There were 1,566 patients included in this study; 265 had positive (17%), and 1,301 (83%) had negative CTPAs. The cohort included 840 female and 726 male patients, aged between 18 and 103 years old, with a median age of 64. The main reason for a patient visiting the ED was dyspnea (n = 950), chest pain (n = 317), syncope (n = 44), abdominal pain (n = 28), cough (n = 23), cardiac arrest (n = 16), hemoptysis (n = 14), back pain (n = 11), tachycardia (n = 8) and other (n = 143) as shown in Fig. 1.
The distribution levels of the emboli were as followed: central/lobar (n = 137), segmental (n = 73) and subsegmental (n = 55). In 257 cases, an alternative diagnosis could entirely or partially explain the patient’s symptoms, such as pleural or pericardial effusion, pneumonia, chronic obstructive pulmonary disease exacerbation, suspected metastasis, primary malignancy, or bronchiolitis. D-dimer was tested for in 751 patients (48%). There was mention of CDSS in the EMR only in 74 (5%) out of the 1,566 patients.
The clinical hunch group contained 786 patients who fulfilled the inclusion criteria, with 118 positive (15%) and 668 negative (85%) cases, resulting in a yield of 15%.
The PERC rule resulted in 1421 patients in the not-excluded group, of whom 256 had a positive and 1165 a negative CTPA, resulting in a yield of 18%. Out of the 145 patients excluded, 9 had a positive and 136 a negative CTPA, resulting in a yield of 7%. When overriding the PERC rule, the yield was lowered from 18 to 6%.
The wells score version A resulted in 844 patients in the high-risk group, of whom 177 had a positive, and 667 a negative CTPA. Of the 722 patients in the low-risk group, 318 had a positive D-dimer, of whom 45 had a positive and 273 a negative CTPA resulting in a yield of 19%. Of the remaining 404 patients who had a negative or no D-dimer, 43 had a positive and 361 a negative CTPA, resulting in a yield of 11%. When overriding the Wells score, the yield was lowered from 19 to 11%.
The Wells score version B resulted in 147 patients in the high-risk group, of whom 42 had a positive, and 105 a negative CTPA. Out of the 1419 patients in the low-risk group, 593 had a positive D-dimer, of whom 112 had a positive, and 481 a negative CTPA resulting in a yield of 21%. Of the remaining 826 patients who had a negative or no D-dimer, 111 had a positive and 715 a negative CTPA, resulting in a yield of 13%. When overriding the Wells score, the yield was lowered from 21% to 13.
The Revised Geneva score resulted in 113 patients in the high-risk group, of whom 39 had a positive, and 74 a negative CTPA. Of the 970 patients in the intermediate-risk group, 378 had a positive D-dimer, of whom 88 had a positive, and 290 a negative CTPA, resulting in a yield of 26%. Of the remaining 1075 patients who had a negative, or no D-dimer, or were in the low-risk group, 93 had a positive, and 982 a negative CTPA, resulting in a yield of 13%. When overriding the revised Geneva score, the yield was lowered from 26 to 13%.
The Years criteria Version A group contained 751 patients who fulfilled the inclusion criteria by having the D-dimer tested. This resulted in 657 patients in the not-excluded group, of whom 121 had a positive, and 519 a negative CTPA. Of 94 patients in the excluded group, 6 had a positive and 88 a negative CTPA resulting in a yield of 18%. When overriding the YEARS criteria version A, the yield was lowered from 18 to 6%.
The Years criteria Version B resulted in 465 patients in the not-excluded group, of whom 126 had a positive, and 339 a negative CTPA. Of the 286 patients in the excluded group, 18 had a positive and 268 a negative CTPA resulting in a yield of 27%. The remaining 904 patients had no D-dimer and therefore could not be included. When overriding the YEARS criteria version B, the yield was lowered from 27 to 6%. Figures 2 and 3 visualize the results and the yield when bypassed.
A total of 94 patients had a negative d-dimer. Three had PE at the subsegmental level. The main complaint was dyspnoea (n = 2), haemoptysis (n = 1).
In 55 cases, the CTPA was ordered after the results of the d-dimer were available. The average time between the d-dimer result and the CTPA order was 3 h: 30 min (minimum 4 min and maximum 23 h: 42 min).
In 17 cases, the CTPA was ordered before the d-dimer with an average time difference of 42 min. (minimum 1 min and maximum 3 h: 54 min).
In 22 cases, the CTPA was ordered after the d-dimer with an average time between the orders of 24 min. (minimum 1 min, maximum 57 min).