Takaya Fukuyama

Iodine-123 metaiodobenzylguanidine images reflect intense myocardial adrenergic nervous activity in congestive heart failure independent of underlying cause

OBJECTIVES This study was undertaken to assess myocardial adrenergic activity using iodine-123 metaiodobenzylguanidine (MIBG) imaging in patients with heart failure. BACKGROUND In patients with congestive heart failure, adrenergic nerve activity is accelerated. However, whether myocardial adrenergic nerve activity reflects the severity of heart failure and its relation to the underlying cause have not yet been elucidated. METHODS Planar MIBG images were obtained from 96 patients with heart failure and compared with images from 9 age-matched healthy subjects. Groups 1 and 2 included 65 patients with heart failure related to impaired myocardial function and whose left ventricular ejection fraction was < 40% (group 1 = 40 patients with dilated cardiomyopathy; group 2 = 25 patients with ischemic cardiomyopathy). Group 3 included 31 patients with heart failure related to a mechanical abnormality and whose left ventricular ejection fraction was > 40% (mitral regurgitation in 16, aortic regurgitation in 9, aortic and mitral regurgitation in 4, ruptured aneurysm of Valsalva in 2). Myocardial uptake of MIBG was calculated as the heart/mediastinal activity ratio. Storage and release of MIBG were calculated as percent myocardial MIBG washout from 15 min to 4 h after isotope injection. RESULTS The heart/mediastinal activity ratio in the immediate images (15 min) showed a significant decrease only in patients with severe heart failure (groups 1 and 2). The myocardial washout was accelerated in all three heart failure groups. The level of myocardial washout was related to severity of heart failure and correlated well with New York Heart Association functional classification. CONCLUSIONS In severe heart failure associated with cardiomyopathy, norepinephrine uptake is reduced. In addition, myocardial adrenergic nerve activity is accelerated in proportion to severity of heart failure, independent of the underlying cause.

Characterization of Hyperintense Plaque With Noncontrast T1-Weighted Cardiac Magnetic Resonance Coronary Plaque Imaging: Comparison With Multislice Computed Tomography and Intravascular Ultrasound

OBJECTIVES This study sought to characterize coronary hyperintense plaques (HIP) using noncontrast T(1)-weighted imaging (T1WI) in cardiac magnetic resonance, which was then compared with multislice computed tomography and intravascular ultrasound. BACKGROUND Carotid plaque components such as intraplaque hemorrhages and/or lipid-rich necrotic cores can be detected as HIP by noncontrast T1WI. Although coronary HIPs have been successfully detected using this technique, the properties of hyperintense signals in coronary plaques have not yet been systematically evaluated. METHODS Thirty-eight lesions from 37 patients with angina pectoris who demonstrated >70% coronary stenosis on multislice computed tomography were evaluated by noncontrast T1WI using a 1.5-T magnetic resonance imager, and 25 lesions were evaluated by intravascular ultrasound. Signal intensity of coronary plaque to cardiac muscle ratio >1.0 was defined as HIP. We divided 25 lesions into the 2 groups, according to the presence or absence of HIP: HIP (n = 18) and non-HIP (n = 7) groups. RESULTS In comparison with the non-HIP group, the HIP group demonstrated significantly higher coronary plaque to cardiac muscle ratio (1.7 +/- 0.7 vs. 0.9 +/- 0.1, p < 0.01), higher frequency of positive remodeling as observed by both multislice computed tomography (89% vs. 0%, p<0.0001) and intravascular ultrasound (94% vs. 14%, p < 0.001) and ultrasound attenuation (100% vs. 14.3%, p < 0.0001). The frequency of spotty calcification tended to be higher in HIP (89% vs. 50%, p = 0.079). The HIP group also exhibited a significantly lower computed tomography density (-23.2 +/- 20.7 Hounsfield units [HU] vs. 9.6 +/- 20.5 HU, p < 0.01). In addition, the incidence of transient slow-flow phenomena was significantly higher in the HIP group than in the non-HIP group (83% vs. 14%, p < 0.01). CONCLUSIONS The typical HIP case was associated with ultrasound attenuation, positive remodeling, remarkably low computed tomography density, and a high incidence of slow-flow phenomena. Noncontrast T1WI in cardiac magnetic resonance imaging may be useful for the assessment of coronary plaque characterization in patients with coronary artery disease.

Myocardial adrenergic nervous activity is intensified in patients with heart failure without left ventricular volume or pressure overload

OBJECTIVES To clarify whether myocardial adrenergic activity is different in patients with heart failure without left ventricular volume or pressure overload, we used iodine-123 metaiodobenzylguanidine (MIBG) imaging to study patients with mitral stenosis. BACKGROUND In patients with heart failure due to cardiomyopathy or to valve diseases with volume or pressure overload, or both, myocardial adrenergic nerve activity is accelerated independent of underlying cause. However, it is not clear whether this change in myocardial adrenergic nerve activity is present in patients without left ventricular volume or pressure overload. METHODS The study patients were 20 men and women with normal left ventricular function and heart failure due to mitral stenosis. Planar MIBG images obtained from these patients were compared with images from nine age-matched healthy subjects (control group). Myocardial uptake of MIBG was calculated as the heart/mediastinal activity ratio. Storage and release of MIBG were calculated as percent myocardial MIBG washout from 15 min to 4 h after isotope injection. All 20 study patients underwent echocardiography, and 16 underwent right heart catheterization. RESULTS The heart/mediastinal activity ratio in the immediate images (15 min) did not show any significant difference between the patient and control groups. Myocardial washout was increased in patients with severe heart failure. The level of myocardial washout correlated with left atrial diameter (r = 0.51, p = 0.02) and mitral valve area calculated with Doppler echocardiography (r = -0.61, p < 0.01) and mitral valve area calculated with cardiac catheterization (r = -0.62, p = 0.02). The closest correlation existed between myocardial washout and cardiac output (r = -0.80, p < 0.01). CONCLUSIONS In heart failure due to mitral stenosis, myocardial adrenergic nerve activity is intensified. A decrease in cardiac output associated with mitral stenosis acts as a potent stimulus for this intensification.

The bifurcation study using 64 multislice computed tomography.

Background: Various two‐stent techniques have been applied to aggressively treat bifurcation lesions as the introduction of drug‐eluting stents (DES) and the importance of the bifurcation angle and three‐dimensional (3D) structure has come to be recognized. Recent 64 multislice computed tomography (MSCT) technology provides accurate information about the 3D bifurcation geometry of the coronary arteries and with reproducibility. Objectives: The purpose of this study is to disclose the coronary bifurcation angle and 3D structure in humans and elucidate the importance of bifurcation angle for the crush technique using MSCT. Methods: Two hundred and nine patients who were suspected to have angina pectoris and underwent CT angiography using MSCT were examined. The 3D‐volume rendering (VR) image was reconstructed by two technicians and was used for the assessment of each coronary bifurcation angles. Results: The average LMT bifurcation angles (∠LMT‐LAD, ∠LMT‐LCx, ∠LAD‐LCx) were 143 ± 13°, 121 ± 21°, and 72 ± 22°, respectively, the average ∠LAD‐D was 138 ± 19°, the average ∠LCx‐OM was 134 ± 23°, the average distal RCA bifurcation angles (∠RCA‐4AV, ∠RCA‐4PD, ∠4AV‐4PD) were 152 ± 15°, 137 ± 20°, and 61 ± 21°, respectively. In addition, a percentage of steep angled bifurcation (<110°) was significantly higher in the LMT (26%) than in other bifurcations (P < 0.05). Conclusions: LMT bifurcation has been shown to have a higher rate of steep angled bifurcation in humans, it is therefore necessary to take the bifurcation angle into consideration in the case of LMT stenting. These data suggest that a bifurcation study using MSCT can clarify the 3D structure of coronary bifurcation and may provide useful information for bifurcation stenting.

Effects of nitroglycerin and dipyridamole on regional myocardial blood flow.

SummaryThe effects of intravenous administration of nitroglycerin or dipyridamole on distribution of myocardial blood flow in the heart after coronary underperfusion were investigated. In 18 open chest, anesthetized dogs, flow of the tubing supplying the left circumflex coronary artery (LCA) was reduced and kept constant, and then the drug was given intravenously. Before and after an administration of saline, nitroglycerin (0.04 mg/kg) and dipyridamole (0.2 mg/kg), myocardial blood flow was measured by tracer microspheres (TM). The first and second carbonized 15 μ spheres (TM1 and TM2) were injected into the left atrium and the cannulated LCA perfusion system respectively before medication. Similarly, the third and fourth spheres were given after drug. Thus, by using four different TMs (141Ce,51Cr,85Sr,46Sc) regional myocardial blood flow from the LCA perfusion route (TM2 and TM4) was measured separately from that of the other normally perfused coronary route (TM1 and TM3). The effect of drugs on flow distribution of these two independent routes was measured.The LCA underperfusion produced a significant diminution of regional flow and its end/epi ratio in the LCA territory. Nitroglycerin increased end/epi ratio in the ischemic myocardium in the LCA perfusion route, but dipyridamole increased the normally perfused coronary flow but caused a shift of flow from the ischemic left ventricle to the atria and right ventricle within the LCA territory.ZusammenfassungDie Auswirkungen einer intravenösen Verabfolgung von Nitroglycerin und Dipyridamol auf die Verteilung der Blutströmung im Herzen nach koronarer Mangelperfusion wurde untersucht. Bei 18 narkotisierten Hunden mit eröffnetem Thorax wurde der Zufluß zum Ram. circumflexus der linken Koronararterie (LCA) reduziert und konstant gehalten. Dann wurde die Substanz intravenös injiziert. Vor und nach Verabfolgung von Kochsalz, Nitroglycerin (0,04 mg/kg) und Dipyridamol (0,2 mg/kg) wurde die myokardiale Stromstärke nach der Microsphere-Methode gemessen. Die erste und zweite Dosis der Kügelchen (TM1 und TM2) wurde vor der Medikation in den linken Vorhof bzw. in das Perfusionssystem des kanulierten Ram. circumflexus injiziert. In ähnlicher Weise wurde eine dritte und vierte Dosis von Microspheres nach der Medikation verabfolgt. So wurde durch vier verschiedene Gaben von Microspheres (141Ce,51Cr,85Sr,46Sc) die regionale Blutströmung, ausgehend vom Perfusionssystem des Ram. circumflexus (TM2 und TM4) getrennt gemessen von dem übrigen, normalperfundierten Koronarsystem (TM1 und TM3). Der Einfluß der Substanzen auf die Verteilung der Blutströmung in diesen beiden unabhängigen Bereichen wurde gemessen. Die Mangelperfusion des Ram. circumflexus bewirkte eine eindeutige Verminderung der regionalen Blutströmung und des Verhältnisses von endokardialer zu epikardialer Region im Versorgungsbereich des Ram. circumflexus.Nitroglycerin erhöhte im Perfusionsbereich des Ram. circumflexus dieses Verhältnis innerhalb des ischämischen Myokards. Dipyridamol dagegen erhöhte die Stromstärke im übrigen Koronarsystem, verursachte aber eine Verlagerung der Stromstärke vom ischämischen Bereich zu den Vorhöfen und zum rechten Ventrikel im Versorgungsbereich des Ram. circumflexus.

Impact of a prolonged delivery inflation time for optimal drug-eluting stent expansion†

Purpose: We examined the importance of prolonged inflation time for optimal sirolimus‐eluting stent (SES) or paclitaxel‐eluting stent (PES) expansion. Methods: Eighty‐one de novo lesions deployed single SES or PES between April 2007 and March 2008 were divided into four groups; group 1: 21 SES deployed at 20 atm × 60 sec, group 2: 20 SES deployed with 2‐step inflation at 20 atm × 60 sec following 20 atm × 20 sec, group 3: 20 PES deployed same as group 1, group 4: 20 PES deployed same as group 2. The minimal lumen diameter (MLD) and stent expansion ratio (SER; stent cross‐ sectional area at lesion/balloon cross‐sectional area which was calculated according to the compliance chart at the same atmosphere as stent deployment) were compared between group 1 and group 2 in SES, between group 3 and group 4 in PES. Results: The MLD of post 60 sec was significantly higher than that of post 20sec (2.84 ± 0.28 mm in group 1, 2.76 ± 0.33 mm in group 2 vs. 2.54 ± 0.33 mm in group 2; P = 0.003, 0.045, respectively and 2.94 ± 0.28 mm in group 3, 3.00 ± 0.34 mm in group 4 vs. 2.69 ± 0.35 mm in group 4; P = 0.022, 0.007, respectively). The SER of post 60 sec was significantly higher than that of post 20 sec (79.3% ± 8.5% in group 1, 80.8% ± 7.8% in group 2 vs. 71.1% ± 10.2% in group 2; P = 0.014, 0.011, respectively and 81.1% ± 7.9% in group 3, 84.3% ± 9.9% in group 4 vs. 72.6% ± 10.5% in group 4, P = 0.011, 0.001, respectively). Conclusion: The prolonged delivery inflation for 60 sec may result in a more optimal stent expansion. It is therefore considered to be a useful method for deploying drug‐eluting stent.

Prognostic value of myocardial MIBG scintigraphy findings in patients with cardiomyopathy—Importance of background correction for quantification of MIBG activity

Objective: To assess the prognostic value of I-123 metaiodobenzylguanidine, (MIBG) scintigraphy findings, and establish the most appropriate method for calculating myocardial MIBG activity in patients with left ventricular dysfunction due to cardiomyopathy (CM).Methods: Predictors of cardiac death related to progressive heart failure (HF) were examined in 150 patients with CM (80 patients with idiopathic CM and 70 patients with ischemic CM). All patients underwent MIBG scintigraphy at rest and other hemodynamic studies when their clinical status was stable. MIBG scintigrams were obtained 15 minutes and 4 hours after the injection of the isotope. The parameters for quantification of myocardial MIBG activity were heart/mediastinal activity ratio (H/M) and myocardial washout rate (WR). The WR was calculated with and without background (BG) correction.Results: The WR showed better, correlation with plasma norepinephrine and left ventricular ejection fraction after BG correction. During a mean follow-up period of 33±9 (7 to 54) months, 12 patients died due to HF; 7 patients due to progressive HF and 5 patients due to sudden cardiac death. Cox regression analysis indicated, the H/M and the WR with and without BG correction, were significant predictors of cardiac death (Wald chi-squared value: H/M [15 min]=9.7, H/M [4 hr]=19.5, WR with BG correction=29.9, WR without BG correction=12.6). WR prognostic value was better after BG correction, and a high WR with BG correction was the only independent predictor of cardiac death (relative risk [RR]=1.174, p<0.0001).Conclusions: Accelerated WR is a powerful predictor of the patients prognosis and BG correction is essential for calculating WR.

Hyperintense Plaque With Noncontrast T1-Weighted Magnetic Resonance Coronary Plaque Imaging Leading to Acute Coronary Syndrome

A 73-year-old diabetic man underwent multislice computed tomography (MSCT) and noncontrast T1-weighted (T1W) magnetic resonance imaging (MRI) for the evaluation of atypical chest discomfort after an exercise ECG was nondiagnostic. The MSCT demonstrated a low-density positive remodeling plaque and spotty calcification without significant stenosis in the proximal segment of the right coronary artery (Figure 1A and 1B). Noncontrast T1W MRI, using a 1.5-T MR system (Intera, Philips Medical Systems, Best, the Netherlands), revealed a hyperintense plaque (HIP) in the right coronary artery in an area corresponding to …

Normal myocardial perfusion scan portends a benign prognosis independent from the pretest probability of coronary artery disease : Sub-analysis of the J-ACCESS study

BACKGROUND AND PURPOSE We assessed the usefulness of gated stress/rest 99mTc-tetrofosmin myocardial perfusion single photon emission computed tomography (SPECT) to predict ischemic cardiac events in Japanese patients with various estimated pretest probabilities of coronary artery disease (CAD). METHODS AND RESULTS Of the 4031 consecutively registered patients for a J-ACCESS (Japanese Assessment of Cardiac Events and Survival Study by Quantitative Gated SPECT) study, 1904 patients without prior cardiac events were selected. Gated stress/rest myocardial perfusion SPECT was performed and segmental perfusion scores and quantitative gated SPECT results were derived. The pretest probability for having CAD was estimated using the American College of Cardiology/American Heart Association/American College of Physicians-American Society of Internal Medicine guideline data for the management of patients with chronic stable angina, which includes age, gender, and type of chest discomfort. The patients were followed up for three years. During the three-year follow-up period, 96 developed ischemic cardiac events: 17 cardiac deaths, 8 nonfatal myocardial infarction, and 71 clinically driven revascularization. The summed stress score (SSS) was the most powerful independent predictor of all ischemic cardiac events (hazard ratio 1.077, CI 1.045-1.110). Abnormal SSS (> 3) was associated with a significantly higher cardiac event rate in patients with an intermediate to high pretest probability of CAD. Normal SSS (< or = 3) was associated with a low event rate in patients with any pretest probability of CAD. CONCLUSIONS Myocardial perfusion SPECT is useful for further risk-stratification of patients with suspected CAD. The abnormal scan result (SSS > 3) is discriminative for subsequent cardiac events only in the groups with an intermediate to high pretest probability of CAD. The salient result is that normal scan results portend a benign prognosis independent from the pretest probability of CAD.

Quadricuspid aortic valve—Report of a case associated with severe aortic regurgitation and review of the literature—

A case of a 59-year-old woman who had a quadricuspid aortic valve associated with severe aortic regurgitation is reported herein. The anomaly was revealed by aortography, after which the incompetent valve was excised and replaced by a St. Jude Medical prosthesis. A quadricuspid aortic valve must be considered as a malformation which leads to severe valve failure in later life.