We investigate, if laser balloon angioplasty (LBA) could achieve duct patency and devitalize its closure mechanism to replace shunt surgery for infants with pulmonary atresia.
11 newborns lambs (3.2-6.2 kg; 2-5 days) underwent cardiac catherization. After aortograms showed functional closure, antegrade LBA of the duct (balloon diameter 3mm) was performed (20 sec Nd:YAG laser irradiation of the wall, 15-20 sec cooling with balloon inflation.) Irradiance was 0 to 26 W/cm2. Aortograms were repeated for up to 60 minutes. In 5 animals we measured temperatures of the ductal intima, media and adventitia. Histology was obtained after sacrifice.
Angioplasty without lasing was ineffective, LBA achieved duct angiography the mean duct diameter was 2.8±0.7 mm. No complications occurred. Maximal tissue temperatures ranged between 90-1100 with a decline to 60°C after 18±5s. Histology showed clot formation and cell damage, but a relatively intact wall structure.
Laser balloon angioplasty reproducible generated a shunt persistent for short term observation. Long term survival experiments are underway.
Radtke W, Anderson RR, Guerrero L, Gregory KW, Parrish JA, Laser Balloon Angioplasty of the Ductus Arteriosus for Paliative Shunting, Circulation (Suppl. II) 78:II-100, 1988.