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Flow Velocity Reserve (flow + velocity_reserve)

Distribution by Scientific Domains
Medical Sciences100%

Kinds of Flow Velocity Reserve

  • coronary flow velocity reserve
    		•

    Selected Abstracts

    Noninvasive Assessment of Significant Right Coronary Artery Stenosis Based on Coronary Flow Velocity Reserve in the Right Coronary Artery by Transthoracic Doppler Echocardiography

    ECHOCARDIOGRAPHY, Issue 6 2003
    M.D., Yoshiki Ueno
    Background: Coronary flow velocity reserve (CFVR) measured by transthoracic Doppler echocardiography (TTDE) has been reported to be useful for the noninvasive assessment of coronary stenosis in the left anterior descending artery. However, the measurement of CFVR in the right coronary artery by TTDE has not yet been validated in a clinical study. Objective: The aim of this study was to evaluate whether CFVR by TTDE can detect significant stenosis in the right coronary artery. Methods: We studied 50 patients who underwent coronary angiography. Coronary flow velocity in the posterior descending branch of the right coronary artery (PD) was measured by TTDE both at baseline and during hyperemia induced by the intravenous infusion of adenosine triphosphate. CFVR was calculated as the hyperemia/baseline (average diastolic peak velocity). Results: Adequate spectral Doppler recordings in the PD were obtained in 36 patients including 26 patients who were given an echocardiographic contrast agent to improve Doppler spectral signals. The study population was divided into 2 groups with (Group A;n = 11) and without (Group B;n = 25) significant stenosis in the right coronary artery. CFVR in Group A was significantly smaller than that in Group B (1.6±0.3versus2.5±0.4; P < 0.0001). The sensitivity of a CFVR of <2.0 for predicting the presence of significant stenosis in the right coronary artery was 91%, and the specificity was 88%. Conclusions: The measurement of CFVR in the PD by TTDE is useful for the noninvasive assessment of significant stenosis in the right coronary artery. (ECHOCARDIOGRAPHY, Volume 20, August 2003) [source]

    Estimation of Coronary Flow Velocity Reserve Using Transthoracic Doppler Echocardiography and Cold Pressor Test Might Be Useful for Detecting of Patients with Variant Angina

    ECHOCARDIOGRAPHY, Issue 4 2010
    Hui-Jeong Hwang M.D.
    Purpose: The cold pressor test (CPT) has been used to detect variant angina, but its sensitivity in predicting vasospasm is low. The aim of this study was to determine whether estimates of the coronary flow velocity reserve (CFVR) in the distal left anterior descending coronary artery (dLAD) using transthoracic echocardiography (TTE) and CPT are useful tool to predict variant angina. Methods: 65 patients (mean age = 52 ± 10 years; male:female = 41:24) who had normal coronary artery on angiography and underwent acetylcholine provocation test were enrolled and divided into the spasm group (n = 31) and the no spasm group (n = 34). During CPT, the peak (PDV) and mean diastolic flow velocity (MDV) of the dLAD were estimated using TTE with a high-frequency transducer, and electrocardiography, blood pressures, heart rate, and symptoms were monitored every 30 seconds. CPT%PDV and CPT%MDV were defined as the percentage changes in PDV and MDV during CPT, respectively. Results: CPT%PDV was 4.99 ± 23.62% in the spasm group and 52.75 ± 24.78% in the no spasm group (P < 0.001). CPT%MDV was 6.83 ± 23.81% in the spasm group and 50.22 ± 27.83% in the no spasm group (P < 0.001). CPT%PDV<31.1% had a sensitivity of 93.5% and a specificity of 82.4% in predicting variant angina (95% confidence interval [CI]: 0.939,0.979, P < 0.001). CPT%MDV<30.55% had a sensitivity of 90% and a specificity of 76.5% in predicting variant angina (95% CI: 0.884,0.950, P < 0.001). Conclusion: The measurement of changes in the coronary flow velocity of the dLAD using TTE and CPT might be useful for the estimation of endothelial dysfunction in patients with variant angina. (ECHOCARDIOGRAPHY 2010;27:435-441) [source]

    Proximal Coronary Hemodynamic Changes Evaluated by Intracardiac Echocardiography during Myocardial Ischemia and Reperfusion in a Canine Model

    ECHOCARDIOGRAPHY, Issue 3 2008
    Beibei Han M.D.
    Background: The purpose of this study was to assess whether the dynamic changes in coronary flow velocity and coronary flow velocity reserve (CFVR) by intracardiac echocardiography (ICE) within proximal coronary arteries are related to myocardial perfusion status and infarct size in a myocardial ischemia-reperfusion injury model. Methods: In 14 dogs, left anterior descending coronary artery (LAD) was ligated for 2 hours followed by 2 hours reperfusion. Coronary flow velocity was obtained by ICE within coronary arteries at baseline, and at the end of both occlusion and reperfusion period. The CFVR was calculated as the ratio of hyperemic to resting peak diastolic velocity (PDV). Myocardial perfusion was evaluated by real time myocardial contrast echocardiography (MCE). The infarct area was detected by triphenyltetrazolium chloride (TTC) staining and expressed as the percentage of the whole left ventricular (LV) area. Results: CFVR significantly decreased both in proximal LAD and left circumflex (LCx) artery at the end of occlusion, and did not recover at the end of reperfusion. However, no significant difference in flow parameters was observed between dogs with myocardial perfusion defect and those without. CFVR in LAD at the end of reperfusion did not correlate with the infarct size (r =,0.182, P = NS) either. Conclusions: Decreased CFVR detected by ICE occurs both in ischemic and in nonischemic proximal arteries during myocardial ischemia and early stage of reperfusion. This change in CFVR has poor correlation with the extent of microvascular impairment and cannot be used to predict infarct size. [source]

    Noninvasive Coronary Flow Velocity Reserve Measurement in the Posterior Descending Coronary Artery for Detecting Coronary Stenosis in the Right Coronary Artery Using Contrast-Enhanced Transthoracic Doppler Echocardiography

    ECHOCARDIOGRAPHY, Issue 3 2004
    Hiroyuki Watanabe M.D.
    Background: Coronary flow velocity reserve (CFVR) measurement by transthoracic Doppler echocardiography (TTDE) has been found to be useful for assessing left anterior descending coronary artery (LAD) stenosis. However, this method has been restricted only for the LAD. The purpose of this study was to detect severe right coronary artery (RCA) stenosis by CFVR measurement using contrast-enhanced TTDE. Methods: In 60 consecutive patients with angina pectoris (mean (SD) age: 60 (11), 18 women), coronary flow velocities in the RCA were recorded in the postero-descending coronary artery by contrast-enhanced TTDE at rest and during hyperemia induced by intravenous infusion of adenosine triphosphate (140 mcg/ml/kg). CFVR was calculated as the ratio of hyperemic to basal peak and mean diastolic flow velocity. CFVR measurements by TTDE were compared with the results of coronary angiography performed within 1 week. Results: Coronary flow velocity was successfully recorded in 49 (82%) of the 60 patients with contrast agent. CFVR (mean (SD)) was 1.4 (0.4) in patients with, and 2.6 (0.6) in patients without significant stenosis in the RCA (%diameter stenosis > 75%, P < 0.001). Using the cutoff value 2.0 for CFVR in the RCA, its sensitivity and specificity in detecting significant stenosis in the RCA were 88% and 91%, respectively. Conclusion: CFVR measurement in the postero-descending coronary artery by contrast enhanced TTDE is a new, noninvasive method to detect significant stenosis in the RCA. (ECHOCARDIOGRAPHY, Volume 21, April 2004) [source]

    Noninvasive Assessment of Significant Right Coronary Artery Stenosis Based on Coronary Flow Velocity Reserve in the Right Coronary Artery by Transthoracic Doppler Echocardiography

    ECHOCARDIOGRAPHY, Issue 6 2003
    M.D., Yoshiki Ueno
    Background: Coronary flow velocity reserve (CFVR) measured by transthoracic Doppler echocardiography (TTDE) has been reported to be useful for the noninvasive assessment of coronary stenosis in the left anterior descending artery. However, the measurement of CFVR in the right coronary artery by TTDE has not yet been validated in a clinical study. Objective: The aim of this study was to evaluate whether CFVR by TTDE can detect significant stenosis in the right coronary artery. Methods: We studied 50 patients who underwent coronary angiography. Coronary flow velocity in the posterior descending branch of the right coronary artery (PD) was measured by TTDE both at baseline and during hyperemia induced by the intravenous infusion of adenosine triphosphate. CFVR was calculated as the hyperemia/baseline (average diastolic peak velocity). Results: Adequate spectral Doppler recordings in the PD were obtained in 36 patients including 26 patients who were given an echocardiographic contrast agent to improve Doppler spectral signals. The study population was divided into 2 groups with (Group A;n = 11) and without (Group B;n = 25) significant stenosis in the right coronary artery. CFVR in Group A was significantly smaller than that in Group B (1.6±0.3versus2.5±0.4; P < 0.0001). The sensitivity of a CFVR of <2.0 for predicting the presence of significant stenosis in the right coronary artery was 91%, and the specificity was 88%. Conclusions: The measurement of CFVR in the PD by TTDE is useful for the noninvasive assessment of significant stenosis in the right coronary artery. (ECHOCARDIOGRAPHY, Volume 20, August 2003) [source]

    Effects of left ventricular unloading by Impella recover LP2.5 on coronary hemodynamics

    CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 4 2007
    Maurice Remmelink MD
    Abstract Objectives: We studied the effects of LV unloading by the Impella on coronary hemodynamics by simultaneously measuring intracoronary pressure and flow and the derived parameters fractional flow reserve (FFR), coronary flow velocity reserve (CFVR), and coronary microvascular resistance (MR). Background: Patients with compromised left ventricular (LV) function undergoing high-risk percutaneous coronary intervention (PCI) may benefit from LV unloading. Limited information is available on the effects of LV unloading on coronary hemodynamics. Methods: Eleven patients (mean LV ejection fraction of 35 ± 11%) underwent PCI during LV support by the LV unloading device (Impella Recover® LP2.5). Intracoronary measurements were performed in a nonstenotic coronary artery after the PCI, before and after adenosine-induced hyperemia at four different support levels (0,2.5 L/min). Results: Aortic and coronary pressure increased with increasing support levels, whereas FFR remained unchanged. Baseline flow velocity remained unchanged, while hyperemic flow velocity and CFVR increased significantly with increasing support levels (61 ± 24 to 72 ± 27 cm/sec, P = 0.001 and 1.88 ± 0.52 to 2.34 ± 0.63, P < 0.001 respectively). The difference between baseline MR and hyperemic MR significantly increased with increasing support levels (1.28 ± 1.32 to 1.89 ± 1.43 mm Hg cm,1 sec, P = 0.005). Conclusions: Unloading of the LV by the Impella increased aortic and intracoronary pressure, hyperemic flow velocity and CFVR, and decreased MR. The Impella-induced increase in coronary flow, probably results from both an increased perfusion pressure and a decreased LV volume-related intramyocardial resistance. © 2007 Wiley-Liss, Inc. [source]