The Diagnosis of Acute Pulmonary Embolism in Patients with Chronic Obstructive Pulmonary Disease*
Barry A. Lesser; M.D., F.C.C.E; Kenneth v Leeper ]r; M.D., F.C.C.E; lbul D. Stein, M.D., F.C.C.E; Herbert A. Saltzman, M.D., F.C.C.E; james Chen, M.D.; B. Taylor Thompson, M.D., F.C.C.E; Charles A. Hales, M.D.; John Popovich Jr, M.D., F.C.C.R; Richard H. Greenspan, M.D., F.C.C.E; and]ohn G. Weg, M.D., F.C.C.R
The clinical features and noninvasive tests, including ventilation perfusion (V IQ) lung scans, were assessed in 108 patients with chronic obstructive pulmonary disease (COPD) suspected of having pulmonary embolism (PE). Twenty-one (19 percent) of 108 patients had PEe In the majority of patients, it was impossible to distinguish between patients with and without PE by clinical assessment alone. However, when a high clinical index of suspicion was present, PE was con6rmed by angiography in three of three patients, but the V/Q scan was of intermediate probability. No roentgenographic abnormalities distinguished between PE and no PEe There was no difference between the alveolar-arterial oxygen gradients in either group, nor was there evidence of a reduction in the PaCOt in patients with PE who bad prior hypercapnia. Among the 108 patients with COPD, high, intermediate, low, and normal/near normal probability scans were present in 5
percent, 60 percent, 30 percent, and 5 percent, respectively The frequency of PE in these V/Q scan categories was five (100 percent) of five, 14 (22 percent) of 65, two (6 percent) of 33, and zero (0 percent) of five, respectively. In conclusion, in the majority of patients, the VIQ scan diagnosis is usually intermediate and such patients require furtber investigational studies, including angiography. However, among the few patients who demonstrated a high probability lung scan, there was a high positive predictive value for PE effectively avoiding the need for further studies. In those patients with low probability or near normal/normal V/Q scans, the negative predictive value was not lower than the general hospital population. (Cheat 1992; 102:17-22)
The clinical diagnosis of acute pulmonary embolism (PE) in patients with chronic obstructive pulmonary disease (COPD) is often difficult because the presentation of an acute embolic event may closely mimic the symptoms of acute airway obstruction. The present study was undertaken to better define the noninvasive clinical, laboratory, roentgenographic, and lung scan characteristics of acute PE in patients withCOPD.
PE were required within 24 h of study entry. Among 931 patients whose cases were reported by the PI0 PE D investigators,· the presence of CO PD was recorded on the prospective history data form in 112 patients. Four patients, however, were subsequently excluded on the basis of normal results of pulmonary function studies, Therefore, lOS had evidence of COPD based on a clinical history, physical examination, chest roentgenogram, air trapping on ventilation scan, and/or pulmonary function studies, which were performed in 43 (40 percent) of lOB patients. The severity of airways obstruction was defined on the basis of the forced expiratory volume in 1 s (FEV.) as percent predicted. Severe, moderate, and mild airways obstruction was defined as FEV. 80 percent predicted were considered normal. However, individuals were included in the mild category with a normal FEV I when there was evidence of terminal air flow reduction or increased residual volume. Individuals in the combined category had a decreased forced vital capacity (FVC) and a decreased FEV.. Some had a measured decrease in total lung capacity. Among the 43 patients who had pulmonary function studies, the airways obstruction was defined as mild in eight (19 percent), moderate in 11 (26 percent), severe in 18 (42 percent), and combined (obstructive and restrictive) in six (14 percent). The diagnosis of PE was made by angiography in 20 patients and by autopsy in one patient. Pulmonary embolism was excluded by angiography in 73 patients and by clinical outcome analysis in 14 patients, the methods for which have been described.' Clinical investigators in 100 of lOB patients recorded their individual clinical impressions as to the likelihood of PE prior to learning the results of the ventilation/perfusion (V/Q) scans and angiography. This clinical assessment of the likelihood of acute PE was made on the basis of all available noninvasive data, with the
METHODS
Patients in this study participated in the National Heart, Lung, and Blood Institute (NHLBI) sponsored collaborative study of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOfED), the methods of which have been described in detail.' The eligible study population consisted of patients 18 years or older, in whom acute PE was a diagnostic concern. Symptoms suggestive of
*From Henry Ford Hospital, Detroit (Drs. Lesser, Leeper, Stein, and Popovich); Duke University, Durham, NC (Drs. Saltzman and Chen); Massachusetts General Hospital, Boston (Dr. Thompson); YaleUniversity, New Haven, Conn (Dr. Greenspan); and University of Michigan, Ann Arbor (Dr. Weg). Dr. Lesser is now with Grace Hospital, Detroit, and Dr. Leeper is now with the University of Tennessee, Memphis. This study was supported by contracts NOI-HR-34007, NOI-HR34008, NOI-HR-34009, and NOI-HR-340IO from the National Heart, Lung, and Blood Institute, Bethesda, Md. Manuscript received October 31; revision accepted January 2, 1992. Reprint requests: Dr. Stein, Henry Ford Hospital, 2799 mst Grand, Detroit 48202
PE = pulmonary embolism; PIOPED = Prospective Investigation of Pulmonary Embolism Diagnosis; V/Q=ventilation perfusion
CHEST I 102 I 1 I JUl'(, 1992
17
exception of the V/Q scan. The basis for arriving at these clinical impressions was intuitive clinical judgment and not any specific predetermined criteria. A clinical assessment of 80 to 100 percent probability of PE was defined as high likelihood of PE, 20 to 79 percent probability was defined as intermediate likelihood, and 0 to 19 percent was defined as low likelihood.' The chest roentgenograms of all patients with COPD were reviewed by one radiologist G.C.) and two pulmonologists (B.A.L. and H.A.S.). The roentgenograms were interpreted without knowledge of the presence or absence of PE. Roentgenographic features that were considered compatible with COPD included bullae, flattened diaphragm, increased retrosternal airspace, attenuated peripheral vessels, prominent central pulmonary arteries, increased thoracic kyphosis, widened intercostal spaces, bowing of the sternum, saber sheath trachea, and roentgenographic findings of chronic bronchitis (increased interstitial markings, peribronchial cuffing, and thickened bronchial wall).I In addition, 6ndings compatible with PE, including infiltrate, effusion, oligemia, atelectasis, volume loss, and elevated hemidiaphragm were recorded.v' The V/Q scans and pulmonary angiograms were performed and interpreted according to the protocol described in the PIOPED
Table I-Prwliaposing Facton in Patienta with COPD and Suapected Acute Pulmonary Emboliam*
StatisticalMethods A Xl test with Yates· correction was used to compare the prevalence and distributions of the clinical features. Bonferronfs correction was used when comparing the frequency of characteristics in three groups, a probability of 0.01 being required for a difference to be considered significant. Because of the large number of comparisons, p values may suggest an exaggerated significance. Comparisons of continuous variable means were made with either a paired or unpaired Student's t test. Analyses of data were performed at Henry Ford Hospital using a data tape provided by the Data and Coordinating Center. RESULTS
The predisposing risk factors are shown in Table 1. Immobilization and surgery were the most common risk factors. However, there was no significant difference in the incidence of these predisposing risk factors in patients with and without PE. The frequency of various symptoms was similar among patients with and without PE (Table 2). Regarding physical signs, rales among patients with COPD tended to be more frequent in patients with PE, 17 (81 percent) of 21 vs 46 (53 percent) of 87 (p
Barry A. Lesser; M.D., F.C.C.E; Kenneth v Leeper ]r; M.D., F.C.C.E; lbul D. Stein, M.D., F.C.C.E; Herbert A. Saltzman, M.D., F.C.C.E; james Chen, M.D.; B. Taylor Thompson, M.D., F.C.C.E; Charles A. Hales, M.D.; John Popovich Jr, M.D., F.C.C.R; Richard H. Greenspan, M.D., F.C.C.E; and]ohn G. Weg, M.D., F.C.C.R
The clinical features and noninvasive tests, including ventilation perfusion (V IQ) lung scans, were assessed in 108 patients with chronic obstructive pulmonary disease (COPD) suspected of having pulmonary embolism (PE). Twenty-one (19 percent) of 108 patients had PEe In the majority of patients, it was impossible to distinguish between patients with and without PE by clinical assessment alone. However, when a high clinical index of suspicion was present, PE was con6rmed by angiography in three of three patients, but the V/Q scan was of intermediate probability. No roentgenographic abnormalities distinguished between PE and no PEe There was no difference between the alveolar-arterial oxygen gradients in either group, nor was there evidence of a reduction in the PaCOt in patients with PE who bad prior hypercapnia. Among the 108 patients with COPD, high, intermediate, low, and normal/near normal probability scans were present in 5
percent, 60 percent, 30 percent, and 5 percent, respectively The frequency of PE in these V/Q scan categories was five (100 percent) of five, 14 (22 percent) of 65, two (6 percent) of 33, and zero (0 percent) of five, respectively. In conclusion, in the majority of patients, the VIQ scan diagnosis is usually intermediate and such patients require furtber investigational studies, including angiography. However, among the few patients who demonstrated a high probability lung scan, there was a high positive predictive value for PE effectively avoiding the need for further studies. In those patients with low probability or near normal/normal V/Q scans, the negative predictive value was not lower than the general hospital population. (Cheat 1992; 102:17-22)
The clinical diagnosis of acute pulmonary embolism (PE) in patients with chronic obstructive pulmonary disease (COPD) is often difficult because the presentation of an acute embolic event may closely mimic the symptoms of acute airway obstruction. The present study was undertaken to better define the noninvasive clinical, laboratory, roentgenographic, and lung scan characteristics of acute PE in patients withCOPD.
PE were required within 24 h of study entry. Among 931 patients whose cases were reported by the PI0 PE D investigators,· the presence of CO PD was recorded on the prospective history data form in 112 patients. Four patients, however, were subsequently excluded on the basis of normal results of pulmonary function studies, Therefore, lOS had evidence of COPD based on a clinical history, physical examination, chest roentgenogram, air trapping on ventilation scan, and/or pulmonary function studies, which were performed in 43 (40 percent) of lOB patients. The severity of airways obstruction was defined on the basis of the forced expiratory volume in 1 s (FEV.) as percent predicted. Severe, moderate, and mild airways obstruction was defined as FEV. 80 percent predicted were considered normal. However, individuals were included in the mild category with a normal FEV I when there was evidence of terminal air flow reduction or increased residual volume. Individuals in the combined category had a decreased forced vital capacity (FVC) and a decreased FEV.. Some had a measured decrease in total lung capacity. Among the 43 patients who had pulmonary function studies, the airways obstruction was defined as mild in eight (19 percent), moderate in 11 (26 percent), severe in 18 (42 percent), and combined (obstructive and restrictive) in six (14 percent). The diagnosis of PE was made by angiography in 20 patients and by autopsy in one patient. Pulmonary embolism was excluded by angiography in 73 patients and by clinical outcome analysis in 14 patients, the methods for which have been described.' Clinical investigators in 100 of lOB patients recorded their individual clinical impressions as to the likelihood of PE prior to learning the results of the ventilation/perfusion (V/Q) scans and angiography. This clinical assessment of the likelihood of acute PE was made on the basis of all available noninvasive data, with the
METHODS
Patients in this study participated in the National Heart, Lung, and Blood Institute (NHLBI) sponsored collaborative study of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOfED), the methods of which have been described in detail.' The eligible study population consisted of patients 18 years or older, in whom acute PE was a diagnostic concern. Symptoms suggestive of
*From Henry Ford Hospital, Detroit (Drs. Lesser, Leeper, Stein, and Popovich); Duke University, Durham, NC (Drs. Saltzman and Chen); Massachusetts General Hospital, Boston (Dr. Thompson); YaleUniversity, New Haven, Conn (Dr. Greenspan); and University of Michigan, Ann Arbor (Dr. Weg). Dr. Lesser is now with Grace Hospital, Detroit, and Dr. Leeper is now with the University of Tennessee, Memphis. This study was supported by contracts NOI-HR-34007, NOI-HR34008, NOI-HR-34009, and NOI-HR-340IO from the National Heart, Lung, and Blood Institute, Bethesda, Md. Manuscript received October 31; revision accepted January 2, 1992. Reprint requests: Dr. Stein, Henry Ford Hospital, 2799 mst Grand, Detroit 48202
PE = pulmonary embolism; PIOPED = Prospective Investigation of Pulmonary Embolism Diagnosis; V/Q=ventilation perfusion
CHEST I 102 I 1 I JUl'(, 1992
17
exception of the V/Q scan. The basis for arriving at these clinical impressions was intuitive clinical judgment and not any specific predetermined criteria. A clinical assessment of 80 to 100 percent probability of PE was defined as high likelihood of PE, 20 to 79 percent probability was defined as intermediate likelihood, and 0 to 19 percent was defined as low likelihood.' The chest roentgenograms of all patients with COPD were reviewed by one radiologist G.C.) and two pulmonologists (B.A.L. and H.A.S.). The roentgenograms were interpreted without knowledge of the presence or absence of PE. Roentgenographic features that were considered compatible with COPD included bullae, flattened diaphragm, increased retrosternal airspace, attenuated peripheral vessels, prominent central pulmonary arteries, increased thoracic kyphosis, widened intercostal spaces, bowing of the sternum, saber sheath trachea, and roentgenographic findings of chronic bronchitis (increased interstitial markings, peribronchial cuffing, and thickened bronchial wall).I In addition, 6ndings compatible with PE, including infiltrate, effusion, oligemia, atelectasis, volume loss, and elevated hemidiaphragm were recorded.v' The V/Q scans and pulmonary angiograms were performed and interpreted according to the protocol described in the PIOPED
Table I-Prwliaposing Facton in Patienta with COPD and Suapected Acute Pulmonary Emboliam*
StatisticalMethods A Xl test with Yates· correction was used to compare the prevalence and distributions of the clinical features. Bonferronfs correction was used when comparing the frequency of characteristics in three groups, a probability of 0.01 being required for a difference to be considered significant. Because of the large number of comparisons, p values may suggest an exaggerated significance. Comparisons of continuous variable means were made with either a paired or unpaired Student's t test. Analyses of data were performed at Henry Ford Hospital using a data tape provided by the Data and Coordinating Center. RESULTS
The predisposing risk factors are shown in Table 1. Immobilization and surgery were the most common risk factors. However, there was no significant difference in the incidence of these predisposing risk factors in patients with and without PE. The frequency of various symptoms was similar among patients with and without PE (Table 2). Regarding physical signs, rales among patients with COPD tended to be more frequent in patients with PE, 17 (81 percent) of 21 vs 46 (53 percent) of 87 (p
