INTRODUCTION
Pulmonary hypertension (PH) is a pathophysiological disorder, which may result from multiple cardiovascular and respiratory diseases. According to ESC/ERS Guidelines for PH in 2022, PH can be classified into two main subtypes: pre-capillary PH (pulmonary arterial wedge pressure (PAWP) ≤15 mmHg) and post-capillary PH (PAWP >15 mmHg). Pre-capillary PH is usually related to pulmonary arterial hypertension, thrombo-embolic PH, or PH due to lung disease or hypoxia, while postcapillary is mainly associated with heart failure (HF) or valvular heart diseases, and the two PH subtypes require different therapeutic strategies.[1] The current guidelines on PH recommend the invasive measurement of PAWP using right heart catheterization (RHC). However, when distinguishing pre- from post-capillary PH, except for PAWP threshold, the patient phenotype and echocardiographic findings including left atrial (LA) volume, are also needed to be considered[1].
Echocardiography is an importance modality in the assessment of patients with suspected or known PH. Also, it is recommended for the non-invasive diagnostic assessment of suspected PH, especially in patients with lung disease[1]. Besides, it had been proved that echocardiography had become an effective alternative method to invasive cardiac catheterization to help evaluate hemodynamic like PAWP and pulmonary vascular resistance (PVR) [2-4]. In previous studies, echocardiographic parameters could be used to accurately differentiate pre- and post- capillary PH, such as echocardiographic pulmonary to LA ratio (ePLAR), echocardiographic pulmonary to LA global strain ratio (ePLAGS), the body surfaced area–indexed left atrial minimum volume (LAVImin) and so on[5-9]. However, the software above used for evaluating LA volume and strain were not specifically dedicated to 3D left atrial measurements.
Recently, commercial software specially used to evaluate left atrial function has been applied in clinical practice, including 4D auto LA quantification analysis (LAQ). 4D auto LAQ is a LA analysis technique that uses 3D volume data to determine the LA volume of different periods in diastole as well as LA longitudinal and circumferential strains. It was reported that it had the advantages of high sensitivity, reproducibility and accuracy[10], and it was applied to multiple clinical diseases, such as patients with arrhythmia, the high risk of thromboembolism, type 2 diabetes, heart failure and so on[11-14]. There are no studies published about LA function assessed by 4D auto LAQ for distinguishing pre- from post-capillary PH. The purpose of this study was to investigate the value of LA volume and strain by 4D LAQ for differentiating pre- and post-capillary PH, and compare with ePLAGS.