Prognostic Factors for Pulmonary Embolism

Ambulatory management of pulmonary embolism: a pragmatic evaluation

BACKGROUND

Patients diagnosed with pulmonary embolism should be considered for treatment on an outpatient basis; however, this practise is not accepted in many centers.

OBJECTIVES

Review the safety and efficacy of ambulatory management of patients with pulmonary embolism at our institution.

PATIENTS/METHODS

This was a retrospective single center cohort study of consecutive patients diagnosed with idiopathic or secondary pulmonary embolism between January 2003 and January 2008 at the London Health Sciences Centre in London, Ontario, Canada. Patients were eligible for outpatient management of pulmonary embolism if they were hemodynamically stable, did not require oxygen therapy, did not require parenteral narcotics for pain management, and were not felt to be high risk for a major hemorrhage. Patients were assessed at 3 months for thrombosis recurrence and major bleeding episodes.

RESULTS

Six hundred and thirty-nine patients were included in the study, of which 314 (49.1%; 95% CI 45.2, 53.1) were managed as outpatients; among these there were three (0.95%; 95% CI, 0.25, 3) thrombotic recurrences and three hemorrhagic events. There were nine deaths (2.9%; 95% CI, 1.4, 5.6), all due to underlying cancer and all occurring after the first 7 days of treatment.

CONCLUSIONS

Outpatient management of uncomplicated pulmonary embolism seems safe and effective in the absence of other indications for hospital admission.

Pulmonary thromboembolic disease. Clinical management of acute and chronic disease

Pulmonary thromboembolism falls between the areas of pulmonology and cardiology, internal medicine and intensive care, radiology and nuclear medicine, and hematology and cardiothoracic surgery. Depending on their clinical background, physicians faced with a patient with a pulmonary thromboembolism may speak different languages and adopt different treatment approaches. Now, however, there is an opportunity to end the Tower of Babel surrounding pulmonary thromboembolism. There is a growing acknowledgement that the key clinical problems in both acute pulmonary embolism and chronic thromboembolic pulmonary hypertension are linked to right ventricular pressure overload and right ventricular failure. As a result, cardiologists and cardiac intensive care specialists are taking an increasing interest in understanding and combating these conditions. The European Society of Cardiology was the first to elaborate comprehensive clinical practice guidelines for pulmonary thromboembolism and chronic thromboembolic pulmonary hypertension. The task forces involved in producing these guidelines included radiologists, pulmonologists, hematologists, intensive care physicians and surgeons, which ensured that the final document was universally acceptable. The aim of this article was to provide an overview of the epidemiology, risk factors, diagnosis, treatment, prognosis and prevention of acute pulmonary thromboembolism and chronic thromboembolic pulmonary hypertension, while taking into account European Society of Cardiology guidelines and incorporating new evidence where necessary.

Risk stratification of normotensive patients with acute symptomatic pulmonary embolism

Treatment guidelines recommend strong consideration of thrombolysis in patients with acute symptomatic pulmonary embolism (PE) that present with arterial hypotension or shock because of the high risk of death in this setting. For haemodynamically stable patients with PE, the categorization of risk for subgroups may assist with decision-making regarding PE therapy. Clinical models [e.g. Pulmonary Embolism Severity Index (PESI)] may accurately identify those at low risk of overall death in the first 3 months after the diagnosis of PE, and such patients might benefit from an abbreviated hospital stay or outpatient therapy. Though some evidence suggests that a subset of high-risk normotensive patients with PE may have a reasonable risk to benefit ratio for thrombolytic therapy, single markers of right ventricular dysfunction (e.g. echocardiography, spiral computed tomography, or brain natriuretic peptide testing) and myocardial injury (e.g. cardiac troponin T or I testing) have an insufficient positive predictive value for PE-specific mortality to drive decision-making toward such therapy. Recommendations for outpatient treatment or thrombolytic therapy for patients with PE necessitate further development of prognostic models and conduct of clinical trials that assess various treatment strategies.

Mortality risk assessment and the role of thrombolysis in pulmonary embolism

Acute venous thromboembolism remains a frequent disease, with an incidence ranging between 23 and 69 cases per 100,000 population per year. Of these patients, approximately one-third present with clinical symptoms of acute pulmonary embolism (PE) and two-thirds with deep venous thrombosis (DVT). Recent registries and cohort studies suggest that approximately 10% of all patients with acute PE die during the first 1 to 3 months after diagnosis. Overall, 1% of all patients admitted to hospitals die of acute PE, and 10% of all hospital deaths are PE-related. These facts emphasize the need to better implement our knowledge on the pathophysiology of the disease, recognize the determinants of death or major adverse events in the early phase of acute PE, and most importantly, identify those patients who necessitate prompt medical, surgical, or interventional treatment to restore the patency of the pulmonary vasculature.

Acute pulmonary embolism. Part 1: epidemiology and diagnosis

Pulmonary embolism (PE) is a frequently occurring, acute, and potentially fatal condition. Numerous risk factors for PE, both inherited and acquired, have been identified. Adequate diagnosis is mandatory to prevent PE-related morbidity and mortality on the one hand, and unnecessary treatment on the other. Only around 1 in 5 individuals with suspected PE will have the diagnosis confirmed, therefore, the diagnostic work-up for PE should comprise safe, efficient, and noninvasive methods. The first step in the approach to diagnosis of patients with suspected PE is to determine the clinical probability and to perform a D-dimer test. PE can be excluded in patients with a 'low', 'intermediate' or 'unlikely' clinical probability and a normal D-dimer test. Additional imaging is required for those with a 'high' or 'likely' clinical probability or a positive D-dimer test. CT pulmonary angiography or ventilation-perfusion scintigraphy, followed by additional testing is the next step when test results are nondiagnostic. Although various diagnostic strategies have been introduced and validated, selected patients may require a tailored approach.

Validation of a clinical algorithm to identify low-risk patients with pulmonary embolism

BACKGROUND

We previously derived a clinical prognostic algorithm to identify patients with pulmonary embolism (PE) who are at low risk of short-term mortality and who could be safely discharged early or treated entirely in an outpatient setting.

OBJECTIVES

To externally validate the clinical prognostic algorithm in an independent patient sample.

METHODS

We validated the algorithm in 983 consecutive patients prospectively diagnosed with PE at an emergency department of a university hospital. Patients with none of the algorithm's 10 prognostic variables (age > or = 70 years, cancer, heart failure, chronic lung disease, chronic renal disease, cerebrovascular disease, pulse > or = 110 min(-1), systolic blood pressure < 100 mmHg, oxygen saturation < 90%, and altered mental status) at baseline were defined as being at low risk. We compared 30-day overall mortality among low-risk patients, on the basis of the algorithm, between the validation sample and the original derivation sample. We also assessed the rate of PE-related and bleeding-related mortality among low-risk patients.

RESULTS

Overall, the algorithm classified 16.3% of patients with PE as being at low risk. Mortality at 30 days was 1.9% among low-risk patients, and did not differ between the validation sample and the original derivation sample. Among low-risk patients, only 0.6% died from definite or possible PE, and 0% died from bleeding.

CONCLUSIONS

This study validates an easy-to-use, clinical prognostic algorithm for PE that accurately identifies patients with PE who are at low risk of short-term mortality. Patients who are at low risk according to our algorithm are potential candidates for less costly outpatient treatment.