Radiofrequency thermal angioplasty maintains arterial duct patency : an experimental study

Long-term maintenance of arterial duct patency by a catheter technique would be a valuable nonsurgical method of palliation for duct-dependent circulations. We used a new method: percutaneous radiofrequency thermal balloon angioplasty of neonatal lamb arterial ducts. Radiofrequency balloons 5 or 6 mm in diameter were introduced via the femoral vein of 32 neonatal lambs and inflated to 4 atm. In 28, a radiofrequency generator was used to heat the saline/contrast mixture in the balloon to 65 degrees C (n = 2), 75 degrees C (n = 2), 85 degrees C (n = 10), 100 degrees C (n = 8), and 120 degrees C (n = 6). In 4 lambs, angioplasty alone was performed. Lambs were recatheterized to assess patency at intervals up to 78 weeks. Immediate results showed the arterial duct to be patent in all cases, with a mean rise in systolic pulmonary artery pressure of 13 +/- 8 mm Hg and a mean rise in pulmonary artery oxygen saturation of 12 +/- 15%. With a mean follow-up of 45.7 +/- 28 weeks, 3 of the 4 (75%) angioplasty alone ducts closed, but only 5 of the 28 (18%) radiofrequency-treated ducts (P < .05). The mean rise in oxygen saturation between the superior vena cava and the pulmonary artery was 7.6 +/- 7% at last follow-up. Follow-up angiography of the arterial ducts showed the development of stenoses in all patent ducts. Radiofrequency thermal balloon angioplasty leads to long-term arterial duct patency in lambs in > 80% of the treated group and is significantly more effective than balloon angioplasty alone.