Accurate and efficient non-invasive strategy for early identification of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism (InShape II study)

Abstract

Abstract Background The current diagnostic delay of chronic thromboembolic pulmonary hypertension (CTEPH) after acute pulmonary embolism (PE) is unacceptably long exceeding 1 year, causing loss of quality-adjusted life years and excess mortality. Validated screening strategies to diagnose CTEPH earlier are lacking. Importantly, performing echocardiography in all PE patients for this purpose has a low diagnostic yield, is associated with overdiagnosis and is not cost-effective. Moreover, expertise in performing high-quality PH-dedicated echocardiograms may not be available outside expert centers. Aim To validate a simple screening strategy aimed at identifying CTEPH early in the course after acute PE, avoiding echocardiography if possible (Figure 1). Methods In this prospective, international, multicenter management study, consecutive PE survivors were managed according to the predefined algorithm starting three months after acute PE. All were followed for a total period of two years. The study protocol was approved by all local IRBs and all patients provided informed consent. Results 424 patients were included across three European countries (Table 1). Following the algorithm, CTEPH was considered excluded in 343 (81%) patients based on clinical pre-test probability assessment by the “CTEPH prediction score”, evaluation of symptoms and application of the “CTEPH rule-out criteria” (Figure 1); only 19% was subjected to echocardiography. Only 1 of 343 patients managed without echocardiography was diagnosed with CTEPH, 10 months after initial PE, for a failure rate of 0.29% (95% CI 0–1.6%). Overall, 13 patients were diagnosed with CTEPH (incidence 3.1%), of whom 10 within 4 months after PE diagnosis. Conclusions The algorithm accurately ruled out CTEPH and avoided echocardiography in 81% of patients. The vast majority of CTEPH cases were identified early in the course of acute PE which is a considerable improvement compared to current clinical practice with an economic use of healthcare resources. Figure 1. Study flowchart Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): This study was supported by unrestricted grants from Bayer/Merck Sharp & Dohme (MSD) and Actelion Pharmaceuticals Ltd. F.A. Klok and G.J.A.M. Boon were supported by the Dutch Heart Foundation (2017T064).