British Thoracic Society Standards of Care Committee Pulmonary Embolism Guideline Development Group. British Thoracic Society guidelines for the management of suspected acute pulmonary embolism

Treating pulmonary embolism at home?

For select patients, acute PE can be managed safely and effectively without hospitalization.

Therapy and outcomes in massive pulmonary embolism from the Emergency Medicine Pulmonary Embolism in the Real World Registry

STUDY AIM

Clinical guidelines recommend fibrinolysis or embolectomy for acute massive pulmonary embolism (PE) (MPE). However, actual therapy and outcomes of emergency department (ED) patients with MPE have not previously been reported. We characterize the current management of ED patients with MPE in a US registry.

METHODS

A prospective, observational, multicenter registry of ED patients with confirmed PE was conducted from 2006 to 2008. Massive PE was defined as PE with an initial systolic blood pressure less than 90 mm Hg. We compared inpatient and 30-day mortality, bleeding complications, and recurrent venous thromboembolism.

RESULTS

Of 1875 patients enrolled, 58 (3.1%) had MPE. There was no difference in frequency of parenteral anticoagulation (98.3% [95% confidence interval {CI}, 90.5-101.6] vs 98.5% [95% CI, 97.9-99.1], P = .902) between patients with and without MPE. Fibrinolytic therapy and embolectomy were infrequently used but were used more in patients with MPE than in patients without MPE (12.1% [95% CI, 3.7-20.5] vs 2.4% [95% CI, 1.7-3.1], P < .001, and 3.4% [95% CI, 0.0-8.1] vs 0.7% [95% CI, 0.3-1.1], P = .022, respectively). Comparison of outcomes revealed higher all-cause inpatient mortality (13.8% [95% CI, 4.9-22.7] vs 3.0% [95% CI, 2.2-3.8], P < .001), higher risk of inpatient bleeding complications (10.3% [95% CI, 2.5-18.1] vs 3.5% [95% CI, 2.7-4.3], P = .007), and a higher 30-day mortality (14.0% [95% CI, 4.4-23.6] vs 1.8% [95% CI, 1.2-2.4], P < .001) for patients with MPE.

CONCLUSIONS

In a contemporary registry of ED patients, MPE mortality was 4-fold higher than patients without MPE, yet only 12% of the MPE cohort received fibrinolytic therapy. Variability exists between the treatment of MPE and current recommendations.

Pulmonary embolism

Pulmonary embolism (PE) remains one of the most challenging medical diseases in the emergency department. PE is a potentially life threatening diagnosis that is seen in patients with chest pain and/or dyspnea but can span the clinical spectrum of medical presentations. In addition, it does not have any particular clinical feature, laboratory test, or diagnostic modality that can independently and confidently exclude its possibility. This article offers a review of PE in the emergency department. It emphasizes the appropriate determination of pretest probability, the approach to diagnosis and management, and special considerations related to pregnancy and radiation exposure.

Delay in diagnosis of pulmonary thromboembolism in emergency department: is it still a problem?

BACKGROUND AND AIM

Pulmonary embolism (PE) is a common and serious disease that can result in death unless emergent diagnosis is made and treatment is initiated. In this study, we aimed to identify whether there is still a delay in the diagnosis of PE and to identify the time to delay in diagnosis and factors leading to this delay.

METHODS

This is a prospective observational cohort study performed in an emergency department (ED) of a tertiary care university hospital between September 2008 and September 2010. The rate and cause of delay in diagnosis were analyzed among patients with PE. The "delay" was defined as diagnosing after first 24 hours of symptom onset.

RESULTS

Among the 53 patients who were diagnosed with PE, a delay in diagnosis was present in 49 (93%) of them. Total delay time was 6.8 ± 7.7 days. In 33 (62%) patients, there was a delay of 4.6 ± 6.5 days due to patient-related factors. Delay in diagnosis after admission to hospital was 2.2 ± 2.9 days in 40 (75%) patients. In multivariate regression analysis, being female and having chest pain and cough were identified as significant factors causing patient-related delay. Unilateral leg edema, recent operation, and previous venous thromboembolism (VTE) history were the significant factors causing PE diagnosis without a delay. On the other hand, systemic hypertension as comorbidity was the only factor leading to physician-related delay.

CONCLUSION

The delay in diagnosis of PE in EDs still remains as an important problem. While being female and having chest pain and cough are significantly and independently associated with patient delay in diagnosis, the unilateral leg edema, recent operation, and previous VTE history cause physicians to diagnose on time. On the other hand, having hypertension as comorbidity may lead to physician delay. In order to prevent the delay in diagnosis, hospital-associated factors must be elucidated totally and more interventions must be made to increase public and professional awareness of the disease.

Derivation and validation of a multivariate model to predict mortality from pulmonary embolism with cancer: The POMPE-C tool

BACKGROUND

Clinical guidelines recommend risk stratification of patients with acute pulmonary embolism (PE). Active cancer increases risk of PE and worsens prognosis, but also causes incidental PE that may be discovered during cancer staging. No quantitative decision instrument has been derived specifically for patients with active cancer and PE.

METHODS

Classification and regression technique was used to reduce 25 variables prospectively collected from 408 patients with AC and PE. Selected variables were transformed into a logistic regression model, termed POMPE-C, and compared with the pulmonary embolism severity index (PESI) score to predict the outcome variable of death within 30 days. Validation was performed in an independent sample of 182 patients with active cancer and PE.

RESULTS

POMPE-C included eight predictors: body mass, heart rate >100, respiratory rate, SaO2%, respiratory distress, altered mental status, do not resuscitate status, and unilateral limb swelling. In the derivation set, the area under the ROC curve for POMPE-C was 0.84 (95% CI: 0.82-0.87), significantly greater than PESI (0.68, 0.60-0.76). In the validation sample, POMPE-C had an AUC of 0.86 (0.78-0.93). No patient with POMPE-C estimate ≤ 5% died within 30 days (0/50, 0-7%), whereas 10/13 (77%, 46-95%) with POMPE-C estimate >50% died within 30 days.

CONCLUSION

In patients with active cancer and PE, POMPE-C demonstrated good prognostic accuracy for 30 day mortality and better performance than PESI. If validated in a large sample, POMPE-C may provide a quantitative basis to decide treatment options for PE discovered during cancer staging and with advanced cancer.

LR-PED rule: low risk pulmonary embolism decision rule - a new decision score for low risk pulmonary embolism

INTRODUCTION

When accurately diagnosed, non-massive Pulmonary embolism (PE) has a low mortality rate. However, some patients initially considered to be low risk show progressive deterioration. This research aims at developing a preliminary score that allows detection of low risk patients potentially eligible for outpatient treatment.

MATERIALS AND METHODS

Retrospective cohort study involving 142 asymptomatic/mildly symptomatic and hemodynamically stable patients with PE and no clinical/echocardiographic signs of right ventricular dysfunction. Collected data: risk factors, analytic/gasometric parameters, admission echocardiogram, thoracic CT angiography. Patients followed for 6months. Primary endpoint: 1-month all-cause mortality. Secondary endpoints: Intrahospital and 6-month all-cause mortality. A score designed for identification of very low risk patients eligible for outpatient treatment was developed and its prognostic accuracy compared to that of the Geneva and simplified PESI models.

RESULTS

A score for predicting 1-month mortality (Low Risk Pulmonary Embolism Decision [LR-PED] rule) was obtained using Binary Logistic Regression, including: age, atrial fibrillation at admission, previous heart failure, admission heart rate, creatinine, glycaemia, troponin I and C-reactive protein at admission. ROC curve analysis assessed its overall accuracy for predicting 1-month, intrahospital and 6-month mortality (AUC=0.756, 0.763 and 0.854, respectively). Compared to Geneva and simplified PESI, the LR-PED rule showed higher sensitivity and negative predictive value for the detection of the lowest risk patients. The net reclassification improvement index revealed significant successful upward risk reclassification by the LR-PED model of patients reaching primary or secondary outcomes.

CONCLUSIONS

LR-PED rule seems more attractive than Geneva or simplified PESI in its ability to identify patients at very low mortality risk who would be potentially eligible for outpatient treatment. Prospective validation of this score in larger cohorts is mandatory before its potential implementation.

Performance of the Pulmonary Embolism Rule-out Criteria (the PERC rule) combined with low clinical probability in high prevalence population

INTRODUCTION

PERC rule was created to rule out pulmonary embolism (PE) without further exams, with residual PE risk<2%. Its safety is currently not confirmed in high PE prevalence populations even when combined with low clinical probability assessed by revised Geneva score (RGS). As PERC rule and RGS are 2 similar explicit rules with many redundant criteria, we hypothesized that the combination of PERC rule with gestalt clinical probability could resolve this limitation.

METHODS

We collected prospectively documented clinical gestalt assessments and retrospectively calculated PERC rules and RGS from a prospective study of PE suspected patients. We analyzed performance of combinations of negative PERC with low clinical probability assessed by both methods in high overall PE prevalence population.

RESULTS

Among the final study population (n = 959), the overall PE prevalence was 29.8%. Seventy-four patients (7.7%) were classified as PERC negative and among them, 4 patients (5.4%) had final diagnosis of PE. When negative PERC was combined with low pretest probability assessed by RGS or gestalt assessment, PE prevalence was respectively 6.2% and 0%. This last combination reaches threshold target of 2% and unnecessary exams could easily have been avoided in this subgroup (6%). However, it confidence interval was still wide (0%; CI 0-5).

CONCLUSIONS

PERC rule combined with low gestalt probability seems to identify a group of patients for whom PE could easily be ruled out without additional test. A larger study is needed to confirm this result and to ensure safety.

Study of compliance with a clinical pathway for suspected pulmonary embolism

BACKGROUND/AIMS

Clinical pathways to guide the investigation of suspected pulmonary embolism have been increasingly adopted by emergency departments worldwide. This study evaluated the compliance with a clinical pathway that combines risk assessment (Wells score) with d-dimer, ventilation-perfusion scanning or computed tomographic pulmonary angiography (CTPA). The aims of this study were to identify factors that contribute to compliance and to assess patient outcomes and resource utilization.

METHODS

Repeated retrospective chart reviews of 239 patients who underwent investigation for pulmonary embolism through our emergency department extracted patient demographics, pathway parameters and patient outcomes. A phone interview at 3-month follow up was carried out.

RESULTS

Incidence of pulmonary embolism was 8.4% (n= 20). Compliance to the clinical pathway occurred in 120 subjects (50.2%). Non-compliance occurred in 71 subjects (29.7%). Forty-eight subjects (20.1%) underwent risk assessments, but subsequent diagnostic tests did not conform to the stated pathway (partial compliance). Compliance was poor in subjects assessed by non-emergency department doctors (χ(2) = 27.95, P≤ 0.001). Compliance occurred less in pregnant subjects (χ(2) = 7.27, P= 0.007) and those with chronic respiratory disease (χ(2) = 5.31, P= 0.021). Subjects in the compliant group were less likely to undergo CTPA (odds ratio 2.07 (1.16-3.70), P= 0.012).

CONCLUSIONS

Compliance with this clinical pathway allowed emergency department doctors in an Australian university teaching hospital to complete diagnostic testing for suspected pulmonary embolism appropriately unless non-emergency department doctors became involved. Compliance with this pathway altered the distribution of diagnostic tests performed with less reliance on CTPA, but was not associated with better patient outcomes.

Pulmonary CT angiography protocol adapted to the hemodynamic effects of pregnancy

OBJECTIVE

The purpose of this study was to compare the image quality of a standard pulmonary CT angiography (CTA) protocol with a pulmonary CTA protocol optimized for use in pregnant patients with suspected pulmonary embolism (PE).

MATERIALS AND METHODS

Forty-five consecutive pregnant patients with suspected PE were retrospectively included in the study: 25 patients (group A) underwent standard-protocol pulmonary CTA and 20 patients (group B) were imaged using a protocol modified for pregnancy. The modified protocol used a shallow inspiration breath-hold and a high concentration, high rate of injection, and high volume of contrast material. Objective image quality and subjective image quality were evaluated by measuring pulmonary arterial enhancement, determining whether there was transient interruption of the contrast bolus by unopacified blood from the inferior vena cava (IVC), and assessing diagnostic adequacy.

RESULTS

Objective and subjective image quality were significantly better for group B-that is, for the group who underwent the CTA protocol optimized for pregnancy. Mean pulmonary arterial enhancement and the percentage of studies characterized as adequate for diagnosis were higher in group B than in group A: 321 ± 148 HU (SD) versus 178 ± 67 HU (p = 0.0001) and 90% versus 64% (p = 0.05), respectively. Transient interruption of contrast material by unopacified blood from the IVC was observed more frequently in group A (39%) than in group B (10%) (p = 0.05).

CONCLUSION

A pulmonary CTA protocol optimized for pregnancy significantly improved image quality by increasing pulmonary arterial opacification, improving diagnostic adequacy, and decreasing transient interruption of the contrast bolus by unopacified blood from the IVC.

Outpatient imaging for pulmonary embolism may only be suitable for a minority

In this study we model the impact of introducing outpatient investigation of pulmonary thrombo-embolism (PTE) to the acute medical unit (AMU) using the Pulmonary Embolism Severity Index (PESI) decision rule. Specifically, we ask what proportion of patients requiring imaging could be investigated without admission, and how many bed-days this would save.  We obtained records for all medical patients who had imaging for PTE in a six-month period at a large teaching hospital with a 40-bedded AMU. The patients were categorized into suitability for outpatient investigation using a combination of the PESI rule and practical considerations. Three hundred and fifty-nine separate presentations were identified. From available records, 31 patients (9.2%, 95% confidence interval [CI] 6.6-12.8%) had no contraindications to outpatient management. These patients used a total of 79 bed-days in the six-month period, or 1.1% (95% CI 0.8-1.5%) of the maximum AMU bed occupancy. Around 10% of patients who require imaging for suspected PTE could be triaged to outpatient investigation using the PESI tool. Adopting this method to triage patients of ambulatory care, would have only a modest effect on acute medical bed occupancy, but remains a valid option for motivated patients in the low-risk category.

Stand-alone performance of a computer-assisted detection prototype for detection of acute pulmonary embolism: a multi-institutional comparison

OBJECTIVE

To assess whether the performance of a computer-assisted detection (CAD) algorithm for acute pulmonary embolism (PE) differs in pulmonary CT angiographies acquired at various institutions.

METHODS

In this retrospective study, we included 40 consecutive scans with and 40 without PE from 3 institutions (n = 240) using 64-slice scanners made by different manufacturers (General Electric; Philips; Siemens). CAD markers were classified as true or false positive (FP) using independent evaluation by two readers and consultation of a third chest radiologist in discordant cases. Image quality parameters were subjectively scored using 4/5-point scales. Image noise and vascular enhancement were measured. Statistical analysis was done to correlate image quality of the three institutions with CAD stand-alone performance.

RESULTS

Patient groups were comparable with respect to age (p = 0.22), accompanying lung disease (p = 0.12) and inpatient/outpatient ratio (p = 0.67). The sensitivity was 100% (34/34), 97% (37/38) and 92% (33/36), and the specificity was 18% (8/44), 15% (6/41) and 13% (5/39). Neither significantly differed between the institutions (p = 0.21 and p = 0.820, respectively). The mean number of FP findings (4.5, 6.2 and 3.7) significantly varied (p = 0.02 and p = 0.03), but median numbers (2, 3 and 3) were comparable. Image quality parameters were significantly associated with the number of FP findings (p<0.05) but not with sensitivity. After correcting for noise and vascular enhancement, the number of FPs did not significantly differ between the three institutions (p = 0.43).

CONCLUSIONS

CAD stand-alone performance is independent of scanner type but strongly related to image quality and thus scanning protocols.

A validation study of the CEMACH recommended modified early obstetric warning system (MEOWS)

The 2003-2005 Confidential Enquiry into Maternal and Child Health report recommended the introduction of the modified early obstetric warning system (MEOWS) in all obstetric inpatients to track maternal physiological parameters, and to aid early recognition and treatment of the acutely unwell parturient. We prospectively reviewed 676 consecutive obstetric admissions, looking at their completed MEOWS charts for triggers and their notes for evidence of morbidity. Two hundred patients (30%) triggered and 86 patients (13%) had morbidity according to our criteria, including haemorrhage (43%), hypertensive disease of pregnancy (31%) and suspected infection (20%). The MEOWS was 89% sensitive (95% CI 81-95%), 79% specific (95% CI 76-82%), with a positive predictive value 39% (95% CI 32-46%) and a negative predictive value of 98% (95% CI 96-99%). There were no admissions to the intensive care unit, cardio respiratory arrests or deaths during the study period. This study suggests that MEOWS is a useful bedside tool for predicting morbidity. Adjustment of the trigger parameters may improve positive predictive value.

Pulmonary embolism: investigation of the clinically assessed intermediate risk subgroup

OBJECTIVES

The simplified Wells pre-test probability scoring algorithm for pre-investigation evaluation of pulmonary emboli (PE) is a commonly utilised and validated assessment tool. We sought to identify whether use of a dichotomised scoring system altered the overall negative predictive value (NPV) in patients referred for CT pulmonary angiography (CTPA) assessment of suspected PE.

METHODS

Prospective data collection of all patients referred for CTPA evaluation of suspected acute PE during a 3 year period was carried out. Pre-test risk stratification was performed according to simplified Wells criteria in conjunction with plasma d-Dimer (Bio-Pool and IL test) estimation. Retrospective dichotomisation was also performed.

RESULTS

2531 patients were investigated for suspected acute PE; acute thromboemboli were confirmed in 22.7%. The overall NPV for negative d-Dimer and intermediate pre-test probability (PTP) was 98.9% [95% confidence interval (CI) 96.3-99.7%]; with retrospective dichotomisation, the NPV for the PE unlikely group was 99.0% (95% CI 94.8-99.8%). Implementation of dichotomised scoring, excluding PE unlikely with negative d-Dimer cases from further imaging, would have yielded a 4% reduction in CTPA referral pathway imaging at our institution.

CONCLUSION

We demonstrate no significant difference between exclusion in the intermediate subgroup and the retrospectively dichotomised PE unlikely group and demonstrate the high negative predictive power of the Bio-Pool and IL tests in conjunction with the Wells PTP tool. Prior to implementation of new guidelines for exclusion of patients with suspected PE from further imaging, hospitals should audit their own practice and validate the d-Dimer assay utilised at their institution.

A retrospective study of the value of indirect CT venography: a British perspective

OBJECTIVE

The aim of this study was to establish the value of indirect CT venography (CTV) in clinical practice within the UK.

METHODS

804 combined CT pulmonary angiogram and CTV studies were retrospectively reviewed. CTV was performed 180 s after the injection of contrast using an incremental technique with a 5-mm collimation and a 5-cm interspace between images extending from the iliac crests to the tibial plateaus.

RESULTS

12.9% of studies had isolated pulmonary emboli (PE), 3.0% had both a PE and deep vein thrombosis (DVT) and 1.1% had an isolated DVT. The proportion of positive cases diagnosed by CTV alone was 6.6%.

CONCLUSION

In a UK-based practice, the incidence and the proportion of isolated DVT diagnosed by CTV are lower than expected from published data. An analysis of possible causes for this is made within the paper.

Influence of population prevalences on numbers of false positives: an overlooked entity

BACKGROUND

Disease prevalence alters the number of true positives (TP), true negatives (TN), false negatives (FN), and false positives (FP), even if the sensitivity and specificity of a test stays the same.

METHODS AND MATERIALS

We illustrate this using data for the detection of suspected acute pulmonary embolism (PE) from the Prospective Investigation of Pulmonary Embolism Diagnosis II (PIOPED II). We chose PE because of the clinical significance of the disease, the low prevalence of PE in the patient population being tested with CTPA with the widespread adoption of CTPA, and the serious clinical consequences of anticoagulation therapy in FP patients.

RESULTS

Based on PIOPED II data (sensitivity 83%, specificity 96%), at a disease prevalence of approximately 5%, the number of FP patients is greater than the number of TP patients. Scaled to the US population, at a disease prevalence of 5%, there would be 139,800 FPs and 3,356,200 TNs. Assuming a mortality rate of 0.5% and a 3.0% rate of major bleeding secondary to anticoagulation therapy for well-controlled patients, if all FP patients received anticoagulation, there would be 699 deaths and 4194 major bleeding complications.

CONCLUSIONS

At a prevalence of approximately 5% for PE, the number of FPs approaches or is greater than the number of TPs for CTPA for the detection of suspected acute PE. Patients with FP results may receive unnecessary, potentially harmful treatment with anticoagulation therapy. Population prevalence of disease needs to be taken into account along with the diagnostic accuracy of a test, because this may significantly affect downstream patient outcomes.

Critical issues in the evaluation and management of adult patients presenting to the emergency department with suspected pulmonary embolism

This clinical policy from the American College of Emergency Physicians is the revision of a 2003 clinical policy on the evaluation and management of adult patients presenting with suspected pulmonary embolism (PE).(1) A writing subcommittee reviewed the literature to derive evidence-based recommendations to help clinicians answer the following critical questions: (1) Do objective criteria provide improved risk stratification over gestalt clinical assessment in the evaluation of patients with possible PE? (2) What is the utility of the Pulmonary Embolism Rule-out Criteria (PERC) in the evaluation of patients with suspected PE? (3)What is the role of quantitative D-dimer testing in the exclusion of PE? (4) What is the role of computed tomography pulmonary angiogram of the chest as the sole diagnostic test in the exclusion of PE? (5) What is the role of venous imaging in the evaluation of patients with suspected PE? (6) What are the indications for thrombolytic therapy in patients with PE? Evidence was graded and recommendations were given based on the strength of the available data in the medical literature.

Time trends in pulmonary embolism in the United States: evidence of overdiagnosis

BACKGROUND

Computed tomographic pulmonary angiography (CTPA) may improve detection of life-threatening pulmonary embolism (PE), but this sensitive test may have a downside: overdiagnosis and overtreatment (finding clinically unimportant emboli and exposing patients to harms from unnecessary treatment).

METHODS

To assess the impact of CTPA on national PE incidence, mortality, and treatment complications, we conducted a time trend analysis using the Nationwide Inpatient Sample and Multiple Cause-of-Death databases. We compared age-adjusted incidence, mortality, and treatment complications (in-hospital gastrointestinal tract or intracranial hemorrhage or secondary thrombocytopenia) of PE among US adults before (1993-1998) and after (1998-2006) CTPA was introduced.

RESULTS

Pulmonary embolism incidence was unchanged before CTPA (P = .64) but increased substantially after CTPA (81% increase, from 62.1 to 112.3 per 100,000; P < .001). Pulmonary embolism mortality decreased during both periods: more so before CTPA (8% reduction, from 13.4 to 12.3 per 100,000; P < .001) than after (3% reduction, from 12.3 to 11.9 per 100,000; P = .02). Case fatality improved slightly before (8% decrease, from 13.2% to 12.1%; P = .02) and substantially after CTPA (36% decrease, from 12.1% to 7.8%; P < .001). Meanwhile, CTPA was associated with an increase in presumed complications of anticoagulation for PE: before CTPA, the complication rate was stable (P = .24), but after it increased by 71% (from 3.1 to 5.3 per 100,000; P < .001).

CONCLUSIONS

The introduction of CTPA was associated with changes consistent with overdiagnosis: rising incidence, minimal change in mortality, and lower case fatality. Better technology allows us to diagnose more emboli, but to minimize harms of overdiagnosis we must learn which ones matter.

Outpatient versus inpatient treatment for patients with acute pulmonary embolism: an international, open-label, randomised, non-inferiority trial

BACKGROUND

Although practice guidelines recommend outpatient care for selected, haemodynamically stable patients with pulmonary embolism, most treatment is presently inpatient based. We aimed to assess non-inferiority of outpatient care compared with inpatient care.

METHODS

We undertook an open-label, randomised non-inferiority trial at 19 emergency departments in Switzerland, France, Belgium, and the USA. We randomly assigned patients with acute, symptomatic pulmonary embolism and a low risk of death (pulmonary embolism severity index risk classes I or II) with a computer-generated randomisation sequence (blocks of 2-4) in a 1:1 ratio to initial outpatient (ie, discharged from hospital ≤24 h after randomisation) or inpatient treatment with subcutaneous enoxaparin (≥5 days) followed by oral anticoagulation (≥90 days). The primary outcome was symptomatic, recurrent venous thromboembolism within 90 days; safety outcomes included major bleeding within 14 or 90 days and mortality within 90 days. We used a non-inferiority margin of 4% for a difference between inpatient and outpatient groups. We included all enrolled patients in the primary analysis, excluding those lost to follow-up. This trial is registered with ClinicalTrials.gov, number NCT00425542.

FINDINGS

Between February, 2007, and June, 2010, we enrolled 344 eligible patients. In the primary analysis, one (0·6%) of 171 outpatients developed recurrent venous thromboembolism within 90 days compared with none of 168 inpatients (95% upper confidence limit [UCL] 2·7%; p=0·011). Only one (0·6%) patient in each treatment group died within 90 days (95% UCL 2·1%; p=0·005), and two (1·2%) of 171 outpatients and no inpatients had major bleeding within 14 days (95% UCL 3·6%; p=0·031). By 90 days, three (1·8%) outpatients but no inpatients had developed major bleeding (95% UCL 4·5%; p=0·086). Mean length of stay was 0·5 days (SD 1·0) for outpatients and 3·9 days (SD 3·1) for inpatients.

INTERPRETATION

In selected low-risk patients with pulmonary embolism, outpatient care can safely and effectively be used in place of inpatient care.

FUNDING

Swiss National Science Foundation, Programme Hospitalier de Recherche Clinique, and the US National Heart, Lung, and Blood Institute. Sanofi-Aventis provided free drug supply in the participating European centres.

Incremental value of CT venography combined with pulmonary CT angiography for the detection of thromboembolic disease: systematic review and meta-analysis

OBJECTIVE

The objective of our study was to assess the incremental role of CT venography (CTV) combined with pulmonary CT angiography (CTA) in detecting venous thromboembolic disease with a systematic review and meta-analysis of the literature.

MATERIALS AND METHODS

MEDLINE, Embase, and Web of Science were searched for relevant original articles published from January 1, 1995, to December 31, 2009. A random-effects model was used to obtain the incremental value of CTV in detecting thromboembolic disease.

RESULTS

Twenty-four studies, which included 17,373 patients, met our inclusion criteria. A meta-analysis showed that CTV increased detection rates of venous thromboembolic disease by identifying an additional 3% of cases (95% CI, 2-4%) of isolated deep venous thrombosis (DVT). A subgroup analysis of a high-risk group did not show any difference in the detection of isolated DVT.

CONCLUSION

The addition of CTV results in the increased detection of thromboembolic disease. CTV combined with pulmonary CTA has a promising role as a quick and efficient test for venous thromboembolism.

Systematic review and meta-analysis on the rate of postoperative venous thromboembolism in orthopaedic surgery in Asian patients without thromboprophylaxis

BACKGROUND

Postoperative venous thromboembolism (VTE) is a common life-threatening complication after surgery. This review analysed the rate and mortality of VTE after orthopaedic surgery in Asia.

METHODS

Inclusion criteria were: prospective study; deep vein thrombosis (DVT) diagnosed by venography or ultrasonography; hip fracture surgery (HFS), total hip arthroplasty (THA) or total knee arthroplasty (TKA); and no thromboprophylaxis. The pooled proportion was back-calculated by Freeman-Tukey variant transformation, using a random-effects model.

RESULTS

Twenty-two studies (total population 2454) published from 1979 to 2009 were included. Using venography, the pooled rates of all-site, proximal, distal and isolated distal DVT were 31·7, 8·9, 22·5 and 18·8 per cent respectively. With duplex ultrasonography, the respective rates were 9·4, 5·9, 5·9 and 5·8 per cent. After THA or HFS, using venography, the pooled rates of all-site and proximal DVT were 25·8 and 9·6 per cent; with ultrasonography, the respective rates were 10·8 and 7·2 per cent. In TKA groups, using venography, the pooled rates of all-site and proximal DVT were 42·5 and 8·7 per cent; with ultrasonography, the respective rates were 9·5 and 5·2 per cent. The overall pooled rates of symptomatic DVT and symptomatic pulmonary embolism (PE) were 4·5 and 0·6 per cent. No patient died from PE (pooled rate 0·2 per cent).

CONCLUSION

None of these Asian patients undergoing orthopaedic surgery died from VTE. Pooled rates of proximal and symptomatic DVT were lower than in Western reports.

Challenges, controversies, and hot topics in pulmonary embolism imaging

OBJECTIVE

The purpose of this article is to discuss the diagnostic role of pulmonary CT angiography (CTA) in the workup of pulmonary embolism (PE), including specific populations, and issues such as pulmonary CTA combined with indirect CT venography; radiation dose considerations; the management of isolated subsegmental PE; and new technologic developments, such as dual-source/dual-energy pulmonary CTA.

CONCLUSION

The role of pulmonary CTA will continue to grow with the emergence of MDCT and dual-energy CT and their improved capabilities. However, the need for any given CT examination should always be justified on the basis of the individual patient's benefits and risks.

How do I manage a patient with suspected acute pulmonary embolism?

Acute PE is a cardiovascular emergency and early risk stratification is important in the management of these patients. Pre-test clinical prediction models together with D-dimer assays help select those who require imaging. Each hospital should develop a strategy for investigating patients with suspected PE depending on local expertise, resources and the patient population.

Underlying cause discovered for a prior idiopathic AMI

The authors previously reported on an active, young male with normal coronaries who sustained an acute myocardial infarction (AMI). The acute cause was a coronary thrombus; however, the cause of this thrombus and a definitive diagnosis remained elusive for 18 months until a new series of events, including symptoms of breathlessness, dizziness and collapse led to acute hospital admission. CT scan revealed numerous deep venous thromboses in the right leg and bilateral pulmonary emboli (PE). Acute pharmacological thrombolysis eliminated breathlessness and significantly reduced the risk of mortality. Clinical consensus suggests a coagulopathy, requiring indefinite treatment with Warfarin. In young individuals presenting with AMI, lifestyle, personal, family and clinical history should be considered and coronary artery disease should not be assumed until further tests have eliminated coagulopathy. In those presenting with breathlessness and a history which includes AMI, a CT scan is indicated to eliminate concerns of venous thromboembolism generally and PE specifically where untreated survival times are short.

Thromboembolism

INTRODUCTION

Deep venous thrombosis (DVT) or pulmonary embolism may occur in almost 2 in 1000 people each year, with up to 25% of those having a recurrence. Around 5% to 15% of people with untreated DVT may die from pulmonary embolism. Risk factors for DVT include immobility, surgery (particularly orthopaedic), malignancy, pregnancy, older age, and inherited or acquired prothrombotic clotting disorders.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments for proximal DVT? What are the effects of treatments for isolated calf DVT? What are the effects of treatments for pulmonary embolism? What are the effects of interventions on oral anticoagulation management in people with thromboembolism? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 45 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review we present information relating to the effectiveness and safety of the following interventions: anticoagulation; compression stockings; low molecular weight heparin (short and long term, once or twice daily, and home treatment); oral anticoagulants (short and long term, high intensity, abrupt discontinuation, and computerised decision support); prolonged duration of anticoagulation; thrombolysis; vena cava filters; and warfarin.

Are biomarkers additive to pulmonary embolism severity index for severity assessment in normotensive patients with acute pulmonary embolism?

BACKGROUND

Biomarkers and clinical prediction rules have been proposed for severity assessment in acute pulmonary embolism (PE).

AIM

The aim of this study was to compare biomarkers with the PE Severity Index (PESI), a validated scoring system for predicting 30-day mortality and to determine if addition of biomarkers to PESI would improve its predictive accuracy.

STUDY DESIGN AND METHODS

We conducted a retrospective analysis of normotensive patients admitted with PE confirmed by CT pulmonary angiogram, to three teaching hospitals between January 2005 and July 2007. All patients had admission levels of D-dimer and Troponin I and calculation of PESI score on admission. The outcome of interest was 30-day mortality.

RESULTS

There were 411 patients included in the study. Patients who died had higher levels of D-dimer (median 2947 ng/ml vs. 1464 ng/ml; P=0.02), Troponin (57.1% positive vs. 13.8%; P<0.0001) and higher PESI scores [median 109 vs. 83; P<0.0001], compared to survivors. PESI had superior accuracy for predicting 30-day mortality than a combination of Troponin and D-dimer (AUC 0.80 vs. 0.75). Addition of Troponin to PESI further improved the predictive value of the score (AUC 0.85 for vs. AUC 0.80 for PESI alone).

CONCLUSION

Biomarkers and clinical prediction rules predict outcome in acute PE. Addition of troponin to the PESI scoring system improves the predictive value for 30-day mortality and may be useful for guiding initial management of patients presenting with PE.

Methodology for ventilation/perfusion SPECT

Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas over radiolabeled liquid aerosols are not restricted to the presence of obstructive lung disease. Radiolabeled macroaggregated human albumin is the imaging agent of choice for perfusion scintigraphy. An optimal combination of nuclide activities and acquisition times for ventilation and perfusion, collimators, and imaging matrix yields an adequate V/Q SPECT study in approximately 20 minutes of imaging time. The recommended protocol based on the patient remaining in an unchanged position during the initial ventilation study and the perfusion study allows presentation of matching ventilation and perfusion slices in all projections as well as in rotating volume images based upon maximum intensity projections. Probabilistic interpretation of V/Q SPECT should be replaced by a holistic interpretation strategy on the basis of all relevant information about the patient and all ventilation/perfusion patterns. PE is diagnosed when there is more than one subsegment showing a V/Q mismatch representing an anatomic lung unit. Apart from pulmonary embolism, other pathologies should be identified and reported, for example, obstructive disease, heart failure, and pneumonia. Pitfalls exist both with respect to imaging technique and scan interpretation.

Incidental cardiac findings on computed tomography imaging of the thorax

Background

Investigation of pulmonary pathology with computed tomography also allows visualisation of the heart and major vessels. We sought to explore whether clinically relevant cardiac pathology could be identified on computed tomography pulmonary angiograms (CTPA) requested for the exclusion of pulmonary embolism (PE). 100 consecutive CT contrast-enhanced pulmonary angiograms carried out for exclusion of PE at a single centre were assessed retrospectively by two cardiologists.

Findings

Evidence of PE was reported in 5% of scans. Incidental cardiac findings included: aortic wall calcification (54%), coronary calcification (46%), cardiomegaly (41%), atrial dilatation (18%), mitral annulus calcification (15%), right ventricular dilatation (11%), aortic dilatation (8%) and right ventricular thrombus (1%). Apart from 3 (3%) reports describing cardiomegaly, no other cardiac findings were described in radiologists' reports. Other reported pulmonary abnormalities included: lung nodules (14%), lobar collapse/consolidation (8%), pleural effusion (2%), lobar collapse/consolidation (8%), emphysema (6%) and pleural calcification (4%).

Conclusions

CTPAs requested for the exclusion of PE have a high yield of cardiac abnormalities. Although these abnormalities may not have implications for acute clinical management, they may, nevertheless, be important in long-term care.

[Recommendations for the management of pulmonary thromboembolism, 2010]

Pulmonary thromboembolism and deep vein thrombosis together constitute a condition designated venous thromboembolism. Despite the advances, the morbidity and the mortality attributed to this condition are still high, because the patients present with more complex diseases, are submitted to a greater number of invasive procedures and survive longer. Although there are various international guidelines available, we decided to write these recommendations for their application in medical practice in Brazil. These recommendations are based on the best evidence in the literature and the opinion of the advisory committee. This document is only a tool for use in the management of patients. Although the recommendations it contains can be applied to most situations, physicians should adapt its content depending on their local context and on a case-by-case basis. Pulmonary thromboembolism is diagnosed by evaluating pre-test clinical probability (scores) together with the results of imaging studies, the current method of choice being CT angiography. Stratification of the risk for an unfavorable outcome is fundamental. Hemodynamic instability is the most important predictor. Low-risk patients should be treated with heparin, commonly low-molecular-weight heparins. High-risk patients require intensive monitoring and, in some cases, thrombolytic therapy. In the long term, patients should receive anticoagulants for at least three months. The decision to prolong this treatment is made based on the presence of risk factors for the recurrence of the condition and the probability of bleeding. Prophylaxis is highly effective and should be widely used in clinical and surgical patients alike, according to their risk group. Finally, we include recommendations regarding the prevention, diagnosis and treatment of pulmonary thromboembolism.

Imaging for suspected pulmonary embolism in pregnancy-what about the fetal dose? A comprehensive review of the literature

OBJECTIVE: To give a comprehensive overview of fetal doses reported in the literature when imaging the pregnant woman with suspected pulmonary embolism (PE). METHODS: A comprehensive literature search in the PubMed, MEDLINE and EMBASE databases yielded a total of 1,687 papers that were included in the analysis and have been analysed with regard to fetal dose in suspected PE radiological imaging strategies. RESULTS: Fetal dose in chest computed tomography (CT) ranges between 0.013 and 0.026 mGy in early and 0.06-0.1 mGy in late pregnancy compared with 99mTc-MAA perfusion scintigraphy with a fetal dose of 0.1-0.6 mGy in early and 0.6-0.8 mGy in late pregnancy. (99m)Tc-aerosol ventilation scintigraphy results in 0.1-0.3 mGy. However, there is concern about female breast irradiation in CT, which is higher than in scintigraphy. CT radiation risks for breast tissue remain unclear. CONCLUSION: Knowledge of dosimetry and radiation risks is crucial in the radiological work-up of suspected PE in pregnancy. It is reasonable to reserve scintigraphy for pregnant patients with normal chest radiography findings and no history of asthma or chronic lung disease. Performing CT applying dose reduction instead of scintigraphy will minimise fetal radiation dose and maximise the diagnostic value.

Hereditary haemorrhagic telangiectasia: pathophysiology, diagnosis and treatment

Hereditary haemorrhagic telangiectasia, inherited as an autosomal dominant trait, affects approximately 1 in 5000 people. The abnormal vascular structures in HHT result from mutations in genes (most commonly endoglin or ACVRL1) whose protein products influence TGF-ß superfamily signalling in vascular endothelial cells. The cellular mechanisms underlying the generation of HHT telangiectasia and arteriovenous malformations are being unravelled, with recent data focussing on a defective response to angiogenic stimuli in particular settings. For affected individuals, there is often substantial morbidity due to sustained and repeated haemorrhages from telangiectasia in the nose and gut. Particular haematological clinical challenges include the management of severe iron deficiency anaemia; handling the intricate balance of antiplatelet or anticoagulants for HHT patients in whom there are often compelling clinical reasons to use such agents; and evaluation of apparently attractive experimental therapies promoted in high profile publications when guidelines and reviews are quickly superseded. There is also a need for sound screening programmes for silent arteriovenous malformations. These occur commonly in the pulmonary, cerebral, and hepatic circulations, may haemorrhage, but predominantly result in more complex pathophysiology due to consequences of defective endothelium, or shunts that bypass specific capillary beds. This review will focus on the new evidence and concepts in this complex and fascinating condition, placing these in context for both clinicians and scientists, with a particular emphasis on haematological settings.