Tadanao Higaki

Influence of left ventricular geometry on thallium-201 gated single-photon emission tomographic findings in patients with known or suspected coronary artery disease.

BackgroundRecent studies have shown good correlations between echocardiography and Tl-201 gated single-photon emission computed tomography (SPECT) for the assessment of left ventricular volumes and ejection fraction. We assessed how left ventricular geometry affected correlations between these values measured by the 2 methods in patients with known or suspected coronary artery disease.Methods and resultsThere were 109 patients with normal left ventricular geometry, 20 patients with concentric remodeling, 32 patients with eccentric hypertrophy and 28 patients with concentric hypertrophy. In all 4 groups, there were good correlations between end-diastolic volume (EDV) and end-systolic volume (ESV) values measured by echocardiography and quantitative gated SPECT (QGS). EDV and ESV values measured by QGS were significantly underestimated than those measured by echocardiography except for ESV in eccentric hypertrophy. In all 4 groups, ejection fraction (EF) value measured by echocardiography significantly correlated with that measured by QGS, but Bland–Altman plot showed a proportional error. EF value measured by QGS was likely to be overestimated when EF value increased from the median value, and to be underestimated when EF value decreased from the median value especially in concentric remodeling.ConclusionsTl-201 gated SPECT is a useful tool for the assessment of left ventricular volumes and function, but it requires methodological considerations according to left ventricular geometry.

Effects of myocardial perfusion abnormalities on the accuracy of left ventricular volume and ejection fraction measured by thallium-201 gated single-photon emission tomography: comparison with echocardiography as the reference standard.

BackgroundWe assessed the accuracy of left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) using quantitative gated single-photon emission computed tomography (QGS) in comparison with echocardiography as the reference standard. We also assessed the effects of total perfusion deficit (TPD) on the accuracy of QGS measurements. MethodsA total of 258 patients underwent single-photon emission computed tomography and transthoracic echocardiography within 4 weeks of each investigation for evaluating coronary artery disease. Patients were divided into four groups according to TPD scores. ResultsThere were 138 patients with no/minimal TPD, 64 patients with small TPD, 35 patients with middle TPD, and 21 patients with large TPD. There were good correlations and agreements in EDV (r=0.87, 0.90, 0.71, and 0.94, respectively), ESV (r=0.92, 0.94, 0.79, and 0.94, respectively), and EF (r=0.61, 0.79, 0.61, and 0.83, respectively) between QGS and echocardiography in patients with any TPD. QGS significantly underestimated EDV and ESV in patients with no/minimal or small TPD, and significantly overestimated ESV in patients with large TPD. QGS significantly underestimated EF in patients with middle or large TPD. ConclusionOur results suggest that QGS is a useful tool for assessing the left ventricular volume and function in patients with any TPD, but myocardial perfusion abnormalities should be taken into consideration when interpreting QRS measurements.

Association of mitral annular velocity with myocardial ischemia assessed by single-photon emission computed tomography in patients with suspected coronary artery disease and preserved ejection fraction.

BackgroundLeft ventricular diastolic dysfunction is a sensitive and early sign of myocardial ischemia. We assessed whether mitral annular velocity reflected the severity of myocardial ischemia evaluated by single-photon emission computed tomography in patients with suspected coronary artery disease (CAD) and preserved ejection fraction. Methods and resultsThe study population consisted of 125 patients with suspected CAD who underwent both single-photon emission computed tomography and transthoracic echocardiography. There were 68 patients with no ischemia, 42 patients with mild ischemia, and 15 patients with severe ischemia. With increasing severity of myocardial ischemia, septal e’ decreased. Compared with patients with no ischemia, septal e’ was significantly lower even in patients with mild ischemia (6.6±1.4 vs. 6.1±1.4 cm/s, P<0.05). Septal E/e’ (9.9±2.6 vs. 13.6±4.0, P<0.01) and lateral E/e’ (7.7±2.3 vs. 10.3±3.6, P<0.01) were significantly higher finally in patients with severe ischemia. Multivariate logistic regression analyses showed that BMI [odds ratio (OR) 1.13, 95% confidence interval (CI) 1.01–1.29; P=0.03] and septal e’ (OR 0.71, 95% CI 0.53–0.94; P=0.02) were independent predictors of any myocardial ischemia and that diabetes (OR 5.78, 95% CI 1.58–23.0; P=0.008) and septal E/e’ (OR 1.38, 95% CI 1.13–1.76; P=0.001) were independent predictors of severe myocardial ischemia. ConclusionOur data suggested that decreased e’ was useful in detecting mild myocardial ischemia and increased E/e’ was useful in detecting severe myocardial ischemia in patients with suspected CAD and preserved ejection fraction.

Reduction of Central Blood Pressure in Response to Oral Glucose Loading Is Blunted in Patients With Diabetes Mellitus

BACKGROUND Recent studies have shown that arterial stiffness is reduced after meal intake. We evaluated the acute response of central hemodynamics to glucose loading and the variation in their responses among normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and diabetes mellitus (DM). METHODS The study enrolled 85 patients with known or suspected coronary artery disease who underwent a 75-g oral glucose tolerance test. Central hemodynamic measurements were assessed using radial applanation tonometry at fasting, 60, and 120 minutes after glucose loading. RESULTS Glucose loading decreased the augmentation index normalized to a heart rate of 75 bpm (AIx@75) (81.6±13.9 to 74.5±14.1%, P < 0.01) and central systolic blood pressure (SBP) (115±22 to 109±21mm Hg, P < 0.01) at 120 minutes without a significant change in brachial SBP (126±25 to 125±25mm Hg, P = 0.93). Glucose loading decreased central SBP in NGT and IGT groups but did not affect the DM group. Change in AIx@75 at 120 minutes after glucose loading was blunted in IGT and DM groups compared with the NGT group (-5.7±4.4 vs. -3.6±4.1 vs. -9.3±6.2%, P < 0.01). Multivariate logistic regression analysis identified DM as an independent factor associated with the presence of blunted response of AIx to glucose loading. CONCLUSIONS Oral glucose loading decreased central SBP and AIx@75 without a significant change in brachial SBP, and these central hemodynamic responses were blunted in patients with DM.

Impact of Malondialdehyde-Modified Low-Density Lipoprotein on Tissue Characteristics in Patients With Stable Coronary Artery Disease – Integrated Backscatter-Intravascular Ultrasound Study –

BACKGROUND Malondialdehyde-modified low-density lipoprotein (MDA-LDL) is considered to play an essential role in plaque destabilization. We aimed to investigate the association between the tissue characteristics of culprit plaque assessed by integrated backscatter (IB)-intravascular ultrasound (IVUS) and the serum MDA-LDL levels in patients with stable coronary artery disease. METHODSANDRESULTS The study group consisted of 179 patients undergoing IB-IVUS during elective percutaneous coronary intervention. Patients were classified into 2 groups based on serum MDA-LDL level: low MDA-LDL group (<102 U/L, n=88) and high MDA-LDL group (≥102 U/L, n=91). Plaques in the high MDA-LDL group had higher %lipid (45.2±12.5% vs. 54.9±14.5%, P<0.001) and lower %fibrosis (43.0±9.1% vs. 36.4±11.4%, P<0.001) than did plaques in the low MDA-LDL group. Lipid-rich plaque (%lipid >60% or %fibrosis <30%) was significantly more frequently found in the high MDA-LDL group than in the low MDA-LDL group (14.3% vs. 39.8%, P<0.001). The incidence of MACE (cardiac death, myocardial infarction and/or hospitalization for heart failure) during 3 years was significantly higher in the high MDA-LDL group than in the low MDA-LDL group (6.6% vs. 15.9%, P=0.02). CONCLUSIONS Higher MDA-LDL might be associated with greater lipid and lower fibrous content, contributing to coronary plaque vulnerability. (Circ J 2016; 80: 2173-2182).

Usefulness of aortic knob width on chest radiography to predict central hemodynamics in patients with known or suspected coronary artery disease

Abstract Background: Aortic knob width on chest radiography is independently related to cardiovascular disease. However, little is known about the correlation between aortic knob width and central hemodynamics. Methods: Central blood pressure was measured invasively with diagnostic catheter in 92 patients with known or suspected coronary artery disease. Results: Aortic knob width was positively associated with age (r = 0.42; p < 0.001), central systolic blood pressure (r = 0.35; p < 0.001) and central pulse pressure (r = 0.34; p < 0.001). Multivariate analysis showed that larger aortic knob width was independently related to the higher central systolic blood pressure. Conclusions: Lager aortic knob width on chest radiography is an independent predictor of increase of central systolic blood pressure.

Predictive value of plaque morphology assessed by frequency-domain optical coherence tomography for impaired microvascular perfusion after elective stent implantation: the intracoronary electrocardiogram study

Aims This study was undertaken to assess the association between plaque features at culprit lesions assessed by frequency-domain optical coherence tomography (FD-OCT) and impaired microvascular perfusion estimated by intracoronary electrocardiogram (IcECG) after elective percutaneous coronary intervention (PCI). Furthermore, we investigated whether IcECG could predict future cardiac events. Methods and results This study consisted of 84 patients who underwent both FD-OCT and IcECG during PCI. Patients were classified into two groups based on ST-segment elevation (ST-E) on IcECG after the procedure; ST-E (-) group (n = 53) and ST-E (+) group (n = 31). Minimum fibrous cap thickness was significantly thinner in the ST-E (+) group than in the ST-E (-) group (240 μm [IQR 180 to 310] vs. 100 μm [IQR 60 to 120], P < 0.001). Plaque rupture (7.5% vs. 35.5%, P = 0.001), lipid-rich plaque (75.5% vs. 100%, P < 0.001), the thin cap fibroatheroma (0% vs. 25.8%, P < 0.001) on pre-FD-OCT, protrusion (18.9% vs. 56.7%, P < 0.001), and intra-stent dissection (15.1% vs. 50.0%, P < 0.001) on post-FD-OCT were significantly more frequently found in the ST-E (+) group than in the ST-E (-) group. The incidence of MACE (cardiac death, myocardial infarction, revascularization, hospitalization for heart failure) during 1-year was significantly higher in the ST-E (+) group than in the ST-E (-) group (5.7% vs. 19.4%, P < 0.05). Conclusion Plaque features assessed by FD-OCT might be associated with impaired microvascular perfusion and ST-segment elevation on IcECG after the procedure could predict 1-year cardiac events after elective PCI.

Effects of Cardiac Hemodynamics on Agreement in the pH, HCO3- and Lactate Levels between Arterial and Venous Blood Samples in Patients with Known or Suspected Chronic Heart Failure

OBJECTIVE Analyses of arterial blood gas parameters, including pH, HCO3- and lactate, play an important role in assessing the clinical status of patients with heart failure. In the present study, we evaluated the degree of agreement in the pH, HCO3- and lactate levels between arterial and venous blood samples according to the subset of the Forrester classification. METHODS The study population consisted of 128 patients with known or suspected heart failure. The subjects were divided into four groups based on the Forrester classification. Arterial blood samples were drawn from the radial or brachial artery, and venous blood samples were drawn from the pulmonary artery. RESULTS There were 59 patients with a Forrester subset I status, 32 patients with a subset II status, 21 patients with a subset III status and 16 patients with a subset IV status. The pH and HCO3- levels were similar between the four subsets. In all subsets, the pH values were significantly higher and the HCO3- values were significantly lower in the arterial blood samples than in the venous blood samples. There was good correlation and agreement in the pH and HCO3- levels between the arterial and venous blood samples. In contrast, there was a significant difference in the lactate levels in both the arterial and venous blood samples between the four subsets, and the lactate levels were highest in subset IV. In all subsets, there was good correlation and agreement in the lactate levels between the arterial and venous blood samples. CONCLUSION These data suggest that the venous pH, HCO3- and lactate levels are acceptable substitutes for arterial parameters, regardless of the cardiac hemodynamics.

Use of the Augmentation Index from Applanation Tonometry of the Radial Artery for Assessing the Extent of Coronary Artery Calcium as Assessed by Coronary Computed Tomography

ABSTRACT Background: The augmentation index (AI) obtained from applanation tonometry of the radial artery is technically the easiest and quickest of available methods for assessing arterial stiffness. We tested the hypothesis that the radial AI is associated with the extent of coronary artery calcium (CAC) as assessed by coronary computed tomography (CCT). Methods and Results: This study included 161 patients with known or suspected coronary artery disease undergoing central hemodynamic measurements and CCT. Radial AI was recorded and was corrected in accordance with heart rate (radial AI@75). Thirty-seven patients had no CAC (CAC score = 0), 85 had low-grade CAC (CAC score = 1–399), and 39 had high-grade CAC (CAC score ≥400). Coronary risk factors, except for age and serum creatinine, were similar among the three groups. There were significant differences in brachial systolic blood pressure (SBP) (p = 0.011) and radial AI@75 (%) (p = 0.006). Multivariate analysis showed that age (β = 0.27, p = 0.001), serum creatinine (β = 0.18, p = 0.03), and radial AI@75 (β = 0.24, p = 0.005) were significantly associated with ln (CAC score + 1), whereas brachial SBP was not. Additionally, serum creatinine (odds ratio: 11.91, 95% confidence interval: 1.46–112.0, p = 0.02) and radial AI@75 (per 10%) (odds ratio: 1.76, 95% confidence interval: 1.22–2.64, p = 0.002) were independent factors associated with high-grade CAC. Conclusions: Our results suggest that the radial AI is better for estimating CAC than brachial SBP in patients with known or suspected coronary artery disease.

Nitroglycerine-induced vasodilation in coronary and brachial arteries in patients with suspected coronary artery disease

BACKGROUND Nitroglycerine-induced vasodilation, an index of endothelium-independent vasodilation, is measured for the assessment of vascular smooth muscle cell function or alterations of vascular structure. Both coronary and brachial artery responses to nitroglycerine have been demonstrated to be independent prognostic markers of cardiovascular events. The purpose of this study was to evaluate the nitroglycerine-induced vasodilation in coronary and brachial arteries in the same patients. METHODS We measured nitroglycerine-induced vasodilation in coronary and brachial arteries in 30 subjects with suspected coronary artery disease who underwent coronary angiography (19 men and 11 women; mean age, 69.0±8.8years; age range, 42-85years). RESULTS AND CONCLUSIONS The mean values of nitroglycerine-induced vasodilation in the brachial artery, left anterior descending coronary artery, and left circumflex coronary artery were 12.6±5.2%, 11.6±10.3%, and 11.9±11.0%, respectively. Nitroglycerine-induced vasodilation in the brachial artery correlated significantly with that in the left anterior descending coronary artery (r=0.43, P=0.02) and that in the left circumflex coronary artery (r=0.49, P=0.006). There was also a significant correlation between nitroglycerine-induced vasodilation in the left anterior descending coronary artery and that in the left circumflex coronary artery (r=0.72, P<0.001). These findings suggest that vascular smooth muscle cell dysfunction is a systemic disorder and thus impairment of endothelium-independent vasodilation in peripheral arteries and that in coronary arteries are simultaneously present. Nitroglycerine-induced vasodilation in the brachial artery could be used as a surrogate for that in a coronary artery and as a prognostic marker for cardiovascular events.