Layered Neointimal Pattern Secondary to Intraluminal Clot Organization in an Optical Coherence Tomography Longitudinal Study

J INVASIVE CARDIOL 2018;30(10):E107-E108.

Key words: acute myocardial infarction, optical coherence tomography, restenosis, STEMI, stent thrombosis, thrombectomy

We present a case of follow-up optical coherence tomography (OCT) in a patient with non-obstructive intraluminal clot protrusion treated with medical therapy. The follow-up OCT scan showed layered neointimal changes similar to images observed in stent failure. 

A 37-year-old male presented with self-aborted anterior ST-elevation myocardial infarction. Urgent coronary angiogram showed thrombotic lesion in the proximal left anterior descending (LAD) artery (Figure 1). Multiple passes of aspiration thrombectomy retrieved a large amount of red thrombi. A drug-eluting stent was deployed in view of residual stenosis and clots (Figure 2, Video 1). Final OCT showed intraluminal clot protrusion at the proximal stented segment and proximal stent edge (Figure 3A, Video 2). The protruding clot was left for medical therapy with double antiplatelet agents because of the absence of flow limitation and edge dissection.

The patient remained clinically asymptomatic and scheduled follow-up coronary angiogram with OCT was performed 5 months after the index procedure. Follow-up OCT study showed the protruding clot had resolved with residual layered neointimal pattern at the proximal stent edge (Figure 3B, Video 3).

In a histopathological study on both patent and restenotic stents, 59% of the layered pattern after stenting has been shown to consist of collagen-rich or smooth muscle cell-rich tissue (eg, healed rupture or erosion) and 25% of layered pattern cases were a combination of neovascularization and smooth muscle cell rich neointimal tissue. Layered-type in-stent restenosis (ISR) was observed more frequently in stents implanted <1 year. Longitudinal follow-up of our case showed the layered neointimal pattern after resolution of intraluminal thrombus. The observed OCT neointimal change could be secondary to organized thrombi. This may explain the higher frequency of layered ISR pattern in cases of early stent failure, which could be secondary to clot organization after stent thrombosis.

See the accompanying video series here. 

From the Division of Cardiology, Department of Medicine and Therapeutics, Li Ka Shing Institute of Health and Science, Institute of Vascular Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript accepted April 19, 2018. 

Address for correspondence: Dr Chi Yuen Chan, Division of Cardiology, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, 9/F Clinical Science Building, Prince of Wales Hospital, 30-32 Ngan Shing Street, Shatin, NT, Hong Kong. Email: karlccy@gmail.com