Alteration in Distribution of Pulmonary Blood Flow

Abstract

Physiological evaluation of lung function including distribution of perfusion and ventilation with xenon-133 was conducted in seven subjects, ages 9 to 49 years, with homozygous alpha1-antitrypsin deficiency. Four subjects, ages 36 to 49, had mildly impaired air flow rates, hypoxemia, increased alveolar-arterial oxygen gradients, and decreased carbon monoxide diffusing capacity. Altered distribution of pulmonary perfusion with loss of the normally occurring perfusion gradient from base to apex was present in these four as well as in a 14-year-old subject who was otherwise physiologically normal. The other two subjects, ages 9 and 12, were entirely normal. These findings suggest that pulmonary vascular bed is involved early in alpha1-antitrypsin deficiency, and obstructive airways disease appears later as shown by the temporal sequence of development of obstructive lung disease in these seven subjects.