BACKGROUND: Nineteen patients (mean age, 7.6 months) with a percent wall thickness of more than 33% in the small pulmonary arteries were found to have extremely thickened media. Based on our findings, a criterion of operative indication is proposed. METHODS: The percentage of extremely thickened media of small pulmonary arteries for all pulmonary arteries was determined on microscopic lung sections and was introduced as an index for operative indication. RESULTS: Operative repair was performed in 16 patients: 9 died intraoperatively and 7 survived more than 12 months. In 4 of 5 patients that had pulmonary artery banding, medial hypertrophy remained despite pulmonary artery banding. Operative repair also had no positive effect. In operative and late deaths and in survivors without a decrease of pulmonary arterial pressure, the percentage of extremely thickened media of small pulmonary arteries was shown to be more than 10%, whereas in 5 survivors and 1 operative death with a significant postoperative decrease of pulmonary arterial pressure, the value was less than 7%. CONCLUSIONS: If a patient has less than 7% of small pulmonary arteries with extremely thickened media, operative repair is likely to be effective. When the value is higher than 10%, not only operative repair but also pulmonary artery banding cannot be recommended because of ineffectiveness and hazard.
BACKGROUND: Nineteen patients (mean age, 7.6 months) with a percent wall thickness of more than 33% in the small pulmonary arteries were found to have extremely thickened media. Based on our findings, a criterion of operative indication is proposed. METHODS: The percentage of extremely thickened media of small pulmonary arteries for all pulmonary arteries was determined on microscopic lung sections and was introduced as an index for operative indication. RESULTS: Operative repair was performed in 16 patients: 9 died intraoperatively and 7 survived more than 12 months. In 4 of 5 patients that had pulmonary artery banding, medial hypertrophy remained despite pulmonary artery banding. Operative repair also had no positive effect. In operative and late deaths and in survivors without a decrease of pulmonary arterial pressure, the percentage of extremely thickened media of small pulmonary arteries was shown to be more than 10%, whereas in 5 survivors and 1 operative death with a significant postoperative decrease of pulmonary arterial pressure, the value was less than 7%. CONCLUSIONS: If a patient has less than 7% of small pulmonary arteries with extremely thickened media, operative repair is likely to be effective. When the value is higher than 10%, not only operative repair but also pulmonary artery banding cannot be recommended because of ineffectiveness and hazard.