Frequency and predictors for chronic thromboembolic pulmonary hypertension after a first unprovoked pulmonary embolism: Results from PADIS studies

Background Chronic thromboembolic pulmonary hypertension (CTEPH) is a life‐threatening complication of a pulmonary embolism (PE) whose incidence and predictors are not precisely determined. Objective To determine the frequency and predictors for CTEPH after a first unprovoked PE. Patients/Methods In a randomized trial comparing an additional 18‐month warfarin versus placebo in patients after a first unprovoked PE initially treated with vitamin K antagonist for 6 months, we applied recommended CTEPH screening strategies through an 8‐year follow‐up to determine cumulative incidence of CTEPH. CTEPH predictors were estimated using Cox models. Pulmonary vascular obstruction (PVO) and systolic pulmonary arterial pressure (sPAP) at PE diagnosis and 6 months were studied by receiver operating curves analysis. All CTEPH cases and whether they were incident or prevalent were adjudicated. Results During a median follow‐up of 8.7 years, nine CTEPH cases were diagnosed among 371 patients, with a cumulative incidence of 2.8% (95% confidence interval [CI] 0.95–4.64), and of 1.31% (95% CI 0.01–2.60) after exclusion of five cases adjudicated as prevalent. At PE diagnosis, PVO > 45% and sPAP > 56 mmHg were associated with CTEPH with a hazard ratio (HR) of 33.00 (95% CI 1.64–667.00, p = .02) and 12.50 (95% CI 2.10–74.80, p 65 years, lupus anticoagulant antibodies and non‐O blood groups were also predictive of CTEPH. PVO > 14% and sPAP > 34 mmHg at 6 months were associated with CTEPH (HR 63.90 [95% CI 3.11–1310.00, p