Impact of calcified lesion on the intimal hyperplasia after implantation of drug eluting stent: an intravascular ultrasound study

Abstract

To investigate the impact of calcified lesion on the intimal hyperplasia after implantation of drug eluting stent. Ninety-nine rapamycin-eluting stents were implanted into the left anterior descending branches of coronary artery of 97 patients with 99 lesions. Eight months later intravascular ultrasound (IVUS) was used to examine the cross section area (CSA) of the external elastic membrane (EEM) at the stent inlet and at the stent outlet, in-stent CSA, CSA of the lumen, area of neo-intima (in-stent area minus lumen CSA), the maximum and minimum diameters of stent, and symmetry index of stent (minimal diameter of stent/maximum diameter of stent). Forty-one lesions were calcified and 58 non-calcified. Fourteen of the 99 lesions in the 97 patients developed intimal hyperplasia. The inlet stent CSA of the calcified group was (7.30 +/- 1.94) mm(2), similar to that of the non-calcified group (6.58 +/- 1.96) mm(2); the outlet CSA of the calcified group was (6.74 +/- 2.02) mm(2), similar to that of the non-calcified group (6.14 +/- 1.82) mm(2). The minimum stent CSA of the calcified group was (4.97 +/- 1.51) mm(2), significantly smaller than that of the non-calcified group (6.10 +/- 1.87) mm(2) (P < 0.05), the symmetry index of the calcified group was 0.92 +/- 0.07, significantly lower than that of the non-calcified group (0.92 +/- 0.07, P < 0.05), and the intimal area of the calcified group was (0.02 +/- 0.20) mm(2), significantly smaller than that of the non-calcified group (0.53 +/- 1.50) mm(2) (P < 0.05). Drug eluting stent implantation in the patients with calcified lesions has a less stent CSA and poor symmetry, and less intimal hyperplasia compared with those in the non-calcified lesions.