Regional pulmonary blood flow in mitral disease studied by xenon radiospirometry

Regional lung perfusion was measured in the sitting position by 4 external detectors after intravenous injection of 133Xe in 24 patients with mitral valve disease and in 8 people with no cardiopulmonary disease acting as normal controls. Right- and left-sided heart catheterization was carried out on the patients on the following day. Mitral valve stenosis was found in 9, mitral valve regurgitation in 8, and both stenosis and regurgitation in the remaining 7. Regional lung perfusion in the normal people fell linearly from the basal to the apical sections of the lungs. The perfusion distribution in patients with mitral valve disease and a pulmonary capillary vein (PCV) pressure lower than 15 mmHg (2-0 kPa) did not differ significantly from that of the controls. A redistribution of the regional perfusion, with an increase in the apical perfusion and a fall in the basal perfusion of the lungs, was seen in patients with a raised PCV pressure. The hyperperfusion of the apical lung sections correlated with the mean pressure in the pulmonary artery (r=+0-795, P less than 0-001), while the basal hypoperfusion correlated with the PCV pressure (r=0-842, P less than 0-001). The PCV pressure can be predicted with an exactitude of +/- 7 mmHg (0-9 kPa) (95% confidence limits). Neither the cardiac index nor the pulmonary vascular resistance correlated with the changes in perfusion. Xenon radiospirometry is a rapid and reliable method for evaluating PCV pressure before or after operation in patients with mitral valve disease.