Pulmonary venous wedge pressure provides a safe and accurate estimate of pulmonary arterial pressure in children with shunt-dependent pulmonary blood flow.

OBJECTIVES

To compare two methods of pulmonary arterial pressure measurement in children with shunt-dependent pulmonary blood flow.

BACKGROUND

In children with shunt-dependent pulmonary blood flow, direct assessment of pulmonary arterial pressure requires passage of a catheter across the shunt. This can be technically difficult and dangerous. Use of the pulmonary venous wedge pressure offers an alternative but has not been validated in this patient population.

METHODS

We prospectively studied 18 children with shunt-dependent pulmonary blood flow. Pulmonary venous wedge pressure and directly measured pulmonary arterial pressures were independently assessed by two blinded cardiologists.

RESULTS

Directly measured mean pulmonary arterial pressure and pulmonary venous wedge pressure are closely correlated (R2 = 0.80, P < 0.01). Agreement between the two measures is improved at lower mean pressures with greater differences at higher pressures. For 20 of 24 ipsilateral measurements, pulmonary venous wedge pressure was > or = directly measured pulmonary arterial pressure. Pulmonary venous wedge pressure never underestimated pulmonary arterial pressure by more than 3 mm Hg.

CONCLUSIONS

Pulmonary venous wedge pressure provides a safe and accurate means of estimating pulmonary arterial pressure in children with shunt-dependent pulmonary blood flow. The slightly lower pressures seen on direct measurement compared with the reverse pulmonary vein may reflect impairment of flow across the shunt by the catheter.