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Original Research: PULMONARY VASCULAR DISEASE |

Prognostic Models for Selecting Patients With Acute Pulmonary Embolism for Initial Outpatient Therapy* FREE TO VIEW

David Jiménez, MD; Roger D. Yusen, MD, FCCP; Remedios Otero, MD; Fernando Uresandi, MD; Dolores Nauffal, MD; Elena Laserna, MD; Francisco Conget, MD; Mikel Oribe, MD; Miguel A. Cabezudo, MD; Gema Díaz, MD
Author and Funding Information

*From the Respiratory Department (Dr. Jiménez), Ramón y Cajal Hospital, Madrid, Spain; Division of Pulmonary and Critical Care Medicine (Dr. Yusen), Washington University School of Medicine, St. Louis, MO; Respiratory Department (Drs. Otero and Laserna), Virgen del Rocío Hospital, Sevilla, Spain; Respiratory Department (Dr. Uresandi), Cruces Hospital, Bizkaia, Spain; Respiratory Department (Dr. Nauffal), La Fe Hospital, Valencia, Spain; Respiratory Department (Dr. Conget), Lozano Blesa Hospital, Zaragoza, Spain; Respiratory Department (Dr. Oribe), Galdakao Hospital, Galdakao, Spain; Respiratory Department (Dr. Cabezudo), Oviedo Hospital, Oviedo, Spain; and Respiratory Department (Dr. Diaz), Zarzuela Hospital, Madrid, Spain.

Correspondence to: David Jiménez, MD, Respiratory Department. Ramón y Cajal Hospital, Department of Medicine, Alcalá de Henares University, 28034 Madrid, Spain 913368314; e-mail: djc_69_98@yahoo.com



Chest. 2007;132(1):24-30. doi:10.1378/chest.06-2921
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Published online

Objective: To assess the performance of two prognostic models in predicting short-term mortality in patients with pulmonary embolism (PE).

Subjects and methods: We compared the test characteristics of two prognostic models for predicting 30-day outcomes (mortality, thromboembolic recurrences, and major bleeding) in a cohort of 599 patients with objectively confirmed PE. Patients were stratified into the PE severity index (PESI) risk classes I-V and the Geneva low-risk and high-risk strata. We compared the discriminatory power of both prognostic models.

Results: The PESI classified fewer patients as low risk (strata I and II) [36%; 216 of 599 patients; 95% confidence interval (CI), 32 to 40%] compared to the Geneva prediction rule (84%; 502 of 599 patients; 95% CI, 81 to 87%) [p < 0.0001]. Using either prediction rule, the low-risk groups showed statistically relevant 30-day mortality difference (PESI, 0.9%; 95% CI, 0.3 to 2.2; vs Geneva, 5.6%; 95% CI, 3.6 to 7.6) [p < 0.0001], although nonfatal recurrent venous thromboembolism or major bleeding rates were statistically similar (PESI, 2.8%; 95% CI, 0.6 to 5.0%; vs Geneva, 4.2%; 95% CI, 2.4 to 5.9%). The area under the receiver operating characteristic curve was higher for the PESI (0.76; 95% CI, 0.69 to 0.83) than for the Geneva score (0.61; 95% CI, 0.51 to 0.71) [p = 0.002].

Conclusions: The PESI quantified the prognosis of patients with PE better than the Geneva score. This study demonstrated that PESI can select patients with very low adverse event rates during the initial days of acute PE therapy and assist in selecting patients for treatment in the outpatient setting.

Figures in this Article

Traditionally, clinicians have treated patients with acute deep vein thrombosis (DVT) or pulmonary embolism (PE) in the hospital with IV unfractionated heparin. Patients typically receive this initial therapy until they are successfully converted over to oral vitamin K antagonist therapy. Over the past decade, subcutaneously administrated low molecular weight heparins have replaced much of IV unfractionated heparin therapy and have facilitated outpatient DVT therapy because of their rapid antithrombotic effect, fixed weight-based dose, and lack of need for daily anticoagulant monitoring.14 Although most patients with acute PE remain hospitalized during initial therapy, some may be suitable for partial or complete outpatient management. Since a small but significant proportion of patients with acute PE will die or have bleeding or thromboembolic complications during the initial therapy period, reliable prognostic information at presentation would help clinicians to risk stratify patients for ambulatory treatment.

In a prospective study of 296 outpatients admitted at the emergency center of the University Hospital of Geneva with confirmed symptomatic acute PE, Wicki et al5identified six independent predictors (cancer, heart failure, previous DVT, systolic BP < 100 mm Hg, Pao2 < 8 kPa, presence of DVT on ultrasound) of an adverse outcome (death, recurrent thromboembolic event, or major bleeding) in a 3-month follow-up period. Nendaz et al6 externally validated this “Geneva” prediction rule on a distinct set of emergency ward patients.

Aujesky et al7 have developed a clinical prediction rule (PE severity index [PESI]) to classify patients with acute PE into categories of increasing risk of mortality and other adverse medical outcomes. In this study7of 15,531 inpatients discharged with PE from 186 Pennsylvania hospitals, 11 factors independently associated with 30-day mortality included age, male gender, cancer, heart failure, chronic lung disease, pulse rate ≥ 110 beats/min, systolic BP < 100 mm Hg, respiratory rate ≥ 30 breaths/min, temperature < 36°C, altered mental status, and oxyhemoglobin saturation < 90%. Aujesky et al8 recently validated this model in 367 patients with PE prospectively diagnosed at 117 European emergency departments.

Given that the PESI and the Geneva score have not yet been directly compared nor have they been validated by independent investigators, this study aimed to assess, compare, and externally validate the Geneva prediction rule and the PESI on a distinct set of ambulatory patients with acute symptomatic PE. The study also assessed the ability of the prediction rules to identify low-risk patients with acute PE for treatment in the outpatient setting.

Study Design

For a prospective registry, we attempted to enroll all patients with a diagnosis of acute PE between January 1, 2003, and September 30, 2006. Using prospectively collected baseline data at the time of PE diagnosis and outcome data from this cohort, we retrospectively assessed the test characteristics of the Geneva prognostic model and the PESI for predicting 30-day mortality, nonfatal recurrent venous thromboembolism (VTE), and nonfatal major bleeding. We also compared the performance of both prognostic models between the validation and the original derivation samples. We then assessed the ability of the prediction rules to identify low-risk patients with acute PE for treatment in the outpatient setting. All patients provided informed consent for their participation in the prospective registry in accordance with the requirements of the ethics committee of the hospital, and this study was approved by the human subjects committee.

Patients, Setting, and Eligibility Criteria

Patients were recruited from the Emergency Department of Ramón y Cajal Hospital, Madrid, Spain. Eligible patients were required to have acute symptomatic PE confirmed by objective testing. A diagnosis of PE was confirmed by either a high-probability ventilation-perfusion scan result according to the criteria of the Prospective Investigation of Pulmonary Embolism Diagnosis,9a lower-limb venous compression ultrasonography positive for a proximal DVT in patients with inconclusive ventilation-perfusion scan findings,10or previously described criteria to detect acute PE on contrast-enhanced PE-protocol helical chest CT.11

Study End Points

The primary outcome used to validate the prediction rules was all-cause mortality 30 days after diagnosis of acute symptomatic PE. The secondary outcome was objectively confirmed nonfatal symptomatic recurrent VTE, or nonfatal major bleeding. We assessed mortality using patient or proxy interviews, and/or hospital chart review. Patients with symptoms or signs of recurrent VTE were evaluated with objective tests. Recurrent DVT was diagnosed by the appearance of a new noncompressible vein segment, or a ≥ 4-mm increase in the diameter of a thrombus on venous ultrasound, or a new intraluminal filling defect or an extension of a previous filling defect on a venogram.12 Recurrent PE was confirmed either by a new perfusion scan defect involving ≥ 75% of a lung segment, or by the presence of a new intraluminal filling defect or an extension of a previous filling defect on helical chest CT.11 Trained attending radiologists blinded to patient clinical information assessed the imaging studies. Bleeding complications were classified as “major” if they were overt and were either associated with a decrease in the hemoglobin level ≥ 2.0 g/dL, required a transfusion of ≥ 2 U of blood, or were retroperitoneal or intracranial.

Treatment

Patients were initially hospitalized and treated with therapeutic doses of parenteral anticoagulants (IV unfractionated heparin or weight-based doses of subcutaneous low-molecular-weight heparin [enoxaparin]) while they were converted to oral vitamin K antagonist therapy. Thrombolytic treatment was instituted in patients with confirmed PE and hemodynamic impairment as deemed appropriate by the attending physician. After the initial “overlap” treatment period, patients were continued on dose-adjusted oral vitamin K antagonist therapy (acenocoumarol; target international normalized ratio of 2.5; therapeutic range, 2.0 to 3.0). The international normalized ratio was usually monitored daily until the therapeutic range had been achieved, then twice or three times weekly for the first weeks, and then once a week to once a month, depending on the stability of the results. Patients with contraindications due to anticoagulant therapy had an inferior vena cava filter placed and the anticoagulant discontinued.

Statistical Analysis

Baseline characteristics are described with mean ± SD for continuous data and counts and proportions for categorical data. Each patient’s baseline characteristics determined their risk classification according to the criteria for each predictive model. For the PESI, risk classes I and II were assigned to the low-risk category, while risk classes III-V were assigned to the high-risk category. For the Geneva model, patients were assigned to low-risk and high-risk categories according to the published criteria.5 For each risk class of the prognostic model, the proportion of patients with 30-day adverse outcomes (all-cause mortality, or nonfatal recurrent VTE and nonfatal major bleeding) were determined. Proportions of patients in derivation and validation cohort risk classes and proportions of patients with adverse events among groups were compared with the χ2 test with Yates correction or Fisher exact test, and the McNemar test. To assess the test and performance characteristics of the low-risk vs high-risk categories for each prediction rules, we estimated sensitivity, specificity, and positive and negative predictive values. We assessed the discriminatory power of each prediction rule by calculating the area under each receiver operating characteristic (ROC) curve (C-statistic), and we compared the C-statistics for the two predictive models. Ninety-five percent confidence intervals (CI) were computed form the binomial distribution using statistical software (Statistical Package for Social Sciences, version 11.5; SPSS; Chicago, IL).

Of the 2,219 patients evaluated for possible acute symptomatic PE during the study period, 624 patients (28%) had objectively confirmed PE. Of these, 9 patients (1.4%) refused to give informed consent, producing a study sample of 615 patients. Since 16 patients (2.6%) were unavailable for follow-up, the evaluable population consisted of 96.0% (599 patients) of eligible patients with acute PE.

Compared to patients in the PESI derivation sample,7 patients in this validation cohort more frequently had an arterial oxyhemoglobin saturation < 90%, and less frequently had heart failure, chronic lung disease, tachycardia, tachypnea, or a temperature < 36°C. Compared to patients in the Geneva derivation sample,5 patients in this validation cohort more frequently had systolic hypotension and less frequently had tachycardia, tachypnea, or heart failure (Table 1 ).

Compared with the derivation cohorts in which the PESI and Geneva prediction rules were derived, the proportions of patients within each risk class were significantly different in the validation cohort (Table 2 ). Using patients in this validation cohort, the PESI classified a significantly lower proportion of patients as low risk (risk class I or II) [36%; 216 of 599 patients] than the Geneva risk score (84%; 502 of 599 patients) [p < 0.0001].

Of the 599 patients in the validation cohort, 43 patients (7.2%; 95% CI, 5.1 to 9.%2) died within 30 days of presentation, a similar proportion than seen in the PESI derivation cohort (7.2% vs 9.2%; p = 0.11). In the validation cohort, each of the PESI and Geneva predictive models appropriately showed higher mortality in the higher-risk categories.

Both prediction rules had mortality in the low-risk groups < 6% and mortality in the high-risk groups of at least 10%. Compared to the Geneva score low-risk patients (5.6% mortality), the PESI low-risk patients (classes I and II) had a significantly lower mortality rate (0.9%; p < 0.0001). The PESI high-risk patients had a slightly lower mortality rate (10.7%; 41 of 383 patients) compared to the Geneva high-risk patients (15.5%; 15 of 97 patients).

The PESI had a higher sensitivity and a lower specificity than the Geneva score for predicting 30-day mortality (Table 3 ). The negative predictive values were high (> 95%), and the positive predictive values were low across all high-risk classification thresholds for the PESI and the Geneva prediction rule. The negative predictive value for mortality was 99% for PESI low-risk strata. When all 30-day adverse events were considered, the negative predictive value for PESI low-risk strata was 97% (Table 4 ).

The PESI (C-statistic, 0.76; 95% CI, 0.69 to 0.83) had a greater discriminatory power to predict 30-day mortality than the Geneva score (C-statistic, 0.61; 95% CI, 0.51 to 0.71) [p = 0.002; Fig 1 ]. The discriminatory power of the two prediction rules was similar for the prediction of nonfatal adverse events (recurrent VTE or major hemorrhage) within the first month after the diagnosis of acute PE (Fig 2 ).

Comment

This study provides further evidence that the PESI can successfully risk stratify patients with acute PE for 30-day mortality. However, the Geneva low risk strata do not identify patients with acute PE that have negligible risk for 30-day mortality.

Despite modern methods for diagnosis and treatment, PE continues to have a high mortality rate.13Prognostic models for patients with PE could be helpful in guiding medical decision making. For example, patients estimated to be at low risk could be discharged early or managed entirely as outpatients,1417 whereas patients estimated as high risk may benefit from a more intensive surveillance in an intensive care setting. Prediction rules with better test characteristics are needed to identify patients who would be at low-risk for death and adverse events such as major bleeding and recurrent VTE during initial acute PE therapy. If such patients could be identified, then safe outpatient PE therapy could be facilitated. The most important period to prognosticate for possible outpatient therapy would be first weeks after the diagnosis when patients are typically hospitalized, and neither the PESI study nor the Geneva study had enough deaths or adverse events during this time period to adequately develop their prediction rules.

Using our validation cohort, the PESI and the Geneva model showed a large discrepancy in the classification of low-risk patients. The PESI classified fewer patients into the low-risk strata than in previous studies. However, this score was still able to identify approximately 25% of patients who had a very low risk of an adverse event, and if all of them were treated as outpatients it would lead to substantial cost savings18 and likely increased patient satisfaction. The two models demonstrated different rates of outcomes for the low-risk groups. The PESI demonstrated a higher discriminatory power for predicting 30-day mortality than the Geneva score. Low-risk patients identified using the PESI (classes I and II) had a lower mortality and a higher negative predictive value for death than low-risk patients identified using the Geneva score. Low-risk patients identified by the PESI showed a negligible 30-day risk of death as shown by a negative predictive value of 99%. The negative predictive value of 97% for 30-day adverse events in the low-risk categories makes this score very useful for selecting patients for outpatient treatment.

For our sample, the area under the ROC curve using the PESI was similar to the original derivation study (C-statistics, 0.76 vs 0.78). However, the performance of the Geneva score in our sample was significantly lower than the one of the derivation study (C-statistics, 0.61 vs 0.82). The Geneva score area under the ROC curve was lower than that seen with the PESI. A possible explanation is that the Geneva score was originally designed to predict 3-month adverse events.

One crucial issue in the validation of a prognostic rule for PE is a detailed description of the patients studied. Our study sample included only consecutive ambulatory patients presenting to the emergency department of a tertiary-care urban university hospital. The outpatient sample of patients (with a lower comorbidity than the derivation samples) might explain the slightly lower 30-day mortality rate compared to previous studies. Since we were interested in validating the prediction rules in patients that might be suitable for outpatient acute PE therapy, we excluded patients with in-hospital diagnosis of PE because outpatient treatment is not feasible for such patients. The exclusion of patients with autopsy-discovered PE, in which the diagnosis had not been suspected before death, may also explain our lower 30-day mortality compared to the PESI derivation study.

Our validation study has several strengths that pertain to assessment of prediction rules for identification of low-risk patients during initial acute PE therapy. The study sample included consecutive patients with symptomatic, objectively confirmed acute PE who underwent evaluation in our emergency department. Detailed baseline data were collected on all patients. Thus, this study population may reflect the wide prognostic spectrum of patients with PE in which ambulatory treatment may be considered.

There are several limitations to our study that should be acknowledged. First, some of the difficulties in validating the prediction rules on this study cohort relate to the prediction rule development methodology. The PESI and the Geneva prediction rule were developed to predict different outcomes over different lengths of time after the diagnosis of acute PE (PESI, 30-day mortality; Geneva score, 3-month adverse events). Second, the validity of the prediction rules might be improved by incorporating additional or different prognostic markers that have been shown to be useful for stratifying prognosis in patients with PE, such as troponin levels,1920 brain natriuretic peptide levels,2122 echocardiographic findings,23or CT pulmonary angiography findings.24 Third, if prediction rules are used to determine the eligibility of patients with acute PE for initial outpatient management, they should exclude patients that require inpatient management (eg, patients with respiratory failure, hemodynamic instability, need of mechanical ventilation, or need of IV analgesia). For example, in our series 5% of patients classified in PESI risk classes I and II had a new requirement for supplemental oxygen (defined as an oxyhemoglobin saturation < 90%). Finally, since the validation cohort was initially treated in hospital, these results need to be confirmed in a study of outpatient therapy in a low-risk population.

In conclusion, very good diagnostic accuracy was demonstrated for the prediction of short-term mortality in patients with acute PE by the PESI. This models was very useful for identifying patients who can undergo initial acute PE therapy with low risk for major adverse events of recurrent VTE, major bleeding, and death within the first weeks of therapy. Randomized studies comparing outpatient to in-hospital treatment of patients with PE are needed.

Abbreviations: CI = confidence interval; DVT = deep vein thrombosis; PE = pulmonary embolism; PESI = pulmonary embolism severity index; ROC = receiver operating characteristic; VTE = venous thromboembolism

Drs. D. Jiménez, R. Otero, F. Uresandi, D. Nauffal, E. Laserna, F. Conget, M. Oribe, and M.A. Cabezudo are investigators in the Cooperative Study for the Ambulatory Treatment of Patients With Pulmonary Embolism research group.

Then authors have no conflicts of interest to disclose.

Table Graphic Jump Location
Table 1. Demographic and Clinical Characteristics of the Patients in the Validation Cohort
* 

In the validation sample, 3% of the patient had unknown values for systolic BP, 14.2% for temperature, and 17.5% for arterial oxyhemoglobin saturation. For calculating the frequency of baseline patient characteristics, unknown values were assumed to be normal and were included in the denominator in both samples.

 

Percentage of patients with age > 65 years.

 

Percentage of patients with COPD.

§ 

Pecentage of patients with pulse rate > 100 beats/min.

 

Percentage of patients with respiratory rate > 30 breaths/min.

 

p < 0.0001, PESI derivation sample vs validation cohort.

# 

p < 0.0001, Geneva derivation sample vs validation cohort.

** 

p = 0.003, Geneva derivation sample vs validation cohort.

Table Graphic Jump Location
Table 2. Validation Cohort 30-Day Mortality and Adverse Events Within Risk Strata Derived From the PESI and the Geneva Prediction Rule*
* 

Data are presented as % (95% CI).

 

Per risk stratum.

 

p < 0.0001, PESI derivation sample vs validation cohort.

§ 

p < 0.01, PESI derivation sample vs validation cohort.

 

p < 0.0001, Geneva derivation sample vs validation cohort.

 

p = 0.02, Geneva derivation sample vs validation cohort.

Table Graphic Jump Location
Table 3. Prediction Rule Test Characteristics for 30-Day Mortality in the Validation Cohort*
* 

Data are presented as % (95% CI).

Table Graphic Jump Location
Table 4. Prediction Rule Test Characteristics for 30-Day Adverse Events in the Validation Cohort*
* 

Data are presented as % (95% CI).

Figure Jump LinkFigure 1. ROC curves for 30-day mortality for the PESI and the Geneva prediction rule in this validation cohort.Grahic Jump Location
Figure Jump LinkFigure 2. ROC curves for 30-day adverse events for the PESI and the Geneva prediction rule in this validation cohort.Grahic Jump Location
Levine, M, Gent, M, Hirsh, J, et al (1996) A comparison of low-molecular-weight heparin administered primarily at home with unfractionated heparin administered in the hospital for proximal deep-vein thrombosis.N Engl J Med334,677-681. [PubMed] [CrossRef]
 
Koopman, M, Prandoni, P, Piovella, F, et al Treatment of venous thrombosis with intravenous unfractionated heparin administered in the hospital as compared with subcutaneous low-molecular-weight heparin administered at home.N Engl J Med1996;334,682-687. [PubMed]
 
Wells, PS, Kovacs, MJ, Bormanis, J, et al Expanding eligibility for outpatient treatment of deep venous thrombosis and pulmonary embolism with low-molecular-weight heparin.Arch Intern Med1998;158,1809-1812. [PubMed]
 
Yusen, RD, Gage, BF Outpatient treatment of acute venous thromboembolic disease.Clin Chest Med2003;24,49-61. [PubMed]
 
Wicki, J, Perrier, A, Perneger, TV, et al Predicting adverse outcome in patients with acute pulmonary embolism: a risk score.Thromb Haemost2000;84,548-552. [PubMed]
 
Nendaz, MR, Bandelier, P, Aujesky, D, et al Validation of a risk score identifying patients with acute pulmonary embolism, who are at low risk of clinical adverse outcome.Thromb Haemost2004;91,1232-1236. [PubMed]
 
Aujesky, D, Obrosky, DS, Stone, RA, et al Derivation and validation of a prognostic model for pulmonary embolism.Am J Respir Crit Care Med2005;172,1041-1046. [PubMed]
 
Aujesky, D, Roy, PM, Le Manach, CP, et al Validation of a model to predict adverse outcomes in patients with pulmonary embolism.Eur Heart J2006;27,476-481. [PubMed]
 
PIOPED Investigators.. Value of ventilation/perfusion scan in acute pulmonary embolism: results of the prospective investigation of the pulmonary embolism diagnosis (PIOPED).JAMA1990;263,2753-2759. [PubMed]
 
Turkstra, F, Kiujer, PM, van Beek, E, et al Diagnostic utility of ultrasonography of leg veins in patients suspected of having pulmonary embolism.Ann Intern Med1997;126,775-781. [PubMed]
 
Remy-Jardin, M, Remy, J, Wattinne, L, et al Central pulmonary thromboembolism: diagnosis with spiral volumetric CT with the single-breath-hold-technique-comparison with pulmonary angiography.Radiology1992;185,381-387. [PubMed]
 
Prandoni, P, Cogo, A, Bernardi, E, et al A simple approach for detection of recurrent proximal vein thrombosis.Circulation1993;88,1730-1735. [PubMed]
 
Goldhaber, SZ, Visana, L, De Rosa, M Acute pulmonary embolism: clinical outcomes in the International Cooperative Pulmonary Embolism Registry (ICOPER).Lancet1999;353,1386-1389. [PubMed]
 
Zidane, M, van Hulsteijn, LH, Brenninkmeijer, BJ, et al Out of hospital treatment with subcutaneous low molecular weight heparin in patients with acute deep-vein thrombosis: a prospective study in daily practice.Haematologica2006;91,1052-1058. [PubMed]
 
Beer, JH, Burger, M, Gretener, S, et al Outpatient treatment of pulmonary embolism is feasible and safe in a substantial proportion of patients.J Thromb Haemost2003;1,186-187. [PubMed]
 
Kovacs, MJ, Anderson, D, Morrow, B, et al Outpatient treatment of pulmonary embolism with dalteparin.Thromb Haemost2000;83,209-211. [PubMed]
 
Lim, AY, Parr, DG, Stableforth, DE, et al Early discharge and home supervision of patients with pulmonary embolism treated with low-molecular weight heparin.Eur J Intern Med2003;14,89-93. [PubMed]
 
Aujesky, D, Smith, KJ, Cornuz, J, et al Cost-effectiveness of low-molecular-weight heparin for treatment of pulmonary embolism.Chest2005;128,1601-1610. [PubMed]
 
Konstantinides, S, Geibel, A, Olschewski, M, et al Importance of cardiac troponin in risk stratification of patients with acute pulmonary embolism.Circulation2002;106,1263-1268. [PubMed]
 
Douketis, JD, Leewenkamp, O, Grobara, P, et al The incidence and prognostic significance of elevated cardiac troponin in patients with submassive pulmonary embolism.J Thromb Haemost2005;3,508-513. [PubMed]
 
Binder, L, Pieske, B, Olschewski, M, et al N-terminal pro-brain natriuretic peptide or troponin testing followed by echocardiography for risk stratification of acute pulmonary embolism.Circulation2005;112,1573-1579. [PubMed]
 
Krüger, S, Graf, J, Merx, MW, et al Brain natriuretic peptide predicts right heart failure in patients with acute pulmonary embolism.Am Heart J2004;147,60-65. [PubMed]
 
Goldhaber, SZ Thrombolytic therapy for patients with pulmonary embolism who are hemodynamically stable but have right ventricular dysfunction.Arch Intern Med2005;165,2197-2199. [PubMed]
 
Ghuysen, A, Ghaye, B, Willems, V, et al Computed tomographic pulmonary angiography and prognostic significance in patients with acute pulmonary embolism.Thorax2005;60,956-961. [PubMed]
 

Figures

Figure Jump LinkFigure 1. ROC curves for 30-day mortality for the PESI and the Geneva prediction rule in this validation cohort.Grahic Jump Location
Figure Jump LinkFigure 2. ROC curves for 30-day adverse events for the PESI and the Geneva prediction rule in this validation cohort.Grahic Jump Location

Tables

Table Graphic Jump Location
Table 1. Demographic and Clinical Characteristics of the Patients in the Validation Cohort
* 

In the validation sample, 3% of the patient had unknown values for systolic BP, 14.2% for temperature, and 17.5% for arterial oxyhemoglobin saturation. For calculating the frequency of baseline patient characteristics, unknown values were assumed to be normal and were included in the denominator in both samples.

 

Percentage of patients with age > 65 years.

 

Percentage of patients with COPD.

§ 

Pecentage of patients with pulse rate > 100 beats/min.

 

Percentage of patients with respiratory rate > 30 breaths/min.

 

p < 0.0001, PESI derivation sample vs validation cohort.

# 

p < 0.0001, Geneva derivation sample vs validation cohort.

** 

p = 0.003, Geneva derivation sample vs validation cohort.

Table Graphic Jump Location
Table 2. Validation Cohort 30-Day Mortality and Adverse Events Within Risk Strata Derived From the PESI and the Geneva Prediction Rule*
* 

Data are presented as % (95% CI).

 

Per risk stratum.

 

p < 0.0001, PESI derivation sample vs validation cohort.

§ 

p < 0.01, PESI derivation sample vs validation cohort.

 

p < 0.0001, Geneva derivation sample vs validation cohort.

 

p = 0.02, Geneva derivation sample vs validation cohort.

Table Graphic Jump Location
Table 3. Prediction Rule Test Characteristics for 30-Day Mortality in the Validation Cohort*
* 

Data are presented as % (95% CI).

Table Graphic Jump Location
Table 4. Prediction Rule Test Characteristics for 30-Day Adverse Events in the Validation Cohort*
* 

Data are presented as % (95% CI).

References

Levine, M, Gent, M, Hirsh, J, et al (1996) A comparison of low-molecular-weight heparin administered primarily at home with unfractionated heparin administered in the hospital for proximal deep-vein thrombosis.N Engl J Med334,677-681. [PubMed] [CrossRef]
 
Koopman, M, Prandoni, P, Piovella, F, et al Treatment of venous thrombosis with intravenous unfractionated heparin administered in the hospital as compared with subcutaneous low-molecular-weight heparin administered at home.N Engl J Med1996;334,682-687. [PubMed]
 
Wells, PS, Kovacs, MJ, Bormanis, J, et al Expanding eligibility for outpatient treatment of deep venous thrombosis and pulmonary embolism with low-molecular-weight heparin.Arch Intern Med1998;158,1809-1812. [PubMed]
 
Yusen, RD, Gage, BF Outpatient treatment of acute venous thromboembolic disease.Clin Chest Med2003;24,49-61. [PubMed]
 
Wicki, J, Perrier, A, Perneger, TV, et al Predicting adverse outcome in patients with acute pulmonary embolism: a risk score.Thromb Haemost2000;84,548-552. [PubMed]
 
Nendaz, MR, Bandelier, P, Aujesky, D, et al Validation of a risk score identifying patients with acute pulmonary embolism, who are at low risk of clinical adverse outcome.Thromb Haemost2004;91,1232-1236. [PubMed]
 
Aujesky, D, Obrosky, DS, Stone, RA, et al Derivation and validation of a prognostic model for pulmonary embolism.Am J Respir Crit Care Med2005;172,1041-1046. [PubMed]
 
Aujesky, D, Roy, PM, Le Manach, CP, et al Validation of a model to predict adverse outcomes in patients with pulmonary embolism.Eur Heart J2006;27,476-481. [PubMed]
 
PIOPED Investigators.. Value of ventilation/perfusion scan in acute pulmonary embolism: results of the prospective investigation of the pulmonary embolism diagnosis (PIOPED).JAMA1990;263,2753-2759. [PubMed]
 
Turkstra, F, Kiujer, PM, van Beek, E, et al Diagnostic utility of ultrasonography of leg veins in patients suspected of having pulmonary embolism.Ann Intern Med1997;126,775-781. [PubMed]
 
Remy-Jardin, M, Remy, J, Wattinne, L, et al Central pulmonary thromboembolism: diagnosis with spiral volumetric CT with the single-breath-hold-technique-comparison with pulmonary angiography.Radiology1992;185,381-387. [PubMed]
 
Prandoni, P, Cogo, A, Bernardi, E, et al A simple approach for detection of recurrent proximal vein thrombosis.Circulation1993;88,1730-1735. [PubMed]
 
Goldhaber, SZ, Visana, L, De Rosa, M Acute pulmonary embolism: clinical outcomes in the International Cooperative Pulmonary Embolism Registry (ICOPER).Lancet1999;353,1386-1389. [PubMed]
 
Zidane, M, van Hulsteijn, LH, Brenninkmeijer, BJ, et al Out of hospital treatment with subcutaneous low molecular weight heparin in patients with acute deep-vein thrombosis: a prospective study in daily practice.Haematologica2006;91,1052-1058. [PubMed]
 
Beer, JH, Burger, M, Gretener, S, et al Outpatient treatment of pulmonary embolism is feasible and safe in a substantial proportion of patients.J Thromb Haemost2003;1,186-187. [PubMed]
 
Kovacs, MJ, Anderson, D, Morrow, B, et al Outpatient treatment of pulmonary embolism with dalteparin.Thromb Haemost2000;83,209-211. [PubMed]
 
Lim, AY, Parr, DG, Stableforth, DE, et al Early discharge and home supervision of patients with pulmonary embolism treated with low-molecular weight heparin.Eur J Intern Med2003;14,89-93. [PubMed]
 
Aujesky, D, Smith, KJ, Cornuz, J, et al Cost-effectiveness of low-molecular-weight heparin for treatment of pulmonary embolism.Chest2005;128,1601-1610. [PubMed]
 
Konstantinides, S, Geibel, A, Olschewski, M, et al Importance of cardiac troponin in risk stratification of patients with acute pulmonary embolism.Circulation2002;106,1263-1268. [PubMed]
 
Douketis, JD, Leewenkamp, O, Grobara, P, et al The incidence and prognostic significance of elevated cardiac troponin in patients with submassive pulmonary embolism.J Thromb Haemost2005;3,508-513. [PubMed]
 
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    Print ISSN: 0012-3692
    Online ISSN: 1931-3543