OBJECTIVETo study the relationship between inflammation and neointimal proliferation after coronary stent implantation in porcine model.

METHODSTwenty normal minipigs were randomly divided into group A (implanted with 316L bare metal stents), group B (implanted with 605L bare metal stents), group C (implanted with PLGA coating 605L stents), and group D (implanted with rapamycin-loaded PLGA coating 605L stents). Each minipig was implanted with two same stents in left anterior descending artery and right coronary artery. Four weeks later, the animals were sacrificed and histomorphometric measurements on the stent-segment coronary arteries were made to calculate the correlation between inflammation area and neointimal area.

RESULTSGroup D had the smallest neointimal area [(0.64 +/- 0.38) mm2, P < 0. 001] and inflammation area (median 0.00 mm2, P = 0.009) among all the groups, while there were no statistical differences among group A, B, and C in neointimal area [(2.09 +/- 0.90), (2.11 +/- 1.07), and (1.42 +/- 0.35) mm2 respectively] and in inflammation area (0.22 , 0.21, and 0.09 mm2, respectively). Bivariate correlation analysis showed that the inflammation area was positively correlated with the neointimal area (P < 0.001, correlation coefficient = 0.719). When stent type, mean injury score, and EEL area were adjusted, partial correlations analysis showed that the inflammation area was still positively correlated with the neointimal area (P = 0.01, correlation coefficient = 0.498).

CONCLUSIONInflammation promotes the neointimal proliferation after coronary stent implantation. Sirolimus-eluting stent may reduce the inflammatory response.