Norihiko Morita

Noninvasive quantitative tissue characterization and two-dimensional color-coded map of human atherosclerotic lesions using ultrasound Integrated backscatter comparison between histology and Integrated backscatter images

OBJECTIVES The purpose of the present study was to define clinicopathologically whether integrated backscatter (IB) combined with conventional two-dimensional echo (2DE) can differentiate the tissue characteristics of calcification (CL), fibrosis (FI), lipid pool (LP) with fibrous cap, intimal hyperplasia (IH) and thrombus (TH) and can construct two-dimensional tissue plaque structure in vivo. BACKGROUND It is difficult to characterize the components of plaque using conventional 2DE techniques. METHODS Integrated backscatter values of plaques were measured in the right common carotid and femoral arteries (total 24 segments) both during life and after autopsy in 12 patients (age 68 to 84 years, 10 men and two women). Integrated backscatter values were determined using a 5-12 MHz multifrequency transducer, setting the region of interests (ROIs) (11 x 11 pixels) on the echo tomography of the entire arterial wall (55 +/- 10 ROI/segment) and comparing it with histologic features in the autopsied arterial specimens. RESULTS Corrected IB values obtained before death and at autopsy were significantly correlated (r = 0.93, p < 0.01). Corresponding to the histologic features, corrected IB values on the rectangle ROIs obtained during life were divided into five categories: category 1 (TH) 4 < IB < or = 6; category 2 (media and IH or LP in the intima) 7 < IB < or = 13; category 3 (FI) 13 < IB < or = 18, category 4 (mixed lesion) 18 < IB < or = 27 and category 5 (CL) 28 < IB < or = 33. In category 2, media and intima were differentiated using conventional 2DE. Under the above procedures, color-coded maps constructed with IB-2DE obtained during life precisely reflected the histologic features of media and intima. CONCLUSIONS Integrated backscatter with 2DE represents a useful noninvasive tool for evaluating the tissue structure of human plaque.

Considerable Time From the Onset of Plaque Rupture and/or Thrombi Until the Onset of Acute Myocardial Infarction in Humans Coronary Angiographic Findings Within 1 Week Before the Onset of Infarction

BackgroundIt has been thought that the thrombi and bleeding in plaques that occur after plaque rupture or endothelial damage from vessels with mild stenosis suddenly occlude the lumen and cause acute myocardial infarction (AMI). However, our hypothesis is that thrombi and bleeding may not suddenly occlude the lumen. Methods and ResultsThe study group consisted of 20 patients who had coronary angiograms performed within 1 week (3±3 days) before AMI and 20 control patients who had coronary angiograms performed 6 to 18 months (282±49 days) before AMI. The features of infarct-related coronary segments (IRCS) at 3 days before AMI were the presence of a significant stenosis of >50% (95% in incidence and 71±12% diameter stenosis) and Ambrose’s type II eccentric lesions (plus multiple irregularities), an indicator of plaque rupture and/or thrombi (60% [70%]), and the features at 1 year before AMI were mild stenosis of <50% (95% incidence and 30±18% diameter stenosis) with rare Ambrose’s type II eccentric lesions (plus multiple irregularities) (10% [10%]). The same relation was observed in each of the 4 subgroups with Q-wave infarction, non–Q-wave infarction, preceding effort angina within 1 month before AMI, and no preceding effort angina. ConclusionsThe appearance of marked progression and Ambrose’s type II eccentric lesion on coronary angiograms 3 days before AMI suggests the presence of a considerable time from the onset of plaque rupture and/or thrombi until the onset of AMI. These features may be predictors of AMI. The concept provides new insight into the mechanism and prevention of human AMIs.

Process of progression of coronary artery lesions from mild or moderate stenosis to moderate or severe stenosis: A study based on four serial coronary arteriograms per year.

BACKGROUND The process of progression in coronary artery disease is unknown. METHODS AND RESULTS The subjects were 36 patients with 36 objective vessels with clinically significant progression of coronary artery disease (>/=15% per year) in whom 4 serial coronary arteriograms (CAGs) were performed at intervals of approximately 4 months in a 1-year period. The degree of progression of percent stenosis between each of 2 serial CAGs was classified as marked (M: >/=15%), slight (S: 5% to 14%), and no progression (N: <5%). From the pattern of progression, the 36 vessels were classified as 14 type 1 vessels with marked progression (N-->N-->M in 13 vessels and S-->S-->M in 1 vessel) and 22 type 2 vessels without marked progression (S-->S-->S in 18 vessels, N-->S-->S in 4). Percent stenosis at the first, second, third, and final CAGs was 44+/-14%, 46+/-13%, 46+/-13%, and 88+/-10% (P<0.05 versus first CAG) in type 1 vessels and 44+/-11%, 50+/-9%, 59+/-9%, and 67+/-9% in type 2 vessels (P<0.05 for second, third, and final CAGs versus first CAG). Type 1 vessels featured the sudden appearance of severe stenosis due to marked progression, angina pectoris, or myocardial infarction (71%) and Ambrose type II eccentric lesions indicating plaque rupture or thrombi (57%). Type 2 vessels featured continuous slight progression of stenosis with smooth vessel walls; angina pectoris (14%) occurred when the percent stenosis reached a severe level. An increase in serum C-reactive protein was observed only in the type 2 vessel group, which suggests a relation between continuous slight progression and inflammatory change. CONCLUSIONS Two types of stenosis progression provide a new insight into the mechanism of coronary artery disease.

Marked expression of plasma brain natriuretic peptide is a special feature of hypertrophic obstructive cardiomyopathy

OBJECTIVES We examined whether plasma brain natriuretic peptide levels are abnormally elevated in hypertrophic obstructive cardiomyopathy compared with other cardiac diseases. BACKGROUND We previously reported that plasma brain and atrial natriuretic peptide levels were elevated in hypertrophic cardiomyopathy. METHODS We compared plasma concentrations of brain and atrial natriuretic peptide and hemodynamic and echocardiographic data in 50 patients with hypertrophic obstructive cardiomyopathy (n = 15, mean [+/-SD] intraventricular pressure gradient 37 +/- 16 mm Hg), hypertrophic nonobstructive cardiomyopathy (n = 15), aortic stenosis (n = 10, mean pressure gradient 41 +/- 18 mm Hg) and hypertensive heart disease (n = 10, mean systolic/diastolic blood pressure 203 +/- 16/108 +/- 11 mm Hg, respectively) and 10 normal subjects. RESULTS Plasma brain natriuretic peptide levels were higher in the hypertrophic obstructive cardiomyopathy group (397.1 +/- 167.8 pg/ml*) than in the hypertrophic nonobstructive cardiomyopathy (60.0 +/- 48.1 pg/ml*), hypertensive heart disease (53.9 +/- 31.4 pg/ml*), aortic stenosis (75.4 +/- 54.3 pg/ml*) and normal groups (9.8 +/- 6.4 pg/ml [*p < 0.05 vs. normal group, p < 0.05 vs. hypertrophic obstructive cardiomyopathy group]). Although plasma atrial natriuretic peptide levels were higher in the hypertrophic obstructive cardiomyopathy group than the other patient groups, the brain/atrial natriuretic peptide ratio in the hypertrophic obstructive cardiomyopathy group was higher (4.5 +/- 2.3) than those in the other three patient groups (1.1 to 1.4) and the normal group (0.7 +/- 0.5). Left ventricular end-diastolic pressure and left ventricular end-diastolic volume index were similar among the four patient groups. The interventricular septal thickness and the ratio of interventricular septal thickness to left ventricular posterior wall thickness were similar between the hypertrophic obstructive and nonobstructive cardiomyopathy groups. CONCLUSIONS Abnormal elevations of plasma brain natriuretic peptide levels are difficult to explain on the basis of hemodynamic and echocardiographic data and are a special feature of hypertrophic obstructive cardiomyopathy.

Distribution of tissue characteristics of coronary plaques evaluated by integrated backscatter intravascular ultrasound: Differences between the inner and outer vessel curvature

BACKGROUND The purpose of the present study was to evaluate the tissue characteristics of plaques with moderate or mild stenosis in the inner and outer curvature of the left anterior descending artery (LAD) using integrated backscatter intravascular ultrasound. METHODS We evaluated 66 plaques with moderate stenosis (plaque burden >50% but ≤75%) and 49 plaques with mild stenosis (plaque burden >30% but ≤50%) in 66 patients undergoing percutaneous intervention to the LAD. All plaques were >10mm away from any side branch or previously implanted stents. We divided vessel cross-sections into four quadrants (inner curvature, outer curvature, clockwise lateral side, and counterclockwise lateral side) using the septal branch as a landmark for the inner curvature. We averaged relative lipid area, relative fibrous area, and relative calcified area in minimal lumen area (MLA), three cross-sections proximal to the site of MLA, and three cross-sections distal to the site of MLA. RESULTS In plaques with moderate stenosis, the relative lipid area in the inner curvature was significantly greater than in the outer curvature and lateral sides, whereas there was no significant difference in plaques with mild stenosis. CONCLUSION The present study provides new findings that lipid pool is clustered in the inner curvature and fibrous tissue is clustered in the outer curvature of plaques with moderate stenosis in non-branching LAD lesions.

Outcomes after drug-coated balloon treatment for patients with calcified coronary lesions

OBJECTIVES To investigate the efficacy of drug-coated balloon (DCB) for calcified coronary lesions. BACKGROUND Calcified coronary lesions is associated with poor clinical outcomes after revascularization. Recently, DCB is emerging as an alternative strategy for de novo coronary lesions. However, reports describing the efficacy of DCB for calcified coronary lesions are limited. METHODS A total of 81 patients (96 lesions) who electively underwent DCB treatment for de novo coronary lesions were enrolled: 46 patients (55 lesions) in the calcified group and 35 patients (41 lesions) in the non-calcified group. Angiographic follow-up data and clinical outcomes after the procedure were evaluated. RESULTS The diameter of the DCB used was 2.5 ± 0.5 mm. No bail-out stenting was observed after DCB treatment. Rotational atherectomy was used in 82% of lesions in the calcified group. Follow-up angiography (median, 6.5 months after intervention) was performed for 59 patients (30 in the calcified group and 29 in the non-calcified group). Late lumen loss and rates of restenosis were comparable between the groups (0.03 mm in the calcified group vs -0.18 mm in the non-calcified group, P = 0.093 and 13.9% vs 3.03%, P = 0.095, respectively). The survival rates for target lesion revascularization free survival and major adverse cardiac events at 2 years were comparable between the groups (85.3% vs 93.4%, P = 0.64 and 81.4% vs 88.5%, P = 0.57, respectively). CONCLUSION Calcified coronary lesions might dilute the effect of DCB. However, clinical outcomes in the calcified group were similar to those in the non-calcified group.

Sick Sinus Syndrome After a Single Oral Administration of Garenoxacin

This report presents the case of a 60‐year‐old female who demonstrated sick sinus syndrome after a single administration of Garenoxacin (GRNX). She was administered GRNX for an upper respiratory infection and 10 minutes thereafter, she suddenly felt palpitation and numbness of both arms. She was transferred to the hospital 2 hours after taking GRNX. An electrocardiogram showed bradycardia with junctional escape beats and the longest sinus arrest was 4 seconds. She was treated with a temporary pacemaker and 21 hours after the administration of GRNX her sinus node function was observed to have completely improved. GRNX‐induced sick sinus syndrome was suspected because her clinical course was compatible with the concentration of GRNX and her other cardiological assessments, including an electrophysiologic study (EPS) which were conducted on the 9th day of the admission, were normal. GRNX has less effect on the QT interval than other quinolone agents. However, physicians should be aware of the risk of sick sinus syndrome because GRNX is frequently prescribed in outpatient clinics.