Pulmonary venous wedge pressures accurately predict pulmonary arterial pressures in children with single ventricle physiology

We investigated the relationship between pulmonary venous wedge and pulmonary arterial pressures in patients with single ventricle physiology. This relationship has been studied in other cardiac conditions but not in this unique group of patients. We made 60 paired measurements from one or both lungs in 40 patients, and divided the patients into three groups. Group 1 consisted of patients whose pulmonary blood supply was via an aortopulmonary shunt (n = 14), group 2 included patients with a bidirectional Glenn anastomosis (n = 20), and group 3 included patients with a pulmonary arterial band (n = 6). Venous wedge pressure estimated arterial pressure within 3 mmHg in 59 of 60 paired measurements. Plots of the difference between pulmonary artery and pulmonary venous wedge pressures versus the mean showed excellent correlation, with a mean difference of approximately 1 for group 1 (mean difference, -0.15 +/- 1.3 mmHg) and group 2 (mean difference, 0.52 +/- 1.12 mmHg). The relationship was poor in group 3 (mean difference, -2.00 +/- 4.80 mmHg) but was much better with the exclusion of the one outlying patient in whom pulmonary venous wedge pressure significantly overestimated pulmonary arterial pressure (mean difference, -0.33 +/- 2.07 mmHg). We conclude that pulmonary venous wedge pressure accurately estimates pulmonary arterial pressure in patients palliated for single ventricle physiology, but care must be taken in patients with a pulmonary arterial band.