Haemodynamic correlation with lung biopsy findings in isolated ventricular septal defect with or without pulmonary hypertension.

Pulmonary hypertensive patients have been found to have greater morbidity and mortality from isolated ventricular septal defect closure than those pulmonary non-hypertensive patients. In this study, the author evaluated the relation between pulmonary artery muscularity and pulmonary artery pressure and resistance and compared the haemodynamic effects between normal and raised pulmonary artery pressure groups in isolated ventricular septal defect. The patients were divided into two groups, group-I (n = 14): pulmonary artery pressure of 50 mmHg or less than 50 mmHg, and group-II (n = 6): pulmonary artery pressure more than 50 mmHg. The group-II patients were further studied during cardiac catheterization by inhaling 100% oxygen for 15 minutes to detect any fall in pulmonary artery pressure. The patients whose pulmonary artery pressure did not drop were considered to have operative intervention after lung biopsy. The mean pulmonary artery pressure, right ventricular pressure and pulmonary vascular resistance in group-I and group-II were 26.9 +/- 7.0 mmHg, 44.0 +/- 2.5 mmHg, 2.2 +/- 0.6 units/m2 vs 84.2 +/- 20.7 mmHg, 100.5 +/- 7.0 mmHg, 10.0 +/- 0.9 units/m2, respectively (p < 0.001). The left to right shunt flow in group-I and group-II was 50.6 +/- 6.0% vs 44.0 +/- 8.6%, respectively and was not significantly different (p < 0.1). In the operated group (n = 17), pulmonary artery pressures ranged 20-110 mmHg, size of the VSD 7.5-11.5 mm, and pulmonary vascular resistance 1.7-8.2 units/m2. In isolated ventricular septal defect, when the pulmonary vascular change was reversible, there was a positive correlation both between the VSD size and the level of pulmonary arterial pressure (r = 0.94, p < 0.001) and between the pulmonary arterial pressure and pulmonary vascular resistance (r = 0.95, p < 0.001). Lung biopsy (n = 9) showed grade I Heath-Edward change in 6 cases (66.6%), grade II change in 1 case (11.1%), and grade III in 2 cases (22.2%). From these findings, when pulmonary vascular resistance is 8 units/m2 or more, operative indication should be determined on the basis of lung biopsy. Not only the gradings of pulmonary vascular changes, but the extent of vascular involvement and the duration of the lung exposure to the shunt anomally also need to be considered before surgery.