Is visceral fat really a coronary risk factor? A multi-detector computed tomography study.

Metabolic syndrome (MS) is currently considered to be a risk factor for arteriosclerotic disease. The accumulation of visceral fat leads to arteriosclerotic disease after other risk factors have developed and either direct or mutual effects occur. The aim of this study was to verify whether visceral fat serves as an independent coronary risk factor. A total of 3157 patients who had undergone multi-detector computed tomography (MDCT) were analyzed via computed tomographic angiography and the measurement of their visceral fat area. Coronary arteries with > 70% stenosis were considered to be significant. The visceral fat area was measured at the umbilical level, and an area of 100 cm2 or more was defined as visceral obesity. Coronary risk factors (ie, hypertension, dyslipidemia, diabetes mellitus, family history, and smoking) were obtained from the patient medical records. The patients were divided into two groups: a visceral obesity group, 1130 patients (137.0 ± 31.1 cm2) and a nonvisceral obesity group, 2027 patients (57.3 ± 25.8 cm2). A significant difference in the incidence of coronary stenosis between the two groups was observed. According to multivariable analysis, the factors affecting coronary stenosis were age, gender, dyslipidemia, diabetes mellitus, and the ratio of visceral to subcutaneous fat. Visceral obesity was not found to be an independent coronary risk factor. Visceral obesity demonstrated the predominant presence of coronary risk factors.

Clinical significance of low signal intensity area surrounding stent struts identified by optical coherence tomography.

Previous intravascular ultrasound studies have shown that echolucent neointimal hyperplasia occasionally appears after bare-metal stent (BMS) or sirolimus-eluting stent (SES) implantation. Optical coherence tomography (OCT) studies have also demonstrated that paclitaxel-eluting stent (PES) restenosis exhibited similar images showing low signal intensity areas (LSIA) surrounding stent struts and three-layer appearance (TLA). The aim of the present study was to investigate the clinical significance of LSIA on OCT images in various types of stents. Fifty nine consecutive patients who underwent scheduled follow-up coronary angiography and OCT were enrolled. There was no significant difference in the prevalence of LSIA among the 3 stent groups (BMS 30%, SES 19%, PES 28%, P = 0.70). LSIA thickness was larger in the PES group than in the other stent groups (BMS 0.51 ± 0.21 mm, SES 0.35 ± 0.06 mm, PES 0.87 ± 0.19 mm, P < 0.01). The ratio of LSIA thickness to the neointimal thickness was also larger in PES compared with other stents (BMS 53 ± 9 %, SES 57 ± 8 %, PES 77 ± 5 %, P < 0.01). Also, LSIA thickness in patients with in-stent restenosis (ISR) was significantly larger than in those without ISR (0.37 ± 0.37 mm versus 0.12 ± 0.26 mm, P = 0.048). Our results suggest that LSIA might be involved in excessive neointimal formation, and that the healing response after PES implantation might be different from BMS or SES.

Effect of strut thickness on neointimal atherosclerotic change over an extended follow-up period (≥ 4 years) after bare-metal stent implantation: intracoronary optical coherence tomography examination.

BACKGROUND: Neointima inside the bare-metal stents (BMSs) can transform into atherosclerotic tissue during an extended follow-up because of a persistent inflammatory reaction to the metal. We sought to investigate whether strut thickness may impact on the atherosclerotic change in neointima 4 years or more after BMS implantation using optical coherence tomography. METHODS: Forty-six stented lesions of 41 patients with BMS ≥ 4 years after implantation who underwent optical coherence tomography were enrolled in the study. The strut was defined as thin when less than 100 µm and thick when ≥ 100 µm. According to these criteria, stents were divided into 2 groups (thin strut n = 19, thick strut n = 27). Neointimal tissue was categorized into normal neointima, characterized by a signal-rich band without signal attenuation, or lipid-laden intima, with marked signal attenuation and a diffuse border. Intimal disruption, thrombus, and neovascularization were also evaluated. RESULTS: The mean period after implantation was 98.2 ± 25.8 months in the thin-strut group and 91.1 ± 22.8 months in the thick-strut group (P = .330). Lipid-laden intima (70% vs 32%, P = .016), thin-cap fibroatheroma-like intima (59% vs 16%, P = .0056), and intimal disruption (48% vs 16%, P = .031) were observed more frequently in the thick-strut group than in the thin-strut group, but no significant difference was observed in the frequency of thrombus. Although peristrut neovascularization was a common finding in both groups (thick vs thin 81% vs 79%, P = 1.000), the frequency of intraintima neovascularization tended to be higher in the thick-strut group (67% vs 42%, P = .135). CONCLUSIONS: A thinner strut thickness may have favorable effects on neointimal atherosclerotic changes after BMS implantation.

Comparison of contrast media and low-molecular-weight dextran for frequency-domain optical coherence tomography.

BACKGROUND: Although an intracoronary frequency-domain optical coherence tomography (FD-OCT) system overcomes several limitations of the time-domain OCT (TD-OCT) system, the former requires injection of contrast media for image acquisition. The increased total amount of contrast media for FD-OCT image acquisition may lead to the impairment of renal function. The safety and usefulness of the non-occlusion method with low-molecular-weight dextran L (LMD-L) via a guiding catheter for TD-OCT image acquisition have been reported previously. The aim of the present study was to compare the image quality and quantitative measurements between contrast media and LMD-L for FD-OCT image acquisition in coronary stented lesions. METHODS AND RESULTS: Twenty-two patients with 25 coronary stented lesions were enrolled in this study. FD-OCT was performed with the continuous-flushing method via a guiding catheter. Both contrast media and LMD-L were infused at a rate of 4 ml/s by an autoinjector. With regard to image quality, the prevalence of clear image segments was comparable between contrast media and LMD-L (97.9% vs. 96.5%, P=0.90). Furthermore, excellent correlations were observed between both flushing solutions in terms of minimum lumen area, mean lumen area, and mean stent area. The total volumes of contrast media and of LMD-L needed for OCT image acquisition were similar. CONCLUSIONS: FD-OCT image acquisition with LMD-L has the potential to reduce the total amount of contrast media without loss of image quality.

Optical coherence tomography-derived anatomical criteria for functionally significant coronary stenosis assessed by fractional flow reserve.

BACKGROUND: For the identification of functionally significant coronary artery disease, there have not been any dedicated optical coherence tomography (OCT) studies reported previously, although OCT can clearly detect coronary vessel lumina at higher resolution than intravascular ultrasound (IVUS). METHODS AND RESULTS: OCT and fractional flow reserve (FFR) measurements were performed in 62 intermediate coronary lesions in 59 patients. FFR was calculated as the ratio of distal coronary pressure divided by proximal coronary pressure during maximal hyperemia. FFR <0.75 was used as the threshold for diagnosing functionally significant stenosis. Minimal lumen area (MLA), minimal lumen diameter (MLD) and percent lumen area stenosis were measured by OCT. FFR values correlated significantly with OCT-derived MLA (r=0.75, P<0.01), MLD (r=0.76, P<0.01) and percent lumen area stenosis (r=-0.77, P<0.01). Receiver-operating characteristic curve suggested an OCT-derived MLA <1.91 mm(2) (sensitivity 93.5%, specificity 77.4%), MLD <1.35 mm (sensitivity 90.3%, specificity 80.6%) and percent lumen area stenosis >70.0% (sensitivity 96.8%, specificity 83.9%) as the best cutoff values for a FFR <0.75. CONCLUSIONS: Anatomical measurements of coronary stenosis obtained by OCT show significant correlation with FFR. OCT has the potential to predict functionally significant stenosis, although the present OCT-derived parameters were smaller than those reported in previous IVUS studies.

Prevalence and clinical significance of papillary muscle infarction detected by late gadolinium-enhanced magnetic resonance imaging in patients with ST-segment elevation myocardial infarction.

BACKGROUND: The frequency of papillary muscle infarction (PapMI) without rupture has not been fully investigated in vivo. Furthermore, the relationship between papillary muscle dysfunction and mitral regurgitation (MR) has been controversial in patients with ST-segment elevation myocardial infarction. Therefore, the aim of this study was to assess the frequency and clinical characteristics of PapMI without rupture using late gadolinium-enhanced magnetic resonance imaging (MRI) in patients with ST-segment elevation myocardial infarction. METHODS AND RESULTS: One hundred eighteen ST-segment elevation myocardial infarction patients with primary percutaneous coronary intervention underwent cardiac MRI twice 9±4 days and 8±1 months (n=104) after myocardial infarction. MR was categorized by echocardiography. Of these patients, 40% were found to have late gadolinium enhancement of papillary muscle, in which the posterior papillary muscle was involved more frequently than the anterior papillary muscle (77% versus 26%; P<0.001). PapMI was encountered more frequently in patients with left circumflex and right coronary artery lesions compared with left anterior descending artery lesion (78%, 48%, and 13%; P<0.001). By multiple logistic regression analysis, only coaptation height was identified as an independent predictor of the presence of MR. The second cardiac magnetic resonance imaging showed that the infarct size had a positive correlation with left ventricular end-diastolic volume (r=0.41, P<0.001) and that PapMI was not associated with left ventricular remodeling (P=0.31). Deterioration of MR was not observed in patients with PapMI. CONCLUSIONS: PapMI is more frequent than previously thought yet appears to have significant clinical latency. The size of the myocardial infarction, but not the presence of PapMI, seems to affect left ventricular remodeling, and PapMI is not obligatorily associated with MR.

Assessment by optical coherence tomography of stent struts across side branch. -Comparison of bare-metal stents and drug-elution stents.-.

BACKGROUND: Late stent thrombosis (LST) after drug-eluting stent (DES) implantation is a major clinical problem that has not been fully explained. Incomplete neointimal coverage of stent struts is an important morphometric predictor of LST, which may be associated with impaired healing and the absence of full coverage of struts at branch-point ostia. Optical coherence tomography (OCT) was performed to compare 3 types of stents placed across side branches. METHODS AND RESULTS: At 9-month follow-up, the neointimal coverage of the struts of 58 stents across a side branch was measured by OCT (bare metal (BMS), n = 20; sirolimus-eluting (SES), n = 23; paclitaxel-eluting (PES), n = 15). According to the diameter ratio of side branch to main vessel, the side branches were classified as either large (ratio > 0.33) or small (ratio ≤ 0.33). BMS had the lowest frequency of uncovered struts (29.4%) and the greatest neointimal thickness on the struts (123 ± 33 µm). Neointimal thickness on the struts was less for SES than for PES (72 ± 16 vs. 91 ± 22 µm, P = 0.009), but there was no difference in the frequency of uncovered struts (66.1% vs. 58.6%, P=0.493). For large side branches, the frequency of uncovered struts was greater than in the small group for SES (87.5% vs. 40.7%, P = 0.0002) and PES (83.3% vs. 18.2%; P = 0.0013); there was no significant difference for BMS (43.8% vs. 16.7%, P = 0.138). CONCLUSIONS: Neointimal coverage on struts across a side branch was less frequently observed in DES than in BMS, particularly in large side branches.

Impact of hinge motion on in-stent restenosis after sirolimus-eluting stent implantation.

BACKGROUND: A tortuous lesion with hinge motion is reportedly a risk factor for in-stent restenosis (ISR) after bare metal stent implantation. Sirolimus-eluting stents (SESs) implantation has dramatically reduced ISR. However, SES is a closed-cell design stent, which has low conformability and flexibility. Several studies have reported a relationship between tortuous lesions and stent fracture, which is one of the causes of ISR. The efficacy of SES in a tortuous lesion with hinge motion has not been fully evaluated. The aim of this study was to investigate the relationship between tortuous lesions and ISR after SES implantation. METHODS AND RESULTS: Three year clinical follow-up data after SES implantation, including 6-9 month scheduled follow-up coronary angiography in 399 consecutive patients with 537 lesions, were obtained. Δangle was defined as the difference in the angle of the target lesion between the diastole and systole before the procedure. The incidence of ISR was 8.2%. The mean maximal angle and Δangle were larger in the ISR group (47 ± 22° vs. 37 ± 21°, P=0.004 and 20 ± 13° vs. 13 ± 10°, P < 0.0001, respectively). Independent predictors of ISR were Δangle, hemodialysis, aortic ostium stenting, and diabetes mellitus. Hinge motion-associated ISR (Δangle ≥ 16°) occurred in 28 lesions: stent fracture in 9, stent recoil in 6, edge injury in 10, and others in 3. CONCLUSIONS: The amount of hinge motion in tortuous lesions should be considered in the selection of drug eluting stent types.

Virtual histology intravascular ultrasound compared with optical coherence tomography for identification of thin-cap fibroatheroma.

Virtual histology intravascular ultrasound (VH-IVUS) allows detailed assessment of plaque composition in the clinical setting. Optical coherence tomography (OCT) has been developed as a high-resolution imaging method, which might be a promising technique to identify thin-cap fibroatheroma (TCFA) in vivo. The purpose of the present study was to evaluate the diagnostic accuracy of VH-IVUS to identify TCFA as determined by OCT.We examined 96 target lesions in patients with stable angina pectoris by using VH-IVUS and OCT. VH-IVUS derived TCFA was defined as a focal necrotic core-rich lesion without evident overlying fibrous tissue. OCT derived TCFA was defined as a plaque with a fibrous cap of < 65 µm. VH-IVUS correctly identified 16 TCFA and 67 non-TCFA but misclassified 2 TCFA and 11 non-TCFA as determined by OCT. The sensitivity, specificity, and positive and negative predictive values of VH-IVUS to identify TCFA as determined by OCT were 89%, 86%, 59%, and 97%, respectively.VH-IVUS showed an acceptable sensitivity and specificity to identify TCFA as determined by OCT. Although the positive predictive value was low reflecting a high number of false positives, the negative predictive value was notably high. Our results suggest a potential role for VH-IVUS to exclude high risk lesions for future coronary events.

Serial angiographic findings and prognosis of stent fracture site without early restenosis after sirolimus-eluting stent implantation.

BACKGROUND: Stent fracture is one of the possible causes of in-stent restenosis after sirolimus-eluting stent (SES) implantation. However, long-term prognosis including late restenosis in stent fracture site without early restenosis remains unknown. The aim of this study is to investigate the risk of late restenosis at the stent fracture site without early restenosis after SES implantation. METHODS: We divided 366 patients with 490 lesions into 2 groups with or without stent fracture based on the first scheduled follow-up coronary angiography (fracture group, 21 lesions; nonfracture group, 469 lesions). The second scheduled follow-up coronary angiography (>15 months after SES implantation) was performed in 83 patients with 124 lesions. RESULTS: Target lesion revascularization due to late restenosis at the stent fracture site did not occur in the fracture group, but occurred in 5 lesions in the nonfracture group. At the first follow-up, minimal luminal diameter was significantly smaller and percentage diameter stenosis was significantly larger in the fracture group (1.98 ± 0.41 vs 2.52 ± 0.49 mm, P = .001 and 30.5% ± 13.1% vs 13.0% ± 8.8%, P < .0001, respectively). These differences were also present at the second follow-up (P = .01 and P = .007, respectively). In each group, there were no significant changes in minimal luminal diameter, percentage diameter stenosis, and late lumen loss between the first and second follow-up. CONCLUSIONS: Late restenosis was not observed in stent fracture sites without early restenosis during the midterm follow-up after SES implantation.

Advantage of next-generation frequency-domain optical coherence tomography compared with conventional time-domain system in the assessment of coronary lesion.

BACKGROUND: Intracoronary optical coherence tomography (OCT) is a high-resolution imaging modality used for evaluation of coronary lesion morphology. However, current time-domain OCT (TD-OCT) have a number of limitations with regard to both procedural usage and safety in the clinical setting. The next-generation frequency-domain OCT (FD-OCT), which has a much faster frame rate and pullback speed than TD-OCT, is expected to overcome these limitations. The aim of this study was to evaluate the feasibility and usability of next generation FD-OCT in the assessment of coronary lesions. METHODS: A comparison study was performed between FD-OCT and TD-OCT from the aspect of usability (set-up time), qualitatively (rate of clear image segment), and safety (adverse event) in 14 ischemic heart disease patients with 20 previously implanted coronary stents. RESULTS: The mean time of the OCT procedure in this study from setup to completion of image acquisition was 3.2 +/- 0.8 min for FD-OCT and 11.2 +/- 2.5 min for TD-OCT (P < 0.01). In qualitative image assessment, FD-OCT has the potential to yield a higher rate of clear image segments (CIS) than TD-OCT (99.4% vs. 80.8%, respectively; P < 0.01). In addition to these improved characteristics, there were no ischemic ECG changes or arrhythmia associated with FD-OCT. CONCLUSIONS: The next-generation intracoronary FD-OCT has better performance in the clinical setting and the potential to overcome several limitations of conventional TD-OCT systems.

Lipid-rich plaque and myocardial perfusion after successful stenting in patients with non-ST-segment elevation acute coronary syndrome: an optical coherence tomography study.

AIMS: Although some recent guidelines recommend an early invasive strategy for non-ST-segment elevation acute coronary syndrome (NSTEACS), several studies have failed to identify any benefit for very early intervention for NSTEACS. The no-reflow phenomenon may inhibit the expected benefit from very early recanalization for NSTEACS subjects. The aim of this study was to investigate whether optical coherence tomography (OCT) could predict no-reflow in patients with NSTEACS. METHODS AND RESULTS: This study comprised 83 consecutive patients with NSTEACS who underwent OCT and successful emergent primary stenting. On the basis of post-stent TIMI flow, patients were divided into two groups: no-reflow group (n = 14) and reflow group (n = 69). Thin-cap fibroatheroma (TCFA) was defined as a plaque presenting lipid content for >90 degrees , and with thinnest part of the fibrous cap measuring <70 microm. Thin-cap fibroatheroma were more frequently observed in the no-reflow group than in the reflow group (50% vs. 16%, P = 0.005). The frequency of the no-reflow phenomenon increases according to the size of the lipid arc in the culprit plaque. Final TIMI blush grade also deteriorated according to the increase in the lipid arc. A multivariable logistic regression model revealed that lipid arc alone was an independent predictor of no-reflow (odds ratio 1.018; CI 1.004-1.033; P = 0.01). CONCLUSION: Optical coherence tomography can predict no-reflow after percutaneous coronary intervention (PCI) in NSTEACS. The lipid contents of a culprit plaque may play a key role in damage to the microcirculation after PCI for NSTEACS. From our results, it is found that OCT is useful tool for stratifying risk for PCI for NSTEACS.

Morphology of exertion-triggered plaque rupture in patients with acute coronary syndrome: an optical coherence tomography study.

BACKGROUND: Plaque rupture and secondary thrombus formation play key roles in the onset of acute coronary syndrome (ACS). One pathological study suggested that the morphologies of plaque rupture differed between rest-onset and exertion-triggered rupture in men who experienced sudden death. The aim of the present study was to use optical coherence tomography to investigate the relationship in patients with ACS between the morphology of a ruptured plaque and the patient's activity at the onset of ACS. METHODS AND RESULTS: The study population was drawn from 43 consecutive ACS patients (with or without ST-segment elevation) who underwent optical coherence tomography and presented with a ruptured plaque at the culprit site. Patients were divided into a rest group and an exertion group on the basis of their activities at the onset of ACS. The thickness of the broken fibrous cap correlated positively with activity at the onset of ACS. The culprit plaque ruptured at the shoulder more frequently in the exertion group than in the rest group (rest 57% versus exertion 93%, P=0.014). The thickness of the broken fibrous cap in the exertion group was significantly higher than in the rest-onset group (rest onset: 50 microm [interquartile median 15 microm]; exertion: 90 microm [interquartile median 65 microm], P<0.01). CONCLUSIONS: The morphologies of exertion-triggered and rest-onset ruptured plaques differ in ACS patients. Our data suggest that a thin-cap fibroatheroma is a lesion predisposed to rupture both at rest and during the patient's day-to day activity, and some plaque rupture may occur in thick fibrous caps depending on exertion levels.

Predictors and prognosis of stent fracture after sirolimus-eluting stent implantation.

BACKGROUND: Stent fracture is a cause of in-stent restenosis (ISR) after sirolimus-eluting stent (SES) implantation, so this study investigated the incidence, predictors and prognosis of stent fracture. METHODS AND RESULTS: The 273 consecutive patients (364 lesions) after SES implantation and who had 6-9 month' scheduled follow-up coronary angiography (CAG) were divided into groups with and without stent fracture. Deltaangle was defined as the difference in the angle in the target lesion between diastole and systole before the procedure. The incidence of stent fracture was 4.9% (18 of 364 lesions). Deltaangle in the target lesion was larger in the fracture group (28.3 +/-11.5 degrees vs 12.3 +/-9.0 degrees , P<0.0001). Independent predictors of stent fracture were Deltaangle and total stent length. The rates of binary restenosis and target lesion revascularization (TLR) were higher in the fracture group (33% vs 4.0%, P=0.0002 and 28% vs 3.5%, P=0.0007, respectively). There were no major adverse cardiac events (MACE) in the fracture group during a mean 24-month follow-up after follow-up CAG. CONCLUSIONS: Predictors of stent fracture were Deltaangle and total stent length. Although stent fracture was associated with ISR and TLR, it was not associated with MACE during long-term follow-up.

Myocardial salvage for ST-elevation myocardial infarction with terminal QRS distortion and restoration of brisk epicardial coronary flow.

Recently, it has been reported that large infarcts associated with terminal QRS distortion (QRSDIS) on the admission electrocardiograms of patients with ST-elevation myocardial infarctions (STEMIs) may be caused by a failure to achieve thrombolysis in myocardial infarction (TIMI) grade 3 flow after primary percutaneous coronary intervention (PCI). However, the relationship between QRSDIS and final infarct size when TIMI grade 3 flow could be achieved by primary PCI is still unclear. Sixty-two consecutive patients with first anterior STEMI and who achieved TIMI grade 3 flow by primary PCI were classified into two groups according to the presence (Group A, n = 18) or absence (Group B, n = 44) of QRSDIS. Two weeks after the onset of acute myocardial infarction, Group A had a larger left ventricular (LV) end-systolic volume index (LVESVI) and a lower LV ejection fraction (LVEF) than Group B (LVESVI: 38 +/- 13 vs 31 +/- 12 ml/m(2), P = 0.025: LVEF: 42% +/- 10% vs 51% +/- 10%, P = 0.004). Through multivariate analysis, independent predictors of poor LV systolic function (LVEF < 40%) were determined to be the presence of QRSDIS (odds ratio 21.04, P = 0.021) and proximal left anterior descending artery occlusion (odds ratio 16.15, P = 0.033). Myocardial damage could not be reduced in patients experiencing STEMI with QRSDIS, even when TIMI grade 3 flow could be achieved by primary PCI, as much as in patients experiencing STEMI without QRSDIS.

Coronary superficial and spotty calcium deposits in culprit coronary lesions of acute coronary syndrome as determined by optical coherence tomography.

The characteristics of coronary artery calcium responsible for vulnerable plaque remain incompletely elucidated. We used optical coherence tomography to investigate the characteristics of coronary calcium in acute myocardial infarction (AMI), unstable angina pectoris (UAP), and stable angina pectoris (SAP). We evaluated calcium deposits in the culprit lesions (30-mm segment) using optical coherence tomography in 187 patients with AMI (n = 44), UAP (n = 73), or SAP (n = 70). The arc, area, and length of calcium were significantly smaller in those with AMI and UAP than in those with SAP (p <0.001). The number of spotty calcium deposits (with an arc of <90°) per patient was significantly larger in the AMI and UAP groups than in the SAP group (p <0.001). The number of large calcium deposits (with an arc of >90°) per patient was significantly lower in the AMI and UAP groups than in the SAP group (p <0.001). The minimum distance between the inner edge of the calcium and the luminal surface was significantly shorter in the AMI and UAP groups than in the SAP group (p <0.001). Plaque rupture frequency correlated positively with the number of spotty calcium deposits (r = 0.479, p <0.001) and inversely with the number of large calcium deposits (r = -0.219, p = 0.003). In conclusion, calcium was very spotty and more superficial in the culprit lesions of AMI and UAP. These characteristics of calcium might play an important role in the pathogenesis of plaque vulnerability.

Occlusion of left main coronary artery during percutaneous coronary intervention for chronic total occlusion of left circumflex artery with retrograde approach.

The retrograde approach, a new technique of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO), allows coronary interventionalists to improve the success rate. However, this technique occasionally has serious complications. We report a case with the occlusion of left main coronary artery (LMCA) during PCI for CTO in the proximal LCX with retrograde approach because of backward spiral dissection formed by retrograde wire. We could perform bail-out stenting for LMCA. In PCI for CTO in the proximal site of left coronary artery with retrograde approach, we should keep in mind a backward dissection to LMCA formed by retrograde wire.

Distribution, frequency and clinical implications of napkin-ring sign assessed by multidetector computed tomography.

BACKGROUND: Plaque rupture and secondary thrombus formation play key roles in the onset of acute coronary syndrome (ACS). Plaques showing the napkin-ring sign in multidetector computed tomography (MDCT) have been reported as thin-cap fibroatheroma that is recognized as a precursor lesion for plaque rupture. The purpose of this study was to investigate distribution and frequency of napkin-ring sign and its relationship to features indicating coronary plaque vulnerability on MDCT in patients with coronary artery disease. METHODS: We enrolled 273 patients with ACS (n=61) or stable angina pectoris (SAP, n=212) who were assessed by MDCT. The definition of the napkin-ring sign was the presence of a ring of high attenuation and the CT attenuation of a ring presenting higher than those of the adjacent plaque and no greater than 130HU. RESULTS: The culprit plaques with the napkin-ring sign show higher remodeling index and lower CT attenuation (1.15±0.12 vs. 1.02±0.12, p<0.01 and 39.9±22.8 vs. 72.7±26.6, p<0.01, respectively). Napkin-ring sign at culprit lesions was more frequent in patients with ACS than those with SAP (49.0% vs. 11.2%, p<0.01). Moreover, napkin-ring sign at non-culprit lesions was more frequently observed in ACS patients compared with SAP patients (12.7% vs. 2.8%, p<0.01). The distribution of the napkin-ring sign in the right coronary arteries and left circumflex arteries of our population was relatively even, whereas the napkin-ring sign in the left anterior descending artery was common in the proximal sites (p<0.01). CONCLUSIONS: The napkin-ring sign assessed by MDCT represents similar clinical features of fibroatheroma. MDCT could contribute to the search for fibroatheroma.

Difference in neointimal appearance between early and late restenosis after sirolimus-eluting stent implantation assessed by optical coherence tomography.

OBJECTIVES: Late in-stent restenosis (ISR) is an important clinical issue in the drug-eluting stent era. Autopsy studies have reported different underlying mechanisms between early ISR and late ISR. The aim of the present study was to compare the neointimal tissue appearance between early ISR (<1 year) and late ISR (>1 year) after sirolimus-eluting stent (SES) implantation using optical coherence tomography (OCT). MATERIALS AND METHODS: We examined the neointimal tissue appearance in 48 ISR lesions after SES implantation [30 early ISR lesions (8±1 months after stenting) and 18 late ISR lesions (34±14 months after stenting)] by OCT. ISR was defined as percent diameter stenosis more than 50% within the stented segment in angiography. Lipid-rich neointima was characterized by signal-poor regions with diffuse borders. Thin-cap fibroatheroma (TCFA)-like neointima was defined by lipid-rich neointima with cap thickness 65 µm or less. RESULTS: In the OCT findings, heterogeneous neointima was more often observed in the late ISR group compared with the early ISR group (89 vs. 43%, P=0.002). Although the frequency of intraluminal thrombus was not different between the two groups (P=0.085), the frequency of lipid-rich neointima (83 vs. 27%, P<0.001), TCFA-like neointima (39 vs. 10%, P=0.028), microchannels within neointima (67 vs. 27%, P=0.007), and neointimal disruption (33 vs. 3%, P=0.008) was significantly higher in the late ISR group. CONCLUSION: In the present OCT study, it was found that atherosclerotic progression of neointima, such as lipid-rich neointima, TCFA-like neointima, microchannels, and neointimal disruption, was more often observed in late ISR lesions after SES implantation compared with early ISR ones.