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).