Intravascular ultrasound analysis of small vessel lesions treated with the Sparrow coronary stent system: results of the CARE II trial.

OBJECTIVES: The aim of this study was to evaluate the Sparrow sirolimus-eluting stent (Sparrow-SES) against the Sparrow bare-metal stent (Sparrow-BMS) and conventional balloon-expandable bare-metal stent (BMS: Driver/Micro-Driver stent, Medtronic Vascular, Santa Rosa, CA). BACKGROUND: The Sparrow stent (Biosensors International, Singapore) consists of a guide wire-based, self-expandable, ultra-thin nitinol stent. The performance of this device with sirolimus in a fully biodegradable polymer has not been determined. METHODS: A total of 74 patients were included in this intravascular ultrasound (IVUS) sub-study of the CARE II trial, which was a prospective, randomized, multicenter trial in the treatment of single de novo native coronary artery lesions in vessels ranging from 2.0 mm to 2.75 mm in diameter (Sparrow-SES: n = 31, Sparrow-BMS: n = 22, BMS: n = 21). RESULTS: Stent volume index (VI) was significantly increased 8-month later in Sparrow-SES and Sparrow-BMS, but not in BMS (4.0 ± 1.0 to 4.6 ± 1.0 mm(3) /mm, p<0.0001, 4.0 ± 0.6 to 4.4 ± 0.8 mm(3) /mm, p<0.05, and 5.2 ± 1.0 to 5.1 ± 0.9 mm(3) /mm, p=0.421, respectively). % neointimal obstruction in Sparrow-SES was significantly smaller than those in Sparrow-BMS and BMS at follow-up (17.6 ± 9.4 vs. 36.2 ± 13.8 and 39.9 ± 11.1%, p<0.001). Sparrow-SES showed a mean 15% stent expansion and good suppression of neointimal proliferation, resulting in a significantly lower percentage of change in lumen VI during follow-up period (Sparrow-SES: -6.2 ± 16.2%, Sparrow-BMS: -30.4 ± 11.6%, BMS: -40.4 ± 10.0%, p<0.001). CONCLUSIONS: The self-expanding Sparrow-SES demonstrated chronic stent expansion, good suppression of neointimal proliferation and resulted in a more preserved lumen in stented small vessels compared with the Sparrow-BMS and conventional balloon expandable BMS.

Intravascular ultrasound comparison of small coronary lesions between novel guidewire-based sirolimus-eluting stents and conventional sirolimus-eluting stents.

BACKGROUND: The Sparrow stent system (Biosensors International) consists of a self-expanding, ultra-thin nitinol stent mounted within a 0.014″ guidewire designed for small or tortuous coronary lesions. We compared the intravascular ultrasound (IVUS) findings between the novel self-expanding sirolimus-eluting stent (Sparrow-SES) and a conventional balloon-expandable sirolimus-eluting stent (Cypher-SES) in patients with small coronary disease. METHODS: We examined 14 lesions treated with the Sparrow-SES from CARE II, compared with 22 small vessel lesions treated with Cypher-SES. IVUS examination was performed post-procedure and 8 months later. Volumetric data were standardized by length as volume index (VI; mm³/mm). RESULTS: While baseline stent VI trended smaller in Sparrow-SES, follow-up stent VI became similar between the 2 groups due to a significant increase of stent VI in self-expanding Sparrow-SES during the follow-up period. At 8 months, Sparrow-SES showed greater neointima than Cypher-SES (0.8 ± 0.6 mm³/mm vs 0.2 ± 0.2 mm³/mm; P<.001). However, the decrease in lumen VI was only 0.3 ± 0.7 mm³/mm in Sparrow-SES, as compared to 0.1 ± 0.3 mm³/mm in Cypher-SES (P=.259), since the late loss due to neointimal hyperplasia was partly counterbalanced by the chronic stent expansion in Sparrow-SES. CONCLUSION: While 8-month follow-up of Sparrow-SES revealed greater amounts of neointimal hyperplasia compared with conventional Cypher-SES, chronic stent expansion preserved the lumen by increasing stent volume. This novel, guidewire-based, self-expanding stent system designed to be delivered through complex anatomies may be useful to treat patients with small-caliber coronary lesions by offering sufficient lumen preservation at follow-up.

Intravascular ultrasound comparison of small coronary lesions between novel guidewire-based sirolimus-eluting stents and conventional sirolimus-eluting stents

The Sparrow stent system (Biosensors International) consists of a self-expanding, ultra-thin nitinol stent mounted within a 0.014½ guidewire designed for small or tortuous coronary lesions. We compared the intravascular ultrasound (IVUS) findings between the novel self-expanding sirolimus-eluting stent (Sparrow-SES) and a conventional balloon-expandable sirolimus-eluting stent (Cypher-SES) in patients with small coronary disease. Methods. We examined 14 lesions treated with the Sparrow-SES from CARE II, compared with 22 small vessel lesions treated with Cypher-SES. IVUS examination was performed post-procedure and 8 months later. Volumetric data were standardized by length as volume index (VI; mm3/mm). Results. While baseline stent VI trended smaller in Sparrow-SES, follow-up stent VI became similar between the 2 groups due to a significant increase of stent VI in self-expanding Sparrow-SES during the follow-up period. At 8 months, Sparrow-SES showed greater neointima than Cypher-SES (0.8 ± 0.6 mm3/mm vs 0.2 ± 0.2 mm3/mm; P<.001). However, the decrease in lumen VI was only 0.3 ± 0.7 mm3/mm in Sparrow-SES, as compared to 0.1 ± 0.3 mm3/mm in Cypher-SES (P=.259), since the late loss due to neointimal hyperplasia was partly counterbalanced by the chronic stent expansion in Sparrow-SES. Conclusion. While 8-month follow-up of Sparrow-SES revealed greater amounts of neointimal hyperplasia compared with conventional Cypher-SES, chronic stent expansion preserved the lumen by increasing stent volume. This novel, guidewire-based, self-expanding stent system designed to be delivered through complex anatomies may be useful to treat patients with small-caliber coronary lesions by offering sufficient lumen preservation at follow-up.