Transcatheter Implantation of Intravascular Stents for Postoperative Residual Stenosis of Peripheral Pulmonary Artery Stenosis

Abstract

This is a prospective study of transcatheter implantation of 11 intravascular stents in 7 patients with status/post (S/P) surgical correction of major cardiovascular lesions. The safety and efficacy of balloon-expandable stents for treatment of peripheral pulmonary artery stenosis (PPAS) is evaluated and analyzed. Although the transcatheter implantation of intravascular stents has been reported as a possible treatment for stenotic peripheral pulmonary arteries, the results of intermediate follow-up studies on patients with S/P surgical correction for residual PPAS need to be evaluated. From June 1998 to December 2001, a total of 15 patients with PPAS having S/P surgery for major cardiovascular lesions were enrolled in this study. Eight of them had redo surgery after complete evaluation and the other 7 patients who might be at higher risk of mortality or morbidity from redo surgery, underwent transcatheter implantation of stents to dilate significant PPAS. Tetralogy of Fallot, S/P total correction, was done in 6 and transposition of great vessels, S/P Jatene operation, was done in 1. There were 10 stents (P 308 Palmaz stent ×8 and Intrastent™ ×2) implantation for 10 sites of the stenotic PPAS in these 7 patients, who were aged from 3.6 to 17.3 (10.1 ±5.6) years and had body weights ranging from 17 to 72.5 (37.1 ±23.0) kg. The narrowest diameter of the stenotic peripheral pulmonary arteries and pressure gradients across the stenosis were measured before and after implantation of stents. A follow-up catheterization and pulmonary angiography was performed 1 year later to evaluate the intermediate efficacy of stents implantation. All the stenotic peripheral pulmonary arteries of these 7 patients had a significant reduction of pressure gradients immediately after the procedure. The narrowest mean diameter of pulmonary arteries increased from 6.7 ±3.4 to 11.3 ±3.0 mm (p<0.001), and the mean pressure gradient dropped from 31 ±9.9 to 11.4 ±4.6 mm Hg (p<0.001). The follow-up catheterization 1 year later revealed a persistent effect in all but 1 patient. Only a young male presented with a recurrent stenosis with a pressure gradient of ≥20 mm Hg, which was relieved by redilation with implantation of another stent. There was no immediate or intermediate complication. Transcatheter stent implantation for treatment of a significant residual PPAS after surgical correction of complicated congenital heart disease is a safe and effective procedure. Since children are growing with age, a long-term follow-up study to evaluate the effects and possible problems of stent implantation is mandatory.