Atherosclerotic plaque behind the stent changes after bare-metal and drug-eluting stent implantation in humans: Implications for late stent failure?

BACKGROUND AND AIMS: The natural history and the role of atherosclerotic plaque located behind the stent (PBS) are still poorly understood. We evaluated the serial changes in PBS following bare-metal (BMS) compared to first-generation drug-eluting stent (DES) implantation and the impact of these changes on in-stent neointimal hyperplasia (NIH).

METHODS: Three-dimensional coronary reconstruction by angiography and intravascular ultrasound was performed after intervention and at 6-10-month follow-up in 157 patients with 188 lesions treated with BMS (n = 89) and DES (n = 99).

RESULTS: There was a significant decrease in PBS area (-7.2%; p < 0.001) and vessel area (-1.7%; p < 0.001) after BMS and a respective increase in both areas after DES implantation (6.1%; p < 0.001 and 4.1%; p < 0.001, respectively). The decrease in PBS area significantly predicted neointimal area at follow-up after BMS (β: 0.15; 95% confidence interval [CI]: 0.10-0.20, p < 0.001) and DES (β: 0.09; 95% CI: 0.07-0.11; p < 0.001) implantation. The decrease in PBS area was the most powerful predictor of significant NIH after BMS implantation (odds ratio: 1.13; 95% CI: 1.02-1.26; p = 0.02).

CONCLUSIONS: The decrease in PBS area after stent implantation is significantly associated with the magnitude of NIH development at follow-up. This finding raises the possibility of a communication between the lesion within the stent and the underlying native atherosclerotic plaque, and may have important implications regarding the pathobiology of in-stent restenosis and late/very late stent thrombosis.