Rationale and Objectives
The aims of this study were to retrospectively evaluate whether computed tomographic (CT) parameters were predictors of in-hospital mortality within 30 days of CT imaging and to compare CT parameters with clinical, echocardiographic, and laboratory findings in patients with acute pulmonary embolism (PE).
Materials and Methods
A total of 122 patients (61 women, 61 men; mean age, 64 ± 15 years) with CT scans positive for acute PE were reviewed. Two independent readers who were blinded to clinical outcomes scored pulmonary artery obstructions, evaluated cardiovascular measurements, and assessed qualitative findings. Reports of echocardiographic, clinical, and laboratory findings and clinical outcome were reviewed. Results were correlated with patient outcomes using Wilcoxon’s rank-sum, χ 2 , and Student’s t tests. Logistic regression analyses were performed to determine predictors of patient outcomes.
Results
Thirteen patients (11%) died related to PE within 30 days in the hospital. There were significant differences in the ratio of arterial partial pressure of oxygen to inspired fraction of oxygen and in heart rate between survivors and nonsurvivors ( P < .05). No CT or echocardiographic predictor was associated with mortality.
Conclusions
The ratio of arterial partial pressure of oxygen to inspired fraction of oxygen and heart rate strongly predicted mortality due to PE. Neither CT pulmonary angiographic variables nor echocardiography could successfully predict in-hospital mortality in patients with acute PE.
Acute pulmonary embolism (PE) is a common and potentially fatal disease, with an overall 30-day mortality rate that exceeds 10% . Although most late deaths are due to underlying disease, such as cancer, chronic lung disease, or congestive heart failure, the main cause of death within 30 days is right ventricular (RV) failure . Rapid risk stratification is paramount for identifying high-risk patients and helps select the appropriate treatment strategy. Thrombolysis , catheter intervention , or surgical embolectomy as adjuncts to anticoagulation may rapidly reverse RV failure and reduce the risk for recurrence and death. In recent years, many attempts have been made to stratify patients according to their risk for death due to acute PE. From the results of large retrospective registries and randomized trials of thrombolytic agents, clinical presentation is considered the most powerful predictor of death due to PE . However, there have been attempts to further risk-stratify patients with imaging. With the development of narrow collimation, multi–detector row computed tomographic (CT) imaging, and modern workstations for image postprocessing and analysis, CT pulmonary angiography is being recommended as the modality of choice for the assessment of patients with pulmonary emboli .
Several retrospective studies have investigated the relationships between pulmonary artery (PA) obstruction score, cardiovascular parameters, and patient outcomes . On the other hand, several reports have suggested that some clinical and laboratory parameters, such as arterial blood gas measurements and troponin T, are prognostic findings in patients with acute PE . However, conflicting conclusions are present between these studies. Furthermore, none of the existing CT studies have attempted to control for clinical presentation variables or echocardiographic and laboratory findings. Thus, the aims of our study were to retrospectively evaluate whether CT quantitative and qualitative parameters were predictors of in-hospital mortality within 30 days of CT imaging and to compare CT parameters with echocardiographic, clinical, and laboratory findings in patients with acute PE.
Materials and methods
Patient Selection
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CT Acquisition
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Image Review
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Echocardiography
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Clinical Information
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Statistical Analysis
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Results
Interreader Agreement
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Patient Demographics and Outcomes
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Table 1
Demographic Findings and Clinical Characteristics
Parameter Survivors ( n = 109) Nonsurvivors ( n = 13) Mean age (y) 63 ± 15 69 ±14 Men (%) 56 (51%) 5 (38%) Predisposing factors Age (>65 y) 70 (64%) 8 (61%) Immobilization 43 (39%) 3 (23%) Malignancy 25 (22%) 5 (38%) Surgery 15 (13%) 1 (8%) Congestive heart failure 11 (10%) 3 (23%) Obesity 12 (11%) 1 (8%) Oral contraceptive use 4 (4%) 0 (0%) Comorbidities Hypertension 35 (32%) 5 (38%) Malignancy 22 (20%) 8 (61%) Ischemic heart disease 20 (18%) 0 (0%) Diabetes 19 (17%) 1 (8%) Congestive heart failure 12 (11%) 3 (23%) Chronic obstructive pulmonary disease 11 (10%) 2 (15%) Cerebrovascular accident 11 (10%) 2 (15%) Chronic renal failure 2 (2%) 2 (15%) Chronic liver disease 1 (1%) 0 (0%) Clinical and laboratory findings HR (beats/min) 92 ± 16 103 ± 15 PaO 2 (mm Hg) 68 ± 15 62 ± 13 PaCO 2 (mm Hg) 30 ± 7 28 ± 9 Saturation (%) 93 ± 4 91 ± 3 PaO 2 /FiO 2 322 ± 84 246 ± 92 Blood pressure (mm Hg) 86 ± 11 75 ± 19 Troponin T (ng/mL) 0.09 ± 0.16 0.15 ± 0.10 Treatment Low–molecular weight heparin 104 (95%) 11 (85%) Thrombolytic agent 5 (5%) 2 (15%)
Data are expressed as mean ± standard deviation or as number (percentage).
FiO2, inspired fraction of oxygen; HR, heart rate; PaCO 2 , arterial partial pressure of carbon dioxide; PaO 2 , arterial partial pressure of oxygen.
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CT Quantitative Measurements
PA Obstruction score
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CT Cardiovascular measurements
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Table 2
Comparisons of CT Quantitative Measurements Between Survivors and Nonsurvivors
CT Parameter Survivors ( n = 109) Nonsurvivors ( n = 13)P ∗ PA obstruction index (%) 36.07 34.00 .78 RV/LV ratio 1.29 1.43 .30 PA/aorta ratio 0.84 0.89 .48 LA diameter (mm) 39.32 38.77 .89 Azygos vein diameter (mm) 8.95 9.17 .74 SVC diameter (mm) 18.85 18.83 .98
Data are expressed as means.
CT, computed tomographic; LA, left atrial; LV, left ventricular; PA, pulmonary artery; RV, right ventricular; SVC, superior vena cava.
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Table 3
Correlation Between PA Obstruction Score and CT Cardiovascular Measurements
CT Parameter Pearson’s Correlation Coefficient_P_ RV/LV ratio 0.638 <.001 PA/aorta ratio 0.359 <.001 LA diameter −0.377 <.001 Azygos vein diameter 0.424 <.001 SVC diameter 0.255 <.001
Abbreviations as in Table 2 .
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CT Qualitative findings
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Table 4
Comparison of CT Qualitative Findings Between Survivors and Nonsurvivors
CT Finding Survivors ( n = 109) Nonsurvivors ( n = 13)P ∗ Ventricular septal bowing 42 (38%) 8 ( 61%) .14 Pleural effusion 36 (33%) 7 (54%) .21 Reflux into inferior vena cava 45 (41%) 7 (54%) .55 Pulmonary infarct 28 (26%) 2 ( 15%) .51 Mosaic perfusion defect 44 (40%) 7 (54%) .38
Abbreviation as in Table 2 .
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Echocardiographic Findings
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Clinical and Laboratory Results
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Table 5
Comparisons of Clinical and Laboratory Quantitative Measurements between Survivors and Nonsurvivors
Parameter Survivors ( n = 109) Nonsurvivors ( n = 13)P ∗ Troponin T (ng/mL) 0.09 0.15 .37 PaO 2 /FiO 2 ratio 322 246 .003 PaO 2 (mm Hg) 68 62 .19 PaCO 2 (mm Hg) 30 28 .35 HR (beats/min) 92 103 .02 Blood pressure (mm Hg) 86.3 75.5 .07
Data are expressed as means value.
Abbreviations as in Table 1 .
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Discussion
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CT Parameters
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Echocardiographic Findings
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Clinical and Laboratory Findings
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Limitations
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Conclusions
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