Search

Abstract Background Coronary chronic total occlusion (CTO) is characterized by the presence of collateral blood vessels which can provide additional blood supply to CTO-artery dependent myocardium. Successful CTO recanalization is followed by significant decrease in collateral donor artery blood flow and collateral derecruitment, but data on coronary hemodynamic changes in relation to myocardial function are limited. We assessed changes in coronary flow velocity reserve (CFVR) by echocardiography in collateral donor and recanalized artery following successful opening of coronary CTO. Methods Our study enrolled 31 patients (60 ± 9 years; 22 male) with CTO and viable myocardium by SPECT scheduled for percutaneous coronary intervention (PCI). Non-invasive CFVR was measured in collateral donor artery before PCI, 24 h and 6 months post-PCI, and 24 h and 6 months in recanalized artery following successful PCI of CTO. Results Collateral donor artery showed significant increase in CFVR 24 h after CTO recanalization compared to pre-PCI values (2.30 ± 0.49 vs. 2.71 ± 0.45, p = 0.005), which remained unchanged after 6-months (2.68 ± 0.24). Baseline blood flow velocity of the collateral donor artery significantly decreased 24 h post-PCI compared to pre-PCI (0.28 ± 0.06 vs. 0.24 ± 0.04 m/s), and remained similar after 6 months, with no significant difference in maximum hyperemic blood flow velocity pre-PCI, 24 h and 6 months post-PCI. CFVR of the recanalized coronary artery 24 h post-PCI was 2.55 ± 0.35, and remained similar 6 months later (2.62 ± 0.26, p = NS). Conclusions In patients with viable myocardium, prompt and significant CFVR increase in both recanalized and collateral donor artery, was observed within 24 h after successful recanalization of CTO artery, which maintained constant during the 6 months. Trial registration ClinicalTrials.gov (Number NCT04060615 ).

Background: Coronary chronic total occlusion (CTO) is characterized by the presence of collateral blood vessels which can provide additional blood supply to CTO-artery dependent myocardium. Successful CTO recanalization is followed by significant decrease in collateral donor artery blood flow and collateral derecruitment, but data on coronary hemodynamic changes in relation to myocardial function are limited. We assessed changes in coronary flow velocity reserve (CFVR) by echocardiography in collateral donor and recanalized artery following successful opening of coronary CTO.Methods: Our study enrolled 31 patients (60 ± 9 years; 22 male) with CTO and viable myocardium by SPECT scheduled for percutaneous coronary intervention (PCI). Non-invasive CFVR was measured in collateral donor artery before PCI, 24 h and 6 months post-PCI, and 24 h and 6 months in recanalized artery following successful PCI of CTO.Results: Collateral donor artery showed significant increase in CFVR 24 h after CTO recanalization compared to pre-PCI values (2.30 ± 0.49 vs. 2.71 ± 0.45, p = 0.005), which remained unchanged after 6-months (2.68 ± 0.24). Baseline blood flow velocity of the collateral donor artery significantly decreased 24 h post-PCI compared to pre-PCI (0.28 ± 0.06 vs. 0.24 ± 0.04 m/s), and remained similar after 6 months, with no significant difference in maximum hyperemic blood flow velocity pre-PCI, 24 h and 6 months post-PCI. CFVR of the recanalized coronary artery 24 h post-PCI was 2.55 ± 0.35, and remained similar 6 months later (2.62 ± 0.26, p = NS).Conclusions: In patients with viable myocardium, prompt and significant CFVR increase in both recanalized and collateral donor artery, was observed within 24 h after successful recanalization of CTO artery, which maintained constant during the 6 months.Trial Registration: ClinicalTrials.gov (Number NCT04060615 ). [ABSTRACT FROM AUTHOR]

Background: In patients with end-stage renal disease requiring hemodialysis (HD patients), myocardial ischemia after coronary artery disease is a major cause of mortality. Coronary pathophysiology, namely myocardial microvascular dysfunction, appears to differ from patients not requiring HD (non-HD patients).Objectives: We compared functional improvement of myocardial ischemia after coronary artery bypass surgery (CABG) between HD and non-HD patients by transthoracic coronary flow velocity reserve (CFVR).Methods: We retrospectively reviewed isolated CABG patients from between 2008 and 2017. Finally, 161 patients were enrolled; each underwent pre- and postoperative CFVR assessment, and left anterior descending (LAD) artery revascularization with "in-situ" internal mammary artery (IMA). Graft patency was confirmed, and after successful CABG, postoperative CFVR improvement between the two groups was compared.Results: Preoperative CFVR value in group H was 1.81 ± 0.52, group N was 1.93 ± 0.66. There was no significant difference between the groups. IMA to LAD grafts were patent in postoperative evaluation in all patients. Postoperative CFVR in group H was 2.48 ± 0.72 and group N was 2.83 ± 0.73 (P = .042). Significant difference was observed.Conclusion: In both groups, CFVR values improved after successful CABG, but postoperative CFVR values were significant different. In younger populations CFVR values are generally higher. Our HD group was significantly younger than the non-HD group, but CFVR values were postoperatively significantly lower. CFVR values are reportedly affected by both epicardial and microcoronary circulation. In this study population, as all grafts to the LAD were patent, the lower CFVR value in the HD group was considered to have resulted in microvascular disorders. [ABSTRACT FROM AUTHOR]

: ObjectivesThe purpose of this study was to determine the feasibility of coronary flow velocity reserve (CFVR) measurement by transthoracic Doppler echocardiography (TTDE) in children with Kawasaki disease (KD).: BackgroundDoppler-derived CFVR is a reliable marker predicting the presence of myocardial ischemia.: MethodsWe studied 49 patients (median age 11 years) with KD. The CFVR was calculated as the ratio of hyperemic to basal peak (peak CFVR) and mean (mean CFVR) diastolic flow velocities in the posterior descending coronary artery (PD) and left anterior descending coronary artery (LAD). The CFVR measurements by TTDE were compared with the results of coronary angiography, thallium-201 (Tl-201) single-photon emission computed tomography (SPECT), and intracoronary Doppler study.: ResultsThe CFVR measurements by TTDE were obtained in 92 (94%) of 98 vessels of the PD and LAD in 49 study patients. Both peak and mean CFVRs for 21 stenotic vessels were significantly smaller than those for 35 normal vessels and for 20 vessels with aneurysmal lesions (p < 0.0001). Peak and mean CFVR <2.0 predicted significant coronary stenosis, as determined by coronary angiography, with sensitivities and specificities of 89% and 96% and 89% and 97%, respectively. Also, both peak and mean CFVRs were correlated with reversible perfusion defects on Tl-201 SPECT (agreement 80%; kappa 0.4). The correlation between peak and mean CFVRs determined by the TTDE and intracoronary Doppler studies in 36 vessels of 23 patients were 0.76 and 0.80, respectively.: ConclusionsThe CFVR measured by TTDE predicts the presence of significant coronary stenosis of either the right coronary artery or LAD, as well as myocardial ischemia of these territories in children with KD. [Copyright &y& Elsevier]

: ObjectivesThe present study sought to investigate the use of transthoracic Doppler harmonic echocardiography (TTDHE) to evaluate changes in coronary flow dynamics due to microvascular dysfunction.: BackgroundCoronary flow velocity reserve (CFVR) measurements by TTDHE are useful for assessing epicardial coronary artery stenoses. It remains unclear, however, if microvascular disease can be detected.: MethodsIn 54 patients with chest pain, intracoronary Doppler (ICD) and TTDHE were used to measure average peak velocity at baseline and hyperemia. Significant coronary lesions had been ruled out by both angiography and intravascular ultrasound. Comparative measurements were performed in the distal left anterior descending coronary artery after intracoronary and intravenous administration of adenosine, and CFVR was calculated. Hypertensive patients (n = 25) were studied and compared to a control group (26 normotensive individuals).: ResultsThree patients (5%) had to be excluded because of insufficient image quality or side effects. In both groups, TTDHE-derived CFVR data correlated closely with ICD measurements (group 1: y = 0.67x + 0.076, standard error of estimate [SEE] = 0.25, r = 0.87, p < 0.001; group 2: y = 0.64x + 1.11, SEE = 0.26, r = 0.87, p < 0.001). CFVR was lower in hypertensives than in normotensive controls (2.44 ± 0.49 vs. 3.33 ± 0.40, p < 0.001, cut point = 2.84).: ConclusionsThe newly described echocardiographic method is suitable for assessing microvascular dysfunction noninvasively and corresponds well to invasive measurements. [Copyright &y& Elsevier]

: ObjectivesWe assessed the feasibility and reproducibility of the instantaneous diastolic coronary flow velocity-pressure gradient relation to characterize different degrees of coronary stenoses.: BackgroundAssessment of the hemodynamic significance of coronary stenoses can be difficult. Using sensor-tipped guidewires, various physiologic indexes can be determined in the catheterization laboratory. Each of the current methods, however, has limitations.: MethodsAfter positioning a Doppler flow wire and a pressure wire distal of a coronary stenosis, the flow velocity signals and the proximal and distal pressure were sampled simultaneously, at baseline and after intracoronary administration of adenosine. The instantaneous diastolic flow velocity and pressure gradient of single cardiac cycles at baseline, at maximal and intermediate hyperemia were plotted. Data were fitted with a regression line using the equation: ΔP= 0 +kv+Sv2. Measurements were performed in 11 normal coronary arteries, 20 intermediate stenoses and in 7 severe stenoses before and after percutaneous transluminal coronary angioplasty plus stenting.: ResultsWe found significant differences between normal coronary arteries, intermediate and severe stenoses. Percutaneous transluminal coronary angioplasty nearly normalized the highly abnormal flow-pressure gradient relation in the severe stenoses. A high degree of reproducibility was observed. In 3% of the measurements, analysis was not possible due to the occurrence of pressure drift or bad flow velocity signals.: ConclusionsIt is feasible to assess the diastolic flow velocity-pressure gradient relation over a wide range of stenoses. It characterizes the hemodynamics of epicardial coronary stenoses and allows discrimination between normal coronary arteries, intermediate and severe stenoses. [Copyright &y& Elsevier]

: ObjectivesThis study aimed to investigate the roles of intracoronary derived coronary flow velocity reserve (CFVR) and myocardial perfusion scintigraphy (single photon emission computed tomography, or SPECT) for management of an intermediate lesion in patients with multivessel coronary artery disease.: BackgroundEvaluation of the functional significance of intermediate coronary narrowings (40% to 70% diameter stenosis) is important for clinical decision making and risk stratification.: MethodsIn a prospective, multicenter study, SPECT was performed in 191 patients with stable angina and multivessel disease and scheduled for angioplasty (percutaneous transluminal coronary angioplasty, or PTCA) of a severe coronary narrowing. Coronary flow velocity reserve was determined selectively distal to an intermediate lesion in another artery using a Doppler guidewire. Percutaneous transluminal coronary angioplasty of the intermediate lesion was deferred when SPECT was negative or CFVR ≥2.0. Patients were followed for one year to document major cardiac events (death, infarction, revascularization), related to the intermediate lesion.: ResultsReversible perfusion defects were documented in the area of the intermediate lesion in 30 (16%) patients; CFVR was positive in 46 (24%) patients. Percutaneous transluminal coronary angioplasty of the intermediate lesion was deferred in 182 patients. During follow-up, 19 events occurred (3 myocardial infarctions, 16 revascularizations). Coronary flow velocity reserve was a more accurate predictor of cardiac events than was SPECT; relative risk: CFVR 3.9 (1.7 to 9.1), p < 0.05; SPECT 0.5 (0.1 to 3.2), p = NS. Multivariate analysis revealed CFVR as the only significant predictor for cardiac events.: ConclusionsDeferral of PTCA of intermediate lesions in multivessel disease is safe when CFVR ≥2.0 (event rate 6%). This selective evaluation of coronary lesion severity during cardiac catheterization allows a more accurate risk stratification than does SPECT, which is important for clinical decision making in this patient cohort. [Copyright &y& Elsevier]

Background: The aim of this study was to test whether acceleration time of systolic coronary flow velocity could contribute to the diagnosis of coronary stenosis in patients with microvascular dysfunction, on the basis of the hypothesis that systolic coronary flow is less influenced by microvascular function because of compressed myocardium., Methods: Coronary flow velocity was assessed in the left anterior descending coronary artery during hyperemia with intravenous adenosine by echocardiography in 502 patients who were scheduled for coronary angiography because of coronary artery disease and significant valvular disease. Coronary flow velocity reserve (CFVR) and the percentage acceleration time (%AT), as the percentage of the time from the beginning to the peak of systolic coronary flow over systolic time during hyperemia, were calculated. The diagnostic ability of CFVR and %AT for angiographic coronary artery stenosis was then analyzed. As invasive substudies, fractional flow reserve and %AT by a dual-sensor (pressure and Doppler velocity) guidewire were measured simultaneously with %AT on transthoracic echocardiography (n = 14)., Results: Patients with coronary stenosis had significantly lower CFVR (1.7 ± 0.4) and greater %AT (65 ± 9%) compared with those without stenosis (2.6 ± 0.6 and 50 ± 13%, respectively). Percentage acceleration time by Doppler echocardiography was in good agreement with %AT (r = 0.98) and fractional flow reserve (r = 0.74) invasively measured by dual-sensor guidewire. Cutoff values of CFVR and %AT were determined as 2.0 and 60% in receiver operating characteristic curve analysis. The sensitivity, specificity, and accuracy of CFVR to detect coronary stenosis were 71.1%, 77.3%, and 75.4%, while those of %AT were 83.4%, 71.8%, and 75.4%, respectively. In addition, %AT provided high accuracy to detect coronary stenosis, especially in patients with previous myocardial infarctions, valvular disease, and left ventricular hypertrophy (81.1%, 84.1%, and 73.4%, respectively)., Conclusions: The %AT of systolic coronary flow velocity is a promising marker to diagnose coronary stenosis in patients with microvascular dysfunction., (Copyright © 2014 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.)