Clinical research on echocardiographic screening for pulmonary hypertension: TRV >2.8 m/s and mPAP >20 mmHg

In 2022, the European Society of Cardiology (ESC) and the European Respiratory Society (ERS) revised the diagnostic criteria for pulmonary hypertension (PH) from mean pulmonary arterial pressure (mPAP) ≥25 mmHg to >20 mmHg. However, the echocardiographic standards [the tricuspid regurgitation velocity (TRV) >2.8 m/s] have not been updated. This study aims to optimize the reference value of TRV, and evaluate the discriminatory efficacy of TRV in pulmonary artery pressure grading.

Patients suspected of having PH underwent both ultrasound (US) and right heart catheterization (RHC) examinations. The TRV and tricuspid regurgitant pressure gradient (ΔPTR) were measured via US. Right atrial pressure (RAP) was estimated via US by related parameters of the inferior vena cava. Subsequently, the systolic pulmonary artery pressure measured by ultrasound (US-sPAP) was equivalent to RAP + ΔPTR. RHC recorded the systolic pulmonary artery pressure (RHC-sPAP) and mean pulmonary artery pressure (RHC-mPAP). The reference standards for TRV and US-sPAP were established using RHC-mPAP >20 mmHg or RHC-mPAP ≥25 mmHg as diagnostic criteria for PH, respectively. Patients were classified into mild (20 mmHg < mPAP ≤30 mmHg), moderate (30 mmHg < mPAP ≤40 mmHg), and severe (mPAP >40 mmHg) and the reference criteria for TRV and US-sPAP were then determined accordingly.

A total of 257 patients were included in this study, comprising 218 patients with mPAP >20 mmHg and 192 patients with mPAP ≥25 mmHg. There was no statistically significant difference between US-sPAP and RHC-sPAP (P=0.969), and the correlation was significant (r=0.793, P<0.001). Bland Altman analysis showed high consistency (intraclass correlation coefficient =0.762). When mPAP >20 mmHg was used as the threshold for diagnosing PH, the optimal cut-off values for US-sPAP, TRV, and RHC-sPAP were 37 mmHg, 2.9 m/s, and 41 mmHg, respectively [areas under the curve (AUCs) 0.926, 0.936, 0.981, accuracies 89.9%, 89.5%, 90.3%]. The cut-off values for distinguishing mild/moderate elevation of mPAP were 60 mmHg, 3.7 m/s, and 57 mmHg, respectively (AUC 0.903, 0.900, 0.988, accuracy 81.3%, 80.9%, 94.2%). The cut-off values for distinguishing moderate/severe elevation were 68 mmHg, 4.0 m/s, and 72 mmHg (AUC 0.881, 0.882, 0.971, accuracy 81.3%, 82.9%, 91.1%), respectively. When mPAP ≥25 mmHg was used as the diagnostic threshold for PH, the AUCs for US-sPAP, TRV, and RHC-sPAP were 0.931, 0.933, and 0.990, respectively, with cut-off values of 45 mmHg, 3.4 m/s, and 43 mmHg, and accuracies of 86.8%, 80.5%, and 96.5%.

Utilizing a TRV threshold of >2.8 m/s for echocardiographic assessment aligns more closely with the 2022 guidelines (mPAP >20 mmHg) but demonstrates poor correlation with the 2015 guidelines (mPAP ≥25 mmHg). Additionally, US-sPAP ≥37 mmHg can serve as a reliable criterion for assessing PH.