Images in cardiovascular medicine. Serial assessment of liquefaction necrosis of mitral annular calcification by echocardiography and multislice computed tomography.
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Calcinosis↗
Biomedical subjects
Takaaki Isshiki
Publications and source records attributed to Takaaki Isshiki.
Radiosensitive functional dye: clinical application for estimation of patient skin dose.
Institutional review board approval and informed patient consent were obtained. The purpose of the study was to prospectively evaluate the use of radiosensitive indicators to estimate patient entrance skin dose (ESD). Forty-six patients wore a jacket with 48 or 52 indicators adhered to the back during percutaneous coronary interventions; they had eight additional indicators on their upper arms. The patients' ESDs were calculated according to the change in color of the indicators. There were good correlations between the ESDs estimated by using color measurements performed with an optical instrument and those estimated at visual observation (P < .001) and between the ESDs estimated by using a thermoluminescent dosimeter and those estimated by using color measurements (P < .001). The radiosensitive indicator method seems to be useful for estimating ESDs and their distribution during percutaneous coronary intervention; however, visual observation is reliable for estimating doses of up to 5 Gy only. (c) RSNA, 2006.
Aged↗
Impact of 16-slice computed tomography in percutaneous coronary intervention of chronic total occlusions.
The main reason for failure of percutaneous coronary intervention (PCI) of chronic total occlusion (CTO) is because the calcified plaque prevents the guide wire crossing the occlusion. We aimed to identify the route, and characterize plaque components within CTO, using 16-slice computed tomography (MSCT). Twenty three angiographic CTO in 22 patients (mean age 69 +/- 5 years, 17 males) were included. All patients had undergone MSCT prior to PCI. Images were analyzed for lesion visibility and plaque characteristics of CTO. The presence and location of calcified plaque within the CTO were systematically assessed. Each lesion was classified as a noncalcified, moderately calcified, or exclusively calcified plaque. Procedural failure was defined as the inability to cross a guide wire through the occlusion. All coronary routes of CTO segment were visualized. MSCT revealed three markedly bent CTO segments (13.0%), which could not be identified by coronary angiography only. Calcified plaques were detected in 30 lesions of 19 CTO segments (82.6%), but were not detected in the other four. The majority of calcified plaque was located in the proximal lesion, or both proximal and distal lesions. Fifteen out of 30 calcified lesions (50.0%) were exclusively calcified plaques. Overall procedural success was obtained in 21 CTOs (91.3%). MSCT can accurately identify the route of the CTO segment and evaluate both distribution and amount of the calcified plaque within it. Even with the complicated and/or calcified lesions, PCI success rate was excellent under MSCT guidance. MSCT should become a useful tool in PCI of CTO.
Aged↗
Accuracy of attenuation measurement of vascular wall in vitro on computed tomography angiography: Effect of wall thickness, density of contrast medium, and measurement point.
OBJECTIVES: We sought to assess the effects of measurement point, wall thickness, and intravascular density of contrast material on attenuation measurement of vascular wall. MATERIALS AND METHODS: We used vascular models (actual attenuation value of the wall: 83 HU) with wall thicknesses of 1.5, 1.0, or 0.5 mm, filled with contrast material of 254, 325, or 400 HU. The 9 vascular models were fixed in an oil-filled container and scanned with a 16-detector computed tomography. The wall attenuation values were measured at 1 point for 0.5-mm thickness models, 3 for 1.0-mm thickness models, and 5 for 1.5-mm thickness models with the same interval of 0.25 mm. Total 20 measurements were done for each point. RESULTS: For 1.0-mm and 1.5-mm thickness models, wall attenuation progressively increased as the measurement points approached the lumen (P < 0.0001). At all the measurement points for 0.5-mm and 1.0-mm thickness models and the 2 inner measurement points for 1.5-mm thickness models, the densities of contrast material affected the wall attenuations significantly (P < 0.0001). At the midportion for 1.5-mm thickness models, the wall attenuations were not affected by the densities of the contrast material (P = 0.6301), and were 65-68 HU. CONCLUSIONS: The effects of the intravascular density of contrast material, measurement point, and wall thickness should be considered in the attenuation measurement of the wall.
Angiography↗
Accuracy and efficiency of left ventricular ejection fraction analysis, using multidetector row computed tomography: effect of image reconstruction window within cardiac phase, slice thickness, and interval of short-axis sections.
BACKGROUND: The aim of the present study was to assess the accuracy and efficiency of left ventricular ejection fraction (LVEF) analysis by multidetector row computed tomography (CT). METHODS AND RESULTS: The CT data of 21 patients were analyzed by semi-automated software on a workstation. In analysis of LVEF using systolic volumes in the 6 phases (30-55%), systolic images of 10% interval (35, 45, 55%) were underestimated with a mean measurement error of -0.4% and the standard error of the estimate (SEE) of 0.6%, compared with the LVEF using images of 5% interval. In analysis of LVEF using 3-slice thicknesses of axial images (1, 2, and 3 mm), and 3-slice numbers of short-axis sections (10 14, and 30 slices), there was no significant difference between the SEE of the intraobserver reproducibility and that of the analysis with 30 short-axis sections using axial images of 1-, 2- and 3-mm thickness, and that with 14 short-axis sections using axial images of 1- and 2-mm thickness. The mean analysis times were 96.9 s, 119.8 s, and 227.0 s for the analysis with 10, 14, and 30 short-axis sections, respectively. CONCLUSION: The proper selection of the reconstruction interval in the cardiac phase, the slice thickness of the axial images, and the number of short-axis sections reduces the analysis time, maintaining the accuracy of LVEF analysis. This will be acceptable for practical use at present, although more accurate analysis is preferable.
Adult↗
Radiation exposure to patient's skin during percutaneous coronary intervention for various lesions, including chronic total occlusion.
BACKGROUND: Radiation skin injuries have been reported as a result of various procedures, so in the present study the patients' entrance skin dose (ESD) during percutaneous coronary intervention (PCI) was evaluated. METHODS AND RESULTS: ESDs were assessed during 97 procedures (13 for chronic total occlusion (CTO), 14 for multivessel stenoses, 22 for single-vessel multiple stenoses, and 48 for single stenosis). The patients wore jackets that had 48 or 52 radiosensitive indicators placed on the back during the PCI procedures, with 8 other indicators placed on both upper arms. After the procedure, the color of the indicators was analyzed with a color measuring instrument, and the patients' ESDs were calculated from the color difference of the indicators. The average maximum ESDs of the patients were 4.5 +/- 2.8 Gy (median: 4.6 Gy) for CTO, 2.3 +/- 0.7 Gy (median: 2.4 Gy) for multivessel stenoses, 1.8 +/- 1.0 Gy (median: 1.5 Gy) for single-vessel multiple stenoses, and 1.4 +/- 0.9 Gy (median: 1.2 Gy) for single stenosis. CONCLUSIONS: Skin injury can occur during PCI, especially for CTO, so it is important to estimate each patient's ESD and attempt to reduce it.
Aged↗
Intravascular ultrasound analysis of the radial artery for coronary artery bypass grafting.
BACKGROUND: The radial artery has become a popular conduit for coronary artery bypass surgery. However, limited information has been provided regarding the atherosclerotic nature of this artery, which may affect both the immediate intraoperative difficulties and long-term graft patency. METHODS: We examined intravascular ultrasound (IVUS) images of the radial artery in patients with coronary artery diseases. Cross sections of the radial artery were assessed using the following factors: lumen diameter, lumen area, vessel diameter, vessel area, plaque area, percent plaque area, and extent of calcium deposition. RESULTS: The IVUS images were obtained from radial arteries of 58 patients (47 men, average 67 +/- 9 years) during transradial procedures; ie, transradial coronary angiography and/or transradial coronary intervention. Mean luminal diameter was 3.28 +/- 0.69 mm and 3.00 +/- 0.70 mm at the proximal and distal segments, respectively, and 2.58 +/- 0.73 mm at the minimal lumen cross section. A percent plaque area greater than 50% was seen in five radial arteries (8.6%) whose average plaque length was 26.4 +/- 30.8 mm. Of these, one showed a plaque length greater than 50 mm, and another showed vessel caliber less than 2.0 mm. Five of 58 radial arteries (8.6%) showed calcium deposition, two of which showed diffuse calcification (> 50 mm). Thus, among 58 radial arteries, four (6.9%: one with diffuse arteriosclerosis, one small radial artery, two with diffuse calcification) were considered unsuitable for bypass conduit. CONCLUSIONS: Preoperative evaluation of the radial artery is recommended in order to prevent unnecessary exploration of the forearm and to improve graft patency.
Aged↗
Differential blocking action of dihydropyridine Ca2+ antagonists on a T-type Ca2+ channel (alpha1G) expressed in Xenopus oocytes.
Recent reports show that efonidipine, a dihydropyridine Ca2+ antagonist, has blocking action on T-type Ca2+ channels, which may produce favorable actions on cardiovascular systems. However, the effects of other dihydropyridine Ca2+ antagonists on T-type Ca2+ channels have not been investigated yet. Therefore, in this study, we examined the effects of dihydropyridine compounds clinically used for treatment of hypertension on a T-type Ca2+ channel subtype, alpha1G, expressed in Xenopus oocytes. These effects were compared with those on T-type Ca2+ channel. Rabbit L-type (alpha1Calpha2/deltabeta1a) or rat T-type (alpha1G) Ca2+ channel was expressed in Xenopus oocytes by injection of cRNA for each subunit. The Ba currents through expressed channels were measured by conventional 2-microelectrode voltage-clamp methods. Twelve DHPs (amlodipine, barnidipine, benidipine, cilnidipine, efonidipine, felodipine, manidipine, nicardipine, nifedipine, nilvadipine, nimodipine, nitrendipine) and mibefradil were tested. Cilnidipine, felodipine, nifedipine, nilvadipine, minodipine, and nitrendipine had little effect on the T-type channel. The blocks by drugs at 10 microM were less than 10% at a holding potential of -100 mV. The remaining 6 drugs had blocking action on the T-type channel comparable to that on the L-type channel. The blocking actions were also comparable to that by mibefradil. These results show that many dihydropyridine Ca2+ antagonists have blocking action on the alpha1G channel subtype. The action of dihydropyridine Ca2+ antagonists in clinical treatment should be evaluated on the basis of subtype selectivity.
Animals↗
Evaluation of coronary stents in vitro with CT angiography: effect of stent diameter, convolution kernel, and vessel orientation to the z-axis.
BACKGROUND: The aims of the present study were to assess the effect of the stent diameter, convolution kernel, and vessel orientation to the z-axis on the evaluation of coronary stents, in vitro with computed tomography (CT) angiography. METHODS AND RESULTS: Seven vascular models (2 models without stenosis, 2 with obstruction, and 3 with stenosis) with an approximate inner diameter of 3 or 4 mm, filled with contrast material (79 or 330 HU) were scanned with a 16-detector CT. The diameter measurement of the stent lumen and stenosis evaluation were both done in an orientation parallel to the z-axis of the scanner using 4 convolution kernels. The measured diameters of the stented lumen were 47-57% and 36-45% smaller than the actual inner diameter of the 3- and 4-mm diameter models, respectively. The diameter measurement of the stent lumen and visualization of the in-stent stenosis were improved by using convolution kernels with higher spatial resolution. The in-stent artifacts were evaluated in 4 orientations (0 degrees , 30 degrees , 60 degrees , 90 degrees ) to the z-axis. The artifact was the minimum in 0 degrees to the z-axis, and the maximum in 90 degrees . CONCLUSION: Visualization of the lumen of a stent by CT is affected by its diameter, convolution kernel, and vessel orientation to the z-axis, and these factors should be taken into consideration in the stent evaluation.
Angiography↗
Rates of primary percutaneous coronary intervention worldwide.
BACKGROUND: Primary percutaneous coronary intervention (PCI) is at present the most effective procedure for reducing the mortality rate of patients with acute myocardial infarction (AMI). However, there is a great difference between Japan and other countries in the rate of primary PCI. METHODS AND RESULTS: Registration period, number of patients with AMI, rates of primary PCI or thrombolysis and in-hospital or 30-day mortality rates were analyzed in 3 Japanese, 4 European, 4 American and 2 world-wide databases of AMI. The primary PCI rate is higher (75-94%) in Japan than in the other countries (5.5-49.6%), particularly in low-volume hospitals, and the mortality rates at these centers were similar to those in high-volume hospitals (approximately 4-10%). The primary PCI rate has recently been rising (25-50%) worldwide and most PCI procedures are performed in large-volume centers, except in Japan. CONCLUSIONS: Comparison of the AMI databases suggest there is a relationship between the primary PCI rate and annual PCI caseload in each country. It is interesting that in Japan even low-volume PCI hospitals have comparable numbers of primary PCI cases.
Angioplasty, Balloon, Coronary↗
[Cardiac rupture caused by myocardial infarction in the diagonal branch area: evaluation by cardiac multislice computed tomography: a case report].
A 75-year-old woman was admitted to the emergency room because of hypotension and loss of consciousness induced by cardiac tamponade. Electrocardiography revealed ST elevation and laboratory data showed elevation of serum creatine kinase and troponin I. The patient was referred to the cardiology department 5 days later. Cardiac catheterization revealed ventricular aneurysm in the anterior wall, significant stenosis (75%) in the left anterior descending coronary artery and subtotal stenosis (99%) in the diagonal branch. Cardiac multislice computed tomography suggested that the ventricular pseudoaneurysm was probably due to cardiac rupture caused by myocardial infarction in the diagonal area. Subsequently, aneurysmectomy and coronary artery bypass graft surgery were performed. Cardiac multislice computed tomography is useful for evaluating coronary artery and cardiac rupture.
Aged↗
Identification of R(-)-isomer of efonidipine as a selective blocker of T-type Ca2+ channels.
Efonidipine, a derivative of dihydropyridine Ca(2+) antagonist, is known to block both L- and T-type Ca(2+) channels. It remains to be clarified, however, whether efonidipine affects other voltage-dependent Ca(2+) channel subtypes such as N-, P/Q- and R-types, and whether the optical isomers of efonidipine have different selectivities in blocking these Ca(2+) channels, including L- and T-types. To address these issues, the effects of efonidipine and its R(-)- and S(+)-isomers on these Ca(2+) channel subtypes were examined electrophysiologically in the expression systems using Xenopus oocytes and baby hamster kidney cells (BHK tk-ts13). Efonidipine, a mixture of R(-)- and S(+)-isomers, exerted blocking actions on L- and T-types, but no effects on N-, P/Q- and R-type Ca(2+) channels. The selective blocking actions on L- and T-type channels were reproduced by the S(+)-efonidipine isomer. By contrast, the R(-)-efonidipine isomer preferentially blocked T-type channels. The blocking actions of efonidipine and its enantiomers were dependent on holding potentials. These findings indicate that the R(-)-isomer of efonidipine is a specific blocker of the T-type Ca(2+) channel.
Animals↗
Improved performance of a new thrombus aspiration catheter: outcomes from in vitro experiments and a case presentation.
Thrombus vacuum catheter (TVAC) is a new thrombus aspiration catheter. The catheter has a beak-shaped distal tip and a shaft with spring support. Based on in vitro tests, these design features showed improved ability to pass through a simulated coronary artery model with a bend and to aspirate gel. TVAC has an outer diameter of 4.5 Fr and is available with a 7 Fr guide. We report a case of acute myocardial infarction that was successfully treated with TVAC after use of other aspiration devices failed in its treatment. Since protection of microcirculation in coronary reperfusion may be essential in acute myocardial infarction, TVAC is a promising device to help achieve this goal.
Catheterization↗
[What aspects are inefficient concerning percutaneous coronary intervention in Japan?: International cost-effectiveness comparisons].
OBJECTIVES: To investigate the outcome-cost relationship of percutaneous coronary intervention (PCI) during 1 year in Japan and other countries. Foreign databases showing similar coronary events to those observed in Japan during the follow-up period were chosen. METHODS: The Japanese multicenter prospective observational cost database (JSIC) was compared to the Stent Restenosis Study (STRESS), a university hospital (DUKE), Arterial Revascularization Therapies Study (ARTS), and the Primary Angioplasty in Myocardial Infarction trial (PAMI). The presence of acute myocardial infarction (AMI), implantation of stents, and number of involved coronary vessels are known to affect the costs of the initial hospitalization and during the follow-up period. The JSIC database was subdivided according to those factors and the initial hospitalization expenses and follow-up costs was compared. RESULTS: All foreign databases showed similar outcomes for coronary events (deaths or repeat PCI or bypass surgery)compared to the JSIC during the 1 year follow-up period. The cumulative costs for the non-AMI group in the JSIC, STRESS, DUKE, and ARTS were 23.1, 11.3, 22.2, and 10.7 thousand dollars, respectively, and for the AMI group were 27.6 and 20.1 thousand dollars in the JSIC and PAMI, respectively. Balloon catheter costs of initial hospitalization expenses accounted for 50% in JSIC, 23% in STRESS, 31% in DUKE, and 16% in PAMI, but the mean numbers of balloons and stents used per patient were similar. CONCLUSIONS: Costs for PCI were higher in Japan than in most other countries. The difference derived mainly from the higher costs of catheters, not from the longer hospital stay in Japan.
Angioplasty, Balloon, Coronary↗
Health-related quality of life of Japanese patients with chronic heart failure: assessment using the Medical Outcome Study Short Form 36.
Chronic heart failure is characterized by impaired cardiac function, but the relationship between clinical indices and subjective perception is not clear. This study was undertaken to investigate the relationship between cardiac function, exercise capacity and clinical classification, and the health-related quality of life (HRQOL) in 91 outpatients with an left ventricular ejection fraction (LVEF) less than 40%. Exercise capacity was evaluated by the Specific Activity Scale, and HRQOL by the Medical Outcome Study Short Form 36. Exercise capacity and the cardiothoracic ratio were correlated with the HRQOL related to physical functioning, although the correlation between exercise capacity and mental health was not significant. LVEF was not related to HRQOL. Factor analysis revealed (1) LVEF was independent of physical functioning; (2) physical function and exercise capacity comprise a factor reflecting physical HRQOL; and (3) socio-emotional functioning is the third factor independent of LVEF and physical function. Physical and socio-mental HRQOL measurement included information independent of the widely used clinical indices such as LVEF and New York Heart Association classification. The evaluation of HRQOL should be included in the assessment of patient status.
Aged↗
Actual state of radiation exposure during coronary angioplasty: a multicenter study in the nationwide database for cost analysis of percutaneous transluminal coronary angioplasty in Japan.
Percutaneous coronary intervention (PCI) has been associated with excessive radiation exposure, so the present study was designed to investigate the determinants of fluoroscopic time during PCI among characteristics inherent to the patient, procedure and hospital in 388 consecutive patients between November 1996 and March 1999 in 11 hospitals included in the Nationwide Database for Cost Analysis of percutaneous transluminal coronary angioplasty in Japan. Fluoroscopic time, which reflects radiation exposure, was used as the dependent variable in a multiple linear regression analysis. The mean fluoroscopic time was 27+/-15 min. The negative value of partial correlation of the hospital code (r=-0.374) and acute myocardial infarction (-0.163) indicated that these were explanatory variables that decreased fluoroscopic time. The positive value of the number of intraaortic balloon pump catheters (r=0.144), the number of balloons (r=0.304) and hospital stay (r=0.147) indicated these were explanatory variables that increased fluoroscopic time. The absolute value of r, (r=0.374), of the hospital code was the highest. In the final R(2) (=0.304) of the model, which is the partial R-square that determined the dependent variable, the hospital code showed the highest value. In conclusion, there was an inter-hospital difference in fluoroscopic time. Although the hospital code was found to be the most powerful determinant of fluoroscopic time, the R(2) (=0.304) of the model showed so lower value that other hospital characteristics that were not included in the model may influence the fluoroscopic time.
Aged↗
Early detection of doxorubicin-induced myocardial damage by ultrasound tissue characterization with integrated backscatter.
Doxorubicin (DXR) is one of the most effective antineoplastic agents, but its use is limited by its myocardial toxicity. Myocardial injury reduces the cyclic variation of integrated backscatter (CV-IBS) and so the present study was designed to investigate whether CV-IBS can be used to detect the early phase of myocardial damage in patients receiving DXR. Thirty-four subjects constituted the study population, none of whom showed clinically evident heart failure. CV-IBS was obtained for both the interventricular septum and the left ventricular posterior wall in the parasternal short-axis view. Standard echographic measures of left ventricular function were also made. Subjects without DXR exposure or evident cardiac diseases served as controls. The total dose of DXR administered per patient was 339+/-164 mg/m2 (range: 95-680 mg/m2). Conventional echographic parameters, including left ventricular wall thickness, dimensions, fractional shortening, and ejection fraction, showed no significant differences between the 2 groups. In contrast, CV-IBS was significantly decreased in the DXR group compared with the control group (septum: 4.7+/-1.7 vs 7.2+/-1.9 dB, p<0.0001; posterior wall: 6.7 +/-2.2 vs 8.0+/-1.6 dB, p<0.05). CV-IBS can be used as an early indicator of DXR-induced myocardial damage in patients demonstrating normal left ventricular systolic function.
Adult↗
[Diagnosis of stable effort angina pectoris].
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Angina Pectoris↗