Coronary Blood Flow Pattern Research Articles

Role of local coronary blood flow patterns and shear stress on the development of microvascular and epicardial endothelial dysfunction and coronary plaque.

The natural history of coronary atherosclerosis is complex and atherosclerotic plaques exhibit large morphologic and functional variability within the same individual as well as over time. The purpose of this article is to review the role of blood flow patterns and shear stress on the development of microvascular and epicardial endothelial dysfunction and atherosclerosis progression. Recent breakthroughs in cardiovascular imaging have facilitated in-vivo characterization of the anatomic and functional characteristics of atherosclerotic plaques and have highlighted the role of endothelial shear stress and epicardial and microvascular endothelial dysfunction in the natural history of coronary atherosclerosis. There is an important need to identify individual lesions which may progress to vulnerable plaque in order to provide early therapeutic management. Evaluation of endothelial shear stress, local blood flow patterns, epicardial and microvascular endothelial dysfunction, as well as their complex associations might indicate those patients who have microvascular endothelial dysfunction and increased risk for upstream epicardial endothelial dysfunction and plaque progression. Such high-risk patients could potentially be targeted for more intensive therapeutic strategies to prevent the progression of both microvascular and epicardial atherosclerotic manifestations.

Analysis of chaotic and noise processes in a fluctuating blood flow using the Allan variance technique

The aim of this work was to develop a novel technique for digital processing of Doppler ultrasound blood flow sensor data from noisy blood flow velocity waveforms. To evaluate the fluctuating blood flow parameters, various nonlinear dynamics methods and algorithms are often being used. Here, for identification of chaotic and noise components in a fluctuating coronary blood flow, for the first time the Allan variance technique was used. Analysis of different types of noises (White, Brownian, Flicker) was carried out and their strong correlation with fractality of time series (the Hurst exponent) was revealed. Based on a specialized software realizing the developed technique, numerical experiments with real clinical data were carried out. Recommendations for identification of noisy patterns of coronary blood flow in normal and pathological states were developed. The methodology gives us the possibility for the more detailed quantitative and qualitative analysis of a noisy fluctuating blood flow data.

Impact of thermodilution-derived coronary blood flow patterns after percutaneous coronary intervention on mid-term left ventricular remodeling in patients with ST elevation myocardial infarction.

We recently reported the coronary thermodilution curve can be evaluated by analyzing the thermodilution curve obtained from a pressure sensor/thermistor-tipped guidewire, and presence of a bimodal-shaped thermodilution curve following primary percutaneous coronary intervention (pPCI) in ST-segment elevation myocardial infarction (STEMI) patients was associated with worse outcomes. This study evaluated whether the bimodal-shaped thermodilution curve predicts left ventricular (LV) remodeling after STEMI. The coronary thermodilution curve patterns were evaluated for 75 patients treated by pPCI for their first STEMI using a pressure sensor/thermistor-tipped guidewire, and classified into the three groups according to the thermodilution curve shape: narrow unimodal (n=39), wide unimodal (n=26), and bimodal pattern (n=10). Echocardiography was performed at baseline and 6months after STEMI. LV remodeling was defined as a>20% increase in LV end-diastolic volumes (LVEDV). LVEDV at 6-month follow-up was greater in the bimodal group than in the other groups (p<0.001). The prevalence of LV remodeling was highest in the bimodal group than in the narrow and wide unimodal groups (60, 12, and 15%, respectively; p=0.003). Multivariate analysis revealed a bimodal-shaped thermodilution curve as an independent predictor of the prevalence of LV remodeling. A bimodal-shaped thermodilution curve is associated with LV remodeling after STEMI. This easily assessable coronary thermodilution curve pattern is useful to predict mid-term LV remodeling for STEMI patients at the catheterization laboratory.

Abstract 15416: Impact of Acute Hyperglycemia on Microvascular Damage and Long-term Clinical Outcomes in Patients With ST-elevation Myocardial Infarction

Introduction: We have recently reported the cause of microcirculatory damage after percutaneous coronary intervention (PCI) in ST-segment elevation myocardial infarction (STEMI) patients can be evaluated by analyzing the thermodilution-derived coronary blood flow pattern (CBFP), and only the capillary destruction pattern was associated with poor mid-term clinical outcomes. In this study, we extend our research on the contribution of acute hyperglycemia on microcirculatory damage and long-term clinical outcomes in STEMI patient. Methods: Ninety-seven consecutive STEMI patients undergoing primary PCI were prospectively enrolled. Using a pressure sensor/thermistor-tipped guidewire, CBFP was assessed from the thermodilution-curves immediately after successful PCI. All patients were classified into 3 groups according to the shape of thermodilution curve: no microvascular damaged group (n=47), arteriole microemboli group (n=33), or capillary destruction group (n=17). Blood glucose levels were measured on admission. Major adverse cardiac events (MACE) were defined as a composite of cardiac death, myocardial infarction, and heart failure rehospitalization within 3 years. Results: Mean admission glucose level was significantly higher in the capillary destruction group than in the microemboli and no microvascular damaged groups (259±134, 162±66, and 153±60 mg/dL, respectively, p&lt;0.0001). These findings were similar when the analysis was limited to non-diabetic patients. The incidence of MACE was also higher in the capillary destruction group compared with the microemboli and no microvascular damaged groups (71, 19, and 16%, respectively, p&lt;0.0001). On multivariate Cox regression analysis, the capillary destruction pattern was the independent predictor of MACE (hazard ratio, 9.41; 95%CI 2.28-38.8; p=0.001). In the multivariate logistic regression analysis, higher glucose level on admission remained as an independent risk factor of the capillary destruction pattern (per 10mg/dL increase, odds ratio, 1.10; 95%CI 1.10-1.22; p=0.002). Conclusions: Hyperglycemia on admission increases the risk of microvascular damage secondary to the capillary destruction and subsequent poor long-term clinical outcomes in STEMI patients.

Abstracts of the 2015 SCMR/EuroCMR Joint Scientific Sessions, February 4-7, 2015, Nice, France.

Background While blood flow in the majority of arteries peaks in systole, the rhythmic squeezing of the coronary arteries and microcirculation as the heart beats results in left anterior descending artery (LAD) flow being diastolicpredominant while for the right coronary artery (RCA), there is approximately equal flow in systole and diastole. These temporal flow patterns can provide important information on disease state. The aim of this study is to assess the inter-breath hold reproducibility of parameters of coronary haemodynamics using a high temporal resolution spiral phase velocity mapping technique and to compare automatic and manual analyses.

Abstract 19059: Thermodilution-derived Coronary Blood Flow Pattern Immediately After Coronary Intervention as a Predictor of Long-term Clinical Outcomes in Patients With ST-segment Elevation Myocardial Infarction

Background: We reported that coronary blood flow (CBF) can be evaluated by analyzing thermodilution curve that is measured with a single pressure sensor/thermistor-tipped guidewire in the cardiac catheterization laboratory during percutaneous coronary intervention (PCI). Bimodal shape of thermodilution curve was associated with microvascular damage and predictors of left ventricular functional recovery after ST-segment elevation myocardial infarction (STEMI). However it is unknown whether the bimodal shape of thermodilution curve predicts mortality and re-hospitalization for heart failure in long term period for patients experiencing STEMI. Methods: Between September 2009 and August 2012, 97 consecutive patients with a first STEMI were prospectively enrolled in this study. Using a pressure sensor/thermistor-tipped guidewire, CBF pattern was assessed from the thermodilution-curves after successful PCI at maximum hyperemia. CBF pattern was classified into 3 groups according to the shape of thermodilution curve: a narrow unimodal (a rapid fall and rise of temperature-time curves) (n=47), a wide unimodal (a gradual fall and rise of temperature-time curves) (n=33), or bimodal (two populations with valley deeper than 20% of peak temperature drop) (n=17). Major adverse cardiac events (MACE) were defined as cardiac death and/or heart failure re-hospitalization within this study period. Results: Median follow-up period was 2.4 years. Although patients in the narrow-unimodal group and the wide unimodal group had a significantly lower incidence of MACE, patients in bimodal group had a higher risk of MACE during this study period (71, 15, 21%, p&lt;0.001). Multivariate analysis revealed that bimodal shape of the thermodilution-curve was the only independent predictor of MACE after STEMI (hazard ratio, 8.38; 95% confidence interval, 2.13-33.00; P=0.0023). Conclusions: A bimodal shape of the thermodilution curve is associated with the poor long-term clinical outcomes. This easily assessable coronary flow pattern is useful in clinical risk stratification for STEMI patients in the cardiac catheterization laboratory immediately after PCI.

Letter by Echavarría-Pinto and Escaned Regarding Article, “Thermodilution-Derived Coronary Blood Flow Pattern Immediately After Coronary Intervention as a Predictor of Microcirculatory Damage and Midterm Clinical Outcomes in Patients With ST-Segment–Elevation Myocardial Infarction”

We read with great interest the article by Fukunaga et al1 entitled “Thermodilution-derived coronary blood flow pattern immediately after coronary intervention as a predictor of microcirculatory damage and midterm clinical outcomes in patients with ST-segment–elevation myocardial infarction.” We congratulate the authors for this interesting approach to assess myocardial damage during ST-segment–elevation myocardial infarction and would appreciate very much their views on several methodological aspects that seem to us of key importance for …

UNDERSTANDING THE PATHOPHYSIOLOGY OF APICAL BALLOONING SYNDROME, A STEP CLOSER!

The pathophysiology of Takotsubo's Cardiomyopathy (TC) remains unclear. Stress-induced epicardial coronary spasm or endothelial dysfunction induced myocardial stunning may be the mechanism for a distinctive left ventricular contraction pattern. We compared the patterns of coronary blood flow in

Thermodilution-Derived Coronary Blood Flow Pattern Immediately After Coronary Intervention as a Predictor of Microcirculatory Damage and Midterm Clinical Outcomes in Patients With ST-Segment–Elevation Myocardial Infarction

Despite a sufficient coronary blood flow after primary percutaneous coronary intervention for patients with ST-segment-elevation myocardial infarction; some patients have a poor outcome because of microcirculatory damage. This study evaluates whether the thermodilution-derived coronary blood flow parameters immediately after primary percutaneous coronary intervention predict early microvascular damage and midterm outcomes in patients with ST-segment-elevation myocardial infarction. Using a pressure sensor/thermistor-tipped guidewire, we measured the index of microcirculatory resistance at maximum hyperemia, and coronary blood flow pattern was assessed from the thermodilution curves after successful primary percutaneous coronary intervention in 88 patients with ST-segment-elevation myocardial infarction. Coronary blood flow pattern was classified into 3 groups according to the shape of thermodilution curve: a narrow unimodal (n=41), a wide unimodal (n=32), or bimodal (n=15). All patients had contrast-enhanced cardiac magnetic resonance scans within 2 weeks. The index of microcirculatory resistance values were significantly higher both in a wide unimodal and in a bimodal groups than in a narrow unimodal group (65±41 and 76±38 versus 20±9U; P<0.001). Bimodal group had higher prevalence of microvascular obstruction on contrast-enhanced cardiac magnetic resonance when compared with the other groups (100%, 78%, and 30%; P<0.001). Patients in bimodal group had a higher risk of death and heart failure rehospitalization at 6 months (73%, 6.3%, 7.3%; P<0.001). Multivariate analysis revealed that bimodal shape of the thermodilution curve was the only independent predictor of cardiac death at 6 months after ST-segment-elevation myocardial infarction (P<0.01). A bimodal shape of the thermodilution curve, which may indicate myocardial edema and consequent extrinsic compression of the capillary network, is associated with microcirculatory damage and poor midterm clinical outcomes rather than index of microcirculatory resistance value itself.

症例 成人例左冠動脈肺動脈起始異常症(Bland-White-Garland 症候群)の1例:ドプラ法による冠血行動態の検討

症例 成人例左冠動脈肺動脈起始異常症(Bland-White-Garland 症候群)の1例:ドプラ法による冠血行動態の検討

Mechanisms of right heart failure-A work in progress and a plea for failure prevention.

Mechanisms of right heart failure-A work in progress and a plea for failure prevention.

Thermodilution-Derived Coronary Blood Flow Pattern Immediately after Coronary Intervention As a Predictor of Microcirculatory Damage and Mid-Term Clinical Outcomes in Patients with ST-Segment Elevation Myocardial Infarction

Thermodilution-Derived Coronary Blood Flow Pattern Immediately after Coronary Intervention As a Predictor of Microcirculatory Damage and Mid-Term Clinical Outcomes in Patients with ST-Segment Elevation Myocardial Infarction

41 Reduced arterial wave reflection and enhanced LV relaxation contribute to warm-up angina

BackgroundThe mechanisms of the clinically observed phenomenon of reduced angina on second exertion, or warm-up angina, are poorly understood. This study compared changes in central haemodynamics, peripheral wave reflection and...

SU‐E‐I‐11: Extraction of Blood Flow Patterns and Calculation of Heart function Parameters in Dual Source CT Angiography

Purpose: A new approach is presented to extract the coronary artery blood flow patterns from the angiographic data and to calculate the parameter to evaluate the heart function. Methods: This method uses five patientsˈ coronary angiographic data. Firstly, use a ˈseedˈ method to extract the coronary artery in a completely automatic way. Secondly, acquire the blood flow patterns from the angiographic data with a ‘dynamic registration’ method and save the result image sequence as an AVI file. Finally, calculate the heart function parameter (velocity of blood flow) by frame counting method. Results: The accurate boundary of the coronary artery and the blood flow is clearly presented, and the velocity of blood flow is similar to the Dopller ultrasound measurement. Conclusions: This method is shown with good performance, particularly in modeling the blood flow patterns and calculation of heart function parameter. It provides not only an automatic, fast, real‐time and accurate method in precise diagnosis and treatment of coronary disease, but also a complementary criterion to evaluate the heart function, and then predict the recovery.

Relationship between Retrograde Coronary Blood Flow and the Extent of No-Reflow and Infarct Size in a Porcine Ischemia–Reperfusion Model

Recanalization of an infarct-related artery does not predictably reflect tissue reperfusion. We examined the relationship between coronary blood flow (CBF) pattern during reperfusion and infarcted (IA) and no-reflow (NR) area in a porcine ischemia-reperfusion model. The mid-left anterior descending artery of 18 pigs was occluded for 1h and reperfused for 2h. CBF during reperfusion was measured with a transit-time ultrasound flowmeter, while systemic arterial and left atrial pressures were monitored. IA and NR were measured with triphenyl tetrazolium chloride and thioflavin staining, respectively. In 13 pigs, early systolic retrograde CBF developed within the first 30min and persisted throughout reperfusion. No retrograde CBF was observed in five pigs. Mean retrograde CBF at 2h of reperfusion predicted a larger IA (r = 0.71; p = 0.001). Time-to-development of retrograde CBF was inversely related to IA (r = -0.55; p = 0.019) and NR (r = -0.62; p = 0.006). A larger IA (OR 1.12, 95% CI 1.01-1.24, p = 0.037) and NR (OR 1.09, 95% CI 1.01-1.18, p = 0.037) predicted the presence of retrograde CBF. Retrograde CBF during recanalization of the infarct-related artery predicts IA and NR and might be used as an index of successful reperfusion at the tissue level.

SU‐GG‐I‐185: Extraction of Blood Flow Patterns from Coronary Angiographic Data

Purpose: A new approach presented to extract the coronary artery and blood flow patterns from the angiographic data. Materials and methods: The method uses a sequence of coronary angiographic data. Firstly, the morphological erosion and the half‐thresholding are used for removing points except coronary area. Secondly, use morphological closing to join the gaps of the vessel. Thirdly, select the vessel points in the image sequence which is similar to the seed points. Make the seed points, which is also the whole skeleton of the vessel, continuously growing by the vessel points in the image sequence. Finally, compare the initial image sequence (grey value 0 to 1) with the seed image (binary image) which can bring the change of grey value in the vessel without the change of grey value in the background and save the result image sequence to AVI file. Result: The accurate boundary of the coronary artery is obtained and the blood flow is clearly present. Conclusion: The method is shown with better performance than current methods, particularly in modeling the flow pattern. And it's a very simple, fast and accurate method in precise diagnosis and treatment of patients. Key words: coronary artery, extraction, flow pattern, seed.

Ventral cardiac denervation increased right coronary arterial blood flow

Background Cardiac denervation accompanied with coronary artery bypass surgery has been widely performed for the treatment of vasospastic angina associated with atherosclerotic coronary artery disease. However, the effect of cardiac denervation on phasic coronary blood flow patterns of the left anterior descending coronary artery (LAD), left circumflex coronary artery (LCX) and right coronary artery (RCA) remains unknown. This study aimed to investigate the effect of cardiac denervation on phasic coronary blood flow patterns of the LAD, LCX and RCA. Methods Phasic coronary blood flow patterns were analyzed using three flow probes placed around the LAD, LCX and RCA with and without LAD stenosis. Ventral cardiac denervation (VCD) was performed in 8 pigs, and 16 pigs were used as control subjects. Autonomic activities before and after the VCD were quantified by wavelet analysis of heart rate variability. Results The mean LAD flow (34.4 ± 9.4 to 32.6 ± 7.1 ml/min, p = 0.638) and mean LCX flow (26.3 ± 10.2 to 27.2 ± 6.0 ml/min, p = 0.825) showed no significant change after VCD, while the mean RCA flow (31.3 ± 9.0 to 38.2 ± 11.2 ml/min, p = 0.003) significantly increased. The hemodynamic variables in the VCD group were well maintained after creation of LAD stenosis, while they deteriorated in the control group. The low- frequency components, high- frequency components and their ratio did not change after VCD. Conclusions VCD prevented the deterioration of cardiac function after creation of an LAD stenosis and resulted in an increase of the mean RCA flow. VCD did not affect autonomic nervous system activity.

Value of Coronary Blood Flow Pattern as a Predictor of Functional Recovery and Short-Term Left Ventricular Remodeling After Primary Coronary Angioplasty. A Transthoracic Doppler Study

Coronary blood flow measurement using a Doppler guidewire is the most sensitive way of detecting the no-reflow phenomenon following reperfusion of a myocardial infarction (MI). New high-frequency Doppler probes enable coronary blood flow velocity to be measured noninvasively. Our aims were to study the different patterns of left anterior coronary artery blood flow observed by transthoracic Doppler echocardiography, and to describe their association with functional recovery following reperfusion of an anterior MI. The study included 57 patients with a mean age of 60 years (range 30-85 years). An abnormal coronary blo:d flow pattern was defined as one in which there was a high peak diastolic velocity and a short deceleration time (i.e., < or = 500 ms). We compared the regional contractility, ventricular volumes, and left ventricular ejection fraction (LVEF) measured after 72 hours with those measured 1 month after MI. Overall, 31 patients (54%) had a normal coronary blood flow pattern (Group 1) and 26 (46%), an abnormal pattern (Group 2). After one month, regional contractility improved in Group-1 patients, as did LVEF, from 46.8 (8.6) to 52.6 (8.8)% (P=.002). In these patients, left ventricular volumes were unchanged. In contrast, regional contractility and LVEF remained unchanged in Group-2 patients whereas ventricular volumes increased, from 55.8 (12.9) to 62.9 (16.8) ml/m2 (P=.05), and from 32.2 (9.5) to 37.1 (14.9) ml/m2 (P< .05). Coronary blood flow pattern was the most important independent predictor of left ventricular remodeling, odds ratio =6.14 (95% CI, 1.56-24.17). Transthoracic Doppler echocardiographic assessment of coronary blood flow following reperfusion of an anterior myocardial infarction can be used to identify patients with microvascular damage who are progressing towards ventricular dilatation without recovery of myocardial function.

Phasic coronary blood flow pattern during a continuous flow left ventricular assist support

Continuous flow left ventricular assist devices (LVADs) have been introduced and tested as a bridge to heart transplantation, bridge to recovery, and destination therapy, and several studies have been conducted to assess the physiologic effects of continuous flow LVADs. However, the effect of reduced pulsatility on the phasic coronary blood flow pattern is unknown. The aim of this study was to investigate the phasic coronary blood flow patterns during continuous flow LVAD support. Phasic coronary blood flow patterns and hemodynamic data were analyzed using three flow probes placed around the left anterior descending coronary artery (LAD), left circumflex coronary artery (LCX), and the right coronary artery (RCA) in 16 pigs before and after initiating the LVAD support with or without creating LAD stenosis. The total coronary blood flow (TCBF, 112.8+/-31.4 mL/min) gradually decreased when the continuous flow LVAD support increased to 2.0 L/min (110.7+/-29.0 mL/min, P = 0.571), 2.5 L/min (103.7+/-26.1 mL/min, P = 0.079), and 3.0 L/min (101.5+/-27.2 mL/min, P = 0.027) because of decreases in LAD flow and LCX flow. LVAD support caused decrease in systolic and peak systolic LAD flow, LCX flow, and RCA flow, whereas diastolic RCA flow increased. In the presence of LAD stenosis, the TCBF (97.7+/-36.1 mL/min) decreased when the continuous flow LVAD support increased to 2.0 L/min (83.9+/-22.1 mL/min, P = 0.029), 2.5 L/min (83.2+/-25.2 mL/min, P = 0.012), and 3.0 L/min (87.6+/-23.4 mL/min, P = 0.005) because of decreases in LCX flow. Use of a continuous flow LVAD decreased TCBF, LAD flow, and LCX flow secondary to reduced systolic LAD flow and LCX flow, and decreased TCBF and LCX flow in the presence of LAD stenosis. These findings are potentially relevant to understanding the physiology of myocardial blood perfusion during continuous flow LVAD support especially in patients with coronary artery disease.

The Effects of Pulsatile versus Non-Pulsatile Extracorporeal Circulation on the Pattern of Coronary Artery Blood Flow during Cardiac Arrest

In sudden cardiac arrest, the effective maintenance of coronary artery blood flow is of paramount importance for myocardial preservation as well as cardiac recovery and patient survival. The purpose of this study was to directly compare the effects of pulsatile versus non-pulsatile circulation to coronary artery flow and myocardial preservation in a cardiac arrest condition. A cardiopulmonary bypass circuit was constructed in a ventricular fibrillation model using fourteen Yorkshire swine weighing 25-35 kg each. The animals were randomly assigned to group I (n=7, non-pulsatile centrifugal pump) or group II (n=7, pulsatile T-PLS pump). Extracorporeal circulation was maintained for two hours at a pump flow of 2 L/min. The left anterior descending coronary artery flow was measured with an ultrasonic coronary artery flow measurement system at baseline (before bypass) and at every 20 minutes after bypass. Serologic parameters were collected simultaneously at baseline, 1 hour, and 2 hours after bypass in the systemic arterial and coronary sinus venous blood. The Mann-Whitney U test of STATISTICA 6.0 was used to determine intergroup significances using a p value of <0.05. The resistance index of the coronary artery was lower in group II and the difference was significant at 40 min, 80 min, 100 min and 120 min (p<0.05). The mean velocity of the coronary artery was higher in group II throughout the study, and the difference was significant from 20 min after starting the pump (p<0.05). The coronary artery blood flow was higher in group II throughout the study, and the difference was significant from 40 min to 120 min (p<0.05) except at 80 min. Serologic parameters showed no differences between the groups at 1 hour and 2 hours after bypass in the systemic and coronary sinus blood (p=NS). In the cardiac arrest condition, pulsatile extracorporeal circulation provides more blood flow, higher flow velocity and less resistance to coronary artery than non-pulsatile circulation.