Estrogen replacement therapy reduces risk of cardiovascular events by altering coronary vasoregulation and distribution of blood flow. Vessel reactivity and blood flow distribution were assessed in anesthetized female rabbits in the following groups: 1) sham, 2) ovariectomy, 3) ovariectomy + 17beta-estradiol, and 4) ovariectomy + dehydroepiandrosterone. After a 2-wk treatment, ...

The control of coronary blood flow has been studied for decades, but despite our extensive efforts, the critical regulators of flow are largely unknown. One purpose of this review is to summarize some recent concepts about the control of coronary flow and also point out areas where additional knowledge must ...

This study examined the relationships between paraoxonase genotypes, coronary artery reactivity, and indices of low-density lipoprotein oxidation in healthy men. Impairment in coronary flow reserve, as assessed by positron emission tomography, is associated with lipoprotein oxidation, which is affected by high-density lipoprotein bound enzyme, paraoxonase. Paraoxonase has two common polymorphisms ...

This study compared the TIMI frame count (TFC), which has been proposed as a method for quantifying coronary blood flow, with coronary flow and microvascular function measured with intracoronary Doppler and intracoronary ultrasound. Coronary blood flow volume was calculated from coronary blood velocity (by intracoronary Doppler) and lumen area (by ...

BACKGROUND: Impaired coronary flow reserve (CFR) can be used to indicate vascular dysfunction before the appearance of angiographic lesions. The hepatic lipase (HL) gene has a functional promoter polymorphism at position C-480T, which affects transcription and leads to high activity (C/C) and low activity (C/T, T/T) genotypes. These genotypes modulate ...

BACKGROUND: We hypothesized that coronary blood flow (CBF) reserve could be quantified noninvasively in humans using myocardial contrast echocardiography (MCE). METHODS AND RESULTS: Eleven patients with normal epicardial coronary arteries (group I) and 19 with single-vessel coronary stenosis (group II) underwent quantitative coronary angiography, MCE, and CBF velocity measurements at ...

Coronary flow velocity can be measured by transthoracic Doppler echocardiography (TTDE). The purpose of this study was to detect severe coronary stenosis using the diastolic-to-systolic flow velocity ratio (DSVR) determined by TTDE at rest. We prospectively examined 190 consecutive patients with angina pectoris for whom coronary angiography was planned. Doppler ...

In clinical cardiology, stenosis in a coronary artery is measured on the basis of visual assessment. The reading of coronary arteriograms leads, however, to large inter- and intra-observer variability. Image analysis and computer assistance result in a more consistent assessment, but this approach is mainly based upon static geometric parameters, ...

BACKGROUND: The hypothesis that intravenous L-arginine infusion improves the vasodilatory response to ischemia in the resistance vessels of human lower limbs in relatively young coronary heart disease patients taking vasodilating drugs was tested. METHODS: Twenty patients with onset of symptoms of coronary artery disease before age 50, operated for aortocoronary ...

Diffusely impaired coronary blood flow reserve is difficult to measure non-invasively. We developed and tested a quantitative non-invasive method of measuring coronary blood flow reserve using thallium-201 perfusion imaging. Ten anesthetized dogs were injected simultaneously at rest with thallium-201 and either Ru-103 or Sn-113 microspheres. SPECT images were obtained followed ...

While studying flow-dependent coronary dilation using a Doppler flow velocity guidewire, total occlusion of a stenosed segment of the left circumflex artery during the intracoronary infusion of bradykinin was angiographically documented. Total occlusion was not demonstrated during intracoronary infusion of bradykinin after angioplasty. This is angiographic confirmation of the coronary ...

OBJECTIVE: To quantify the effects of fenoldopam, 0.1 microg/kg/min, on left internal mammary artery (LIMA) and saphenous vein blood flow after coronary anastomosis. DESIGN: Prospective, randomized, double-blind, placebo-controlled trial. SETTING: University teaching hospital, single institution. PARTICIPANTS: Thirty-one American Society of Anesthesiologists III patients undergoing elective coronary revascularization. INTERVENTIONS: A perivascular ...

OBJECTIVE: Aortomyoplasty is a surgical procedure that aims to induce hemodynamic benefits similar to those of the intra-aortic-balloon-pump (IABP). The objective of this study was to compare the coronary blood flow augmentation and afterload reduction produced by IABP and descending aortomyoplasty counterpulsation. METHODS: From a series of fifteen mongrel dogs ...

BACKGROUND: Fractional flow reserve (FFR) and coronary blood flow velocity reserve (CFR) represent physiological quantities used to evaluate coronary lesion severity and to make clinical decisions. A comparison between the outcomes of both diagnostic techniques has not been performed in a large cohort of patients with intermediate coronary lesions. METHODS ...

OBJECTIVES: The study was undertaken to develop a coronary microvascular spasm model in pigs by repeated epicardial coronary artery endothelial injury. BACKGROUND: The pathophysiologic mechanisms responsible for coronary microvascular spasm remain unclear, in large part because a suitable animal model has yet to be found. METHODS: Balloon endothelial denudation was ...

Detection of early vascular changes indicated by lowered coronary flow reserve (CFR) would allow early treatment and prevention of atherosclerosis. The purpose of this study was to test whether it is possible to reproducibly measure CFR with transthoracic Doppler echocardiography (TTE) in healthy volunteers. We measured CFR using dipyridamole infusion ...

BACKGROUND: We hypothesized that ischemia-induced expression of vascular endothelial growth factor (VEGF) and the production of NO stimulate coronary collateral growth. METHODS AND RESULTS: To test this hypothesis, we measured coronary collateral blood flow and VEGF expression in myocardial interstitial fluid in a canine model of repetitive myocardial ischemia under ...

Acute coronary syndromes result in a global impairment of coronary blood flow with nonculprit artery blood flow being associated with culprit artery flow and vice versa. Improvements in nonculprit artery flow are related to improvements in culprit artery flow after percutaneous intervention; nonculprit arteries with abnormal flow sustain greater improvements ...

BACKGROUND: Coronary collaterals are essential to maintain myocardial function in chronic total coronary occlusions (TCOs). The aim of the present study was to assess the collateral circulation in TCOs before coronary angioplasty and to determine the recruitable collateral perfusion after recanalization by use of intracoronary Doppler flow velocimetry. METHODS AND ...

To examine the responses of coronary conduit and resistance arteries to the continuous i.v. administration of nitroglycerin in 15 patients with atypical chest pain, we measured coronary blood flow velocity in the left anterior descending coronary artery using a Doppler guide wire and the lumen diameter and cross-sectional area by ...

The aim of this study was to evaluate determinants of coronary blood flow following primary angioplasty (PA) in acute myocardial infarction (AMI). The corrected TIMI (thrombolysis in myocardial infarction) frame count and the TIMI flow grade were used as indexes of coronary blood flow, and its determinants were examined in ...

Coronary flow estimates were made for a spiral coronary artery segment (identified from a post-mortem replica casting) by using a modified Dean number based on the approximate coil radius of curvature, as suggested earlier. The estimates were found to correlate experimental pressure drop data for helical coiled tubes. Over a ...

BACKGROUND: We previously demonstrated that in vivo electron-beam computed tomography (EBCT)-based indicator-dilution methods provide an estimate of intramyocardial blood volume (BV) and perfusion (F), which relate as BV=aF+b radicalF, where a characterizes the recruitable (exchange) and b the nonrecruitable (conduit) component of the myocardial microcirculation. In the present study, we ...

Restoration of flow-dependent coronary artery dilation by angiotensin-converting enzyme inhibition (ACEI) has been demonstrated in patients with hypertension. The aim of the present study was to evaluate whether dilation of conductance coronary arteries may alter maximal coronary blood flow (CBFmax) and minimal coronary resistance (CRmin) in hypertensive patients with reversible ...

BACKGROUND: The aim of this study was to assess the effect of a 6-month treatment with the inhibitor of the angiotensin-converting enzyme cilazapril on the response of conductance and resistance vessels to endothelium-dependent and independent vasodilators, in a randomized placebo-controlled parallel group single center study. METHODS: Quantitative angiographic and Doppler ...

OBJECTIVE: To determine the effect of nitroglycerin on coronary blood flow velocity during controlled hypotensive anesthesia in humans. DESIGN: Internally controlled prospective study. SETTING: Single university hospital. PARTICIPANTS: Twenty American Society of Anesthesiologists class I and II patients undergoing general anesthesia for surgical resection of a malignancy. INTERVENTIONS: General anesthesia ...

PURPOSE: The purpose of this study was to evaluate the effect of treatment with an angiotensin-converting enzyme (ACE) inhibitor (Cilazapril) for early hypertensive patients in terms of coronary blood flow reserve evaluated by 13NH3-positron emission tomography (PET). METHODS: Before and after 12 weeks of ACE inhibitor treatment, 13NH3-PET with dipyridamole ...

Previous studies have indicated that cardiac events in young patients with hypertrophic cardiomyopathy (HCM) are related to ischaemia rather than to arrhythmia. We measured coronary flow reserve in paediatric HCM and compared the values with those in adult HCM. We studied 12 patients with HCM including six paediatric (<20 years ...

Coronary flow reserve is used to aid understanding why myocardial oxygen consumption may fail to meet demand. Its general aspects are well known, but the problems of using it are not. This manuscript describes three important factors that need to be considered when assessing coronary flow reserve. (1) Maximal flow ...

Flow velocity wave forms of coronary arterial inflow and venous outflow of myocardium are influenced by cardiac contraction and relaxation: arterial flow is exclusively diastolic; venous outflow is systolic. We first discuss the intramyocardial microvascular flow dynamics, then present some results of visualization of transmural microvessels by our needle-probe charge ...

OBJECTIVES: We sought to examine whether distention of the urinary bladder, a physiologic stimulus, could induce impaired coronary circulation in patients with early atherosclerosis. BACKGROUND: Distention of the urinary bladder reflexively causes an increase in sympathetic activity. The effect of such distention on the coronary circulation in patients with early ...

Mammalian hearts exhibit a heterogeneous spatial distribution of blood flows, but flows in near-neighbor regions correlate strongly. Also, tracer (15)O-water washout after injection into the inflow shows a straight log-log relationship between outflow concentration and time. To uncover the role of the arterial network in governing these phenomena, morphometric data ...

OBJECTIVE: Menopause is associated with an increased incidence of cardiovascular disease among women, and estrogen replacement therapy is thought to reduce the risk of coronary artery disease. The mechanism by which this occurs is unclear, but coronary arterial endothelial and vascular smooth muscle cells have been shown to contain estrogen ...

This study investigated the effects of intravascular collagen on coronary collateral blood flow. Collateral vessel growth was stimulated in 11 dogs by embolizing the left anterior descending (LAD) coronary artery with a hollow stainless steel plug. Experiments were performed 41 +/- 7 days after coronary embolization when collateral vessels were ...

The mechanistically novel benzopyran derivative SB-220453, which is undergoing clinical evaluation in migraine, exhibits a high affinity for a selective, but not yet characterized, binding site in the human brain. It inhibits nitric oxide release and cerebral vasodilatation following cortical spreading depression as well as carotid vasodilatation induced by trigeminal ...

BACKGROUND: Measurement of coronary sinus blood flow (CSF) by phase-contrast magnetic resonance (PC-MR) imaging at rest and during hyperemia may allow noninvasive assessment of global coronary hemodynamics. METHODS AND RESULTS: Sixteen healthy volunteers (age, 22 to 32 years) were examined with MR and PET in random order within 1 to ...

BACKGROUND: A residual stenosis and/or microvascular damage have been proposed as mechanisms of TIMI 2 flow for acute myocardial infarction. Coronary flow dynamics were assessed in patients with TIMI 2 flow to predict whether additional intervention would improve TIMI grade. METHODS AND RESULTS: In 35 patients who had a successfully ...

Phasic coronary flow velocity in the left and right coronary artery was recorded in a patient with microvascular angina. Coronary flow velocity during anginal attack was characterized by diminished systolic forward velocity, the appearance of systolic flow reversal, increase in diastolic flow velocity and its rapid deceleration. It was also ...

The cardiovascular effects of AH-1058, a novel calcium channel blocker, were examined in comparison with those of verapamil using canine isolated, blood-perfused papillary muscle, atrioventricular node, and sinoatrial node preparations. Intravenous administration of AH-1058 (20, 50, and 100 microg/kg) or verapamil (20, 50, and 100 microg/kg) to the blood-donor dog ...

OBJECTIVE: Sphingosine 1-phosphate is a naturally occurring biologically active lysophospholipid. Recent studies suggested that sphingosine 1-phosphate is released into the blood flow from activated platelets upon stimulation to exert multiple biological phenomenon. The purpose of this study was to assess the effects of sphingosine 1-phosphate on sinus automaticity, ventricular contraction ...

To evaluate the feasibility and usefulness of transthoracic Doppler echocardiography (TTDE) as a non-invasive method in recording distal anterior descending (LAD) coronary flow velocity, we compared coronary flow reserve (CFR) measured by TTDE with measurements by intracoronary Doppler wire (ICDW). Twenty-one patients without LAD stenosis were studied. ICDW performed at ...

Intravenous injection of growth hormone in anaesthetized pigs has been shown to cause coronary vasoconstriction by antagonizing the vasodilatory effects of 2-adrenergic receptors. Because nitric oxide is believed to modulate or mediate 2-adrenergic effects, the present study was undertaken in the same experimental model to determine the role of nitric ...

The study present thermographic assessment of the effectiveness of temporary stellate blockade performed during cardiosurgical procedures. The assumption behind this method was the increase in the temperature of upper extremity on the side of blockade, due to the broadening of arterial bed. MATERIAL AND METHOD: The study was conducted on ...

The effects of JTV-506 ((-)-(3S,4R)-2,2-bis(methoxymethyl)-4-[(1,6-dihydro-1-methyl-6-oxo-3- pyridazinyl)amino]-3-hydroxychroman-6-carbonitrile hemihydrate, CAS 170148-29-5), a novel coronary vasodilator, on hemodynamics, cardiac function and cardiac oxygen consumption were evaluated in anesthetized dogs. In anesthetized, open-chest dogs, JTV-506 (0.3-10 micrograms/kg i.v.) induced a marked increase in coronary blood flow in a dose dependent manner, while at these ...

AIMS: Evaluation of angiographical and intracoronary Doppler-derived parameters of coronary stenosis severity. METHODS AND RESULTS: A total of 225 patients with one-vessel disease were studied before PTCA and at 6 months follow-up. Exercise electrocardiography was performed to document presence (n = 157) or absence (n = 138) of an ST ...

BACKGROUND: Intracoronary (IC) calcium channel blockers (CCB) such as diltiazem and verapamil are frequently utilized during percutaneous coronary interventions to maximize coronary blood flow. Their use, however, may be limited by systemic side effects such as hypotension and bradyarrhythmias. The vasoselective dihydropyridines, such as nicardipine, may be more effective at ...

BACKGROUND: The objective of this study was to evaluate the influence of biopump used for left ventricular assistance on the coronary and carotid flows in dogs with normal heart. The efficacy of the simultaneous use of an intraaortic balloon pump to compensate the possible deleterious effects of the circulatory assistance ...

m-(Iodobenzyl)trozamicol (MIBT) is a recently discovered vesamicol analogue. It has been shown that radiolabelled [125I]MIBT can be used as a marker of cholinergic innervation in the heart as well as in the brain. The purpose of this study was to analyze the direct effects of MIBT on the atrioventricular and ...

To estimate in patients the accuracy of coronary flow measurements performed by means of 0.014" Doppler wires, the time-averaged maximal blood velocity (APV) was recorded in the 3 branches of 36 angiographically normal coronary artery bifurcations selected in 21 patients undergoing cardiac catheterization for various diseases. Contrast medium injections filmed ...

A 5-y-old Paint horse gelding was evaluated for acute laminitis after exposure to black walnut shavings. The gelding's feet were previously soaked in an ice bath continuously for approximately 24 h. Treatment consisted of anti-inflammatory and vasodilator therapy. Serial radiographs revealed progressive palmar deviation of the third phalanx and subsolar ...