Clinical Recognition of Pulmonary Embolism: Problem of Unrecognized and Asymptomatic Cases

doi:10.4065/73.9.873

Mayo Clinic Proceedings

Volume 73, Issue 9, September 1998, Pages 873-879

https://doi.org/10.4065/73.9.873 Get rights and content

Dyspnea, pleuritic chest pain, and tachypnea are widely appreciated as common initial features of pulmonary embolism (PE). This knowledge is derived primarily from prospective studies evaluating diagnostic tests or therapeutic interventions in which the study patients are suspected to have PE based on their initial symptoms. Autopsy studies, however, continue to show that most cases of fatal PE are unrecognized and undiagnosed. Data from studies screening for PE in patients with deep venous thrombosis and in postoperative patients suggest that many patients with PE are asymptomatic and that PE is unrecognized. We believe that the current concepts regarding the initial clinical features of PE are too narrow and biased toward symptomatic cases. High clinical suspicion may be insufficient in recognizing PE. Herein we summarize the available data and explore the implications for clinical practice.

Section snippets

PROSPECTIVE DIAGNOSTIC AND TREATMENT STUDIES OF PE

Most of our inferences regarding the clinical features of acute PE are based on data from large prospective studies evaluating the diagnostic accuracy of ventilation-perfusion lung scans and the therapeutic efficacy of thrombolytic agents.11, 12, 15, 16, 17, 18, 19, 20 The frequency of the most common symptoms and signs encountered in patients in whom PE is eventually proved by pulmonary angiography is summarized in Table 1. Common initial symptoms include dyspnea, pleuritic chest pain, and

AUTOPSY STUDIES OF PE

In routine autopsies of adult patients, grossly recognizable emboli are found in 1.5 to 30% of cases.7, 21, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36 With careful dissection and microscopic examination, the percentage of autopsy cases showing recent or old thromboemboli increases to 51 to 69%.37, 38, 39 PE is the primary cause of death in 3 to 10% of all hospital deaths and is a contributing cause in another 10%.7, 24, 26, 27, 28, 29, 31, 33, 34, 40, 41, 42, 43, 44, 45, 46, 47 Thus, PE

CHRONIC THROMBOEMBOLIC PULMONARY HYPERTENSION

In patients who survive an episode of PE, the prognosis is generally good when appropriate therapy is administered.3, 23, 49, 52, 53 The pulmonary emboli primarily resolve, and residual respiratory symptoms are uncommon.3, 54 Long-term mortality is related to underlying diseases such as cancer, congestive heart failure, infections, or chronic lung disease.52, 53 Some long-term survivors have development of chronic thromboembolic pulmonary hypertension related to inadequate resolution of large

SCREENING FOR PE IN PATIENTS WITH DVT

Although prospective studies evaluating diagnostic tests and therapeutic agents for PE have suggested that almost all patients with PE are symptomatic, a different perspective is provided by screening studies of patients at risk for PE. Monreal and colleagues⁵⁸ performed ventilationperfusion lung scanning in 434 consecutive patients with venographic ally proven DVT; in 164 (38%), scans showed high probability for PE. Of those 164 patients, 54% had symptoms or signs consistent with PE, and 46%

SCREENING FOR PE IN POSTOPERATIVE PATIENTS

Surgical patients, particularly those undergoing an orthopedic operation, are at high risk for venous thromboembolism.⁷¹ During the past 30 years, multiple screening studies have documented the incidence of DVT and PE in high-risk patients. Pertinent studies regarding the occurrenee of asymptomatic PE are summarized in Table 4.50, 51, 68, 69, 70, 72 In the postoperative patient, asymptomatic PE occurred 4 times as often as did symptomatic PE. For example, Rissanen and colleagues⁷² used

CONCLUSION

The evidence summarized herein suggests that many episodes of PE are unrecognized and undiagnosed, especially in postoperative patients. Some patients with undiagnosed and untreated PE suffer unexpected death or chronic thromboembolic pulmonary hypertension (Fig. 1); however, it is likely that many of these overlooked cases have no recognizable clinical sequelae and are never identified. Although most clinicians realize that the common initial features of PE including dyspnea, pleuritic chest

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Incidental pulmonary embolisms (IPEs) are common in cancer patients. Examining the characteristics and outcomes of IPEs in cancer patients can help to ensure proper management, promoting better outcomes. To determine the clinical characteristics, management, and outcomes of IPEs for cancer patients, we conducted a 1:2 ratio case-control study and identified all consecutive patients with IPE who visited the emergency department at The University of Texas MD Anderson Cancer Center between 1 January 2006 and 1 January 2016. Each IPE case was matched with 2 controls using a propensity score obtained using logistic regression for IPE status with other factors affecting overall survival. A total of 904 confirmed cases were included in the analysis. IPE frequently occurred during the first year after cancer diagnosis (odds ratio [OR], 2.79; 95% confidence interval [95% CI], 2.37-3.29; P < .001). Patients receiving cytotoxic chemotherapy had a nearly threefold greater risk of developing IPE (OR, 2.87; 95% CI, 2.42-3.40; P < .001). In-hospital mortality was 1.9%. The 7- and 30-day mortality rates among the cases were 1.8% and 9.9%, respectively, which was significantly higher than in the control groups: 0.2% and 3.1%, respectively (P < .001). IPE was associated with reduced overall survival (hazard ratio [HR], 1.93; 95% CI, 1.74-2.14; P < .001). Concurrent incidental venous thromboembolism was identified in 189 of the patients (20.9%) and was also associated with reduced overall survival (HR, 1.65; 95% CI, 1.21-2.25; P = .001). Our results show that IPE events are associated with poor outcomes in cancer patients. Proper management plans similar to those of symptomatic pulmonary embolisms are essential.
Routine deep vein thrombosis screening after lung transplantation: Incidence and risk factors
2020, Journal of Thoracic and Cardiovascular Surgery
Citation Excerpt :
The presence of DVT (asymptomatic or otherwise) early in a patient who has undergone LTx is associated with significant morbidity and mortality, as shown by our significantly different survival curves and median survival times. Additionally, there is a strong correlation between asymptomatic DVT occurrences and symptomatic venous thromboembolism episodes even with modern thromboprophylaxis15,16 and early complications have been associated with long-term morbidity and mortality.17 We found that universal DVT screening (in our case, at day 0 and day 14) significantly increased the rate of DVT detection and there was a trend toward screening resulting in improved 1-year survival.
Deep vein thrombosis (DVT) remains a common complication following lung transplantation despite universal routine DVT screening. Moreover, many of the previously reported risk factors are incompletely defined. We sought to explore the influence of DVT screening and to more definitively assess predisposing risk factors.
A single-institution, retrospective, cohort study of 1141 patients undergoing lung transplantation from January 1, 2005, to December 31, 2014, was performed evaluating for the rate of DVT. Patients were given prophylactic subcutaneous heparin postoperatively. DVT events were noted if they occurred before 90 days after transplant. We compared DVT rates before and after 2008 when universal screening was implemented. We also evaluated the timing of DVT event and location (above the knee vs below the knee). DVTs were treated with standard anticoagulation therapy or an inferior cava filter when patients were unable to tolerate anticoagulation treatment. Univariable and multivariable models were used to identify risk factors for occurrence. A propensity match was performed to match groups across the eras, and a Cox regression was performed to identify differences in 1-year survival trajectory between cohorts.
The rates of DVT before and after routine screening were 8.8% (36 DVT out of 412 transplants) and 17.3% (126 out of 729 transplants), respectively. These 2 rates were significantly different (P < .01); moreover, the observed DVT incidence per year was not significantly different across the 6 years after universal DVT screening was implemented (P > .90 for all comparisons). Observed DVT incidence at day 0 and day 14 were 3.8% and 3.8%, respectively, for the cohort before DVT protocols were established. Observed DVT incidence for the cohort after protocols were established at the same time points was 8.7% and 3.7%, respectively. Univariable analysis revealed that significant factors associated with a DVT include hypercholesterolemia (odds ratio [OR], 6.90; 95% confidence interval [CI], 1.82-26.13; P < .01), the number of days in the intensive care unit (OR, 1.03; 95% CI, 1.00-1.01; P < .01), and the length of stay in the hospital (OR, 1.01; 95% CI, 1.01-1.02; P < .01), whereas having quit smoking (vs never smoked) was associated with a decrease in DVT development (OR, 0.50; 95% CI, 0.33-0.75; P < .01). Multivariable analysis revealed 2 significant variables: hypercholesterolemia (OR, 8.13; 95% CI, 1.22-54.37; P = .03) and length of stay (OR, 1.03; 95% CI, 1.01-1.05; P < .01). There was a trend for better 1-year survival in the post-2008 era (Exp[β], 1.49; P = .09).
The rate of DVT diagnosis significantly increased after universal DVT screening was implemented. Furthermore, those patients undergoing lung transplantation with extended length of stay and hypercholesterolemia were prone to increased rates of DVT. There was a trend toward better 1-year survival in DVT-screened patients, suggesting DVT screening may result in beneficial outcomes.
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Endovascular aortic repair (EVAR) is associated with an increased risk of pulmonary embolism, which is often clinically silent and therefore difficult to recognise. The aim was to investigate the incidence of pulmonary embolism after EVAR using routinely performed pre- and post-operative aortic computed tomography angiography (CTA), and the association between pulmonary embolism and mortality.
This single centre retrospective cohort study included adult patients who underwent EVAR in the University Medical Centre Utrecht between January 2010 and July 2015 and who had a total aortic, thoracic aortic, or pulmonary CTA within one month post-operatively. Baseline and mortality data were obtained by reviewing hospital and general practitioner records. The primary outcome was pulmonary embolism within one month after surgery. Secondary outcomes were 30 day and six month mortality.
During the study period, 526 EVARs were performed. Seventy-four of these procedures were included in the analysis of which there were 40 thoracic and 34 abdominal EVARs. In nine patients (12%, 95% CI 7–22) pulmonary embolism was observed of which one was central, two were segmental, and six were subsegmental. Seven were clinically silent and two were present on the pre-operative CTA. Thirty day mortality was significantly higher in patients with pulmonary embolism (relative risk 14.4, 95% CI 1.4–143, p = .037) though none of the deaths seemed directly attributable to it.
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The present study sought to estimate the frequency of overseen and unreported (i.e., false negative) pulmonary embolism (PE) events in oncologic patients. In a retrospective analysis, 3270 patients (6780 computed tomography examinations) were reviewed. Unreported PE was found in 74 patients (2.3%). It was particularly frequent in follow-up staging examinations in patients with metastasized malignancies of the lung and kidney. The present data support the thesis that the search error (thrombus was never fixed by the eyes of the reviewer) was the most common reason why PE was overseen.
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ReviewClinical Recognition of Pulmonary Embolism: Problem of Unrecognized and Asymptomatic Cases

Section snippets

PROSPECTIVE DIAGNOSTIC AND TREATMENT STUDIES OF PE

AUTOPSY STUDIES OF PE

CHRONIC THROMBOEMBOLIC PULMONARY HYPERTENSION

SCREENING FOR PE IN PATIENTS WITH DVT

SCREENING FOR PE IN POSTOPERATIVE PATIENTS

CONCLUSION

Prog Cardiovasc Dis

Blood

Mayo Clin Proc

Am J Cardiol

Chest

Am J Med

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Am J Med

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Prog Cardiovasc Dis

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Pathol Res Pract

Mayo Clin Proc

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Clin Chest Med

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Chest

Am J Surg

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Venous thromboembolism

Am Rev Respir Dis

Venous thromboembolism

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Review
Clinical Recognition of Pulmonary Embolism: Problem of Unrecognized and Asymptomatic Cases