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Relevant clinical history and physical exam
Case: A 84-year-old male.
At 2002, coronary artery bypass graft (CABG) using saphenous vein graft to distal left anterior descending artery (LAD) was performed at other institute, owing to the severe stenosis of proximal LAD.
At March 2013, Xience V stent was deployed to proximal right coronary artery (RCA) owing to de novo severe stenosis at mid bended lesion of #1.
Relevant test results prior to catheterization
At September 2015, angina pectoris was recurred.
At December 2015, coronary angiogram and PCI was conducted. There was a hazy de novo severe stenosis with thrombus and heavily calcification at mid RCA, with quantitative coronary analysis (QCA) data of percent diameter stenosis (%DS) of 76.5, and minimal lumen diameter (MLD) of 0.62 (Figure 1). The flow and stenosis of SVG, LMCA, and LCX were similar with those of March 2013.
Relevant catheterization findings
OFDI images after pre-dilation using 2-mm and 3-mm sized balloon showed the calcified nodule and combined red and white thrombus with minimal lumen area (MLA) of 2.41 mm 2 (Figure 1B). Ultimaster stent (3.5 x 38 mm) was placed with 16 atm, and concluded PCI owing to %DS of 22.7, and MLD of 2.92 by QCA (Figure 1C), and MLA of 6.98 mm2 and maximal incomplete stent apposition (ISA) distance of 110 μm by OFDI (Figure 1D).
In July 2016, he implicated in target lesion revascularization (TLR) following 2-month history of progressive exertional chest pain. Coronary angiogram showed thrombotic occlusion with TIMI-grade flow 2 (Figure 2A). Thus, this case was diagnosed as definite late stent thrombosis (LST) by ARC definition. Run through wire did not pass through the thrombotic lesion, and XTR wire passed the occluded lesion. Pre-dilation was done using 1-mm and 2-mm sized balloon. IVUS image showed the superficial high intensity layer with low-echo inside the stent approximately 20 mm proximal from the distal edge of Ultimaster stent (Figure 2C). Corresponding to the IVUS image, OCT image showed the superficial high intensity layer with low echo with MLA of 1.46 mm2 (Figure 2B ). Almost all of thrombus disappeared after ballooning using a 3.5 mm-size, and MLA was gained 3.46 mm2. Drug-eluting balloon was used with 16 atm. Superficial high intense layer was pressed insides tent as IVUS (Figure 2F) and OCT images (Figure 2E), and PCI was concluded with 25% stenosis on angiogram (Figure 2D). As QCA parameter, %DS was 22.7, and MLD was 2.92. OCT showed the MLA was 3.59 mm2, which was 49.6% of the primary PCI.
RESTART study reported that late stent thrombosis (LST) defined by ARC was caused by aggressive hyperplastic restenotic process.
The present study showed that calcified plaque co-existed with red and white thrombus in a case of definite LST.