Pulmonary hypertension

Echocardiographic probability, the left-heart clues to group 2, and RV–PA coupling for prognosis.

Numbers to remember

• Haemodynamic definition: mPAP >20 mmHg; pre-capillary if PAWP ≤15 and PVR >2 WU ^[8,180]
• TR velocity >3.4 m/s = high probability; 2.9–3.4 m/s = intermediate, and high if other signs are present ^[8]
• Other signs must come from two different categories (ventricles, PA, IVC/RA) ^[8]
• TAPSE/PASP <0.55 mm/mmHg is an ESC ventricular sign; lower values mark RV–PA uncoupling ^[8,77]

Questions echo must answer

Echo does not diagnose PH. It assigns a probability that decides whether right-heart catheterisation is needed ^[8]. It also suggests the group and measures the RV's response, which is what determines prognosis ^[3,8].

1. ProbabilityPeak TR velocity plus signs from three anatomical categories ^[8].
2. GroupLeft-heart disease (group 2) versus pre-capillary PH: LA size, E/e′, LA strain, LV hypertrophy and valve disease ^[8,99].
3. RV adaptationTAPSE, S′, FAC, RV strain, TAPSE/PASP, RA area, pericardial effusion ^[3,8,52,77].
4. Shunts and causesASD, sinus venosus defect, anomalous pulmonary venous return, PDA; congenital heart disease ^[175].

Acquisition protocol

1. RV inflow, RV-focused, PSAX, subcostalMeasure TR peak velocity from every window and keep the best-aligned, well-defined envelope. Use agitated saline to enhance a weak signal ^[3].
2. RV-focused A4CRV/LV basal ratio, RA area, TAPSE, S′, FAC and RV free-wall strain ^[3].
3. PSAX-PMLV eccentricity index in systole and diastole ^[166].
4. PSAX-AV / RVOTRVOT PW: acceleration time, mid-systolic notching, VTI. PA diameter. PR early-diastolic velocity ^[8,47].
5. SubcostalIVC diameter and collapse ^[50]. Look for pericardial effusion.
6. Left heartLAVI, E/e′, LA strain, LV mass and valve disease ^[2,99].
7. ShuntColour and saline across the IAS; look for the pulmonary veins ^[175].
8. DerivedCalculate PASP, TAPSE/PASP, and PVR estimate (Abbas: TRV/VTI-RVOT) ^[49].

• TR velocity (best window)
• RV/LV ratio, LVEI
• RVOT AcT and notching
• PR early velocity, PA diameter
• IVC and RA area
• TAPSE, S′, FAC, TAPSE/PASP
• Left-heart clues (group 2)
• Shunt excluded
• Probability: low / intermediate / high

Diagnosis & severity

ESC/ERS 2022 echocardiographic probability ^[8]

*Signs from at least two categories:

• A. Ventricles: RV/LV basal diameter or area ratio >1.0; flattened septum (LVEI >1.1); TAPSE/PASP <0.55 mm/mmHg.
• B. Pulmonary artery: RVOT AcT <105 ms and/or mid-systolic notching; early-diastolic PR velocity >2.2 m/s; PA diameter >aortic root diameter or >25 mm.
• C. IVC and RA: IVC >21 mm with reduced inspiratory collapse (<50% with a sniff, <20% quiet breathing); RA area >18 cm² at end-systole.

Prognostic markers ^[8]

RA area, pericardial effusion, TAPSE/PASP and RV function are part of the ESC risk assessment in PAH.

Thresholds that change management

• High probability, or intermediate with risk factors (connective tissue disease, previous PE, family history, portal hypertension) → refer to a PH centre for right-heart catheterisation ^[8].
• Features of left-heart disease (LA enlargement, raised E/e′, atrial fibrillation, LV hypertrophy) → treat the left heart first. Catheterise only if pre-capillary PH is suspected ^[8].
• 3–6 months after PE with dyspnoea and intermediate or high probability → V/Q scan to screen for CTEPH ^[8,124].
• Portal hypertension or liver transplant work-up → echo screening for portopulmonary hypertension ^[204].

Pitfalls & mimics

• Underestimation from poor alignment and weak signals; overestimation from counting noise or chordal artefact.
• RAP from the IVC is unreliable in ventilated patients and athletes (a large IVC in athletes) ^[3].
• High-output states (anaemia, cirrhosis, AV fistula, thyrotoxicosis) raise the TR velocity without raised PVR.
• Pulmonary stenosis or RVOT obstruction raises RV systolic pressure without PH. Check the pulmonary valve before calling PASP.