Junko Honye

Morphological effects of coronary balloon angioplasty in vivo assessed by intravascular ultrasound imaging.

BACKGROUND Histological examination of the effects of balloon angioplasty have been described from in vitro experiments and a limited number of pathologic specimens. Intravascular ultrasound imaging permits real time cross-sectional observation of the effect of balloon dilation on the atherosclerotic plaque in vivo. METHODS AND RESULTS The morphological effects of coronary angioplasty were visualized at 66 lesions in 47 patients immediately after balloon dilatation with an intravascular ultrasound imaging catheter. Cross-sectional images were obtained at 30 frames per second as the catheter passed along the length of the artery. Quantitative and qualitative assessments of the dilated atherosclerotic plaque were made from the angiograms and the ultrasound images. Six morphological patterns after angioplasty were appreciated by ultrasound imaging. Type A consists of a linear, partial tear of the plaque from the lumen toward the media (seven lesions); Type B is defined by a split in the plaque that extends to the media (12 lesions); Type C demonstrates a dissection behind the plaque that subtends an arc of up to 180 degrees around the circumference (18 lesions); Type D was a more extensive dissection that encompasses an arc of more than 180 degrees (four lesions); and Type E may be present in either concentric (Type E1, 14 lesions) or eccentric (Type E2, 11 lesions) plaque and is defined as an ultrasound study without any evidence of a fracture or a dissection in the plaque. There was a large amount of residual atheroma in each type of morphology (7.8 +/- 2.9 mm2, 61.6 +/- 15.4% of cross-sectional area); there was no difference, however, in lumen or atheroma cross-sectional area among these six patterns. There was a good correlation between ultrasound and angiography for the recognition of a dissection. Calcification was seen in only 14% of lesions on angiography, whereas most lesions (83%) revealed calcification on ultrasound imaging. As determined by intravascular ultrasound, calcified plaque was more likely to fracture in response to balloon dilatation than noncalcified plaque (p less than 0.01). Thirteen of 66 lesions (20%) developed clinical and angiographic restenosis. Restenosis was more likely to occur when the original dilatation left a concentric plaque without a fracture or dissection (Type E1, 50% incidence) compared with a mean restenosis rate of 12% in the remaining morphological patterns (p = 0.053). CONCLUSIONS Intravascular ultrasound provides a more complete quantitative and qualitative description of plaque geometry and composition than angiography after balloon angioplasty. In addition, intravascular ultrasound identified a subset of atherosclerotic plaque that has a higher incidence of restenosis. This information could be used prospectively to consider other therapeutic options in this subset. Intravascular ultrasound provides a method to describe the effects of angioplasty that will be useful in comparing future coronary intervention studies.

Prediction of Progression of Coronary Artery Disease and Clinical Outcomes Using Vascular Profiling of Endothelial Shear Stress and Arterial Plaque Characteristics: The PREDICTION Study

Background— Atherosclerotic plaques progress in a highly individual manner. The purposes of the Prediction of Progression of Coronary Artery Disease and Clinical Outcome Using Vascular Profiling of Shear Stress and Wall Morphology (PREDICTION) Study were to determine the role of local hemodynamic and vascular characteristics in coronary plaque progression and to relate plaque changes to clinical events. Methods and Results— Vascular profiling, using coronary angiography and intravascular ultrasound, was used to reconstruct each artery and calculate endothelial shear stress and plaque/remodeling characteristics in vivo. Three-vessel vascular profiling (2.7 arteries per patient) was performed at baseline in 506 patients with an acute coronary syndrome treated with a percutaneous coronary intervention and in a subset of 374 (74%) consecutive patients 6 to 10 months later to assess plaque natural history. Each reconstructed artery was divided into sequential 3-mm segments for serial analysis. One-year clinical follow-up was completed in 99.2%. Symptomatic clinical events were infrequent: only 1 (0.2%) cardiac death; 4 (0.8%) patients with new acute coronary syndrome in nonstented segments; and 15 (3.0%) patients hospitalized for stable angina. Increase in plaque area (primary end point) was predicted by baseline large plaque burden; decrease in lumen area (secondary end point) was independently predicted by baseline large plaque burden and low endothelial shear stress. Large plaque size and low endothelial shear stress independently predicted the exploratory end points of increased plaque burden and worsening of clinically relevant luminal obstructions treated with a percutaneous coronary intervention at follow-up. The combination of independent baseline predictors had a 41% positive and 92% negative predictive value to predict progression of an obstruction treated with a percutaneous coronary intervention. Conclusions— Large plaque burden and low local endothelial shear stress provide independent and additive prediction to identify plaques that develop progressive enlargement and lumen narrowing. Clinical Trial Registration— URL: http:www.//clinicaltrials.gov. Unique Identifier: NCT01316159.

Effect of fluvastatin on progression of coronary atherosclerotic plaque evaluated by virtual histology intravascular ultrasound.

OBJECTIVES The aim of this study was to evaluate the effect of treatment with statins on the progression of coronary atherosclerotic plaques of a nonculprit vessel by serial volumetric virtual histology (VH) intravascular ultrasound (IVUS). BACKGROUND Recent clinical trials have demonstrated a reduction of atherosclerotic plaque, yet whether statin therapy affects the change in components of plaque remains unknown. METHODS This study was a nonrandomized and nonblinded design. Eighty patients with stable angina pectoris were divided into either the fluvastatin group (n = 40) or the control group (n = 40) according to their total or low-density lipoprotein (LDL) cholesterol level. The volume of each plaque component (dense calcium, fibrous tissue, fibro-fatty, or necrotic core) was evaluated at baseline and at 12-month follow-up. RESULTS The LDL cholesterol and high-sensitivity C-reactive protein (hsCRP) levels in the fluvastatin group were significantly decreased at time of follow-up. In VH IVUS findings, fibro-fatty volume was significantly decreased (baseline 80.1 +/- 57.9 mm(3) vs. follow-up 32.5 +/- 27.7 mm(3), p < 0.0001) and fibrous tissue volume was increased (baseline 146.5 +/- 85.6 mm(3) vs. follow-up 163.3 +/- 94.5 mm(3), p < 0.0001) in the fluvastatin group. In the control group, the volumes of all plaque components without fibrous tissue were significantly increased. Change in fibro-fatty volume has a significant correlation with a change in LDL cholesterol level (R = 0.703, p < 0.0001) and change in hsCRP level (R = 0.357, p = 0.006). CONCLUSIONS One-year lipid-lowering therapy by fluvastatin showed significant regression of plaque volume and alterations in atherosclerotic plaque composition with a significant reduction of fibro-fatty volume.

Antiischemic effects of nicorandil during coronary angioplasty in humans

SummaryThe present study was undertaken on 10 patients with angina undergoing percutaneous transluminal coronary angioplasty. The angioplasty procedure consisted of two successive 30-second balloon inflations at 5 minute intervals. After the first inflation, nicorandil (0.1 mg/kg) was given intravenously over a 2-minute period. The second inflation was then performed 3 minutes after the completion of drug administration. Myocardial ischemia was measured as the magnitude of ST-segment elevation on the intracoronary electrocardiogram (intracoronary ECG) recorded from the guidewire. Nicorandil significantly reduced the magnitude of ST-segment elevation. Nicorandil did not change the heart rate-blood pressure product, nor the oxygen saturation of the blood sampled from the great cardiac vein, nor the velocity of coronary blood flow in those patients with no evidence of collaterals. These results favor the conclusion that nicorandil prolongs the intrinsic ability of cardiac myocyte to withstand oxygen deprivation. This salutary effect is possibly due to a direct cellular mechanism because nicorandil did not modify the peripheral and coronary hemodynamic parameters that govern myocardial oxygen consumption.

Coronary Disease Morphology and Distribution Determined by Quantitative Angiography and Intravascular Ultrasound

Although previous studies have demonstrated that even quantitative coronary angiography (QCA) can not provide accurate disease morphology, there has not been a systematic comparison of disease morphology determined by QCA and intravascular ultrasound (IVUS), particularly in Japanese patients. Therefore, the present study prospectively examined patients in a multicenter cooperative study. A total of 491 coronary sites from 562 patients (446 men, 116 women; mean age, 64+/-11 years) who underwent coronary interventions were enrolled. The target lesions (>50% diameter stenosis) were evaluated pre-operatively by both QCA and IVUS operating at 30-40 MHz and the percent area stenosis, eccentricity index (EI) and lesion length were determined. The minimal (min) and maximal (max) distances from the center of the stenotic lesion to the outline of the vessel wall were measured, and the EI was calculated by the formula: [(max - min)/max]. By QCA, lesion length was determined by measuring the distance between the proximal and distal shoulders of the lesion. When the lesions were observed by IVUS with a motorized pull-back system, the length was calculated by multiplying the time for observation of the disease and 0.5 or 1 mm/s. Although the severity of the stenosis determined by QCA (86+/-10%, mean +/- SD) did not differ from that by IVUS (83+/-13%), there was no correlation between them (r=0.32, y=0.25x+65) and the correlation did not improve when lesions with remodeling, enlargement (n=176) or shrinkage (n=79) were omitted from the calculation. The EIs by QCA and IVUS were 0.51+/-0.26 and 0.52+/-0.22, respectively (NS), and there was no correlation between them (r=0.30, y=0.36x+33). However, when the lesions with remodeling were excluded, the correlation greatly improved (r=0.80, y=0.84x+10.6, p<0.05). Lesion length determined by QCA (12.4+/-6.1 mm) was significantly shorter than that by IVUS (16.3+/-8.9 mm, p<0.01). These results demonstrate that coronary angiography significantly misinterprets disease morphology in terms of severity, eccentricity and length, in part because of vessel remodeling that can be accurately determined only by IVUS.

SCAI consensus document on occupational radiation exposure to the pregnant cardiologist and technical personnel

Concerns regarding radiation exposure and its effects during pregnancy are often quoted as an important barrier preventing many women from pursuing a career in Interventional Cardiology. Finding the true risk of radiation exposure from performing cardiac catheterization procedures can be challenging and guidelines for pregnancy exposure have been inadequate. The Women in Innovations group of Cardiologists with endorsement of the Society for Cardiovascular Angiography and Interventions aim to provide guidance in this publication by describing the risk of radiation exposure to pregnant physicians and cardiac catheterization personnel, to educate on appropriate radiation monitoring and to encourage mechanisms to reduce radiation exposure. Current data do not suggest a significant increased risk to the fetus of pregnant women in the cardiac catheterization laboratory and thus do not justify precluding pregnant physicians from performing procedures in the cardiac catheterization laboratory. However, radiation exposure among pregnant physicians should be properly monitored and adequate radiation safety measures are still warranted.

Plaque Morphology at Coronary Sites With Focal Spasm in Variant Angina

In the present study, the intravascular ultrasound (IVUS) morphologic appearance of coronary atherosclerotic plaque associated with focal spasm was prospectively studied in 45 patients with or without focal coronary spasm provoked by ergonovine or acetylcholine. The percent plaque area and plaque arc were determined from the IVUS images at the sites of spasm. Calcified lesion was defined as the presence of high-intensity echo with acoustic shadowing. Twenty-three patients had focal coronary spasm defined as angiographic narrowing >75% and IVUS demonstrated atherosclerotic plaque in these 23 sites. In the 22 patients without focal spasm, IVUS demonstrated 18 atherosclerotic lesions in 17 patients and the remaining 5 patients did not have significant lesions. There was no difference in the percent plaque area and plaque arc between plaque lesions with (47+/-10%, 298+/-71 degrees ) and without (39+/-15%, 249+/-83 degrees ) coronary spasm. Interestingly, calcified lesion was less frequently present at the sites with than at those without spasm (p<0.05). These results indicate that the presence of plaque without calcification is likely to be related to the occurrence of focal vasospasm, although the severity and distribution of the disease did not differ between each patient group.

Intravascular ultrasound imaging following balloon angioplasty

Despite its long history and reliability, contrast angiography has several inherent limitations. Because it is a two-dimensional projection image of the lumen contour, the wall thickness cannot be measured and the plaque itself is not visualized. This results in an underestimation of the amount of atherosclerotic disease by angiography. An assessment of atherosclerosis could be improved by an imaging modality: (1) that has an inherent larger magnification than angiography and (2) that directly visualizes the plaque. Intravascular ultrasound fulfils these criteria. This presentation will provide evidence that intravascular ultrasound may prove complimentary or even superior to angiography as an imaging modality.Intravascular ultrasound demonstrates excellent representations of lumen and plaque morphology ofin vitro specimens compared with histology. There is very close intraobserver and interobserver variability of measurements made from intravascular ultrasound images. Phantom studies of stenoses in a tube model demonstrate that angiography can misrepresent the severity of stenosis when the lumen contour is irregular and not a typical ellipse, whereas intravascular ultrasound reproduces the cross-sectional morphology more accurately since it images the artery from within.In vitro studies of the atherosclerotic plaque tissue characteristics compare closely with the echo representation of fibrosis, calcification, and lipid material. In addition,in vitro studies of balloon angioplasty demonstrate that intravascular ultrasound accurately represents the changes in the structure of artery segments following balloon dilatation.

Plaque stabilization by intensive LDL-cholesterol lowering therapy with atorvastatin is delayed in type 2 diabetic patients with coronary artery disease—Serial angioscopic and intravascular ultrasound analysis

BACKGROUND Diabetes mellitus (DM) is a major risk factor for cardiovascular events. The study purpose was to compare DM and non-DM (nDM) patients in terms of statin-induced change of plaque characteristics using intravascular ultrasound (IVUS) and coronary angioscopy. METHODS Patients with coronary artery disease and hypercholesterolemia who were enrolled to the TWINS were selected and classified into two groups: DM group and nDM group. Eleven DM patients and 28 nDM patients were studied. RESULTS Low-density lipoprotein cholesterol levels decreased significantly to a similar extent at weeks 28 and 80 from baseline in DM and nDM (p<0.001). The mean angioscopic color grades of yellow plaques in DM and nDM were similar at baseline and significantly decreased at week 80 from baseline in both groups, however, the mean change of angioscopic color grade from baseline in DM were not significantly decreased and the mean angioscopic color was significantly higher than that in nDM (1.34 vs. 1.00, p<0.05) at week 28. IVUS showed plaque volume reduction in both groups (p<0.01) except at week 80 in DM group, which was not statistically significant different compared to the baseline. CONCLUSION In DM patients, plaque volume regression by atorvastatin was shown to be attenuated, and its color improvement was significantly delayed. However, the yellowness became comparable between DM and nDM groups at week 80. These results indicate that patients with DM should be treated by intensive lipid-lowering therapy with atorvastatin for at least 80 weeks to stabilize vulnerable plaque.

SCAI consensus document on occupational radiation exposure to the pregnant cardiologist and technical personnel.

Concerns regarding radiation exposure and its effects during pregnancy are often quoted as an important barrier preventing many women from pursuing a career in Interventional Cardiology. Finding the true risk of radiation exposure from performing cardiac catheterisation procedures can be challenging and guidelines for pregnancy exposure have been inadequate. The Women in Innovations group of Cardiologists with endorsement of the Society for Cardiovascular Angiography and Interventions aim to provide guidance in this publication by describing the risk of radiation exposure to pregnant physicians and cardiac catheterisation personnel, to educate on appropriate radiation monitoring and to encourage mechanisms to reduce radiation exposure. Current data do not suggest a significant increased risk to the fetus of pregnant women in the cardiac catheterisation laboratory and thus do not justify precluding pregnant physicians from performing procedures in the cardiac catheterisation laboratory. However, radiation exposure among pregnant physicians should be properly monitored and adequate radiation safety measures are still warranted.