• diagnosis
• echocardiography
• Pulmonary hypertension
• right heart catheterization
• tricuspid regurgitation velocity

Background. The diagnosis of pulmonary hypertension (PH) relies on the measurement of pulmonary artery pressures at right heart catheterization (RHC). Echocardiographic tricuspid regurgitation velocity (TRV) is a screening tool to define PH probability. While the latest guidelines reduced RHC threshold for PH diagnosis, TRV thresholds were left unchanged. We aimed to update TRV thresholds for PH probability according to the novel RHC criteria.
Methods. Patients undergoing RHC for suspected PH, prospectively enrolled at the University Hospital of Trieste (Italy) and Karolinska University Hospital (Sweden) constituted the derivation cohort. A retrospective cohort from Fondazione Toscana G. Monasterio (Italy) was used for external validation. All patients underwent echocardiography and RHC within a 6-hour window under stable clinical and therapeutical conditions.
Results. In the derivation cohort (n=400), 85% of patients had PH at RHC, with TRV showing high discrimination (AUC=0.81). However, only 68% of patients had intermediate or high PH probability by using the conventional 280 cm/s threshold, with a false-negative rate of 24%. In this cohort, the optimal threshold for low probability was 250 cm/s, with higher sensitivity (90% vs 76%) and 10% false-negative rate. In the validation cohort (n=1,348), 76% of patients had PH. In this cohort, the proposed 250 cm/s low probability threshold was confirmed to hold a very high sensitivity (97%), with a false-negative rate of 3%.
Conclusions. This large multicenter derivation-validation study supports lowering the TRV threshold from ≤280 cm/s to ≤250 cm/s to decrease the false-negative rate and missing referral to RHC in patients with suspected PH.