Yasuto Uchida

Detection of Vulnerable Coronary Plaques by Color Fluorescent Angioscopy

OBJECTIVES This study was carried out to detect vulnerable coronary plaques by color fluorescent angioscopy. BACKGROUND Collagen fibers (CFs) mainly provide mechanical support to coronary plaques. Oxidized low-density lipoprotein (Ox-LDL) induces macrophage proliferation, which in turn destroy CFs while accumulating lipids. As such, demonstration of the absence of CFs, deposition of lipids, and the Ox-LDL may suggest plaque instability. METHODS Fluorescence of the major components of the atherosclerotic plaques was examined by fluorescent microscopy using a 345-nm band-pass filter and 420-nm band-absorption filter (A-imaging). Fluorescence of Ox-LDL was examined using a 470-nm band-pass filter and 515-nm band-absorption filter (B-imaging) and Evans blue dye as an indicator. Fluorescence in 57 excised human coronary plaques was examined by A-imaging color fluorescent angioscopy. Oxidized LDL in 31 excised coronary plaques and in 12 plaques of 7 patients was investigated by B-imaging color fluorescent angioscopy. RESULTS Collagen I, collagen IV, and calcium exhibited blue, light blue, and white autofluorescence, respectively. In the presence of beta-carotene which coexists with lipids in the vascular wall, collagen I and IV exhibited green, collagen III and V white, cholesterol yellow, cholesteryl esters orange fluorescence. Oxidized LDL exhibited reddish brown fluorescence in the presence of Evans blue dye. Therefore, coronary plaques exhibited blue, green, white-to-light blue, or yellow-to-orange fluorescence based on plaque composition. Histological examination revealed abundant CFs without lipids in blue plaques; CFs and lipids in green plaques; meager CFs and abundant lipids in white-to-light blue plaques; and the absence of CFs and deposition of lipids, calcium, and macrophage foam cells in the thin fibrous cap in yellow-to-orange plaques, indicating that the yellow-to-orange plaques were most vulnerable. Reddish brown fluorescence characteristic of Ox-LDL was observed in excised coronary plaques, as also in patients. CONCLUSIONS Color fluorescent angioscopy provides objective information related to coronary plaque composition and may help identify unstable plaques.

Possible Participation of Endothelial Cell Apoptosis of Coronary Microvessels in the Genesis of Takotsubo Cardiomyopathy

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.

Localization of Oxidized Low-Density Lipoprotein and Its Relation to Plaque Morphology in Human Coronary Artery

Objectives Oxidized low-density lipoprotein (oxLDL) plays a key role in the formation of atherosclerotic plaques. However, its localization in human coronary arterial wall is not well understood. The present study was performed to visualize deposition sites and patterns of native oxLDL and their relation to plaque morphology in human coronary artery. Methods Evans blue dye (EB) elicits a violet fluorescence by excitation at 345-nm and emission at 420-nm, and a reddish-brown fluorescence by excitation at 470-nm and emission at 515-nm characteristic of oxLDL only. Therefore, native oxLDL in excised human coronary artery were investigated by color fluorescent microscopy (CFM) using EB as a biomarker. Results (1) By luminal surface scan with CFM, the % incidence of oxLDL in 38 normal segments, 41 white plaques and 32 yellow plaques that were classified by conventional angioscopy, was respectively 26, 44 and 94, indicating significantly (p<0.05) higher incidence in the latter than the former two groups. Distribution pattern was classified as patchy, diffuse and web-like. Web-like pattern was observed only in yellow plaques with necrotic core. (2) By transected surface scan, oxLDL deposited within superficial layer in normal segments and diffusely within both superficial and deep layers in white and yellow plaques. In yellow plaques with necrotic core, oxLDL deposited not only in the marginal zone of the necrotic core but also in the fibrous cap. Conclusion Taken into consideration of the well-known process of coronary plaque growth, the results suggest that oxLDL begins to deposit in human coronary artery wall before plaque formation and increasingly deposits with plaque growth, exhibiting different deposition sites and patterns depending on morphological changes.

Molecular Imaging of Low-density Lipoprotein in Human Coronary Plaques by Color Fluorescent Angioscopy and Microscopy

Objectives Low-density lipoprotein (LDL) is an important risk factor for coronary artery disease. However, its localization in human coronary plaques is not well understood. The present study was performed to visualize LDL in human coronary artery wall. Methods (1) The fluorescence characteristic of LDL was investigated by color fluorescent microscopy (CFM) with excitation at 470-nm and emission at 515-nm using Nile blue dye (NB) as a biomarker. (2) Native LDL in 40 normal segments, 42 white plaques and 35 yellow plaques (20 with necrotic core) of human coronary arteries was investigated by color fluorescent angioscopy (CFA) and CFM. Results (1) NB elicited a brown, golden and red fluorescence characteristic of LDL, apolipoprotein B-100, and lysophosphatidylcholine/triglyceride, respectively. (2) The % incidence of LDL in normal segments, white, and yellow plaques was 25, 38 and 14 by CFA and 42, 42 and 14 by CFM scan of their luminal surface, respectively, indicating lower incidence (p<0.05) of LDL in yellow plaques than white plaques, and no significant differences in detection sensitivity between CFA and CFM. By CFM transected surface scan, LDL deposited more frequently and more diffusely in white plaques and yellow plaques without necrotic core (NC) than normal segments and yellow plaques with NC. LDL was localized to fibrous cap in yellow plaques with NC. Co-deposition of LDL with other lipid components was observed frequently in white plaques and yellow plaques without NC. Conclusions (1) Taken into consideration of the well-known process of coronary plaque growth, the results of the present study suggest that LDL begins to deposit before plaque formation; increasingly deposits with plaque growth, often co-depositing with other lipid components; and disappears after necrotic core formation. (2) CFA is feasible for visualization of LDL in human coronary artery wall.

Two-Dimensional Visualization of Cholesterol and Cholesteryl Esters Within Human Coronary Plaques by Near-Infrared Fluorescence Angioscopy

Cholesterol (C) and cholesteryl esters (CE) within coronary plaques are minimally visualized directly by any of the available imaging modalities in vivo. If they are rendered visible in vivo, the progression of coronary plaques and the effects of respective therapies on these plaques can be objectively evaluated.

Short- and Long-Term Follow-up of Percutaneous Coronary Intervention for Chronic Total Occlusion through Transradial Approach: Tips for Successful Procedure from a Single-Center Experience

BACKGROUND  There are limited data regarding transradial percutaneous coronary intervention (PCI) for chronic total occlusion (CTO). OBJECTIVE  To assess the feasibility and safety of transradial coronary intervention (TRI) for CTO lesions, we analyzed our experience in PCI treatment of CTO lesion through transradial approach for the past 6 years. METHODS  From January 2003 to May 2009, among 134 CTO lesions, on which we performed PCI, 120 lesions were performed from transradial approach. RESULTS  Technical success for transradial CTO was 80%. Complication of access bleeding was zero. The most commonly selected guiding wire was Wave 3 for right coronary artery (RCA) lesions (82%) and Voda left for Left Coronary Artery (LCA) lesions (91%). The average number of wires used during procedure was 2.2 ± 0.8. Tapered wire was used in 8% of the cases, Rotablator was performed in 4.1% of cases, and Tornus catheter was performed in 12.5% of cases. The mean procedure time was 83 ± 39 minutes. The mean volume of contrast medium used was 228 ± 92 mL. There were two coronary artery perforations during procedure and one in-hospital cardiac death. Patients were followed up for 36 ± 21 months; restenosis rate was 19.5%-26.7% for bare metal stent (BMS) and 9.8% for drug-eluting stents (DES). Overall major adverse cardiac events (MACE) rate was 11.7%. CONCLUSION  It was demonstrated that transradial PCI for CTO lesions is safe, minimizing vascular complications without increasing procedural time and contrast use.

Scintigraphic studies on the etiology of Ampulla Cardiomyopathy

BACKGROUND Although there are many reports on Ampulla Cardiomyopathy, its etiologic mechanisms are not well known. AIM Etiology of Ampulla Cardiomyopathy was investigated by myocardial scintigraphy with various nuclear tracers. SUBJECTS AND METHODS In nine patients with Ampulla Cardiomyopathy, myocardial scintigraphy was performed at acute, subacute and chronic phases. Total defect score (TDS) of tallium-201 (Tl) or technetrium-99m sestamibi (MIBI) myocardial perfusion and iodine-123-beta-methyl-p-iodophenyl penta-decanoic acid (BMIPP) scintigraphies was calculated. Cardio-mediastinal ratio (H/M) and washout rate (WR) of early and delayed images of iodine-123-meta-iodobenzylguanidine (MIBG) scintigraphy were also calculated. The patients in whom TDS of myocardial perfusion scintigraphy at acute phase was 0, were classified into group N (n = 5) and those with TDS > or = 1 into group D (n = 4). RESULTS TDS of BMIPP at acute, subacute and chronic phases was higher in D than in N; 28.8 +/- 10.3 vs. 7.2 4.7 (p = 0.0039), 15.5 +/- 2.1 vs. 1.0 +/- 0.8 (p < 0.0001) and 2.7 +/- 1.2 vs. 0 (p = 0.05), respectively. WR of MIBG at acute phase was also higher in D (50.3 +/- 5.7% vs. 36.6 +/- 10.5%, p = 0.05). H/M (dH/M) on the delayed images and WR at chronic phase were not different between the two groups. H/M (eH/M) on the early images was lower in D. Blood noradrenaLine (ng/ml) at acute phase was higher in D than in N (1.21 +/- 0.55 vs. 0.45 +/- 0.33, p < 0.05). Left ventricular ejection fraction (LVEF) was decreased in both at acute phase but it was lower in D than in N (48.1 +/- 3.7% vs. 69.9 +/- 9.7%, p < 0.05) at subacute phase. CONCLUSION These findings suggest that the etiology of Ampulla Cardiomyopathy is neurologically stunned myocardium induced by coronary microcirculatory disorder. Due to the significant amount of time that was necessary for normalization of wall motion in the D group, myocardial scintigraphy is believed to be also useful in assessment of severity.

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

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.

Treatment of non-left main bifurcation lesions using the sirolimus-eluting stent: A comparison of chronic outcomes of cross-over single stenting and crush stenting

BACKGROUND It is said that the chronic outcomes of the two-stent technique for bifurcation lesions are inferior to that of cross-over single stenting. However, there are many cases where true bifurcations are difficult to treat by single stenting and, in particular, strategies for bifurcation lesions that are not left main trunk (LMT) bifurcations are still not clear. OBJECTIVE This study aims to compare the usefulness of crush stenting with that of cross-over single stenting using the sirolimus-eluting stent (SES) on bifurcation lesions with the exclusion of LMT bifurcations. METHODS Subjects were 92 consecutive patients (100 lesions) who underwent cross-over single stenting or crush stenting using SES for bifurcation lesions with the exclusion of LMT bifurcations. The patients were divided into 33 patients with 34 lesions, in whom the stent was implanted in the main vessel alone with the kissing balloon technique performed for the main vessel and side branch (Single-stenting group; S group), and 59 patients with 66 lesions, in whom the stent was implanted through crush stenting (Crush-stenting group; C group). The two groups were compared for target lesion revascularization (TLR) and major adverse cardiac events (MACE). RESULTS There were no differences for TLR, with this conducted in the main vessel in 5.9% of S group and 4.5% of C group. There was no difference between the groups in MACE with 9.1% in S group and 8.5% in C group. No significant difference was seen in MACE-free survival rate in the chronic phase with 93.9% for S group and 94.9% for C group (P=NS). CONCLUSION No differences in chronic clinical outcomes were revealed in a comparison between cross-over single stenting and crush stenting. Good clinical outcomes were achieved by both cross-over single stenting and crush stenting in the treatment of non-left main bifurcation lesions.