This study was designed to investigate the site of vascular endothelial growth factor (VEGF)-induced vasodilation in the systemic and coronary vasculature. Intracoronary infusion of VEGF in Yorkshire pigs resulted in a significant drop in the mean arterial blood pressure, with a decline in the left ventricular left end-diastolic pressure, and ...

Extensive research suspecting an association between plasma levels of dehydroepiandrosterone and the risk of coronary heart disease has not been conclusive. The present study was designed to investigate the effect of dehydroepiandrosterone on the coronary circulation and to determine the mechanisms involved. In prepubertal pigs of both sexes anaesthetized with ...

We developed a coronary active perfusion system (CAPS) to avoid myocardial ischemia during off-pump coronary artery bypass (OPCAB). The purpose of this study was to determine the optimal timing of CAPS perfusion, and to investigate any adverse effects when it is driven within the systolic phase. Twenty-four pigs were divided ...

We report a comparison of the effects of myocardial infarction in dogs and sheep using sequential ligation of the left anterior descending artery (LAD) and its diagonal branch (DA), with hemodynamic, ultrasonographic and pathological evaluations. Five animals were used in each group. After surgical preparation, the LAD was ligated at ...

OBJECTIVE: hemolysin has been implicated as an important pathogenic factor in extraintestinal infections including sepsis. We investigated the effects of coronary administration of hemolysin on cardiac function in isolated rat hearts perfused at constant flow. DESIGN: Prospective, experimental study. SETTING: Research laboratory at a university hospital. SUBJECTS: Isolated hearts from ...

Most arterial mechanics studies have focused on excised non-coronary vessels, with few studies validating the application of ex-vivo results to in-vivo conditions. A method was developed for testing the mechanical properties of intact left anterior descending coronary arteries under a variety of conditions. Vascular deformation and pressure were simultaneously measured ...

It was tested whether a bolus injection of 10 ml radiographic contrast medium (iopromide vs. iohexol), compared to a 10 ml NaCl bolus and administered into the left anterior descending artery (LAD) of farm pigs, influenced the tissue pO2 in the territory of this artery. The radiographic contrast media and ...

BACKGROUND: Hemodynamic instability remains a prominent concern for surgeons performing coronary surgery without cardiopulmonary bypass. The purpose of this study was to further elucidate the mechanism of hemodynamic instability by comparing vacuum stabilization to mechanical stabilization. METHODS: Four 60-kg swine were placed under general anesthesia. A median sternotomy incision was ...

In 50 patients undergoing percutaneous transluminal coronary angioplasty because of chronic angina pectoris, a collateral flow index (CFI) was determined at the start and the end of two 1-min coronary occlusions, randomly accompanied by a resting state or a 3-min dynamic handgrip exercise (DHE). CFI expressing collateral flow relative to ...

The circulation in the left and right coronary beds in pressure overload-induced left ventricular (LV) hypertrophy was studied in Wistar male rats (n=6/group) that were subjected to abdominal aortic constriction or to sham-operation. From 3 to 6 weeks after surgery, the animals with aortic constriction received vehicle or 0.01, 0.1, ...

Blood pressure (BP) is poorly controlled in many countries. Poor compliance was suggested as the main cause for poor BP control. The purpose of this study was to examine the association between compliance and the control of both casual blood pressure (BP) and 24-hr ambulatory BP in a Japanese elderly ...

The aim of this study was to assess the relation between coronary blood flow and left ventricular (LV) myocardial diastolic dysfunction in arterial hypertension. The study population included 30 hypertensive patients who were free of coronary artery disease and pharmacologic therapies. They underwent standard Doppler echocardiography and color tissue Doppler ...

Pressure-based fractional flow reserve (FFR) is used clinically to evaluate the functional severity of a coronary stenosis, by predicting relative maximal coronary flow (Q(s)/Q(n)). It is considered to be independent of hemodynamic conditions, which seems unlikely because stenosis resistance is flow dependent. Using a resistive model of an epicardial stenosis ...

Although measurements of the fractional flow reserve (FFR) provide accurate information on functional stenosis severity in many conditions, it remains unknown whether the extent of the vascular territory distal to the target lesion influences FFR calculations. Across a total of 16 selected coronary lesions intracoronary pressure during maximal hyperaemia was ...

10.1152/ajpheart.00925. 2001.-Parathyroid hormone-related peptide (PTHrP) is expressed throughout the cardiovascular system and is able to dilate vessels. This study investigated whether mechanical forces generated by changes in regional perfusion influence PTHrP release from the coronary vascular bed. Experiments were performed in vitro on saline-perfused rat hearts or isolated coronary endothelial ...

BACKGROUND: Enhanced external counterpulsation (EECP) is a noninvasive, pneumatic technique that provides beneficial effects for patients with chronic, symptomatic angina pectoris. However, the physiological effects of EECP have not been studied directly. We examined intracoronary and left ventricular hemodynamics in the cardiac catheterization laboratory during EECP. METHODS AND RESULTS: Ten ...

This study was performed to compare the effectiveness of external thoracic compressions with and without intra-aortic occlusion balloon with capnography and coronary and cerebral perfusion pressure (CPP) in the normothermic and traumatic-less cardiopulmonary arrest provoked by a ventricular fibrillation in pigs. This was an experimental study (cross-over study) in 14 ...

BACKGROUND: The reduction of coronary flow reserve (CFR) found in arterial hypertension may be due to changes in afterload, left ventricular (LV) structure, and metabolic factors. Also, insulin-like growth factor-1 (IGF-1) may be associated with the magnitude of CFR in relation to its modulating action on cardiac and endothelial function. ...

BACKGROUND: Although it was reported that the pulsatility of ascending aortic pressure is closely related to restenosis after percutaneous transluminal coronary angioplasty (PTCA), it is not known whether the reflection period of ascending aortic pressure can predict restenosis after PTCA. The purpose of this study was to evaluate whether reflection ...

We studied twelve patients with hypertensive left ventricular hypertrophy (LVH), 10 patients with hypertrophic cardiomyopathy (HCM) and 10 control subjects to examine the differences in coronary blood flow (CBF) dynamics between patients with hypertensive LVH and those with HCM. All subjects had normal coronary arteriograms. Measurements of CBF using Doppler ...

BACKGROUND: Pulse pressure and aortic stiffness are both predictors of coronary artery disease. Whether these parameters are directly related to coronary structural alterations has never been studied. METHODS: From September 1999 to September 2000, the following data were collected from 99 eligible patients: invasive intra-aortic systolic and diastolic blood pressures ...

BACKGROUND: Both coronary blood flow velocity reserve (CFVR) and myocardial fractional flow reserve (FFR) are used to evaluate the hemodynamic severity of coronary lesions. However, discordant results between CFVR and FFR have been observed in 25% to 30% of intermediate coronary lesions. An index of stenosis resistance based on a ...

BACKGROUND: To characterize the impact of brain death (BD) on endothelial dysfunction after cardiac transplantation we investigated coronary circulation and vasomotor function in a canine model. METHODS: Left ventricular pressure-volume data (conductance catheter) and coronary blood flow (CBF) were monitored continuously. Endothelium-dependent vasodilatation after acetylcholine and endothelium-independent vasodilation after sodium ...

OBJECTIVE: To compare sodium nitroprusside (SNP)-induced hypotension with desflurane-induced hypotension for the effects on myocardial blood flow and tissue oxygenation in dogs. DESIGN: Prospective, randomized, crossover, nonblinded. SETTING: University teaching hospital. PARTICIPANTS: Male nonpurpose-bred hounds (n = 8). INTERVENTIONS: Dogs were anesthetized with 8% desflurane. Catheters were inserted into the ...

OBJECTIVES: We assessed the feasibility and reproducibility of the instantaneous diastolic coronary flow velocity-pressure gradient relation to characterize different degrees of coronary stenoses. BACKGROUND: Assessment of the hemodynamic significance of coronary stenoses can be difficult. Using sensor-tipped guidewires, various physiologic indexes can be determined in the catheterization laboratory. Each of ...

BACKGROUND: This study investigated the hemodynamic changes in patients undergoing multiple vessel beating heart coronary revascularization in the presence or absence of an intracoronary shunt. METHODS: Forty patients were randomized to off-pump with a shunt (n = 20) or with the proximal coronary artery occluded by a soft snare (n ...

OBJECTIVE: To observe the characteristics of coronary microvascular lesions (CML) in the autopsied elderly cases with hypertensive left ventricular hypertrophy (LVH) and the difference of CML among the groups of essential hypertension (EHT), coronary heart disease (CHD) and diabetes (NIDDM) also with LVH. METHODS: A retrospective study was performed in ...

The effects of aqueous leaf extract of Azadirachta indica were evaluated on isolated prefused frog and rabbit heart. Dose dependent negative inotropic and chronotropic effects were observed in both the heart preparation. An increase in coronary blood flow in isolated rabbit heart was observed. The effects were not blocked by ...

OBJECTIVES: We sought to test the hypothesis that the pulse transmission coefficient (PTC) can serve as a nonhyperemic physiologic marker for the severity of coronary artery stenosis in humans. BACKGROUND: Coronary lesions may impair the transmission of pressure waves across a stenosis, potentially acting as a low-pass filter. The PTC ...

Although the pressure gradient between the normal and stenotic vascular regions is known to be the most important factor for collateral vessel development, factors which are responsible for variations among patients with ischemic heart disease are not well known. Likewise, it is still not clear whether diabetes mellitus (DM) has ...

The aim of this study was to investigate mitochondrial alterations in an animal model of chronic myocardial ischemia in rats obtained by surgical constriction of the left coronary artery. Resting coronary blood flow was measured using the fluorescent microsphere technique. Contractile function, defined by rate-pressure product, and myocardial oxygen consumption ...

BACKGROUND: Currently, the detection of noncritical coronary stenoses requires some form of stress. We hypothesized that these stenoses can be detected at rest without recourse to stress by assessing adaptive changes that occur distally in the microcirculation. METHODS AND RESULTS: Phasic changes in myocardial video intensity (VI) were measured at ...

The effects of <I>Morinda citrifolia</I> (Rubiceace) extract on coronary perfusion pressure, contractility and heart rate of isolated rats hearts were studied by using the technique of Langendorff system. Sodium nitroprusside (SNP) was used as a positive control and standard while saline was used as negative control. The extract at doses ...

We investigated the relationship between coronary perfusion pressure (CPP) and myocardial contractility and the effects of an acute elevation of right atrial pressure (RAP) on this relationship in an experimental model of Fontan circulation in 6 anesthetized open-chest dogs with isolated perfused coronary arteries. The relationship between CPP and Ees ...

OBJECTIVES: Cocaethylene is a toxic metabolite of cocaine formed in the presence of ethanol. Though cocaine causes coronary vasoconstriction, cocaethylene's effects on coronaryflow are unknown. The aim of our study was to describe cocaethylene 's effects on coronary flow and cardiac function. METHODS: Sixteen alpha-chloralose anesthetized dogs were monitored with ...

A dynamic simulation was performed in order to study the high zero-flow pressure phenomenon by using an electronic model of the coronary vessel. The objective of this study was to establish a relationship between the diastolic arterial pressure and diastolic arterial flow. The simulated study showed that this relationship is ...

RATIONALE AND OBJECTIVES: The systemic tolerance thresholds of modern low-osmolar x-ray contrast media (CM) are similarly high, but their effects on the cardiovascular system and on the coagulation differ. The aim of this study was to comparatively evaluate the cardiovascular tolerability of iopromide, ioxaglate, and iosmin, and of a novel ...

The routine use of sensor-tipped guide wires for the assessment of functional coronary lesion severity has become widespread in the catheterization laboratory. The physiological parameters derived from pressure or flow velocity measurements, fractional flow reserve, relative and absolute coronary blood flow velocity reserve show a high agreement with noninvasive stress ...

BACKGROUND: Collateral circulation can maintain myocardial function and viability in chronic total coronary occlusion (TCO). The present study evaluates the relation of myocardial function and duration of occlusion to collateral function. METHODS AND RESULTS: A total of 50 patients underwent a successful recanalization of a TCO (>4 weeks' duration). Collateral ...

Fractional flow reserve (FFR) has been applied with success as a lesion-specific functional indicator of stenosis severity, at least in patients with normal microcirculation. This study sought to assess the reliability of FFR calculations in patients with associated microvascular dysfunction (e.g., post myocardial infarction, or post-MI). First, the effect of ...

Clinical reports suggest that intracoronary delivery of adenoviruses encoding angiogenic growth factors, or their transactivators, has a therapeutic benefit. However there has not been a systematic assessment of the transfection efficiency of this technique in vivo. In rabbits we investigated the efficiency of myocardial gene transfer following intracoronary infusion of ...

OBJECTIVE: The increase in coronary blood flow (CBF) in response to endothelium-dependent vasodilators is reduced in congestive heart failure (CHF) suggesting endothelial dysfunction. However, increases in extravascular compressive forces secondary to elevated left ventricular diastolic pressure (LVEDP) in CHF might contribute to this abnormality. METHODS: We measured CBF responses to ...

We investigated the influence of stretch on regional hemodynamic parameters of the septal circulation. We used a similar experimental setup and mathematical model, as described previously (14). Five ventricular septa were isolated from anesthetized dogs, sutured to a biaxial stretching apparatus, and perfused with an oxygenated perfluorochemical emulsion at maximal ...

The effects of the endothelin ET(A), (BQ-123) and endothelin ET(A/B) (PD161721) receptor antagonists were investigated on ischaemia-induced arrhythmias and on the maximum following frequency. The study was carried out in Langendorff perfused rat hearts subjected to coronary artery occlusion in which the severity of arrhythmias, coronary perfusion pressure and heart ...

It is known that contractile reserve may be blunted if perfusion and coronary flow reserve are reduced. Thus, it is conceivable that the predictive accuracy of dobutamine echocardiography may differ according to perfusion tracer uptake. The aim of this study was therefore to assess the relationship between the level of ...

The increase in right ventricular systolic pressure observed in vivo after the administration of mercury opposes to the idea that the metal depresses the cardiac pump performance. We then investigated the effects of HgCl(2) (0.1 to 2.5 microM) on the contractile activity of the right ventricular myocardium, measuring isometric and ...

The aim of this study is to investigate the value of hemodynamic changes induced by carotid sinus massage (CSM) on the diagnosis of coronary artery disease (CAD). A total 108 patients (mean age, 54 +/- 10 years, range 33-70) who had no significant stenosis in the carotid artery by duplex ...

The present study seeks to estimate the difference between coronary zero flow pressure (Pzf) by analysis of the baseline pressure-flow relationship and the Pzf calculated during a long diastole in humans. Although Pzf is likely to provide meaningful information about the characteristics of coronary circulation, there are no available data ...

Arterial stenosis is known to be one of the most serious cardiovascular diseases. Angiographical estimation of arterial stenosis provides limited information on the severity of the occlusion and the flow of blood through it. Hemodynamical assessment of the flow and pressure behaviour, is known to be clinically important. Hemodynamically based ...

The angiographic prevalence, clinical predictors, and sensitivity and specificity of a bilateral arm blood pressure differential for predicting proximal left subclavian artery stenosis were established in 492 patients undergoing cardiac catheterization. Seventeen subjects (3.5%) in the overall population and nine subjects (5.3%) with potential surgical coronary disease had proximal left ...