Using VQ SPECTCT Imaging to Measure Residual Lung Blood Flow Blockage and Predict Recurrence Risk of Blood Clots in Patients Who Had a Pulmonary Embolism

What this Trial Is About

This research investigates patients who have experienced pulmonary embolism PE and focuses on the risk of PE recurrence, which can be fatal in about 10% of cases. Patients with PE are grouped by recurrence risk into very low, high, or intermediate categories, with limited knowledge about those at intermediate risk. The study aims to explore how residual pulmonary vascular obstruction RPVO, measured more accurately by a new 3-dimensional imaging method called VentilationPerfusion Single Photon Emission Computed Tomography VQ SPECTCT, may predict recurrence in these intermediate-risk patients. Participants are patients who had an objectively confirmed PE and were treated with anticoagulant therapy continuously for 3 to 6 months without plans to continue anticoagulation. All participants will undergo a VQ SPECTCT scan at the start of the study to assess RPVO. The study will observe these patients for 24 months to track symptomatic recurrent venous thromboembolism VTE events, including nonfatal PE, deep vein thrombosis, or fatal PE. During the study, researchers will collect data on various predictors of PE recurrence and assess patients quality of life and breathing difficulty using specific questionnaires at the start and after 6 months. They will also monitor mortality, chronic pulmonary hypertension, and other health outcomes over 24 months. This follow-up will help determine if RPVO measured by VQ SPECTCT is a valuable tool to predict recurrence risk in this patient group.

Residual Pulmonary Vascular Obstruction Index Computed With Ventilation/Perfusion SPECT/CT Imaging to Predict the Risk of Venous Thromboembolism Recurrence in Patients With Pulmonary Embolism (PRONOSPECT)