Diameters of the pulmonary arteries and veins as an indicator of bilateral and unilateral pulmonary blood flow in patients with congenital heart disease.

Abstract

This study was done to clarify which diameter, that of the pulmonary arteries (PAs) or that of the pulmonary veins (PVs), more precisely reflects pulmonary blood flow (PBF) bilaterally and unilaterally. To evaluate bilateral PBF, we studied 15 consecutive patients with Kawasaki disease as normal patients and 30 patients with tetralogy of Fallot who received cardiac catheterization. To evaluate unilateral PBF, 20 patients with various congenital heart diseases undergoing cineangiography and lung perfusion scintigraphy were studied. The diameter of PA was measured immediately proximal to the origin of the first lobar branches bilaterally, and right PA area, left PA area, PA area (mm2), and PA index (mm2/m2) were calculated. The diameter of PV was also measured distal to the junction with the left atrium. Right PV area, left PV area, PV area (mm2), and PV index (mm2/m2) were calculated from these diameters. Pulmonary blood flow (PBF) was obtained by the Fick method during catheterization. To evaluate unilateral PBF, PBF was divided into right and left PBF according to the right/left perfusion ratio measured by lung perfusion scintigraphy. Evaluation of bilateral PBF was as follows: in normal patients, PA and PV areas were correlated with body surface area (r = 0.88, p = 0.0001 and r = 0.93, p = 0.0001); PA index and PV index ranged from 248 to 436 (mean = 343) mm2/m2 and from 346 to 595 (mean = 466) mm2/m2, respectively, and were constant irrespective of body surface area; PA and PV areas were correlated with PBF in normal patients, as well as in patients with tetralogy of Fallot. There was a better correlation between PV area and PBF than between PA area and PBF in normal patients, as well as a significantly better correlation in patients with tetralogy of Fallot. Evaluation of unilateral PBF was as follows: right PV area was correlated with right PBF (p = 0.0002), while right PA area was not; left PV area and left PA area were correlated with left PBF; right/left PV area ratio was correlated with the right/left perfusion ratio with better agreement than right/left PA area ratio. Our data suggest that the size of PVs in patients with congenital heart disease may be more useful than the size of PAs to indicate bilateral and unilateral PBF than the size of PAs. Differences in PV area of each lung may be a suitable indicator of discrepancy in blood flow to each lung.