Detection of Ceramide, a Risk Factor for Coronary Artery Disease, in Human Coronary Plaques by Fluorescent Angioscopy.

BACKGROUND: The presence of ceramide in human coronary plaques is a risk factor for ischemic heart disease, but its visualization in the human vessel wall is currently beyond the scope of any available imaging techniques.Methods and Results:Deposition of ceramide was examined by fluorescent angioscopy (FA) and microscopy (FM) using golden fluorescence (Go) as a specific marker of ceramide in yellow plaques, which were obtained from 23 autopsy subjects and classified by conventional angioscopy and histology. Ceramide was observed by FM in 34 of the 41 yellow plaques with a necrotic core (NC) but rarely in the 28 without. Ceramide and macrophages/foam cells co-deposited mainly in the border zone of the NC and fibrous cap (FC). The Go of ceramide was seen when the fibrous cap thickness was ≤100 µm. FA was performed to detect coronary plaques exhibiting Go in patients with coronary artery disease. Ceramide was also detected by FA in 6 of 18 yellow plaques (33.3%) in 8 patients with stable angina and in 18 of 24 yellow plaques (75.0%, P<0.05 vs. stable angina) in 8 patients with old myocardial infarction. CONCLUSIONS: The Go of ceramide in human coronary plaques is detectable by FA and Go could be used as a marker of vulnerable plaque (i.e., thin FC with NC).

Characterization of coronary fibrin thrombus in patients with acute coronary syndrome using dye-staining angioscopy.

OBJECTIVE: Because fibrin is transparent and almost invisible by any conventional imaging methodologies, clinical examinations of coronary fibrin thrombus have been ignored, and little is known about its role in the genesis of acute coronary syndrome (ACS). The present study was performed to visualize coronary fibrin thrombus and to examine its role in ACS. METHODS AND RESULTS: Dye-staining coronary angioscopy using Evans blue dye, which selectively stains fibrin blue but does not stain blood corpuscles, was performed for observation of globular coronary thrombi in 111 ACS patients. The thrombi were aspirated for histological examination. The thrombi were classified by visual appearance into 8 transparent, 3 light-red, 2 frosty glass-like and membranous, 32 white, 8 brown, 34 red, and 19 red-and-white in a mosaic pattern. Transparent thrombi that were not visible by conventional angioscopy were visualized as a blue structure by dye-staining angioscopy, and they were observed in patients with unstable angina (UA) and non-ST elevation myocardial infarction (NSTEMI). The thrombi caused total or subtotal coronary occlusion. The aspirated thrombi were composed of fibrin alone by histology. Fibrin-rich thrombi were visualized using dye-staining angioscopy in 60% of 50 patients with UA+NSTEMI and in 29% of 61 patients with ST-elevation myocardial infarction. By histology of the aspirated thrombi, fibrin-rich thrombi were observed in 71% of 33 patients with UA+NSTEMI and in 28% of 35 patients with ST-elevation myocardial infarction. CONCLUSION: Fibrin-rich coronary thrombi were frequently observed by both dye-staining angioscopy and histology in ACS patients. Rarely, fibrin itself formed a globular thrombus and caused coronary occlusion.

Cardioscopic detection of left ventricular thrombi. -With special reference to a comparison with left ventriculography and echocardiography-.

BACKGROUND: Thrombosis occurs in the left ventricle and causes ischemic cerebral attacks. However, differences in the incidence of left ventricular thrombi (LVT) among various categories of heart diseases are not known. METHODS AND RESULTS: From April 2000 to 31 March 2008, 258 patients (104 females and 154 males; age 63 ± 6 years) with a heart disease underwent cardioscopy of the left ventricle. LVT were detected by cardioscopy in 78 of 258 patients; 12.5% of 57 patients with stable angina, 0% of 9 with unstable angina, 45.2% of 42 with acute myocardial infarction, 23.2% of 43 with old myocardial infarction, 61.9% of 21 with idiopathic acute myocarditis, 44.3% of 68 with idiopathic chronic myocarditis, 33.3% of 6 with rheumatic valvular disease, 25.7% of 31 with idiopathic dilated cardiomyopathy and in 8.0% of 12 with idiopathic hypertrophic cardiomyopathy. Nine of 78 thrombi were globular and 69 were mural. The detection rate of LVT by cardioscopy, left venticulography, non-contrast and contrast echocardiography was 30.2%, 2.7%, 1.9% and 7.0%, respectively. CONCLUSIONS: LVT were frequently detected by cardioscopy in patients with heart diseases. Although invasive, cardioscopy was more sensitive in detecting LVT than left ventriculography, and non-contrast and contrast echocardiography.

Cardioscopic observation of subendocardial microvessels in patients with coronary artery disease.

Coronary microvessels play a direct and critical role in determining the extent and severity of myocardial ischemia and cardiac function. However, because direct observation has never been performed in vivo, the functional properties of the individual microvesssels in patients with coronary artery disease remain unknown. Subendocardial coronary microvessels were observed by cardioscopy in 149 successive patients with coronary artery disease (81 with stable angina and 68 with old myocardial infarction). Twenty-four arterial microvessels (AMs) and 27 venous microvessels (VMs) were observed in the left ventricular subendocardium. All 12 AMs and 13 of 14 VMs that were located in normokinetic-to-hypokinetic left ventricular wall segments were filled with blood during diastole and were collapsed during systole. In contrast, 8 of 12 AMs and 9 of 13 VMs that were located in akinetic-to-dyskinetic wall segments were filled with blood during systole and were collapsed during diastole. There were no significant correlations between the timing of blood filling and the severity of coronary stenosis and collateral development. In patients with coronary artery disease, the timing of blood filling of AMs and VMs was dependent on the regional left ventricular contractile state; during diastole when contraction was preserved and during systole when it was not. It remains to be elucidated whether and how blood filling is disturbed in other categories of heart disease.

Possible role of damaged neoendothelial cells in the genesis of coronary stent thrombus in chronic phase. A dye staining angioscopic study.

The mechanism(s) underlying formation of coronary stent thrombus (ST) in chronic phase is yet unclear. Endothelial cells are highly antithrombotic, therefore, it is conceivable that neoendothelial cells (NECs) covering stent struts are damaged and cause ST. This study was performed to examine the role of damaged NECs covering coronary stent struts in the genesis of occlusive or nonocclusive ST in chronic phase.(1) Forty-four patients with acute coronary syndrome (17 females and 27 males) underwent dye-staining coronary angioscopy, using Evans blue which selectively stains damaged endothelial cells, 6 months after bare-metal stent (BMS) deployment. Neointimal coverage was classified into not covered (grade 0), covered by a thin layer (grade 1), and buried under neointima (grade 2) groups. (2) In 7 beagles, the relationships between neointimal thickness and ST were examined 6 months after BMS deployment. (3) The NECs on the struts were stained blue in 4 of 25 patients with grade 2 and in 11 of 20 patients with grade 0/1 (P < 0.05). ST was observed in none of the former and in 5 of the latter (P < 0.05). (4) In beagles, neointimal coverage was grade 0/1 when neointimal thickness was 80.2 ± 40.0 µm, whereas grade 2 when thickness was 184 ± 59.4 µm. ST was observed in 9 of 15 struts with neointimal thickness within 100 µm and in one of 17 struts with thickness over 100 µm (P < 0.05). ST arose from damaged NECs covering the stent struts. NECs may have been damaged due to friction between them and struts due to thin interposed neointima which might have acted as a cushion, resulting in ST.

Nitroglycerin-induced heterogeneous subendocardial myocardial blood flow observed by cardioscopy in patients with coronary artery disease.

It is controversial as to whether or not nitroglycerin (NTG) increases subendocardial myocardial blood flow (SMBF), and if it does, whether arterial or venous blood flow is increased in patients with coronary artery disease. This study was performed to examine NTG-induced changes in SMBF.Changes in SMBF induced by NTG (200 µg, i.v.) were examined by cardioscopy in 58 left ventricular wall segments of 58 patients with coronary artery disease. NTG-induced red and purple endocardial colors were defined as increased arterial and venous SMBF, respectively. Endocardial color before NTG administration was classified into brown, light brown, pale and white. Endomyocardial biopsy of the observed portion and (201)Tl scintigraphy were performed in 40 of these patients immediately after cardioscopy and several days after cardioscopy, respectively.Upon administration of NTG, SMBF increased in 48 of 58 wall segments; arterial SMBF in 34 and venous SMBF in 12 wall segments; arterial SMBF in all 24 brown to light brown segments; venous SMBF, arterial SMBF and no change in 12, 10 and 5 of pale segments, respectively; and no change in all 10 white wall segments. (201)Tl-scintigraphy and endomyocardial biopsy revealed that brown, light brown, pale and white endocardial color represented no ischemia, mild ischemia, severe ischemia and fibrosis, respectively.NTG caused an increase in either arterial or venous SMBF depending on control endocardial color, wall motion and severity of coronary stenosis.

Role of a streamer-like coronary thrombus in the genesis of unstable angina.

INTRODUCTION: It is generally believed that the coronary occlusion occurs at the site of plaque disruption in acute coronary syndromes. An exceptional mechanism of coronary occlusion, namely a streamer-like thrombus (SLT) originating in a nonstenotic lesion extended distally to obstruct a just distal nondisrupted stenotic segment, was found by angioscopy in patients with unstable angina (UA). This study was carried out to examine the incidence of this phenomenon and its relationship to the subtypes of UA. METHODS: The culprit coronary artery was investigated by angioscopy in successive 48 patients (mean +/- SE age, 61.0 +/- 2.3 years; 10 females and 38 males) with UA. RESULTS: SLT originating in a nonstenotic lesion extended distally, and obstructed the just distal most stenotic segment (DMSS) by its tail in 11 patients (eight with class III and three with class II according to Braunwald's classification). Recurrent anginal attacks were observed in all. The nonstenotic lesion in which the SLT originated was a disrupted yellow plaque in most cases. The SLT was frequently red and yellow in a mosaic pattern, indicating a mixture of fresh thrombus and plaque debris. The plaques that constructed the DMSS were not disrupted. Angiographically, the SLT was not detectable and the entry of the DMSS showed a "tapering" configuration. CONCLUSIONS: Obstruction of the DMSS by the tail of SLT originating in a nonstenotic lesion is another mechanism of UA. Therefore, treatment of both the nonstenotic lesion and DMSS is needed to prevent recurrent thrombus formation and consequent reattacks.

Angioscopic detection of pulmonary thromboemboli: with special reference to comparison with angiography, intravascular ultrasonography, and computed tomography angiography.

INTRODUCTION: Pulmonary embolism (PE) is often fatal and its incidence is increasing worldwide. Detection of thromboemboli (TEi) is essential for a definitive diagnosis of PE. The detection of TEi using most imaging methods is low in patients clinically suspected of having PE. This study was carried out to detect TEi in the pulmonary arterial trees by angioscopy (AS); to classify TEi; and to compare the sensitivity of detection for TEi among AS, angiography (AG), intravascular ultrasonography (IVUS), and computed tomography angiography (CTA) in patients with clinically suspected PE. METHODS: After CTA, AG, and IVUS, the pulmonary arterial trees were surveyed by AS in 49 patients clinically suspected of having PE. RESULTS: TEi were found by AS, AG, IVUS, and CTA in 81.6%, 24.4%, 34.8%, and 22.5% of 49 patients, respectively. The 48 TEi classified by AS were globular (35%), mural (10%), cap-like (8%), web-like (4%), patchy (33%), and micro (18%). Cap-like, patchy, and micro-TEi were not detectable by AG, IVUS, and CTA in any subjects. TEi color was classified as red, white, yellow, and red-and-yellow in a mosaic pattern in 10%, 31%, 38%, and 18%, respectively. Red and white globular TEi were observed in acute, and red-and-yellow TEi in both acute and chronic PE patients. TEi other than globular were observed in both patient groups. CONCLUSION: Although invasive, AS is superior to AG, IVUS, and CTA for the detection of TEi, and therefore is a helpful imaging method for the definitive diagnosis of PE.

Fluffy luminal surface of the non-stenotic culprit coronary artery in patients with acute coronary syndrome: an angioscopic study.

BACKGROUND: Approximately 15% of acute coronary syndrome (ACS) cases have no significant coronary stenosis. Mechanisms underlying the attacks are, however, unknown. METHODS AND RESULTS: The clinical study had 254 patients with ACS; 38 patients (31 females and 7 males; aged 51.0 ± 8.0 years) had no significant coronary stenosis on angiography. They underwent a dye-staining angioscopy of the suspected culprit coronary artery using Evans blue, which selectively stains fibrin and damaged endothelial cells. A fluffy coronary luminal surface was observed in the suspected culprit artery in all 38 patients. The fluffy luminal surface was stained blue with Evans blue. In animal experiments involving 5 beagles, 10% hydrogen peroxide solution was injected into the iliac arteries to damage endothelial cells, which was then followed by blood reperfusion, and then the artery was examined by intravascular microscopy and histology. In the beagles, the arterial segment, where the thrombus had been formed, exhibited a fluffy luminal surface after a washout of the thrombus, and the surface was stained blue. Histologically, the fluffy surfaces were composed of damaged endothelial cells attached by multiple fibrin threads and platelets. CONCLUSIONS: It was considered that the coronary segment exhibiting a fluffy luminal surface was the culprit lesion and that the fluffy surface was caused by residual thrombi after dispersion of an occlusive thrombus, which had formed on the damaged endothelial cells.

Fluorescent angioscopic imaging of calcium phosphate tribasic: precursor of hydroxyapatite, the major calcium deposit in human coronary plaques.

Coronary calcification is a risk factor for ischemic heart disease. Hydroxyapatite that is formed by polymerization from calcium phosphate tribasic (CPT) is the major constituent of coronary calcium deposits. If CPT could be visualized, coronary calcification could be predicted and prevented. We discovered that when CPT and collagen I, the main constituent of collagen fibers, are mixed with lac dye (LD) and then exposed to fluorescent light excited at 345 ± 15 nm and emitted at 420 nm, a purple fluorescence that is characteristic of CPT only is elicited. So, we examined localization of CPT and its relation to plaque morphology by color fluorescent angioscopy (CFA) or microscopy (CFM) in 24 coronary arteries obtained from 12 autopsy subjects. By CFA, the incidence (%) of CPT as confirmed by purple fluorescence in 15 normal segments, 25 white plaques, 14 yellow plaques without necrotic core (NC) and 8 yellow plaques with NC was 20, 36, 64 and 100 (p < 0.05 vs. normal segments), respectively. By CFM, the CPT was either deposited alone amorphously or surrounded hydroxyapatite that was identified by Oil Red O, methylene blue and von Kossa's stain. The results suggested that CFA using LD is feasible for imaging CPT, that is a precursor of hydroxyapatite, in human coronary plaques, and this technique would help prediction and discovery of a preventive method of coronary calcification.

Imaging of Triglycerides in Human Coronary Plaques by Color Fluorescent Angioscopy and Microscopy.

Native triglycerides (TG) deposited in the human vascular wall is not measurable or visible in vivo to date. We discovered that by exciting fluorescence at 345 nm and emitting at 420 nm, 3-amino-4-hydroxy-5-nitrobenzene sulfonic acid monohydrate (3-ANA) elicits a brown fluorescence that is characteristic of just TG. Therefore, localization of TG in coronary plaques and normal segments that were obtained from 19 human autopsy cases was examined by color fluorescent angioscopy (CFA) and microscopy using 3-ANA as a biomarker of TG. By CFA, the percentage (%) incidence of TG in 23 normal segments, 13 white plaques without lipid deposition, 18 white plaques (growth stage) with lipid deposition, 11 yellow plaques without necrotic core (mature stage), and 12 yellow plaques with necrotic core (advanced mature stage) was 95, 92, 50, 27, and 25, respectively. By color fluorescent microscopy, TG deposited mostly in the fibrotic area of the plaques. Contrary to the general belief that TG amount increases with plaque maturation, the results indicated that TG was deposited in most of the normal coronary segments, but the amount decreased with plaque maturation. If 3-ANA becomes applicable clinically, the CFA system could be used for imaging TG within coronary plaques in patients in vivo.

Relationship between cardioscopic images and histological changes in the left ventricle of patients with idiopathic myocarditis.

AIMS: Endomyocardial biopsy is essential for definite diagnosis of idiopathic myocarditis. However, since endomyocardial biopsy is guided by fluoroscopy, whether or not the diseased myocardium is biopsied depends on chance, and this may lead to misdiagnosis. If the endocardial surface represents changes indicative of stages of myocarditis, staging of myocarditis and targeted cardioscope-guided biopsy could be used for accurate histological diagnosis. METHODS AND RESULTS: The relationship between left ventricular endocardial surface colour observed by cardioscopy and biopsy findings were examined in 78 patients with suspected idiopathic myocarditis. Of these, 59 patients were diagnosed histologically as idiopathic myocarditis. Endocardial colour was classified into red, milky white, purple, yellowish brown, or white. Biopsied specimens with red and milky white wall segments exhibited histological changes compatible with acute myocarditis; purple segments, active chronic myocarditis; and yellowish brown and white segments, inactive chronic myocarditis. The sensitivity, specificity, and predictive value of red and milky white colours for detecting acute myocarditis were 100, 100, and 100%, respectively; of purple for detecting active chronic myocarditis were 83, 92, and 78%, respectively; and yellowish brown and white for detecting inactive chronic myocarditis were 82, 74, and 53, respectively. CONCLUSION: Red and milky white endocardial surface colours predicted histological acute myocarditis, and purple predicted active chronic myocarditis. However, yellowish brown and white colours did not predict inactive chronic myocarditis.

Possible participation of endothelial cell apoptosis of coronary microvessels in the genesis of Takotsubo cardiomyopathy.

BACKGROUND: Takotsubo cardiomyopathy (TCM) is characterized by systolic ballooning of the left ventricular apex. It is triggered by emotional or physical stress, but the exact mechanism through which stress leads to TCM is not known. HYPOTHESIS: Coronary microvessel apoptosis is the missing link between stress and TCM. METHODS: In 8 female patients with TCM, plasma catecholamines, Thrombolysis in Myocardial Infarction (TIMI) coronary flow grade and myocardial perfusion grade, and apoptosis of the coronary microvessels in the biopsied myocardial specimen by terminal deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL) were examined. RESULTS: Plasma epinephrine and norepinephrine were increased to 663 +/- 445 and 875 +/- 812 pg/mL (mean +/- SD), respectively. Acetylcholine-induced delayed myocardial perfusion through the ballooning apical segment without flow disturbance in the epicardial coronary arteries (indicating microvessel spasm) and focal myocardial necrosis were observed in all subjects. Apical ballooning disappeared and myocardial perfusion delay was not inducible 1 month later. The number of vessels having apoptotic endothelial cells/10 vessels in arterioles, venules, and capillaries at initial biopsy and repeat biopsy 1 month later were 8.3 +/- 1.4 vs 0.4 +/- 1.1, P < 0.0001; 6.8 +/- 1.8 vs 0.3 +/- 0.7, P < 0.0001; and 7.9 +/- 1.0 vs 0.5 +/- 0.9, P < 0.0001, respectively. CONCLUSIONS: Left ventricular apical ballooning in TCM was considered to be caused by coronary microvessel spasm due to catecholamine-induced endothelial cell apoptosis and myocardial stunning after release of microvessel spasm. Endothelial cell apoptosis of coronary microvessel is therefore considered to be the missing link between stress and TCM.