[Experience with Palmaz stent in pulmonary branch stenosis]

Since 1989, the balloon expandable Palmaz stent (Johnson & Johnson Interventional Systems) has been used for the treatment of congenital heart disease. This study reports the results and the technique used for its implantation in native and post surgical retraction pulmonary branch stenosis.

From february 1995 to june 1996, we have performed this technique in 11 symptomatic children/adolescents with pulmonary branch stenosis, the mean age was 11 +/- 2 years. Fourteen procedures were made and 16 stents were implanted. The mean condition of the patients was: 7 with tetralogy of Fallot after a previous complete correction, 1 with Noonan syndrome and a surgically corrected atrial septal defect, 1 with pulmonary trunk aneurysm and a previous surgical correction for pulmonary valve and branch stenosis, 1 with pulmonary atresia and an intact septum who underwent a surgical valvotomy and posterior percutaneous valvuloplasty with a good ventricular development, and final was a tricuspid atresia with a previous Waterston anastomosis which produced a stenosis at the right pulmonary branch who underwent a modified Fontan operation with the result of a severe stenosis at the medial and inferior right pulmonary artery. The branch ostium was affected in five cases, and in one 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 we used the internal jugular vein. We followed the technique reported by the Boston-Houston experience, with an extra stiff guide and Mullins sheath towards the site of the stenosis.

The procedure was effective in all cases except one. The mean pulmonary branch and balloon diameter was 11 +/- 3 mm and 14 +/- 2 mm, respectively, rate 1.2. The stenosis diameter rose from 4.8 +/- 1 to 11 +/- 2 mm (p < 0.001) with a percentage fall from 63 +/- 5 to 2 +/- 1% (p < 0.001). The pressure gradient fell from 30 +/- 5 to 5 +/- 1 mmHg (p < 0.001) and the right ventricle systolic pressure fell from 77 +/- 6 to 48 +/- 3 mmHg (p < 0.01). The mean followup was 10 +/- 3 months, a symptomatic and pulmonary perfusion improvement was seen. After 8 +/- 4 months, we evaluated six patients/nine stents with angiography, and we excluded thrombosis, aneurysms and occlusion of lobar or segmental branches. One case had a proximal stent re-stenosis as it did not cover the whole stenosis, so a new stent was implanted. Three patients/four stents underwent redilatation getting a slightly higher diameter than previously.

One patient had a stent migration and he underwent surgical stent retrieval.

Implantation of the Palmaz stent is a useful procedure for the treatment of native or post-operative pulmonary stenosis. It is possible to apply it to hypoplastic and ostial pulmonary stenosis. We confirm the effectiveness of redilatation at mid term.