The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Morton J Kern - One of the best experts on this subject based on the ideXlab platform.
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effects of caffeine and theophylline on coronary Hyperemia induced by adenosine or dipyridamole
Catheterization and Cardiovascular Interventions, 2009Co-Authors: Jonathan Salcedo, Morton J KernAbstract:Objectives: The aims of this review are to examine the biochemical features of theophylline, caffeine, adenosine, and dipyridamole, their effects on coronary Hyperemia, and to make recommendations on performing hyperemic lesion assessment after taking caffeine or theophylline. Background: It is commonly thought that caffeine and theophylline interfere with adenosine and dipyridamole induced coronary Hyperemia, thus frequently delaying scheduled assessments after inadvertent consumption. However, a limited amount of studies address the interactions of these substances thus leaving no clear consensus on when to delay coronary assessment after their intake. Methods: For biochemical information on each substance, online and textbook references were utilized. For studies on the interactions of the substances with coronary Hyperemia, broad search terms such as “caffeine AND adenosine” were applied in the major research data bases. Results: A serum caffeine level of 3 to 4 mg/L at the time of an adenosine-Hyperemia study does not affect the ability of perfusion stress imaging to detect coronary artery disease. The interactions of theophylline with adenosine-Hyperemia are less clear while both caffeine and theophylline show significant interaction with dipyridamole-Hyperemia. Conclusions: For dipyridamole-stress myocardial perfusion studies, caffeine products and theophylline medications should be discontinued for 24 hr. For adenosine-stress myocardial perfusion studies, theophylline medications should be discontinued for 12 hr; however, one cup of coffee may be taken up to 1 hr before the test without necessitating a delay or cancellation of the study. These same considerations hold true for patients undergoing cardiac catheterization and intravenous adenosine-induced Hyperemia. © 2009 Wiley-Liss, Inc.
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fallacy of thoracic side branch steal from the internal mammary artery analysis of left internal mammary artery coronary flow during thoracic side branch occlusion with pharmacologic and exercise induced Hyperemia
Catheterization and Cardiovascular Interventions, 2004Co-Authors: Osler Jay J Guzon, Karen Klatte, Andrea Moyer, Souheil Khoukaz, Morton J KernAbstract:In some patients, myocardial ischemia after coronary artery bypass graft surgery has been attributed to a coronary steal phenomenon through a thoracic side branch originating from the left internal mammary artery (LIMA), even in the absence of subclavian or LIMA stenosis. To demonstrate that coronary flow through the LIMA is unchanged by occlusion of a LIMA side branch, we examined LIMA coronary flow velocity measurements (0.014″ Doppler flow wire) in three patients at rest, during adenosine Hyperemia, and again during Hyperemia induced by left arm exercise before and again after the balloon occlusion of the thoracic side branch. For the three patients, no significant changes in resting or hyperemic flow were noted due to side-branch occlusion. Before side-branch occlusion, pharmacologic intra-arterial (adenosine) coronary flow reserve (hyperemic-to-basal flow velocity ratio) was 2.6, 1.5, and 3.2 and exercise flow reserve was 2.1, 1.3, and 1.2, respectively. After side-branch occlusion, pharmacologic coronary flow reserve was 2.5, 1.8, and 2.7 with exercise flow reserve of 1.8, 1.1, and 1.3, respectively. Under most ordinary circumstances, thoracic side-branch steal does not exist and that side-branch occlusion does not alter LIMA flow at rest or during pharmacologic or exercise-induced Hyperemia. These data further suggest that a demonstration of the physiologic value of side-branch occlusion should precede surgical or percutaneous interruption of the thoracic artery in such patients. Catheter Cardiovasc Interv 2004;61:20–28. © 2004 Wiley-Liss, Inc.
Nico H J Pijls - One of the best experts on this subject based on the ideXlab platform.
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fractional flow reserve maximum Hyperemia adenosine and regadenoson
Cardiovascular Revascularization Medicine, 2015Co-Authors: Nico H J Pijls, Lokien X Van NunenAbstract:Currently, there is little doubt that interpretation of coronary artery disease and decision making with respect to revascularization based on visualassessmentoftheangiogramisafundamentally flawedapproach. The importance of additional functional testing to assess the hemodynamic severity of a coronary stenosis is undisputable. Over the decades, a number of physiologic indices have emerged to assess the functional significance of coronary artery disease. Of these, fractional flow reserve (FFR) is most commonly used. There is incontrovertible proof now that stenting of ischemic stenoses as indicated by a FFR ≤0.80 generally improvesoutcome, whereasstentingofnon-ischemicstenosisasindicated by a FFR N0.80 offers nobenefit compared to medical treatment and can mostly be avoided [1–6]. To assess the true strength or quality of anything in the world around us—whether in science, engineering, or biology—testing under conditionsof stress is mandatory. In analogy,therefore, the windtunnel for physiologic testing of coronary arteries is maximum Hyperemia. Accurate assessment of FFR can be done only during maximum hyperemic conditions. An interesting analysis of a rather new hyperemic drug, regadenoson, is published in the current issue of Cardiovascular Revascularization Medicine (CRM) [7].
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effect of phentolamine on the hyperemic response to adenosine in patients with microvascular disease
American Journal of Cardiology, 2005Co-Authors: Wilbert Aarnoudse, Maartje Geven, Emanuele Barbato, Keesjoost Botman, Bernard De Bruyne, Nico H J PijlsAbstract:For accurate measurement of the fractional flow reserve (FFR) of the myocardium, the presence of maximum Hyperemia is of paramount importance. It has been suggested that the hyperemic effect of the conventionally used hyperemic stimulus, adenosine, could be submaximal in patients who have microvascular dysfunction and that adding α-blocking agents could augment the hyperemic response in these patients. We studied the effect of the nonselective α-blocking agent phentolamine, which was administered in addition to adenosine after achieving Hyperemia, in patients who had microvascular disease and those who did not. Thirty patients who were referred for percutaneous coronary intervention were selected. Of these 30 patients, 15 had strong indications for microvascular disease and 15 did not. FFR was measured using intracoronary adenosine, intravenous adenosine, and intracoronary papaverine before and after intracoronary administration of the nonselective α blocker phentolamine. In patients who did not have microvascular disease, no differences in hyperemic response to adenosine were noted, whether or not α blockade was given before adenosine administration; FFR levels before and after phentolamine were 0.76 and 0.75, respectively, using intracoronary adenosine (p = 0.10) and 0.75 and 0.74, respectively, using intravenous adenosine (p = 0.20). In contrast, in patients who had microvascular disease, some increase in hyperemic response was observed after administration of phentolamine; FFR levels decreased from 0.74 to 0.70 using intracoronary adenosine (p = 0.003) and from 0.75 to 0.72 using intravenous adenosine (p = 0.04). Although statistically significant, the observed further decrease in microvascular resistance after addition of phentolamine was small and did not affect clinical decision making in any patient. In conclusion, when measuring FFR, routinely adding an α-blocking agent to adenosine does not affect clinical decision making.
Osler Jay J Guzon - One of the best experts on this subject based on the ideXlab platform.
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fallacy of thoracic side branch steal from the internal mammary artery analysis of left internal mammary artery coronary flow during thoracic side branch occlusion with pharmacologic and exercise induced Hyperemia
Catheterization and Cardiovascular Interventions, 2004Co-Authors: Osler Jay J Guzon, Karen Klatte, Andrea Moyer, Souheil Khoukaz, Morton J KernAbstract:In some patients, myocardial ischemia after coronary artery bypass graft surgery has been attributed to a coronary steal phenomenon through a thoracic side branch originating from the left internal mammary artery (LIMA), even in the absence of subclavian or LIMA stenosis. To demonstrate that coronary flow through the LIMA is unchanged by occlusion of a LIMA side branch, we examined LIMA coronary flow velocity measurements (0.014″ Doppler flow wire) in three patients at rest, during adenosine Hyperemia, and again during Hyperemia induced by left arm exercise before and again after the balloon occlusion of the thoracic side branch. For the three patients, no significant changes in resting or hyperemic flow were noted due to side-branch occlusion. Before side-branch occlusion, pharmacologic intra-arterial (adenosine) coronary flow reserve (hyperemic-to-basal flow velocity ratio) was 2.6, 1.5, and 3.2 and exercise flow reserve was 2.1, 1.3, and 1.2, respectively. After side-branch occlusion, pharmacologic coronary flow reserve was 2.5, 1.8, and 2.7 with exercise flow reserve of 1.8, 1.1, and 1.3, respectively. Under most ordinary circumstances, thoracic side-branch steal does not exist and that side-branch occlusion does not alter LIMA flow at rest or during pharmacologic or exercise-induced Hyperemia. These data further suggest that a demonstration of the physiologic value of side-branch occlusion should precede surgical or percutaneous interruption of the thoracic artery in such patients. Catheter Cardiovasc Interv 2004;61:20–28. © 2004 Wiley-Liss, Inc.
Atsuki Fukushima - One of the best experts on this subject based on the ideXlab platform.
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Development of automated conjunctival Hyperemia analysis software.
Cornea, 2020Co-Authors: Tamaki Sumi, Tsuyoshi Yoneda, Ken Fukuda, Yasuhiro Hoshikawa, Masahiko Kobayashi, Masahide Yanagi, Yoshiaki Kiuchi, Kahoko Yasumitsu-lovell, Atsuki FukushimaAbstract:Conjunctival Hyperemia is observed in a variety of ocular inflammatory conditions. The evaluation of Hyperemia is indispensable for the treatment of patients with ocular inflammation. However, the major methods currently available for evaluation are based on nonquantitative and subjective methods. Therefore, we developed novel software to evaluate bulbar Hyperemia quantitatively and objectively. First, we investigated whether the histamine-induced Hyperemia of guinea pigs could be quantified by image analysis. Bulbar conjunctival images were taken by means of a digital camera, followed by the binarization of the images and the selection of regions of interest (ROIs) for evaluation. The ROIs were evaluated by counting the number of absolute pixel values. Pixel values peaked significantly 1 minute after histamine challenge was performed and were still increased after 5 minutes. Second, we applied the same method to antigen (ovalbumin)-induced Hyperemia of sensitized guinea pigs, acquiring similar results except for the substantial upregulation in the first 5 minutes after challenge. Finally, we analyzed human bulbar Hyperemia using the new software we developed especially for human usage. The new software allows the automatic calculation of pixel values once the ROIs have been selected. In our clinical trials, the percentage of blood vessel coverage of ROIs was significantly higher in the images of Hyperemia caused by allergic conjunctival diseases and Hyperemia induced by Bimatoprost, compared with those of healthy volunteers. We propose that this newly developed automated Hyperemia analysis software will be an objective clinical tool for the evaluation of ocular Hyperemia.
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Hyperemia Analysis Software for Assessment of Conjunctival Hyperemia Severity
Current Eye Research, 2018Co-Authors: Tsuyoshi Yoneda, Tamaki Sumi, Yasuhiro Hoshikawa, Masahiko Kobayashi, Atsuki FukushimaAbstract:ABSTRACTPurpose: We developed a Hyperemia analysis software, which can quantitatively assess the degree of conjunctival Hyperemia, and evaluated the reproducibility and reliability of its percent c...
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Development of automated conjunctival Hyperemia analysis software.
Cornea, 2013Co-Authors: Tamaki Sumi, Tsuyoshi Yoneda, Ken Fukuda, Yasuhiro Hoshikawa, Masahiko Kobayashi, Masahide Yanagi, Yoshiaki Kiuchi, Kahoko Yasumitsu-lovell, Atsuki FukushimaAbstract:Abstract:Conjunctival Hyperemia is observed in a variety of ocular inflammatory conditions. The evaluation of Hyperemia is indispensable for the treatment of patients with ocular inflammation. However, the major methods currently available for evaluation are based on nonquantitative and subjective m
Bernard De Bruyne - One of the best experts on this subject based on the ideXlab platform.
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intracoronary adenosine dose response relationship with Hyperemia
Jacc-cardiovascular Interventions, 2015Co-Authors: Julien Adjedj, Nils P Johnson, Emanuele Barbato, Gabor G Toth, Mariano Pellicano, Angela Ferrara, Vincent Flore, Giuseppe Di Gioia, Olivier Muller, Bernard De BruyneAbstract:Abstract Objectives The present study sought to establish the dosage of intracoronary (IC) adenosine associated with minimal side effects and above which no further increase in flow can be expected. Background Despite the widespread adoption of IC adenosine in clinical practice, no wide-ranging, dose-response study has been conducted. A recurring debate still exists regarding its optimal dose. Methods In 30 patients, Doppler-derived flow velocity measurements were obtained in 10 right coronary arteries (RCAs) and 20 left coronary arteries (LCAs) free of stenoses >20% in diameter. Flow velocity was measured at baseline and after 8 ml bolus administrations of arterial blood, saline, contrast medium, and 9 escalating doses of adenosine (4 to 500 μg). The hyperemic value was expressed in percent of the maximum flow velocity reached in a given artery (Q/Q max , %). Results Q/Q max did not increase significantly beyond dosages of 60 μg for the RCA and 160 μg for LCA. Heart rate did not change, whereas mean arterial blood pressure decreased by a maximum of 7% (p Conclusions This wide-ranging, dose-response study indicates that an IC adenosine bolus injection of 100 μg in the RCA and 200 μg in the LCA induces maximum Hyperemia while being associated with minimal side effects.
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effect of phentolamine on the hyperemic response to adenosine in patients with microvascular disease
American Journal of Cardiology, 2005Co-Authors: Wilbert Aarnoudse, Maartje Geven, Emanuele Barbato, Keesjoost Botman, Bernard De Bruyne, Nico H J PijlsAbstract:For accurate measurement of the fractional flow reserve (FFR) of the myocardium, the presence of maximum Hyperemia is of paramount importance. It has been suggested that the hyperemic effect of the conventionally used hyperemic stimulus, adenosine, could be submaximal in patients who have microvascular dysfunction and that adding α-blocking agents could augment the hyperemic response in these patients. We studied the effect of the nonselective α-blocking agent phentolamine, which was administered in addition to adenosine after achieving Hyperemia, in patients who had microvascular disease and those who did not. Thirty patients who were referred for percutaneous coronary intervention were selected. Of these 30 patients, 15 had strong indications for microvascular disease and 15 did not. FFR was measured using intracoronary adenosine, intravenous adenosine, and intracoronary papaverine before and after intracoronary administration of the nonselective α blocker phentolamine. In patients who did not have microvascular disease, no differences in hyperemic response to adenosine were noted, whether or not α blockade was given before adenosine administration; FFR levels before and after phentolamine were 0.76 and 0.75, respectively, using intracoronary adenosine (p = 0.10) and 0.75 and 0.74, respectively, using intravenous adenosine (p = 0.20). In contrast, in patients who had microvascular disease, some increase in hyperemic response was observed after administration of phentolamine; FFR levels decreased from 0.74 to 0.70 using intracoronary adenosine (p = 0.003) and from 0.75 to 0.72 using intravenous adenosine (p = 0.04). Although statistically significant, the observed further decrease in microvascular resistance after addition of phentolamine was small and did not affect clinical decision making in any patient. In conclusion, when measuring FFR, routinely adding an α-blocking agent to adenosine does not affect clinical decision making.
