Acute pulmonary embolism pretest probability estimation by d-dimer test, our modified, new ECG score and clinical prediction rules.

Objectives: We investigated whether a sufficiently sensitive D-dimer test could exclude acute pulmonary embolism (acPE) as a stand-alone diagnostic test and compared our previously published, modified ECG score with the Wells and Geneva scores in the estimation of acPE pretest probability.

Methods: We retrospectively evaluated 345 patients who underwent chest CT angiography (CTA) for the suspicion of acPE. The pretest probability of acPE was assessed in 120 D-dimer negative [DD (-)] and 225 D-dimer positive [DD (+)] patients.

Results: Chest CTA verified acPE in 57/345 (16.5 %) patients and in 1/120 (0.8 %) DD (-) patient. In DD (-) patients the test accuracy (TA) and specificity (SP) of the ECG score (98 %, 99 %) were better than those of the Wells score (92.5 %, 92.4 %) (p = 0.063 and p < 0.05 respectively) and the Geneva score (76.7 %, 76.5 %) (p < 0.001 for both), the Wells score TA and SP were greater than those of the Geneva score (p < 0.001 for both). In DD (+) patients the SPs, TAs and positive predictive values (PPV) of the ECG score (94 %, 78.6 %, 69 %) and the Wells score (91.8 %, 75.1 %, 48 %) were greater than those of the Geneva score (71.3 %, 64.9 %, 38.2 %) (p < 0.001 for both SP and TA respectively, and p < 0.001 for PPV of the ECG score vs. the Geneva score and p < 0.05 for PPV of the Wells score vs. Geneva score), their sensitivities (SE) (36.4 %, 23.6 %) were less than that of the Geneva score (47.5 %) (p < 0.05 and p < 0.001 respectively). The ECG score's TA in a trend, its SE and PPV were significantly (p < 0.01 and p < 0.001) better than those of the Wells score.

Conclusion: In contrast to the current guidelines, a stand-alone high sensitivity DD (-) test, without prediction rules, could reliably exclude acPE. Our ECG score slightly outperformed the Wells score, the ECG score and Wells score far outperformed the Geneva score in the estimation of acPE pretest probability. An acPE diagnosis with the ECG score, in addition to the supportive diagnosis with the clinical prediction rules, may further increase the chance of true DD positivity.