Assessment of potential relationship between wall shear stress and arterial wall response after bare metal stent and sirolimus-eluting stent implantation in patients with diabetes mellitus

BACKGROUND: Wall shear stress (WSS) has been associated with neointimal hyperplasia (NIH) following bare metal stent (BMS) implantation. Drug-eluting stents (DES) almost abolish NIH. Conversely, diabetes mellitus amplifies NIH response. The association between WSS and arterial wall response following DES and BMS implantation in diabetic patients remains to be evaluated. METHODS: The study involved 20 diabetic patients randomized to BMS (n = 9) or sirolimus-eluting stent (SES; n = 11) implantation in native coronary arteries. A computational fluid dynamic model applied 3D intravascular ultrasound (IVUS) and two-plane angiographic to measure WSS (Pa). IVUS assessments were performed post-procedure and at 9-months follow-up. The target segment encompassed the stent plus 5 mm distal and proximal edges. A total of 93 subsegments were evaluated: in-stent segments divided in three subsegments (proximal, mid and distal; n = 60) and proximal and distal edges (n = 33). RESULTS: Stent length was similar between BMS (17.4 +/- 7.3 mm) and SES (19.8 +/- 6.8 mm) groups. NIH was observed in all BMS subsegments (n = 27) versus one subsegment in the SES group (n = 33). WSS ranged from 0.52 to 4.20 Pa in the BMS and from 0.42 to 3.06 Pa in the SES group. There was no correlation between WSS and NIH in either stent group. In addition, there were no correlation between the change of external elastic membrane (EEM) or plaque growth at the edges and WSS. CONCLUSION: WSS was not associated with NIH after implantation of SES or BMS in diabetic patients. Plaque growth or the change of EEM at the edges were not associated with WSS either.