Neoatherosclerosis and mural thrombus detection after sirolimus-eluting stent implantation

Although both optical coherence tomography (OCT) and angioscopy are robust tools for detecting intrastent thrombi and neoatherosclerosis in vivo, whether OCT findings are comparable with angioscopy findings remains unclear.

22 patients presenting with de novo lesions underwent 26 sirolimus-eluting stent (SES) implantations, with follow-up OCT and angioscopy at 10 months post-implantation for segmental assessment of the proximal, mid-, and distal SES segments (66 segments). The mean signal intensity index (signal intensity of the neointima/signal intensity of fibrous intimal hyperplasia) was quantified for angioscopically detected in-stent yellow and white segments. The detection rate for red thrombi was numerically higher with angioscopy than with OCT (17% vs. 9%; P=0.053). Angioscopically detected in-stent yellow segments were categorized into 3 OCT patterns: "high-attenuation tissue covering struts" (OCT-defined neoatherosclerosis), "high-attenuation tissue underneath struts," and "low-attenuation and low-intensity tissue covering struts"; further, macrophage-like appearance was most frequently observed with OCT-defined neoatherosclerosis (56%, 6.3%, and 0%, respectively, P<0.001). The mean signal intensity index of neoatherosclerosis was significantly lower than that of angioscopically detected in-stent white segments (0.929 vs. 0.997, P=0.004).

Current OCT-based definitions for thrombus detection may underestimate the presence of subclinical red thrombi. Qualitative and quantitative OCT assessments of the neointima may enhance the detection of neoatherosclerosis over SES in vivo.