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Biomedical subjects

Kenji Takazawa

Publications and source records attributed to Kenji Takazawa.

At least 19 recordsLinked to original sources
PubMed2006

Cibenzoline improves coronary flow velocity reserve in patients with hypertrophic obstructive cardiomyopathy.

The effect of cibenzoline, a class-Ia antiarrhythmic drug, on coronary flow velocity reserve (CFVR) was examined in patients with hypertrophic cardiomyopathy using transthoracic Doppler echocardiography. Coronary flow velocity reserve was assessed in 11 patients with hypertrophic obstructive cardiomyopathy (HOCM) and 12 patients with hypertrophic nonobstructive cardiomyopathy (HNCM), before and after the intravenous administration of cibenzoline (1 mg/kg). Coronary hyperemia was induced by an intravenous infusion of adenosine triphosphate and CFVR was calculated as the ratio of hyperemic to basal mean coronary diastolic flow velocity. At baseline, CFVR was significantly correlated with left ventricular outflow tract pressure gradient (LVPG) in patients with HOCM (r = 0.67, P < 0.03). In patients with HOCM, administration of cibenzoline significantly improved impaired CFVR (2.0 +/- 0.8 to 3.0 +/- 1.0, P < 0.001), and reduced LVPG (55 +/- 30 to 23 +/- 18 mmHg, P < 0.001), while CFVR remained unchanged in patients with HNCM (2.6 +/- 0.9 to 2.9 +/- 0.8, P not significant). Cibenzoline not only reduces LVPG but also improves CFVR in patients with HOCM. In addition left ventricular outflow obstruction plays an important role in impaired coronary circulation in patients with HOCM.

Adenosine Triphosphate↗
PubMed2006

Mild hypertension in young Kurosawa and Kusanagi-hypercholesterolaemic (KHC) rabbits.

The coexistence of hypertension and hypercholesterolaemia from youth may increase the prevalence of and mortality from cardiovascular disease and stroke. We thus investigated haemodynamics of mild hypertension in young Kurosawa and Kusanagi-hypercholesterolaemic (KHC) rabbits aged 10-12 months old, as models of heritable hypercholesterolaemia. Pressure and flow waves were simultaneously recorded at the ascending aorta with a catheter-tip micromanometer and ultrasonic flow meter under pentobarbital anaesthesia, respectively. Systolic (119.3 +/- 6.5 and 138.4 +/- 7.4 mmHg (mean +/- SD) for control and KHC rabbit groups; p < 0.001), diastolic (95.7 +/- 6.1 and 109.8 +/- 5.2; p < 0.001), mean (105.8 +/- 6.5 and 122.5 +/- 4.9; p < 0.001) and pulse (23.7 +/- 2.5 and 28.6 +/- 4.0; p < 0.001) pressures as well as total peripheral vascular resistance (0.32 +/- 0.02 and 0.37 +/- 0.03 mmHg/ml/min; p < 0.001) were significantly greater in the KHC rabbit group than those in the age-matched control rabbit group, respectively, while there were no significant differences in the mean aortic flow, heart rate or stroke volume between the two rabbit groups. Aortic input impedance (p < 0.05) and reflection coefficient (p < 0.05) were significantly greater at lower frequency in the KHC rabbit group than in the control rabbit group, whereas there was no significant difference in the characteristic impedance between the two rabbit groups. Plasma angiotensin I (p < 0.01) and II (p < 0.01) levels and serum angiotensin converting enzyme activity (p < 0.05) were significantly greater in the KHC rabbit group than in the age-matched control rabbit group. Atheromatous plaque was in the early stage and composed mainly of abundant foam cells. Neither sclerotic lesions nor stenosis were observed in main peripheral arteries. The mild hypertension in young KHC rabbits was due partly to the increased activity of the renin-angiotensin system. These findings may be thought provoking in elucidating the mechanism and developing preventive and therapeutic strategies in young patients with coexistent hypertension and hypercholesterolaemia.

Algorithms↗
PubMed2006

Usefulness of late gadolinium enhancement combined with MRI and 67-Ga scintigraphy in the diagnosis of cardiac sarcoidosis and disease activity evaluation.

We report a case in which late gadolinium enhancement (LGE) and 67-Ga scintigraphy were useful for the diagnosis of cardiac sarcoidosis and for the evaluation of the disease activity. The patient was a 60-year-old woman who had been diagnosed as having eye sarcoidosis when she was 48. Two years previously her electrocardiogram had shown abnormalities but the coronary angiography had shown normal coronary arteries; however, an aneurysm was detected in the apical portion by left ventriculography. A II degree AV block was noted on the electrocardiogram and she was referred to us for further detailed evaluation. Since the biopsy findings of skin eruptions on both eyelids indicated an epithelial cell granuloma, she was diagnosed as having cutaneous sarcoidosis. On the 67-Ga scintigram, myocardial accumulation of gallium was recognized, and on cardiovascular magnetic resonance (CMR), LGE was recognized. She was diagnosed as cardiac sarcoidosis and steroid therapy started with 30 mg prednisolone. The myocardial accumulation of gallium on the 67-Ga scintigram disappeared after the 30th day of steroid therapy. On the other hand, no changes in LGE patterns were seen after steroid therapy. In this case, LGE was useful for the diagnosis of cardiac sarcoidosis, and 67-Ga scintigram was useful for the evaluation of the disease activity. This case shows that both imaging techniques are important for the diagnosis of cardiac sarcoidosis and evaluation of the disease.

Anti-Inflammatory Agents↗
PubMed2006

The role of intravenous coronary thrombolysis for patients with acute myocardial infarction in different treatment strategies.

OBJECTIVE: To examine acute-phase outcomes in acute myocardial infarction (AMI) according to different initial treatments. PATIENTS AND METHODS: This retrospective study involved 405 patients with AMI who had undergone coronary angiography during the acute phase. The patients were retrospectively examined by dividing into groups according to treatment received: intravenous coronary thrombolysis (IVCT) (n=83), intracoronary thrombolysis (ICT) (n=62), and percutaneous coronary intervention (PCI) (n=221). RESULTS: TIMI 3 flow at the initial angiography was higher in the IVCT group (P<0.05) at 32.5% in the IVCT group and 21.7% in the non-IVCT group. The time from onset to initiation of treatment was shorter in the IVCT group (P<0.001) at 227 min in the IVCT group, 337 min in the ICT group, and 479 min in the PCI group. The acute-phase mortality was lower in the IVCT group (P<0.05) at 2.4% in the IVCT group, 3.2% in the ICT group, and 11.8% in the PCI group. According to sub-analysis, the restenosis rate during the chronic phase after PCI did not differ with or without antecedent administration of a thrombolytic agent. CONCLUSION: IVCT as an initial treatment for AMI enabled the fastest reperfusion at TIMI > or = 2 flow, resulting in a good acute-phase outcome.

Aged↗
PubMed2006

Contour analysis of the photoplethysmographic pulse measured at the finger.

Analysis of the contour of the peripheral pulse to assess arterial properties was first described in the nineteenth century. With the recognition of the importance of arterial stiffness there has been a resurgence of interest in pulse wave analysis, particularly the analysis of the radial pressure pulse acquired using a tonometer. An alternative technique utilizes a volume pulse. This may conveniently be acquired optically from a finger (digital volume pulse). Although less widely used, this technique deserves further consideration because of its simplicity and ease of use. As with the pressure pulse, the contour of the digital volume pulse is sensitive to changes in arterial tone induced by vasoactive drugs and is influenced by ageing and large artery stiffness. Measurements taken directly from the digital volume pulse or from its second derivative can be used to assess these properties. This review describes the background to digital volume pulse contour analysis, how the technique relates to contour analysis of the pressure pulse, and current and future applications.

Blood Pressure↗
PubMed2006

Decrease of fractional flow reserve shortly after percutaneous coronary intervention.

BACKGROUND: The aim of the present study was to quantitatively assess the physiological acute recoil after percutaneous coronary intervention (PCI), and to determine the relation between it and target lesion revascularization (TLR) in the chronic phase. METHODS AND RESULTS: This study evaluated 76 patients who underwent elective PCI between May 1997 and December 2001: plain old balloon angioplasty (POBA) in 50 patients and bare metal stent implantation in 26 patients. Fractional flow reserve (FFR) was measured immediately (FFR0m) and 15 min (FFR15m) after the final dilation, and the difference (dif-FFR) was calculated. In POBA patients with TLR, FFR15m was significantly low (0.79+/-0.05 vs 0.87 +/-0.08, p<0.001) and dif-FFR was significantly high (0.06+/-0.04 vs -0.01+/-0.04, p<0.001) compared with the patients without TLR. The patients with a larger dif-FFR value (> or =0.05) had a higher rate of TLR (92%). Dif-FFR was the strongest independent predictor of TLR. CONCLUSIONS: The changes in FFR during the time course shortly after coronary intervention can be detected and a decrease in the first 15 min after PCI is associated with a higher rate of TLR.

Aged↗
PubMed2005

Usefulness of fractional flow reserve in determining the indication of target lesion revascularization.

The objective of this study was to examine the usefulness of fractional flow reserve (FFR) in determining the indication of target lesion revascularization (TLR) at follow-up angiography after percutaneous coronary intervention (PCI). One hundred forty-seven patients with 155 lesions that had intermediate restenosis took part in this study. FFR was measured in all patients for the evaluation of stenosis severity. Then TLR was performed when FFR was < 0.75, and TLR was deferred when FFR was > or = 0.75. Patients in whom TLR was deferred were followed up clinically (25 +/- 11 months). In 98 patients (67%) who underwent stress myocardial scintigraphy before angiography, the results of the scintigraphy were compared with FFR results. TLR was performed in 34 lesions (22%). After TLR, the Canadian Cardiovascular Society class decreased significantly (from 1.5 +/- 0.7 to 1.1 +/- 0.5; P < 0.05). In 113 patients who did not undergo TLR, only 4 patients (3.5%) had cardiac events (re-PCI in 1 patient and a positive SPECT in 3 patients). Discordance between the results of scintigraphy and FFR was observed in 30 patients (30%), but the patients who had good values of FFR > or = 0.75 showed a nil event rate (0%). FFR might be useful for the determination of the indication of TLR.

Aged↗
PubMed2005

Augmentation index in heart disease.

New techniques for the evaluation of specific components of blood pressure waveforms have been shown to have broad applications in cardiology. One of the more useful parameters of pressure wave analysis is the augmentation index (AI), which measures the interaction of the forward pressure wave with reflected waves from the distal circulation. Analysis of AI and associated wave functions show differences related to cardiac risk, the presence of disease, and the effects of drug administration. The AI can provide useful additional information in the evaluation of high-risk populations and is a useful research tool in evaluating drug and treatment effects. New techniques have allowed AI to become more widely available and current measurements are convenient and reliable.

Aging↗
PubMed2005

Clinical efficacy of apple polyphenol for treating cedar pollinosis.

A double-blind comparative study was conducted on cedar pollinosis patients in order to evaluate the treatment efficacy of apple polyphenol (Ap). Ap was administered (500 mg) once daily for 12 weeks, starting about 2 weeks prior to cedar pollen dispersion. Pollinosis symptoms during the study were evaluated according to the classification in the guidelines for allergic rhinitis diagnosis and treatment. The results show that the sneezing score was significantly lower for the Ap group than with the placebo group during the early period of pollen dispersion and during the main dispersion period. In addition, no adverse reactions were induced by Ap during the study. These results suggest that Ap may alleviate the symptoms of cedar pollinosis.

Anti-Allergic Agents↗
PubMed2005

Do eicosapentaenoic acid supplements attenuate age-related increases in arterial stiffness in patients with dyslipidemia?: A preliminary study.

The present study was conducted to examine the effect of eicosapentaenoic acid supplements on pulse wave velocity (PWV) in patients with dyslipidemia as a prospective open-labeled study. Eicosapentaenoic acid supplements (1,800 mg/day) were prescribed to 40 patients, and diet therapy in consultation with a nutritionist was conducted in 44 patients as a control group. These interventions were continued for 12 months, and PWV and blood examinations were performed at the start and end of these interventions. PWV increased in the control group but not in the eicosapentaenoic acid group. After adjustment for age, gender, the initial PWV, and the changes in mean blood pressure during the study period, a general linear model univariate analysis post hoc comparison demonstrated that the change in PWV during the period of study was significantly larger in the control group (42 +/- 20 cm/s) than in the eicosapentaenoic acid group (-9 +/- 19 cm/s) (p<0.05). Thus, this preliminary study suggested that eicosapentaenoic acid supplements attenuate age-related increases in arterial stiffness in patients with dyslipidemia. A further study with a larger number of subjects is proposed to confirm this beneficial effect of eicosapentaenoic acid supplements on arterial stiffness.

Aged↗
PubMed2005

[Assessment of regional myocardial systolic function in hypertensive left ventricular hypertrophy using harmonic myocardial strain imaging].

OBJECTIVES: Regional myocardial systolic function in hypertensive left ventricular hypertrophy was assessed using the newly developed myocardial strain imaging. METHODS: This study included 17 patients with hypertensive left ventricular hypertrophy (LVH group) and 22 normal subjects (N group). The transmural location of the strain peak value (StPP), and the strain peak value (StPV) in the end-systolic phase were measured at the posterior wall by myocardial strain imaging. Left ventricular mass index was simultaneously measured in both groups. RESULTS: StPV was significantly lower in the LVH group than the N group (1.00 +/- 0.36 vs 1.38 +/- 0.42, p < 0.01) and StPP was significantly moved to the epicardium side compared with the N group (31 +/- 10% vs 11 +/- 5%, p < 0.0001). StPV decreased and StPP increased with greater left ventricular mass index (r = -0.61, p < 0.0001; r = 0.72, p < 0.0001, respectively). CONCLUSIONS: Myocardial systolic impairment in hypertensive left ventricular hypertrophy may occur from the endocardium side, and the impairment may progress with increased left ventricular hypertrophy.

Aged↗
PubMed2005

[Intracoronary temperature in patients with coronary artery disease].

OBJECTIVES: Measurements of changes in plaque temperature may predict plaque rupture. The present study investigated variations in temperature within the atherosclerotic coronary artery using a pressure guide wire with thermal sensor (dual sensor guide wire). METHODS AND RESULTS: Seventy-seven patients (78 lesions), who had no significant lesion at the orifice of the culprit coronary artery, were studied. The patients had acute myocardial infarction (22 patients), unstable angina pectoris (20 patients), and stable angina pectoris (35 patients). The thermal sensor was calibrated at the orifice of the coronary artery, and then inserted into the culprit coronary artery. deltaT was defined as the difference between the intracoronary temperature at the position of the pressure gradient and at the orifice. deltaT was higher in patients with acute myocardial infarction and unstable angina pectoris than in patients with stable angina pectoris (0.09 +/- 0.07 and 0.07 +/- 0.07 vs 0.03 +/- 0.04 degrees C, p < 0.001, p = 0.02, respectively). There was no significant difference in deltaT between patients with acute myocardial infarction and unstable angina pectoris (p = 0.48). Patients with acute myocardial infarction and unstable angina pectoris showed a significant relationship between deltaT and C-reactive protein (r = 0.59, p = 0.0004). CONCLUSIONS: The variations in intracoronary temperature of the culprit coronary arteries in patients with acute coronary syndrome were higher than those in patients with stable angina pectoris. These variations may be related to inflammation of vulnerable plaque.

Aged↗
PubMed2004

Comparison of ankle-brachial pressure index and pulse wave velocity as markers of the presence of coronary artery disease in subjects with a high risk of atherosclerotic cardiovascular disease.

Recently, a measurement device that can simultaneously measure the ankle-brachial pressure index (ABI) and brachial-ankle pulse wave velocity (PWV) has become available. The present study compares the applicability of ABI and PWV as markers for predicting the prevalence of coronary artery disease (CAD) in subjects with a high risk of atherosclerotic cardiovascular disease. The ABI and brachial-ankle PWV were measured in 472 consecutive subjects who subsequently underwent coronary angiography for diagnosis or exclusion of CAD. The prevalence of CAD in the lowest ABI quartile was higher than those in the other 3 ABI quartiles, whereas the prevalence in the lowest brachial-ankle PWV quartile was lower than those in the other 3 brachial-ankle PWV quartiles. A multivariate logistic regression analysis demonstrated that the lowest ABI quartile was a significant independent variable for the prevalence of CAD and that the lowest brachial-ankle PWV quartile was a significant independent variable for the absence of CAD in a population. Thus, a low ABI is an independent marker for an additive risk of CAD, whereas a low brachial-ankle PWV may be used as an independent marker for excluding the risk of CAD among subjects with a high risk of atherosclerotic cardiovascular disease.

Aged↗
PubMed2004

ONO-4817, a novel matrix metalloproteinase inhibitor, attenuates allograft vasculopathy in a rat cardiac transplant.

BACKGROUND: Cardiac allograft vasculopathy (CAV), a disorder characterized by rapid development and progression of obliterative vasculopathy in the transplanted heart, continues to be a major cause of graft failure in long-surviving human transplants. The mechanisms and histopathologic processes of CAV remain unknown. Previous animal studies have shown that inhibition of matrix metalloproteinase (MMP) prevents migration and proliferation of smooth muscle cells in CAV. In this study, we hypothesized that MMPs may be expressed in and may play an important role in CAV. METHODS: An F344-to-WKAH rat heterotopic heart transplantation model was used. Tacrolimus was administered intramuscularly 14 days after transplantation to prevent acute rejection and to allow the development of CAV. We divided the animals into 2 groups according to post-operative treatment: an ONO group received an MMP inhibitor (ONO-4817) daily by oral gavage for 14 days after transplantation (n = 6), and a control (n = 6) group received no treatment. Grafts were harvested 60 days after treatment. RESULTS: Immunohistochemical staining revealed that MMP-2 and tissue inhibitors of metalloproteinase-2 (TIMP-2) were expressed more strongly in the neointima and media of the control CAV animals than in the ONO-CAV animals. The animals given ONO-4817 exhibited a significant decrease in the percentage of affected vessels, in the percentage of intimal proliferation, in the intima-to-media ratio, and in the expression of MMP-2 and TIMP-2. CONCLUSION: These results suggest that MMP-2 and TIMP-2 play an important role in the development of CAV and that the use of an MMP inhibitor (ONO-4817) may prevent neointimal proliferation in patients with CAV.

Animals↗
PubMed2004

Application of pressure-derived myocardial fractional flow reserve in assessing the functional severity of coronary artery stenosis in patients with diabetes mellitus.

BACKGROUND: Although the development of a coronary guidewire mounted with a pressure sensor has facilitated the measurement of pressure-derived fractional flow reserve (FFR) to assess the functional severity of coronary artery stenoses, the theoretical limitations include diabetes mellitus because of the associated microvascular abnormalities. METHODS AND RESULTS: In the present study 304 vessels and their coronary territories in 96 diabetic and 149 nondiabetic patients were evaluated by pressure-derived FFR and thallium-201 single photon emission computed tomography (SPECT) to determine the applicability of measuring FFR in diabetic subjects. The best cut-off value for FFR to detect myocardial ischemia, as demonstrated by (201)Tl SPECT, was 0.725 in the diabetic and 0.745 in the nondiabetic patients. Sensitivity and specificity were similar for the 2 groups (83% and 75% (diabetic) vs 79% and 83%). However, diabetic patients with homoglobin (Hb) A(1c) >or=7.0% showed lower specificity in comparison with those having HbA(1c) <7.0% (64 vs 88%; p=0.045); however, sensitivities were similar (83 vs 83%; p=NS). CONCLUSIONS: The cut-off value of 0.75 for FFR can detect myocardial ischemia in diabetic patients, although the adequacy of glycemic control should be taken into consideration when assessing the FFR measurements.

Aged↗
PubMed2004

Synergistic effect of triptolide and tacrolimus on rat cardiac allotransplantation.

Recent studies have shown that triptolide inhibits T cell activation through mechanisms different from those of cyclosporine A and tacrolimus and we postulated that triptolide might have a synergistic effect with tacrolimus to enhance immunosuppression. Using a F344 donor-to-Lewis recipient rat combination, we investigated the immunosuppressive effects of triptolide alone or in combination with tacrolimus on the survival of cardiac allografts. Recipients were treated with placebo, triptolide, tacrolimus, and triptolide in combination with tacrolimus at different doses. The median survival time (MST) was 8 days for placebo; 9.5, 11, 14 and 19 days for triptolide monotherapy at doses of 0.04, 0.08, 0.16, and 0.32 mg/kg/day, respectively, and 11, 13.5, and 52 days for tacrolimus monotherapy at doses of 0.025, 0.05, and 0.1 mg/kg/day, respectively. Tacrolimus 0.025 mg/kg/day combined with triptolide 0.08 and 0.16 mg/kg/day prolonged the MST to 17.5 and 20 days, respectively; while tacrolimus 0.05 mg/kg/day combined with triptolide 0.04, 0.08, and 0.16 mg/kg/day prolonged the MST to 21, 23, and 23 days, respectively. These results suggest that triptolide is a moderately effective immunosuppressive agent. Triptolide combined with a subtherapeutic dose of tacrolimus produced a synergistic effect in prolonging rat cardiac allograft survival.

Animals↗
PubMed2004

Correlation between myocardial uptake of technetium-99m-sestamibi and pressure-derived myocardial fractional flow reserve.

OBJECTIVES: Development of the coronary pressure wire has facilitated the measurement of fractional flow reserve (FFR) to assess the functional severity of coronary artery stenoses. METHODS: This study evaluated the correlations between FFR and myocardial direct counts of technetium-99m(99mTc)-sestamibi in 20 patients (16 men, 4 women, mean age 66 +/- 8 years) who underwent 99mTc-sestamibi single-photon emission computed tomography (SPECT) with the 2-day protocol using 740 MBq of 99mTc-sestamibi each day. Visual assessment of myocardial imaging and quantitative analysis with the measurement of percent uptake and direct count of 99mTc-sestamibi were performed. RESULTS: Visual assessment of myocardial imaging revealed that reversibility of 99mTc-sestamibi perfusion defects was correlated with FFR of < 0.75, which is regarded as functionally important stenosis (17/20 vs 3/20, kappa = 0.71, p < 0.002). Regional reversibility score did not correlate with FFR (r = -0.40, p = NS). Quantitative analysis revealed that the change in 99mTc-sestamibi percent uptake with pharmacologic stress using adenosine triphosphate disodium (ATP) also did not correlate with FFR (r = 0.35, p = NS). In contrast, percent increase in 99mTc direct counts with ATP was lower in patients with FFR of < 0.75 than in those with FFR of > = 0.75 (-4 +/- 16% vs 24 +/- 30%, p < 0.01). In addition, a significant correlation (r = 0.70, p < 0.001) was observed between percent increase in 99mTc direct counts with ATP and FFR. CONCLUSIONS: These results suggest that quantitative analysis of 99mTc-sestamibi scintigraphy enables the assessment of the magnitude of functional significance of coronary stenosis.

Adenosine Triphosphate↗