Introduction

In-stent restenosis (ISR), although infrequent in the era of drug-eluting stents (DES), remains an Achilles’ heel of the percutaneous treatment of coronary artery lesions.

The new imaging modality optical coherence tomography (OCT) offers an interesting insight into the different patterns of this phenomenon.

As suggested by Gonzalo et al., the OCT appearance of restenotic tissue may be related to various factors such as clinical presentation, time from stent implantation, stent type, etc [1]. Still, the correlation between OCT appearance and the histopathological findings is not fully understood and warrants further investigation.

In the observation by Suzuki et al., the intravascular ultrasonography appearance of ISR components in native coronary arteries varied from echolucent to echodense images. Corresponding histology not only revealed smooth muscle cell proliferation, but also demonstrated delayed healing features such as organized fibrin deposition, macrophage and T-lymphocyte infiltration [2].

We present OCT images strongly suggesting different restenosis patterns among stent types, location of the lesion and various components within the same restenotic tissue resulting in distinct optical properties (figs 1-5).

Discussion

Neointimal stent strut coverage eliminates direct contact between pro-thrombotic stent material and the blood stream. Heterogeneous OCT appearance of neointimal tissue can be observed around struts in some DES, suggesting the presence of fibrin deposition and incomplete healing, possibly caused by the anti-proliferative drugs and polymer coating.

References

1. Gonzalo N, Serruys PW, Okamura T, et al. Optical coherence tomography patterns of stent restenosis. Am Heart J 2009; 158: 284-293.

2. Suzuki N, Angiolillo DJ, Monteiro C, et al. Variable histological and ultrasonic characteristics of restenosis after drug-eluting stents. Int J Cardiol 2008; 130: 444-448.