A WAY TO SELECT ON CLINICAL GROUNDS PATIENTS WITH HIGH-RISK FOR PULMONARY-EMBOLISM - A RETROSPECTIVE ANALYSIS IN A NESTED CASE-CONTROL STUDY

We studied 196 patients with suspicion of pulmonary embolism (PE), sub sequently confirmed in 98 by positive pulmonary angiography and exclud ed in 98 by normal or near-normal perfusion lung scan. Patients had a clinical questionnaire for history, and, soon after, a radiograph, blo od gas analysis, and an ECG. Clinical and instrumental signs were matc hed in patients with confirmed and unconfirmed PE to find those more f requent in embolic patients and, thus, more characteristic of PE. The following were: previous PE, immobilization and thrombophlebitis (p < 0.05); dyspnea and cough (p < 0.05); enlarged descending pulmonary art ery (DPA), enlarged right heart, pulmonary infarction, Westermark sign (p < 0.001), and elevated diaphragm (p < 0.05); hypoxemia. No ECG sig n was more frequent in PE. Thereafter, all variables were processed se parately with a logistic multiple regression analysis and those signif icantly associated to PE were tested in a final logistic model that wa s able to predict the actual result of angiography or scintigraphy; ac cordingly, previous PE, immobilization, thrombophlebitis, enlarged DPA , pulmonary infarction, Westermark sign, hypoxemia were significantly associated with a high risk of PE (from 2.8 to 15 times greater than i n patients without these signs). Therefore, we may conclude that clini cal assessment and noninvasive tests may help to detect patients at hi gher risk for PE where heparin coverage should be started while waitin g for conclusive diagnostic procedures.