RV–pulmonary arterial coupling

TAPSE/PASP · TAPSE (M-mode, lateral tricuspid annulus) divided by PASP from the TR jet + RAP

Normal range & thresholds

>0.55 mm/mmHg coupled. <0.55 is a category-A sign in the ESC/ERS echocardiographic probability of PH ^[8]; <0.31 identified invasive RV–PA uncoupling (Ees/Ea <0.805) in severe PH ^[77] and was strongly prognostic in heart failure ^[52].

Pathophysiology

TAPSE approximates RV contractile function and PASP its afterload; their ratio is a length–force analogue of Ees/Ea for the right ventricle. The RV tolerates volume but not pressure: when afterload rises faster than contractility can adapt, coupling fails, the RV dilates and interdependence reduces LV filling ^[77].

Raised by

• Normal pulmonary pressure with preserved RV function

Lowered by

• Pulmonary hypertension of any group, RV failure, acute PE

Technique & pitfalls

• Complete TR envelope from multiple windows; measured (not assumed) RAP; aligned TAPSE ^[3].

Pseudo-change & artefact

• Underestimated PASP in torrential TR (falsely high ratio); post-cardiac-surgery TAPSE (falsely low).

Treatment thresholds

• Supports referral for right-heart catheterisation and PH risk stratification ^[8]; a key marker in transcatheter tricuspid candidacy and HF prognosis ^[6,52].

Next step

• RV free-wall strain (card 62), PVR estimate (card 66), right-heart catheterisation.

Drugs

Pulmonary vasodilators in group 1 PH, decongestion in group 2; never pulmonary vasodilators in group 2 PH ^[8].

Reversibility

Improves in treatment responders and after relief of left-sided disease.