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Intravascular Sonotherapy Decreases Neointimal Hyperplasia After Stent Implantation in Swine

2001; Lippincott Williams & Wilkins; Volume: 103; Issue: 14 Linguagem: Inglês

10.1161/01.cir.103.14.1828

1524-4539

Peter J. Fitzgerald, Atsushi Takagi, Michelle Moore, Motoya Hayase, Frank D. Kolodgie, D. Corl, Menahem Nassí, Renu Virmani, Paul G. Yock,

Ultrasound and Cavitation Phenomena

Background —Intimal hyperplasia and subsequent in-stent restenosis remain a major limitation after stent implantation. In vitro cell culture studies show that low-frequency, noncavitational ultrasound energy may impact smooth muscle cell proliferation. Accordingly, we assessed the efficacy of intravascular sonotherapy treatment on intimal hyperplasia in a swine stent model. Methods and Results —After balloon injury, biliary stents (Johnson & Johnson) were implanted in the femoral arteries of 14 swine. A total of 48 stented sites were randomized to sonotherapy or sham treatment using a custom-built, 8-French catheter intravascular sonotherapy system ( URX , PharmaSonics Inc). After stent deployment, ultrasound energy (700 KHz) was applied to the treatment group for up to 5 minutes. Smooth muscle cell proliferation was assessed using bromodeoxyuridine histology preparation (BrdU) at 7 days in 28 stented sites. At 28 days, the neointimal thickness and the ratio of neointimal/stent area (percent stenosis) was calculated by histomorphometric quantification in 20 stented sites. At 7 days, percent of BrdU staining was significantly reduced in the sonotherapy group compared with the sham group (24.1±7.0% versus 31.2±3.0%, P <0.05). At 28 days, percent stenosis was significantly less in the sonotherapy group than in the sham group (36±24% versus 44±27%, P <0.05), and the mean neointimal thickness in the sonotherapy group was less than in the sham group (417±461 μm versus 643±869 μm, P =0.06). Conclusions —In this swine peripheral model, intravascular sonotherapy seemed to decelerate cellular proliferation and decrease in-stent hyperplasia. Therefore, intravascular sonotherapy may be an effective form of nonionizing energy to reduce in-stent restenosis.