Coronary Artery Flow Velocity Research Articles

Predictors of diastolic deceleration time of coronary flow velocity of infarct related and reference coronary artery assessed by transthoracic Doppler echocardiography in the chronic phase of successfully reperfused anterior myocardial infarction: relation to infarct size.

High-frequency transthoracic Doppler echocardiography (TDE) enables the assessment of flow velocity and velocity pattern in different coronary arteries, including the assessment of diastolic deceleration time (DDT) of coronary flow velocity. Short DDT of infarct related artery (IRA) (<600 msec) in the acute phase of anterior myocardial infarction (MI) is the predictor of adverse left ventricular (LV) remodeling and prognosis. The significance of DDT of coronary flow velocity assessment in the chronic phase of anterior MI is not well established. Our study aimed to establish the predictors of DDT of the coronary flow velocity of infarct related (left anterior descendent-DDT of LAD) and reference coronary artery, evaluated by TDE, and to assess their relation to infarct size in the chronic phase of successfully reperfused first anterior MI. Our study included 40 consecutive patients (34 men, mean age 52 ± 12 years) one month after the first anterior STEMI and single vessel disease successfully treated with primary PCI. All patients underwent SPECT MPI for the assessment of LV volumes, ejection fraction, and percentage of the myocardium with fixed perfusion abnormalities and echocardiographic examination including the evaluation of DDT of IRA and reference coronary artery TDE. DDT of LAD correlated significantly to the WMSI (r = -0.467, p = 0.002), LV end-systolic volume (r = -0.412, p = 0.008), LV ejection fraction (r = 0.427, p = 0.006), while the strongest correlation was observed between DDT of LAD and the extent of fixed perfusion abnormality (r = -0.627, p < 0.0001), Multivariate analysis revealed percentage of fixed perfusion abnormalities along with DDT of reference coronary artery as the independent predictors of DDT of IRA. DDT of IRA shorter than 886 msec predicts large fixed perfusion abnormalities (>20%) with a sensitivity of 89% and specificity of 62% (AUC 0.842). DDT of LAD assessed by TDE in the chronic phase of successfully reperfused first anterior MI is a usefull variable for the assessment of microcirculatory function that exclusively reflects the extent of microvascular damage and relates to infarct size.

Temporal changes in coronary artery function and flow velocity reserve in mice exposed to chronic intermittent hypoxia.

Obstructive sleep apnea (OSA) is a chronic condition characterized by intermittent hypoxia (IH) that is implicated in an increased risk of cardiovascular disease (i.e., coronary heart disease, CHD) and associated with increased overall and cardiac-specific mortality. Accordingly, we tested the hypothesis that experimental IH progressively impairs coronary vascular function and in vivo coronary flow reserve. Male C57BL/6J mice (8-week-old) were exposed to IH (FiO2 21% 90 s-6% 90 s) or room air (RA; 21%) 12 h/day during the light cycle for 2, 6, 16, and 28 weeks. Coronary artery flow velocity reserve (CFVR) was measured at each time point using a Doppler system. After euthanasia, coronary arteries were micro-dissected and mounted on wire myograph to assess reactivity to acetylcholine (ACh) and sodium nitroprusside (SNP). Endothelium-dependent coronary relaxation to ACh was preserved after 2 weeks of IH (80.6 ± 7.8%) compared to RA (87.8 ± 7.8%, p = 0.23), but was significantly impaired after 6 weeks of IH (58.7 ± 16.2%, p = 0.02). Compared to ACh responses at 6 weeks, endothelial dysfunction was more pronounced in mice exposed to 16 weeks (48.2 ± 5.3%) but did not worsen following 28 weeks of IH (44.8 ± 11.6%). A 2-week normoxic recovery after a 6-week IH exposure reversed the ACh abnormalities. CFVR was significantly reduced after 6 (p = 0.0006) and 28 weeks (p < 0.0001) of IH when compared to controls. Chronic IH emulating the hypoxia-re-oxygenation cycles of moderate-to-severe OSA promotes coronary artery endothelial dysfunction and CFVR reductions in mice, which progressively worsen until reaching asymptote between 16 and 28 weeks. Normoxic recovery after 6 weeks exposure reverses the vascular abnormalities.

New Porcine Model of Arteriovenous Fistula Documents Increased Coronary Blood Flow at the Cost of Brain Perfusion.

Background: Arteriovenous fistulas (AVF) represent a low resistant circuit. It is known that their opening leads to decreased systemic vascular resistance, increased cardiac output and other hemodynamic changes. Possible competition of AVF and perfusion of other organs has been observed before, however the specific impact of AVF has not been elucidated yet. Previous animal models studied long-term changes associated with a surgically created high flow AVF. The aim of this study was to create a simple AVF model for the analysis of acute hemodynamic changes. Methods: Domestic female pigs weighing 62.6 ± 5.2 kg were used. All the experiments were held under general anesthesia. The AVF was created using high-diameter ECMO cannulas inserted into femoral artery and vein. Continuous hemodynamic monitoring was performed throughout the protocol. Near-infrared spectroscopy sensors, flow probes and flow wires were inserted to study brain and heart perfusion. Results: AVF blood flow was 2.1 ± 0.5 L/min, which represented around 23% of cardiac output. We observed increase in cardiac output (from 7.02 ± 2.35 L/min to 9.19 ± 2.99 L/min, p = 0.0001) driven dominantly by increased heart rate, increased pulmonary artery pressure, and associated right ventricular work. Coronary artery flow velocity rose. On the contrary, carotid artery flow and brain and muscle tissue oxygenation measured by NIRS decreased significantly. Conclusions: Our new non-surgical AVF model is reproducible and demonstrated an acute decrease of brain and muscle perfusion.

Dynamics of coronary artery velocity flow during exercise echocardiography

Purpose The aim of our study was to acquire non-invasive data from coronary flow velocity profiles during exercise in groups of healthy subjects and of patients with arterial hypertension. Material and Methods We enrolled 83 patients into two groups: (1) 35 non-selected consecutive healthy subjects; (2) 25 consecutive patients with arterial hypertension. All the patients performed supine bicycle symptoms-limited tests. Throughout exercise the diastolic peaks of coronary flow velocity in LAD were recorded. Coronary flow velocity reserve (CFVR) was calculated off-line. Profiles of coronary artery velocity were acquired for all groups. The coronary artery flow parameters investigated were comparable in healthy and hypertensive patients at every stage. Results The average diastolic velocities were 54.8 ± 12.9 vs. 51.8 ± 12.2 cm/s, at 50 W; 69.2 ± 17.1 vs 64.4 ± 19.1 cm/s at 75 W; 70.7 ± 16.4 vs. 76.1 ± 19.0 cm/s at 100 W; 80.0 ± 16.0 vs. 72.9 ± 16.1 cm/s at 125 W; 83.7 ± 12.2 vs. 81.4 ± 17.0 at 150 W, p- non-significant, respectively. On average, the healthy group reached CFVR > 2.0 at a heart rate of 110–120 beats/min at 75 W. During supine bicycle exercise, healthy subjects and patients with arterial hypertension have a similar coronary artery flow velocity profile. Conclusion The routine exercise echocardiography test can feasibly be supplemented with the additional measurement of coronary flow velocity during routine supine exercise stress tests, as the normal range of CFVR is reached before submaximal heart rate.

Prognostic value of non-invasive coronary artery flow velocity assessment in elderly patients

Abstract Funding Acknowledgements Type of funding sources: None. Background There is a high prevalence of coronary artery disease (CAD) in the elderly population. However, symptoms of CAD are often non-specific. Dyspnoe, non-anginal pains are among the main symptoms in older patients. Exercise tests are of limited feasibility in these patients, due to neuro-muscular weakness, physical deconditioning, and orthopaedic limitations. Pharmacological tests often are contraindicated in a substantial percentage of elderly patients. Some recent studies indicate using local flow acceleration during routine echocardiography has prognostic potential for coronary artery assessments without stress testing. The aim of the study was to define the prognostic value of coronary artery ultrasound assessment in patients ≥75 years old. Methods This is a prospective cohort study. Patients ≥ 75 years old who underwent routine echocardiography with additional scans for coronary arteries over a period of 24 months were included in the study. The study group consisted of 80 patients aged 75-90 years (56 women; mean age 79 ± 4). Initial exams were performed for other reasons, primarily for arterial hypertension. Fifteen patients had known CAD. Death, non-fatal myocardial infarction (MI), and revascularization were defined as major adverse cardiac events (MACE). All patients were followed up with at a median of 32 months. Results There were 34 patients with high local velocities in the left coronary artery. Eight deaths, two non-fatal myocardial infarctions occurred, and 13 revascularizations were performed. With a ROC analysis, a coronary flow velocity &amp;gt;110 cm/s was the best predictor for risk of death (area under curve 0.84 [95% CI 0.74–0.92]; sensitivity 75%; specificity 88%). Only the maximal velocity in proximal left-sided coronary arteries was independently associated with death (HR 1.03, 95% CI 1.01; 1.05; p &amp;lt; 0.002), or death/MI (HR 1.03, 95% CI 1.01; 1.04; p &amp;lt; 0.0001). The cut-off value of 66 cm/s was a predictor of all MACE (area under curve 0.87 [95% CI 0.77–0.94]; sensitivity 80%; specificity 86%). Any causes of death or MI occurred more frequently in patients with velocities of &amp;gt;66 cm/s (27% vs. 2%; p &amp;lt; 0.002). The rates of MACE were 58.0% vs. 2%; p &amp;lt; 0.0000001, respectively. Conclusion The analysis of coronary flow in the left coronary artery during echocardiography can be used as a predictor of outcomes in elderly patients. Maximal velocities in proximal left-sided coronary arteries is independently associated with further death or myocardial infarction.

P1293 Coronary artery flow velocity alteration by transthoracic echo in a group of young adult males

Abstract Funding Acknowledgements university Grand Background Atherosclerosis is a chronic and progressive disease that causes high mortality primarily in persons over the age of forty. However, a lot of atherosclerosis cases are only discovered after a fatal cardiovascular event. Several techniques can be used to identify atherosclerosis when it is still in its subclinical stages and at ages before the symptoms of atherosclerosis became marked. The SCORE chart and other scores were developed for this purpose. However, the SCORE chart doesn’t cover the people under 40 years old. A significant portion of patients with a high risk of cardiovascular disease have major cardiac events before reaching 40 years of age. The aim of the study was to define subclinical coronary flow alteration in apparently healthy men between the ages of 30-39. Methods This is part of a study intended to facilitate risk estimation in apparently healthy persons between 30 and 39 years old with no documented cardiovascular disease. Seventy-two consecutive men (34 ± 3 years old) who were assumed healthy, were recruited into the study. A standard cardiology exam; analysis of blood lipids; basic transthoracic echocardiography examination with additional scans of the left main, left anterior descending, and circumflex arteries; and carotid ultrasound were performed. Results Among the study population there were eight obese patients (12.5%), twenty-two (22%) smokers, forty-eight (66%) had dyslipidaemias, and six (8%) had a first-degree relative with known premature coronary or vascular events. All of them had a normal ejection fraction (65 ± 4%) and heart chamber sizes. The mean global longitudinal strain (GLS) was -19.3 ± 2%, myocardial mass index was 77 ± 12 g/m2, and intima-media thickness (IMT) was 0.74 ± 0.19 mm. Intima-media thickening at standard site was found in twelve patients (17%, 95% CI 9-26%), atherosclerosis with pronounced plaques in carotid arteries was diagnosed in twenty-one man (29%, 95% CI 19-40%). The group with atherosclerotic plaques had a higher maximal velocity in coronary arteries (44 ± 16 vs. 33 ± 11 cm/s, p &amp;lt; 0.002) compared to other patients. Ejection fraction (65 ± 5 vs. 65 ± 4 %, p = 0.93), myocardial mass index (81 ± 13 vs. 75 ± 12, g/m2 p = 0.053), and GLS (-19 ± 3 vs. -19 ± 2 %, p = 0.55) were similar. There was a significant correlation between IMT and maximal velocity in coronary arteries (r=-0.44, p &amp;lt; 0.0005). Three patients of atherosclerotic group (14%, 95% CI 3-32%) had coronary flow velocity more than 68 cm/s corresponding significant coronary artery lesions. Conclusion There is a high prevalence of subclinical atherosclerosis among men between the ages of 30 and 39 in a population with a high risk of cardiovascular disease by SCORE chart. Coronary flow velocity assessment could be helpful for detection of coronary lesions in young adult patients with carotid plaques.

Estimation of Blood Flow Velocity in Coronary Arteries Based on the Movement of Radiopaque Agent

Estimation of Blood Flow Velocity in Coronary Arteries Based on the Movement of Radiopaque Agent

THE ROLE OF MYOCARDIAL REVASCULARIZATION IN THE SURVIVAL OF PATIENTS WITH ALTERED CORONARY BLOOD FLOW DETECTED BY TRANSTHORACIC ULTRASOUND

Aim of the study was to identify the effects of myocardial revascularization on the prognosis in patients with altered coronary blood flow detected by transthoracic ultrasound.Material and Methods. Four hundred and twelve (412) patients were included in the study. The inclusion criterion was coronary velocity more than 70 cm/s during echocardiography. The study population was divided into three groups: Group 1 comprised patients with high velocities in the coronary arteries detected by ultrasound, in whom myocardial revascularization was performed; Group 2 comprised patients with high velocities in the coronary arteries, in whom myocardial revascularization was not performed and; the Control Group comprised patients with normal coronary blood flow according to ultrasound. The follow-up period was 10–11 months.Results. Seventeen (17) deaths (4.7%) occurred during follow-up. Death rates were 1.6 vs. 8.1 vs. 0% in Group 1, Group 2 and the Control Group, respectively, with a p-value for the difference between Group 1 and Group 2 (p1) of &lt;0.009; and a p-value for the differences compared with the Control group (р2) of &lt;0.03. Death, myocardial infarction, pulmonary edema, and acute coronary syndrome were observed in 27 patients (7.7% of the study group with accelerated blood flow). The rates of these outcomes were 4.9 vs. 11.0 vs. 0% in Group 1, Group 2, and the Control Group, respectively (p1&lt;0.05; p2&lt;0.006). Discussion. The study showed high rates of mortality or acute coronary events in the group of patients with pathologically high coronary flow velocities. The positive effects of revascularization on survival in this group were verified.Conclusions: 1. Left artery coronary flow velocities over 70 cm/s indicate a high probability of death or acute coronary events within 10.5 months.2. Myocardial revascularization has a significant positive effect on the survival rate and incidence of acute coronary events in patients with coronary artery flow velocities greater than 70 cm/s.3. Patients with high coronary blood flow velocities should be referred to coronary angiography or other diagnostic tests without waiting for clinical manifestations and specific symptoms for coronary artery disease.

THE ROLE OF MYOCARDIAL REVASCULARIZATION IN THE SURVIVAL OF PATIENTS WITH ALTERED CORONARY BLOOD FLOW DETECTED BY TRANSTHORACIC ULTRASOUND

Aim of the study was to identify the effects of myocardial revascularization on the prognosis in patients with altered coronary blood flow detected by transthoracic ultrasound.Material and Methods. Four hundred and twelve (412) patients were included in the study. The inclusion criterion was coronary velocity more than 70 cm/s during echocardiography. The study population was divided into three groups: Group 1 comprised patients with high velocities in the coronary arteries detected by ultrasound, in whom myocardial revascularization was performed; Group 2 comprised patients with high velocities in the coronary arteries, in whom myocardial revascularization was not performed and; the Control Group comprised patients with normal coronary blood flow according to ultrasound. The follow-up period was 10–11 months.Results. Seventeen (17) deaths (4.7%) occurred during follow-up. Death rates were 1.6 vs. 8.1 vs. 0% in Group 1, Group 2 and the Control Group, respectively, with a p-value for the difference between Group 1 and Group 2 (p1) of &lt;0.009; and a p-value for the differences compared with the Control group (р2) of &lt;0.03. Death, myocardial infarction, pulmonary edema, and acute coronary syndrome were observed in 27 patients (7.7% of the study group with accelerated blood flow). The rates of these outcomes were 4.9 vs. 11.0 vs. 0% in Group 1, Group 2, and the Control Group, respectively (p1&lt;0.05; p2&lt;0.006). Discussion. The study showed high rates of mortality or acute coronary events in the group of patients with pathologically high coronary flow velocities. The positive effects of revascularization on survival in this group were verified.Conclusions: 1. Left artery coronary flow velocities over 70 cm/s indicate a high probability of death or acute coronary events within 10.5 months.2. Myocardial revascularization has a significant positive effect on the survival rate and incidence of acute coronary events in patients with coronary artery flow velocities greater than 70 cm/s.3. Patients with high coronary blood flow velocities should be referred to coronary angiography or other diagnostic tests without waiting for clinical manifestations and specific symptoms for coronary artery disease.

Resting Coronary Blood Flow Velocity by Transthoracic Coronary Echocardiography is Higher in Patients with Cardiovascular Diseases Compared with the Healthy Adults

Transthoracic Coronary Echocardiography (TCE), defined as blood velocity detection mainly in the left anterior descending artery (LAD) by noninvasive Doppler echocardiography, has been employed to measure coronary blood flow velocity and coronary flow reserve in research labs and in clinical settings. Most prior studies focused on the coronary flow reserve data, and normal values for resting coronary artery flow velocity have rarely been reported. The purpose of this study was to examine resting coronary blood flow velocity in healthy subjects and patients with cardiovascular disease. We retrospectively collected resting coronary blood flow velocity data by TCE from 69 healthy subjects (42 M, 27 F, 60 ± 8 yrs) and 37 patients (27 M, 10 F, 63 ± 10 yrs) with various cardiovascular diseases (14 peripheral arterial disease, 5 Pre‐TAVR, 8 hypertrophy cardiomyopathy, 10 CABG). The patient group had higher systolic blood pressure (135 ± 18 vs. 120±14 mmHg, P value &lt;0.001), mean blood pressure (94 ± 11 vs. 89 ±10 mmHg, P value &lt;0.05), and Rate‐Pressure Product (RPP, an index of myocardial oxygen demand) (8617 ± 1702 vs. 7249 ± 1453. P value &lt; 0.001). Resting coronary blood flow velocities early (CBV1) and late (CBV2) in diastole were significantly higher in the patient group (CBV1: 27.6±8.6 vs. 19.0 ± 4.9 cm/s, P value &lt; 0.001; CBV2: 17.6 ± 5.5 vs. 13.4 ± 3.2 cm/s, P value &lt;0.001). After controlling for oxygen consumption (CBV/RPP), resting coronary blood flow velocity during the early diastolic period was still significantly higher in patients than in the healthy group (Adjusted CBV1: 3.3 ± 1.4 vs. 2.7 ± 0.8 au, P value &lt; 0.001). There was no significant difference in adjusted coronary blood flow velocity during the late diastolic period (Patient group vs. healthy group, 2.1 ± 0.8 vs.1.9 ± 0.5 au, P value = 0.105). Further studies are needed to explore the clinical implication and importance of higher resting coronary blood flow velocity data by TCE in patients.Support or Funding InformationSupported by National Institutes of Health Grants P01 HL134609 (Sinoway), and UL1 TR002014 (Sinoway).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Prognostic value of proximal left coronary artery flow velocity detected by transthoracic Doppler echocardiography

BackgroundLesions in the proximal left coronary artery (LCA) are associated with a poor prognosis compared with other lesional sites. Transthoracic Doppler echocardiography (TTDE) can help to detect proximal LCA flow, and an accelerated coronary flow velocity (CFV) indicates the presence of proximal LCA lesions. This study aimed to investigate the prognostic value of CFV in the proximal LCA measured by TTDE. MethodsWe enrolled 1472 consecutive hemodynamically stable patients with known or suspected heart disease whose CFV was successfully detected using TTDE accompanied by routine echocardiography between 2008 and 2011. The primary outcome was cardiac death (acute myocardial infarction, heart failure, or sudden cardiac death) and patients were followed up over a median of 6.3 years. ResultsOverall, 42 cardiac deaths (3%) were observed. An increased CFV was significantly associated with the outcome in several models based on potential confounders (age, rate pressure product, Framingham Risk Score, diabetes, coronary artery disease, hemoglobin, brain natriuretic peptide, estimated glomerular filtration rate, left ventricular mass, left ventricular ejection fraction, and E/e′). Using a receiver operating characteristic curve analysis, the optimal cut-off value for the CFV to the association of the outcome was 37 cm/s (area under the curve, 0.70; sensitivity, 82%; specificity, 62%). In sequential Cox proportional hazards models, the CFV added incremental prognostic information to the clinical and basic echocardiographic parameters (chi-squared: 110.7 to 146.6, P < 0.01). ConclusionsAn increased CFV in the proximal LCA was associated with cardiac death, incremental to the clinical and basic echocardiographic parameters.

Transthoracic Coronary Flow Data at Rest Predict High-Risk Stress Tests.

Background Several recent studies have reported the opportunity to diagnose significant narrowing of the coronary arteries without stress testing using local flow acceleration. Purpose To define how often patients with increased coronary flow velocities at rest (≥ 0.70 m/s) have a positive exercise echocardiography test. Material and Methods A total of 150 patients scheduled for exercise echocardiography were studied using transthoracic Doppler echocardiography in order to assess coronary artery flow velocity before exercise. Pulsed wave Doppler registered blood flow velocity placed on the color signal. The maximal diastolic velocity of coronary flow was measured. Results Of participants, 16% had a velocity of more than 0.70 m/s in the left main/proximal left anterior/proximal left circumflex arteries (LM/pLAD). A significant correlation was observed between the value of the maximal velocity in LM/pLAD and the ejection fraction at the peak of exercise ( r ≈ -0.39, P < 0.0001); between the value of the maximal velocity in LM/pLAD and index of wall motion abnormalities (IWMA) at the peak of exercise ( r ≈ 0.44, P < 0.0001); and between the value of the maximal velocity in LM/pLAD and dIWMA ( r ≈ 0.41, P < 0.0001). Afterwards, severe ischemia in stress echocardiography tests was observed in this group. The average IWMA of these tests was found to be 2.3. Sixty-two angiograms were available for comparison with Doppler data. Conclusion There is a significant correlation between the value of the maximal velocity in LM/pLAD/pLCx at rest and the severity of wall motion abnormalities during exercise tests.

P4340Evaluation of the prognostic value of proximal left coronary artery flow velocity detected by transthoracic Doppler echocardiography

P4340Evaluation of the prognostic value of proximal left coronary artery flow velocity detected by transthoracic Doppler echocardiography

Noninvasive Coronary Flow Reserve Predicts Response to Exercise in Asymptomatic Severe Aortic Stenosis

In patients with asymptomatic aortic stenosis (AS), exercise stress echocardiography (ESE) provides additional prognostic information beyond baseline. The coronary flow velocity reserve (CFVR) is impaired in AS, but its link with exertion is unknown in this setting. The aim of this study was to test the hypothesis that CFVR could predict exercise capacity and abnormal exercise test results in AS. Noninvasive CFVR and symptom-limited semisupine ESE were prospectively performed the same day in 43 patients with asymptomatic isolated severe AS (mean age, 68.5±11years; 26% women; mean aortic valve area, 0.8±0.16cm2; mean left ventricular ejection fraction, 70±7%). CFVR was performed in the distal part of the left anterior descending coronary artery using intravenous adenosine infusion (140μg/kg/min over 2min), and ESE was performed at an initial workload of 25W with a 20- to 25-W increase at 2-min intervals. An abnormal result on ESE was defined as onset of symptoms at <75% of maximum predicted workload, electrocardiographic ST-segment depression ≥2mm during exercise, increase of systolic blood pressure<20mmHg or decrease in blood pressure, and complex ventricular arrhythmia. Seventeen patients with isolated severe asymptomatic AS, unable to exercise because of extracardiac conditions, served as a comparative group. Resting, hyperemic left anterior descending coronary artery flow velocity and CFVR (2.45±0.8 vs 2.4±0.8) were similar between the group unable to perform ESE and the ESE group (P=NS for all). Compared with patients with normal results on ESE, those with abnormal results on ESE (n=22) were older, had higher E/e' ratios, had higher resting left anterior descending coronary artery flow velocities (39±12 vs 31±8cm/sec), and had lower CFVR (2.01±0.3 vs 2.85±0.7; P<.01 for all). Furthermore, CFVR was significantly correlated with age, changes in transvalvular pressure gradient and left ventricular ejection fraction with exercise, workload (in watts), and exercise duration (P<.05 for all). After adjusting for other variables, CFVR remained independently correlated with exercise duration, workload, and abnormal results on ESE (P<.01 for all). On receiver operating characteristic curve analysis, CFVR<2.3 was the best cutoff to predict abnormal results on ESE (area under the curve=0.88±0.06, P<.01). In patients with asymptomatic severe AS, noninvasive CFVR is correlated with exercise duration and workload, and low CFVR predicts abnormal results on ESE with good accuracy.

A novel method for left anterior coronary artery flow velocity assessment by transthoracic echocardiography at the peak of a supine bicycle test.

Assessment of coronary flow is only performed during pharmacological tests. Supine bicycle tests permit the visualization of coronary flow assessments during exercise. To assess the parameters of coronary flow in the left anterior descending artery (LAD) during exercise, which could be a sign of significant LAD narrowing. A total of 253 patients were enrolled: Group 1, 186 non-selective participants before undergoing a coronary angiography; and Group 2, 67 controls without coronary artery disease (CAD). All the patients performed a supine bicycle echocardiography test. Coronary flow velocities and coronary flow velocity reserve (CFVR) were measured at the mid-segment of the LAD during exercise. Patients in Group 1 underwent a coronary angiography. In comparison with participants without significant LAD stenosis, patients with LAD lesions had a lower ΔV (16 ± 21 vs. 27 ± 20 cm/s, P < 0.04) and a lower CFVR (1.5 ± 0.8 vs. 2.0 ± 0.6, P < 0.004). In comparison with patients without significant proximal LAD stenosis, the patients with proximal LAD lesions had a lower flow velocity at the peak of exercise (49 ± 32 vs. 61 ± 19 cm/s, P < 0.02), a lower ΔV (13 ± 19 vs. 26 ± 22 cm/s, P < 0.004), and a lower CFVR (1.4 ± 0.6 vs. 1.9 ± 0.7, P < 0.0001). In comparison with the control group, the patients with LAD stenosis had a lower flow velocity at the peak of exercise, a lower ΔV, and a lower CFVR. Non-invasive CFVR measurement in the LAD could provide valuable additional information to a conventional echocardiography exercise test. In routine clinical practice, CFVR is sufficient for a diagnosis of severe stenosis.

Noninvasive assessment of coronary blood flow parameters during an exercise test in patients with arterial hypertension

Purpose. The aim of our study was to non-invasively investigate the parameters of coronary blood flow during exercise in patients with arterial hypertension. Materials and Methods. We enrolled 144 patients with arterial hypertension. All patients performed supine bicycle symptoms-limited tests. Throughout the exercise, the diastolic peaks of coronary flow velocity in left anterior descending artery (LAD) were measured. The values of diastolic velocity before and at maximal exercise, coronary flow velocity reserve (CFVR) and difference between peak and rest velocities were calculated offline. The control group consisted of 145 healthy persons. Results. The rest blood flow velocity in LAD was 33.0±8.4 cm/s, the peak velocity in LAD was 80.3±16.5 cm/s, difference of velocities was 48.2±13.9 cm/s, CFVR was 2.55±0.56. Women and men were comparable in velocity parameters during exercise test. There was no significant correlation between mass/index of left ventricle mass and velocity data in LAD. Hypertensive patients were comparable in investigated coronary artery flow parameters with healthy group. Conclusions. During supine bicycle tests, the patients with arterial hypertension have a similar coronary artery flow velocity profile with healthy persons.

Cardioplegia Dose Effect on Immediate Postoperative Alterations in Coronary Artery Flow Velocities After Congenital Cardiac Surgery

Abnormalities in coronary artery (CA) flow detected by echocardiography are increasingly used to guide clinical decisions in patient management. Increased CA flow has been seen postoperatively in congenital cardiac surgery. This study sought to determine immediate postoperative changes in left anterior descending (LAD) CA flow velocities, and to investigate possible factors associated with these changes. CA flow in the proximal LAD was sampled with pulsed-wave Doppler during trans-esophageal echocardiography imaging in the immediate preoperative and postoperative studies in 46 subjects. The peak velocity, velocity time integral (VTI), VTI corrected for heart rate (VTIc), and VTI rate pressure product (VTIrpp) were determined. The percent change in each measure between the preoperative and postoperative study was calculated and compared to age, body surface area (BSA), cardiopulmonary bypass time, cross-clamp time, and number of cardioplegia (CP) doses. The pH, oxygen saturation, temperature, and hemoglobin concentration (Hb) were compared for those with and without increased flow characteristics. There was an overall increase in LAD flow parameters in subjects who underwent congenital cardiac surgery. There was a significant and positive correlation of percent change in VTI, VTIc, and VTIrrp with number of CP doses and lower Hb. We propose that this phenomenon is likely of multifactorial origin, involving autoregulatory mechanism disturbance. The imaging and measurement of LAD flow velocities are feasible, reliable, and is positively correlated with number of CP doses. Interpretation of postoperative LAD flow velocities should be made in the context of intraoperative events since heart rate, blood pressure, and Hb concentration also influence CA flow parameters.

Ultrasound based assessment of coronary artery flow and coronary flow reserve using the pressure overload model in mice.

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow reserve (CFR) in humans. Reduced CFR is accompanied by marked intramyocardial and pericoronary fibrosis and is used as an indication of the severity of dysfunction. This study explores, step-by-step, the real-time changes measured in the coronary flow velocity, CFR and systolic to diastolic peak velocity (S/D) ratio in the setting of an aortic banding model in mice. By using a Doppler transthoracic imaging technique that yields reproducible and reliable data, the method assesses changes in flow in the septal coronary artery (SCA), for a period of over two weeks in mice, that previously either underwent aortic banding or thoracotomy. During imaging, hyperemia in all mice was induced by isoflurane, an anesthetic that increased coronary flow velocity when compared with resting flow. All images were acquired by a single imager. Two ratios, (1) CFR, the ratio between hyperemic and baseline flow velocities, and (2) systolic (S) to diastolic (D) flow were determined, using a proprietary software and by two independent observers. Importantly, the observed changes in coronary flow preceded LV dysfunction as evidenced by normal LV mass and fractional shortening (FS). The method was benchmarked against the current gold standard of coronary assessment, histopathology. The latter technique showed clear pathologic changes in the coronary artery in the form of peri-coronary fibrosis that correlated to the flow changes as assessed by echocardiography. The study underscores the value of using a non-invasive technique to monitor coronary circulation in mouse hearts. The method minimizes redundant use of research animals and demonstrates that advanced ultrasound-based indices, such as CFR and S/D ratios, can serve as viable diagnostic tools in a variety of investigational protocols including drug studies and the study of genetically modified strains.

Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow reserve (CFR) in humans. Reduced CFR is accompanied by marked intramyocardial and pericoronary fibrosis and is used as an indication of the severity of dysfunction. This study explores, step-by-step, the real-time changes measured in the coronary flow velocity, CFR and systolic to diastolic peak velocity (S/D) ratio in the setting of an aortic banding model in mice. By using a Doppler transthoracic imaging technique that yields reproducible and reliable data, the method assesses changes in flow in the septal coronary artery (SCA), for a period of over two weeks in mice, that previously either underwent aortic banding or thoracotomy. During imaging, hyperemia in all mice was induced by isoflurane, an anesthetic that increased coronary flow velocity when compared with resting flow. All images were acquired by a single imager. Two ratios, (1) CFR, the ratio between hyperemic and baseline flow velocities, and (2) systolic (S) to diastolic (D) flow were determined, using a proprietary software and by two independent observers. Importantly, the observed changes in coronary flow preceded LV dysfunction as evidenced by normal LV mass and fractional shortening (FS). The method was benchmarked against the current gold standard of coronary assessment, histopathology. The latter technique showed clear pathologic changes in the coronary artery in the form of peri-coronary fibrosis that correlated to the flow changes as assessed by echocardiography. The study underscores the value of using a non-invasive technique to monitor coronary circulation in mouse hearts. The method minimizes redundant use of research animals and demonstrates that advanced ultrasound-based indices, such as CFR and S/D ratios, can serve as viable diagnostic tools in a variety of investigational protocols including drug studies and the study of genetically modified strains.

Validation of high temporal resolution spiral phase velocity mapping of coronary artery blood flow against Doppler flow wire

Background The temporal pattern of coronary artery flow velocity through the cardiac cycle provides important information about coronary haemodynamics. The ‘gold standard’ for coronary artery velocity assessment is the Doppler flow wire which is inserted directly into the coronary artery under X-ray fluoroscopic guidance, which is invasive, uses ionising radiation and has a small but significant risk of serious complication. In this study, we perform an in vivo comparison of coronary blood flow velocities measured with breath-hold high temporal resolution spiral phase velocity mapping and Doppler flow wire measurements. Methods Breath-hold proximal coronary artery velocity maps were acquired in 5 left anterior descending (LAD) and 3 right coronary arteries (RCAs) in patients who had undergone invasive Doppler flow wire assessment as part of a clinical assessment. Acquisition parameters were: pixel size 1.4 × 1.4 mm (reconstructed to 0.7 ×0 .7 mm) ×8m m, true temporal resolution 19 ms, 1-1 water excitation (WE), 17 cardiac cycle breath-hold, velocity sensitivity 30-50cm/s, retrospective ECG gating (reconstructed 50 phases). Extraction of MR coronary artery blood flow velocitytime curves was performed using a custom MATLAB program which tracked the motion of the vessel over the cardiac cycle and corrected for the through-plane motion of the vessel using a region of adjacent tracked myocardium (LAD) or a region of surrounding epicardial fat (RCA) from a separately acquired fat-excitation acquisition. For each vessel, the mean through-plane motioncorrected MR velocities at all timepoints were plotted against the equivalent flow wire velocities. If necessary, the profiles were first time-shifted to take into account small differences in data triggering between the two techniques. The correlation between the two profiles was assessed using simple linear regression analysis. Results Figures 1 and 2 show example LAD and RCA studies. On average, the MR measured velocities were 66% less than the Flowire velocities (SD 9%, range: 50% - 78%). The correlation between the MR and flow wire data, however, was high, with R 2 values ranging from 0.6 - 0.95 in the 8 vessels studied (mean R 2 = .80).