Perfusion lung scintigraphy in primary pulmonary hypertension.

15 cases of primary pulmonary hypertension were classified into two groups by patterns of perfusion lung scintigraphy. Perfusion scintigrams showed multiple, small, ill-defined defects (mottled + ve) pattern in eight cases, and the remaining seven cases had a normal (mottled - ve) pattern. The mean pulmonary arterial pressure in patients with a mottled pattern (54 +/- 10 mmHg) was higher than in those with a normal pattern (42 +/- 9 mmHg, p < 0.05). There were no significant differences between the two groups in right ventricular ejection fraction, partial pressures of oxygen in the arterial blood or alveolo-arterial oxygen difference. All the patients with a mottled pattern died within 2 years following the lung scintigraphy. There was a significant difference in the survival curves between the two groups. Although our statistical analysis must be evaluated with caution because of small numbers of patients it is suggested that perfusion lung scintigraphy is useful in assessing the prognosis in primary pulmonary hypertension.