Optical Coherence Tomography Findings in Patients With Coronary Stent Thrombosis: A Report of the PRESTIGE Consortium (Prevention of Late Stent Thrombosis by an Interdisciplinary Global European Effort).

BACKGROUND: Stent thrombosis (ST) is a serious complication following coronary stenting. Intravascular optical coherence tomography (OCT) may provide insights into mechanistic processes leading to ST. We performed a prospective, multicenter study to evaluate OCT findings in patients with ST. METHODS: Consecutive patients presenting with ST were prospectively enrolled in a registry by using a centralized telephone registration system. After angiographic confirmation of ST, OCT imaging of the culprit vessel was performed with frequency domain OCT. Clinical data were collected according to a standardized protocol. OCT acquisitions were analyzed at a core laboratory. Dominant and contributing findings were adjudicated by an imaging adjudication committee. RESULTS: Two hundred thirty-one patients presenting with ST underwent OCT imaging; 14 (6.1%) had image quality precluding further analysis. Of the remaining patients, 62 (28.6%) and 155 (71.4%) presented with early and late/very late ST, respectively. The underlying stent type was a new-generation drug-eluting stent in 50.3%. Mean reference vessel diameter was 2.9±0.6 mm and mean reference vessel area was 6.8±2.6 mm2. Stent underexpansion (stent expansion index <0.8) was observed in 44.4% of patients. The predicted average probability (95% confidence interval) that any frame had uncovered (or thrombus-covered) struts was 99.3% (96.1-99.9), 96.6% (92.4-98.5), 34.3% (15.0-60.7), and 9.6% (6.2-14.5) and malapposed struts was 21.8% (8.4-45.6), 8.5% (4.6-15.3), 6.7% (2.5-16.3), and 2.0% (1.2-3.3) for acute, subacute, late, and very late ST, respectively. The most common dominant finding adjudicated for acute ST was uncovered struts (66.7% of cases); for subacute ST, the most common dominant finding was uncovered struts (61.7%) and underexpansion (25.5%); for late ST, the most common dominant finding was uncovered struts (33.3%) and severe restenosis (19.1%); and for very late ST, the most common dominant finding was neoatherosclerosis (31.3%) and uncovered struts (20.2%). In patients presenting very late ST, uncovered stent struts were a common dominant finding in drug-eluting stents, and neoatherosclerosis was a common dominant finding in bare metal stents. CONCLUSIONS: In patients with ST, uncovered and malapposed struts were frequently observed with the incidence of both decreasing with longer time intervals between stent implantation and presentation. The most frequent dominant observation varied according to time intervals from index stenting: uncovered struts and underexpansion in acute/subacute ST and neoatherosclerosis and uncovered struts in late/very late ST.

Impact of Culprit Plaque and Atherothrombotic Components on Incomplete Stent Apposition in Patients With ST-Elevation Myocardial Infarction Treated With Everolimus-Eluting Stents　- An OCTAVIA Substudy.

BACKGROUND: The role of culprit plaque and related atherothrombotic components on incomplete stent apposition (ISA) occurrence after primary percutaneous coronary intervention (p-PCI) is unknown. METHODS AND RESULTS: ST-segment elevation myocardial infarction (STEMI) patients undergoing p-PCI with an everolimus-eluting stent were prospectively investigated with optical coherence tomography (OCT) of the infarct-related artery before, after stenting and at 9 months. OCT data, aspirated thrombus and serum inflammatory biomarkers were analyzed. 114 patients with 114 lesions were evaluated. Acute ISA occurred in 82 lesions (71.9%), preferentially in larger vessels with a median area of 0.2 mm(2). The presence of thrombus before stent implantation (odds ratio (OR) 5.5, 95% confidence interval (CI) [1.1-26.9], P=0.04) and the lipid content in the target segment (OR 1.3, 95% CI [1.0-1.5], P=0.04) independently predicted acute ISA. At 9-month follow-up, ISA persisted in 46 lesions (56.1%). The volume of acute ISA significantly predicted persistent ISA (OR 1.3, 95% CI [1.1-1.5], P=0.01). Late-acquired ISA occurred in 39 lesions (34.2%) with a median area of 0.3 mm(2). Red/mixed thrombus before stent implantation (OR 3.7, 95% CI [1.0-13.3], P=0.05) and length of the underlying ruptured plaque (OR 1.7, 95% CI [1.1-2.8] P=0.02) were independently associated with late-acquired ISA. CONCLUSIONS: In STEMI patients, culprit plaque and atherothrombotic components of the infarct-related artery significantly contribute to the onset of acute and late ISA. ISA persistence at follow-up depends on the initial volume of acute ISA.

High-density lipoprotein cholesterol level is associated with fibrous cap thickness in acute coronary syndrome.

BACKGROUND: Although low high-density lipoprotein cholesterol (HDL-C) level has been reported as an independent risk factor for coronary artery disease, few studies addressed the direct relationship between the presence of thin-cap fibroatheroma (TCFA) that is considered as vulnerable plaque in pathology and HDL-C level. The aim of this study was to investigate whether lesion vulnerability is related to HDL-C level in patients with acute coronary syndrome (ACS). METHODS AND RESULTS: A total of 261 patients with ACS who underwent optical coherence tomography prior to percutaneous coronary intervention, were enrolled. Patients were divided into a TCFA group (n=124) and a non-TCFA group (n=137). TCFA was defined as a lipid plaque (lipid content in ≥1 quadrant) covered with <70 µm-thickness fibrous caps. There were no differences in patient characteristics and clinical results between the 2 groups except for HDL-C level, low-density lipoprotein cholesterol (LDL-C) level, and high-sensitive C-reactive protein (hs-CRP) level. On multivariate regression analysis, low HDL-C level (ß coefficient: 0.302, P<0.001), high LDL-C level (ß coefficient: -0.172, P=0.008), hs-CRP level (ß coefficient: -0.145, P=0.017), and current smoking (ß coefficient: -0.124, P=0.028) were identified as independent contributors to fibrous cap thickness. CONCLUSIONS: HDL-C is correlated with fibrous cap thickness of the culprit lesion in patients with ACS. HDL-C may be considered as a therapeutic target for plaque stabilization.

Altered coronary flow velocity reserve and left ventricular wall motion dynamics: a phenomenon in hypertensive patients with ECG strain.

BACKGROUND: The inner-half layer of the left ventricular (LV) wall is primarily affected by ischemia and increased LV afterload. We hypothesized that LV wall thickening of inner-half layer and coronary microvascular function are impaired in hypertensive patients, especially in those with electrocardiographic (ECG) strain, which is a marker of LV hypertrophy and adverse prognosis. Therefore, the aim of this study is to investigate the association of the ratio of inner- to outer-half layer of the LV myocardial deformation and coronary microvascular function with ECG strain in hypertensive patients. METHODS: We studied 98 hypertensive patients and 13 controls. Hypertensive patients were divided into 2 groups, with (S+) and without (S-) ECG strain. Coronary flow velocity reserve (CFVR) of the left anterior descending artery was evaluated using transthoracic echocardiography. Circumferential and radial strains of the LV wall were analyzed by two-dimensional echocardiographic speckle tracking method, and the inner- to outer-half layer ratio (in/out ratio) was assessed. RESULTS: Coronary flow velocity reserve of S+ (2.06 ± 0.65) was significantly smaller than those in S- and controls (3.03 ± 0.65 and 3.38 ± 0.51, respectively). In/out ratio in both circumferential and radial strains were decreased as well as in S+ patients. Furthermore, in/out ratio was directly proportional to CFVR. CONCLUSIONS: Hypertensive patients with ECG strain possessed severely impaired CFVR and inner-half myocardial deformation. Moreover, the more severe the LV hypertrophy progresses, the greater is the impairment of coronary microvascular and LV inner-half myocardial deformation. Thus, CFVR and in/out ratio are useful quantitative markers that can render sensitive assessment of physiological changes in hypertensive heart disease.

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.

Circulating CD14+CD16+ monocyte subsets as biomarkers of the severity of coronary artery disease in patients with stable angina pectoris.

BACKGROUND: Circulating monocytes can be divided into 2 subsets typically identified by the expression of CD14 and CD16. Although previous studies have shown that circulating monocytes contribute to the progression of coronary atherosclerotic lesions, the relationship between the severity of coronary artery disease (CAD) and the 2 distinct monocyte subsets has not previously been evaluated. We investigated the relationship between the monocyte subsets and the severity of CAD assessed by coronary angiography (CAG) in patients with stable angina pectoris (SAP). METHODS AND RESULTS: We enrolled 125 patients who underwent diagnostic CAG. Patients were divided into 3 groups: those without CAD, those with single-vessel disease (SVD), and those with multiple-vessel disease (MVD). In addition, the severity of CAD was evaluated by Gensini score. The 2 monocyte subsets (CD14(+)CD16(-) and CD14(+)CD16(+)) were measured by flow cytometry. Circulating CD14(+)CD16(+) monocytes were more frequently observed in patients with MVD than in those with SVD or without CAD. The proportion of CD14(+)CD16(+) monocytes positively correlated with Gensini score (r=0.618, P<0.001). Multivariate logistic regression analysis revealed that the proportion of CD14(+)CD16(+) monocytes was an independent contributor to MVD (odds ratio: 1.475; 95% confidence interval: 1.273-1.708, P<0.001). CONCLUSIONS: A preferential increase in peripheral CD14(+)CD16(+) monocytes may be closely related to the severity of CAD in patients with SAP.

Impact of stress hyperglycemia on myocardial salvage following successfully recanalized primary acute myocardial infarction.

BACKGROUND: Elevated blood glucose on admission may worsen outcome after acute myocardial infarction (AMI). No relationship has been identified between admission blood glucose level and myocardial salvage in patients with AMI. METHODS AND RESULTS: This study assessed 150 consecutive patients with a first AMI who underwent percutaneous coronary intervention within 24 h from onset of symptoms. Plasma blood glucose was measured on admission. Stress hyperglycemia was defined as blood glucose ≥10 mmol/L (180 mg/dl). The extent of myocardial salvage 7 days after AMI was evaluated on cardiovascular magnetic resonance imaging (CMRI) as the difference between areas of myocardium at risk (T2-weighted hyperintense lesion) and areas of late gadolinium enhancement. The association between stress hyperglycemia and myocardial salvage index (MSI) was investigated in patients with and without diabetes. Among non-diabetic patients, MSI was lower in those with stress hyperglycemia than in those without. No significant difference in MSI was noted between diabetes patients with or without stress hyperglycemia. On multivariate analysis, stress hyperglycemia in patients without diabetes was an independent predictor of MSI. CONCLUSIONS: Stress hyperglycemia affects MSI, indicating that the manipulation of glucose levels could be a potential therapeutic target for salvaging ischemic damage.

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.

Effect of direct renin inhibitor, aliskiren, on peripheral blood monocyte subsets and myocardial salvage in patients with primary acute myocardial infarction.

BACKGROUND: It remains unclear whether angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II type 1 receptor blockers (ARBs) have fully delivered the expected reduction in cardiovascular diseases. We investigated the effects of adding the direct renin inhibitor (DRI), aliskiren, to an ACEI or an ARB on monocyte subsets and myocardial salvage in patients with primary acute myocardial infarction (AMI). METHODS AND RESULTS: Twenty-one consecutive patients were treated with an ACEI or an ARB (non-DRI group), and another 21 consecutive patients received aliskiren combined with an ACEI or an ARB (DRI group). Two monocyte subsets (CD14(+)CD16(-) and CD14(+)CD16(+)) were measured by flow cytometry. The extent of myocardial salvage 7 days after AMI was evaluated by cardiac magnetic resonance imaging. Both plasma renin activity and aldosterone levels were significantly lower in the DRI group than in the non-DRI group. Peak levels of CD14(+)CD16(-) monocyte number and ratio were also significantly lower in the DRI group. The extent of myocardial salvage was significantly higher in the DRI group than in the non-DRI group (44.8 [41.2-53.1] vs. 36.0 [28.5-42.6], P=0.001). CONCLUSIONS: A DRI combined with an ACEI or an ARB can better improve the extent of myocardial salvage after AMI than an ACEI or an ARB alone in association with the decrease in circulating CD14(+)CD16(-) monocytes.

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.

[Assessment of vulnerable plaque and vulnerable patient by optical coherence tomography].

Optical coherence tomography (OCT) is an intravascular imaging modality, which provides high resolution images up to 10-20 microm. This feature of OCT allows the visualization of specific components of the atherosclerotic plaques in vivo, similar to the histological examinations in vitro. OCT has made a great contribution to the investigation of the pathophysiology of acute coronary syndrome (ACS) in vivo. Furthermore, OCT has a potential not only to detect vulnerable plaques but also to identify vulnerable patients, and may enable us to predict and prevent ACS in the near future.

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.

Upregulation of fractalkine and its receptor, CX3CR1, is associated with coronary plaque rupture in patients with unstable angina pectoris.

BACKGROUND: Recent studies suggest that fractalkine (FKN or CX3CL1) and its cognate receptor, CX3CR1, play a role in atherogenesis, so the relationship between coronary plaque rupture, as observed by preintervention optical coherence tomography, and plasma levels of FKN and CX3CR1 was investigated in this study. METHODS AND RESULTS: The study population consisted of 46 patients with unstable angina pectoris (UAP), 30 patients with stable angina pectoris, and 25 healthy controls. The UAP patients underwent a preintervention optical coherence tomography study, which revealed that the number of patients with and without plaque rupture at the culprit site was 27 (rupture group) and 19 (non-rupture group), respectively. Plasma levels of soluble FKN (sFKN) and CX3CR1 were measured by enzyme-linked immunosorbent assay and flow cytometry, respectively. The plasma levels of sFKN were significantly increased in UAP patients with plaque rupture compared with patients in the other groups. Multiple logistic regression analysis showed that CD14(+)CD16(+)CX3CR1(+) monocytes and CD3(+)CX3CR1(+) lymphocytes were independent predictors of the presence of ruptured plaque. CONCLUSIONS: Increases in the FKN level and the number of CX3CR1-expressing mononuclear cells might contribute to coronary plaque rupture.

Post-reperfusion enhancement of CD14(+)CD16(-) monocytes and microvascular obstruction in ST-segment elevation acute myocardial infarction.

BACKGROUND: The presence of microvascular obstruction (MVO) after primary ST-segment elevation acute myocardial infarction (STEMI) is associated with a poor outcome. The aim of the paper was to examine the relationship between distinct monocyte subsets and gadolinium-enhanced cardiovascular magnetic resonance (CMR) characteristics of MVO after STEMI. METHODS AND RESULTS: Seventy-one patients with primary STEMI successfully treated with stenting were enrolled in the study. Two monocyte subsets (CD14(+)CD16(-) and CD14(+)CD16(+)) were measured on flow cytometry on admission and 2, 3, 4, 5, 8 days after the onset of STEMI. CMR was performed 7 days after revascularization to determine MVO on late gadolinium-enhanced imaging. The peak levels of CD14(+)CD16(-) monocytes, but not those of CD14(+)CD16(+) monocytes, were significantly higher in patients with MVO than in those without MVO. A multivariate logistic regression model showed that the post-perfusion peak levels of CD14(+)CD16(-) monocytes remained an independent factor for the presence of MVO (odds ratio=1.53; 95% confidence interval: 1.01-2.32; P=0.04). The absence of MVO was significantly associated with improvement in left ventricular ejection fraction. CONCLUSIONS: Post-reperfusion enhancement of CD14(+)CD16(-) monocytes was associated with MVO in patients with STEMI. The pathophysiologic and therapeutic implications of this association require further study.