Abstract
ObjectivesComputed 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.MethodsConsecutive patients with suspected PH undergoing routine CT pulmonary angiography and right heart catheterisation (RHC) were identified. Axial and 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 ≥ 25 mmHg (the existing ESC guideline definition of PH) and > 20 mmHg (the new threshold proposed at the 6th World Symposium on PH). In the validation cohort, sensitivity, specificity and compromise CT thresholds were identified with receiver operating characteristic (ROC) analysis. The prognostic value of the CT model was assessed using Kaplan-Meier analysis.ResultsBetween 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, with an area under the ROC curve of 0.94/0.91 for mPAP ≥ 25/> 20 mmHg respectively. In the validation cohort, 93 patients died; mean follow-up was 42 months. The diagnostic thresholds for the CT model were prognostic, log rank, all p < 0.01.DiscussionIn suspected PH, a diagnostic CT model had diagnostic and prognostic utility.Key Points• Diagnostic CT models have high diagnostic accuracy in a tertiary referral population of with suspected PH.• Diagnostic CT models stratify patients by mortality in suspected PH.
Highlights
Pulmonary hypertension (PH) has been defined arbitrarily as a mean pulmonary artery pressure of at least 25 mmHg at rest [1]
Consecutive treatment-naïve patients with suspected PH referred to a nationally designated PH centre (Sheffield Pulmonary Vascular Disease Unit) between April 2012 and March 2016 were identified from the ASPIRE Registry MRI database [28]
Inclusion criteria required Computed tomography (CT) pulmonary angiography to be performed within 90 days of right heart catheterisation (RHC)
Summary
Pulmonary hypertension (PH) has been defined arbitrarily as a mean pulmonary artery pressure of at least 25 mmHg at rest [1]. Data from normal subjects have suggested that a mean pulmonary artery pressure in excess of 20 mmHg is abnormal [2]. The 6th World Symposium on PH has proposed a threshold of > 20 mmHg to define PH and a requirement for a pulmonary vascular resistance of at least 3 Wood Units to define pre-capillary PH. Due to the non-specificity of symptoms, PH is often diagnosed late. Given the availability of therapies for specific forms of PH, there is increasing interest in better patient phenotyping and improving diagnostic rates with imaging [4]
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