Shiro Uemura

In vivo diagnosis of plaque erosion and calcified nodule in patients with acute coronary syndrome by intravascular optical coherence tomography.

OBJECTIVES The aim of this study was to characterize the morphological features of plaque erosion and calcified nodule in patients with acute coronary syndrome (ACS) by optical coherence tomography (OCT). BACKGROUND Plaque erosion and calcified nodule have not been systematically investigated in vivo. METHODS A total of 126 patients with ACS who had undergone pre-intervention OCT imaging were included. The culprit lesions were classified as plaque rupture (PR), erosion (OCT-erosion), calcified nodule (OCT-CN), or with a new set of diagnostic criteria for OCT. RESULTS The incidences of PR, OCT-erosion, and OCT-CN were 43.7%, 31.0%, and 7.9%, respectively. Patients with OCT-erosion were the youngest, compared with those with PR and OCT-CN (53.8 ± 13.1 years vs. 60.6 ± 11.5 years, 65.1 ± 5.0 years, p = 0.005). Compared with patients with PR, presentation with non-ST-segment elevation ACS was more common in patients with OCT-erosion (61.5% vs. 29.1%, p = 0.008) and OCT-CN (100% vs. 29.1%, p < 0.001). The OCT-erosion had a lower frequency of lipid plaque (43.6% vs. 100%, p < 0.001), thicker fibrous cap (169.3 ± 99.1 μm vs. 60.4 ± 16.6 μm, p < 0.001), and smaller lipid arc (202.8 ± 73.6° vs. 275.8 ± 60.4°, p < 0.001) than PR. The diameter stenosis was least severe in OCT-erosion, followed by OCT-CN and PR (55.4 ± 14.7% vs. 66.1 ± 13.5% vs. 68.8 ± 12.9%, p < 0.001). CONCLUSIONS Optical coherence tomography is a promising modality for identifying OCT-erosion and OCT-CN in vivo. The OCT-erosion is a frequent finding in patients with ACS, especially in those with non-ST-segment elevation ACS and younger patients. The OCT-CN is the least common etiology for ACS and is more common in older patients. (The Massachusetts General Hospital Optical Coherence Tomography Registry; NCT01110538).

OCT-Based Diagnosis and Management of STEMI Associated With Intact Fibrous Cap

In autopsy studies, at least 25% of thrombotic coronary occlusions are caused by plaque erosion in which thrombus often overlies atherosclerotic plaque without evident disruption of the fibrous cap. We performed optical coherence tomography imaging after aspiration thrombectomy and identified plaque erosion as the cause in 31 patients presenting with ST-segment elevation myocardial infarction. Plaque erosion was identified when the fibrous cap of the culprit lesion was intact. Based on clinical criteria, 40% of patients with subcritically occlusive plaque were treated with dual antiplatelet therapy without percutaneous revascularization (group 1), and the remaining 60% of patients underwent angioplasty and stenting (group 2). At a median follow-up of 753 days, all patients were asymptomatic, regardless of stent implantation. These observations support an alternative treatment strategy for patients with acute coronary events and optical coherence tomography-verified intact fibrous cap (or plaque erosion), where nonobstructive lesions might be managed without stenting.

Incidence and Clinical Significance of Poststent Optical Coherence Tomography Findings One-Year Follow-Up Study From a Multicenter Registry

Background— Optical coherence tomography (OCT) was recently introduced to optimize percutaneous coronary intervention. However, the exact incidence and significance of poststent OCT findings are unknown. Methods and Results— A total of 900 lesions treated with 1001 stents in 786 patients who had postprocedure OCT imaging were analyzed to evaluate the incidence of poststent OCT findings and to identify the OCT predictors for device-oriented clinical end points, including cardiac death, target vessel–related myocardial infarction, target lesion revascularization, and stent thrombosis. Patients were followed up to 1 year. Stent edge dissection was detected in 28.7% of lesions, and incomplete stent apposition was detected in 39.1% of lesions. The incidences of smooth protrusion, disrupted fibrous tissue protrusion, and irregular protrusion were 92.9%, 61.0%, and 53.8%, respectively. Small minimal stent area, defined as a lesion with minimal stent area <5.0 mm2 in a drug-eluting stent or <5.6 mm2 in a bare metal stent, was observed in 40.4% of lesions. One-year device-oriented clinical end points occurred in 33 patients (4.5%). Following adjustment, irregular protrusion and small minimal stent area were independent OCT predictors of 1-year device-oriented clinical end points (P=0.003 and P=0.012, respectively). Conclusions— Abnormal poststent OCT findings were frequent. Irregular protrusion and small minimal stent area were independent predictors of 1-year device-oriented clinical end points, which were primarily driven by target lesion revascularization.Background— Optical coherence tomography (OCT) was recently introduced to optimize percutaneous coronary intervention. However, the exact incidence and significance of poststent OCT findings are unknown. Methods and Results— A total of 900 lesions treated with 1001 stents in 786 patients who had postprocedure OCT imaging were analyzed to evaluate the incidence of poststent OCT findings and to identify the OCT predictors for device-oriented clinical end points, including cardiac death, target vessel–related myocardial infarction, target lesion revascularization, and stent thrombosis. Patients were followed up to 1 year. Stent edge dissection was detected in 28.7% of lesions, and incomplete stent apposition was detected in 39.1% of lesions. The incidences of smooth protrusion, disrupted fibrous tissue protrusion, and irregular protrusion were 92.9%, 61.0%, and 53.8%, respectively. Small minimal stent area, defined as a lesion with minimal stent area <5.0 mm2 in a drug-eluting stent or <5.6 mm2 in a bare metal stent, was observed in 40.4% of lesions. One-year device-oriented clinical end points occurred in 33 patients (4.5%). Following adjustment, irregular protrusion and small minimal stent area were independent OCT predictors of 1-year device-oriented clinical end points ( P =0.003 and P =0.012, respectively). Conclusions— Abnormal poststent OCT findings were frequent. Irregular protrusion and small minimal stent area were independent predictors of 1-year device-oriented clinical end points, which were primarily driven by target lesion revascularization. # CLINICAL PERSPECTIVE {#article-title-35}

Nonculprit Coronary Plaque Characteristics of Chronic Kidney Disease

Background— Chronic kidney disease (CKD) promotes the development of atherosclerosis and increases the risk of cardiovascular disease. The aim of the present study was to compare the coronary plaque characteristics of patients with and without CKD using optical coherence tomography. Methods and Results— We identified 463 nonculprit plaques from 287 patients from the Massachusetts General Hospital (MGH) optical coherence tomography registry. CKD was defined as estimated glomerular filtration rate <60 mL/min per 1.73 m2. A total of 402 plaques (250 patients) were in the non-CKD group and 61 plaques (37 patients) were in the CKD group. Compared with non-CKD plaques, plaques with CKD had a larger lipid index (mean lipid arc×lipid length, 1248.4±782.8 mm° [non-CKD] versus 1716.1±1116.2 mm° [CKD]; P=0.003). Fibrous cap thickness was not significantly different between the groups. Calcification (34.8% [non-CKD] versus 50.8% [CKD]; P=0.041), cholesterol crystals (11.2% [non-CKD] versus 23.0% [CKD]; P=0.048), and plaque disruption (5.5% [non-CKD] versus 13.1% [CKD]; P=0.049) were more frequently observed in the CKD group. In the multivariate linear regression model, a lower estimated glomerular filtration rate and diabetes mellitus were independent risk factors for a larger lipid index. Conclusions— Compared with non-CKD patients, the patients with CKD had a larger lipid index with a higher prevalence of calcium, cholesterol crystals, and plaque disruption. The multivariate linear regression model demonstrated that a lower estimated glomerular filtration rate was an independent risk factor for a larger lipid index. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01110538.

Colocalization of thin-cap fibroatheroma and spotty calcification is a powerful predictor of procedure-related myocardial injury after elective coronary stent implantation.

ObjectivesPercutaneous coronary intervention (PCI)-related cardiac enzyme elevation is an independent risk factor for adverse clinical outcomes, but preprocedural predictors of this complication have not been established. This study evaluated the morphological characteristics of culprit lesions by frequency-domain optical coherence tomography (FD-OCT), and examined their predictive value for procedure-related myocardial injury in patients undergoing elective PCI. MethodsSixty-eight patients treated by FD-OCT-guided elective PCI were studied. On the basis of the presence or absence of postprocedural plasma cardiac troponin T (cTnT) elevation, patients were divided into elevation (cTnT-E, n=25) and nonelevation (cTnT-nonE, n=43) groups. FD-OCT examinations of culprit lesions were performed before and after stent implantation, and tissue characteristics were evaluated within a 10-mm-long segment of each lesion. ResultsClinical parameters were similar between the two groups. Stent length was significantly longer in the cTnT-E group than in the cTnT-nonE group. On baseline OCT images, thin-cap fibroatheroma and calcium deposition were more frequently observed within culprit segments of the cTnT-E group compared with the cTnT-nonE group (32.0 vs. 11.6%, P=0.043, and 72.0 vs. 46.5%, P=0.039, respectively). In addition, colocalization of these two findings was a powerful predictor of PCI-related cTnT elevation (odds ratio 8.40, 95% confidence interval 1.65–52.78, P<0.01). Further, the predictive value of this colocalization was enhanced when the analysis included only spotty calcification (odds ratio 21.00, 95% confidence interval 2.65–454.22, P=0.003). ConclusionFD-OCT examination showed that colocalization of thin-cap fibroatheroma and spotty calcification was a powerful predictor of PCI-related cTnT elevation. FD-OCT is useful for stratifying risk during PCI to avoid procedure-related complications.

Side branch complication after a single-stent crossover technique: prediction with frequency domain optical coherence tomography.

ObjectivesTo identify preprocedural predictors of side branch (SB) complications after coronary bifurcation stent implantation using frequency domain optical coherence tomography (FD-OCT). BackgroundCoronary bifurcation lesions are common but difficult to treat. Longitudinal reconstruction images of FD-OCT have high image quality and less motion artifacts. MethodsAmong 49 patients (age: 69.9 years) who underwent elective coronary stenting, 52 bifurcation lesions without baseline SB stenosis were studied. SB complication was defined as angiographic worsening of SB stenosis (>75%). On the basis of preprocedural FD-OCT imaging, plaque distribution, SB angle, carina tip angle (CT angle), and length between proximal branching point to carina tip (BP-CT length) were evaluated. ResultsSB complication was observed in 22 lesions. The eccentric plaque distribution oriented toward the opposite side of SB at the CT was significantly more frequent in lesions with SB complication compared with those without (77.3 vs. 16.7%, P<0.01). CT angle and BP-CT length were significantly smaller in lesions with SB complication compared with those without [29.5° (interquartile range (IQR) 22.3–44.3°) vs. 65.0° (IQR 42.5–90.0°)], P<0.001; 1.20 mm (IQR 0.70–1.73 mm) vs. 2.25 mm (IQR 1.78–3.20 mm), P<0.001, respectively]. The receiver-operating characteristic curve indicated a CT angle less than 50° (area under the curve=0.81, sensitivity 86%, specificity 70%) and BP-CT length less than 1.70 mm (area under the curve=0.84, sensitivity 77%, specificity 77%) as the best cutoff values for predicting the SB complication after main vessel stent implantation. ConclusionThis FD-OCT study showed that narrower CT angle and shorter BP-CT length were the independent predictors for SB complications after bifurcation stenting.

Insights into the spatial distribution of lipid-rich plaques in relation to coronary artery bifurcations: An in-vivo optical coherence tomography study

Objectives The aim of this study was to investigate the spatial location of vulnerable plaques at coronary artery bifurcations using frequency domain-optical coherence tomography. Background In-vivo data on geometric location of vulnerable plaques in relation to coronary bifurcation are limited. Materials and methods A total of 40 patients with left anterior descending artery bifurcation were studied. Plaque characteristics in five regions in relation to a side branch were compared: opposite flow divider (OFD); bifurcation site (BF); main branch side proximal (MBP); side branch side proximal (SBP); and flow divider (FD). Frequency domain-optical coherence tomography was used for plaque characterization. Results Seventy-two lipid-rich plaques and 15 thin-cap fibroatheroma (TCFA) were detected in 220 regions of 44 bifurcations. Overall, the main branch side had more vulnerable characteristics compared with the side branch side. The FD was rarely affected by lipid accumulation. The OFD showed the highest prevalence of lipid-rich plaques [47.7% (OFD) vs. 45.5% (MBP), 43.2% (BF), 18.2% (SBP), and 9.1% (FD), P<0.0001] and TCFA [20.5% (OFD) vs. 6.8% (MBP), 6.8% (BF), 2.2% (SBP), and 0.0% (FD), P<0.001] and the thinnest fibrous cap [88.7±43.7 &mgr;m (OFD) vs. 123.5±62.7 &mgr;m (MBP), 149.6±77.0 &mgr;m (BF), 157.4±65.4 &mgr;m (SBP), and 163.6±76.9 &mgr;m (FD), P=0.002] compared with other regions. Conclusion Lipid accumulation tends to develop in the zone opposite the side branch. TCFA was localized predominantly in the region OFD, whereas FD was rarely affected.

Comparison of Neoatherosclerosis and Neovascularization Between Patients With and Without Diabetes: An Optical Coherence Tomography Study

OBJECTIVES This study aimed to investigate the characteristics of neoatherosclerosis (NA) in patients with diabetes mellitus (DM) after drug-eluting stent (DES) implantation using optical coherence tomography. BACKGROUND NA is an important substrate for stent failure. In vivo NA characteristics in DM patients have not been investigated. METHODS A total of 397 patients with 452 DES who underwent follow-up optical coherence tomography examination after DES implantation were enrolled. Characteristics of NA were compared between DM and non-DM patients. Neovascularization was defined as signal-poor holes or tubular structures with a diameter of 50 to 300 μm. RESULTS A total of 123 DES with NA lesions in 115 patients were identified. The incidence of NA was similar between DM and non-DM patients (29.6% vs. 28.6%; p = 0.825). Compared with the non-DM group, neovascularization was more frequently observed in the DM group (55.1% vs. 32.4%; p = 0.012). The multivariate logistic model demonstrated that DM (odds ratio: 3.00; 95% confidence interval: 1.31 to 6.81; p = 0.009) and follow-up duration (odds ratio: 1.03; 95% confidence interval: 1.02 to 1.05; p < 0.001) were the independent predictors for neovascularization in NA lesions. DM patients with glycated hemoglobin ≥7.0% had a higher prevalence of thin-cap fibroatheroma compared with those with glycated hemoglobin <7.0% (40.0% vs. 8.3%; p = 0.01). CONCLUSIONS The incidence of NA was similar between patients with and without DM. Neovascularization in NA lesions was more frequent in those with DM. Poorly controlled DM patients had a higher incidence of thin-cap fibroatheroma, compared with those with well-controlled DM.

In-stent neointimal characteristics and late neointimal response after drug-eluting stent implantation: A preliminary observation

BACKGROUND Progressive neointimal proliferation may lead to late restenosis and/or neoatherosclerosis after drug-eluting stent (DES) implantation. Late neointimal response may be different among different tissue characteristics. The aim of this study was to assess impact of in-stent neointimal characteristics on late neointimal response following DES implantation. METHODS Serial (median 270 days and median 551 days after stent implantation) optical coherence tomography (OCT) examinations were performed in 42 stented lesions from 26 patients. In-stent neointimal tissue was categorized as either homogeneous or heterogeneous neointima based on the OCT appearance at 1st follow-up. Serial changes in neointimal area (NIA) were compared between lesions with homogeneous neointima and those with heterogeneous neointima. RESULTS At first follow-up, homogeneous neointima was observed in 22 (52%) and heterogeneous neointima in 20 (48%) lesions, respectively. During follow-up, NIA in lesions with homogeneous neointima decreased significantly (1.8±0.93 mm(2) to 1.5±0.88 mm(2), p<0.001). On the other hand, NIA in lesions with heterogeneous neointima did not change significantly (2.7±1.8 mm(2) to 2.8±1.6 mm(2), p=0.658). Homogeneous neointima was the only predictor of late neointimal regression (late neointimal regression defined as NIA at first follow-up - NIA at second follow-up <0) by multivariable analysis (odds ratio=7.591, 95% confidence interval: 1.616-35.67, p=0.010). CONCLUSIONS OCT characteristics of neointima after DES implantation may be related to late neointimal progression or regression.

In vivo assessment of vasa vasorum neovascularization using intravascular ultrasound: A comparison between acute coronary syndrome and stable angina pectoris

BACKGROUND Previous studies have suggested that vasa vasorum (VV) neovascularization plays an important role in the progression and vulnerability of coronary atherosclerotic plaque. METHODS A total of 130 patients with coronary artery disease including 75 acute coronary syndrome (ACS) cases and 55 stable angina pectoris (SAP) cases were studied. By using intravascular ultrasound (IVUS), VV was defined as a small (<1mm) tubular or vesicular, low-echoic structure observed exterior to the media. Prevalence and maximal number of VV were compared between patients with ACS versus SAP. RESULTS The prevalence of VV at the culprit lesion was similar between the 2 groups (97% vs. 93%, p=0.216). On the other hand, it was significantly higher in ACS than SAP at both reference sites (proximal: 93% vs. 81%, p=0.047 and distal: 88% vs. 60%, p<0.001, respectively). The maximum number of VV was significantly higher in ACS than in SAP (at the culprit lesion: 2.8±1.3 vs. 1.8±1.0, p<0.001, at the proximal reference: 1.9±1.1 vs. 1.3±0.9, p=0.003 and distal reference: 1.7±1.1 vs. 1.1±1.1, p=0.003, respectively). CONCLUSIONS VV neovascularization of coronary arteries was more enhanced in patients with ACS than in those with SAP, supporting its relation to plaque vulnerability. VV detected by widely used IVUS could be an adequate surrogate marker for plaque vulnerability in vivo.