Assessment of the relative distribution of myocardial flow with myocardial perfusion imaging （MPI） is meth- odologically limited to predict the presence or absence of flow-limited coronary artery disease （CAD）. Th...Assessment of the relative distribution of myocardial flow with myocardial perfusion imaging （MPI） is meth- odologically limited to predict the presence or absence of flow-limited coronary artery disease （CAD）. This limi- tation may often occur, when obstructive lesions involve multiple epicardial coronary arteries or disease-related disturbances of the coronary circulation coexist at the microvascular level. Non-invasive assessment of myocar- dial blood flow in absolute units with position emission tomography （PET） has been positioned as the solution to improve CAD diagnosis and prediction of patient outcomes associated with risks for cardiac events. This article reviews technical and clinical aspects of myocardial blood flow quantitation with PET and discusses the practical consideration of this approach toward worldwide clinical utilization.展开更多
BACKGROUND Acute myocardial infarction(AMI)is a leading cause of mortality.Early reperfusion to restore blood flow is crucial to successful treatment.In the current reperfusion regimen,an increasing number of patients...BACKGROUND Acute myocardial infarction(AMI)is a leading cause of mortality.Early reperfusion to restore blood flow is crucial to successful treatment.In the current reperfusion regimen,an increasing number of patients have benefited from direct percutaneous coronary intervention(PCI).In order to understand whether there is a correlation between the components of coronary thrombosis and the absence of reflow or slow blood flow after coronary stent implantation in direct PCI,we collected data on direct PCI cases in our hospital between January 2016 and November 2018.AIM To investigate the correlation between intracoronary thrombus components and coronary blood flow after stent implantation in direct PCI in AMI.METHODS We enrolled 154 patients(85 male and 69 female,aged 36–81 years)with direct PCI who underwent thrombus catheter aspiration within<3,3–6 or 6–12 h of onset of AMI between January 2016 and November 2018.The thrombus was removed for pathological examination under a microscope.The patients of the three groups according to the onset time of AMI were further divided into those with a white or red thrombus.The thrombolysis in myocardial infarction(TIMI)blood flow after stent implantation was recorded based on digital subtraction angiography during PCI.The number of patients with no-reflow and slow blood flow in each group was counted.Statistical analysis was performed based on data such as onset time,TIMI blood flow.RESULTS There were significant differences in thrombus components between the patients with acute ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction(P<0.01).In the group with PCI<3 h after onset of AMI,there was no significant difference in the incidence of no-reflow and slow-flow between the white and red thrombus groups.In the groups with PCI 3-6 and 6-12 h after onset of AMI,there was a significant difference in the incidence of no-reflow and slow-flow between the white and red thrombus groups(P<0.01).There was a significant correlation between the onset time of AMI and the occurrences of no-reflow and slow blood flow during PCI(P<0.01).CONCLUSION In direct PCI,the onset time of AMI and color of coronary thrombus are often used to predict whether there will be no reflow or slow blood flow after stent implantation.展开更多
Objective:To investigate the effects of different doses of ticagrelor on coronary blood flow, inflammatory response and myocardial enzyme spectrum in patients with acute myocardial infarction.Methods: A total of 180 p...Objective:To investigate the effects of different doses of ticagrelor on coronary blood flow, inflammatory response and myocardial enzyme spectrum in patients with acute myocardial infarction.Methods: A total of 180 patients with acute myocardial infarction who were treated in our hospital between December 2015 and March 2017 were reviewed and divided into the routine dose group (n=87) who accepted routine dose of ticagrelor therapy and loading dose group (n=93) who accepted loading dose of ticagrelor therapy. The differences in coronary blood flow, inflammatory response and myocardial enzyme spectrum were compared between the two groups before and after treatment.Results: Immediately after admission, there was no statistically significant difference in the coronary blood flow levels, inflammatory response and myocardial enzyme spectrum contents between the two groups. At 24 h after percutaneous coronary intervention (PCI), the coronary blood flow parameters SPV, DPV and CFVR levels in loading dose group were higher than those in routine dose group;serum inflammatory factors PCT, IL-6 and CRP contents were lower than those of routine dosage group;myocardial enzyme spectrum indexes cTnⅠ, LDH, HBDH and MB contents were lower than those of routine dose group.Conclusion: Loading dose of ticagrelor therapy before PCI can effectively optimize the coronary blood flow after PCI, reduce the systemic inflammatory response and protect the myocardial function in patients with acute myocardial infarction.展开更多
Objectives Nitroglycerine (NTG) enhances coronary blood flow to compromised myocardium is important in relieving ischemia. However, the mechanism for this increase in myocardial blood flow (MBF) is not well defined. I...Objectives Nitroglycerine (NTG) enhances coronary blood flow to compromised myocardium is important in relieving ischemia. However, the mechanism for this increase in myocardial blood flow (MBF) is not well defined. In small vessels and capillaries, relative blood viscosity plays a very important role in determining myocardial vascular resistance (MVR). MVR reduce is due partly to the increase in negative charge of erythrocyte surface. We therefore hypothesized that the enhancement of nutrient blood flow to zones of myocardial ischemia during NTG is partly secondary to reduced MVR and blood flow viscosity. The latter is affected by the negative charge of erythrocyte surface. Methods 6 dogs with LAD flow-limiting stenosis (group 1) and 6 dogs with LAD flow-limiting stenosis and LCx occmusion (group 2) were studied. At baseline and during intracoronary infusions of NTG (0.3-0.6 μg·kg-1·min-1), hemodynamics, MBF (mL·min-1·g-1), whole blood viscosity (WBη, mPa. S), elongation index (EI), eletrophoretic mobility of erythocytes (EME, [μ.s-1)/(V.cm-1)]) and percent wall thickening (%WT) were determined. MVR was calculated using driving pressure/MBF. Results As compared to baseline, no changes in hemodynamics were seen during NTG. MBF increased and MVR decreased significantly in normal bed, the central 25% and the entire of stenosed bed (P<0.05), with a decrease in WBη in both group 1 and group 2 dogs (18.6±9.7 % and 19.2±14.5 %, respectively). However, the % decrease in WBη was proportioned to the % increase in MBF or the % decrease in MVR only in the central 25% of stenosed bed (r=0.87, P<0.001), but not in the entire stenosed bed and normal bed. EI did not show statistically significant differences between during NTG and at baseline, but EME did increase. And the % decrease in WBη during NTG was related to the % increase in EME (r=0.83, P=0.01). Conclusions NTG reduced myocardial vascular resistance and blood viscosity due to the change of negative charge of erythrocyte surface may, in part, be the mechanism of the enhancement of nutrient blood flow to zones of myocardial ischemia. These results provide additional insights into the complex anti-ischemic effects of NTG.展开更多
Background Myocardial blood flow(MBF) can be quantified with myocardial contrast echocardiography (MCE) during a venous infusion of microbubble. A minimal MBF is required to maintain cell membrane integrity and myocar...Background Myocardial blood flow(MBF) can be quantified with myocardial contrast echocardiography (MCE) during a venous infusion of microbubble. A minimal MBF is required to maintain cell membrane integrity and myocardial viability in ischemic condition. Thus, we hypothesized that MCE could be used to assess myocardial viability by the determination of MBF. Methods and ResultsMCE was performed at 4 hours after ligation of proximal left anterior descending coronary artery in 7 dogs with constant venous infusions of microbubbles. The video intensity versus pulsing interval plots derived from each myocardial pixel were fitted to an exponential function: y=A(1-e-βt), where y is Ⅵ at pulsing interval t, A reflects microvascular cross - sectional area (or myocardial blood volume), and βreflects mean myocardial microbubble velocity. The product of A·β represents MBF. MBF was also obtained by ra-diolabeled microsphere method servered as reference. MBF derived by radiolabeled microsphere - method in the regions of normal, ischemia and infarction was 1.5+0.3, 0.7+0.3, 0. 3+0. 2 mL @ min-1@ g-1 respectively. The product of A·β obtained by MCE in those regions was 52. 46±15. 09, 24. 36±3. 89, 3. 74 ±3. 80 respectively. There was good correlation between normalized MBF and the normalized A·β ( r = 0. 81, P=0. 001). Conclusions MCE has an ability to determine myocardial viability in myocardial infarction canine model.展开更多
Changes in intramyocardial tissue pressure modulate the relationship between coronary pressure and flow during the cardiac cycle. The present study compared the relation between measured and calculated diastolic suben...Changes in intramyocardial tissue pressure modulate the relationship between coronary pressure and flow during the cardiac cycle. The present study compared the relation between measured and calculated diastolic subendocardial tissue pressure and coronary pressure at zero flow in anesthetized dogs after modulation of either coronary sinus (i.e. Fogarty catheter) or left ventricular intracavity (i.e. volume loading) pressure. Experiments were conducted in anesthetized, instrumented dogs;coronary pressure flow relations were constructed during pharmacologic vasodilatation and intramyocardial tissue pressure was measured using micromanometer pressure sensors. Elevated coronary sinus pressures did not affect subendocardial pressure-flow relations signifying that diastolic tissue pressure within this layer is the effective coronary back pressure. Higher left ventricular intracavity pressure did not affect either diastolic subendocardial tissue pressure or pressure flow relations within this layer. Results show a direct linear relation (y = 1.106x - 0.652;r2 = 0.59. P = 0.001) between measured and calculated diastolic subendocardial tissue pressure and coronary pressure at zero-flow over a wide range of pressures after either LV systemic or coronary sinus pressure modulation. Knowledge of back pressure in the subendocardium is useful for the evaluation of efficacy of cardiac interventions on myocardial perfusion particularly at the level of the microcirculation.展开更多
文摘Assessment of the relative distribution of myocardial flow with myocardial perfusion imaging （MPI） is meth- odologically limited to predict the presence or absence of flow-limited coronary artery disease （CAD）. This limi- tation may often occur, when obstructive lesions involve multiple epicardial coronary arteries or disease-related disturbances of the coronary circulation coexist at the microvascular level. Non-invasive assessment of myocar- dial blood flow in absolute units with position emission tomography （PET） has been positioned as the solution to improve CAD diagnosis and prediction of patient outcomes associated with risks for cardiac events. This article reviews technical and clinical aspects of myocardial blood flow quantitation with PET and discusses the practical consideration of this approach toward worldwide clinical utilization.
文摘BACKGROUND Acute myocardial infarction(AMI)is a leading cause of mortality.Early reperfusion to restore blood flow is crucial to successful treatment.In the current reperfusion regimen,an increasing number of patients have benefited from direct percutaneous coronary intervention(PCI).In order to understand whether there is a correlation between the components of coronary thrombosis and the absence of reflow or slow blood flow after coronary stent implantation in direct PCI,we collected data on direct PCI cases in our hospital between January 2016 and November 2018.AIM To investigate the correlation between intracoronary thrombus components and coronary blood flow after stent implantation in direct PCI in AMI.METHODS We enrolled 154 patients(85 male and 69 female,aged 36–81 years)with direct PCI who underwent thrombus catheter aspiration within<3,3–6 or 6–12 h of onset of AMI between January 2016 and November 2018.The thrombus was removed for pathological examination under a microscope.The patients of the three groups according to the onset time of AMI were further divided into those with a white or red thrombus.The thrombolysis in myocardial infarction(TIMI)blood flow after stent implantation was recorded based on digital subtraction angiography during PCI.The number of patients with no-reflow and slow blood flow in each group was counted.Statistical analysis was performed based on data such as onset time,TIMI blood flow.RESULTS There were significant differences in thrombus components between the patients with acute ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction(P<0.01).In the group with PCI<3 h after onset of AMI,there was no significant difference in the incidence of no-reflow and slow-flow between the white and red thrombus groups.In the groups with PCI 3-6 and 6-12 h after onset of AMI,there was a significant difference in the incidence of no-reflow and slow-flow between the white and red thrombus groups(P<0.01).There was a significant correlation between the onset time of AMI and the occurrences of no-reflow and slow blood flow during PCI(P<0.01).CONCLUSION In direct PCI,the onset time of AMI and color of coronary thrombus are often used to predict whether there will be no reflow or slow blood flow after stent implantation.
文摘Objective:To investigate the effects of different doses of ticagrelor on coronary blood flow, inflammatory response and myocardial enzyme spectrum in patients with acute myocardial infarction.Methods: A total of 180 patients with acute myocardial infarction who were treated in our hospital between December 2015 and March 2017 were reviewed and divided into the routine dose group (n=87) who accepted routine dose of ticagrelor therapy and loading dose group (n=93) who accepted loading dose of ticagrelor therapy. The differences in coronary blood flow, inflammatory response and myocardial enzyme spectrum were compared between the two groups before and after treatment.Results: Immediately after admission, there was no statistically significant difference in the coronary blood flow levels, inflammatory response and myocardial enzyme spectrum contents between the two groups. At 24 h after percutaneous coronary intervention (PCI), the coronary blood flow parameters SPV, DPV and CFVR levels in loading dose group were higher than those in routine dose group;serum inflammatory factors PCT, IL-6 and CRP contents were lower than those of routine dosage group;myocardial enzyme spectrum indexes cTnⅠ, LDH, HBDH and MB contents were lower than those of routine dose group.Conclusion: Loading dose of ticagrelor therapy before PCI can effectively optimize the coronary blood flow after PCI, reduce the systemic inflammatory response and protect the myocardial function in patients with acute myocardial infarction.
文摘Objectives Nitroglycerine (NTG) enhances coronary blood flow to compromised myocardium is important in relieving ischemia. However, the mechanism for this increase in myocardial blood flow (MBF) is not well defined. In small vessels and capillaries, relative blood viscosity plays a very important role in determining myocardial vascular resistance (MVR). MVR reduce is due partly to the increase in negative charge of erythrocyte surface. We therefore hypothesized that the enhancement of nutrient blood flow to zones of myocardial ischemia during NTG is partly secondary to reduced MVR and blood flow viscosity. The latter is affected by the negative charge of erythrocyte surface. Methods 6 dogs with LAD flow-limiting stenosis (group 1) and 6 dogs with LAD flow-limiting stenosis and LCx occmusion (group 2) were studied. At baseline and during intracoronary infusions of NTG (0.3-0.6 μg·kg-1·min-1), hemodynamics, MBF (mL·min-1·g-1), whole blood viscosity (WBη, mPa. S), elongation index (EI), eletrophoretic mobility of erythocytes (EME, [μ.s-1)/(V.cm-1)]) and percent wall thickening (%WT) were determined. MVR was calculated using driving pressure/MBF. Results As compared to baseline, no changes in hemodynamics were seen during NTG. MBF increased and MVR decreased significantly in normal bed, the central 25% and the entire of stenosed bed (P<0.05), with a decrease in WBη in both group 1 and group 2 dogs (18.6±9.7 % and 19.2±14.5 %, respectively). However, the % decrease in WBη was proportioned to the % increase in MBF or the % decrease in MVR only in the central 25% of stenosed bed (r=0.87, P<0.001), but not in the entire stenosed bed and normal bed. EI did not show statistically significant differences between during NTG and at baseline, but EME did increase. And the % decrease in WBη during NTG was related to the % increase in EME (r=0.83, P=0.01). Conclusions NTG reduced myocardial vascular resistance and blood viscosity due to the change of negative charge of erythrocyte surface may, in part, be the mechanism of the enhancement of nutrient blood flow to zones of myocardial ischemia. These results provide additional insights into the complex anti-ischemic effects of NTG.
基金This work was supported in part by grants from thescience and technology foundation of China(39870329).
文摘Background Myocardial blood flow(MBF) can be quantified with myocardial contrast echocardiography (MCE) during a venous infusion of microbubble. A minimal MBF is required to maintain cell membrane integrity and myocardial viability in ischemic condition. Thus, we hypothesized that MCE could be used to assess myocardial viability by the determination of MBF. Methods and ResultsMCE was performed at 4 hours after ligation of proximal left anterior descending coronary artery in 7 dogs with constant venous infusions of microbubbles. The video intensity versus pulsing interval plots derived from each myocardial pixel were fitted to an exponential function: y=A(1-e-βt), where y is Ⅵ at pulsing interval t, A reflects microvascular cross - sectional area (or myocardial blood volume), and βreflects mean myocardial microbubble velocity. The product of A·β represents MBF. MBF was also obtained by ra-diolabeled microsphere method servered as reference. MBF derived by radiolabeled microsphere - method in the regions of normal, ischemia and infarction was 1.5+0.3, 0.7+0.3, 0. 3+0. 2 mL @ min-1@ g-1 respectively. The product of A·β obtained by MCE in those regions was 52. 46±15. 09, 24. 36±3. 89, 3. 74 ±3. 80 respectively. There was good correlation between normalized MBF and the normalized A·β ( r = 0. 81, P=0. 001). Conclusions MCE has an ability to determine myocardial viability in myocardial infarction canine model.
文摘Changes in intramyocardial tissue pressure modulate the relationship between coronary pressure and flow during the cardiac cycle. The present study compared the relation between measured and calculated diastolic subendocardial tissue pressure and coronary pressure at zero flow in anesthetized dogs after modulation of either coronary sinus (i.e. Fogarty catheter) or left ventricular intracavity (i.e. volume loading) pressure. Experiments were conducted in anesthetized, instrumented dogs;coronary pressure flow relations were constructed during pharmacologic vasodilatation and intramyocardial tissue pressure was measured using micromanometer pressure sensors. Elevated coronary sinus pressures did not affect subendocardial pressure-flow relations signifying that diastolic tissue pressure within this layer is the effective coronary back pressure. Higher left ventricular intracavity pressure did not affect either diastolic subendocardial tissue pressure or pressure flow relations within this layer. Results show a direct linear relation (y = 1.106x - 0.652;r2 = 0.59. P = 0.001) between measured and calculated diastolic subendocardial tissue pressure and coronary pressure at zero-flow over a wide range of pressures after either LV systemic or coronary sinus pressure modulation. Knowledge of back pressure in the subendocardium is useful for the evaluation of efficacy of cardiac interventions on myocardial perfusion particularly at the level of the microcirculation.
