Computed tomography pulmonary embolism residua index (CTPER-index): a simple tool for pulmonary embolism residua description

OBJECTIVE Chronic thromboembolic pulmonary hypertension (CTEPH) is a relatively common long-term complication of acute pulmonary embolism (PE) with severely negative impact on the patient's quality of life and prognosis. The aim of our study was to assess morphological changes, with respect to CTEPH development, in the pulmonary artery vascular bed 6 months after diagnosis of acute PE as the first thromboembolic event in the patient`s history. METHODS Our prospective study included a population of 87 consecutive patients with proven PE. Multidetector computer tomography pulmonary arteriography (CTA) was performed 6 months after acute PE to assess residua of thrombi and abnormalities supporting the presence of pulmonary hypertension. To quantify the individual totality of morphological abnormalities, a computer tomography pulmonary embolism residua index (CTPER-index) was constructed and groups of patients with and without CTEPH were compared. The study follow-up was 24 months, with echocardiography performed 6, 12, and 24 months after PE. RESULTS Morphological abnormalities corresponding to thrombi residua or pulmonary hypertension on CTA were found in 68% of patients. The CTPER-index reached significantly higher values in patients with CTEPH during a 2-year follow-up. A CTPER-index value ≥4 equates to a 12-fold higher risk of CTEPH development (p=0.013) with sensitivity 0.80 (95% CI 0.31; 0.989) and specificity 0.79 (95% CI 0.754; 0.799). CONCLUSION Our CTPER-index may provide useful information for a clinician performing CTA for differential diagnosis of dyspnea in a patient with a history of PE.