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Original Research: Pulmonary Vascular Disease |

Validation of a Model for Identification of Patients at Intermediate to High Risk for Complications Associated With Acute Symptomatic Pulmonary EmbolismBova Score Validation FREE TO VIEW

Carolina Fernández, MD; Carlo Bova, MD; Olivier Sanchez, PhD; Paolo Prandoni, PhD; Mareike Lankeit, MD; Stavros Konstantinides, PhD; Simone Vanni, MD; Covadonga Fernández-Golfín, PhD; Roger D. Yusen, MD; David Jiménez, PhD, FCCP
Author and Funding Information

From the Respiratory Department (Drs Fernández and Jiménez) and Cardiology Department (Dr Fernández-Golfín), Ramón y Cajal Hospital, IRYCIS, Alcalá de Henares University, Madrid, Spain; Department of Medicine (Dr Bova), University Hospital of Cosenza, Cosenza, Italy; Université Paris Descartes (Dr Sanchez), Sorbonne Paris Cité, Paris, France; Division of Respiratory and Intensive Care Medicine (Dr Sanchez), Hôpital Européen Georges Pompidou, AP-HP, Paris, France; Department of Cardiovascular Sciences (Dr Prandoni), Vascular Medicine Unit, University Hospital of Padua, Padua, Italy; Center for Thrombosis and Hemostasis (Drs Lankeit and Konstantinides), University of Mainz, Mainz, Germany; Emergency Department (Dr Vanni), Azienda Ospedaliero-Universitaria Careggi, Florence, Italy; and Division of Pulmonary and Critical Care Medicine (Dr Yusen), Washington University School of Medicine, St. Louis, MO.

CORRESPONDENCE TO: David Jiménez, PhD, FCCP, Respiratory Department and Medicine Department, Ramón y Cajal Hospital, IRYCIS, Alcalá de Henares University, 28034 Madrid, Spain; e-mail: djimenez.hrc@gmail.com


FUNDING/SUPPORT: The Instituto de Salud Carlos III and NEUMOMADRID provided funding for the study [Grants FIS 2011 (PI11/00246) and NEUMOMADRID 2014].

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.


Chest. 2015;148(1):211-218. doi:10.1378/chest.14-2551
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BACKGROUND:  For patients with acute symptomatic pulmonary embolism (PE), the Bova score classifies their risk for PE-related complications within 30 days after diagnosis. The original Bova score was derived from 2,874 normotensive patients with acute PE who participated in one of six prospective PE studies.

METHODS:  We retrospectively assessed the validity of the Bova risk model in normotensive patients with acute PE diagnosed in an academic urban ED. Two clinician investigators used baseline data for the model’s four prognostic variables to stratify patients into the three Bova risk stages (I-III) for 30-day PE-related complications. Intraclass correlation coefficient (ICC) and the κ statistic were used to assess interrater variability.

RESULTS:  The Bova risk score classified the majority of the cohort of 1,083 patients into the lowest Bova risk stage (stage I, 80%; stage II, 15%; stage III, 5%), The primary end point occurred in 91 of the 1,083 patients (8.4%; 95% CI, 6.7%-10%) during the 30 days after PE diagnosis. Risk stage correlated with the PE-related complication rate (class I, 4.4%; class II, 18%; class III, 42%; ICC, 0.93 [95% CI, 0.92-0.94]; κ statistic, 0.80; P < .001), in-hospital complication rate (class I, 3.7%; class II, 15%; class III, 37%), and 30-day PE-related mortality (class I, 3.1%; class II, 6.8%; class III, 10.5%).

CONCLUSIONS:  The Bova risk score accurately stratifies normotensive patients with acute PE into stages of increasing risk of PE-related complications that occur within 30 days of PE diagnosis.

Figures in this Article

Hemodynamically stable patients at a high risk for short-term adverse pulmonary embolism (PE)-related clinical events (ie, intermediate- to high-risk group) might benefit from an escalation of therapy beyond standard anticoagulation (ie, recanalization procedures). Advocating for escalated PE therapy implies not only the weighing of therapeutic and adverse effects for a specific therapy but also the need for accurate identification of appropriate patients. Single markers of right ventricular (RV) dysfunction (eg, transthoracic echocardiography [TTE], spiral CT scan, brain natriuretic peptide testing) or myocardial injury (eg, cardiac troponin T or I testing) have an insufficient positive predictive value for PE-specific complications to drive decision-making toward recanalization procedures, and studies have suggested that they only identify an intermediate- to low-risk group of patients with PE.13 Although some observational studies have suggested that cardiac biomarkers may possess prognostic value additive to that of echocardiography,46 the findings from the recently published Pulmonary Embolism Thrombolysis Trial suggested that such a combination might not be strong enough to reliably identify patients at increased risk for PE-related complications.7

We previously devised a simple grading system for stratifying the risk of short-term PE-related complications in normotensive patients with confirmed acute symptomatic PE (ie, the Bova score).8 The score comprises four variables assessed at the time of PE diagnosis: two clinical variables (ie, heart rate, systolic BP), a laboratory biomarker (ie, cardiac troponin), and a marker of RV dysfunction (ie, RV size and function measured by echocardiography or spiral CT scan) (Table 1). In the derivation study, the Bova score stratified patients into one of three Bova risk stages (I-III), where the PE-related complication rate over 30 days after PE diagnosis increased with increasing risk stage (stage I, 4.2%; stage II, 10.8%; stage III, 29.2%).

Table Graphic Jump Location
TABLE 1 ]  Bova Score and Staging System for Risk of PE-Related Complications Within 30 Days of Acute Symptomatic PE Diagnosis

Points are assigned for the presence of each variable. The sum of the variable points produces the total point score (Bova risk score; range, 0-7). Bova risk staging increased with point totals: stage I (0-2 points), stage II (3-4 points), or stage III (> 4 points). PE = pulmonary embolism; RV = right ventricular.

We aimed to further evaluate Bova scoring and risk stratification in different patients and in a different setting from the original Bova derivation cohort. We hypothesized that the Bova score would show good reproducibility and evidence of validity for risk stratification of normotensive patients with acute PE.

Study Design

For this retrospective cohort validation and reliability assessment study, we used an ongoing registry that has prospectively gathered data from consecutively eligible patients with confirmed acute symptomatic PE since January 1, 2003. Patients in this cohort underwent enrollment through December 31, 2013. We a priori excluded those patients who contributed to the original patient-level meta-analysis that led to the development of the Bova score.4,9

Patients, Setting, and Eligibility Criteria

For the registry, we screened outpatients who presented with symptoms of acute PE to the ED of Ramón y Cajal Hospital, Madrid, Spain (Fig 1). This study required patients to have an acute symptomatic PE confirmed by objective testing and excluded patients with hemodynamic instability at presentation (defined as cardiogenic shock, systolic BP < 90 mm Hg, or need for inotropic support despite BP measurements) and those who did not successfully complete the protocol-required troponin and TTE testing. The Institutional Review Board (Ramón y Cajal Hospital, 168/2006) approved the data collection for the registry and the conduct of this study.

Figure Jump LinkFigure 1 –  Patient flow diagram for registry and validation study eligibility. PE = pulmonary embolism; TTE = transthoracic echocardiography.Grahic Jump Location
Diagnosis of PE

For confirmation of the diagnosis of PE, we required an intraluminal filling defect on PE-protocol contrast-enhanced helical chest CT scan10 or a high-probability ventilation-perfusion scan according to the criteria of the Prospective Investigation of Pulmonary Embolism Diagnosis.11 The study also considered PE to be present in patients with inconclusive ventilation/perfusion scans or normal CT scans who also had a lower-limb venous compression ultrasound showing a DVT.12 Board-certified radiologists interpreted the ventilation/perfusion and CT scans.

Cardiac Troponin I Assay

Participants had blood samples obtained from an upper-extremity vein during their evaluation at the ED. The hospital laboratory used a microparticle enzyme immunoassay (Abbott) to quantitatively measure cardiac troponin I (cTnI) levels. The analytical sensitivity for the cTnI test was 0.05 ng/mL, and it represented the lowest measurable concentration of cTnI that was distinguishable from 0. With this assay, we regarded cTnI concentrations > 0.05 ng/mL as indicating myocardial injury (ie, cTnI positive).

Transthoracic Echocardiography

The study required that patients undergo TTE within 24 h after diagnosis of PE. Trained and certified echocardiographers used a Philips ultrasound system (Philips Agilent Sonos) and a 3.5-MHz transducer. Patients underwent testing in the left lateral position. Trained and certified cardiologists interpreted each echocardiogram. The study defined echocardiographic RV dysfunction as dilatation of the right ventricle (end-diastolic diameter > 30 mm from the parasternal view or the right ventricle appearing larger than the left ventricle from the subcostal or apical view), hypokinesis of the RV free wall (any view), or peak tricuspid regurgitation velocity > 2.6 m/s from the apical or subcostal four-chamber view.9,13

Calculation of the Prediction Rule

The characteristics of each patient at the time of PE diagnosis determined his or her Bova score (Table 1).8 The sum of the points scored for each of four predictors produced a total score (ie, the Bova score). Each Bova score was converted into one of three Bova risk stages (I-III). For this study, we dichotomized the three risk stages to produce intermediate- to low-risk (stages I and II) and intermediate- to high-risk (stage III) groups.

Study Outcome Measures

For the primary end point, we used a composite outcome of PE-related complications that comprised death from PE, hemodynamic collapse, or recurrent nonfatal PE. PE was considered the cause of death if there was objective documentation or the cause was unexplained and PE could not be confidently ruled out. We assessed mortality presence, cause, and date using medical record review and proxy interviews when necessary. The study protocol defined hemodynamic collapse as systolic BP < 90 mm Hg for at least 15 min, need for catecholamine administration because of persistent arterial hypotension or shock, need for thrombolysis, need for endotracheal intubation, or need for CPR. Recurrent PE was confirmed either by the presence of a new intraluminal filling defect, by an extension of a previous filling defect on CT scan, or by a new perfusion scan defect involving ≥ 75% of a lung segment. In addition to the primary end point, the study assessed in-hospital PE-related complications and PE-related mortality as secondary end points. Blinded to Bova score and risk stage, study investigators adjudicated all study end points. Similar to the Bova score development study,8 this study assessed for the primary outcome through 30 days after the diagnosis of PE.

For reliability assessment of the Bova score and Bova risk stratification, the study assessed interobserver variability. Two physician observers (C. F. and D. J.) determined their scores while blinded to the impressions of the other scorer and to patient outcomes.

Statistical Analysis

For reporting of continuous data, we used standard descriptive statistics. For comparisons of continuous data between groups, we used unpaired two-tailed t tests. For nonnormally distributed continuous data as determined by Kolmogorov-Smirnov test, we reported the median and 25th and 75th percentiles, and we used the Mann-Whitney U test for group comparisons. For categorical data, we described baseline characteristics with counts and proportions. We used the χ2 or Fisher exact test for categorical data group comparisons.

We used Kaplan-Meier curves to show survival by risk class over time, and the log-rank test was used to assess for statistically significant differences among the risk class groups. To assess the test performance characteristics of the Bova score prediction rule stratifying patients into intermediate- to low-risk vs intermediate- to high-risk categories, we estimated sensitivity, specificity, and positive and negative predictive values. We assessed the discriminatory power of the stratified prediction rule by calculating the area under each receiver operating characteristic curve (ie, C statistic).

For the determination of interobserver variability, we relied on the intraclass correlation coefficient to compare the respective raw scores for each of the two observers. We used the κ statistic to assess interrater agreement for risk classification above and beyond chance. We interpreted κ < 0.20 as poor, 0.21 to 0.40 as fair, 0.41 to 0.60 as moderate, 0.61 to 0.80 as good; and 0.81 to 1.00 as very good.14 The 95% CIs were calculated from the binomial distribution using SPSS version 20.0 software (IBM Corporation).

Study staff screened 1,358 consecutive outpatients with acute PE for eligibility in the prospective registry. Hemodynamic instability excluded 58 patients (4.3%) from participation in this study. Of the remaining hemodynamically stable patients, the study excluded 10% (136 of 1,300) because they did not have a TTE (n = 70; 5.4%) or a troponin measurement (n = 66; 5.1%). Other reasons for exclusion were anticipated unavailability for follow-up (n = 47) and refusal to give informed consent (n = 34). The 1,083 remaining eligible patients (486 men and 597 women) were enrolled in the study (Fig 1). Overall, the Bova score classified 80% (865 of 1,083) of patients in risk stage I, 15% (161 of 1,083) in stage II, and 5% (57 of 1,083) in stage III.

To assess for enrollment bias, we compared characteristics of patients enrolled with those not enrolled in the study. The eligible patients did not differ significantly from the ineligible patients in terms of distribution of disease severity as measured by the simplified Pulmonary Embolism Severity Index (sPESI).15

We compared patient characteristics, risk scores, and outcomes for the Bova score derivation cohort and the study validation cohort. Patients in the validation cohort were older, had fewer comorbidities (eg, cancer, chronic pulmonary disease), and had more signs of clinical severity (eg, syncope, tachycardia, hypoxemia, mild hypotension [but not hemodynamically unstable]) than those in the derivation cohort (Table 2). Compared with patients in the derivation cohort, patients in the validation cohort less frequently had echocardiographic RV dysfunction or myocardial injury (Table 2), and the sPESI classified a significantly lower proportion of patients as low risk (31% [339 of 1,083] vs 36% [1,029 of 2,874]; P < .01).

Table Graphic Jump Location
TABLE 2 ]  Characteristics of Derivation and Validation Bova Risk Score Cohorts

Data are presented as No. (%) or median (25th-75th percentile). BNP = brain natriuretic peptide; sPESI = simplified Pulmonary Embolism Severity Index. See Table 1 legend for expansion of other abbreviations.

a 

Active or under treatment in the past year.

b 

In the previous month.

c 

Immobilized patients defined as nonsurgical patients who had been immobilized (ie, total bed rest with bathroom privileges) for ≥ 4 d in the month prior to PE diagnosis.

The study had complete primary outcome information for all patients at the end of the 30-day follow-up. The primary end point occurred in 91 of 1,083 patients (8.4%; 95% CI, 6.7%-10%). PE-related complications were due to PE-related death in 44 patients, hemodynamic collapse in 49 patients, and nonfatal symptomatic recurrent PE in seven patients (Table 3). Of the 87 of 1,083 patients who died during the 30-day follow-up period (8.0%; 95% CI, 6.4%-9.6%), death was considered as definitely or possibly due to fatal PE in 51% (44 of 87; 95% CI, 40%-61%), and this corresponded to a cumulative rate of definite or possible fatal PE of 4.1% (44 of 1,083; 95% CI, 2.9%-5.2%) at 30 days after PE diagnosis. Twenty-three of the 1,083 patients experienced the primary end point during hospitalization (2.1%; 95% CI, 1.3%-3.0%). In-hospital PE-related complications were due to PE-related death in 1.7% (18 of 1,083; 95% CI, 0.9%-2.4%).

Table Graphic Jump Location
TABLE 3 ]  PE-Related Complications in the Cohort of Normotensive Patients With Acute Symptomatic PE During 30 Days of Follow-up

Data are presented as No. (%). See Table 1 legend for expansion of abbreviation.

a 

Defined as PE-related mortality, hemodynamic collapse, or recurrent PE; patients may have more than one event fulfilling the definition for PE-related complications.

b 

Defined as at least one of the following: systolic BP < 90 mm Hg for at least 15 min, need for catecholamine administration because of persistent arterial hypotension or shock, need for endotracheal intubation, or need for CPR.

Cumulative incidence of 30-day PE-related complications differed substantially among Bova risk stages (stage I, 4.4% [38 of 865]; stage II, 18% [29 of 161]; stage III, 42% [24 of 57]) (Fig 2). Similarly, the risk of in-hospital PE-related complications and 30-day PE-related mortality increased with increasing Bova risk stage (Table 4). The in-hospital complication rate was 3.7% (32 of 865 patients) for stage I, 15% (24 of 161) for stage II, and 37% (21 of 57) for stage III, whereas 30-day PE-related mortality was 3.1% (27 of 865), 6.8% (11 of 161), and 10.5% (six of 57), respectively.

Figure Jump LinkFigure 2 –  Cumulative PE-related complications stratified by Bova risk stage. Log-rank test P < .001. See Figure 1 legend for expansion of abbreviation.Grahic Jump Location
Table Graphic Jump Location
TABLE 4 ]  Complication Rates During 30 Days After Diagnosis of PE Based on Bova Risk Classification

Data are presented as No. (%, 95% CI). See Table 1 legend for expansion of abbreviation.

a 

Stage I (0-2 Bova risk score points), stage II (3-4 points), stage III (> 4 points); see Table 1 for scoring schema.

When dichotomizing the Bova risk stages as intermediate to low risk (stages I and II) vs intermediate to high risk (stage III), the model had a specificity of 97% (95% CI, 95%-98%), a positive predictive value of 42% (95% CI, 29%-56%), and a positive likelihood ratio of 7.9 (95% CI, 4.9-12.8) for predicting 30-day PE-related complications (Table 5). Because this cut point was specifically chosen to identify intermediate- to high-risk patients with PE, the higher risk group in this study, the sensitivity (26%; 95% CI, 18%-37%) and negative likelihood ratio (0.8; 95% CI, 0.7-0.9) for predicting PE-related complications were low. The area under the receiver operating characteristic curve of the model was 0.74 (95% CI, 0.68-0.80), indicating good discriminatory power.

Table Graphic Jump Location
TABLE 5 ]  Test Characteristics for Predicting PE-Related Complications Among Patients at Intermediate to Low Risk (Bova Risk Stages I and II) vs Intermediate to High Risk (Bova Risk Stage III)

See Table 1 legend for expansion of abbreviation.

Regarding the Bova score interrater reliability assessment, the mean scores were similar between the two observers (observer 1, 1.4 ± 1.6; observer 2, 1.3 ± 1.5; P = .53). The Bova raw scores showed high interrater reliability (intraclass correlation coefficient, 0.93; 95% CI, 0.92-0.94). For Bova risk classification (based on Bova risk scores), the two observers agreed in 93% of the cases (1,009 of 1,083; 95% CI, 92%-95%). Bova risk classification had good interrater reliability (κ = 0.80, P < .001). Dichotomized Bova risk stages of intermediate to low risk and intermediate to high risk showed an agreement of 98% and very good interrater reliability (κ = 0.82, P < .0001).

This study of normotensive patients with acute symptomatic PE demonstrated the validity of the Bova score for accurately assessing risk for PE-related complications that occur within 30 days of PE diagnosis. The study also demonstrated good to very good interrater reliability of the four variables that produce the risk score, the risk classification, and a dichotomized version of the risk classification.

Despite modern methods for diagnosis and treatment, PE continues to have a high mortality rate.16,17 Prognostic models for patients with PE could assist with medical decision-making. For example, normotensive patients with an estimated high-risk for PE-related complications might benefit from surveillance in an intensive care setting18 or from the administration of specific advanced therapy.19

This study demonstrated the reliability of the Bova risk score and provided further evidence of its validity. Akin to the original derivation study, this validation study showed a high proportion of patients dichotomized into the intermediate- to high-risk for complications (Bova risk stage III) group that had one of the composite outcome events during 30 days of follow-up after PE diagnosis. Similar to the Bova derivation study results,8 the current study showed that the proportion of PE-related complications markedly increased with each higher Bova risk stage, ranging from 4.4% for stage I to 42% for stage III. In terms of clinical utility, Bova risk classification suggests that 95% of normotensive patients with PE do not have a high risk for PE-related complications within 30 days of diagnosis. Thus, in the majority of normotensive patients with acute symptomatic PE, the risk-benefit ratio of aggressive treatment does not appear to be warranted.

Identification of patients with PE who have a low risk for complications (ie, all-cause mortality, recurrent VTE, bleeding) would assist in determining the eligibility of patients for outpatient care or an abbreviated hospital stay. Two other clinical models, the Pulmonary Embolism Severity Index (PESI) and the sPESI, for estimating prognosis in patients with acute symptomatic PE in terms of all-cause mortality have been extensively validated.15,20 However, the PESI and sPESI were specifically designed to identify patients at low risk for mortality. Alternatively, the Bova score was developed to specifically identify patients at high risk for complications associated with PE, with the aim of identifying patients who might benefit from escalation of PE therapy (eg, transfer to the ICU for thrombolysis). Use of the PESI and sPESI to identify high-risk patients and use of the Bova score to identify low-risk patients might not be appropriate. For example, only 13% of the current study patients in the high-risk PESI classes IV and V experienced 30-day PE-related complications (data not shown). Furthermore, this study suggests that up to 6% (upper limit of 95% CI of point estimate) of patients in Bova stage I might experience PE-related complications within 30 days of diagnosis.

Recent European Society of Cardiology guidelines suggest that clinicians use a stepwise approach for risk stratification of normotensive patients with PE.18 Accordingly, the guidelines recommend that only patients in PESI classes III to V or those with an sPESI score ≥ 1 should undergo echocardiographic assessment for RV dysfunction and troponin testing. Because Bova risk stage III requires the presence of at least three of the four risk factors, which, therefore, include at least one of RV dysfunction or elevated troponin level, future studies might address whether clinicians ought to obtain Bova score variables in a stepwise fashion for the sake of conducting appropriate testing, avoiding unnecessary testing and treatments, and improving cost-effectiveness. Possibly, only patients with tachycardia or borderline low BP should proceed to further testing for cardiac biomarkers (eg, troponin) or RV imaging to identify those at intermediate to high risk for PE-related complications and to consider further escalation of therapy.

This study demonstrated high interrater reliability of Bova scoring and good interrater reliability of the Bova risk classification. For risk scoring and classification, the presence or absence of echocardiographic RV dysfunction was the main driver of disagreement. Indeed, a previous study detected only fair reproducibility of the measurement of echocardiographic RV dysfunction in normotensive patients with acute PE.21 However, dichotomization of Bova risk scores and risk stages into intermediate- to low-risk and intermediate- to high-risk groups decreased the extent of disagreement and improved the reproducibility.

The strengths of this study were enrollment of a large cohort of consecutive patients with symptomatic, objectively confirmed acute PE and detailed prospective data collection on all patients. However, some study methodological limitations may have affected the findings and interpretation of the results. Although the variables for the clinical decision rule were collected prospectively, this validation study was a retrospective analysis. In addition, this single-center study of patients presenting to an urban academic ED may limit the generalizability of the findings. However, the broad range of patients with acute symptomatic PE included in the study and the prespecification of the study selection criteria likely minimized such bias. Although the Bova score addresses the very pertinent PE-related complications, it does not address some other important issues, including bleeding and all-cause mortality. Decision-making regarding treatment interventions will need to include these and other issues and individualized patient care decisions.

In conclusion, this study demonstrates the reliability of Bova risk scoring and Bova risk classification and further validates Bova score risk stratification as a prognostic tool for normotensive patients with acute symptomatic PE undergoing evaluation in an ED. Bova risk scoring and risk classification could serve as tools for matching or comparing patient risks in future studies of PE management (eg, randomized controlled trial of thrombolytic therapy). Therefore, the Bova score has potential for clinical application both at the bedside and in clinical trials.

Author contributions: D. J. had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. C. F., C. B., P. P., R. D. Y., and D. J. contributed to the study concept and design; C. F., C. B., O. S., P. P., M. L., S. K., S. V., C. F.-G., R. D. Y., and D. J. contributed to the data acquisition, analysis, and interpretation; C. F., P. P., R. D. Y., and D. J. contributed to the drafting of the manuscript; C. F., C. B., O. S., P. P., M. L., S. K., S. V., C. F.-G., R. D. Y., and D. J. contributed to the critical revision of the manuscript for important intellectual content; and P. P., R. D. Y., and D. J. contributed to the study supervision.

Financial/nonfinancial disclosures: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Role of sponsors: The sponsors had no role in the design of the study; the collection, analysis, or interpretation of the data; the writing, review, or approval of the manuscript; or the decision to submit the manuscript for publication.

cTnI

cardiac troponin I

PE

pulmonary embolism

PESI

Pulmonary Embolism Severity Index

RV

right ventricular

sPESI

simplified Pulmonary Embolism Severity Index

TTE

transthoracic echocardiography

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Figures

Figure Jump LinkFigure 1 –  Patient flow diagram for registry and validation study eligibility. PE = pulmonary embolism; TTE = transthoracic echocardiography.Grahic Jump Location
Figure Jump LinkFigure 2 –  Cumulative PE-related complications stratified by Bova risk stage. Log-rank test P < .001. See Figure 1 legend for expansion of abbreviation.Grahic Jump Location

Tables

Table Graphic Jump Location
TABLE 1 ]  Bova Score and Staging System for Risk of PE-Related Complications Within 30 Days of Acute Symptomatic PE Diagnosis

Points are assigned for the presence of each variable. The sum of the variable points produces the total point score (Bova risk score; range, 0-7). Bova risk staging increased with point totals: stage I (0-2 points), stage II (3-4 points), or stage III (> 4 points). PE = pulmonary embolism; RV = right ventricular.

Table Graphic Jump Location
TABLE 2 ]  Characteristics of Derivation and Validation Bova Risk Score Cohorts

Data are presented as No. (%) or median (25th-75th percentile). BNP = brain natriuretic peptide; sPESI = simplified Pulmonary Embolism Severity Index. See Table 1 legend for expansion of other abbreviations.

a 

Active or under treatment in the past year.

b 

In the previous month.

c 

Immobilized patients defined as nonsurgical patients who had been immobilized (ie, total bed rest with bathroom privileges) for ≥ 4 d in the month prior to PE diagnosis.

Table Graphic Jump Location
TABLE 3 ]  PE-Related Complications in the Cohort of Normotensive Patients With Acute Symptomatic PE During 30 Days of Follow-up

Data are presented as No. (%). See Table 1 legend for expansion of abbreviation.

a 

Defined as PE-related mortality, hemodynamic collapse, or recurrent PE; patients may have more than one event fulfilling the definition for PE-related complications.

b 

Defined as at least one of the following: systolic BP < 90 mm Hg for at least 15 min, need for catecholamine administration because of persistent arterial hypotension or shock, need for endotracheal intubation, or need for CPR.

Table Graphic Jump Location
TABLE 4 ]  Complication Rates During 30 Days After Diagnosis of PE Based on Bova Risk Classification

Data are presented as No. (%, 95% CI). See Table 1 legend for expansion of abbreviation.

a 

Stage I (0-2 Bova risk score points), stage II (3-4 points), stage III (> 4 points); see Table 1 for scoring schema.

Table Graphic Jump Location
TABLE 5 ]  Test Characteristics for Predicting PE-Related Complications Among Patients at Intermediate to Low Risk (Bova Risk Stages I and II) vs Intermediate to High Risk (Bova Risk Stage III)

See Table 1 legend for expansion of abbreviation.

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