Refinements in the implantation of pulmonary arterial stents: impact on morbidity and mortality of the procedure over the last two decades

Introduction: There is limited data on medium to long-term outcome, and the morbidity and mortality associated with the implantation, of pulmonary arterial stents. Purpose: To assess changes in morbidity and mortality over the last two decades. Methods: Retrospective analysis of all patients stented between September, 1989 and July, 2001. Results: We implanted 664 Palmaz stents in 338 patients. The overall number included 229 patients who had undergone repair of tetralogy of Fallot, in whom 468 stents were implanted, 61 patients with congenital stenosis of the branches of the pulmonary trunk, in whom we placed 115 stents, 16 patients after an arterial switch operation who had 38 stents, and 32 patients after the Fontan operation who had 43 stents implanted. The mean age was 12.2 years, and the mean weight was 38 kg. The mean systolic pressure gradient decreased from 41 to 8.7 mmHg, the mean diameter of the stented vessel increased from 5.4 to 11.2 mm, and the ratio of right ventricular to femoral arterial pressure decreased from 0.66 to 0.45, each of these being significant at the level of p being less than 0.01. At a mean follow-up of 5.6 years, the mean gradient was 20 mmHg, the mean ratio of pressure between right ventricle and femoral artery was 0.5, and mean luminal diameter was 9.3 mm. Complications included migration of the stent in 8 patients, and pulmonary edema, hemoptysis and death in 5 patients each. There has been no mortality or morbidity since July of 1997. Technical changes include conservative serial dilations in congenital pulmonary arterial stenosis, avoidance of over-dilation, and simultaneous implantation of stents in the right and left pulmonary arteries in those with systemic pulmonary arterial pressure. Technological advances included shorter stents, improved balloon, profiles, and central inflation of the stents. Conclusions: Modification of stenting practices, and increased experience of the operators over the last two decades, has virtually abolished any morbidity or mortality associated with the implantation of stents for congenital or postoperative pulmonary arterial stenoses.