Search Results
Results 201 - 250 of 1551
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MacCarthy Philip - - 2005
OBJECTIVES: We aimed to validate the technique of measuring the coronary flow reserve (CFR) with coronary pressure measurements against an established thermodilution technique. BACKGROUND: The CFR has traditionally required measurement of coronary blood flow velocity with the Doppler wire and, more recently, using a thermodilution technique with the coronary pressure ...
Ozaki Morihiro - - 2005
There is increasing evidence that peripheral pulse pressure measured at the brachial artery is a good predictor of coronary heart disease. However, the relation between pulse pressure and angiographically demonstrated coronary artery stenosis has not been fully elucidated. We designed the present study to investigate the association of the various ...
Fokkema Dirk S - - 2005
Diastolic time fraction (DTF) has been recognized as an important determinant for subendocardial perfusion, but microsphere studies in which DTF was the independent variable are practically absent. In 21 anesthetized goats, the left coronary main stem was artificially perfused at controlled pressure. DTF was varied by pacing the heart, vagus ...
Verhoeff Bart-Jan - - 2005
BACKGROUND: Coronary microvascular resistance during maximal hyperemia is generally assumed to be unaffected by percutaneous coronary interventions (PCIs). We assessed a velocity-based index of hyperemic microvascular resistance (h-MR(v)) by using prototypes of a novel, dual-sensor (Doppler velocity and pressure)-equipped guidewire before and after PCI to test this hypothesis. METHODS AND ...
Mohl Werner - - 2005
Beating heart surgery leaves myocardial areas underperfused and rendered ischemic during brief coronary artery occlusions. In a recent meta-analysis in experimental myocardial infarction, intermittent coronary sinus occlusion (ICSO) proved valid to salvage ischemic myocardium by 30%. Moreover, benefit of this effect can be optimised using coronary venous pressure data. The ...
Shipley Robert D - - 2005
OBJECTIVE: Aging decreases coronary blood flow and maximal reserve capacity. Impaired blood flow capacity may be related to an increased vasoconstrictor capacity of coronary resistance vessels. This study tested the hypothesis that aging increases the vasoconstrictor responsiveness of coronary arterioles isolated from myocardium of young (4 months) and old (24 ...
Balachandran K P - - 2004
OBJECTIVE: To evaluate the relation between pressure derived coronary collateral flow (PDCF) index and angiographic TIMI (thrombolysis in myocardial infarction) myocardial perfusion (TMP) grade, angiographic collateral grade, and subsequent recovery of left ventricular function after rescue percutaneous coronary intervention (PCI) for failed reperfusion in acute myocardial infarction. METHODS: The pressure ...
de Marchi Stefano F - - 2005
AIMS: The aim of our study in patients with coronary artery disease (CAD) and present, or absent, myocardial ischaemia during coronary occlusion was to test whether (i) left ventricular (LV) filling pressure is influenced by the collateral circulation and, on the other hand, that (ii) its resistance to flow is ...
Nair Girish V - - 2005
Pulse pressure, an index of large artery stiffness, has been associated with coronary events. However, mechanisms for this association remain unclear. In this study, we examined the relationship between pulse pressure and the progression of coronary atherosclerosis and the effects of hormone replacement therapy (HRT) on pulse pressure in postmenopausal ...
Galderisi Maurizio - - 2004
OBJECTIVE: To examine the effects of nebivolol, a beta-blocker with nitroxide-mediated vasodilating properties, on coronary flow reserve (CFR) in patients with uncomplicated arterial hypertension. DESIGN, SETTING AND PATIENTS: Fourteen newly diagnosed, never-treated, World Health Organization grade I-II hypertensive patients (male/female, 10/4; mean age, 47 years), free of coronary heart disease, ...
Holmes David - - 2004
The disappearance of a dichrotic notch on the peripheral arterial pulse wave has been associated with significant peripheral vascular disease. A similar observation has not been reported in the distal coronary pressure waveform. The purpose of this study was to investigate the significance of a coronary pressure notch distal to ...
Jasti Venu - - 2004
BACKGROUND: Intravascular ultrasound (IVUS) is being used to assess the significance of a left main coronary artery stenosis (LMCS). However, the cutoff values of IVUS parameters at which to predict a fractional flow reserve (FFR) of 0.75 are unknown. METHODS AND RESULTS: In 55 patients with an angiographically ambiguous LMCS, ...
Aarnoudse Wilbert - - 2004
BACKGROUND: Whether minimal microvascular resistance of the myocardium is affected by the presence of an epicardial stenosis is controversial. Recently, an index of microcirculatory resistance (IMR) was developed that is based on combined measurements of distal coronary pressure and thermodilution-derived mean transit time. In normal coronary arteries, IMR correlates well ...
Guido Maria Carolina - - 2004
Left ventricular hypertrophy following volume overload is regarded as an example of cardiac remodeling without increased fibrosis accumulation. However, infarction is associated with increased fibrosis within the noninfarcted, hypertrophied myocardium, particularly in the subendocardial regions. It is conceivable to suppose that, as also occurs postinfarction, low coronary driving pressure may ...
Poston Robert S - - 2004
BACKGROUND: By minimizing tissue ischemia, continuous perfusion (CP) during organ transport may increase the safety of "marginal donors." My colleagues and I investigated whether an analysis of donor heart viability predicts recovery of grafts challenged with a 24-hour preservation interval. METHODS: Dog hearts underwent cold static storage (CS) for 8 ...
Meier Jens - - 2004
Critical coronary stenosis (critical CS) alone does not lead to an alteration of fractal dimension (D) under resting conditions in a pig model, indicating undisturbed local myocardial perfusion. If critical CS is combined with hypovolemic anemia the resulting hypotension leads to a significant decline of D. The mechanisms involved in ...
Claessens Tom E - - 2004
Fractional flow reserve (FFR) is a commonly used index to assess the functional severity of a coronary artery stenosis. It is conventionally calculated as the ratio of the pressure distal (Pd) and proximal (Pa) to the stenosis (FFR= Pd/Pa). We hypothesize that the presence of a zero flow pressure (Pzf), ...
Tajaddini Azita - - 2005
Despite their advantages, percutaneous coronary interventional procedures are less effective in diabetic patients. Changes in the mechanical properties of vascular walls secondary to long-term hyperglycemia as well as other factors such as age may influence coronary distensibility. This investigation is aimed at deciphering the extent of these effects on distensibility ...
Buus Niels H - - 2004
Hypertension is associated with reduced coronary vasodilatory capacity, possibly caused by structural changes in the coronary resistance vessels. Because vasodilatory treatment may correct abnormal structure better than nonvasodilating treatment, we compared whether long-term angiotensin-converting enzyme (ACE) inhibition has a greater effect on coronary reserve and cardiovascular structure than beta-blockade in ...
Koller Akos - - 2004
The role of metabolic factors derived from cardiac muscle in the development of reactive hyperemia after brief occlusions of the coronary circulation seems to be well established. However, the contribution of occlusion-induced changes in hemodynamic forces to eliciting reactive hyperemia is less known. We hypothesized that in isolated coronary arterioles ...
Zhang Jian - - 2004
BACKGROUND: It has recently been shown that mitochondrial aldehyde dehydrogenase 2 (mtALDH) catalyzes the formation of 1,2-glyceryl dinitrate and nitrite from nitroglycerin (glyceryl trinitrate [GTN]) within mitochondria, leading to production of cGMP and vasorelaxation. However, whether this mechanism operates in the systemic and coronary beds that subserve the antianginal action ...
Geven Maartje C F - - 2004
With the development of clinical diagnostic techniques to investigate the coronary circulation in conscious humans, the in vitro validation of such newly developed techniques is of major importance. The aim of this study was to develop an in vitro model that is able to mimic the coronary circulation in such ...
Smith Nicolas P - - 2004
An anatomically based computational model of coronary blood flow, coupled to cardiac mechanics, is verified with experimental data and used to investigate the mechanisms by which myocardial contraction inhibits coronary blood flow. From finite deformation mechanics solutions the regional variation in intramyocardial pressure (IMP) exerted on coronary vessels embedded in ...
Merrill Gary F - - 2004
The hypothesis that acetaminophen can reduce necrosis during myocardial infarction was tested in male dogs. Two groups were studied: vehicle- (n=10) and acetaminophen-treated (n=10) dogs. All dogs were obtained from the same vendor, and there were no significant differences in their ages (18 +/- 2 mo), weights (24 +/- 1 ...
D'Ancona Giuseppe - - 2004
OBJECTIVE: Aim of this study was to investigate modifications of coronary grafts flow during different pacing modalities after CABG. MATERIALS AND METHODS: Two separate prospective studies were conducted in patients undergoing CABG and requiring intraoperative epicardial pacing. In a first study (22 patients) coronary grafts flows were measured during dual ...
Bratkovsky S - - 2004
AIM: Langendorff-perfused murine hearts are increasingly used in cardiovascular research, but coronary cardiovascular haemodynamics vary considerably from one research group to another. The aim of this study was to establish an isolated, retrogradely perfused mouse heart preparation for the simultaneous measurement of left ventricular haemodynamics and of coronary flow (CF). ...
Fearon William F - - 2004
BACKGROUND: The effect of epicardial artery stenosis on myocardial microvascular resistance remains controversial. Recruitable collateral flow, which may affect resistance, was not incorporated into previous measurements. METHODS AND RESULTS: In an open-chest pig model, distal coronary pressure was measured with a pressure wire, and the apparent minimal microvascular resistance was ...
Cattin Philippe - - 2004
OBJECTIVES: To characterize remaining coronary artery motion of beating pig hearts after stabilization with an 'Octopus' using an optical remote analysis technique. METHODS: Three pigs (40, 60 and 65 kg) underwent full sternotomy after receiving general anesthesia. An 8-bit high speed black and white video camera (50 frames/s) coupled with ...
Lamberts Regis R - - 2004
Ischemic heart disease is more apparent in the subendocardial than in subepicardial layers. We investigated coronary pressure-flow relations in layers of the isolated rat left ventricle, using 15 microm microspheres during diastolic and systolic arrest in the vasodilated coronary circulation. A special cannula allowed for selective determination of left main ...
Preumont Nicolas - - 2004
Angiotensin II, via AT1 receptors plays a key role in endothelial dysfunction and therefore, in atherogenesis. In order to assess whether long-term blockade of these receptors improve peripheral and coronary endothelial function, 13 patients were treated by candesartan cilexetil (AT2B, 16 mg/d in 10 patients and 8 mg in 3). ...
Rozenberg V D - - 2004
We performed a pathomorphological study of 200 hearts with cicatricial changes from patients died from hypertensive disease. Most postinfarction scars in men were transmural and localized in the anterior and posterior wall of the left ventricle and in the interventricular septum. Non-transmural scars were revealed in the lateral wall (primarily ...
Fearon William F - - 2004
Delivery of angiogenic factors to ischemic myocardium remains a practical challenge. We evaluated the efficiency and efficacy of delivery of fibroblast growth factor-2 (FGF-2) protein via high-pressure retrograde injection into the anterior interventricular vein (AIV) in a porcine model of chronic myocardial ischemia. Labeled FGF-2 protein was delivered to the ...
Washio Masakazu - - 2004
BACKGROUND: Hypertension is an important risk factor of coronary heart disease. A new guidelines for hypertension prevention and management in The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure in the United States recommended lifestyle modification or medical treatment for subjects ...
Capp C L - - 2004
In prior studies in man, we have demonstrated that pressure-induced hyperemia lasts for prolonged periods as compared to the short-term hyperemia created by proximal arterial occlusion. We have analyzed this phenomenon in our well-studied rat model of skin blood flow. Skin blood flow was measured using laser Doppler techniques in ...
Parham Walter A - - 2004
BACKGROUND: Sodium nitroprusside is one of several agents considered effective for treating the no-reflow phenomenon during acute coronary interventions. However, the coronary hyperemic dose responses and systemic hemodynamic effects of intracoronary nitroprusside have yet to be determined in humans. The purpose of this study was to compare the hyperemic and ...
Beltran E - - 2004
Sodium chloride (5%) and some antioxidants (400 ppm rosemary extract; 2000 ppm acerola extract; 50 ppm ethylenediamine tetraacetic acid (EDTA); 1,000, 2,000, and 5,000 pm of sodium hexametaphosphate or 5 and 10% egg white powder) were added to minced chicken. From these mixtures, slurries were made by mixing with water ...
Siebes Maria - - 2004
BACKGROUND: Lack of high-fidelity simultaneous measurements of pressure and flow velocity distal to a coronary artery stenosis has hampered the study of stenosis pressure drop-velocity (DeltaP-v) relationships in patients. METHODS AND RESULTS: A novel 0.014-inch dual-sensor (pressure and Doppler velocity) guidewire was used in 15 coronary lesions to obtain per-beat ...
Takeuchi Masaaki - - 2004
OBJECTIVES: The study was done to determine potential utility of measuring coronary flow velocity (CFV) by transthoracic Doppler echocardiography (TTDE) during intra-aortic balloon pumping (IABP). BACKGROUND: Use of IABP has been shown to increase CFV assessed by an invasive technique. The CFV in the left anterior descending coronary artery (LAD) ...
Agnisola C - - 2004
This study was designed to investigate the short-term effects of cortisol and 17-beta-estradiol on the intact coronary tree of rainbow trout (Oncorhynchus mykiss). A non-working, isolated, and perfused heart preparation was used. The coronary pressure was monitored together with the coronary flow in order to calculate the coronary resistance. The ...
Jang S - - 2004
This work presents an alternative return of spontaneous circulation (ROSC) estimate using indirectly induced presumption that coronary perfusion pressure (CPP) correlates with the extracted parameter from the ventricular fibrillation (VF) ECG signal. In past studies, it is revealed that successful cardiopulmonary resuscitation (CPR) needs at least 30 approximately 40 mmHg ...
Brosh David - - 2004
Intracoronary pressure measurements and the determination of fractional flow reserve (FFR) after percutaneous coronary intervention (PCI) predict adverse events. Coronary lesions may impair the transmission of pressure waves across a stenosis, potentially acting as a high-frequency filter. The pulse transmission coefficient (PTC) is a nonhyperemic parameter that calculates the transmission ...
Gellman Joel - - 2004
A nitric oxide (NO)-related defect may contribute to abnormal coronary sympathetic responses that can cause ischemia in patients with endothelial dysfunction. Because L-arginine, the NO synthase (NOS) precursor, augments NO bioactivity, we hypothesized that L-arginine would improve dysfunctional coronary sympathetic responses. Eleven patients with atherosclerosis or its risk factors were ...
Voudris Vassilis - - 2003
BACKGROUND: Changes in mean blood pressure (MBP) alter coronary blood flow (CBF). We evaluated the acute effects of three hypotensive medications on CBF parameters in angiographically normal coronary arteries. METHODS: We performed CBF measurements using the Doppler wire at rest and during hyperemia produced by intracoronary adenosine (18 microg) as ...
Agnisola C - - 2003
Basal performance, volume loading response and oxygen consumption were determined in a resistance-headed preparation of the isolated trout heart. Two groups of hearts were used: the +CF group, in which the coronary vascular tree was perfused with a flow directly related to the pressure generated by the heart, and the ...
Cin V Gökhan - - 2003
Intravascular ultrasound imaging can detect intimal thickening and is suitable for detection of early atherosclerosis, which cannot be detected by conventional angiography. The aim of the present study was to investigate the epicardial coronary morphology and intracoronary pressure in relation to slow coronary flow (SCF). The study population consisted of ...
Boersma Eric - - 2003
BACKGROUND: Elevated blood pressure is associated with an impaired prognosis in patients with established coronary heart disease. Adequate blood pressure control is therefore of utmost importance. We report on two successive European surveys that evaluated whether the goals given in recommendations on secondary prevention are achieved. METHODS: The first European ...
Houghton Jan Laws - - 2003
Excess coronary heart disease morbidity and mortality among African Americans remains an important yet unexplained public health problem. We hypothesized that adverse outcome is in part due to intrinsic or acquired abnormalities in coronary endothelial function and vasoreactivity. We compared dose-response curves relating changes in coronary blood flow and epicardial ...
Hamza Leila H - - 2003
The objective of this study was to determine the effect of passive myocardium on the coronary arteries under distension and compression. To simulate distension and compression, we placed a diastolic-arrested heart in a Lucite box, where both the intravascular pressure and external (box) pressure were varied independently and expressed as ...
Malo Olivier - - 2003
Coronary endothelial dysfunction in left ventricular hypertrophy (LVH) can reduce myocardial perfusion and result in an impaired global LV function. The objective of this study was to characterize the specific alterations of endothelial signal transduction of coronary arteries in a swine LVH model. Aortic banding was performed 3 cm above ...
Casella G - - 2003
BACKGROUND: Fractional flow reserve (FFR) is a measure of coronary stenosis severity that is based on pressure measurements obtained at maximal hyperemia. Therefore, achievement of maximal vasodilatation of the coronary microcirculation is a prerequisite for the measurement of FFR. The study was designed to address the hypothesis that intracoronary adenosine ...
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