Pulmonary arterial pressure assessment
The sPAP was calculated by peak tricuspid regurgitation velocity (TRV) with continuous-wave Doppler in the apical four-chamber view, using the simplified Bernoulli equation: 4 × (maximal TRV) 2 + right atrial pressure. Right atrial pressure was estimated in the subcostal view according to inferior vena cava (IVC) size and collapsibility following a normal sniff: An IVC diameter < 2.1 cm that collapsed >50% with a sniff suggested normal RA pressure of 3 mm Hg (range, 0–5 mm Hg), whereas an IVC diameter > 2.1 cm that collapsed < 50% with a sniff suggested a high RA pressure of 15 mm Hg (range, 10–20 mm Hg). In scenarios in which IVC diameter and collapse did not fit this paradigm, an intermediate value of 8 mm Hg (range, 5–10 mm Hg) might be used, or, preferably, other indices of RA pressure could be integrated to downgrade or upgrade to the standard or high values of RA pressure (5,11). The echocardiographic probability of pulmonary hypertension was classified as (1) low: peak TR velocity ≤ 2.8 m/s, (2) intermediate: peak TRV 2.9-3.4 m/s, without other echo PH signs and (3) high: peak TRV 2.9-3.4 m/s with other echo PH signs and >3.4 m/s, based on the 2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension (12).