OBJECTIVETo investigate the impact of the stents coated with sirolimus and anti-CD34 antibody on the short-term re-endothelialization and the long-term restenosis in Chinese Minipigs.

METHODSThree different types of stents [bare-metal stent (BMS), sirolimus-eluting stent (SES) and anti-CD34 antibody and sirolimus-coated stent (ASES)] were randomly implanted in the coronary arteries of 22 Chinese Minipigs. At two weeks after stenting, coronary angiography and optical coherence tomography (OCT) were performed in 10 experimental animals. At three months after stenting, coronary angiography and OCT were performed in the remaining 12 experimental animals. Histopathologic examination was performed on the coronary artery segments containing stent after the animals were executed.

RESULTS(1) No in-stent thrombosis and parietal thrombus were found by coronary angiography, OCT and histopathologic examination at two weeks post stenting. OCT analysis showed that the covered ratio of stent struts by neointima in ASES group was higher than in SES group [(55.56 ± 35.27)% vs. (41.82 ± 23.28)%, P < 0.05]. The mean thickness of neointima in ASES group was significantly higher than in SES group [(89.0 ± 5.0) µm vs. (32.0 ± 4.9) µm, P < 0.01] and BMS group [(89.0 ± 5.0) µm vs. (44.0 ± 7.2) µm, P < 0.01]. Histopathologic and scanning electron microscopy examinations demonstrated that the covering level and quality of stent struts by neointima in BMS and ASES group were both better than in SES group. (2) At three months follow-up, quantitative coronary angiography analysis found that late in-stent lumen loss in ASES group was significantly lower than in BMS group [(0.18 ± 0.06) mm vs.(0.35 ± 0.06) mm, P < 0.05]. OCT analysis showed that the percent neointimal hyperplasia in ASES and SES group was significantly lower than in BMS group [(34.75 ± 2.64)% and (35.63 ± 2.07)% vs. (48.28 ± 3.25)%, both P < 0.01]. Histopathologic analysis demonstrated that the percent areal restenosis of ASES and SES group were both significantly lower than that of BMS group [(28.65 ± 5.64)% and (29.33 ± 6.07)% vs. (46.18 ± 8.25)%, both P < 0.05].

CONCLUSIONThe stents coated with anti-CD34 antibody and sirolimus can attenuate the inhibitory effect of sirolimus on the re-endothelialization at two weeks after stenting and the anti-hyperplasia effect of sirolimus at three months after stenting.