Endovascular stents in the pulmonary circulation. Clinical impact on management and medium-term follow-up

The use of endovascular stents to relieve obstructions in the setting of non-balloon dilatable pulmonary artery stenosis has been encouraging. The benefits in management and the potential for restenosis, however, have not been defined. This study attempts to assess the impact of such implants on clinical outcomes and the pattern of stent incorporation within the vessel wall.

Fifty-five balloon-expandable stents were implanted in 42 patients 6.1 +/- 4.7 years of age. Patients were followed prospectively (median, 15 months) and recatheterized 1 year after implantation. Thirty-eight patients had the implants positioned percutaneously (49 implants), while 4 patients (6 implants) had intraoperative implantations. There was a diameter increase in the stenotic area of 109 +/- 79% (P < .0001) and a gradient reduction of 74 +/- 26% (P < .0001). Twelve stents straddled the orifice of side-branch pulmonary arteries and reduced flow to the branch vessel acutely in 7 patients. Twenty-nine patients underwent recatheterization, and various degrees and locations of acquired intraluminal narrowing were observed in all cases, particularly in areas of diameter mismatch between the stented and nonstented vessels. Eleven patients had further dilation with diameter improvement. Of the 38 patients who underwent percutaneous implantation, planned surgery for pulmonary artery stenosis was avoided in 33 and deferred in 4 patients. One patient who was considered inoperable had stent implantation as a palliative procedure. Symptomatic improvement was reported in 27 patients, and 15 patients remained asymptomatic.

Endovascular stents have a role in the treatment of pulmonary artery stenoses and positively affect clinical care. The stenosis relief, however, may be tempered by the development of intraluminal stent obstruction, which may require redilation (15 of 55 stents) and mandates long-term follow-up.