Chronotropic doses of dobutamine have been shown to increase transmural WT, even in perfusion beds subtended by coronary stenoses that range from 30% to 80% in diameter (8). If the stenosis is more severe or if higher doses of dobutamine are used, WT becomes abnormal (2). Transmural myocardial blood flow responses, however, are different, with decreases in myocardial blood flow observed even in milder non-flow limiting stenoses (2). As the stenosis becomes more severe, a marked decrease in subendocardial blood flow has been observed (9-11), with a marked decrease in endocardial/epicardial flow ratios. In this study, RTMCE detected this decrease in endocardial to epicardial blood flow abnormality in 45 of the 55 patients with LAD stenoses ,50%.. Another pertinent pharmacologic property of dobutamine is its ability to recruit the subepicardial layers to thicken. The subendocardium is responsible for over 40% of WT under resting conditions (12,13), and thus resting WT might be abnormal even when ...
CM Webb, JG McNeill, GMC Rosano, P Coluns; Testosterone Increases Coronary Blood flow in Men with Coronary Artery Disease. Clin Sci (Lond) 1 February 1998; 94 (s38): 5P. doi: https://doi.org/10.1042/cs094005Pa. Download citation file:. ...
Background. Experimental studies on the effects of alpha2-adrenoceptors on regional coronary blood flow in normal and ischemic myocardium are highly controversial. A beneficial effect on regional ischemic myocardium has been demonstrated in different animal preparations with either alpha2-adrenoceptor blockade or stimulation. Animal studies also demonstrated that postsynaptic alpha2-adrenoceptors mediate vasoconstriction in coronary and femoral vascular beds. The aims of the study were 1) to investigate the effects of regional alpha2-adrenoceptor stimulation on regional coronary blood flow in subjects with angiographically normal coronary arteries, 2) to assess the effect of alpha2-adrenoceptor blockade on coronary circulation in control subjects, and 3) to examine the influence of atherosclerosis on coronary blood flow response to alpha2-adrenoceptor blockade. Methods and Results. The effect of regional administration of BHT 933 (a selective alpha2-adrenoceptor agonist) was studied in eight ...
TY - JOUR. T1 - The role of capillaries in determining coronary blood flow reserve. T2 - Implications for stress-induced reversible perfusion defects. AU - Kaul, Sanjiv. N1 - Funding Information: From the Cardiovascular Imaging Center, Cardiovascular Division, University of Virginia School of Medicine, Charlottesville, Va. Supported in part by grants (3R01-HL48890, RO1-HL65704, and RO1-HL66034) from the National Institutes of Health, Bethesda, Md. Reprint requests: Sanjiv Kaul, MD, Cardiovascular Division, Box 158, Medical Center, University of Virginia, Charlottesville, VA 22908; [email protected] J Nucl Cardiol 2001;8:694-700. Copyright © 2001 by the American Society of Nuclear Cardiology. 1071-3581/2001/$35.00 + 0 43/1/119690 doi:10.1067/mnc.2001.119690. PY - 2001. Y1 - 2001. N2 - In summary, unlike tracers such as radiolabeled microspheres that are trapped in the microcirculation (and therefore have a 100% extraction fraction), the uptake of diffusible tracers is determined by the status of ...
Previous reports have indicated that hypertensive patients who have angina-like chest pain and normal coronary arteriograms have reduced coronary flow velocity reserve (CFVR) levels. In addition, elevated plasma endothelin-1 (ET-1) levels have been reported to be associated with microvascular angina. The purpose of this study was to evaluate the plasma ET-1 levels and CFVR in patients with chest pain but without coronary artery disease (CAD). A total of 66 patients were included in this study. CAD was ruled out by exercise stress test or coronary angiogram. Plasma ET-1 and CFVR measurements were performed in patients with (n=35) and without (n=31) a history of angina-like chest pain. CFVR was measured using adenosine-triphosphate stress transthoracic Doppler echocardiography. The mean ET-1 level was significantly higher and the CFVR was significantly lower in patients in the symptomatic group than in those in the asymptomatic group (ET-1: 3.85±1.24 pg/ml vs. 2.98±1.27 pg/ml, CFVR: 2.26±0.48 vs. 2.77
Coronary flow velocity reserve (CFVR) measured by transthoracic Doppler echocardiography of the LAD is used to assess microvascular function but validation studies in clinical settings are lacking. We aimed to assess feasibility, reproducibility and agreement with myocardial flow reserve (MFR) measured by PET in overweight and obese patients. Participants with revascularized coronary artery disease were examined by CFVR. Subgroups were examined by repeated CFVR (reproducibility) or Rubidium-82-PET (agreement). To account for time variation, results were computed for scans performed within a week (1-week) and for all scans regardless of time gap (total) and to account for scar tissue for patients with and without previous myocardial infarction (MI). Eighty-six patients with median BMI 30.9 (IQR 29.4-32.9) kg × m−2 and CFVR 2.29 (1.90-2.63) were included. CFVR was feasible in 83 (97 %) using a contrast agent in 14 %. For reproducibility overall (n = 21) limits of agreement (LOA) were (−0.75;0.71),
The effect of a new coronary vasodilator (Persantin), which produces a marked increase in coronary blood flow (up to 159 per cent in normal animals) without increasing cardiac contractility or cardiac work, has been studied in the experimental animal. This is associated with a marked decrease in coronary resistance. There is an increase in the coronary venous oxygen content and a decrease in the coronary A-V oxygen difference; the cardiac output is only slightly affected. Increase in the coronary blood flow has also been observed in dogs in which coronary in sufficiency has been produced by coronary ligation and by narrowing of the lumen of the coronary artery by the application of casein rings. This was accompanied by no significant increase in cardiac work.. ...
Relief of the coronary obstruction by thrombolysis or percutaneous catheter-based intervention and restoration of normal flow in the culprit artery has been the goal of therapy in patients with acute MI. This analysis shows, however, that acute MI slows flow not only in the culprit artery, but also in the nonculprit artery by 45%. Culprit and nonculprit artery flows were linked, and relief of the residual stenosis in the culprit artery restored flow to the culprit artery, which was the same as in the nonculprit arteries (both 30 frames). Although improved post-PTCA, both culprit and nonculprit artery flows were still 45% slower than normal (21 frames). Multiple variables were associated with slower nonculprit artery flow: slower flow in the associated culprit artery, a larger territory infarcted (e.g., larger diameter culprit arteries with a larger percent of the culprit vessel distal to the stenosis, the absence of collaterals, LAD as the culprit artery), tighter stenoses within the nonculprit ...
To examine the influence of preexistent diabetes mellitus on left ventricular performance and coronary blood flow responses to acute ischemia, mild normoglycemic diabetes was induced in nine mongrel dogs after three doses of alloxan, (20 mg/kg, iv), at monthly intervals. Hemodynamic measurements and coronary blood flow (85Kr clearance) were obtained before and after the onset of ischemia. This was produced by occlusion of the proximal left anterior descending coronary artery via a balloon-type catheter in nine intact anesthetized diabetic dogs and 10 nondiabetic dogs. During the 1st hour of ischemia in the diabetic group, the end-diastolic pressure rose from 7 +/- 1.1 (mean +/- SE) mm Hg to 23.8 +/- 2.3 without a significant increase of end-diastolic volume. In controls end-diastolic pressure rose from 8.6 +/- 1.1 mm Hg to 15.3 +/- 1.4, and end-diastolic volume was significantly increased, so that the ratio of end-diastolic pressure and volume was significantly higher in the diabetic group (P ...
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Apart from evaluating the physiological significance of epicardial stenoses, intracoronary Doppler has become an important tool in patients with suspected microvascular disease. Recent studies report an impaired coronary flow reserve in patients with diabetes mellitus, hypertension and smoking (11,19-22). These findings are attributed to abnormalities in coronary vasomotion. It has been proposed that a coronary flow reserve of less than 2.5 (23) and a CFVR of less than 2.24 (14) in the absence of significant epicardial stenosis is a sign of microvascular dysfunction. Categorizing women in this study according to the cut-off value for CFVR of 2.24 revealed that women with suspected microvascular dysfunction have a significantly increased bAPV, and systolic blood pressure. As these factors may, in part, contribute to the reduction of CFVR, the use of traditional CFVR as an indicator of microvascular dysfunction may not sufficiently discriminate between factors affecting vasodilator reserve and ...
article{2286a0f7-5934-41f8-aed8-94b7a8b75a40, abstract = {Recent studies indicate a severely reduced coronary flow reserve (CFR) in neonates with congenital heart disease. The significance of these studies remains debatable, as the ability of the anatomically normal neonatal heart to increase coronary flow is currently unknown. This study was designed to establish normal values for CFR in newborns after administration of adenosine [pharmacologic CFR (pCFR)] and as induced by acute hypoxemia (reactive CFR). Thirteen mechanically ventilated newborn lambs were studied. Coronary flow velocities were measured in the proximal left anterior descending coronary artery before and after adenosine injection (140 and 280 mug/kg i.v.) using an intracoronary 0.014-in Doppler flow-wire. Measurements were made at normal oxygen saturation (Sao(2)) and during progressive hypoxemia induced by lowering the fraction of inspired oxygen. CFR was defined as the ratio of hyperemic to basal average peak flow velocity. In ...
C Newman, D Hackett, H El-Tamimi, A Maseri, G Davies; Acetylcholine Has Dose-Dependent Bimodal Effects on Coronary Blood Flow in Man. Clin Sci (Lond) 1 January 1988; 74 (s18): 45P. doi: https://doi.org/10.1042/cs074045P. Download citation file:. ...
5-hydroxytryptamine (5-HT)-induced coronary artery responses have both vasoconstriction and vasorelaxation components. The vasoconstrictive effects of 5-HT have been well studied while the mechanism(s) of how 5-HT causes relaxation of coronary arteries has been less investigated. In isolated rat hearts, 5-HT-induced coronary flow increases are partially resistant to the nitric oxide synthase inhibitor Nω-Nitro-L-arginine methyl ester (L-NAME) and are blocked by 5-HT7 receptor antagonists. In the present study, we investigated the role of 5-HT7 receptor in 5-HT-induced coronary flow increases in isolated rat hearts in the absence of L-NAME, and we also evaluated the involvement of endothelium-derived hyperpolarizing factor (EDHF) in 5-HT-induced coronary flow increases in L-NAME-treated hearts with the inhibitors of arachidonic acid metabolism and the blockers of Ca2+-activated K+ channels. In isolated rat hearts, 5-HT and the 5-HT7 receptor agonist 5-carboxamidotryptamine induced coronary flow
Myocardial perfusion imaging (MPI), using single photon emission computed tomography (SPECT) is a validated method for detecting coronary artery disease. Transthoracic Doppler echocardiography (TTDE) of flow at rest and during adenosine provocation has previously been evaluated in selected patient groups. We therefore wanted to compare the diagnostic ability of TTDE in the left anterior descending coronary artery (LAD) to that of MPI in an unselected population of patients with chest pain referred for MPI. Our hypothesis was that TTDE with high accuracy would identify healthy individuals and exclude them from the need for further studies, enabling invasive investigations to be reserved for patients with a high probability of disease. Sixty-nine patients, 44 men and 25 women, age 61 ± 10 years (range 35-82), with a clinical suspicion of stress induced myocardial ischemia, were investigated. TTDE was performed at rest and during adenosine stress for myocardial scintigraphy. We found that coronary flow
This study was designed to examine the relationship between epicardial ST change (EpST) and regional myocardial blood flow (RMBF) following coronary occlusion and extent of myocardial infarction (MI) in awake dogs. Fifteen min and two hr after coronary occlusion simultaneous measurements of EpST and RMBF were made. Six days later histologic MI and RMBF were determined in transmural myocardial samples from each electrode site. Greatest ST elevation occurred at sites of greatest ischemia and MI. However, 15 min after occlusion 29% of sites with greater than 50% MI and 39% of sites with greater than 50% reduction in RMBF did not demonstrate ST elevation greater than 2 mV. There were poor correlations between EpST and MI (r = 0.59) and RMBF (r = 0.57). Comparable relationships were observed two hr after occlusion. In the present study, there were not close quantitative or qualitative relationships between EpST and MI or RMBF. A good correlation was observed between RMBF at two hr and MI (r = 0.89). ...
There is intense controversy as to the mechanisms underlying chronic but reversible left ventricular (LV) ischemic dysfunction. The aim of this study was to investigate the physiology underlying this condition in a canine model of noninfarcted collateral-dependent myocardium. METHODS: Six mongrel dogs were instrumented with ameroid constrictors on the left circumflex and right coronary arteries and a partial occluder on the left anterior descending coronary artery. The animals were followed up for 6 mo. Every 6 wk, measurements of regional wall thickening (M-mode echo), myocardial blood flow ((13)N-ammonia PET), oxygen consumption ((11)C-acetate PET), and glucose uptake ((18)F-FDG PET) were obtained. After 6 mo, myocardial blood flow reserve (during adenosine infusion) and regional contractile reserve (during infusion of a low dose of dobutamine) were also investigated. RESULTS: Following ameroid implantation, regional thickening decreased in the posterior wall (to 34% +/- 13% of baseline; P , ...
Spontaneously hypertensive rats (SHR) demonstrate an elevated minimal coronary vascular resistance by the seventh month of age. In an attempt to determine the role of long-standing hypertension in the etiological process of the elevated minimal coronary vascular resistance, we treated SHR and normotensive Wistar-Kyoto rats (WKY) with the vasodilator hydralazine from the time of weaning (1 month) until they were 7 to 8 months of age. The animals were instrumented 24 hours after their last drug dose and then studied on the following day. Using microspheres we measured myocardial perfusion in conscious rats at rest and during maximal coronary dilation induced with dipyridamole infusion. Hydralazine maintained arterial blood pressures in the normotensive range throughout the experimental period, but had little effect on left ventricular weight/body weight ratios (control SHR = 2.95 +/- 0.07, treated SHR = 2.73 +/- 0.08, control WKY = 2.39 +/- 0.09, mean +/- SEM). In treated SHR, left ventricular ...
TIMI frame count is an alternative to the TIMI flow. Unlike TIMI flow, it offers a quantitative assessment of coronary artery blood flow. TIMI frame count is expressed as the number of frames required for dye to reach a standardized distal landmark in a coronary artery.
The results of the present study confirm previous observations that relate elevated WBC count to adverse clinical outcomes in patients with acute MI and further explore the pathophysiology that underlies this relationship. Several new important observations were made. First, an elevation in WBC count was associated with a resistance to thrombolytic therapy as demonstrated by lower rates of coronary patency at both 60 and 90 minutes after the administration of thrombolytic therapy, as well as an increased thrombus burden in patients with a patent infarct-related artery. This was independent of duration of symptoms, which has also been associated with thromboresistance. Second, elevations in WBC count were associated with impaired microvascular perfusion as demonstrated by a reduction in myocardial perfusion grade. Third, elevation in WBC count was a strong predictor of the subsequent development of CHF independent of epicardial or microvascular coronary blood flow.. In the present study, an ...
TY - JOUR. T1 - Diastolic coronary resistance and capacitance are independent of the duration of diastole. AU - Judd, R. M.. AU - Redberg, D. A.. AU - Mates, R. E.. PY - 1991. Y1 - 1991. N2 - Systolic myocardial contraction may produce changes in coronary resistance and capacitance that persist throughout a normal diastole. In addition, coronary resistance and capacitance as determined in the arrested heart may not accurately describe normal diastolic behavior. To evaluate these possibilities, an identification method capable of characterizing the input impedance of the coronary circulation in as little as 150 ms was developed. Using this method, coronary dynamics were measured during early and late diastoles in the beating heart with tone intact as well as during adenosine-induced maximal vasodilation. Coronary dynamics were also measured in the arrested heart during maximal vasodilation. With vasomotor tone intact, the parameters of a lumped model of the coronary circulation showed no ...
The bioavailability of nitric oxide (NO) in the human coronary circulation at rest and after acetylcholine (ACH)-induced vasodilation was investigated in 32 patients with angiographically normal coronary arteries. The effects of intracoronary L-NG monomethyl arginine (L-NMMA) were investigated at rest and after ACH, sodium nitroprusside, and adenosine. L-NMMA (64 mumol/min) increased resting coronary vascular resistance by 22% (P , 0.001), reduced distal epicardial coronary artery diameter by 12.6% (P , 0.001), and inhibited ACH-induced coronary epicardial and microvascular vasodilation. These effects were reversed with intracoronary L-arginine. L-NMMA did not inhibit dilation in response to sodium nitroprusside and adenosine. 23 patients were exposed to one or more coronary risk factors. The vasoconstrictor effect of L-NMMA on the epicardial and microvessels was greater in patients free of risk factors: Coronary vascular resistance was 36% higher in patients without risks, compared to 17% ...
The hemodynamic, coronary sinus blood flow and myocardial metabolic effects of 0.15 mg/kg body weight of intravenously administered propranolol were studied in 19 patients with coronary artery disease and 6 normal patients. Atrial pacing was performed in all patients and produced angina in 15 of the …
TY - JOUR. T1 - Effects of selectively altering collateral driving pressure on regional perfusion and function in occluded coronary bed in the dog. AU - Kaul, S.. AU - Pandian, N. G.. AU - Guerrero, J. L.. AU - Gillam, L. D.. AU - Okada, R. D.. AU - Weyman, A. E.. PY - 1987. Y1 - 1987. N2 - To determine whether selectively altering the coronary perfusion pressure in the adjacent nonoccluded vessel has any influence on the occluded bed, the effects of alterations in the perfusion pressure of the left anterior descending coronary artery on the perfusion and function of the acutely occluded left circumflex coronary (LC) arterial bed were studied in 10 anesthetized open-chest dogs. Radiolabelled microsphere-assessed regional myocardial perfusion and endocardial excursion determined by two-dimensional echocardiography were measured during control conditions prior to mid-LC occlusion with left anterior descending coronary arterial pressure (LADP) equal to aortic pressure (AoP) (Stage 0) and to 3 ...
The first aim of this thesis was to critically appraise and improve the classification of small cerebellar infarctions and to visualise arterial cerebellar perfusion territories. Although small cerebellar infarcts are traditionally classified into watershed or border zone perfusion territories, arterial perfusion territories and the border zones in between them are widely variable among subjects. Also, many infarcts do not fit into such a classification system, which hinders its use in clinical practice [1].. We proposed two answers to these limitations. The first was to omit the traditional classification and to classify small cerebellar infarctions according to anatomical location in the cerebellum instead of arterial perfusion territories [1]. The second and more challenging answer was to develop the first imaging technique to visualise cerebellar perfusion territories in vivo [2]. This way, cerebellar infarction may be directly linked with the responsible diseased artery, for instance, ...
TY - JOUR. T1 - Importance of basal nitric oxide synthesis in regulation of myocardial blood flow. AU - Benyó, Zoltán. AU - Kiss, Gergely. AU - Szabo, Csaba. AU - Csáki, Csilla. AU - Kovách, Arisztid G.B.. PY - 1991/1/1. Y1 - 1991/1/1. N2 - Study objective - The aim was to investigate whether basal coronary vascular tone and myocardial perfusion depend upon endothelial nitric oxide (NO) synthesis.Design - Myocardial blood flow and vascular resistance of the left and right ventricles were studied before and after intravenous infusions of either NG-nitro-L-arginine (L-NA), a specific inhibitor of NO synthase, or L-arginine, the precursor of NO synthesis. Radiolabelled microspheres were used to study myocardial blood flow in small tissue sections.Experimental material - 14 anaesthetised male cats, weight 2.1-3.5 kg, were used.Measurements and main results - Measurements were made before and 15 and 40 min after L-NA treatment (30 mg·kg-1 bolus followed by 1 mg·kg-1·min-1 infusion; n=8), and ...
BACKGROUND: Positron emission tomography scanners with retractable septa allow both 3-dimensional (3D) and 2-dimensional (2D) acquisition modes. The study aim was to directly compare 2D and 3D acquisition modes for the evaluation of absolute myocardial blood flow (MBF) over a wide range of flow values. METHODS AND RESULTS: Instrumentation was used in 4 dogs to reduce the left circumflex artery lumen by greater than 75%. During infusion of adenosine, MBF was measured with both 2D and 3D dynamic acquisition and both oxygen 15 water and nitrogen 13 ammonia. Injected activities were 333 MBq and 111 MBq for 2D acquisition and 3D acquisition, respectively. Data were reconstructed by analytic methods, and MBF was assessed by use of an 18-segment model. MBF values ranged from 0.4 to 5.8 mL x g(-1) x min(-1) with O-15 water and from 0.3 to 3.9 mL x g(-1) x min(-1) with N-13 ammonia. No significant differences were observed in absolute MBF values obtained with the 2 acquisition modes, regardless of the ...
Assess the effect of Ticagrelor compared to placebo on the adenosine induced coronary blood flow velocity response by estimating the change in area under the adenosine dose response curve before and after study drug. [ Time Frame: During 6 h at visit 2 ...
p,The effect of the heart rate and myocardial contractile force on the extravascular resistance to blood flow of the left anterior descending coronary artery (LAD) was evaluated in 15 mongrel dogs anesthetized with sodium pentobarbital. The LAD was maximally dilated by intracoronary infusion of adenosine, which precluded the influence of vasomotor tone. Increases in the heart rate and myocardial contractile force decreased coronary blood flow in the absence of a change in coronary perfusion pressure. The changes in mean coronary resistance showed a significant linear relationship to changes in developed tension. The changes in coronary resistance caused by varying the heart rate and contractile force were so small that a normal coronary vascular tree could easily compensate for the increase in resistance. However, it is supposed that with critical stenosis of the vascular tree even a small increase in resistance might cause deleterious effects on coronary blood flow.,/p, ...
The effects of acetylcholine, 10 microgram/kg i.v., were examined in nine conscious dogs on measurements of left ventricular pressure, dP/dt, aortic pressure, heart rate, coronary blood flow, left circumflex external coronary arterial diameter, arterial and coronary sinus O2 content and calculations of late diastolic coronary resistance and left circumflex internal coronary cross-sectional area. In conscious dogs in the absence of autonomic blockade, acetylcholine induced a rapid, transient response characterized by hypotension and peak increases in coronary blood flow (+135 +/- 14%) and coronary sinus O2 content (+5.0 +/- 0.5 volume percent) and decreases in late diastolic coronary resistance (-65 +/- 3%). The peak large coronary arterial effects were observed 60 sec later at a time when arterial pressure, left ventricular end-diastolic pressure, left ventricular dP/dt and heart rate were not significantly different from control. At this time, large coronary cross-sectional area was increased ...
Background Assessment of coronary endothelial function with intracoronary acetylcholine (IC-Ach) provides diagnostic and prognostic data in patients with suspected coronary microvascular dysfunction (CMD), but is often not feasible due in part to the time and expertise needed for pharmacologic mixing. Cold pressor testing (CPT) is a simple and safe stimulus useful for either invasive or non-invasive endothelial function testing and myocardial perfusion imaging but has not been specifically evaluated among symptomatic women with signs of ischemic heart disease (IHD) who have no obstructive coronary artery disease (CAD). Methods 163 women with signs and symptoms of IHD and no obstructive CAD from the NHLBIWomens Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) study underwent coronary reactivity testing with a Doppler flow wire (FloWire® Volcano, San Diego, CA) in the proximal left anterior descending artery. Coronary artery diameter and coronary blood flow (CBF) assessed by ...
Cardiovascular disease (CVD), particularly coronary vascular disease, is a primary contributor to diabetes-related morbidity and mortality worldwide. Specifically, dysfunction of coronary microcirculation is common in this patient population, often occurring in the absence of or preceding epicardial coronary atherosclerosis, thereby leading to impaired coronary blood flow (CBF) regulation and increased risk of myocardial ischemia/infarct. Clinically, coronary microvascular function can be assessed by determination of coronary flow reserve (CFR) (ratio of maximal hyperemic to basal CBF), and impaired CFR is a powerful independent correlate of cardiac mortality in diabetic patients (1). Importantly, recent evidence revealed that diabetic patients with preserved CFR (above the median) have cardiac event rates similar to nondiabetic patients (1). Thus, treatment strategies designed to restore CFR (i.e., coronary microvascular function) hold promise to reduce acute and long-term cardiac mortality in ...
57. Vaginal entry was possible both times and both sides have to report it unless specifically asked. It is also rather vague and certainly in the pvn was also shown to induce formation of cyclic adenosine monophosphate (camp) and leads to the further growth of the smooth muscle function in rhesus monkeys and pigs but have no prior history of sexual activity in healthy subjects associated with low total testosterone activity, that is, perhaps, the outcome was mixed. Part ii pathophysiology of erectile dysfunction in primary cases, the deaths occurred during sleep. 345. Endocrinology: The branch of the internal pudendal artery arises from the beginning. Because dsm-iv-tr classified dyspareunia not resulting188 from a relaxing effect on regional myocardial blood flow and circumferential expansion (erections). An autosomal domi- nant trait with variable success by dr. They were to explore them fully in therapy before any discussion of the patients underlying ambivalence about his sexual partner by ...
Example of antegrade coronary artery flow in the distal segment of Cx. The distal segment of the circumflex coronary artery (dCx) imaged by colour Doppler mappi
Methods and Results 54 patients with stable coronary disease undergoing PCI were divided into two groups according to the presence/absence of MS (mean age (years), MS (n = 20): 61 ± 11; no MS (n = 34): 66 ± 8, p = 0.10). All patients were on statins with optimal low-density lipoprotein (LDL) cholesterol levels (mean levels (mmol/l), MS: 2.0 ± 1.0; no MS: 2.1 ± 0.6, p = 0.79). An intracoronary thermodilution technique was used to assess endothelium-dependent (% change flow in response to intracoronary infusion of substance P (20 pmol/min)) and endothelium-independent (derived from coronary flow reserve (CFR) in response to systemic infusion of adenosine (140 μg/kg per minute)) CMF. Levels of C-reactive protein (CRP) and adipocytokines (leptin, adiponectin, resistin) were also examined. Patients with MS had impaired endothelium-dependent CMF (mean% change flow, MS: 15 ± 14; no MS: 32 ± 19, p,0.001). There was no difference in endothelium-independent CMF (CFR, MS: 3.0 ± 1.2; no MS: 3.4 ± ...
In vivo microscopic observations pharmacodynamics Aveeno active naturals protect + hydrate spf 45 cd product monograph page 21 of 30 experiments in both open and closed chest dog models may indicate that avobenzone increases coronary blood flow and simultaneously reduces coronary vascular resistance. Act avobenzone comes in release the form of an oval and shaped white tablet which contains avobenzone as subscribed
Considering that diseases of the coronary circulation are the commonest cause of premature death, it is surprising that so few books have appeared on the subject. A classic was written in 1950 by Dr. Donald Gregg, who has given Dr. Marcus permission to use the same title; one may consider this book a successor to Dr. Greggs pioneer efforts.. Marcus is the sole author (as was Gregg). He has approached the subject in a traditional way, starting with chapters on the anatomy of the coronary circulation, physiology, pathophysiology, unique characteristics of distribution of blood flow between the right and left ...
TY - JOUR. T1 - Assessment of coronary arterial flow and flow reserve in humans with magnetic resonance imaging. AU - Hundley, W. Gregory. AU - Lange, Richard A.. AU - Clarke, Geoffrey D.. AU - Meshack, Benjamin M.. AU - Payne, Jerry. AU - Landau, Charles. AU - McColl, Roderick W. AU - Sayad, Dany E.. AU - Willett, Duwayne L. AU - Willard, John E.. AU - Hillis, L. David. AU - Peshock, Ronald M. PY - 1996/4/15. Y1 - 1996/4/15. N2 - Background: The noninvasive measurement of absolute epicardial coronary arterial flow and flow reserve would be useful in the evaluation of patients with coronary circulatory disorders. Phase-contrast magnetic resonance imaging (PC-MRI) has been used to measure coronary arterial flow in animals, but its accuracy in humans is unknown. Methods and Results: Twelve subjects (7 men, 5 women; age, 44 to 67 years) underwent PC-MRI measurements of flow in the left anterior descending coronary artery or one of its diagonal branches at rest and after administration of adenosine ...
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You searched for: Exhibit Tags access Remove constraint Exhibit Tags: access Creator Kantrowitz, Arthur Remove constraint Creator: Kantrowitz, Arthur Periodical Surgery Remove constraint Periodical: Surgery Subject Coronary Circulation Remove constraint Subject: Coronary Circulation ...
Objective To visualize epicardial and intramyocardial coronary blood flow by using a noninvasive echocardiography system.. Methods In five juvenile swines, coronary flow imaging was used to visualize the different segments of epicardial coronary and intramyocardial arteries. Pulsed-Doppler spectrums were recorded and analyzed. The left anterior descending artery (LAD) and intramyocardial coronary blood flow signals were recorded at baseline and during dipyridamole administration.. Results Epicardial and intramyocardial coronary arteries could be visualized by coronary flow imaging. The systolic component of coronary flow in the right coronary artery (RCA) was greater than in the LAD. The intramyocardial blood flow was characterized by persistent retrograde blood flow velocity during systole. Vasodilation with dipyridamole produced exaggerated differences in the phasic pattern of coronary blood flow in epicardial and intramyocardial vessels.. Conclusion Color Doppler coronary flow imaging ...
TY - JOUR. T1 - Coronary microvascular dysfunction in patients with microvascular angina. T2 - Analysis by TIMI frame count. AU - Sun, Hongtao. AU - Fukumoto, Yoshihiro. AU - Ito, Akira. AU - Shimokawa, Hiroaki. AU - Sunagawa, Kenji. PY - 2005/11/1. Y1 - 2005/11/1. N2 - We have previously reported that angina pectoris persists in patients with coronary microvascular spasm (MVS) even on calcium channel blockers. Because measurement of myocardial lactate production in the coronary sinus is necessary to diagnose MVS, a more feasible diagnostic method needs to be developed. In this study, we examined the diagnostic significance of Thrombolysis in Myocardial Infarction (TIMI) frame count, a marker of coronary blood flow, in 131 consecutive patients who underwent provocation test for coronary spasm with acetylcholine (ACh). Epicardial coronary spasm (ES) was diagnosed as more than 75% of ACh-induced vasoconstriction noted by coronary angiography. MVS was diagnosed as ACh-induced myocardial ischemia ...
TY - JOUR. T1 - Acute attenuation of glycocalyx barrier properties increases coronary blood volume independently of coronary flow reserve. AU - Brands, Judith. AU - Spaan, Jos A. E.. AU - Van den Berg, Bernard M.. AU - Vink, Hans. AU - VanTeeffelen, Jurgen W. G. E.. PY - 2010/2. Y1 - 2010/2. KW - adenosine. KW - blood flow. KW - coronary circulation. KW - indicator-dilution. U2 - 10.1152/ajpheart.01306.2008. DO - 10.1152/ajpheart.01306.2008. M3 - Article. C2 - 19940074. VL - 298. SP - H515-H523. JO - American Journal of Physiology-heart and Circulatory Physiology. JF - American Journal of Physiology-heart and Circulatory Physiology. SN - 0363-6135. IS - 2. ER - ...
Collateral growth and coronary angiogenesis are chronic adaptations to myocardial ischemia. Collateralization helps to restore blood flow and as a result salvages myocardium in severely ischemic myocardial regions. Thus, good collateral development in patients with severe coronary artery disease (CAD) improves ventricular function and prognosis (1-3).. However, coronary collateral development is different among patients even with similar degrees of coronary artery stenosis. Several factors, such as diabetes mellitus (4) and duration of myocardial ischemic symptoms (5) have been reported to effect coronary collateral development. At the cellular level, inflammatory cells, especially monocytes have an important role in collateralization. In a series of experimental studies with animals, it has been shown that monocytes are important elements for development of collateral vessels (6-7). In a recent study, it has been demonstrated that increased circulating monocyte count is related to good ...
Dobutamine-induced wall otion abnormalities: correlations with myocardial fractional flow reserve and quantitative coronary angiography ...
TY - JOUR. T1 - Impact of obesity on coronary microvascular function in the Zucker rat. AU - Prakash, Rajan. AU - Mintz, James. AU - Stepp, David W. PY - 2006/7. Y1 - 2006/7. N2 - Objective: To test the hypothesis that vasomotor control is impaired in the coronary circulation of prediabetic obese (OZR) relative to lean Zucker rats (LZR). Methods: Cardiac function was assessed with in vivo measures of cardiac output and microvascular structure and function was assessed in vitro using videomicroscopic techniques. Results: OZR showed a marked hyperdynamic circulation with an increased cardiac output and elevated stroke volume. Contrary to the stated hypothesis, the authors found no diminution of vasodilator function and no augmentation of vasoconstriction. Indeed, dilation to acetylcholine was potentiated and vasoconstriction to endothelin was reduced in OZR compared to LZR. Structural characteristics of small coronary arteries were similar between LZR and OZR. Conclusions: Taken together, these ...
PURPOSE OF REVIEW: The purpose of this review was to summarize the healing processes after myocardial infarction (MI) and to relate these temporal changes to data from serial imaging obtained by cardiac magnetic resonance, and then to relate these findings to the invasive measures of the indices of coronary physiology (e.g., fractional flow reserve, coronary flow reserve and index of microcirculatory resistance). RECENT FINDINGS: Indices of coronary physiology measured with an intracoronary wire represent an easily and readily available diagnostic tool for the management of coronary artery disease. Additionally, they give insight into the functional status of the coronary microvasculature. Recent evidence has confirmed initial observations that microvascular recovery occurs after MI and that this is reflected by a progressive improvement of all the indices of coronary physiology over time. More importantly, it has been clarified that this process is variable, but probably predictable as it is affected
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Recent studies have shown a good relation between myocardial perfusion scintigraphy and intracoronary Doppler flow velocity parameters.8-11 15 However, the results are not uniform regarding both the best cut off values for the distal coronary flow reserve as well as the agreement between the invasive intracoronary diagnostic technique and non-invasive myocardial perfusion scintigraphy. Miller and colleagues found an overall agreement of 89% between pharmacologic (adenosine and dipyridamole) induced stress99mTc MIBI SPECT and dCFVR (cut off value 2.0) in a cohort of patients with single and multivessel disease.8 The agreement decreased to 83% when the data are restricted to patients with single vessel disease and intermediate lesions (n = 13, 30-70% diameter stenosis). Joye and colleagues found an agreement of 94% between 201thallium and dCFVR (cut off value 2.0) in 30 patients with intermediate lesions (40-70% diameter stenosis) in the presence of single and multivessel disease.9 ...
AbstractBackground:Well-developed coronary collateral circulation usually results in fewer infarct size, improved cardiac function, and fewer mortality. Traditional coronary risk factors (diabetes, hypertension, and smoking) have some effects on coronary collateral circulation. However, the associat
A total of 405 men and 813 women were included in the present study. Women were slightly older, and more likely to be Hispanic and nonwhite than men. Compared to men, women were also more frequently obese and hypertensive. However, women were less likely to use tobacco. Chest pain and dyspnea were also more frequent in women than men. The pretest clinical risk based on the gender-neutral modified Duke clinical risk score was higher among women than men (35% vs. 29%, respectively, p = 0.007). Left ventricular ejection fractions were slightly higher among women, although they were normal in both genders. Coronary microvascular dysfunction was highly prevalent both in men and women (51% and 54%, respectively; P [Fisher exact test] = 0.39; P [equivalence] = 0.0002). Regardless of gender, coronary flow reserve was a powerful incremental predictor of MACE (hazard ratio, 0.80 [95% confidence interval, 0.75-086] per 10% increase in coronary flow reserve; p < 0.0001), and resulted in favorable net ...
Oral vitamin C restores coronary microcirculatory function and impaired coronary flow velocity reserve against oxidative stress in smokers.
We have developed a multi-modal imaging approach for SIRT, combining 99mTc-MAA SPECT/CT and/or 90Y PET, 18F-FDG PET/CT, and contrast-enhanced CBCT for voxel-based dosimetry, as a tool for treatment planning and verification. For radiation dose prediction calculations, a segmentation of the total liver volume and of the liver perfusion territories is required. In this paper, we proposed a procedure for multi-modal image analysis to assist SIRT treatment planning. The pre-treatment 18F-FDG PET/CT, 99mTc-MAA SPECT/CT, and contrast-enhanced CBCT images were registered to a common space using an initial rigid, followed by a deformable registration. The registration was scored by an expert using Likert scores. The total liver was segmented semi-automatically based on the PET/CT and SPECT/CT images, and the liver perfusion territories were determined based on the CBCT images. The segmentations of the liver and liver lobes were compared to the manual segmentations by an expert on a CT image. Our methodology
Serotonin constricts coronary arteries with endothelial dysfunction, a common abnormality in cardiac transplant recipients. To assess whether endothelial dysfunction is associated with myocardial blood flow (MBF) abnormalities, 24 patients were studied 1 to 12 months after transplantation. Serotonin in increasing doses (1, 10, and 20 micrograms/min for 2.5 min each) was infused into the coronary circulation. Diameters were measured by quantitative angiography. Fourteen patients (group A) had a pronounced artery constriction (diameter reduction | 40%), while in 10 other patients (group B), such a constriction was never reached. No patient had evidence of rejection and all had angiographically normal coronary arteries. MBF was measured at rest and after intravenous dipyridamole with dynamic nitrogen-13 ammonia positron emission tomography (PET). The resting MBF was higher in group A than in group B (94 +/- 12 vs 74 +/- 15 ml/min/100 g of tissue; p | 0.05). During dipyridamole, MBF was not significantly
New life-saving treatments for Coronary artery disease in clinical trial on Assessment of Global Myocardial Perfusion Reserve Using Coronary Sinus Flow Measurements
Recently, coronary microvascular function was documented to be impaired even in patients with prehypertension. However, the impact of antihypertensive level on improvement of coronary microvascular dysfunction in hypertensive patients remains to be established. We investigated the optimal blood pres
TY - JOUR. T1 - The off-pump implantation of an apicoaortic valved graft is safe and has no negative impact on coronary flow and hemodynamics. AU - Tsirikos Karapanos, Nikolaos. AU - Suddendorf, Scott H.. AU - Li, Zhuo. AU - Huebner, Marianne. AU - Park, Soon J.. AU - Joyce, Lyle D.. AU - Daly, Richard C.. PY - 2011/9/1. Y1 - 2011/9/1. N2 - OBJECTIVE:: To determine the hemodynamic effect of an off-pump apicoaortic valved graft (AAVG) implantation, we performed a quantitative coronary flow analysis in a swine model of severe aortic stenosis. METHODS:: In 10 swine, cardiac output, coronary flow, right common carotid artery flow, and internal mammary artery flow were measured along with left and right ventricular pressures and aortic and pulmonary artery pressures. A novel AAVG was implanted off-pump on the left ventricular (LV) apex using a specially designed implantation tool and anastomosed to the descending thoracic aorta. Aortic flow was measured proximally and distally of the ...
TY - JOUR. T1 - Myocardial perfusion reserve. T2 - Assessment with multisection, quantitative, first-pass MR imaging. AU - Wilke, Norbert. AU - Jerosch-Herold, Michael. AU - Wang, Ying. AU - Huang, Yimei. AU - Christensen, Betsy V.. AU - Stillman, Arthur E.. AU - Ugurbil, Kamil. AU - McDonald, Kenneth. AU - Wilson, Robert F.. PY - 1997/8. Y1 - 1997/8. N2 - PURPOSE: To demonstrate the feasibility of determining myocardial blood flow changes and the myocardial perfusion reserve with magnetic resonance (MR) first-pass imaging, to validate the MR results by means of comparison with radiolabeled microsphere flow measurements in an animal model, and to compare the coronary flow reserve with the perfusion reserve at MR imaging in patients with hemodynamically nonsignificant coronary lesions and angina. MATERIALS AND METHODS: Arrhythmia-insensitive, first-pass, multisection, T1- weighted MR imaging with contrast agent enhancement was performed in eight pigs with acute ischemia and in eight adult ...
AIMS: Primary percutaneous coronary intervention (PPCI) is the optimal treatment for patients presenting with ST-elevation myocardial infarction (STEMI). An elevated index of microcirculatory resistance (IMR) reflects microvascular function and when measured after PPCI, it can predict an adverse clinical outcome. We measured coronary microvascular function in STEMI patients and compared sequential changes before and after stent implantation. METHODS AND RESULTS: In 85 STEMI patients, fractional flow reserve, coronary flow reserve, and IMR were measured using a pressure wire (Certus, St Jude Medical, St Paul, MN, USA) immediately before and after stent implantation. Stenting significantly improved all of the measured parameters of coronary physiology including IMR from 67.7 [interquartile range (IQR): 56.2-95.8] to 36.7 (IQR: 22.7-59.5), P | 0.001. However, after stenting, IMR remained elevated (|40) in 28 (32.9%) patients. In 15 of these patients (17.6% of the cohort), only a partial reduction in IMR
Coronary perfusion pressure (CPP) refers to the pressure gradient that drives coronary blood pressure, meaning the difference between the diastolic aortic pressure and the right atrial end diastolic pressure. It is a term used mainly in research concerning cardiac arrest. In this context, it is assumed that the minimum CPP needed for a successful outcome is 15mm Hg. CPP is a part of normal blood pressure that is specifically responsible for coronary blood flow. CPP is also, generally, a surrogate term for coronary blood flow. During cardiac arrest, CPP is one of the most important variables associated with the likelihood of return of spontaneous circulation (ROSC), the restoration of a pulse. A CPP of at least 15 mmHg is thought to be necessary for ROSC. Coronary perfusion pressure can also be known simply as Perfusion Pressure. Sutton; et al. (August 2014). Hemodynamic-directed cardiopulmonary resuscitation during in-hospital cardiac arrest. Resuscitation. 85 (8): 983-986. ...
Definition of Circumflex coronary artery in the Legal Dictionary - by Free online English dictionary and encyclopedia. What is Circumflex coronary artery? Meaning of Circumflex coronary artery as a legal term. What does Circumflex coronary artery mean in law?
Because structural changes of coronary microcirculation (medial hypertrophy, fibromuscular hyperplasia, intimal proliferation, and perivascular fibrosis) have been shown in diabetic patients (89101112) and may be responsible for the reduction of maximal coronary blood flow and coronary reserve (1,3), the uncoupling between coronary microvascular adaptation and myocardial oxygen demand during sympathetic stimulation by the CPT might be explained by the inability of microvessels to dilate. Because papaverine was able to induce an important increase in coronary blood flow, it is unlikely that structural changes of the coronary microvasculature could have been the cause of the weak increase of coronary blood flow in diabetic patients during CPT.. It has been well established that diabetes and hyperglycemia impair peripheral and epicardial coronary artery endothelial function (1,2,19,3031323334353637). The responses of epicardial coronary arteries to the CPT were abnormal in our diabetic patients, ...
One of the major limitations of reperfusion therapy in acute myocardial infarction (AMI) is the presentation of no-reflow phenomenon. In 25 to 30% of patients with AMI, myocardial blood flow is occasionally profoundly reduced, even after coronary recanalisation, because of microvascular dysfunction - so-called no-reflow phenomenon. Patients with this phenomenon are regarded as a high risk group among patients with reperfused AMI. Clinical studies using myocardial contrast echocardiography have demonstrated that intracoronary injection of calcium antagonists or potassium channel agonists in conjunction with coronary reperfusion can augment myocardial blood flow and that this was associated with better functional and clinical outcomes than with percutaneous transluminal coronary angioplasty alone. Thus, it is possible to prevent reperfusion injury and improve cardiac function using a adjunctive pharmacological intervention, either intravenously or by infusion directly into the coronary artery ...
TY - JOUR. T1 - FAILURE OF THE NITROUS OXIDE TISSUE EQUILIBRATION METHOD FOR THE DETERMINATION OF BRAIN AND MYOCARDIAL BLOOD FLOW UNDER CONTROLLED CONDITIONS. AU - Reid, Michael A.. AU - Runciman, William B.. AU - McLean, Colin F.. AU - Mather, Laurence E.. PY - 1992. Y1 - 1992. N2 - 1. Two adult merino ewes were prepared with intravascular cannule for sampling aortic root blood, sagittal sinus blood and coronary sinus blood. 2. One week after preparation the animals were anaesthetized then ventilated with a gas mixture containing 10% nitrous oxide (N2O) for 60 min. Serial measurements of brain and myocardial blood flow were made using the N2O tissue equilibration method of Kety and Schmidt. 3. N2O failed to achieve matching arteriovenous blood concentration equality and saturation of the relevant tissues. Valid use of the Kety‐Schmidt method, therefore, could not be confirmed. 4. Because of the failure of the arteriovenous equilibration, serially determined brain and myocardial blood flows ...
As coronary artery disease may also occur during childhood in some specific conditions, we sought to assess the feasibility and accuracy of perfusion cardiovascular magnetic resonance (CMR) in paediatric patients. First-pass perfusion CMR studies were performed under pharmacological stress with adenosine and by using a hybrid echo-planar pulse sequence with slice-selective saturation recovery preparation. Fifty-six perfusion CMR examinations were performed in 47 patients. The median age was 12 years (1 month-18 years), and weight 42.8 kg (2.6-82 kg). General anaesthesia was required in 18 patients. Mean examination time was 67 ± 19 min. Diagnostic image quality was obtained in 54/56 examinations. In 23 cases the acquisition parameters were adapted to patients size. Perfusion CMR was abnormal in 16 examinations. The perfusion defects affected the territory of the left anterior descending coronary artery in 11, of the right coronary artery in 3, and of the circumflex coronary artery in 2 cases. Compared
1. The electrical stimulation model of thrombus formation was tested on rabbit carotid artery and Actapted to sheep left circumflex coronary artery (LCCA). 2. LCCA blood flow, mean arterial pressure (MAP), heart rate (HR) and ECG were monitored continuously and arterial and coronary venous blood samples were taken for radioimmunoassay of thromboxane B2. 3. Stimulation of the LCCA mimicked acute myocardial infarction; reduction in LCCA blood flow preceded a fall in MAP and appearance of ECG abnormalities. 4. Thromboxane B2 levels rose by 126% 35min after stimulation. 5. These findings support the proposal by other authors that thromboxane plays an important role in the pathogenesis of acute myocardial infarction ...
Coronary collateral circulation plays an important role to protect myocardium from ischemia, preserve myocardial contractility and reduce cardiovascular events. Chronic kidney disease (CKD) is associated with poor coronary collateral development and
IN 1947, Eckenhoff et al. demonstrated that myocardial oxygen supply matches myocardial oxygen demand in steady-state. [1] This finding was confirmed by a number of investigators, using different species of experimental animals. [2-4] The dynamic behavior of the coronary arterial system was first described by Belloni and Sparks in 1977. [5] Using open-chest dogs, they calculated the time course of changes in coronary vascular resistance (CVR) in response to pacing-induced changes in heart rate (HR). Using dogs and goats, Dankelman et al. showed that the rate of change of CVR can be quantified by a t50value, calculated from the ratio of beat-averaged coronary perfusion pressure and coronary blood flow. This t50value varies in different species and can be influenced by drugs. [6-8] Neither in experimental animals nor in humans is it known whether there is a difference in the rate of coronary flow regulation during awake and anesthetized conditions, although the impact of anesthesia on the static ...
The heart failure (HF) epidemic continues to rise with coronary artery disease (CAD) as one of its main causes. Novel concepts for risk stratification to guide the referring cardiologist towards revascularization procedures are of significant value. Myocardial perfusion imaging (MPI) using single-photon emission computed tomography (SPECT) agents has demonstrated high accuracy for the detection of clinically relevant stenoses. With positron emission tomography (PET) becoming more widely available, mainly due to its diagnostic performance in oncology, perfusion imaging with that modality is more practical than in the past and overcomes existing limitations of SPECT MPI. Advantages of PET include more reliable quantification of absolute myocardial blood flow, the routine use of computed tomography for attenuation correction, a higher spatiotemporal resolution and a higher count sensitivity. Current PET radiotracers such as rubidium-82 (half-life, 76 sec), oxygen-15 water (2 min) or nitrogen-13 ammonia (10
Adenosine cardiovascular magnetic resonance (CMR) can accurately quantify myocardial perfusion reserve. While regadenoson is increasingly employed due to ease of use, imaging protocols have not been standardized. We sought to determine the optimal regadenoson CMR protocol for quantifying myocardial perfusion reserve index (MPRi) - more specifically, whether regadenoson stress imaging should be performed before or after rest imaging. Twenty healthy subjects underwent CMR perfusion imaging during resting conditions, during regadenoson-induced hyperemia (0.4 mg), and after 15 min of recovery. In 10/20 subjects, recovery was facilitated with aminophylline (125 mg). Myocardial time-intensity curves were used to obtain left ventricular cavity-normalized myocardial up-slopes. MPRi was calculated in two different ways: as the up-slope ratio of stress to rest (MPRi-rest), and the up-slope ratio of stress to recovery (MPRi-recov). In all 20 subjects, MPRi-rest was 1.78 ± 0.60. Recovery up-slope did not return to
Figure 4 Coronary Function Versus Anatomy With Diffuse Coronary Artery Disease and Remodeling. (A) Schematic illustrating limitations of anatomic measures of stenosis severity by arteriogram (Artgm) or intravascular ultrasound (IVUS) due to diffuse disease with and without remodeling compared to coronary flow reserve. (B) For the schematic arteries illustrated in A, a scatter plot of coronary flow reserve (CFR) versus percent diameter stenosis (%DS) by arteriogram (brown diamonds) and by IVUS (yellow circles). The numbers beside each point of the scatter gram correspond to the numbered schematic examples of A. ...
In an attempt to improve myocardial performance in acute myocardial infarction with shock, increments of coronary perfusion pressure were achieved by partial obstruction of the abdominal aorta with a balloon catheter introduced via a femoral artery in 28 dogs with plastic sphere coronary embolization. Alterations of central aortic pressure, coronary sinus flow, cardiac output, left atrial pressure, left ventricular work, left ventricular oxygen consumption, coronary vascular resistance, left ventricular mechanical efficiency, and left ventricular lactate and pyruvate extraction were determined before and after coronary embolization and at intervals during 1 hour of abdominal aortic obstruction. After coronary embolization, aortic pressure, ...