RESUMO
Objective:To investigate the correlations between perfused lung volumes, visual scores (using perfusion SPECT/CT) and right-heart catheter (RHC) hemodynamic parameters in patients with chronic thromboembolic pulmonary hypertension (CTEPH).Methods:A total of 51 consecutive CTEPH patients (17 males, 34 females, age (59±12) years) in the First Affiliated Hospital of Guangzhou Medical University between March 2015 and July 2019 were retrospectively analyzed. All patients underwent lung perfusion SPECT/CT imaging and RHC examinations. Perfused lung volumes were determined using threshold-based (15%-85%) segmentation. Visual semiquantitative scoring in each lung segment was performed using Begic method. RHC hemodynamic parameters including pulmonary artery systolic pressure (PASP), pulmonary arterial diastolic pressure (PADP), mean pulmonary artery pressure (mPAP), pulmonary arteriolar wedge pressure (PAWP), pulmonary vessel resistance (PVR), cardiac output (CO), cardiac index (CI) were recorded. Spearman correlation analysis was used to evaluate the correlations between perfused lung volumes, visual scores and hemodynamic parameters.Results:There were significant correlations between perfused lung volumes (30%-70% threshold) and mPAP ( rs values: from -0.414 to -0.302, all P<0.05). Among them, perfused lung volumes under the threshold of 40% and 45% were moderately correlated with mPAP ( rs values: -0.414, -0.412, both P<0.05). Perfused lung volume (40% threshold) was moderately negatively correlated with PASP, PADP ( rs values: -0.402, -0.440, both P<0.05), and slightly negatively correlated with PVR ( rs=-0.352, P<0.05). Visual scores were slightly positively correlated with the PADP ( rs=0.311, P<0.05), while there was no correlation between visual scores and other RHC hemodynamic parameters ( rs values: from -0.201 to 0.275, all P>0.05). Conclusion:Perfused lung volumes based on threshold-based segmentation in lung perfusion SPECT/CT imaging can accurately reflect hemodynamic status and may provide useful information for severity assessment of CTEPH.