Evaluation of pulmonary arterial pressure in patients with connective tissue disease‐associated pulmonary arterial hypertension by myocardial perfusion imaging

Background Pulmonary arterial hypertension (PAH) is a complex and severe complication of connective tissue disease (CTD). We aimed to evaluate the application value of myocardial perfusion imaging (MPI) in evaluating CTD‐associated PAH (CTD‐PAH). Methods We retrospectively included 88 patients who were diagnosed with CTD between January 2018 and December 2020 at our hospital. Fifty‐eight patients had PAH and were included into the CTD‐PAH group. Thirty patients without PAH were included in the control group. All patients received routine physical examination, biochemical tests and cardiac function evaluation, right heart catheterization (RHC), and 99m Tc‐MIBI MPI. PAH patients were divided into the mild, moderate, and severe PAH group according to their mean pulmonary artery pressures by RHC. Pearson correlation analysis was used to calculate the correlation between the right ventricle target/background (T/B) and right ventricle stroke volume (RV‐SV), total pulmonary resistance (TPR), pulmonary vascular resistance (PVR), mean pulmonary arterial pressure (mPAP), 6‐minute walk distance (6‐MWD), and N‐terminal B‐type natriuretic peptide (NT‐proBNP). The ROC curves of T/B and pulmonary artery pressure classification were plotted and the sensitivity and specificity of T/B in diagnosing PAH of different severities were analyzed. Results The analysis of correlation revealed that T/B correlated negatively with 6‐MWD and positively with NT‐proBNP and exhibited good positive correlation with mPAP, TPR, and PVR by RHC and negative correlation with RV‐SV. T/B was of the most diagnostic value for severe PAH, and its correlation with severe PAH was stronger than that with mild PAH and moderate PAH. Conclusions Target/background is a noninvasive method that can simultaneously evaluate pulmonary arterial pressure and myocardial perfusion of CTD‐CHD patients and is particularly of relatively high value for severe PAH patients.