Background: Control of distal pulmonary artery (PA) pressure and flow is a critical step in palliating infants with complex congential heart disease. Surgical procedures to protect or isolate the pulmonary circulation carry significant risk and can be unpredictable. Interventional control of pulmonary pressure/flow with an intravascular device (band) could reduce risk and improve regulation of pulmonary flow.
Methods: Internal pulmonary bands were created from woven nitinol to create an internal orifice estimated to reduce distal pulmonary arterial pressure by 50%. Two designs were tested, a single eccentric lumen and two symmetrical lumens. The devices were approximately 7-mm long and the external diameter varied to suit the pulmonary arterial lumen size. A total of 15 devices were implanted in seven lambs with a stented ductus arteriosus to create high pulmonary pressure/flow. Four lambs were followed with devices and stent in place for a mean of 37 +/- 13 days.
Results: Fourteen of 15 devices were successfully implanted. One was acutely removed since the size was too large. Both device designs created greater than a 50% reduction in distal pulmonary pressure. Main PA pressure was 70/38, mean 50 +/- 13 mm Hg, and distal PA pressure 25/16, mean 20 +/- 7 mm Hg (P < 0.05). Angiography demonstrated protection of the internal banded pulmonary segments from overcirculation. Late follow-up showed that the device lumen(s) remained patent. Histology showed the vessel media to be intact but there was intimal proliferation where the device approximated the wall. There were no thrombotic emboli detected.
Conclusion: Percutaneous internal banding of the pulmonary arteries was feasible and successful in lambs with high pulmonary flow/pressure analogous to infants with complex congenital heart disease.
(c) 2007 Wiley-Liss, Inc.