Background: Coronary slow flow (CSF) phenomenon is characterized by delayed opacification of coronary vessels in a normal coronary angiogram. Although clinical and pathological features have been previously described, the underlying pathophysiology has not been fully elucidated. In this study, we aimed to evaluate central aortic pressure, aortic stiffness and left ...

BACKGROUND: Identification of high risk sub-groups for early initiation of preventive medical therapy requires widespread population screening using simple, inexpensive tests. High pulse pressure has been shown to predict adverse coronary events. We examined if this correlation was related to a greater coronary plaque burden in patients with high pulse ...

INTRODUCTION: BAY-79 is an inhibitor of receptor tyrosine kinases with high selectivity versus other kinases. Species scaling, complicated by nonlinear pharmacokinetics, predicted a C(max.u) of 36-178nmol/L at the human efficacious exposure. METHODS: Preclinical cardiovascular safety pharmacology studies assessed currents (hERG, I(Na)), action potential (AP, rabbit Purkinje fiber), hemodynamic/ECG parameters (anesthetized ...

In anomalous right coronary artery (RCA), extravascular coronary compression results in dynamic obstruction which can cause effort angina as well as syncope. Measurement of dynamic intracoronary pressure gradient (DeltaP) change across the lesion using dobutamine challenge with rapid atrial pacing (RAP) can be used for assessment of dynamic obstruction in ...

OBJECTIVES: The aim was to investigate the effects of volume and pressure overload and increased coronary perfusion pressure on coronary flow (CF) in congenital heart disease (CHD) patients. BACKGROUND: The effects of CHD on CF are poorly mapped. METHODS: A total of 65 patients with acyanotic CHD and 49 age-matched ...

Coronary flow is different from the flow in other parts of the arterial system because it is influenced by the contraction and relaxation of the heart. To model coronary flow realistically, the compressive force of the heart acting on the coronary vessels needs to be included. In this study, we ...

Undilatable coronary lesions, due to coronary calcification, are encountered with increasing frequency. Percutaneous intervention of such lesions comes with the risk of stent underexpansion, which increases the risk of stent thrombosis and restenosis. A variety of techniques and devices are available to assist the interventionist in the treatment of calcified ...

OBJECTIVE: To investigate the relationship between resting distal coronary pressure to aortic pressure ratio (Pd/Pa) and fractional flow reserve (FFR) obtained during maximal hyperemia. BACKGROUND: FFR is an invasive index of the functional severity of a coronary artery stenosis determined from coronary pressure measurements. It is generally believed that there ...

Coronary pressure measurement has emerged as one of the most promising tool to assist interventional cardiologist to make accurate clinical decisions. Fractional flow reserve (FFR) is a simple way of reliably assessing the functional consequences of coronary atherosclerosis. The training in FFR is easy and coronary pressure measurements can be ...

Patients with pulseless electrical activity or refractory ventricular fibrillation have a very bad prognosis. Coronary angiography and angioplasty may be required to restore an effective circulation, but this must be performed whilst chest compressions are continued. The LUCAS chest compression device is suitable for this purpose. So far there are ...

The mechanisms by which the contracting myocardium exerts extravascular forces (intramyocardial pressure, IMP) on coronary blood vessels and by which it affects the coronary flow remain incompletely understood. Several myocardium-vessel interaction (MVI) mechanisms have been proposed, but none can account for all the major flow features. In the present study, ...

Both hypertension and coronary artery spasm (CAS) are associated with endothelial dysfunction. Thus, a higher incidence of CAS is expected in hypertensive patients. We evaluated the impact of hypertension on CAS with intracoronary acetylcholine (ACh) provocation test. A total of 986 patients (685 hypertensive patients vs 301 normotensive patients) who ...

Pulse pressure (PP) is an independent predictor of myocardial infarction, mainly above 50 years of age. In subjects with preserved ejection fraction (EF), aortic PP predicts the severity of coronary atherosclerosis. Comparable findings in subjects with reduced EF have not been evaluated. In 1337 subjects with severe coronary ischaemic disease, ...

The topic of the J-curve relationship between blood pressure and coronary artery disease (CAD) has been the subject of much controversy for the past decades. An inverse relationship between diastolic pressure and adverse cardiac ischemic events (i.e., the lower the diastolic pressure the greater the risk of coronary heart disease ...

BACKGROUND: Intracoronary physiology techniques have been validated extensively for the assessment of epicardial stenoses but not for the lone study of coronary microcirculation. We performed a comparison between 4 intracoronary physiological indices with the actual structural microcirculatory changes documented in transplanted hearts. METHODS AND RESULTS: In 17 cardiac allograft patients ...

BACKGROUND: Simultaneously measured pressure and flow distal to coronary stenoses can be combined, in conjunction with anatomical measurements, to assess the status of both the epicardial and microvascular circulations. METHODS AND RESULTS: Assessments of coronary hemodynamics were performed using fundamental fluid dynamics principles. We hypothesized that the pressure-drop coefficient (CDPe; ...

The formation and the patterning of the coronary vasculature are critical to the development and pathology of the heart. Alterations in cytokine signaling and biomechanical load can alter the vascular distribution of the vessels within the heart. Changes in the physical patterning of the vasculature can have significant impacts on ...

Citrus paradisi (grapefruit) consumption is considered as beneficial and it is popularly used for the treatment of a vast array of diseases, including hypertension. In the present study, the coronary vasodilator and hypotensive effects of Citrus paradisi peel extract were assessed in the Langendorff isolated and perfused heart model and ...

AIMS: Coronary angiography is widely used to estimate coronary blood flow velocity, as in the TIMI frame count method. However, it is unknown to what extent the injection of dye elevates intracoronary pressure which may accelerate coronary blood flow velocity. In the present study, intracoronary pressure was measured during coronary ...

Animal reports suggest that reflex activation of cardiac sympathetic nerves can evoke coronary vasoconstriction. Conversely, physiological stress may induce coronary vasodilation to meet an increased metabolic demand. Whether the sympathetic nervous system can modulate coronary vasomotor tone in response to stress in humans is unclear. Coronary blood velocity (CBV), an ...

Increased reactive oxygen species (ROS) produced by the failing heart can react with nitric oxide (NO), thereby decreasing NO bioavailability. This study tested the hypothesis that increased ROS generation contributes to coronary endothelial dysfunction in the failing heart. Congestive heart failure (CHF) was produced in six dogs by ventricular pacing ...

BACKGROUND: Intracoronary thermography has been proposed to detect vulnerable plaques. We hypothesized that changes in coronary pressure and flow in the coronary tree may interfere with the temperature measurements obtained with thermistors. METHODS AND RESULTS: First, a very close correlation was found in vitro between the temperature measured by a ...

PURPOSE: To determine the relationship between carotid intima-media thickness (IMT), coronary artery calcification (CAC), and myocardial blood flow (MBF) at rest and during vasomotor stress in type 2 diabetes mellitus (DM). METHODS: In 68 individuals, carotid IMT was measured using high-resolution vascular ultrasound, while the presence of CAC was determined ...

The Langendorff mouse heart model is widely employed in studies of myocardial function and responses to injury (e.g. ischaemia). Nonetheless, marked variability exists in its preparation and functional properties. We examined the impact of early growth (8, 16, 20 and 24 weeks), sex, perfusion fluid [Ca(2+)] and pacing rate on ...

Abdominal perfusion pressure (APP) is defined as the difference between the mean arterial pressure and the intra-abdominal pressure (IAP). IAP elevation results in various side effects, including a decrease in coronary arterial perfusion pressure (CoPP). The present study analyzed the relationship between APP and CoPP in patients undergoing extracorporeal circulation ...

Conscious coronary sinus-cannulated dogs were used to assess the hemodynamic effects and local cardiac norepinephrine (NE) and histamine (HA) release of 4 mechanistically diverse agents either clinically approved or representing a potential novel mechanism for the promotion of wakefulness or attention. Dosing regimens were based on reported or concurrently determined ...

AIMS: We addressed calcium responsiveness in microembolized myocardium at 6 h after coronary microembolization (ME). METHODS AND RESULTS: In anesthetized pigs calcium responsiveness was determined as the increase of a myocardial work index (WI; LV pressure development vs. wall thickening) in response to a graded intracoronary infusion of CaCl(2) at ...

BACKGROUND: Functional/physiological evaluation of coronary artery stenoses may be more important than anatomical measurements of severity. Optimization of thresholds for stenosis intervention and treatment endpoints depend on coupling functional hemodynamic and anatomical data. We sought to develop a single prognostic parameter correlating stenosis-specific anatomy, pressure gradient, and velocities that could ...

The effect of alpha1-receptor blockade with urapidil on coronary blood flow and left ventricular function has been attributed to relief of diffuse coronary vasoconstriction following percutaneous coronary intervention (PCI). We hypothesized that an increase in diastolic time fraction (DTF) contributes to the beneficial action of urapidil. In eleven patients with ...

PURPOSE: It has been reported that mental stress is an independent risk factor for cardiovascular events and impairs coronary circulation. Lavender aromatherapy, one of the most popular complementary treatments, is recognized as a beneficial mental relaxation therapy. However, no study has examined the effect of this therapy on coronary circulation. ...

Chronic hypertension and diabetes produce both macrovascular and microvascular pathophysiological changes. Greater arterial stiffness increases central systolic and pulse pressure, which raises left ventricular afterload and reduces coronary perfusion. Resistance arteries remodelling and capillary rarefaction increase peripheral resistance, thereby contributing to hypertension and amplifying the detrimental haemodynamic effects of arterial ...

OBJECTIVES: To investigate the association between elasticity indexes of aorta and severity of coronary artery disease (CAD) in patients with stable CAD. METHODS: Fifty-six patients with CAD (CAD group) and 40 patients without CAD [non CAD (NCAD group)] were included in the study. Ascending aorta (Ao) diameters (mm) and Ao ...

BACKGROUND: High blood pressure in middle age is a well-established risk factor for cardiovascular disease, but the consequences of low-level elevations during young adulthood are unknown. OBJECTIVE: To measure the association between prehypertension exposure before age 35 years and coronary calcium later in life. DESIGN: Prospective cohort study. SETTING: Four ...

Traditional cardiovascular risk factors have been shown to cause microvascular dysfunction. Most studies that have evaluated microcirculation rely on invasive measurement tools. We used dobutamine stress echocardiography, a validated method to measure coronary flow velocity (CFV) and coronary flow reserve (CFR), in a previously unstudied population without known significant coronary ...

The heterogeneity across the left ventricular wall is characterized by higher rates of oxygen consumption, systolic thickening fraction, myocardial perfusion, and lower energetic state in the subendocardial layers (ENDO). During dobutamine stimulation-induced demand ischemia, the transmural distribution of energy demand and metabolic markers of ischemia are not known. In this ...

This study investigated the effects of intracoronary autologous bone marrow-derived mononuclear cell (BMC) transplantation on coronary microcirculation. Fifteen patients with ischemic cardiomyopathy were treated by intracoronary infusion of BMCs via the patent infarct-related artery. The thermodilution-derived coronary flow reserve, index of microvascular resistance, pressure-derived collateral flow index, and coronary wedge ...

Comparative study of pathomorphology of myocardial circulation under conditions of increased afterload of the left or right ventricles showed similar changes. All compartments of the coronary bed were plethoric, capillary blood stasis and perivascular edema, more pronounced in arterial vessels, were detected in both cases. These changes equally involved both ...

The coronary pressure wire is used for physiological assessment of the coronary vasculature increasingly frequently in clinical practice. Fractional flow reserve (FFR) can now be used to assess lesion severity in a variety of anatomical situations. Increasingly, the coronary pressure wire is being used to interrogate the coronary microvasculature. Coronary ...

Xantinole nicotinic acid (NA) dose dependently lowers plasma levels of atherogenic lipoproteins and increases blood flow through vasodilation. The aim of this study was to evaluate the effect of NA on cutaneous microcirculation in patients with coronary artery disease and hyperlipidemia. In this open pilot study, five men and three ...

BACKGROUND: The severity of epicardial coronary stenosis can be assessed by invasive measurements of trans-stenotic pressure drop and flow. A pressure or flow sensor-tipped guidewire inserted across the coronary stenosis causes an overestimation in true trans-stenotic pressure drop and reduction in coronary flow. This may mask the true severity of ...

The speed with which horseflies (Diptera: Tabanidae) obtain a bloodmeal suggests they have potent vasodilators. We used isolated perfused rat heart to examine the vasoactivity of salivary gland extracts (SGEs) of three horsefly species, Hybomitra bimaculata Macquart, Tabanus bromius Linnaeus and Tabanus glaucopis Meigen. Administration of horsefly SGEs to the ...

OBJECTIVE: Although the cardiovascular system is highly sensitive to thyroid hormones, the cardiovascular effects of subtle thyroid dysfunction such as subclinical hypothyroidism (SHT) remain unclear. Therefore, we investigated coronary flow reserve (CFR) reflecting coronary microvascular function in patients with SHT. METHODS: Fifty subjects with SHT and 30 control subjects with ...

Orientation of a bi-leaflet prosthesis (BLP) might influence coronary perfusion. The aim of this study was to investigate the influence of the orientation on coronary perfusion pressure during hyperemia and adrenergic stimulation. During hyperemia perfusion pressure determines coronary blood flow. Fourteen patients with normal coronary angiogram underwent aortic valve replacement ...

BACKGROUND: The benefits of intra-aortic balloon pumping (IABP) usage reportedly occur through systolic unloading of the left ventricle and the augmentation of diastolic coronary flow. The aim of this study was to assess the change in intracoronary pressure distal to the coronary stenosis after the IABP by using an intracoronary ...

OBJECTIVE: To investigate the underlying mechanisms of a decreased coronary flow reserve after myocardial infarction (MI) by analysing the characteristics of the diastolic hyperaemic coronary pressure-flow relationship. DESIGN: Prospective study. SETTING: Tertiary care hospital. PATIENTS: 68 patients with a recent MI and 27 patients with stable angina pectoris (AP; control ...

AIM: The purpose of this study was to evaluate the hypothesis that acute hyperglycaemia in hearts of rats without diabetes alters coronary vascular responses to nitric oxide (NO), adenosine (ADO) and phenylephrine (PHE). METHODS: Coronary function was studied in isolated, Langendorff-perfused, non-beating rat hearts that were perfused with an oxygenated ...

A 72-year-old woman was admitted to our hospital for chest pain and dyspnea. Admission electrocardiogram revealed T-wave inversion in precordial leads. Coronary angiography showed no significant coronary artery disease. Left ventriculography showed apical akinesis and basal hyperkinesis with an intraventricular pressure gradient of 60 mmHg. After 4 days left ventricular ...

K(ATP) channels are involved in regulating coronary function, but the contribution of endothelial K(ATP) channels remains largely uncharacterized. We generated a transgenic mouse model to specifically target endothelial K(ATP) channels by expressing a dominant negative Kir6.1 subunit only in the endothelium. These animals had no obvious overt phenotype and no ...

The purpose of this study was to define binodenoson dosing regimens that produce coronary hyperemia comparable to those of adenosine and that are tolerated well by patients. An open-label, randomized, parallel-group, multicenter study enrolled adult patients who had completed diagnostic cardiac catheterization. Coronary blood flow velocity (CBFV) was measured with ...

Objective evaluation of the functional significance of individual stenosis in patients with multiple lesions is crucial when performing percutaneous coronary intervention (PCI). Here we propose a novel lesion-specific parameter, the epicardial resistance index (ERI), which is derived from intracoronary pressure measurements, and validate its clinical usefulness. The ERI is defined ...