On diagnostic procedures in pulmonary embolism

Pulmonary embolism (PE) and deep venous thrombosis (DVT) are two entities of venous thromboembolism (VTE). PE is a common cause of mortality and morbidity. The symptoms and signs of PE are difficult to interpret, and the diagnosis is difficult to establish. Other diseases can have a similar clinical presentation as PE, increasing the risk for misdiagnosis and inappropriate treatment. A rapid and prompt diagnosis of PE is crucial and has an impact on the mortality rate. In Paper I, we studied 90 hemodynamically stable patients with suspected PE. Computed tomography of the pulmonary arteries (CTPA), and pulmonary arteriography (PA) were performed, the D-dimer was measured, and the diagnostic accuracy of these tests was compared. The prevalence of PE was 37%. CTPA had a positive predictive value (PPV) of 94% and a negative predictive value (NPV) of 95%. With a cut-off of D-dimer of 0.25 mg/L, the PPV was 63% and the NPV was 92%. We concluded that CTPA has a higher sensitivity than D-dimer for diagnosing PE, and that a cut-off value of 0.25 mg/L is sufficient as a screening method, although CTPA is recommended to exclude false positive cases. In Paper II, we retrospectively examined the symptoms and signs in a group of patients with PE (PE/infection, n=25), who were misdiagnosed initially with pneumonia and compared these with the symptoms and signs of patients with correct diagnoses of PE, (PE/medicine, n=64) and community-acquired pneumonia, (CAP, n=54). Dyspnoea and pleuritic chest pain as initial symptoms contributed to 76% (PE/infection), 81% (PE/medicine) and 9% (CAP). Fever, chills, or cough contributed to 8%, 16%, and 80%, respectively. Body temperature, Creactive protein (CRP), and the presence of pulmonary infiltrates on chest X-rays were higher in PE/infection and CAP than in PE/medicine. The symptoms did not differ significantly between the two PE groups. Dyspnoea and pleuritic chest pain were the predominant initial symptoms in patients with PE whereas fever and cough were the predominant symptoms in patients with CAP. High levels of CRP and the presence of pulmonary infiltrates did not exclude PE. In Paper III, we studied 151 patients with suspected DVT and PE with a Wells pretest probability score ≤1.5 points and a D-dimer