Assessing the role of Computed Tomography Pulmonary Angiogram in diagnosing right heart strain related to acute pulmonary embolism

Introduction/Objective Right heart strain (RHS) is a commonly occurring and significant complication of acute pulmonary embolism (PE). CTPA images often suggest pulmonary hypertension; however, diagnostic echocardiography is not always immediately available to confirm this. In this study, we assessed how accurately Computed Tomography Pulmonary Angiography (CTPA), troponin, and NT-proBNP predict evidence of RHS in patients with acute PE, compared with transthoracic echocardiography (TTE). Methods A total of 656 patients had CTPAs performed over 6 months at a tertiary university hospital. Studies positive for PE were then separated into those with and without reported CTPA evidence of RHS. Patients’ TTE, troponin-T, NT-proBNP, and D-dimer results were assessed, and potential relationships were explored. Results About 128 (19.5%) studies were positive for acute PE, and 25 patients with RHS on CTPA had TTEs, with 16 showing evidence of RHS. A total of 39 patients with PEs and no CTPA-reported RHS had TTEs, with 7 suggesting RHS. CTPAs showed a 69.6% sensitivity and 78.0% specificity in predicting RHS. NT-pro-BNP (cut-off 300pg/ml) and troponin-T (cut-off 34ng/L) showed higher sensitivity, 92.9% and 75%, respectively, and lower specificity, 33.3% and 58%, respectively, than CTPA. 329/656 (50%) had an alternative explanation for symptoms on CTPA, meaning only 30.5% of patients had no explanation for symptoms. Discussion While an accessible and useful test, CTPA is not as reliable in predicting RHS in patients with acute PE as TTE. Conclusion Patients diagnosed with a clinically significant PE should be considered for TTE regardless of whether or not RHS is evident on CTPA.