Lisette van Dam

CTPP for short-term clinical outcome prediction in acute PE 10 163 DISCUSSION We showed that perfusion defects on CTPP are correlated to reperfusion therapy and PE-related mortality and that the addition of PDS assessment to CTPA assessment of RV/LV ratio, pulmonary artery trunk diameter and total thrombus load improved the predictive value of the model to predict PE-related mortality, but not ICU admission nor reperfusion therapy. Moreover, perfusion defects on CTPP did not correlate to clinical symptoms at presentation. Risk stratification of patients with acute PE is crucial for deciding on the optimal treatment, including hospitalization, close hemodynamic monitoring and reperfusion therapy. 1,22,23 Previous studies found that right ventricle enlargement (RV/LV ratio > 1.0) is associated with an increased risk for PE-related mortality. 24-26 Current European guidelines therefore recommend assessment of right ventricular dimensions or function as part of initial risk stratification. 22 As previous publications have shown that CTPP-assessed PDS is correlated to RV/LV ratio and total thrombus load 6-10 , perfusion imaging may play a role in this risk stratification. Although our results showed an improvement in the predictive capacity for PE- related mortality when PDS was added to CTPA-reading, the improvement in AUC was only marginally. Furthermore, we could not confirm an added value of PDS over CTPA assessment to predict ICU admission nor reperfusion therapy. A possible explanation may be the low incidence of these adverse outcomes (range between 2 to 7 patients). We also evaluated whether perfusion defects on CTPP were correlated to clinical symptomsat presentation. This is relevant, aspainanddyspnea forwhich treatment with intravenous pain medication and oxygen therapy may be needed are also relevant for the decision for hospitalization or home-treatment. 27,28 However, an association between PDS and presenting symptoms could not be established. Of note, as the generation of dyspnea and chest pain involve multiple underlying (complex and not fully understood) mechanisms, a discrepancy between chest pain and dyspnea and extent of perfusion defects in acute PE is possible. 29 PDS was also not correlated to hospital admission. However, the decision to admit a patient to the hospital is often based on multiple variables, some not included in this analysis, including pregnancy, active bleeding and the presence of a social reason for treatment in hospital. In current literature, the addition of CTPP to CTPA was found to improve the specificity in the PE detection from 94% (95%CI 89-97%) to 100% (95%CI 100-100%)