Optimisation of detecting chronic thromboembolic pulmonary hypertension in acute pulmonary embolism survivors: the InShape IV study.

INTRODUCTION:Chronic thromboembolic pulmonary hypertension (CTEPH) is often diagnosed late in acute pulmonary embolism (PE) survivors: more efficient testing to expedite diagnosis may considerably improve patient outcomes. The InShape II algorithm safely rules out CTEPH (failure rate 0.29%) while requiring echocardiography in only 19% of patients but may be improved by adding detailed reading of the computed tomography pulmonary angiography (CTPA) diagnosing the index PE. METHODS:Twelve new algorithms, incorporating the CTEPH prediction score, ECG reading, NT-proBNP levels and dedicated CTPA reading were evaluated in the international InShape II (n=341) and part of the German FOCUS cohort (n=171). Evaluation criteria included failure rate, defined as the incidence of confirmed CTEPH in PE patients in whom echocardiography was deemed unnecessary by the algorithm, and the overall net reclassification index (NRI) compared to the InShape II algorithm. RESULTS:The algorithm starting with CTPA reading of the index PE for 6 signs of CTEPH, followed by the ECG/NTproBNP assessment and echocardiography resulted in the most beneficial change compared to InShape II with a need for echocardiography in 20% (+5%), a failure rate of 0%, and an NRI of +3.5, reflecting improved performance over the InShape II algorithm. In the FOCUS cohort, this approach lowered echocardiography need to 24% (-6%) and missed no CTEPH cases, with an NRI of +6.0. CONCLUSION:Dedicated CTPA reading of the index PE improved the performance of the InShape II algorithm and may improve the selection of PE survivors who require echocardiography to rule out CTEPH.