TREATMENT OF PERIPHERAL PULMONARY STENOSES

Background. Peripheral pulmonary artery stenosis is a relatively frequ ent anomaly responsible for right ventricular hypertension, significan tly affecting the quality of life and the long-term prognosis of patie nts with congenital heart disease. Balloon angioplasty has been used t o relieve pulmonary artery; stenosis, but immediate and long-term resu lts have not been completely satisfactory. Conversely stent implantati on see,ns a promising and more effective technique for the treatment o f this vascular anomaly Methods: Between April 1987 and September 1997 indication for interventional cardiac catheterization has been establ ished far 150 patients. Balloon angioplasty was performed in 120 patie nts (162 procedures) and stent implantation in 60 patients (79 stents) . bl 30 patients, both procedures have been carried out, Indication I was based an the presence of right ventricular hypertension (right ven tricular/systemic peak systolic pressure ratio greater than or equal t o 0.5), right ventricular dysfunction, or a markedly unbalanced pulmon ary! blood flow, especially after bidirectional cavopulmonary anastomo sis. Criteria for technical success of balloon dilation were defined a s a greater than or equal to 50% increase in the predilation diameter, a greater than or equal to 50% decrease in the transstenotic pressure gr-adient, or a greater than or equal to 20% decrease in the right ve ntricular-to-aortic pressure ratio. Mean balloon/stenosis diameter rat io was 3.0 +/- 0.7 (range 1.8-4.2). Time between primary surgery/ballo on angioplasty and stent implantation was 18 +/- 7 months (range 8-21 months). Stainless steel balloon-expandable endovascular stents were m aximally dilated to 12-18 mm of diameter; and high-pressure dilations were performed to further expand the stent, if necessary. Results: Aft er 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 th e 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 re corded. Success rates using the above-mentioned criteria could be asse ssed as high as 60%. After stent implantation. the diameter of the ste notic 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/sys temic 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 st ent 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 t he balloon group patients, in respect to 2% of the stent group. Conclu sions: Peripheral pulmonary stenosis (PPS) is art important factor con ditioning outcome of patients with congenital heart defects. Balloon a ngioplasty may be technically effective , but it often fails if clinic al criteria and impact on patient's outcome are considered In our expe rience, the use of high-pressure balloons did not change the success r ate of balloon dilation. Stent implantation seems to offer a better an d more definitive approach for the relief of PPS.