Diagnostic strategies in the preintervention and postintervention periods
| Strategy | Preintervention period N=652 | Postintervention period N=711 | p Value |
|---|---|---|---|
| Initial pretest probability assessed | |||
| Yes | 183 (28%) | 661 (93%) | <0.001 |
| Test combination performed | |||
| D-dimer alone | 229 (35%) | 304 (43%) | 0.004 |
| D-dimer, CTPA | 36 (5.5%) | 119 (17%) | <0.001 |
| D-dimer, VQ scan | 24 (3.7%) | 25 (3.5%) | 0.88 |
| D-dimer, CTPA, VQ scan | 21 (3.2%) | 0 (0.0%) | <0.001 |
| CTPA alone | 279 (43%) | 216 (30%) | <0.001 |
| CTPA, VQ scan | 26 (4.0%) | 15 (2.1%) | 0.06 |
| VQ scan alone | 37 (5.7%) | 32 (4.5%) | 0.32 |
CTPA, CT pulmonary angiography; VQ scan, ventilation-perfusion scan.