The challenge of diagnosing pulmonary embolism in elderly patients: influence of age on commonly used diagnostic tests and strategies.

Pulmonary embolism (PE) is a potentially fatal disease if left untreated. The prevalence of PE increases markedly with age, and its diagnosis in elderly people is difficult because many cardiopulmonary conditions may mimic clinical presentation of PE, and age may unfavorably influence the characteristics of diagnostic tests for PE. The modern approach to PE is based on sequential diagnostic strategies based on clinical probability, D-dimer measurement, lower limb compression ultrasonography, ventilation-perfusion lung scan, and helical computed tomography (hCT). Pulmonary angiogram is rarely necessary because the noninvasive diagnostic evaluation is usually conclusive. Age reduces the clinical usefulness of D-dimer and ventilation-perfusion lung scan. D-dimer allows excluding PE in only 5% of patients aged 80 and older, compared with 60% younger than 40. Similarly, the rate of inconclusive ventilation-perfusion lung scans is almost twice as high (58%) in patients older than 70 and in patients younger than 40 (32%). In contrast, aging does not change the diagnostic accuracy of clinical probability assessment, whether empirical or as determined by prediction rules, nor appear to influence the diagnostic characteristics of lower limb compression ultrasonography and hCT. Therefore, a rational diagnostic approach to PE in older people should rest mainly on the sequential use of those tests that have demonstrated strong diagnostic yield, accuracy, and safety in this population.