Continual Improvement in Pressure Gradient at the Lesion after Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Hypertension.

BACKGROUND Lung injury is a serious complication of balloon pulmonary angioplasty (BPA) for chronic thromboembolic pulmonary hypertension (CTEPH). Selecting a smaller balloon might minimize the occurrence of lung injury, however, it could also increase the risk of restenosis. METHODS We analyzed the first target lesions in the initial BPA procedure in 34 consecutive patients with CTEPH. We measured proximal pressure with a guiding catheter, and distal pressure with a pressure wire. We retrospectively investigated pressure gradients at the lesions before and immediately after the initial dilation with a smaller balloon, and before the second procedure. RESULTS The proximal pressure decreased, and the distal pressure increased immediately after the initial balloon dilation. The pressure gradient at the lesion significantly diminished by the second procedure (from 26.4 ± 10.7 to 18.2 ± 9.9 mmHg, p < 0.001) without a serious complication. The residual pressure gradient had further diminished (to 9.8 ± 6.5 mmHg, p = 0.02) until the second procedure. The reduction in pressure gradient at the lesion from immediately after the initial balloon dilation to the second procedure was positively correlated with both the baseline mean pulmonary arterial pressure (r2 = 0.23, p = 0.004) and residual pressure gradient immediately after the initial balloon dilation (r2 = 0.58, p < 0.001). CONCLUSIONS The residual pressure gradient at the lesion diminished continually after dilation with a smaller balloon. This strategy could safely decrease pulmonary arterial pressure. It would be reasonable to dilate the lesions sequentially in two procedures.