) plasma concentrations. Whether the insertion/deletion (4G/5G) polymorphism in the promotor region of the PAI-1 gene is associated with increased PAI-1 plasma concentrations and with death from dengue is unknown. We, therefore, investigated the relationship between the 4G/5G polymorphism and PAI-1 plasma concentrations in dengue patients and risk of death from dengue.

Methods

A total of 194 patients admitted to the Dr. Kariadi Hospital in Semarang, Indonesia, with clinical suspected severe dengue virus infection were enrolled. Blood samples were obtained on day of admission, days 1, 2 and 7 after admission and at a 1-month follow-up visit. Plasma concentrations of PAI-1 were measured using a sandwich ELISA kit. The PAI-1 4G/5G polymorphism was typed by allele-specific PCR analysis.

Results

Concentrations of PAI-1 on admission and peak values of PAI-1 during admission were higher than the values measured in healthy controls. Survival was significantly worse in patients with PAI-1 concentrations in the highest tertile (at admission: OR 4.7 [95% CI 0.9–23.8], peak value during admission: OR 6.3 [95%CI 1.3–30.8]). No association was found between the PAI-1 4G/5G polymorphism, and PAI-1 plasma concentrations, dengue disease severity and mortality from dengue.

Conclusion

These data suggest that the 4G/5G polymorphism has no significant influence on PAI-1 concentrations in dengue virus infected patients and is not associated with the risk of death from dengue. Other factors contributing to the variability of PAI-1 plasma concentrations in patients with dengue need to be explored.

Elevated plasma levels of the long pentraxin, pentraxin 3, in severe dengue virus infections

C-reactive protein is one of the most widely used indicators of the response of acute-phase proteins. The measurement of C-reactive protein in dengue, however, is clinically not useful, because of marginally elevated levels and absent association with disease severity. The prototypic long pentraxin, pentraxin 3, is an acute phase protein that is structurally related but distinct from C-reactive protein which has proven to correlate with the severity of bacterial infection in critically ill patients. The potential involvement of pentraxin 3 in dengue and its aptitude to predict more severe disease or poor clinical outcome has not been studied previously. We therefore measured pentraxin 3 plasma levels in 44 dengue virus infected patients. Pentraxin 3 levels were strikingly higher when compared to C-reactive protein levels, with highest pentraxin 3 values observed in the first 7 days after the onset of symptoms. Median pentraxin 3 levels at admission and peak levels during follow up were higher in patients suffering from dengue shock syndrome (at admission: 119.3 ng/ml [interquartile range 61.8--188.7], peak values during follow up: 147.9 ng/ml [interquartile range 85.7--204.3]) compared to levels found in patients with dengue fever and dengue hemorrhagic fever (at admission: 59.0 ng/ml [interquartile range 28.6--100.3], P=0.040; peak values during follow up: 80.8 ng/ml [interquartile range 36.1--168.1], P=0.020). Our results indicate that pentraxin 3 seems to be a marker of infection better than C-reactive protein in dengue. The role of pentraxin 3 in the pathogenesis of dengue and its potential as an early prognostic indicator of disease severity needs further assessment.

[Acute respiratory tract infections and acute coronary syndromes]

Epidemiological research indicates a correlation between respiratory-tract infections and acute cardiovascular events. Chronic infections have been linked to the development of atherosclerosis. As a result of chronic infections a prolonged and elevated inflammatory activity arises. Inflammation and the associated vessel-wall damage play an important role in the pathophysiology of atherosclerosis. Acute infections have been linked to a transient increased risk of unstable angina pectoris and an acute myocardial infarct. The consequence of acute infections is a systemic inflammatory response which results in changes in the atherosclerotic plaque, thrombotic activation and a prothrombotic condition. The inflammatory response and prothrombotic condition reinforce each other. This can result in coagulation on ruptured atherosclerotic plaques and erosions in the vessel wall, which can give rise to the sudden constriction or blockage of coronary arteries.

Development and validation of a population pharmacokinetic model for ritonavir used as a booster or as an antiviral agent in HIV-1-infected patients

AIMS

The aim of this study was to develop and validate a population pharmacokinetic model of ritonavir, used as an antiviral agent or as a booster, in a large patient population and to identify factors influencing its pharmacokinetics.

METHODS

Ambulatory HIV-1-infected patients from the outpatient clinic of the Slotervaart Hospital, Amsterdam, the Netherlands, who were being treated with a ritonavir-containing regimen were included. During regular visits, blood samples were collected for the determination of ritonavir plasma concentrations and several clinical chemistry parameters. Furthermore, complete pharmacokinetic curves were available in some patients. Single and multiple compartment models with zero-order and first-order absorption, with and without absorption lag-time, with linear and nonlinear elimination were tested, using nonlinear mixed effect modelling (NONMEM). Pharmacokinetic parameters and interindividual, interoccasion and residual variability were estimated. In addition, the influence of several factors (e.g. patient characteristics, comedication) on the pharmacokinetics of ritonavir was explored.

RESULTS

From 186 patients 505 ritonavir plasma concentrations at a single time-point and 55 full pharmacokinetic profiles were available, resulting in a database of 1228 plasma ritonavir concentrations. In total 62% of the patients used ritonavir as a booster of their protease inhibitor containing antiretroviral regimen. First order absorption in combination with one-compartment disposition best described the pharmacokinetics of ritonavir. Clearance, volume of distribution and absorption rate constant were 10.5 l h(-1) (95% prediction interval (95% PI) 9.38-11.7), 96.6 l (95% PI 67.2-121) and 0.871 h(-1) (95% PI 0.429-1.47), respectively, with 38.3%, 80.0% and 169% interindividual variability, respectively. The interoccasion variability in the apparent bioavailability was 59.1%. The concomitant use of lopinavir resulted in a 2.7-fold increase in the clearance of ritonavir (P value < 0.001). No patients characteristics influenced the pharmacokinetics of ritonavir.

CONCLUSIONS

The pharmacokinetic parameters of ritonavir were adequately described by our population pharmacokinetic model. Concomitant use of the protease inhibitor lopinavir strongly influenced the pharmacokinetics of ritonavir. The model has been validated and can be used for further investigation of the interaction between ritonavir and other protease inhibitors.

The plasma and intracellular steady-state pharmacokinetics of lopinavir/ritonavir in HIV-1-infected patients

Therapeutic drug monitoring of protease inhibitors (PIs) is usually performed on plasma samples although their antiretroviral effect takes place inside cells. Little is known, however, about the intracellular accumulation and related plasma pharmacokinetics of PIs such as lopinavir/ritonavir (LPV/RTV). Therefore, we studied the plasma and intracellular (cell-associated) steady-state pharmacokinetics of this PI combination in a dosage of 400/100 mg twice daily in a non-randomized cohort of HIV-1-infected individuals. Plasma (0-12 h) and peripheral blood mononuclear cell (PBMC; 0-8 h) samples were drawn during a 12-h dosing interval in 11 subjects. The plasma concentrations versus time curves of LPV and RTV were characterized by an irregular absorption phase showing double-peaks (Cmax) in most subjects and single-peaks in the remaining patients between 1 and 3 h after drug intake. Pre-dose concentrations of both agents in plasma were significantly higher than the concentrations at the end of the dosing interval indicating the presence of a circadian rhythm in their pharmacokinetics. The course of the intracellular concentrations versus time curves appeared to be similar to the plasma concentration curves, with the highest intracellular concentration measured 3 h after drug intake. The intracellular RTV concentrations were higher than reported in vitro EC50 values and might therefore contribute to the antiretroviral effect of LPV/RTV. The median intracellular-to-plasma concentration ratios (interquartile range) were 1.18 (0.74-2.06) and 4.59 (3.20-7.70) for LPV and RTV, respectively. In conclusion, both LPV and RTV accumulate to potential therapeutic concentrations in PBMCs. Irregular absorption and circadian plasma clearance patterns were observed for the PI combination LPV/RTV.

Non-invasive diagnostic work-up of patients with clinically suspected pulmonary embolism; results of a management study

BACKGROUND

Clinicians often deviate from the recommended algorithm for the diagnosis of pulmonary embolism consisting of ventilation-perfusion scintigraphy and pulmonary angiography.

OBJECTIVES

To assess the safety and feasibility of a diagnostic algorithm which reduces the need for lung scintigraphy and avoids the use of angiography.

PATIENTS AND METHODS

Consecutive patients with a clinical suspicion of pulmonary embolism were prospectively investigated according to an algorithm in which the diagnosis of pulmonary embolism was excluded after a low clinical probability estimate and a normal d-dimer test result, a normal perfusion scintigraphy result, or a non-high probability scintigraphy result in combination with normal serial ultrasonography of the legs. In these patients anticoagulant treatment was withheld and they were followed up for 3 months to record possible thromboembolic events. During the study period, 923 consecutive patients were seen, of whom 292 were excluded because of predefined criteria.

RESULTS

Of the 631 included patients, the diagnosis was refuted on the basis of a low clinical probability estimate and a normal d-dimer test result (95 patients), normal perfusion scintigraphy (161 patients) and non-high probability lung scintigraphy followed by normal serial ultrasonography (210 patients). Of these 466 patients, venous thromboembolic complications during follow-up occurred in six (complication rate 1.3%, 95% confidence interval 0.5, 2.8). The diagnostic protocol was completed in 92% of all included patients.

CONCLUSION

The diagnosis of pulmonary embolism can be safely ruled out by a non-invasive algorithm consisting of d-dimer testing combined with a clinical probability estimate, lung scintigraphy, or serial ultrasonography of the legs (in case of non-diagnostic lung scintigraphy).

Dengue: an arthropod-borne disease of global importance

Dengue viruses cause a variable spectrum of disease that ranges from an undifferentiated fever to dengue fever to the potentially fatal dengue shock syndrome. Due to the increased incidence and geographical distribution of dengue in the last 50 years, dengue is becoming increasingly recognised as one of the world's major infectious diseases. This article will review clinical and diagnostic aspects of dengue virus infections. It also presents our current knowledge of the pathophysiology of severe dengue and addresses the importance of dengue virus infections in those travelling to parts of the world where dengue is endemic.

Evaluation of clinical pharmacist interventions on drug interactions in outpatient pharmaceutical HIV-care

OBJECTIVE

To evaluate the usefulness of intervention in drug interactions of antiretroviral drugs with coadministered agents by a clinical pharmacist in outpatient HIV-treatment.

METHODS

The study design included two intervention arms (A and B), which were both preceded by a control observation period. In arm A, a complete list of the currently used drugs, extracted from pharmacy records was provided to the treating physician. In arm B the same list was provided but with a notification when a drug interaction was present and an advice how to handle this. The infectious disease specialist obtained the information before the patient's visit to the outpatient clinic (time point 0). Three months prior (time point -3) and 3 months after (time point +3) the intervention, pharmacy records were also screened for drug interactions. The number of drug interactions (total and per patient) was determined at the three different time points (-3, 0, +3). In addition, drug interactions encountered at time points -3 and 0 were checked for their presence at time points 0 and +3, respectively, for both intervention arms.

RESULTS

Arms A and B included 115 and 105 patients, respectively. Patient characteristics of both intervention arms were similar at time point 0. The number of interactions and the number of patients with interactions were similar in both intervention arms at time point 0. There were 42 and 40 potential drug interactions in 30 and 24 patients in arms A and B, respectively. The reduction in the number of interactions per patient over time and after intervention was small but significant, and was equal in both intervention arms. The advice of the clinical pharmacist had thus no additional value.

CONCLUSION

Both interventions were effective in reducing the number of drug interactions per patient. The advice of a clinical pharmacist was, however, redundant in the studied setting.

Infections and endothelial cells

Systemic infection by various pathogens interacts with the endothelium and may result in altered coagulation, vasculitis and atherosclerosis. Endothelium plays a role in the initiation and regulation of both coagulation and fibrinolysis. Exposure of endothelial cells may lead to rapid activation of coagulation via tissue factor (TF) expression and the loss of anticoagulant properties by impairment of antithrombin III, TF pathway inhibitor (TFPI) and the protein C system. Endothelial-derived plasminogen activator inhibitor (PAI) is essential for the regulation of fibrinolysis and impaired endothelial function leads to imbalance in fibrinolysis, resulting in a procoagulant state. The interaction between inflammation and coagulation, soluble adhesion molecules and circulation endothelial cells is important in the pathogenesis of an unbalanced haemostatic system. Rather than being a unidirectional relationship, the interaction between inflammation and coagulation appears to be significant. In the crosstalk, the endothelium is playing a pivotal role.

Treating viral hemorrhagic fever

Viral hemorrhagic fevers are illnesses associated with a number of geographically restricted, mostly tropical areas. Over recent decades a number of new hemorrhagic fever viruses have emerged. Advances in our understanding of the pathophysiology of these diseases have improved our initial supportive management and led to the recognition of several potentially useful antiviral agents. This review focuses on these hemorrhagic fever viruses and specifically addresses therapeutic aspects and recent progress that has been made in the treatment of these viral pathogens.

Case series of acute hepatitis in a non-selected group of HIV-infected patients on nevirapine-containing antiretroviral treatment

OBJECTIVE

To evaluate the characteristics of patients who developed acute clinical hepatitis in an unselected outpatient population.

METHODS

Patients who started a nevirapine-containing regimen in the period January 1999-February 2001 and presented with clinical symptoms in accordance with increased transaminase values within 12 weeks of initiation of nevirapine were considered possible cases of clinical hepatotoxicity. Patient characteristics, co-medicated drugs, HIV-1 RNA levels and clinical chemistry parameters were collected from outpatient medical records and clinical medical records.

RESULTS

At the defined period, 306 patients started a nevirapine-containing regimen, of whom eight developed an acute hepatitis (2.6%) in a median of 24 days [interquartile range (IQR) 20-25 days]. Transaminases peaked at 28 days (IQR, 27-32 days). Injury pattern was in general mixed-hepatocellular. Withdrawal of the antiretroviral agent led to rapid restoration of transaminase levels and resolution of clinical symptoms. The reason for developing this hepatic reaction was not clear in every case as no specific risk factor(s) covering all patients in this case series could be identified.

CONCLUSIONS

It is very important to monitor closely transaminase levels of all patients starting a nevirapine-containing regimen, including patients with no specific characteristics that put them at risk. The rapid onset of the clinical symptoms pleads for transaminase monitoring at a very early stage (i.e., within 2 weeks of initiation) of the nevirapine-containing regimen.

Incidence and risk factors for nevirapine-associated rash

OBJECTIVE

To determine the incidence of rash in HIV-1 infected individuals starting a nevirapine-containing regimen in an unselected outpatient clinic population. Possible risk factors including plasma concentrations of nevirapine were evaluated for their relationship with the occurrence of a rash.

METHODS

The occurrence of rash was extracted from the outpatient medical records or based on a prescription of the antihistaminic cetirizine as documented by the community pharmacy within the first 90 days of nevirapine use. During regular visits to the clinic blood samples were collected for the determination of nevirapine plasma concentrations. Possible risk factors such as demographics, immunology, virology, clinical chemistry and antiretroviral pretreatment were collected at baseline for each patient. In addition, concomitantly used drugs during the nevirapine-based regimen were recorded. The association between these factors and the occurrence of rash was studied. Primary outcome was the onset of rash within the first 90 days after initiation of a nevirapine-containing regimen.

RESULTS

Data from 216 HIV-1-infected patients were used in this study. Thirty-eight patients (17.6%) developed a rash of some grade that led to discontinuation of nevirapine in seven patients (3.2% of the included patients). The median time to occurrence of rash was 26 days (interquartile range 17-46 days). The multivariate analysis showed that patients pretreated with antiretroviral drugs less than 12 months before the initiation of a nevirapine-containing regimen had a more than 2.5-fold increased risk of developing rash. Furthermore, nevirapine plasma concentrations were also significantly related to the occurrence of rash. A more than twofold increased risk for developing rash was observed for patients with nevirapine plasma concentrations above 5.3 mg/l.

CONCLUSIONS

This is the first study demonstrating that patients with antiretroviral pretreatment less than 12 months and with nevirapine plasma concentrations above 5.3 mg/l during the first 90 days of treatment are at a higher risk for the development of rash. It is therefore advised to monitor this group of patients carefully when initiating nevirapine-containing therapy.

Subtherapeutic antiretroviral plasma concentrations in routine clinical outpatient HIV care

The objective of this study was to evaluate plasma concentrations of nonnucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs) within several dosing schemes in a cohort of HIV-infected patients in routine clinical practice and to find possible explanations for subtherapeutic plasma concentrations. Patients were included if a PI or NNRTI was part of their antiretroviral regimen, at least one plasma concentration was obtained, and a complete medication overview from community pharmacy records was available. The study period was from January 1998 to September 2001. Each plasma concentration was related to median plasma concentrations of a pharmacokinetic reference curve, yielding a concentration ratio (CR). A cutoff CR was defined for each antiretroviral drug per specific regimen, discriminating between >or=therapeutic and subtherapeutic concentrations. For the patients with subtherapeutic concentrations, it was sorted out whether drug interactions, adverse events and self-reported symptoms, or nonadherence could be the cause of the lower than expected plasma concentration. Ninety-seven HIV-infected patients fulfilled the criteria. During the defined period, 1145 plasma concentrations were available (median, 11; interquartile range, 8-14). Three hundred fourteen (27.4%) plasma concentrations were classified subtherapeutic. Drug interactions (2; 0.6%), adverse events and self-reported symptoms (67; 21.3%), and nonadherence (14; 4.5%) could only partly explain the subtherapeutic drug levels. Consequently, a large number of the subtherapeutic plasma concentrations (73.6%) remained inexplicable. A high number of subtherapeutic plasma concentrations were observed. No clear causes were found; thus, corrective measures will be difficult to employ. Therefore, therapeutic drug monitoring (TDM) must maintain its crucial place in routine clinical care to be able to identify patients who need extra attention so that therapeutic plasma concentrations are achieved.

Is clinical outcome of dengue-virus infections influenced by coagulation and fibrinolysis? A critical review of the evidence

Despite efforts to elucidate the pathogenesis of dengue fever, the progression into severe disease remains poorly understood. In-vitro findings suggest that coagulopathy and disturbances in fibrinolysis have a pivotal role in the pathophysiology. If disturbances in these processes are predictive of clinical outcome in this disease, there could be important consequences for both diagnosis and treatment. We have critically reviewed publications on this topic to assess whether there is an association between activation of coagulation and fibrinolysis and clinical outcome of dengue-virus infections. In general, the selected studies showed activation of both the coagulation and fibrinolytic systems in this infection. The activation was more pronounced in severe infections and in cases with a poor clinical outcome. However, the findings were not consistent, and owing to a lack of detailed information on characteristics of patients, disease, and study design, we could not ascertain whether inconsistencies were caused by differences in these characteristics, selection bias, or confounding factors. We conclude that an association between activation of coagulation and fibrinolysis and clinical outcome of dengue-virus infections is conceivable but has been inadequately assessed and that methodologically sound studies, complemented with complete and reliable reporting, are needed to show whether there is a true association.