Stent implantation into ductus arteriosus: a new alternative of palliative treatment of duct-dependent pulmonary circulation

Background The technical aspects of ductal stenting have been reported, but little is known about the fate of the duct after stent implantation. Objectives To determine the effects of PDA stenting on the degree of cyanosis, blood oxygen saturation, long-term patency of PDA, and the growth of pulmonary artery and its branches, in patients with duct-dependent pulmonary circulation. Methods This was a case series study conducted at the Depart- ment of Pediatric Cardiology, Institut Jantung Negara (National Heart Institute), Kuala Lumpur, Malaysia from November 1996 to Septem- ber 2001 on patients with duct-dependent pulmonary circulation who underwent stent implantation. All patients were followed-up until oc- clusion or block occurred or until the end of follow-up time. The evalu- ation consisted of clinical manifestations, electrocardiography, chest x-ray, echocardiography, and cardiac catheterization. Results Stent was successfully implanted in 60 patients (84%), failed in 7 patients (10%) and contra indicated in 4 patients (6%). There was significant improvement on the degree of cyanosis after stent implantation (p<0.0001). The blood oxygen saturation signifi- cantly increased from 74% (ranged 42-93; SD 12) before proce- dure, to 90% (ranged 62-100; SD 8) afterward (p<0.0001). The mean duration of follow-up time was 14.2 months (ranged 2.5-50.8; SD 13) and the minimal patency of PDA was 11.2 months (ranged 1.1- 47.7; SD 10.7) after implantation. At the end of follow-up, the stents were widely patent in 33 patients (55%), stenotic in 15 patients (25%) and spontaneously occluded in 12 patients (20%). There was in- creased growth of pulmonary artery as measured by McGoon ratio from 1.23 (ranged 0.4-2.3; SD 0.4) to 1.81 (ranged 0.7-0.9; SD 0.57), and no distortion of pulmonary artery and its branches found. Conclusion Stent implantation into ductus arteriosus decreased the degree of cyanosis, increased blood oxygen saturation, main- tained long-term patency of ductus arteriosus, and promoted the increased growth of pulmonary artery without distortion of pulmo- nary artery and its branches