Validation of SEARCH, a Novel Hierarchical Algorithm to Define Long-term Outcomes After Pulmonary Embolism

Study Summary

Potential outcomes after PE occur on a spectrum: complete recovery, exercise intolerance from deconditioning/anxiety, dyspnea from concomitant cardiopulmonary conditions, dyspnea from residual pulmonary vascular occlusion, chronic thromboembolic disease and chronic thromboembolic pulmonary hypertension. Although a battery of advanced diagnostic tests could distinguish each of those conditions, the yield of individual tests among all post- PE patients is low enough that routine testing of all PE patients is not typically performed. Although the various possible post-PE outcomes have enormous implications for patient care, they are rarely distinguished clinically. Perhaps for this reason, chronic conditions after PE are rarely (if ever) used as endpoints in randomized clinical trials of acute PE treatment. The proposed project will validate a clinical decision tree to distinguish among the various discrete outcomes cost-effectively through a hierarchical series of tests with the acronym SEARCH (for symptom screen, exercise function, arterial perfusion, resting heart function, confirmatory imaging and hemodynamics). Each step of the algorithm sorts a subset of patients into a diagnostic category unequivocally in a cost-effective manner. The categories are mutually exclusive and collectively exhaustive, so that each case falls into one, and only one, category. Each individual test used in the algorithm has been clinically validated in pulmonary embolism patients, including the cardiopulmonary exercise test (CPET) technique that the investigators developed and validated. However, the decision tree approach to deploying the tests has not yet been validated. Aim 1 will determine whether the SEARCH algorithm will yield concordant post-PE diagnoses when multiple reviewers independently evaluate multiple cases (reliability). Aim 2 will determine whether the post-PE diagnoses are stable, according to the SEARCH algorithm, between the first evaluation and the subsequent one

Primary Outcome

Based on a structured evaluation of clinical data generated during long term follow-up after PE and presented in a de-identified manner, six observers will independently categorize each patient as one of the following: 1. complete recovery from dyspnea and exercise intolerance to the state that pre-existed PE or dyspnea after PE but cardiopulmonary exercise test showing normal ventilatory dead space proportions (VD/VT) and normal estimated stroke volume augmentation (SVA) during exercise; 2. dy

Interventions

• OTHER SEARCH algorithm