Toshitaka Iwasaki

Better stent expansion by two-time inflation of stent balloon and its responsible mechanism

OBJECTIVES We determined the effect of two-time inflation of the stent balloon on stent expansion and its responsible factor. METHODS Subjects included 61 patients with de novo coronary artery lesions, in whom 12 sirolimus-eluting, 27 paclitaxel-eluting, and 22 other stents were deployed twice at identical inflation pressures (11.3±2.3 atm) and inflation times (5, 10, 20, and 40 s). After the first and second deployments, minimum lumen diameter (MLD), minimum lumen area (MLA), and distensibility index (DI) were determined using intravascular ultrasound. RESULTS After the second inflation, MLA was significantly increased (5 s: 12.9%, 10 s: 14.5%, 20 s: 9.4%, 40 s: 9.5%). MLD and DI were also significantly increased. In the single and double inflation groups, DI in each group was significantly correlated with inflation time (single: r=0.409, double: r=0.351). DI was not significantly different between double 5-s and single 10-s inflations, between double 10-s and single 20-s inflations, or between double 20-s and single 40-s inflations. Additional stent balloon inflation by higher pressure in 30% and another balloon in 18% of the patients were required. CONCLUSIONS Two-time stent balloon inflation may allow better stent expansion regardless of inflation time and two-time inflation may be equivalent to longer inflation.

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.

Effects of low-dose pioglitazone on glucose control, lipid profiles, renin-angiotensin-aldosterone system and natriuretic peptides in diabetic patients with coronary artery disease

Background: Pioglitazone ameliorates insulin resistance, but has an adverse effect of oedema that may result in subsequent heart failure, especially in diabetic patients with coronary artery disease. In this study, we evaluated the effects of low-dose pioglitazone on glucose control, lipid profiles, renin-angiotensin-aldosterone (RAA) system and natriuretic peptides in diabetic patients with coronary artery disease. Methods and results: We studied 22 diabetic patients with coronary artery disease and more than 40% of left ventricular ejection fraction (LVEF). Patients were treated with 15 mg of pioglitazone for 12 weeks, in addition to their other hypoglycaemic agents. Pioglitazone significantly decreased fasting blood glucose (155.2±52.9 mg/dl to 131.1±38.4 mg/dl, p<0.01) and haemoglobin A1C (7.13±0.44 to 6.69±0.47, p<0.001). It did not affect low-density lipoprotein cholesterol and high-density lipoprotein cholesterol, but significantly decreased triglyceride (115.6±28.8 mg/dl to 99.4±30.0 mg/dl, p<0.05) and atherogenic index of plasma (0.28±0.17 to 0.19±0.16, p<0.05). Pioglitazone did not affect plasma renin activity, plasma aldosterone, human atrial natriuretic peptide or N-terminal pro-brain natriuretic peptide. Conclusion: Our data suggested that low-dose pioglitazone was a safe and useful agent at least in diabetic patients with coronary artery disease and preserved LVEF.

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).

Effect of body mass index on the location of the right adrenal vein in patients with primary aldosteronism

Background: Variable location of the orifice of the right adrenal vein appears to be associated with a poor success rate of sampling, especially in less experienced hands. We described the spectrum of the location of the right adrenal vein, and identified the relation of its location to body mass index in patients with primary aldosteronism. Methods and results: The study population consisted of 95 patients with primary aldosteronism who underwent adrenal venous sampling. On the basis of the anterior view of the right adrenal venogram, the cranio-caudal level of the orifice of right adrenal vein was determined relative to vertebral bodies and disks. In 93 (98%) of the 95 patients, the orifice was located at a level ranging from the upper segment of T11 to the upper segment of L1. In the remaining two patients, it was located at the level of the lower segment of T10. High body mass index was associated with the higher level of the orifice of right adrenal vein. Conclusion: Our data suggested that the location of the orifice of right adrenal vein was largely related to body mass index in patients with primary aldosteronism.

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.