Healing Rates and Coverage Differ Between Stents

Faster neointimal coverage and thrombi resolution with bare-metal stents

FRIDAY, Sept. 8 (HealthDay News) -- Sirolimus-eluting stents have delayed neointimal coverage and slower resolution of thrombi compared with bare-metal stents six months after implantation, according to research published in the September issue of the European Heart Journal.

Masamichi Takano, M.D., of the Nippon Medical School in Chiba, Japan, and colleagues evaluated 46 patients (36 with stable angina and 10 with acute coronary syndrome) who were treated with 33 sirolimus-eluting stents (SES) and 33 bare-metal stents (BMS). Immediately after the procedure and six months after stenting, the stented segments, edges and overlapping segments were studied by angioscopy. Neointimal coverage was graded as none through invisible struts. The presence or absence of thrombi was also evaluated.

The mean neointimal coverage grade was lower in the SES group than in the BMS group. Twenty-seven segments (41 percent of all segments; six edges, 15 bodies, and six overlapping segments) of the SES group and four segments (6 percent of all segments; four bodies) of the BMS group had no neointimal coverage. The frequency of persistence of thrombus was significantly higher in the SESs (86 percent) than in the BMSs (29 percent).

"Our angioscopic study suggested both a delayed neointimal proliferation and a slow process in thrombus disappearance in the SES in comparison with those in the BMS at 6 months after their implantation," the authors write. "Further long-term follow-up studies to clarify the serial changes of the neointima and thrombi inside the SES are thus called for."

In an accompanying editorial, Walter Desmet, M.D., from the University Hospital Gasthuisberg in Leuven, Belgium, suggests that the SES be reserved "for the patients for whom the greatest benefit can be expected."

The study was partially funded by the Eisai Corporation.

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