Preexisting Chronic Thromboembolic Pulmonary Hypertension in Acute Pulmonary Embolism

BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) is considered a complication of pulmonary embolism (PE). However, signs of CTEPH may exist in patients with a first symptomatic PE.RESEARCH QUESTION: Which radiologic findings on CT pulmonary angiography (CTPA) at the time of acute PE could indicate the presence of preexisting CTEPH?STUDY DESIGN AND METHODS: This study included unselected patients with acute PE who were prospectively followed up for 2 years with a structured visit schedule. Two expert radiologists independently assessed patients' baseline CTPAs for preexisting CTEPH; in case of disagreement, a decision was reached by a 2:1 majority with a third expert radiologist. In addition, the radiologists checked for predefined individual parameters suggesting chronic PE and pulmonary hypertension.RESULTS: Signs of chronic PE or CTEPH at baseline were identified in 46 of 303 included patients (15%). Intravascular webs, arterial narrowing or retraction, dilated bronchial arteries, and right ventricular hypertrophy were the main drivers of the assessment. Five (1.7%) patients were diagnosed with CTEPH during follow-up. All four patients diagnosed with CTEPH early (83-108 days following acute PE) were found in enriched subgroups based on the experts' overall assessment or fulfilling a minimum number of the predefined radiologic criteria at baseline. The specificity of preexisting CTEPH diagnosis and the level of radiologists' agreement improved as the number of required criteria increased. INTERPRETATION: Searching for predefined radiologic parameters suggesting preexisting CTEPH at the time of acute PE diagnosis may allow for targeted follow-up strategies and risk-adapted CTEPH screening, thus facilitating earlier CTEPH diagnosis.

Automated summary

This study found that 15% of patients with acute pulmonary embolism (PE) showed signs of chronic PE or chronic thromboembolic pulmonary hypertension (CTEPH) on CT pulmonary angiography (CTPA). Specific radiologic parameters, such as intravascular webs, arterial narrowing or retraction, dilated bronchial arteries, and right ventricular hypertrophy, could help identify preexisting CTEPH. Early diagnosis of CTEPH can be facilitated by targeted follow-up strategies and risk-adapted CTEPH screening based on these parameters.