Objective
Patients with single-ventricle physiology pose a wide variety of therapeutic challenges. Pulmonary artery or anastomosis stenosis in single-ventricle physiology will have only subtle hemodynamic derangements due to the lack of the pumping chamber to force blood across the stenosis. This study aimed to evaluate the feasibility and usefulness of the stent implantation for treatment of branch pulmonary artery and anastomosis stenosis in children with univentricular hearts.
Methods
Retrospective analysis of 8 implanted stents between March 2014 and January 2015 in Shanghai Children's Medical Center. Transthoracic echocardiography, chest roentgenography and electrocardiography were carried out as follow-up studies at the second day after operation and 1, 3, 6, 12 months after the procedure.
Results
In all of eight patients( 6 males and 2 females), 5 cases were post-Glenn operation and 3 cases were post-Fontan operation. The median age was 6.6 years(range 4.0-8.5 years). The median weight was 19.5 kg(range 13.8-25.6 kg). 9 stents were implanted successfully in all patient, 6 in left pulmonary arteries, 2 in right pulmonary arteries and 1 in anastomosis. All stents were placed in the target lesion without any complication. The diameter of the narrowed segment improved from(3.63±2.06) mm to(7.89±1.62) mm(P<0.01). During follow-up no other complication occurred except thrombus in one patient because of discontinuation anticoagulation.
Conclusion
Branch pulmonary arterial stenosis in single-ventricle patients may often be underestimated due to the low pressure venous system and/or the development of venovenous collaterals bypassing and decompressing the pulmonary circuit. In these patients, even mild stenosis should be treated aggressively, especially in the presence of pleural effusions, pericardial effusions, protein-losing enteropathy and low-output states. Stent implantation is an effective method of treating branch pulmonary artery stenosis.
Key words:
Pulmonary artery; Stents; Child; Single ventricle
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.
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