Aims: Quantification of linear lung ultrasound (LUS) artefacts (B-lines) represents a novel, non-invasive approach to assess pulmonary congestion. We investigated the relationship between the number of B-lines (vertical artefacts arising from the pleural line) and intracardiac pressures.
Methods and results: Prior to scheduled right heart catheterization (RHC), 100 subjects underwent LUS of eight zones. A reviewer blinded to the haemodynamic data quantified the number of sonographic B-lines. Of 92 subjects who completed RHC, 79 had adequate LUS data of all zones [median age 61 years, 26 women, median left ventricular ejection fraction (LVEF) 58%, 35 with history of heart failure; 22 postcardiac transplantation]. The number of B-lines correlated with measured right atrial (r = 0.32), pulmonary artery diastolic (PADP) (r = 0.34), mean pulmonary artery (mPAP) (r = 0.43), pulmonary artery systolic (PASP) (r = 0.48) pressures, and pulmonary vascular resistance (PVR) (r = 0.51) (P < 0.005 for all), but not with pulmonary capillary wedge pressure. There was a graded association between tertiles of B-line number and increasing PADP, mPAP, PASP, and PVR (P for trend ≤0.001 for all). Each additional B-line was associated with an increase in PASP of 1 mmHg and an increase in PVR of 0.1 Wood units. These associations remained robust after multivariable adjustment (P = 0.002). Assessment of two inferior lateral zones resulted in similar correlations to the eight-zone method.
Conclusions: Easily obtainable, LUS may be useful in the estimation of right-sided cardiac pressures and PVR. Further evaluation of lung ultrasound as an adjunct to heart failure diagnosis, monitoring, and prognosis is warranted.