Treatment of Peripheral Pulmonary Stenoses
Authors: FORMIGARI ROBERTO , CASADO JORGE , SANTORO GIUSEPPE , BALLERINI LUIGI 
Published: June 2007

Background: Peripheral pulmonary artery stenosis is a relatively frequent anomaly responsible for right ventricular hypertension, significantly affecting the quality of life and the long‐term prognosis of patients with congenital heart disease. Balloon angioplasty has been used to relieve pulmonary artery stenosis, but immediate and long‐term results have not been completely satisfactory. Conversely, stent implantation seems a promising and more effective technique for the treatment of this vascular anomaly. Methods: Between April 1987 and September 1997, indication for interventional cardiac catheterization has been estabilished for 150 patients. Balloon angioplasty was performed in 120 patients (162 procedures) and stent implantation in 60 patients (79 stents). In 30 patients, both procedures have been carried out. Indication was based on the presence of right ventricular hypertension (right ventricular/systemic peak systolic pressure ratio ≥ 0.5), right ventricular dysfunction, or a markedly unbalanced pulmonary blood flow, especially after bidirectional cavopulmonary anastomosis. Criteria for technical success of balloon dilation were defined as a ≥ 50% increase in the predilation diameter, a ≥ 50% decrease in the transstenotic pressure gradient, or a ≥ 20% decrease in the right ventricular‐to‐aortic pressure ratio. Mean balloon/stenosis diameter ratio was 3.0 ± 0.7 (range 1.8–4.2). Time between primary surgery/balloon angioplasty and stent implantation was 18 ± 7 months (range 8–21 months). Stainless steel balloon‐expandable endovascular stents were maximally dilated to 12–18 mm of diameter, and high‐pressure dilations were performed to further expand the stent, if necessary. Results: After balloon angioplasty, the diameter of the stenotic segment increased from 3.1 ± 0.3 to 5.1 ± 1.4 mm (P < 0.01), the gradient across the stenotic segment dropped from 51 ± 19 to 28 ± 8 mmHg (P < 0.01), and the right ventricular/systemic peak pressure ratio decreased from 0.81 ± 0.20 to 0.65 ± 0.15 (P < 0.05). No significant difference between procedures with low‐pressure and high‐pressure dilation was recorded. Success rates using the above‐mentioned criteria could be assessed as high as 60%. After stent implantation, the diameter of the stenotic segments increased from 3.5 ± 1.2 to 13.2 ± 3.4 mm (P < 0.01), the pressure gradient across the stenotic segment dropped from 53 ± 30 to 13 ± 10 mmHg (P < 0.01), and the mean right ventricular/systemic pressure ratio decreased from 0.84 ± 0.2 to 0.40 ± 0.15 (P < 0.01). Immediate overall success for balloon angioplasty was achieved in 73 of 120 patients compared with 58 of 60 patients submitted to stent implantation (60% vs 97%, P < 0.001). The complication rate was 6.9% (5/162 procedures) in the balloon angioplasty group and 1.2% (1/79 implants) in the stent group. Restenosis has been recorded in 25% of the balloon group patients, in respect to 2% of the stent group. Conclusions: Peripheral pulmonary stenosis (PPS) is an important factor conditioning outcome of patients with congenital heart defects. Balloon angioplasty may be technically effective, but it often fails if clinical criteria and impact on patient's outcome are considered. In our experience, the use of high‐pressure balloons did not change the success rate of balloon dilation. Stent implantation seems to offer a better and more definitive approach for the relief of PPS.