Diagnostic and prognostic value of a diagnostic CT regression model in suspected pulmonary hypertension

Background: Computed tomography (CT) pulmonary angiography is widely used in patients with suspected pulmonary hypertension (PH). However, the diagnostic and prognostic significance remains unclear. The aim of this study was to (a) build a diagnostic CT model and (b) test its prognostic significance. Methods: Consecutive patients with suspected PH undergoing routine CT pulmonary angiography and right heart catheterization (RHC) were identified. Reconstructed images were used to derive CT metrics. Multivariate regression analysis was performed in the derivation cohort to identify a diagnostic CT model to predict mPAP ≥25mmHg and >20mmHg. In the validation cohort, sensitivity, specificity and compromise CT thresholds were identified with receiver operating characteristics (ROC) Results: Between 2012 and 2016, 491 patients were identified. In the derivation cohort, n=247, a CT model was identified including pulmonary artery diameter, right ventricular outflow tract thickness, septal angle and left ventricular area. In the validation cohort, n=244, the model was diagnostic, area under the ROC curve 0.94/0.91 for mPAP≥25/>20mmHg. In the validation cohort 93 patients died, mean follow-up of 42 months. The sensitive/specific/compromise thresholds for the CT model were prognostic, log rank 11.1/10.6/6.25 respectively, all p 20mmHg were not prognostic, p=0.09 and p=0.12, respectively. Conclusion: In suspected PH, a diagnostic CT model had diagnostic and prognostic utility. Conversely, the presence or absence of PH at RHC did not predict survival.