Ultra-High-Pressure Balloon Angioplasty for Treatment of Resistant Stenoses Within or Adjacent to Previously Implanted Pulmonary Arterial Stents Brief title: Ultra-high pressure redilation of PA stents

Background. Stents are essential tools in the management of pulmonary arterial (PA) stenosis in patients with congenital heart disease. Although stents can usually be reexpanded as children grow, resistant instent or peri-stent obstruction can complicate the management of PA stents. Angioplasty with ultra-highpressure (UHP) balloons may facilitate successful treatment of stent-associated PA stenoses that are resistant to high-pressure dilation. Methods and Results. We reviewed patients who underwent UHP angioplasty of in-stent or peri-stent PA stenoses that were resistant to high-pressure redilation. A resistant stenosis was defined as a residual balloon waist during high-pressure redilation of the stent, along with a pressure gradient and/or angiographic stenosis. Thirty-four lesions in 29 patients, including 8 with multiple concentric, overlapping, or adjacent stents, were included. The median age at UHP angioplasty was 9 years, and a median of 4 years had elapsed since unsuccessful high-pressure angioplasty. Thirty-one of the 34 (91% [81-100%]) UHP angioplasty procedures were successful in relieving the resistant stenosis. Balloon:waist diameter ratios were conservative (median 1.26), reflecting the ability of UHP balloons to “fracture” nearly all obstructions. After UHP dilation, lesion diameter increased by a median of 3.1mm (36%), significantly more than after prior high-pressure dilation (1.3mm, 19%; p<0.001). In 5 lesions, UHP angioplasty fractured the stent, allowing further vessel expansion. There were no vascular or other complications. Conclusions. UHP angioplasty was safe and effective for treatment of stent-related resistant PA stenosis in this series; the ability to fracture maximally expanded stents may extend the utility of stents in the pediatric population. Abstract word count: 249word count: 249