EXPERIENCE WITH THE PALMAZ STENT IN THE P ULMONARY-ARTERY STENOSIS

Introduction and objectives. Since 1989, the balloon expandable Palmaz stent (Johnson & Johnson Interventional Systems) has been used for th e treatment of congenital heart disease. This study reports the result s and the technique used for its implantation in native and post surgi cal retraction pulmonary branch stenosis. Materials and methods. From february 1995 to june 1996, we have perfomed this technique in II symp tomatic children/adolescents with pulmonary branch stenosis, the mean age was II +/- 2 years. Fourteen procedures were made and 16 stents we re implanted. The mean condition of the patients was: 7 with tetralogy of Fallot after a previous complete correction, 1 with Noonan syndrom e and a surgically corrected atrial septal defect, 1 with pulmonary tr unk aneurysm and a previous surgical correction for pulmonary valve an d branch stenosis, 1 with pulmonary atresia and an intact septum who u nderwent a surgical valvotomy and posterior percutaneous valvuloplasty with a good ventricular development, and final was a tricuspid atresi a with a previous Waterston anastomosis which produced a stenosis at t he right pulmonary branch who underwent a modified Fontan operation wi th the result of a severe stenosis at the medial and inferior right pu lmonary artery. The branch ostium was affected in five cases, and in o ne case with diffuse hypoplasia of the right branch, the stenosis was at both sites. The stenosis was native in nine cases and post surgery in the other five (2 Waterston, 1 Blalock-Taussig, 1 Fontan). We used the right and/or left femoral vein in all cases except two, in which W e used the internal jugular vein. We followed the technique reported b y the Boston-Houston experience, with an extra stiff guide and Mullins sheath towards the site of the stenosis. Results. The procedure was e ffective in all cases except one. The mean pulmonary branch and balloo n diameter was 11 +/- 3 mm and 14 +/- 2 mm, respectively, rate 1.2. Th e stenosis diameter rose from 4.8 +/- 1 to 11 +/- 2 mm (p < 0.001) wit h a percentage fall from 63 +/- 5 to 2 +/- 1% (p < 0.001). The pressur e gradient fell from 30 +/- 5 to 5 +/- 1 mmHg (p < 0.001) and the righ t ventricle systolic pressure fell from 77 +/- 6 to 48 +/- 3 mmHg (p < 0.01). The mean follow-up was 10 +/- 3 months, a symptomatic and pulm onary perfusion improvement was seen. After 8 +/- 4 months, we evaluat ed six patients/nine stents with angiography, and we excluded thrombos is, aneurysms and occlussion of lobar or segmental branches. One case had a proximal stent re-stenosis as it did not cover the whole stenosi s, so a new stent was implanted. Three patients/four stents underwent redilatation getting a slightly higher diameter than previously. Compl ications. One patient had a stent migration and he underwent surgical stent retrieval. Conclusions. Implantation of the Palmaz stent; is a u seful procedure for the treatment of native or post-operative pulmonar y stenosis. It is possible to apply it to hypoplastic and ostial pulmo nary stenosis. We confirm the effectiveness of redilatation at mid ter m.