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Clinicians should stratify patients with suspected acute pulmonary embolism (PE) to ensure use of the appropriate diagnostic strategy, according to guidelines from the American College of Physicians (ACP).
The ACP’s guidelines, published in Annals of Internal Medicine, are designed to help clinicians identify patients who should undergo diagnostic testing for PE—D-dimer and imaging—and those who should not.
“The use of computed tomography (CT) for the evaluation of patients with suspected pulmonary embolism is increasing, despite no evidence that this increased use has led to improved patient outcomes, while exposing patients to unnecessary risks and expense,” said ACP President Wayne J. Riley, MD.
“ACP’s advice is designed to help physicians identify patients for whom a PE is so unlikely that they need no further testing, for whom plasma D-dimer testing can provide additional risk stratification, and for whom imaging is indicated because of their high risk and clinical presentation.”
The guidelines say the first step for clinicians evaluating patients with suspected acute PE is to use a validated clinical prediction rule to estimate the patients’ pre-test probability of PE. The Wells and Geneva rules have been validated and are considered equally accurate in predicting the probability of PE.
In patients who have a low pre-test probability of PE, clinicians should apply the Pulmonary Embolism Rule-Out Criteria (PERC) rule. Clinicians should not obtain D-dimer tests or imaging studies in patients with a low pre-test probability of PE and who meet all 8 PERC.
Patients who have an intermediate pre-test probability of PE or patients with low pre-test probability of PE who do not meet all PERC should have a high sensitivity D-dimer test as the initial step in diagnosis.
Clinicians should not use imaging as the initial test in patients who have a low or intermediate pre-test probability of PE.
Since normal D-dimer levels increase with age, clinicians should use age-adjusted D-dimer thresholds (age times 10 ng/mL rather than a generic 500 ng/mL) in patients older than 50 years to determine whether imaging is warranted.
Clinicians should not use imaging in low- or intermediate-risk patients with a D-dimer below the age-adjusted cutoff.
“While highly sensitive, plasma D-dimer testing is nonspecific, and false-positives can lead to unnecessary imaging,” said guideline author Ali S. Raja, MD, of Massachusetts General Hospital in Boston.
“The use of an age-adjusted threshold resulted in maintenance of sensitivities with improved specificities in all age groups.”
Patients with high pre-test probability of PE should undergo imaging with CT pulmonary angiography. Clinicians should reserve V/Q scans for patients who have a contraindication for CT pulmonary angiography or if CT pulmonary angiography is not available.
Clinicians should avoid obtaining a D-dimer measurement in patients with a high pre-test probability of PE.
