Lisette van Dam

Chapter 11 174 independent predictors of residual PVO assessed by V/Q scan. 3,4 These persistent pulmonary perfusion defects have been associated with functional limitations during long-term follow-up and CTEPH. 3,6 In a study of 647 PE patients, 3.4% of patients with residual PVO after 6 months of the initial PE diagnosis were diagnosed with CTEPH versus none of the patients without residual PVO. 6 We therefore hypothesized that the extend of perfusion defects at initial PE diagnosis could be of value for predicting persistent symptoms and adverse events at 3-month follow-up. However, we had to reject our hypothesis: the extent of perfusion defects on CTPP did not show a trend towards an association with persistent dyspnea or pain. Of note, discrepancy between the extent of perfusion defects and symptoms including dyspnea and pain may exist as the generation of dyspnea and pain involve multiple underlying complex (and not fully understood) mechanisms. 11 Moreover, as the study represents a case mix of patients from the LUMC including patients with a history of VTE and active malignancy, it cannot be ruled out that the predictive value of PDS for persistent symptoms and adverse outcomes is different in other settings or hospitals. We also assessed whether PDS on CTPP at PE diagnosis could predict recurrent VTE, PE-related readmission and all-cause mortality. In the current literature, there is evidence that the extend of baseline perfusion defects is associated with persistent perfusion defects on V/Q scans, the latter predicting recurrent VTE. 6,12 In the recent PADIS-PE trial, including 371 patients with first unprovoked PE treated with anticoagulants for 6 months, persistent perfusion defects of more than 5% determined by V/Q scan was associated with increased risk for recurrent VTE (hazard ratio of 2.06, 95%CI 1.14-3.72). 12 Since only one recurrent VTE event occurred during 3-month follow-up in our study cohort, we were not able to assess whether the extent of perfusion defects at initial PE diagnosis could predict recurrent VTE. Our study has limitations. First, the presence of dyspnea and functional limitations was self-reported, which may have introduced bias 8 , rather than assessed with a validated instrument such as the Post-VTE Functional Status (PVFS) scale. Further, this was an exploratory study in which we focused on a convenience cohort of 100 patients without a specific sample size calculation and followed patients for 3 months without taking longer follow-up into account. However, since our data did not even show a trend towards an association between perfusion defects and persistent symptoms or adverse outcomes, we expect that a larger sample size would not make a difference and show the same results. Furthermore,