A simple diagnostic strategy in hospitalized patients with clinically suspected pulmonary embolism

OBJECTIVES: Diagnostic strategies in patients with suspected pulmonary embolism have been extensively studied in outpatients; their value in hospitalized patients has not been well established. Our aim was to determine the safety and clinical utility of a simple diagnostic strategy in hospitalized patients with suspected pulmonary embolism. DESIGN: Prospective management study. SETTING: Twelve teaching hospitals (five academic, seven general hospitals). SUBJECT: A total of 605 hospitalized patients with clinically suspected pulmonary embolism. All patients completed the study. INTERVENTIONS: First the clinical decision rule (CDR)-score was calculated. An unlikely CDR-score in combination with a normal D-dimer excluded pulmonary embolism. All other patients underwent helical computed tomography (CT). CT either diagnosed or excluded pulmonary embolism, in which case anticoagulants were started or withheld. All patients were instructed to report symptoms of venous thrombosis. Objective tests were performed to confirm venous thromboembolism. The primary outcome was the incidence of symptomatic venous thrombosis during 3-month follow-up. RESULTS: The combination of an unlikely CDR-score and a normal D-dimer excluded pulmonary embolism in 60 patients (10% of all patients); no venous thromboembolic event occurred during follow-up (0%; 95% CI 0-6.7%). CT excluded pulmonary embolism in 380 patients; during follow-up venous thromboembolism occurred in five patients (1.4%; 95% CI 0.4-3.1%). CONCLUSIONS: An unlikely CDR-score in combination with a normal D-dimer appears to exclude pulmonary embolism safely in hospitalized patients. Before clinical implementation it is important this safety is confirmed by others. CT testing was obviated in only 10% of patients. CT can safely exclude pulmonary embolism in hospitalized patients.     

A noninvasive approach for the treatment of patients with suspected pulmonary embolism

The diagnosis of pulmonary embolism is challenging because the signs and symptoms are nonspecific, the findings on ventilation-perfusion lung scans are often nondiagnostic, and pulmonary angiography, although definitive, is not always available. We previously reported that serial non-invasive leg testing provided a practical, noninvasive alternative to pulmonary angiography in patients who had nondiagnostic lung scans and adequate cardiorespiratory reserve. In this prospective cohort study of 1564 patients with suspected pulmonary embolism, ventilation-perfusion lung scanning and serial impedance plethysmography were used to objectively assess prognosis. Only 12 of 627 patients (1.9%) with nondiagnostic lung scans but normal serial leg testing results who were not given anticoagulants had venous thromboembolism during long-term follow-up. Noninvasive serial leg testing can avoid the need for pulmonary angiography for the majority of patients, identify those with proximal vein thrombosis who require anticoagulant treatment, and avert treatment and further investigation of patients who have adequate cardiorespiratory reserve.Presented in part at the Episcopal Hospital Fall Symposium, Philadelphia, Pennsylvania.     

Integrated diagnostic approach to suspected deep vein thrombosis and pulmonary embolism

Diagnosing deep vein thrombosis and pulmonary embolism has become definitely easier and more reliable over the past fifteen years, especially thanks the development of lower limbs venous compression ultrasonography and fibrin D-Dimer measurement. These tests allowed reducing the requirement for venography and pulmonary angiography to a small minority of patients. Simultaneously, ventilation/perfusion lung scan criteria have been standardized, and the performance of spiral computed tomography has been analyzed in an appropriate way. New sequential, mainly noninvasive strategies could be developed that proved to be safe in large-scale prospective cohort studies with prolonged follow-up. They should now be implemented in daily practice according to cost-effectiveness analyses as well as local facilities and expertise.     

The value of echocardiography in the diagnostic work-up of patients with suspected acute pulmonary embolism

Summary Echocardiography can be used as a differential diagnostic procedure in the diagnostic workup of patients with clinically suspected pulmonary embolism. If RV pressure overload is ruled out in those patients, mortality from thrombembolism seems to be low irrespective of whether pulmonary embolism is present or absent. If, on the other hand, RV pressure overload is present, the prognosis is worse and is dependent on the presence of arterial hypotension at presentation and a patent foramen ovale. Clinicians no longer insist on definite confirmation of pulmonary embolism by nuclear imaging studies or pulmonary angiography especially if the patient is clinically unstable at presentation. It is, thus, evident that echocardiography has gained an important diagnostic position for the management of patients with suspected pulmonary embolism.     

Optimization of the diagnostic management of clinically suspected pulmonary embolism in hospitalized patients

Identical diagnostic algorithms for suspected pulmonary embolism (PE) are used for hospitalized patients and outpatients, while D‐dimer levels, risk factors and pre‐test probability for PE differ, and the percentage of patients managed without computerized tomography pulmonary angiography (CTPA) is lower in hospitalized patients. We aimed to improve the efficiency of the diagnostic algorithm by increasing the threshold of the D‐dimer, the threshold of the Wells rule and by adjustments of the Wells rule. Six‐hundred and twenty‐four hospitalized patients from two previously performed management studies with a PE prevalence of 26% were studied. Adjustments were considered to be safe when the failure rate remained <2%. By applying standard management, 8% (49/624) were managed without CTPA with a failure rate of 0·0% (0/49; 95% confidence interval [CI] 0·0–7·3), and it was 1·7% (8/465; 95%CI 0·8–3·4) for all patients in whom PE was excluded at baseline. All evaluated adjustments resulted in an increase of the failure rate with very small improvements of the efficiency. Given these potentially small improvements and the increasing complexity of clinical practice if adjusted diagnostic algorithms for specific patient categories were introduced, we do not recommend further evaluation of any of the adjustments; we recommend that the standard diagnostic algorithm should continue to be applied.     

Triage patients with suspected pulmonary embolism in the emergency department using a portable ultrasound device

The diagnosis of pulmonary embolism (PE) is difficult, despite validated diagnostic models. We sought to determine the value of a portable ultrasound device for triage of patients with suspected PE referred to the emergency department, using simplified echo criteria. We prospectively studied 103 consecutive patients with suspected PE, referred to our emergency department. After D-dimer screening, 76 patients were prospectively enrolled in this ultrasound study and underwent helical chest tomography, transthoracic echocardiography, and venous ultrasonography. Among patients with PE (n = 31), a right ventricular dilation was detected in 17 patients (55%), a direct visualization of clot in the lower limbs was present in 18 patients (58%), and 8 patients (26%) had both right ventricular dilation and deep venous thrombosis. The sensitivity and specificity of a combined ultrasound strategy using echocardiography and venous ultrasonography were respectively 87% (95% confidence interval 74% to 96%), and 69% (95% confidence interval 53% to 82%). The sensitivity of this combined strategy was significantly improved as compared to venous ultrasonography alone (P = 0.01) or echocardiography alone (P = 0.005). In patients with dyspnea or with high clinical probability of PE, this combined strategy was particularly relevant with high sensitivities (respectively 94% and 100%). Echocardiography combined with venous ultrasonography using a portable ultrasound device is a reliable method for screening patients with suspected PE referred to an emergency department, especially in patients with dyspnea or with high clinical probability.     

Trends in the use of diagnostic imaging in patients hospitalized with acute pulmonary embolism

From 1979 to 2001, the proportion of imaging tests by computed tomography (CT), ventilation perfusion (VQ) lung scan, pulmonary angiography, and venous ultrasound was assessed in patients with pulmonary embolism (PE) from the National Hospital Discharge Survey. By 2001, there was a higher proportion of imaging tests with CT than VQ scans (36% vs 32%). Even so, in the United States, a large proportion of patients continued to have VQ scans.     

A survey of the diagnostic and therapeutic management of patients with suspected pulmonary embolism in the Netherlands

Background: Pulmonary embolism (PE) remains a complex diagnostic problem. Many diagnostic modalities are available. Several published guidelines have failed to yield a uniform approach. We have assessed the current diagnostic and therapeutic management of patients with clinically suspected PE in the Netherlands.Methods: A questionnaire was sent to internists and pulmonologists, who were then asked to detail their diagnostic and therapeutic management in their last patient seen with suspected PE.Results: 1571 questionnaires were sent out (response rate 64%). 95% of the patients with suspected PE underwent a perfusion scan (in 91% within 24 h). 1.6% of the respondents had no available perfusion scan facility. Of those who underwent a perfusion scan, 62% had a ventilation scan (66% with segmental defects, 80% with subsegmental defects, 27% with a normal perfusion scan). Tests for deep vein thrombosis were performed in 58% of the patients and pulmonary angiography was carried out in 6.1%. Anticoagulant treatment was instituted in 73.2% of all patients.Conclusions: The perfusion lung scan is appropriately used as the initial step in the diagnostic workup of patients with suspected PE. Ventilation scanning is overused in patients with subsegmental perfusion defects and normal scan results, whereas it is underused in patients with segmental defects. Additional ventilation scan results had a limited influence on treatment decisions. There is still considerable overtreatment of patients with suspected PE.     

The effect of helical computed tomography on diagnostic and treatment strategies in patients with suspected pulmonary embolism

BACKGROUND: Helical computed tomography (CT) has been proposed as a first-line test for the diagnosis of pulmonary embolism. How the test affects the diagnostic evaluation of patients with suspected pulmonary embolism is unknown. METHODS: We examined a cohort of 360 patients evaluated for pulmonary embolism at a teaching hospital in the 4 years following the introduction of the helical CT scan. We collected patient demographic and clinical data to calculate the pretest likelihood of pulmonary embolism; we then read the test results and determined rates of further testing and treatment for pulmonary embolism. RESULTS: After the helical CT scan became available, the number of patients referred for pulmonary embolism testing increased markedly from 170 to 624 total evaluations during 1997 to 2000 (P <0.01). This rise was due to increased use of the helical CT scan (9% to 83% of evaluations, P <0.01) as the use of ventilation-perfusion scanning (79% to 17%, P = 0.03) and pulmonary angiography (12% to <1%, P <0.01) fell. There was no change in the pre-test likelihood of disease over time, but the percentage of scans that were positive for pulmonary embolism rose (14% to 32%, P =0.02). Clinicians treated all patients who had a positive CT scan, but became less likely over time to order further testing for patients who had a negative scan (30% to 12%, P = 0.02). CONCLUSION: At this academic medical center, introduction of the helical CT scan had a profound effect on the evaluation of pulmonary embolism, resulting in more frequent use of the CT scan, and more frequent diagnosis and treatment of pulmonary embolism, despite no change in the pretest probability of disease. Future studies should confirm our findings and determine whether increased detection of pulmonary emboli results in improved outcomes.     

Diagnostic accuracy of focused cardiac and venous ultrasound examinations in patients with shock and suspected pulmonary embolism

Evaluating the diagnostic performance of focused cardiac ultrasound (US) alone and combination with venous US in patients with shock and suspected pulmonary embolism (PE). Consecutive adult patients with shock and suspected PE, presenting to two Italian emergency departments, were included. Patients underwent cardiac and venous US at presentation with the aim of detecting right ventricular (RV) dilatation and proximal deep venous thrombosis (DVT). Final diagnosis of PE was based on a second level diagnostic test or autopsy. Among the 105 patients included in the study, 43 (40.9%) had a final diagnosis of PE. Forty-seven (44.8%) patients showed RV dilatation and 27 (25.7%) DVT. Sensitivity and specificity of cardiac US were 91% (95% CI 80–97%) and 87% (95% CI 80–91%), respectively. Venous US showed a lower sensitivity (56%, 95% CI 45–60%) but higher specificity (95%, 95% CI 88–99%) than cardiac US (both p < 0.05). When cardiac and venous US were both positive (22 out of 105 patients, 21%) the specificity increased to 100% (p < 0.01 vs cardiac US), whereas when at least one was positive (54 out of 105 patients, 51%) the sensitivity increased to 95% (p = 0.06 vs cardiac US). Focused cardiac US showed good but not optimal sensitivity and specificity for the diagnosis of PE in patients presenting with shock. Venous US significantly increased specificity of cardiac US, and the diagnosis of PE can be certain when both tests are positive or reasonably excluded when negative.     

Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer.

BACKGROUND: The limitations of the current diagnostic standard, ventilation-perfusion lung scanning, complicate the management of patients with suspected pulmonary embolism. We previously demonstrated that determining the pretest probability can assist with management and that the high negative predictive value of certain D -dimer assays may simplify the diagnostic process. OBJECTIVE: To determine the safety of using a simple clinical model combined with D -dimer assay to manage patients presenting to the emergency department with suspected pulmonary embolism. DESIGN: Prospective cohort study. SETTING: Emergency departments at four tertiary care hospitals in Canada. PATIENTS: 930 consecutive patients with suspected pulmonary embolism. INTERVENTIONS: Physicians first used a clinical model to determine patients' pretest probability of pulmonary embolism and then performed a D -dimer test. Patients with low pretest probability and a negative D -dimer result had no further tests and were considered to have a diagnosis of pulmonary embolism excluded. All other patients underwent ventilation-perfusion lung scanning. If the scan was nondiagnostic, bilateral deep venous ultrasonography was done. Whether further testing (by serial ultrasonography or angiography) was done depended on the patients' pretest probability and the lung scanning results. MEASUREMENTS: Patients received a diagnosis of pulmonary embolism if they had a high-probability ventilation-perfusion scan, an abnormal result on ultrasonography or pulmonary angiography, or a venous thromboembolic event during follow-up. Patients for whom the diagnosis was considered excluded were followed up for 3 months for the development of thromboembolic events. RESULTS: The pretest probability of pulmonary embolism was low, moderate, and high in 527, 339, and 64 patients (1.3%, 16.2%, and 37.5% had pulmonary embolism), respectively. Of 849 patients in whom a diagnosis of pulmonary-embolism had initially been excluded, 5 (0.6% [95% CI, 0.2% to 1.4%]) developed pulmonary embolism or deep venous thrombosis during follow-up. However, 4 of these patients had not undergone the proper diagnostic testing protocol. In 7 of the patients who received a diagnosis of pulmonary embolism, the physician had performed more diagnostic tests than were called for by the algorithm. In 759 of the 849 patients in whom pulmonary embolism was not found on initial evaluation, the diagnostic protocol was followed correctly. Only 1 (0.1% [CI, 0.0% to 0.7%]) of these 759 patients developed thromboembolic events during follow-up. Of the 437 patients with a negative D -dimer result and low clinical probability, only 1 developed pulmonary embolism during follow-up; thus, the negative predictive value for the combined strategy of using the clinical model with D -dimer testing in these patients was 99.5% (CI, 99.1% to 100%). CONCLUSION: Managing patients for suspected pulmonary embolism on the basis of pretest probability and D -dimer result is safe and decreases the need for diagnostic imaging.     

Contrast ultrasound perfusion imaging of lower extremities in peripheral arterial disease: a novel diagnostic method.

AIMS: The purpose of this study was to establish contrast-enhanced ultrasound perfusion imaging (CUPI) of the lower extremities as a novel non-invasive diagnostic tool for patients with peripheral arterial disease (PAD). METHODS AND RESULTS: Ultrasound contrast agent (SonoVue) was injected into a peripheral vein of 16 control subjects and 16 PAD patients and its appearance in the calf muscle was detected by low-energy harmonic ultrasound. Analysis of the wash-in curves revealed that PAD patients had a significantly longer time to peak intensity (TTP), i.e. duration of maximum contrast perfusion [37 s (19-79 s) in control subjects vs. 56 s (32-104 s) in PAD patients at rest, age-adjusted P=0.002]. Exercise stress test of the calf muscle resulted in a decrease of the TTP, maintaining the significant difference in TTP between the groups [19 s (8-37 s) in control subjects vs. 32 s (18-48 s) in PAD patients after exercise, age-adjusted P=0.004]. Neither ankle-brachial index and TTP nor age and TTP showed a significant correlation. CONCLUSION: CUPI reflects the regional blood circulation of the calf muscle. In this pilot study, PAD patients show a significantly longer TTP than control subjects. The clinical relevance of CUPI is topic of ongoing studies.     

Frequency of pulmonary embolism in patients with low-probability lung scan and negative lower extremity venous ultrasound

STUDY OBJECTIVES: To define the prevalence of pulmonary embolism (PE) in patients who are undergoing pulmonary arteriography because of a high clinical suspicion for PE but who have had a low-probability lung scan and a negative lower extremity venous ultrasound examination. DESIGN: A retrospective review of the medical records of 365 consecutive patients who underwent pulmonary arteriograms for suspected PE was undertaken. RESULTS: Of the 365 pulmonary arteriograms, 62 were performed in patients with suspected PEs despite a low-probability lung scan and a negative lower extremity venous ultrasound examination. In the latter group, five patients (8%; 95% confidence interval, 2.7% to 18%) had PEs revealed on the arteriogram. CONCLUSIONS: In patients whose presentation provokes a high clinical suspicion for PE despite having had a low-probability lung scan, a negative lower extremity venous ultrasound examination is insufficient to preclude proceeding to pulmonary angiography.