Initial experience with the new Pul-Stent in treating postoperative branch pulmonary artery stenosis

Abstract

The Pul-stent is a new cobalt alloys stent, specially licensed for pulmonary artery stenosis. The aim of this study was to investigate the value of the stent implantation as the treatment of postoperative pulmonary artery stenosis. Clinical practice was carried out to evaluate effectiveness, safety and maneuverability of Pul-stent in the defined clinical setting. Transthoracic echocardiography, chest roentgenography and electrocardiography were carried out as follow-up studies at 1 and 3 months after procedures. Ten patients (7 males and 3 females) received Pul-stent implantation in left or right pulmonary arteries (9 stents in left and 1 stent in right). For 9 cases transcatheter stent implantation was performed and in I case hybrid procedure. The median age was 7. 9 years (range 3. 4 - 13. 7 years). The median weight was 22. 3 kg (range 13 - 32 kg). Among them 6 cases were post surgical repair of tetralogy of Fallot, 2 cases were after Fontan procedures, 1 patient was post surgical repair of pulmonary atresia with ventricular septal defect, and 1 patient had stenosis at Glenn pathway. The pressure gradient at the stenosis decreased from (31. 6 ± 10. 2) mmHg(1 mmHg =0. 133 kPa) to (7. 3 ± 10. 3) mmHg, and the diameter of the narrowest segment increased from (4. 0 ± 2. 3) mm to (9. 6 ± 2. 7) mm, the right ventricle to aortic pressure ratio decreased from 0. 54 to 0. 36, all of these improvements were statistically significant (t = 3. 9, -9. 7, 4. 5; P =0. 008, 0. 000, 0. 004). The total procedure time ranged from 55 to 220 min (median 117 min) , and the fluoroscopy time ranged from 9 to 67 min (median 26 min). There were 2 cases of post-stenting pneumorrhagia. No stent fracture, stent malposition and other severe complications were observed. Initial follow-up of 1 and 3-months showed good results with maintenance of improved caliber of the stented vessel, and the gradient across the stenosis area measured by echocardiography was (32. 0 ± 14. 6) mmHg after 3 months. Compared with before stentifng ((40.6 ± 15. 2) mmHg) and 1 month later ((30. 6 ± 13. 6) mmHg), the difference was not statistically significant (t =2. 2,1. 76; P =0. 07, 0. 10). Pul-Stent tracking and delivery was excellent, the initial experience has shown that Pul-stent implantation was effective and safe in treating post-operative branch pulmonary artery stenosis. Further follow-up study should be conducted to make sure whether those good results would be kept constant.