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Takashi Akasaka - One of the best experts on this subject based on the ideXlab platform.

  • Mechanisms of impaired Coronary Flow Reserve in patients with aortic stenosis: transthoracic Doppler echocardiographic study
    Journal of Cardiology, 2004
    Co-Authors: Teruyoshi Kume, Takashi Akasaka, Takahiro Kawamoto, Nozomi Watanabe, Hidetoshi Yoshitani, Maki Akiyama, Yuji Koyama, Yoji Neishi, Nozomi Wada, Katsuya Yoshida
    Abstract:

    Development of left ventricular hypertrophy in severe aortic stenosis is associated with Coronary microcirculatory dysfunction, as demonstrated by impaired Coronary Flow Reserve. Recently, Coronary Flow Reserve can be assessed noninvasively by transthoracic Doppler echocardiography (TTDE). This study assessed the relationship between Coronary Flow Reserve obtained by TTDE and the hemodynamic parameters and left ventricular mass index in patients with aortic stenosis. Consecutive 29 patients (15 men, 14 women, mean age 72 +/- 11 years) with isolated mild to severe aortic stenosis were studied using TTDE to assess Coronary Flow Reserve. Peak transvalvular pressure gradient across the aortic valve (peak AVG) and aortic valve area were measured by TTDE. Left ventricular mass index was measured by echocardiography. There were significant correlations between Coronary Flow Reserve and peak AVG (r = -0.570, p = 0.001), left ventricular mass index (r = -0.620, p < 0.001), aortic valve area (r = 0.740, p < 0.001), and left ventricular rate pressure product (r = -0.660, p < 0.001). Multiple regression analysis showed that aortic valve area and peak AVG were independent factors for Coronary Flow Reserve (p < 0.001, p = 0.048). Impairment of Coronary Flow Reserve in patients with aortic stenosis is related to aortic valve area and peak AVG, rather than the degree of left ventricular hypertrophy.

  • Assessment of Coronary Flow Reserve by Coronary pressure measurement ; comparison with Flow- or velocity-derived Coronary Flow Reserve
    Journal of the American College of Cardiology, 2003
    Co-Authors: Takashi Akasaka, Nozomi Watanabe, Maki Akiyama, Yuji Koyama, Yoji Neishi, Tsutomu Takagi, Atsushi Yamamuro, Norio Kamiyama, Evgeny Shalman, Chen Barak
    Abstract:

    Abstract Objectives This study sought to assess the reliability of pressure-derived Coronary Flow Reserve (CFR) compared with Flow- or velocity-derived CFR. Background Coronary Flow Reserve has been reported to have important clinical implications for the evaluation and treatment of Coronary artery disease. Methods Using a pressure guide wire, Coronary pressure distal to the stenosis was measured at rest and during hyperemia in seven dogs with various degrees of stenosis and in 30 patients with angina (29 and 34 stenoses in total, respectively). Pressure at the tip of the guiding catheter was also recorded with a fluid-filled transducer system. Pressure-derived CFR was calculated by the square root of the pressure gradient across the stenosis (ΔP) during hyperemia divided by ΔP at rest, using a proprietary software system. At the same time, Coronary Flow was monitored proximal to the stenosis with a Flow meter in the experimental dogs, and Coronary Flow velocity distal to the stenosis was assessed using a Doppler guide wire in patients with angina. Flow-derived (or velocity-derived) CFR was compared with pressure-derived CFR. Results Except for one stenosis that showed no ΔP at rest, a significant correlation was obtained between pressure- and Flow-derived CFR in the animal study (y = 1.05x − 0.03, r = 0.92, p = 0.0001). A significant correlation was also seen between pressure- and velocity-derived CFR in the human study, except in three stenoses with no resting ΔP (y = 0.70x + 0.37, r = 0.85, p = 0.0001). Conclusions Similar to Flow (or velocity) measurement, CFR can be assessed by pressure measurement, except in stenoses with minor resting ΔP.

  • Noninvasive estimation of Coronary Flow Reserve by transthoracic Doppler echocardiography with a high-frequency transducer.
    Journal of Cardiology, 2001
    Co-Authors: Takeshi Hozumi, Takashi Akasaka, Kiyoshi Yoshida, Junichi Yoshikawa
    Abstract:

    Recent technological advances in transthoracic Doppler echocardiography (TTDE) provide visualization of the Coronary blood Flow signal and noninvasive analysis of Coronary Flow Reserve with a high frequency transducer. Coronary Flow velocity and Coronary Flow Reserve measured by TTDE were compared with those measured by a Doppler guide wire. Values of mean Coronary Flow velocity and Coronary Flow Reserve measured by TTDE were closely correlated with values measured by the invasive Doppler guide wire (r = 0.97, y = 0.94x + 0.40; r = 0.94, y = 0.95x + 0.21, respectively). This noninvasive technique was applied to patients who underwent Coronary angiography to evaluate Coronary artery disease. There was a significant difference in Coronary Flow Reserve measured by TTDE between patients with and without significant left anterior descending Coronary artery stenosis (% diameter stenosis > 70%) (1.5 +/- 0.2 vs 2.6 +/- 0.4, p < 0.001). Coronary Flow Reserve < 2.0 obtained by TTDE had a high sensitivity (92%) and a high specificity (86%) for the presence of significant left anterior descending Coronary artery stenosis. TTDE with a high-frequency transducer can be applied to noninvasive estimation of Coronary Flow Reserve in the clinical setting, and is useful in noninvasive diagnosis of significant Coronary stenosis in patients with Coronary artery disease.

  • Retinopathy Identifies Marked Restriction of Coronary Flow Reserve in Patients With Diabetes Mellitus
    Journal of the American College of Cardiology, 1997
    Co-Authors: Takashi Akasaka, Takeshi Hozumi, Takahiro Kawamoto, Kiyoshi Yoshida, Tsutomu Takagi, Shuichiro Kaji, Shigefumi Morioka, Junichi Yoshikawa
    Abstract:

    Objectives. This study sought to assess the differences in Coronary Flow Reserve in patients with and without diabetic retinopathy. Background. Microvascular abnormalities throughout the body and impairment of Coronary Flow Reserve have been described in patients with diabetes mellitus. However, the relation between diabetic retinopathy and Coronary microvascular disease has not been investigated. Methods. The study included 29 patients with diabetes mellitus (18 with and 11 without diabetic retinopathy) and 15 control patients with chest pain and normal Coronary arteries. Diabetic retinopathy was nonproliferative in all 18 patients with this disorder (8 had background, 10 preproliferative retinopathy). Five minutes after injection of 3 mg of isosorbide dinitrate, phasic Flow velocities were recorded in the proximal segment of the angiographically normal left anterior descending Coronary artery at rest and during hyperemia (0.14 mg/kg body weight per min of adenosine infused intravenously) using a 0.014-in. 15-MHz Doppler guide wire. Coronary blood Flow was calculated, and Coronary Flow Reserve was obtained from the hyperemic/baseline Flow ratio. Results. Coronary blood Flow was significantly lower during hyperemia ([mean ± SD] 107 ± 23 and 116 ± 18 vs. 136 ± 17 ml/min, respectively) and higher at baseline (58 ± 16 and 45 ± 12 vs. 37 ± 10 ml/min, respectively) in diabetic patients with and without retinopathy than in control subjects (p < 0.05 for both diabetic groups). As a result, Coronary Flow Reserve in both groups of diabetic patients was significantly lower than in control patients (1.9 ± 0.4 and 2.8 ± 0.3 vs. 3.3 ± 0.4, respectively, p < 0.01 for both diabetic groups), and its reduction was greater in patients with than without retinopathy (p < 0.01). Furthermore, in patients with diabetic retinopathy, maximal hyperemic Coronary Flow (102 ± 11 vs. 114 ± 16 ml/min, p < 0.05) and Flow Reserve (1.6 ± 0.2 vs. 2.3 ± 0.2, p < 0.01) were significantly lower in those with preproliferative than background retinopathy. Conclusions. Coronary Flow Reserve is significantly restricted in patients with diabetes mellitus, and its reduction is more marked in those with diabetic retinopathy, especially in advanced retinopathy. Thus, diabetic retinopathy should identify marked restriction of Coronary Flow Reserve in patients with diabetes mellitus.

  • Effects of infarcted myocardium on Coronary Flow Reserve: a study by transesophageal Doppler echocardiography
    Journal of Cardiology, 1994
    Co-Authors: Nobuhiro Tanaka, Takeshi Hozumi, Junichi Yoshikawa, Ken Yoshida, Takashi Akasaka, Masahiro Shakudo, Miyake S, Ibukiyama C
    Abstract:

    Myocardial disorder or microvascular disorder can cause impairment of Coronary Flow Reserve in patients without epicardial Coronary artery stenosis. This study investigated whether infarcted myocardium influences the Coronary Flow Reserve using transesophageal echocardiography. The Coronary Flow Reserve was examined in 15 patients with anterior myocardial infarction without residual Coronary artery stenosis in the chronic phase. The patients underwent 201Tl scintigraphy and were classified into two groups. Group I included six patients without salvaged myocardium and group II included nine patients with salvaged myocardium. The Coronary blood Flow velocity at the proximal part of the left anterior descending Coronary artery (LAD) was evaluated by transesophageal echocardiography before and after dipyridamole administration (0.56 mg/kg/4 min). The ratios of the diastolic peak and mean velocities at hyperemia versus baseline were used as indices of Coronary Flow Reserve (P-CFR and M-CFR, respectively). P-CFR and M-CFR were 1.7 +/- 0.3 and 1.5 +/- 0.4 in group I, and 2.9 +/- 0.5 and 2.7 +/- 0.6 in group II, respectively. Control subjects (n = 7) had P-CFR and M-CFR of 3.8 +/- 0.9 and 3.9 +/- 1.7, respectively. Coronary Flow Reserve decreased in patients with myocardial infarction, especially in patients without salvaged myocardium in the infarcted area. Infarcted myocardium has an important influence on Coronary Flow Reserve, and transesophageal echocardiography is useful for evaluating Coronary Flow Reserve.

Miklós Csanády - One of the best experts on this subject based on the ideXlab platform.

  • Echocardiographic Evaluation and Clinical Implications of Aortic Stiffness and Coronary Flow Reserve and their Relation
    Clinical Cardiology, 2008
    Co-Authors: Attila Nemes, Tamás Forster, Marcel L. Geleijnse, Osama Ibrahim Ibrahim Soliman, Folkert J. Ten Cate, Miklós Csanády
    Abstract:

    The normal human aorta is not a stiff tube, but is characterized by elastic properties with a buffering Windkessel function. Aortic stiffening may cause an increase in aortic pulse pressure, left ventricular (LV) load, and ultimately left ventricular hypertrophy. This, together with the decreased diastolic transmyocardial pressure gradient, interacts with Coronary Flow and Flow Reserve. In recent studies, significant correlations between Coronary Flow Reserve and aortic stiffness have been demonstrated in different patient populations. The aim of this review is to describe the current echocardiographic modalities to measure aortic stiffness and Coronary Flow Reserve, and to overview knowledge about the relationship between aortic stiffness and Coronary Flow Reserve.

  • Coronary Flow Reserve, insulin resistance and blood pressure response to standing in patients with normoglycaemia: Is there a relationship?
    Diabetic Medicine, 2005
    Co-Authors: Attila Nemes, Tamás Forster, C. Lengyel, Tamás Várkonyi, R Takács, István Nagy, Péter Kempler, János Lonovics, Miklós Csanády
    Abstract:

    Aims  To establish the relationships between Coronary Flow Reserve, cardiovascular autonomic function, and insulin resistance characterized by the homeostasis model assessment insulin resistance score in patients with normal carbohydrate metabolism according to the World Health Organization (WHO) and American Diabetes Association (ADA) criteria, and with morphologically normal epicardial Coronary arteries. Methods  Twenty-five patients [12 women and 13 men, mean (sd) age: 53 ± 11 years] with normal Coronary angiography were enrolled into the study. Coronary Flow Reserve was measured during stress transoesophageal echocardiography. Autonomic dysfunction was assessed by means of five standard cardiovascular reflex tests. The fasting serum glucose and insulin levels were determined and the homeostasis assessment model insulin resistance score was calculated. Results  In patients with normal carbohydrate metabolism, negative correlations were observed between the Coronary Flow Reserve and both the serum insulin level (r = −0.445, P = 0.026) and the homeostasis assessment model insulin resistance score (r = −0.449, P = 0.024). The systolic blood pressure response to standing also correlated with the Coronary Flow Reserve (r = −0.519, P = 0.011). The heart rate response to deep breathing, the Valsalva ratio, the 30/15 ratio and the sustained handgrip test results were not correlated with the Coronary Flow Reserve. Conclusions  Our data suggest the possible role of insulin resistance and early sympathetic nerve dysfunction in the development of decreased Coronary Flow Reserve in patients without diabetes mellitus or impaired glucose tolerance.

  • How Can Coronary Flow Reserve Be Altered by Severe Aortic Stenosis
    Echocardiography-a Journal of Cardiovascular Ultrasound and Allied Techniques, 2002
    Co-Authors: Attila Nemes, Tamás Forster, Albert Varga, Andrea Vass, Angela Borthaiser, Attila Pálinkás, Miklós Csanády
    Abstract:

    The Coronary Flow Reserve, a well-known characteristic of the distensibility of the Coronary arteries, can be measured by means of dipyridamole stress transesophageal echocardiography. This study compared the Coronary Flow Reserve in patients with normal Coronary arteries with aortic stenosis (Group 1), in patients with normal Coronary arteries without aortic stenosis (Group 2), and in patients with significant left anterior descending Coronary artery disease (Group 3). Patients and Methods: Groups 1 and 2 were comprised of 21 patients each, while Group 3 was comprised of 37 patients. Transesophageal stress echocardiography was carried out according to a standard protocol, with a vasodilator stimulus of dipyridamole in a dose of 0.56 mg/kg over 4 minutes. The Coronary Flow Reserve was calculated as the ratio of posthyperemic to basal peak (CFR) and mean (mean CFR) diastolic Flow velocities. Results: The left ventricular mass and left ventricular mass index were significantly higher in Group 1 than in Groups 2 and 3. The Coronary Flow Reserve and the posthyperemic mean diastolic Flow velocities were significantly lower, while the resting mean diastolic Flow velocities were significantly higher in Groups 1 and 3 than in Group 2. Conclusions: In patients with aortic stenosis and a normal Coronary angiogram, the Coronary Flow Reserve is significantly lower, similarly as in the case of significant left anterior descending Coronary artery disease. In severe aortic stenosis with left ventricular hypertrophy, stress transesophageal echocardiography is unable to distinguish between the drop in Coronary Flow Reserve caused by a vascular or a myocardial component, and therefore, not suitable for the selection of patients with significant Coronary artery disease, even in cases of left anterior descending Coronary artery disease.

  • The clinical value of Coronary Flow Reserve in ischemic heart disease as measured by dipyridamole stress transesophageal echocardiography
    Orvosi Hetilap, 2000
    Co-Authors: Attila Nemes, Tamás Forster, Andrea Vass, Attila Pálinkás, A. Borthaiser, Imre Ungi, Attila Thury, E. Litvai, M. Nádaskay, Miklós Csanády
    Abstract:

    The relationship between Coronary Flow Reserve and the result of coronarography was examined. 152 patients were investigated by stress transoesophageal echocardiography and Coronary angiography. The value of Coronary Flow Reserve was significantly lower in cases of significant Coronary stenosis than in those patients who had a normal coronarography (in patients with left anterior descending Coronary artery stenosis: 1.77 +/- 0.47 vs in cases with normal Coronary angiogram: 3.19 +/- 1.15). There was no difference in the value of CFR in those cases where not only LAD stenosis but CX or RC stenosis was also found. The value of Coronary Flow Reserve was significantly higher in RC or CX patients than that of LAD patients. In patients with positive stress and negative coronarography (X syndrome) the Coronary Flow Reserve was 1.23 +/- 0.2, which value was significantly lower as compared to patients with significant Coronary stenosis.

Attila Nemes - One of the best experts on this subject based on the ideXlab platform.

  • Echocardiographic Evaluation and Clinical Implications of Aortic Stiffness and Coronary Flow Reserve and their Relation
    Clinical Cardiology, 2008
    Co-Authors: Attila Nemes, Tamás Forster, Marcel L. Geleijnse, Osama Ibrahim Ibrahim Soliman, Folkert J. Ten Cate, Miklós Csanády
    Abstract:

    The normal human aorta is not a stiff tube, but is characterized by elastic properties with a buffering Windkessel function. Aortic stiffening may cause an increase in aortic pulse pressure, left ventricular (LV) load, and ultimately left ventricular hypertrophy. This, together with the decreased diastolic transmyocardial pressure gradient, interacts with Coronary Flow and Flow Reserve. In recent studies, significant correlations between Coronary Flow Reserve and aortic stiffness have been demonstrated in different patient populations. The aim of this review is to describe the current echocardiographic modalities to measure aortic stiffness and Coronary Flow Reserve, and to overview knowledge about the relationship between aortic stiffness and Coronary Flow Reserve.

  • Prognostic role of combination of Coronary Flow Reserve with aortic distensibility indices
    European Heart Journal, 2006
    Co-Authors: Attila Nemes, Marcel L. Geleijnse, Osama Ibrahim Ibrahim Soliman, Folkert J. Ten Cate
    Abstract:

    We read with great interest the study of Rigo et al. 1 entitled ‘The prognostic impact of Coronary Flow Reserve assessed by Doppler echocardiography in non-ischaemic dilated cardiomyopathy’. This intriguing echocardiographic study found that Doppler echocardiographic-derived reduced Coronary Flow Reserve (CFR) during vasodilator stress is an independent prognostic marker of bad prognosis in dilated cardiomyopathy (DCM). However, we feel that a …

  • Coronary Flow Reserve, insulin resistance and blood pressure response to standing in patients with normoglycaemia: Is there a relationship?
    Diabetic Medicine, 2005
    Co-Authors: Attila Nemes, Tamás Forster, C. Lengyel, Tamás Várkonyi, R Takács, István Nagy, Péter Kempler, János Lonovics, Miklós Csanády
    Abstract:

    Aims  To establish the relationships between Coronary Flow Reserve, cardiovascular autonomic function, and insulin resistance characterized by the homeostasis model assessment insulin resistance score in patients with normal carbohydrate metabolism according to the World Health Organization (WHO) and American Diabetes Association (ADA) criteria, and with morphologically normal epicardial Coronary arteries. Methods  Twenty-five patients [12 women and 13 men, mean (sd) age: 53 ± 11 years] with normal Coronary angiography were enrolled into the study. Coronary Flow Reserve was measured during stress transoesophageal echocardiography. Autonomic dysfunction was assessed by means of five standard cardiovascular reflex tests. The fasting serum glucose and insulin levels were determined and the homeostasis assessment model insulin resistance score was calculated. Results  In patients with normal carbohydrate metabolism, negative correlations were observed between the Coronary Flow Reserve and both the serum insulin level (r = −0.445, P = 0.026) and the homeostasis assessment model insulin resistance score (r = −0.449, P = 0.024). The systolic blood pressure response to standing also correlated with the Coronary Flow Reserve (r = −0.519, P = 0.011). The heart rate response to deep breathing, the Valsalva ratio, the 30/15 ratio and the sustained handgrip test results were not correlated with the Coronary Flow Reserve. Conclusions  Our data suggest the possible role of insulin resistance and early sympathetic nerve dysfunction in the development of decreased Coronary Flow Reserve in patients without diabetes mellitus or impaired glucose tolerance.

  • How Can Coronary Flow Reserve Be Altered by Severe Aortic Stenosis
    Echocardiography-a Journal of Cardiovascular Ultrasound and Allied Techniques, 2002
    Co-Authors: Attila Nemes, Tamás Forster, Albert Varga, Andrea Vass, Angela Borthaiser, Attila Pálinkás, Miklós Csanády
    Abstract:

    The Coronary Flow Reserve, a well-known characteristic of the distensibility of the Coronary arteries, can be measured by means of dipyridamole stress transesophageal echocardiography. This study compared the Coronary Flow Reserve in patients with normal Coronary arteries with aortic stenosis (Group 1), in patients with normal Coronary arteries without aortic stenosis (Group 2), and in patients with significant left anterior descending Coronary artery disease (Group 3). Patients and Methods: Groups 1 and 2 were comprised of 21 patients each, while Group 3 was comprised of 37 patients. Transesophageal stress echocardiography was carried out according to a standard protocol, with a vasodilator stimulus of dipyridamole in a dose of 0.56 mg/kg over 4 minutes. The Coronary Flow Reserve was calculated as the ratio of posthyperemic to basal peak (CFR) and mean (mean CFR) diastolic Flow velocities. Results: The left ventricular mass and left ventricular mass index were significantly higher in Group 1 than in Groups 2 and 3. The Coronary Flow Reserve and the posthyperemic mean diastolic Flow velocities were significantly lower, while the resting mean diastolic Flow velocities were significantly higher in Groups 1 and 3 than in Group 2. Conclusions: In patients with aortic stenosis and a normal Coronary angiogram, the Coronary Flow Reserve is significantly lower, similarly as in the case of significant left anterior descending Coronary artery disease. In severe aortic stenosis with left ventricular hypertrophy, stress transesophageal echocardiography is unable to distinguish between the drop in Coronary Flow Reserve caused by a vascular or a myocardial component, and therefore, not suitable for the selection of patients with significant Coronary artery disease, even in cases of left anterior descending Coronary artery disease.

  • The clinical value of Coronary Flow Reserve in ischemic heart disease as measured by dipyridamole stress transesophageal echocardiography
    Orvosi Hetilap, 2000
    Co-Authors: Attila Nemes, Tamás Forster, Andrea Vass, Attila Pálinkás, A. Borthaiser, Imre Ungi, Attila Thury, E. Litvai, M. Nádaskay, Miklós Csanády
    Abstract:

    The relationship between Coronary Flow Reserve and the result of coronarography was examined. 152 patients were investigated by stress transoesophageal echocardiography and Coronary angiography. The value of Coronary Flow Reserve was significantly lower in cases of significant Coronary stenosis than in those patients who had a normal coronarography (in patients with left anterior descending Coronary artery stenosis: 1.77 +/- 0.47 vs in cases with normal Coronary angiogram: 3.19 +/- 1.15). There was no difference in the value of CFR in those cases where not only LAD stenosis but CX or RC stenosis was also found. The value of Coronary Flow Reserve was significantly higher in RC or CX patients than that of LAD patients. In patients with positive stress and negative coronarography (X syndrome) the Coronary Flow Reserve was 1.23 +/- 0.2, which value was significantly lower as compared to patients with significant Coronary stenosis.

Eugenio Picano - One of the best experts on this subject based on the ideXlab platform.

  • additional prognostic value of Coronary Flow Reserve in diabetic and nondiabetic patients with negative dipyridamole stress echocardiography by wall motion criteria
    Journal of the American College of Cardiology, 2007
    Co-Authors: Lauro Cortigiani, Fausto Rigo, Sonia Gherardi, Maurizio Galderisi, Rosa Sicari, Francesco Bovenzi, Eugenio Picano
    Abstract:

    Objectives The aim of this prospective, multicenter, observational study was to compare the prognostic value of Doppler echocardiographic-derived Coronary Flow Reserve (CFR) in diabetic and nondiabetic patients with known or suspected Coronary artery disease and negative dipyridamole stress echocardiography. Background The prognostic value of CFR in diabetic patients with negative stress echocardiography remains unknown. Methods The study group consisted of 1,130 patients (207 diabetics) with known (n = 418) or suspected (n = 712) Coronary artery disease and negative stress echocardiography by wall motion criteria. All underwent dipyridamole (up to 0.84 mg/kg over 6 min) echocardiography with CFR evaluation of left anterior descending artery by Doppler. A value of CFR ≤2.0 was considered abnormal. Results Coronary Flow Reserve was abnormal in 309 (27%) patients. During a median follow-up of 16 months, 98 events (8 deaths, 24 ST-segment elevation myocardial infarctions, and 66 non–ST-segment elevation myocardial infarctions) occurred. In addition, 101 patients underwent revascularization and were censored. Multivariable prognostic indicators were abnormal CFR (p Conclusions Coronary Flow Reserve provides independent prognostic information in diabetic and nondiabetic patients with known or suspected Coronary artery disease and negative dipyridamole stress echocardiography. In particular, a normal CFR off therapy is associated with better and similar survival in the 2 populations.

Martijn A. Van Lavieren - One of the best experts on this subject based on the ideXlab platform.