S82 Using cardiac magnetic resonance imaging to assess cardiac geometry in the diagnosis of chronic thromboembolic disease and chronic thromboembolic pulmonary hypertension

• Published in: Thorax Vol. 76; no. Suppl 2; pp. A52 - A53
• Main Authors: McGettrick, M, Dormand, H, Brewis, M, Lang, NN, Johnson, M, Church, AC
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Thoracic Society 08.11.2021; BMJ Publishing Group LTD
• Subjects: Pulmonary arteries; Pulmonary hypertension; Thromboembolism; Under pressure: an update in pulmonary vascular disease; Veins & arteries
• ISSN: 0040-6376; 1468-3296
• DOI: 10.1136/thorax-2021-BTSabstracts.88

BackgroundCardiac magnetic resonance (CMR) imaging is the gold standard tool for evaluating the right ventricle (RV) in chronic thromboembolic disease (CTED) and chronic thromboembolic pulmonary hypertension (CTEPH). Ventricular septal flattening, reflecting RV pressure overload in idiopathic pulmonary arterial hypertension (IPAH) has been quantified using the eccentricity index (EI) with echocardiography and pulmonary artery distensibility (PAD) has been shown to correlate with pulmonary artery pressure. These have not been evaluated for use in CTEPH using CMR. We assessed them in the detection of CTED and CTEPH and correlated with haemodynamics.MethodsCMR and right heart catheterisation were performed on 30 patients with CTEPH and 20 sex-matched controls without resting pulmonary hypertension (10 patients with no thrombotic disease and 10 with CTED) at a national pulmonary hypertension centre. Mid-papillary short axis view was used to assess the eccentricity index at end-systole and end-diastole. Main PAD was measured using velocity-encoded CMR, perpendicular to pulmonary artery.ResultsEI at end-systole and end-diastole were significantly increased in CTEPH compared to controls (1.3 (0.5)vs1.0 (0.01); p≤0.01 and (1.22 (0.2)vs0.98 (0.01); p≤0.01, respectively). PAD was significantly reduced in CTEPH compared to controls (0.13 (0.1) vs 0.46 (0.23); p≤0.01). End-systolic EI and end-diastolic EI significantly correlated with pulmonary vascular haemodynamic indices, including mean pulmonary arterial pressure, cardiac output and with NTproBNP. End-systolic and End-diastolic EI correlated with exercise capacity as measured by 6-minute walk distance, and with pulmonary artery distensibility (R-value 0.8). Using ROC curves, an optimal threshold of 1.1 for both end-diastolic and end-systolic indices identified the presence of pulmonary hypertension. Both EI and PAD were able to differentiate the presence of CTED from normal.Abstract S82 Figure 1MRI indices in patients with no pulmonary vascular obstruction, CTED, proximal and distal CTEPHP-value = ANOVA*p = <0.01 **p = <0.05, ns = not significantA – Pulmonary Artery Distensibility, B – Systolic Left Ventricular EI, C – Diastolic Left Ventricular EIConclusionEI and PAD correlate with invasive haemodynamic indices and right ventricular function in CTEPH. These measures strengthen the ability of CMR to detect pulmonary hypertension and provide further justification for the use of CMR in investigation of chronic thromboembolic disease.