Morphologic Changes of the Pulmonary Arteries after Stent Implantation on Branch Pulmonary Artery Stenosis: Impact of Pulmonary Insufficiency

ABSTRACT

PURPOSE: Intravascular stent implantation for the treatment of postoperative branch pulmonary artery(PA) stenosis has been used successfully. However, the cross sectional area of contralateral branch PA does not regress in spite of the successful dilation of the stenotic branch PA after stent implantation. We analyzed the morphologic and hemodynamic factors on the size of branch PA after successful stent implantation. METHODS: The subjects in our study were 23 children who had undergone stent implantaion from Jan. 1995 to Jul. 2002 in the Division of Yonsei Pediatric Cardiology. We evaluated the cross sectional area index(CSAI) of branch PA before and after stent implantation at follow-up catheterization. We also investigated factors such as residual pulmonary stenosis, pulmonary regurgitation(PR), systolic pressure of right ventricle, and lung perfusion scan. RESULTS: The CSAI of the RPA without stenosis changed from mean 238+/-17 mm2/BSA to mean 249+/-20 mm2/BSA(P=0.47), but didn't regress. The CSAI of the LPA with stenosis was increased effectively by stent implantation from the mean 102+/-12 mm2/BSA to mean 125+/-11 mm2/BSA(P< 0.05). At follow up after stent implantation, the CSAI of PA is correlated with the residual PR fraction after stent implantation. CONCLUSION: In a group with increased residual PR, CSAI of RPA was found to be significantly increased between the pre- and post-stages of stent implantation. So, we suspect that the pulmonary regurgitation remaining after right ventricle outlet tract(RVOT) dilatation surgery is correlated with the increase in CSAI of RPA.