Lisette van Dam

Chapter 10 164 and the detection of occlusive (sub)segmental pulmonary emboli. 30 CTPP was also evaluated for PE prognostication andwas shown to be correlated to adverse clinical outcome including ICU admission, all-cause and PE-related mortality 7,31 , but had no added value to RV/LV ratio to predict mortality. 32,33 Hence, based on our results and available literature, the application of CTPP seems to be mostly relevant for the diagnostic management of acute PE, rather than for prognostication. Limitations of the study are its observational design and the use of a convenience cohort without a specific sample size calculation. This latter may have resulted that the study was underpowered to detect a correlation between PDS and clinical symptoms and some adverse outcomes. On the other hand, the predictive value of perfusion defects for reperfusion therapy and PE-related mortality may be overestimated due to the low incidence of these adverse events and should therefore be interpreted with caution. Furthermore, the presence of clinical symptoms was self-reported and not assessed in a standardized manner, what may have introduced relevant bias. Biasmay also be present in the perfusion defect quantification as perfusion defects may not only be the result of a pulmonary embolism but also of other pathology such as a pneumonia. The strengths of this study are its prospective design and the inclusion of all-comers, which supports the external validity of our findings. Also, CTPA and CTPP assessment was performed by independent readers who were unaware of the clinical presentation and course. In conclusion, PDS was not associated with clinical presentation of acute PE. However, our data showed that CTPP-assessed PDS was correlated to reperfusion therapy and PE-related mortality and improved the predictive value of CTPA- reading for PE-related mortality, but not for ICU admission or reperfusion therapy. Due to the limited number of adverse events and the design or our study, our observations should be considered hypothesis generating. Future larger studies including an upfront determined sample size calculation are needed to determine the clinical relevance of PDS quantification on top of CTPA assessment of right ventricle dysfunction in risk stratification of acute PE.