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Coronary Flow (coronary + flow)

Distribution by Scientific Domains

Medical Sciences	93%
Life Sciences	6%

Distribution within Medical Sciences

Cardiovascular Disease	44%
Pharmacology & Pharmaceutical Medicine	20%

Kinds of Coronary Flow

normal coronary flow

Terms modified by Coronary Flow

coronary flow reserve

coronary flow velocity

coronary flow velocity reserve

Selected Abstracts

Effect of Sildenafil Citrate (Viagra) on Coronary Flow in Normal Subjects

ECHOCARDIOGRAPHY, Issue 1 2008
Fuminobu Ishikura M.D.
Background: The purpose of this study was to evaluate the effect of sildenafil citrate (Viagra) on coronary function in normal subjects. Methods: The study assessed mean blood pressure, left anterior descending coronary artery (LAD) flow, and echocardiographic variables before and 30 and 60 minutes after taking 50 mg of sildenafil citrate. The mean velocity of LAD flow was assessed with Doppler flow imaging. The study subjects were 6 healthy male volunteers (mean age 37 years). Results: The mean velocity of LAD flow increased 60 minutes after taking sildenafil citrate, but there were no other changes. Two volunteers felt mild flashing and one had mild headache during the study. Conclusion: Sildenafil citrate caused vasodilatation in a normal coronary artery without systemic pressure drops. These results suggest that the agent itself did not have negative effects on the heart in normal subjects. [source]

Relationship between Slow Coronary Flow and Left Atrial Appendage Blood Flow Velocities

ECHOCARDIOGRAPHY, Issue 1 2007
Recep Demirbag M.D.
Aims: This study was undertaken to assess whether slow coronary flow (SCF)is related to low left atrial appendage (LAA) blood flow velocities. Methods: Study subjects consist of 44 patients with SCF and 11 volunteer subjects with normal coronary angiogram. The diagnosis of SCF was made using the TIMI frame count method. The blood flow velocities were obtained by placing a pulsed-wave Doppler sample volume inside the proximal third of the LAA. Results: The mean LAA emptying velocities (MEV)were significantly lower in patients than control subjects (34.5 ± 9.9 cm/sec vs 84.0 ± 12.1 cm/sec; P < 0.001). In bivariate analysis, significant correlation was found between MEV, and systolic pulmonary venous flow, mean TIMI frame count, deceleration time, and isovolumetric relaxation time (P < 0.05). By multiple linear regression analysis, mean TIMI frame count (ß=,0.865, P < 0.001) was identified as independent predictors of MEV. Conclusion: This study indicates that SCF phenomenon may be related to low LAA blood flows. [source]

Coronary Hemodynamics and Myocardial Oxygen Consumption During Support With Rotary Blood Pumps

ARTIFICIAL ORGANS, Issue 1 2009
Peter Voitl
Abstract Mechanical support offered by rotary pumps is increasingly used to assist the failing heart, although several questions concerning physiology remain. In this study, we sought to evaluate the effect of left-ventricular assist device (VAD) therapy on coronary hemodynamics, myocardial oxygen consumption, and pulmonary blood flow in sheep. We performed an acute experiment in 10 sheep to obtain invasively measured coronary perfusion data, as well as pressure and flow conditions under cardiovascular assistance. A DeBakey VAD (MicroMed Cardiovascular, Inc., Houston, TX, USA) was implanted, and systemic and coronary hemodynamic measurements were performed at defined baseline conditions and at five levels of assistance. Data were measured when the pump was clamped, as well as under minimum, maximum, and moderate levels of assistance, and in a pump-off condition where backflow occurs. Coronary flow at the different levels of support showed no significant impact of pump activity. The change from baseline ranged from ,10.8% to +4.6% (not significant [n.s.]). In the pulmonary artery, we observed a consistent increase in flow up to +4.5% (n.s.) and a decrease in the pulmonary artery pressure down to ,14.4% (P = 0.004). Myocardial oxygen consumption fell with increasing pump support down to ,34.6% (P = 0.008). Left-ventricular pressure fell about 52.2% (P = 0.016) as support was increased. These results show that blood flow in the coronary arteries is not affected by flow changes imposed by rotary blood pumps. An undiminished coronary perfusion at falling oxygen consumption might contribute to cardiac recovery. [source]

Reproducibility of coronary lumen, plaque, and vessel wall reconstruction and of endothelial shear stress measurements in vivo in humans

CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 1 2003
Ahmet U. Coskun PhD
Abstract The purpose of this study was to assess the reproducibility of an in vivo methodology to reconstruct the lumen, plaque, and external elastic membrane (EEM) of coronary arteries and estimate endothelial shear stress (ESS). Ten coronary arteries without significant stenoses (five native and five stented arteries) were investigated. The 3D lumen and EEM boundaries of each coronary artery were determined by fusing end-diastolic intravascular ultrasound images with biplane coronary angiograms. Coronary flow was measured. Computational fluid dynamics was used to calculate local ESS. Complete data acquisition was then repeated. Analysis was performed on each data set in a blinded manner. The intertest correlation coefficients for all arteries for the two measurements of lumen radius, EEM radius, plaque thickness, and ESS were r = 0.96, 0.96, 0.94, 0.91, respectively (all P values < 0.0001). The 3D anatomy and ESS of human coronary arteries can be reproducibly estimated in vivo. This methodology provides a tool to examine the effect of ESS on atherogenesis, remodeling, and restenosis; the contribution of arterial remodeling and plaque growth to changes in the lumen; and the impact of new therapies. Catheter Cardiovasc Interv 2003;60:67,78. © 2003 Wiley,Liss, Inc. [source]

Relationship between Slow Coronary Flow and Left Atrial Appendage Blood Flow Velocities

Ischaemia or reperfusion: which is a main trigger for changes in nitric oxide mRNA synthases expression?

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 9 2005
D. Pevni
Abstract Objective, To investigate alterations in endothelial nitric oxide synthase and inducible nitric oxide synthase mRNA expressions and nitric oxide release in the myocardium during ischaemia/reperfusion and determine whether these changes are ischaemic and/or reperfusion dependent. Materials and methods, Isolated rat hearts were perfused by a modified Langendorff system. Following 1 h of global cardioplegic ischaemia, left ventricle haemodynamic parameters were recorded at baseline and during 30 min of reperfusion. Levels of endothelial, inducible nitric oxide synthases mRNA expression and nitric oxide release were measured at baseline, after ischaemia and at 30 min of reperfusion. Results, Global cardioplegic ischaemia caused a significant depression of left ventricular function and a decrease of coronary flow. Postischaemic intensities of the endothelial nitric oxide synthase mRNA bands were significantly lower than at baseline (P < 0·01). There were no significant differences in endothelial nitric oxide synthase mRNA band intensities immediately after ischaemia compared to the end of reperfusion, nor between the intensities of inducible nitric oxide synthase mRNA bands at baseline, at end of ischaemia and at end of reperfusion. Nitric oxide in the myocardial effluent was below detectable levels at all measured points. Conclusion, Ischaemic injury causes down-regulation of endothelial nitric oxide synthase mRNA expression, which is then associated with reduction of coronary flow during reperfusion, representing one possible mechanism of ischaemia/reperfusion injury. We did not find expected elevations of inducible nitric oxide synthase mRNA expression during ischaemia or reperfusion and we suggest that ischaemia/reperfusion injury is not associated with nitric oxide overproduction. [source]

Cardiac and coronary function in the Langendorff-perfused mouse heart model

EXPERIMENTAL PHYSIOLOGY, Issue 1 2009
Melissa E. Reichelt
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 [Ca2+] and pacing rate on contractile function and responses to 20 min ischaemia followed by 45 min reperfusion. We also assessed the impact of strain, and tested the utility of the model in studying coronary function. Under normoxic conditions, hearts from 8-week-old male C57BL/6 mice (2 mm free perfusate [Ca2+], 420 beats min,1) exhibited 145 ± 2 mmHg left ventricular developed pressure (LVDP). Force development declined by ,15% (126 ± 5 mmHg) with a reduction in free [Ca2+] to 1.35 mm, and by 25% (108 ± 3 mmHg) with increased pacing to 600 beats min,1. While elevated heart rate failed to modify ischaemic outcome, the lower [Ca2+] significantly improved contractile recovery (by >30%). We detected minimal sex-dependent differences in normoxic function between 8 and 24 weeks, although age modified contractile function in males (increased LVDP at 24 versus 8 weeks) but not females. Both male and female hearts exhibited age-related reductions in ischaemic tolerance, with a significant decline in recovery evident at 16 weeks in males and later, at 20,24 weeks, in females (versus recoveries in hearts at 8 weeks). Strain also modified tolerance to ischaemia, with similar responses in hearts from C57BL/6, 129/sv, Quackenbush Swiss and FVBN mice, but substantially greater tolerance in BALB/c hearts. In terms of vascular function, baseline coronary flow (20,25 ml min,1 g,1) was 50,60% of maximally dilated flows, and coronary reactive and functional hyperaemic responses were pronounced (up to 4-fold elevations in flow in hearts lacking ventricular balloons). These data indicate that attention to age (and sex) of mice will reduce variability in contractile function and ischaemic responses. Even small differences in perfusion fluid [Ca2+] also significantly modify tolerance to ischaemia (whereas modest shifts in heart rate do not impact). Ischaemic responses are additionally strain dependent, with BALB/c hearts displaying greatest intrinsic tolerance. Finally, the model is applicable to the study of vascular reactivity, providing large responses and excellent reproducibility. [source]

No-Reflow Phenomenon Following Percutaneous Coronary Intervention for Acute Myocardial Infarction: Incidence, Outcome, and Effect of Pharmacologic Therapy

JOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 5 2010
F.A.C.C., F.A.C.P., SHEREIF H. REZKALLA M.D.
Background: No-reflow (NR) phenomenon is a well-known problem, often accompanying percutaneous coronary intervention for acute ST elevation myocardial infarction (STEMI). There are little data on effects of pharmacologic therapy on the resolution, outcome, and long-term natural history of NR. Objective: Retrospectively assess incidence, management, and prognosis of NR in a tertiary referral hospital. Methods: Study included patients with STEMI, treated with percutaneous coronary intervention (PCI). Effect of pharmacologic therapy and long-term outcome were assessed. NR was defined by thrombolysis in myocardial infarction (TIMI) < 3 or myocardial blush grade (MBG) < 3. Results: Of 347 identified subjects, NR occurred in 110 (32%) by TIMI and 198 (57%) by MBG. Higher incidence was identified in men versus women (34% vs. 25% by TIMI, P = 0.08; and 60% vs. 48% by MBG, P = 0.04). Pharmacologic therapy was equally effective in restoring normal flow, increasing TIMI score from 1.62 ± 0.07 to 2.78 ± 0.06 (P < 0.0001) and MBG score from 0.43 ± 0.08 to 2.09 ± 0.11 (P < 0.0001). Twenty-three percent who did not receive pharmacologic therapy developed clinical composite of congestive heart failure, cardiogenic shock, and/or death; only 9% of patients who received pharmacologic therapy developed this composite. Patients with severe NR despite treatment had poorer prognosis. Sixty-five percent of patients who survived and had repeat angiogram about 1.5 years later had spontaneous improvement in coronary flow by MBG. Conclusion: NR is common in STEMI. Treatment with nicardipine, nitroprusside, and verapamil are equally effective in improving flow. If not treated, prognosis is poor. (J Interven Cardiol 2010;23:429,436) [source]

Clinical Experience with a Novel Intracoronary Perfusion Catheter to Treat No-Reflow Phenomenon in Acute Coronary Syndromes

JOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 2 2010
GABRIEL MALUENDA M.D.
Background:,The no-reflow phenomenon is an often seen complication in patients presenting with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). This event is associated with poor prognosis and poses a therapeutic challenge. Methods:,This retrospective study cohort was composed of 30 patients who presented with ACS between September 2007 and April 2009, and developed no-reflow during subsequent PCI. The primary end-point was defined as normal Thrombolysis In Myocardial Infarction (TIMI) 3 flow with myocardial blush grade (MBG) ,2 or an increase in TIMI flow by ,2 grades with a MBG ,2 after intracoronary drug infusion via the ClearWay (CW) RX perfusion catheter. Results:,The population presented with a relatively high prevalence of cardiovascular risk factors. ST-elevation myocardial infarction was the most common presentation (60.0%), while 20% of the patients presented with cardiogenic shock. After intracoronary infusion of nicardipine or nitroprusside using the CW catheter, TIMI flow improved from the baseline in 19 cases (63.3%, P < 0.001), and 16 patients (53.3%, P < 0.001) achieved normal coronary flow at the end of the procedure. The rate of in-hospital death was 6.7% (2 cases). No clinical differences were noted between those patients who successfully achieved normal coronary flow and those with persistent no-reflow. Conclusion:,The infusion of intracoronary drugs using the novel perfusion CW RX catheter seems to be safe and could help to improve myocardial perfusion in a selected group of patients presenting with ACS who developed no-reflow during PCI. (J Interven Cardiol 2010;23:109-113) [source]

The effects of creatine on the retrogradely perfused isolated rat heart

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 1 2002
G. Kilian
Although the role of creatine in muscle metabolism is well understood, there is still uncertainty as to its effects at supplemented levels. With this in mind, this study was designed to investigate the direct effects of commercially available creatine on the isolated rat heart, retrogradely perfused and infused with varying concentrations of creatine (1.25, 2.5, 5 and 10 mM) to determine its effects on heart rate, coronary flow and ventricular pressure. Furthermore, tissue from these hearts was used to investigate the cardiotoxic potential of supplemented levels of creatine. Results indicate that creatine directly improves the functioning of the heart under normal conditions with respect to heart rate and ventricular pressure, but may be detrimental to the functioning of energy-deprived hearts. It also showed no cardiotoxic properties since it increased the baseline levels of adenosine triphosphate (ATP) and decreased the levels of isocitrate dehydrogenase (ICD), indicating a decrease in cellular death compared with non-supplemented control hearts. [source]

Targeted inhibition of the serotonin 5HT2A receptor improves coronary patency in an in vivo model of recurrent thrombosis

JOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 2 2010
K. PRZYKLENK
Summary.,Background: Release of serotonin and activation of serotonin 5HT2A receptors on platelet surfaces is a potent augmentative stimulus for platelet aggregation. However, earlier-generation serotonin receptor antagonists were not successfully exploited as antiplatelet agents, possibly owing to their lack of specificity for the 5HT2A receptor subtype. Objective: To assess whether targeted inhibition of the serotonin 5HT2A receptor attenuates recurrent thrombosis and improves coronary patency in an in vivo canine model mimicking unstable angina. Methods: In protocol 1, anesthetized dogs were pretreated with a novel, selective inverse agonist of the 5HT2A receptor (APD791) or saline. Recurrent coronary thrombosis was then initiated by coronary artery injury + stenosis, and coronary patency was monitored for 3 h. Protocol 2 was similar, except that: (i) treatment with APD791 or saline was begun 1 h after the onset of recurrent thrombosis; (ii) template bleeding time was measured; and (iii) blood samples were obtained for in vitro flow cytometric assessment of platelet responsiveness to serotonin. Results: APD791 attenuated recurrent thrombosis, irrespective of the time of treatment: in both protocols, flow,time area (index of coronary patency; normalized to baseline coronary flow) averaged 58,59% (P < 0.01) following administration of APD791 vs. 21,28% in saline controls. Moreover, the in vivo antithrombotic effect of APD791 was not accompanied by increased bleeding, but was associated with significant and selective inhibition of serotonin-mediated platelet activation. Conclusion: 5HT2A receptor inhibition with APD791, even when initiated after the onset of recurrent thrombosis, improves coronary patency in the in vivo canine model. [source]

Time-resolved flow measurement in the isolated rat heart: Characterization of left coronary artery stenosis

MAGNETIC RESONANCE IN MEDICINE, Issue 3 2003
Sascha Köhler
Abstract The investigation of flow behavior in coronary arteries is of great importance for an understanding of heart failure and heart regulation mechanisms. The purpose of the present study was to demonstrate that flow velocity can be quantified in the coronary arteries of the isolated rat heart with high-resolution phase contrast MRI. A phase contrast cine-FLASH imaging sequence was used for flow quantification with an in-plane resolution of 70 ,m and a slice thickness of 500 ,m. With time-resolved measurements, coronary flow over the heart cycle was analyzed. Furthermore, the flow behavior in coronary stenosis was investigated and the degree of stenosis was quantified with MR phase contrast imaging. To achieve the required spatial resolution and a satisfactory signal-to-noise ratio, the experiments were performed at 11.75 T. Magn Reson Med 50:449,452, 2003. © 2003 Wiley-Liss, Inc. [source]

Effect of oriental herbal prescription Guan-Xin-Er-Hao on coronary flow in healthy volunteers and antiapoptosis on myocardial ischemia-reperfusion in rat models

PHYTOTHERAPY RESEARCH, Issue 10 2007
Jianlei Zhao
Abstract Ischemic heart disease (IHD) is the main cause of death and a major public health problem in the world. The traditional herbal medicinal formula Guan-Xin-Er-Hao (GXEH) has been used in China and East Asia for the treatment of coronary heart disease, however, the underlying cardioprotection mechanisms remain unclear. To make clear the antiischemic mechanism involved, GXEH was orally administered to 15 healthy volunteers. Heart rates (HR), blood pressure and coronary flow (CF) velocity before and 1 h after a single oral dose of GXEH were observed and compared. It was demonstrated that the oral administration of GXEH increased CF acutely in a dose-dependent manner without modification of systemic hemodynamic parameters. Moreover, the myocardial protection function of GXEH was also experimentally examined in ischemia-reperfusion (I/R) rat models. Apoptosis was measured quantitatively by the terminal transferase UTP nick end-labeling (TUNEL) method and confirmed by caspase-3 activity. The infarct size and TUNEL-positive cells of GXEH-treated group (20 g/kg) were reduced significantly, which was consistent with the decreased caspase-3 activity. These suggest that GXEH protects hearts from ischemia injury by increasing CF and reduces infarct size by inhibiting myocardial apoptosis. Copyright © 2007 John Wiley & Sons, Ltd. [source]

ST-Segment Resolution Prior to Primary Percutaneous Coronary Intervention Is a Poor Indicator of Coronary Artery Patency in Patients with Acute Myocardial Infarction

ANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 2 2010
Niels J. Verouden M.D.
Background: The prognostic value of ST-segment resolution (STR) after initiation of reperfusion therapy has been established by various studies conducted in both the thrombolytic and mechanic reperfusion era. However, data regarding the value of STR immediately prior to primary percutaneous coronary intervention (PCI) to predict infarct-related artery (IRA) patency remain limited. We investigated whether STR prior to primary PCI is a reliable, noninvasive indicator of IRA patency in patients with ST-segment elevation myocardial infarction (STEMI). Methods: The study population consisted of STEMI patients who underwent primary PCI at our institution between 2000 and 2007. STR was analyzed in 12-lead electrocardiograms recorded at first medical contact and immediately prior to primary PCI and defined as complete (,70%), partial (70%, 30%), or absent (<30%). Results: In 1253 patients with a complete data set, STR was inversely related to the probability of impaired preprocedural flow (Pfor trend < 0.001). Although the sensitivity of incomplete (<70%) STR to predict a Thrombolysis in Myocardial Infarction (TIMI) flow of <3 was 96%, the specificity was 23%, and the negative predictive value of incomplete STR to predict normal coronary flow was only 44%. Conclusions: This study establishes the correlation between STR prior to primary PCI and preprocedural TIMI flow in STEMI patients treated with primary PCI. However, the negative predictive value of incomplete STR for detection of TIMI-3 flow is only 44% and therefore should not be a criterion to refrain from immediate coronary angiography in STEMI patients. Ann Noninvasive Electrocardiol 2010;15(2):107,115 [source]

A Mathematical Model to Evaluate Control Strategies for Mechanical Circulatory Support

ARTIFICIAL ORGANS, Issue 8 2009
Lieke G.E. Cox
Abstract Continuous flow ventricular assist devices (VADs) for mechanical circulatory support (MCS) are generally smaller and believed to be more reliable than pulsatile VADs. However, regarding continuous flow, there are concerns about the decreased pulsatility and ventricular unloading. Moreover, pulsatile VADs offer a wider range in control strategies. For this reason, we used a computer model to evaluate whether pulsatile operation of a continuous flow VAD would be more beneficial than the standard constant pump speed. The computer model describes the left and right ventricle with one-fiber heart contraction models, and the systemic, pulmonary, and coronary circulation with lumped parameter hemodynamical models, while the heart rate is regulated with a baroreflex model. With this computer model, both normal and heart failure hemodynamics were simulated. A HeartMate II left ventricular assist device model was connected to this model, and both constant speed and pulsatile support were simulated. Pulsatile support did not solve the decreased pulsatility issue, but it did improve perfusion (cardiac index and coronary flow) and unloading (stroke work and heart rate) compared with constant speed. Also, pulsatile support would be beneficial for developing control strategies, as it offers more options to adjust assist device settings to the patient's needs. Because the mathematical model used in this study can simulate different assist device settings, it can play a valuable role in developing mechanical circulatory support control strategies. [source]

Numerical Simulation of Hemodynamic Changes During Beating-heart Surgery: Analysis of the Effects of Cardiac Position Alteration in an Animal Model

ARTIFICIAL ORGANS, Issue 1 2007
Gianfranco Ferrari
Abstract:, Hemodynamic instability, mostly due to vertical lifting of the heart, is usually observed during beating-heart surgical procedures. However, some hemodynamic parameters, such as coronary blood flow, are not routinely measured. A digital computer model of the circulation able to simulate and analyze the effects of heart lifting and the Trendelenburg maneuver, and thus supply detailed hemodynamic information to the clinicians would provide a useful analytical tool. A lumped parameters model of the circulation was applied to both ,-blocked and not ,-blocked pigs. The results confirmed a drop of cardiac output and coronary flow during heart lifting and a rise of both variables after the Trendelenburg maneuver for ,-blocked animals. In not ,-blocked pigs, the analysis was more complex but the model reproduced experimental data and permitted coronary flow to be estimated. These results showed the feasibility of numerical simulation for specific circulatory conditions encountered during beating-heart surgery. [source]

Combined blockade of endothelin-1 and thromboxane A2 receptors against postischaemic contractile dysfunction in rat hearts

BRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2001
Pius S Hornstein
Endothelin-1 (ET-1) may play a role in myocardial ischaemia/reperfusion injury because both the release and vasoconstrictor effect of ET-1 are increased after ischaemia. Since the increased vasoconstrictor effect of ET-1 can be mediated by ET-1-induced release of thromboxane A2 (TXA2), the aim of this study was to test whether combined blockade of ET and TXA2 receptors protects the coronary flow, contractile performance, and cardiac energy metabolism during ischaemia and reperfusion. Bosentan (antagonist for ETA and ETB receptors, 1 ,M based on concentration-response curves of ET-1), SQ 30,741 (antagonist of TXA2 receptors, 0.1 ,M), or the combination thereof was administered to isolated perfused rat hearts undergoing 15 min of global ischaemia and 60 min of reperfusion. Neither bosentan or SQ 30,741 alone, nor the combination thereof, improved the incomplete postischaemic recovery of coronary flow, left ventricular developed pressure, phosphocreatine, or ATP. However, they attenuated ischaemia-induced acidosis but this did not translate into a measurable effect on haemodynamic or metabolic variables. Thus, combined blockade of ET and TXA2 receptors does not protect the coronary flow, contractile performance, and cardiac energy metabolism during ischaemia and reperfusion in isolated perfused rat hearts. This finding suggests that neither ET-1 nor ET-1-induced release of TXA2 play a major role in the postischaemic recovery of the cardiac contractile function and energy metabolism. British Journal of Pharmacology (2001) 132, 234,240; doi:10.1038/sj.bjp.0703773 [source]

Coronary no-reflow phenomenon: From the experimental laboratory to the cardiac catheterization laboratory,

CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 7 2008
Shereif H. Rezkalla MD
Abstract Coronary no-reflow occurs commonly during acute percutaneous coronary intervention, particularly in patients with acute myocardial infarction and those with degenerated vein grafts. It is associated with a guarded prognosis, and thus needs to be recognized and treated promptly. The pathophysiology originates during the ischemic phase and is characterized by localized and diffuse capillary swelling and arteriolar endothelial dysfunction. In addition, leukocytes become activated and are attracted to the lumen of the capillaries, exhibit diapedesis and may contribute to cellular and intracellular edema and clogging of vessels. At the moment of perfusion, the sudden rush of leukocytes and distal atheroemboli further contributes to impaired tissue perfusion. Shortening the door-to-balloon time, use of glycoprotein IIb/IIIa platelet receptor inhibitors and distal protection devices are predicted to limit the development of no-reflow during percutaneous interventions. Distal intracoronary injection of verapamil, nicardipine, adenosine, and nitroprusside may improve coronary flow in the majority of patients. Hemodynamic support of the patient may be needed in some cases until coronary flow improves. © 2008 Wiley-Liss, Inc. [source]

Effects of left ventricular unloading by Impella recover LP2.5 on coronary hemodynamics

CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 4 2007
Maurice Remmelink MD
Abstract Objectives: We studied the effects of LV unloading by the Impella on coronary hemodynamics by simultaneously measuring intracoronary pressure and flow and the derived parameters fractional flow reserve (FFR), coronary flow velocity reserve (CFVR), and coronary microvascular resistance (MR). Background: Patients with compromised left ventricular (LV) function undergoing high-risk percutaneous coronary intervention (PCI) may benefit from LV unloading. Limited information is available on the effects of LV unloading on coronary hemodynamics. Methods: Eleven patients (mean LV ejection fraction of 35 ± 11%) underwent PCI during LV support by the LV unloading device (Impella Recover® LP2.5). Intracoronary measurements were performed in a nonstenotic coronary artery after the PCI, before and after adenosine-induced hyperemia at four different support levels (0,2.5 L/min). Results: Aortic and coronary pressure increased with increasing support levels, whereas FFR remained unchanged. Baseline flow velocity remained unchanged, while hyperemic flow velocity and CFVR increased significantly with increasing support levels (61 ± 24 to 72 ± 27 cm/sec, P = 0.001 and 1.88 ± 0.52 to 2.34 ± 0.63, P < 0.001 respectively). The difference between baseline MR and hyperemic MR significantly increased with increasing support levels (1.28 ± 1.32 to 1.89 ± 1.43 mm Hg cm,1 sec, P = 0.005). Conclusions: Unloading of the LV by the Impella increased aortic and intracoronary pressure, hyperemic flow velocity and CFVR, and decreased MR. The Impella-induced increase in coronary flow, probably results from both an increased perfusion pressure and a decreased LV volume-related intramyocardial resistance. © 2007 Wiley-Liss, Inc. [source]

Laser-facilitated thrombectomy: A new therapeutic option for treatment of thrombus-laden coronary lesions

CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 3 2002
Johannes B. Dahm MD
Abstract To overcome the adverse complications of balloon angioplasty in thrombus burden lesions (i.e., distal embolization, platelet activation, no-reflow phenomenon with persistent myocardial hypoxemia), mechanical removal of the thrombus or distal embolization protection devices is required. Pulsed ultraviolet excimer laser light at 308 nm can vaporize thrombus and suppress platelet aggregation. Clinical experience has already shown its efficacy in acute ischemic-thrombotic acute coronary syndromes. Unlike other thrombectomy devices, a 308 nm excimer laser can ablate thrombi as well as the underlying plaque, speed up thrombus clearing, and enhance thrombolytic and GP IIb/IIIa activity. It can also be employed in patients with contraindications for systemic thrombolytic agents or GP IIb/IIIa antagonists. Our report covers clinical data and technical aspects concerning three patients with acute myocardial infarction who presented with a large thrombus burden. After successful laser-transmitted vaporization of the thrombus mass in these patients, the remaining thrombus burden was evacuated, and normal antegrade coronary flow was successfully restored. This approach can be useful for selective patients with acute coronary syndromes. Cathet Cardiovasc Intervent 2002;56:365,372. © 2002 Wiley-Liss, Inc. [source]

Acute effect of antidiabetic 1,4-dihydropyridine compound cerebrocrast on cardiac function and glucose metabolism in the isolated, perfused normal rat heart

CELL BIOCHEMISTRY AND FUNCTION, Issue 2 2008
Janina Briede
Abstract Diabetes mellitus (DM) is an important cardiovascular risk factor and is associated with abnormalities in endothelial and vascular smooth muscle cell function, evoked by chronic hyperglycemia and hyperlipidemia. Chronic insulin deficiency or resistance is marked by decreases in the intensity of glucose transport, glucose phosphorylation, and glucose oxidation, plus decreases in ATP levels in cardiac myocytes. It is important to search for new agents that promote glucose consumption in the heart and partially inhibit extensive fatty acid beta-oxidation observed in diabetic, ischemia. When the oxygen supply for myocardium is decreased, the heart accumulates potentially toxic intermediates of fatty acid beta-oxidation, that is, long-chain acylcarnitine and long-chain acyl-CoA metabolites. Exogenous glucose and heart glycogen become an important compensatory source of energy. Therefore we studied the effect of the antidiabetic 1,4-dihydropyridine compound cerebrocrast at concentrations from 10,10,M to 10,7,M on isolated rat hearts using the method of Langendorff, on physiological parameters and energy metabolism. Cerebrocrast at concentrations from 10,10,M to 10,7,M has a negative inotropic effect on the rat heart. It inhibits L -type Ca2+channels thereby diminishing the cellular Ca2+ supply, reducing contractile activity, and oxygen consumption, that normally favors enhanced glucose uptake, metabolism, and production of high-energy phosphates (ATP content) in myocardium. Cerebrocrast decreases heart rate and left ventricular (LV) systolic pressure; at concentrations of 10,10,M and 10,9,M it evokes short-term vasodilatation of coronary arteries. Increase of ATP content in the myocytes induced by cerebrocrast has a ubiquitous role. It can preserve the integrity of the cell plasma membranes, maintain normal cellular function, and inhibit release of lactate dehydrogenase (LDH) from cells that is associated with diabetes and heart ischemia. Administration of cerebrocrast together with insulin shows that both compounds only slightly enhance glucose uptake in myocardium, but significantly normalize the rate of contraction and relaxation (,±,dp/dt). The effect of insulin on coronary flow is more pronounced by administration of insulin together with cerebrocrast at a concentration of 10,7,M. Cerebrocrast may promote a shift of glucose consumption from aerobic to anerobic conditions (through the negative inotropic properties), and may be very significant in prevention of cardiac ischemic episodes. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Acute decrease of coronary flow after indomethacin delivery in newborn lambs

ACTA PAEDIATRICA, Issue 10 2007
Solweig Harling
Abstract Aim: To document the effects of indomethacin (IND) on coronary flow. Methods: We studied nine premature lambs during the first day of life. The gestational age varied between 132 and 134 days (term 145 days) and weight 3.1,4.7 kg. Coronary flow velocities were recorded with an intracoronary Doppler guide wire in the proximal left anterior descending coronary artery (LAD). Average peak flow velocity was measured before, during and after an intravenous IND injection of 0.2 mg per kilogram of body weight. Results: IND increased systemic blood pressure (p < 0.05) and rate pressure product (RPP; p < 0.05) indicating that IND increased cardiac workload. IND decreased coronary average peak flow velocity in all lambs (p < 0.05). The maximal fall in coronary velocity appeared after 3 min (range 1,7 min) and was regained 10 min (range 4,53 min) after the drug delivery. The maximal reduction of coronary average peak flow velocity was 52% (median 26). The recovery time was directly related to the maximal reduction of the coronary average peak flow velocity (R = 0.91, R2 0.84, p < 0.002). Conclusion: Coronary flow velocity decreased markedly in premature born lambs given a bolus dose of IND. [source]

Impaired Heart Function And Noradrenaline Release After Ischaemia In Stroke-Prone Spontaneously Hypertensive Rats

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 9 2000
Hong Chen
SUMMARY 1. Stroke-prone spontaneously hypertensive rats (SHRSP) are a strain of rat that exhibit severely high blood pressure and stroke attacks at an early age, but their heart function in vitro has seldom been studied in detail. Although the activity of the sympathetic nervous system is known to increase after myocardial ischaemia, there is little information about the cardiac release of noradrenaline (NA) associated with heart function after ischaemia in SHRSP. The aim of the present study was to examine heart function and cardiac NA release after ischaemia in SHRSP. 2. Isolated hearts of 4- and 8-month-old SHRSP and age-matched Wistar-Kyoto (WKY) rats were perfused in a working heart preparation and were subjected to 30 min ischaemia followed by 30 min reperfusion. Heart function and coronary flow were monitored throughout the experiment. Coronary effluent was collected for determination of NA using high- performance liquid chromatography coupled with electrochemical detection. 3. Under baseline conditions, cardiac output of 4-month-old SHRSP was slightly but significantly decreased compared with that of WKY rats (P < 0.05), although coronary flow was maintained normally at this age. Eight-month-old SHRSP showed a further impairment of systolic heart function, with lower coronary flow and higher coronary vascular resistance under baseline conditions. Elevated left ventricular end-diastolic pressure was evident in SHRSP at both ages before ischaemia. Heart function was severely damaged after 30 min global ischaemia in SHRSP from both age groups. Stroke-prone spontaneously hypertensive rats also showed lower coronary flow and higher coronary vascular resistance during reperfusion. 4. Coronary NA was not detectable in WKY rats or SHRSP at 4 months of age under baseline conditions. In 8-month-old SHRSP, pre-ischaemic NA release was significantly higher than that in age-matched WKY rat controls. The concentration of NA in the coronary effluent of SHRSP during reperfusion was also significantly higher than that of WKY rats at both ages. 5. These data demonstrate that SHRSP have early impairment of both systolic and diastolic heart function compared with WKY rats. Severe damage of heart function and coronary flow after ischaemia in SHRSP was accompanied with an increased release of NA, which may play a harmful role in heart function impairment in SHRSP after ischaemia. [source]

Effects Of The Na+/H+ Exchange Inhibitor Cariporide (HOE 642) On Cardiac Function And Cardiomyocyte Cell Death In Rat Ischaemic,Reperfused Heart

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2000
Hajime Otani
SUMMARY 1. Na+/H+ exchange has been implicated in the mechanism of reperfusion injury. We examined the effects of the cardiac-specific Na+/H+ exchange inhibitor cariporide (HOE 642) on postischaemic recovery of cardiac function and cardiomyocyte cell death (i.e. necrosis and apoptosis). 2. Rat isolated and buffer-perfused hearts were subjected to 25 min normothermic global ischaemia followed by 120 min reperfusion. Cariporide (10 ,mol/L) or its vehicle (0.01% dimethylsulphoxide) was administered for 15 min before ischaemia and for the first 30 min after reperfusion. 3. Cariporide significantly improved the recovery of isovolumic left ventricular function (heart rate, left ventricular developed pressure and left ventricular end-diastolic pressure) and coronary flow throughout reperfusion. Creatine kinase release during reperfusion was significantly less in the cariporide-treated heart. In situ terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL)- positive cardiomyocytes were also significantly less in the cariporide-treated heart after 120 min reperfusion. Electron microscopy showed necrotic changes without typical apoptotic features in cardiomyocytes after reperfusion. Such necrotic changes were mitigated by cariporide. Simultaneous detection of necrotic and apoptotic cardiomyocytes using propidium iodide (PI) and Annexin V revealed that cardiomyocytes in the infarct area were stained with only PI or both PI and Annexin V. Cariporide did not alter the pattern of cardiomyocyte staining with PI and Annexin V, although the number of cardiomyocytes stained with PI or PI plus Annexin V was less than that in vehicle-treated hearts. 4. These results suggest that apoptosis is not a major manifestation of cardiomyocyte cell death in the ischaemic, reperfused myocardium and a cariporide-sensitive mechanism of reperfusion injury promotes both necrotic and apoptotic processes of cell death. [source]

Transient global left ventricular dysfunction in a localized myocardial infarction related to occlusion of the distal left anterior descending artery

CLINICAL CARDIOLOGY, Issue 9 2006
Seong Bo Yoon M.D.
Abstract In some patients with acute myocardial infarction (MI), wall motion in the noninfarcted area declines globally despite localized myocardial damage. In most, an infarct-related lesion is the proximal part of the left anterior descending artery (LAD). Previous studies have reported that hypo-kinesis of remote myocardium may be related to multivessel disease, impaired coronary flow, or coronary flow reserve in nonculprit arteries. This report describes the case of a 53-year-old man who presented with severe global left ventricular (LV) dysfunction after an acute MI associated with distal LAD occlusion. Follow-up echocardiographic examination revealed nearly normalized LV function 5 days after the episode. We discuss a plausible mechanism of dysfunction of noninfarcted myocardium. [source]

Platelet function disorder in patients with coronary slow flow

CLINICAL CARDIOLOGY, Issue 3 2005
Dr. Mustafa Gökçe M.D.
Abstract Background: Some patients evaluated for chest pain with angiographically normal coronary arteries show coronary slow flow phenomenon (CSFP) on angiography. Slow flow of dye in epicardial coronary arteries is also not an infrequent finding in patients during routine coronary angiography. The precise pathophysiology of CSFP is not known yet. Hypothesis: This study investigates the presence of platelet function disorders in patients with CSFP. Methods: The patient group included 24 patients with CSFP detected by coronary angiography via the TIMI "frame count" method, and a control group included 23 patients with normal coronary flow. Platelet aggregability induced by use of ristocetin, collagen, and adenosine diphosphate (ADP), was measured from all blood samples in both control and patient groups. Results: The ratio of platelet aggregability increased significantly in patients with CSFP compared with patients with normal coronary flow (ristocetin 57.6 ± 15 vs. 45.4 ± 17.1, collagen 62.9 ± 16.4 vs. 48.9 ± 25.3, ADP 59.4 ± 18 vs. 42.4 ± 15.2, p < 0.05). Conclusion: Platelet aggregability is increased in patients with CSFP. [source]

Endothelial dysfunction, subangiographic atheroma, and unstable symptoms in patients with chest pain and normal coronary arteriograms

CLINICAL CARDIOLOGY, Issue 9 2000
Jonathan R. Clague M.D.
Abstract Background: Patients with chest pain and normal coronary arteriograms (CPNA) may present with unstable symptoms and other evidence of ischemia during clinical follow-up. Although repeat angiography usually proves negative, functional assessment of coronary vasomotor abnormalities may provide additional pathophysiologic information. Hypothesis: The study was undertaken to evaluate the relationship between endothelial dysfunction and subangiographic atheroma in patients with CPNA undergoing repeat angiography because of unstable symptoms. Methods: We investigated nine patients with CPNA (8 women, mean age 57 ± 9 years) undergoing repeat angiography because of unstable anginal symptoms. After normal angiography, simultaneous coronary epicardial and microvascular vasomotor responses to intracoronary vasodilators [acetylcholine (10,6 M), adenosine (18 ,g) and nitroglycerin (300 ,g)] were investigated in the left anterior descending artery using quantitative angiography and Doppler flow measurements. The presence of subangiographic atheroma was assessed by intravascular ultrasound. Results: Three patients demonstrated proximal and distal epicardial vasoconstriction and a reduction in coronary flow in response to acetylcholine, indicating concordant epicardial and microvascular endothelial dysfunction. These changes were associated with chest pain and ischemic electrocardio-graphic changes in two patients. None of the remaining patients suffered chest pain in response to intracoronary acetylcholine. Six patients had significant subangiographic disease (intimal thickness >0.3 mm) on intravascular ultrasound imaging, and multivariate analysis indicated a significant relationship (R2 = 0.89, overall p = 0.001) between the extent of subangiographic disease and both plasma cholesterol concentration and hypertensive history. No significant relationship was demonstrated between endothelial dysfunction and the extent of subangiographic disease. Conclusion: Concordant epicardial and microvascular endothelial dysfunction may be pathophysiologically and clinically significant in unstable patients with CPNA but does not appear to be directly related to the extent of subangiographic atheroma. [source]

Coronary arteries in fetal life: physiology, malformations and the "heart-sparing effect"

ACTA PAEDIATRICA, Issue 2004
R ChaouiArticle first published online: 2 JAN 200
The present knowledge of coronary arteries in prenatal diagnosis is reviewed with a focus on three aspects: the physiology and visualization of coronary flow, malformations involving the coronary arteries, and the "heart-sparing effect". Visualization of coronary arteries in a healthy human fetus is possible in real-time and colour Doppler during the last 10wk of gestation when ultrasound conditions are excellent. Visualization at an earlier gestational age (up to 13 wk) is feasible mainly in association with malformations and impending hypoxia. The main coronary malformations that can be visualized in utero are the ventriculo-coronary communications in fetuses with pulmonary atresia. In the last few years, interest has been focused on the "heart-sparing effect", defined as the increased perfusion of the coronary arteries in fetuses with severe growth restriction and abnormal Doppler velocimetry in the peripheral vessels. Increased perfusion detectable with colour and pulsed Doppler is a late sign of fetal compromise in hypoxaemia. It confirms animal experiments that have demonstrated dilatory reserves of the fetal coronary arteries under chronic hypoxaemia. The outcome of 21 fetuses showing the "heart-sparing effect" before 32 wk gestation was poor: nine fetuses died in utero and two after birth, the median weight at birth was 630 g. In summary, our knowledge of the coronary arteries in the fetus is based on the diagnostic means used in prenatal diagnosis. New information in this field may also contribute to a better understanding of coronary heart disease later in life. [source]