Impact of small thrombus formation in restenotic bare-metal stent lesions associated with acute coronary syndrome: Identification by optical coherence tomography

Coronary spasm (CS) plays an important role in the pathogenesis of many kinds of ischemic heart disease. However, morphological characteristics of coronary artery of CS remain unknown. We evaluated 37 patients with coronary spastic angina (CSA) who underwent diagnostic acetylcholine (ACh) provocation test, and 2 acute coronary syndrome patients suspected to have severe CS. The intravascular optical coherence tomography (OCT) was performed after complete dilatation of coronary artery in all patients and additionally performed during ACh-induced CS in 4 patients. Based on the ACh provocation test, 23 patients who developed CS and ischemic ECG changes were diagnosed as coronary spastic angina (CSA), and other 14 patients without CS were referred as CS-negative patients. CS-negative patients were further divided into 2 sub-groups according to the lipid and/or calcification content in coronary arterial wall by OCT findings. Intravascular OCT revealed most coronary segments with ACh-induced CS had homogenous intima thickening, and quantitative OCT analysis showed that CS-positive segments had significantly larger intima area compared with CS-negative segments without lipid and/or calcification (2.73±0.07 vs. 1.36±0.06 mm 2 , P<0.001). By contrast, CS-positive segments had significantly smaller intima area compared with CS-negative segments with lipid and/or calcification (2.73±0.07 vs. 4.51±0.17 mm 2 , P<0.001). During ACh-induced CS, lumen and total vascular area significantly decreased, whereas intima area did not change in comparison with complete vasodilatation. Furthermore, luminal surface of intimal layer formed markedly wavy configuration during CS. In CSA cases with acute coronary syndrome, we observed additional findings of intima injury as erosion and thrombus formation at spasm site. Coronary spasm occurs in coronary artery with diffuse intima thickening without lipid and/or calcification content but not in artery either without intima thickening or with lipid and/or calcification, and coronary spasm sometimes induces intimal injury by itself which may cause acute coronary event.

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Abstract 3322: Chronic Vascular Responses To Sirolimus-eluting Stent Compared With Bare-metal Stent In Diabetic Patients: Evaluated By Optical Coherence Tomography.

Circulation ◽

10.1161/circ.116.suppl_16.ii_748-c ◽

2007 ◽

Vol 116 (suppl_16) ◽

Author(s):

Takashi Kubo ◽

Toshio Imanishi ◽

Hiroki Matsumoto ◽

Manabu Kashiwagi ◽

Hiroto Tsujioka ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Neointimal Hyperplasia ◽

Bare Metal Stent ◽

Diabetic Patients ◽

Imaging Method ◽

Bare Metal ◽

Optical Coherence ◽

Metal Stent ◽

Cross Sectional ◽

Sirolimus Eluting Stent

OBJECTIVE: An optical coherence tomography (OCT) study was performed to compre the vascular response to sirolimus-eluting stent (SES) with bare-metal stent (BMS) in patients with diabetic mellitus (DM). BACKGROUND: Despite advances in the medical treatment and revascularization procedures, coronary artery disease remains a leading cause of morbidity and mortality in patients with DM. Few retrospective subgroup analyses of pivotal clinical trials have suggested that SES may be effective for reduction of restenosis in diabetic patients. OCT is a new intravascular imaging method with a high resolution of approximately 10 micrometer and allows us to evaluate instent neointimal hyperplasia (NIH) in vivo. METHODS and RESULTS: Serial OCT analyses were performed in 60 lesions (SES in DM patients=19; SES in non-DM patients=14; BMS in DM patients=10; BMS in non-DM patients=17) at 9-month follow-up. A total of 6920 stent struts were visualized by OCT and NIH thickness inside each strut and incidence of exposed stnet struts were evaluated in cross-sectional image. The NIH thickness was significantly different among 4 groups (97 +/− 100 vs. 43 +/− 61 vs. 425 +/− 206 vs. 209 +/− 138 micrometer, respectively). The NIH thickness of SES in DM was significantly thicker than that of SES in non-DM (p<0.001), although it was significantly thinner than that of BMS in DM (p<0.001) or BMS in non-DM (p<0.001). All struts of BMS were covered by neointima, but 14% of struts of SES were exposed. The incidence of exposed struts and exposed struts with inadequate apposition in DES were significantly lower in DM compared with those in non-DM (5% vs. 34%, p<0.0001; 2% vs. 5%, p <0.001, respectively). Moreover, the frequency of DES with partially exposed strut was significantly lower in DM than non-DM (32% vs. 71%, p<0.027). CONCLUSION: The present OCT study revealed that DES inhibited the NIH effectively with low incidence of exposed stent strut in DM patients at 9-month after implantation.

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