Left coronary artery inflow was recorded in the dog heart-lung preparation by means of a Gregg cannula and a Shipley-Wilson recording rotameter. Reactive hyperemia (RH) was induced by 10-second occlusions. The excess blood flow after release was quantified by planimetry and related to the "blood flow debt" incurred during the period of occlusion. In the normothermic heart, the excess coronary flow was 431% of the flow debt. At heart temperatures of 30 and 25.6° C, it dropped to 228% and 143% respectively. There was shortening of the duration of reactive hyperemia and reduction of peak flow at lower temperatures. These results were discussed in the light of chemical theories of the mechanism of reactive hyperemia and the effect of hypothermia thereon.. ...
Lipoprotein phospholipase A2 (Lp-PLA2) is an emerging inflammatory marker with prognostic value. Reactive hyperemia peripheral arterial tonometry (RH-PAT) is a method to assess peripheral microvascular endothelial function and is linked to coronary microvascular endothelial dysfunction. We investigated the association of Lp-PLA2 with RH-PAT, coronary flow reserve (CFR), and carotid intimal media thickness in CAD patients. Methods: Using RH-PAT, digital pulse volume changes during reactive hyperemia were assessed in 43 patients with angiographically documented CAD. RH-PAT index, a measure of reactive hyperemia, was calculated as the ratio of the digital pulse volume during reactive hyperemia divided by that at baseline using the Endo-PAT apparatus. Coronary flow reserve (CFR) of the LAD after adenosine infusion was assessed using Doppler echocardiography.The mean intima-media thickness (IMT) in common carotids and carotid bulbs using ultrasound imaging was also measured According to the values of ...
Introduction: Drug-eluting stents (DESs) are replacing bare-metal stents (BMSs), but in-stent restenosis (ISR) remains a problem. Impaired endothelial function is a key event in the atherosclerosis process and a predictor of future cardiovascular events. Reactive hyperemia index (RHI) assessed by peripheral arterial tonometry (PAT) evaluates endothelial function noninvasively.. Hypothesis: We prospectively assessed the prognostic value of RHI in predicting ISR after percutaneous coronary intervention (PCI).. Methods: RHI was measured using Endo-PAT 2000 before PCI (initial RHI) and at follow-up angiography (F/U RHI) in 249 consecutive patients who had successful PCI. F/U angiography was performed at six and nine months after PCI with BMS and DES, respectively. ISR was defined as percent diameter stenosis ,50% at F/U angiography assessed by quantitative coronary angiography.. Results: At F/U, ISR was seen in 68 patients (27.3%). F/U ln(RHI) was significantly lower in patients with ISR than in ...
OBJECTIVE: To investigate the effects of short term atorvastatin treatment on forearm vasodilatory response to reactive hyperaemia (RH%) and on components of the thrombosis-fibrinolysis system (antithrombin III, proteins and S, factors V and VII, von Willebrand factor, tissue plasminogen activator (tPA), and plasminogen activator inhibitor (PAI-1)) in patients with heart failure. PATIENTS AND METHODS: 35 patients with heart failure were enrolled in this study; 17 patients received atorvastatin 10 mg/day and 18 patients received no statin for four weeks. Forearm blood flow (FBF) was measured by venous occlusion strain gauge plethysmography. RH% and forearm vasodilatory response to nitrate were defined as the percentage change of FBF from rest to the maximum flow during reactive hyperaemia and after nitrate administration, respectively. Plasma concentrations of antithrombin III, protein C, protein S, factor V, factor VII, von Willebrand factor, tPA, and PAI-1 were determined before and after treatment.
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Synonyms for constriction hyperemia in Free Thesaurus. Antonyms for constriction hyperemia. 1 synonym for hyperemia: hyperaemia. What are synonyms for constriction hyperemia?
In this prospective study, older age, more invasive (noncarotid) surgery, and lower hyperemic flow velocity in the brachial artery predicted cardiovascular events in a high risk group of patients with peripheral arterial disease referred for surgery. When hyperemic flow velocity, a measure of microvascular function, flow-mediated dilation, a measure of conduit artery function, and other risk factors were included in the same multivariable model, both measures of vascular function were significant predictors, although flow-mediated dilation was the stronger predictor of risk. These findings suggest that microvascular and conduit artery vasodilator function provide incremental information about cardiovascular risk, and that both may relate to the pathogenesis of cardiovascular events.. Reactive hyperemia is a fundamental homeostatic response of the vasculature that serves to accelerate oxygen delivery to tissues following a period of ischemia. Hyperemic blood flow peaks within a few seconds after ...
TY - JOUR. T1 - Contribution of Adenosine A2A and A2B Receptors to Ischemic Coronary Dilation. T2 - Role of KV and KATP Channels. AU - Berwick, Zachary C.. AU - Payne, Gregory A.. AU - Lynch, Brandon. AU - Dick, Gregory M.. AU - Sturek, Michael. AU - Tune, Johnathan D.. PY - 2010/11/1. Y1 - 2010/11/1. N2 - This study was designed to elucidate the contribution of adenosine A2A and A2B receptors to coronary reactive hyperemia and downstream K+ channels involved. Coronary blood flow was measured in open-chest anesthetized dogs. Adenosine dose-dependently increased coronary flow from 0.72 ± 0.1 to 2.6 ± 0.5 mL/minute/g under control conditions. Inhibition of A2A receptors with SCH58261 (1 μm) attenuated adenosine-induced dilation by ~50%, while combined administration with the A2B receptor antagonist alloxazine (3 μm) produced no additional effect. SCH58261 significantly reduced reactive hyperemia in response to a transient 15 second occlusion; debt/repayment ratio decreased from 343 ± 63 to ...
Post Occlusive Reactive Hyperaemia (PORH). The increase in microvascular blood flow following arterial occlusion post occlusion reactive hyperaemia (PORH) can be assessed using the non-invasive laser Doppler technique. Following release of the arterial occlusion there is a marked transient increase
Methods 116 consecutive patients clinically diagnosed with AMI received evaluation of vascular endothelial function using PAT technique within 72 h of admission, reactive hyperaemia index (RHI) was calculated. By the cut point of normal RHI (1.67) patients were divided into the normal endothelial function group (RHI ,=1.67) and the endothelial dysfunction group (RHI,1.67), follow-up of MACE was conducted in both groups during hospitalisation (median value 8.0 days) and after discharge from hospital (243.8±68.3 days). MACE included cardiac death, recurrent acute myocardial infarction, recurrent unstable angina during hospitalisation, ischaemic stroke, elective PCI or CABG, and hospitalisation due to cardiovascular causes.. ...
It remains controversial which of the two regulators, red blood cell velocity (RBC-V) or concentration (RBC-C), is a main contributor to increasing flow (RBC-F) during functional hyperemia in the rat hippocampus induced by ,i,N,/i,-methyl-D-aspartate (NMDA). To address this, we monitored these parameters simultaneously under NMDA-infusion via microdialysis in the hippocampus of urethane-anesthetized rats and found a greater elevation in RBC-V than in RBC-C. This suggests that an RBC-V-dependent increase in RBC-F occurs under NMDA-induced functional hyperemia in the hippocampus as well as in the cortex.,br,. ...
Endothelial and microvascular function are important elements of overall cardiovascular health. Dysfunction in either or both is predictive of future cardiovascular events, thus preventing or minimizing the degree of dysfunction is critical to constraining the risk of such events. Reactive hyperemia is a transient increase in blood flow that occurs following a period of ischemia (e.g. arterial occlusion) and is indicative of microvascular health. Regular physical exercise is critical as a preventive measure in maintaining the capacity for reactive hyperemia; however, consistent dedication to regular exercise regimens is difficult or impossible for some people. Recent evidence suggests that chronic passive heat therapy (CHT) may result in improvements to cardiovascular health similar to that of exercise. PURPOSE: To examine the effects of 8 weeks of CHT on forearm post-occlusive reactive hyperemia. METHODS: Five, young, healthy and able-bodied university students (21 ± 1 years) underwent hot water
It is widely accepted that the coronary flow reserve is lower in subendocardium than in subepicardium.7 When coronary perfusion pressure is reduced stepwise while keeping myocardial oxygen demand constant, autoregulation is maintained, and transmural flow remains almost constant. As the pressure is lowered further, subendocardial flow decreases first, and a decrease in subepicardial flow reserve follows.5 Why is the coronary flow reserve in subendocardium lower than in subepicardium? The one possible reason is the difference in the vasodilatory responses between two layers. However, the present study demonstrated that the percent diameter change at peak reactive hyperemic flow was greater in subendocardial arterioles than in subepicardial arterioles (see Fig 3⇑). Thus, the hypothesis that decreased subendocardial flow reserve may be due to decreased vascular reactivity was shown to be unfounded. If anything, the vascular responses increased, perhaps in an attempt to compensate for the imposed ...
TY - JOUR. T1 - Microvascular function. T2 - A potential link between salt sensitivity, insulin resistance and hypertension. AU - De Jongh, Renate T.. AU - Serné, Erik H.. AU - Ijzerman, Richard G.. AU - Stehouwer, Coen D.A.. PY - 2007/9/1. Y1 - 2007/9/1. N2 - OBJECTIVE: Generalized microvascular dysfunction may contribute to the development of salt sensitivity, insulin resistance and hypertension, and may thus link these cardiovascular risk factors. To test this hypothesis, we examined skin microvascular function, salt sensitivity, insulin sensitivity and blood pressure in 27 normotensive and 26 hypertensive individuals. METHODS: Capillary density was examined by videomicroscopy during venous congestion and postocclusive reactive hyperaemia. Endothelium-(in)dependent vasodilation was assessed by iontophoresis of acetylcholine and sodium nitroprusside and by laser Doppler flowmetry. Salt sensitivity was determined as the difference in mean arterial pressure (MAP) between a 1-week high-salt diet ...
In the present study, the novel KATP channel antagonist HMR 1402 did not alter the cardiac action potential under control conditions but significantly attenuated the shortening of the APD90 induced either by the KATP channel agonist rilmakalim or by hypoxia. In a similar manner, the same concentration of this drug that attenuated these reductions in APD90 did not inhibit the activation of pancreatic or coronary vascular KATP channels in vitro. In conscious dogs, HMR 1402 prevented ischemically induced ventricular fibrillation without altering the increases in mean coronary blood flow induced either by submaximal exercise or by the reactive hyperemic response to brief (15-s) coronary artery occlusions. These findings were in marked contrast to glibenclamide that provoked large reductions in coronary blood flow (Billman et al., 1993, 1998). Finally, HMR 1402, in contrast to glibenclamide (Billman et al., 1998), did not alter plasma insulin concentrations. When considered together, these data ...
TY - JOUR. T1 - Na+-induced intestinal interstitial hyperosmolality and vascular responses during absorptive hyperemia. AU - Bohlen, H.. PY - 1982. Y1 - 1982. N2 - The coupled active transport of Na+ with sugars and amino acids could cause intestinal villus interstitial hyperosmolarity, which contributes to absorptive hyperemia. However, for the villus hyperosmolarity to cause a major vascular response, a mild-to-moderate hyperosmolarity must occur in the vicinity of the major resistance vessels of the submucosa. Interstitial Na+ activity was measured throughout the small intestinal wall of rats with monensin ion-selective electrodes during glucose absorption. In the upper half of villi, the resting [Na+] was 201 ± 5 (SE) mM and increased to 267 ± 6 mM during luminal exposure to 25-300 mg/100 ml glucose. The submucosal resting [Na+] was 144 ± 1 mM and increased to 177 ± 3 mM during luminal glucose exposure. The time courses of Na+ appearance and submucosal arterial dilatation were almost ...
The regulation of CBF in response to neuronal metabolic demand is a dynamic and tightly regulated process. Given that neuronal metabolism relies almost exclusively on oxidative metabolism, all normal function, from control of motor activity to cognitive ability and memory acquisition, requires adequate delivery of oxygenated blood. The cellular and molecular mechanisms underlying this coupling of neuronal metabolism to CBF remain poorly understood. Metabolic regulation of CBF is thought to involve release of vasoactive metabolites in response to neuronal activity. Numerous studies over the past decade have implicated modulation of ion channels by several diverse stimuli as one of the principal transduction processes responsible for defining the activation state of cerebral arteriolar muscle and thereby adjusting blood flow to meet metabolic demand. Very recently, studies from a number of laboratories, including our own, have defined a predominant role for metabolites of AA in controlling ion ...
Maximal twitch contractions of fast muscles of the cat caused an increase in phosphate concentration in the venous plasma from them: this efflux was greater as the contraction frequency was increased.
The investigators enroll consecutive, stable high risk patients for cardiovascular events. The reactive hyperemia peripheral arterial tonometry index (RHI) was measured before coronary angiography and coronary lesions were assessed angiographically by SYNTAX Scoring system. The investigators all subjects and examined the occurrence of cardiovascular events (CV death, non-fatal myocardial infarction and ischemic stroke, unstable angina pectoris, hospitalization for HF, coronary revascularization, or non-fatal aortic and peripheral vascular disease ...
MUSIC] Our previous talk was about normal conditions, how it is structured and regulated in health. Now about disease. There are three major typical pathological processes in microcirculation system. These are hyperaemia, ischaemia, and stasis. And all of them can occur separately, or as mosaic elements within a structure of bigger, more complicated pathological processes. For example, hyperaemia and stasis are embedded, as elements, into the structure of inflammation. Or for example, in thrombosis of arteriolae, a person is going to have ischaemia. In thrombosis of venulae, a person is going to have venous hyperaemia, and so on. So three major, typical pathological processes. Hyperaemia, local increase of blood supply and/or blood content in organ or in portion of tissue. Ischemia, local decrease of blood supply and blood content in organ or tissue portion. Stasis, local stop of blood flow in vessels, obligatory and within vessels. Here you can see the principle drawing of normal circulation, ...
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The presence of an increased amount of blood in a body part or an organ leading to congestion or engorgement of blood vessels. Hyperemia can be due to increase of blood flow into the area (active or arterial), or due to obstruction of outflow of blood from the area (passive or venous ...
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Intercellular waves of calcium (Ca2+) are an important signalling mechanism in a wide variety of cells within the body, crucial for cellular coordination and control. In particular the Ca2+ concentration within smooth muscle cells (SMCs) lining the blood vessel walls controls the cell dilation and contraction and thus the vessel radius. The process of functional hyperaemia by which neuronal activity results in a localised response of increased blood ow via the dilation of SMCs is associated with multiple pathologies such as cortical spreading depression (CSD). This process can be modelled by a `neurovascular unit (NVU) containing a neuron, astrocyte, and the SMC and endothelial cell (EC) within the vessel wall. Our research consists of modelling the Ca2+ dynamics of a both a single SMC and two coupled SMCs (via an intercellular Ca2+ ux) mainly with the minimal nonspatial Goldbeter et al. (1990) cell model. This is compared with the more complex model of a SMC/EC `unit which also includes the ...
In young women, superimposing CPT on FMD resulted in 1) a significant dilation during occlusion and reduction in peak diameter (Fig. 3), 2) an alteration in the postocclusion SR profile (Fig. 5) and 3) an ∼20% decrease in normalized popliteal FMD, when data were calculated relative to occlusion (Fig. 6). When FMD was calculated relative to rest, normalized FMD was not significantly influenced by adrenergic stimulation in young women. By contrast, popliteal dilation estimated relative to rest or occlusion was not significantly blunted in older women after superimposition of CPT on FMD (Fig. 6). These findings underscore the importance of analyzing FMD with respect to both resting and occlusion diameters since changes in conduit artery diameter during occlusion occur through different mechanisms as those evoked by reactive hyperemia and may affect estimation and assessment of endothelium-dependent dilation. Additionally, the application of CPT on FMD in the popliteal artery in young women did ...
Selected genes are highlighted in orange, bookmarked genes are green. - Chemical increases gene, - Chemical decreases gene, - Chemical increases and decreases gene simultaneosly, No arrows - gene doesnt interact with the chemical. - Gene should be increased/decreased most of the time and the chemical does it. - Gene should be increased/decreased most of the time but the chemical does the opposite. ...
Endothelix is dedicated to bringing Endothelial Function monitoring to physicians offices and patients homes like blood pressure monitoring is today. In fact, Endothelixs VENDYS system combines both BP and EF monitoring in one easy-to-use, fully automated device. VENDYS uses thermosensors at the fingertips to measure vascular reactivity during a 5-minute arm-cuff occlusion induced reactive hyperemia. VENDYS is FDA-cleared and is available to purchase or rent. Request a live demo or a quote at www.endothelix.com or call 650-263-7636. ACC Exhibit Hall Booth Number 509. ...
Mr. Anderson above proposes that the pump mainly effects slow twitch oxidative fibers because of capilarization (no strength; just mass). Dr. Lowery suggests that not being able to get a pump is a sign of fatigue - this i think is important. BUT if we look at occlusion training (which reactive hyperemia seems to be a type), then the pump should also be affecting both fast and slow twitch fibers myofibral growth. Occlulusion, it seems, may indeed get fast twitch fibers involved more directly than without occlusion - thats a theory. Since we also see in low load occlusion training effects on strength: it goes up. SO is this kind of self-occlusion with self-selected low resistance weights to induce the effect having the same effect as a cuff? Could be - as per this review ...
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A woman with controlled HIV infection developed in late August 2016 a pruritic rash with fever and conjunctival hyperaemia after a trip to the French Caribbean islands. On day 3 after symptom onset, Zika virus RNA was detected in plasma, urine and vaginal samples with respective viral loads of 3.8, 6.1 and 5.3 log copies/mL. Notably, we demonstrated the presence of infectious Zika virus particles in the vaginal samples by isolation in cell culture.
Mini debate) FFR and IFR: Hyperaemia mimics exercise more closely and is still essential for accurate physiological stenosis assessment in 2015 ...
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The current study had some limitations. First, we did not clarify the detailed molecular mechanism of how retinal glial cells regulate RBF in response to flicker stimulation. Although we recently found possible involvement of the retinal NO derived from nNOS in flicker-induced hyperemia in the retina in anesthetized cats,26 the current findings that L-NPA further reduced flicker-induced hyperemia in the retina after LAA treatment may indicate that NO derived from nNOS in retinal neurons and retinal glial cells may be involved in the flicker-induced hyperemia in the retina. In addition, although it was suggested that one particular mechanism of neurovascular coupling in which glial cells release vasodilatory PGE2 and/or EETs as the arachidonic acid metabolites produced by cyclooxygenase (COX) is a principal and perhaps dominant mechanism mediating functional hyperemia in the retina,5 we did not examine the role of these molecules in flicker-induced hyperemia in the retina because there is no ...
TY - JOUR. T1 - Oxotremorine-induced cerebral hyperemia does not predict infarction volume in spontaneously hypertensive or stroke-prone rats. AU - Harukuni, Izumi. AU - Takahashi, Hiroshi. AU - Traystman, Richard J.. AU - Bhardwaj, Anish. AU - Kirsch, Jeffrey R.. PY - 2000. Y1 - 2000. N2 - Objectives: We tested the following hypotheses: a) spontaneously hypertensive stroke-prone rats (SHR-SP) have more brain injury than spontaneously hypertensive rats (SHR) and normotensive controls (Wistar-Kyoto rats [WKY]) when exposed to transient focal ischemia; b) infarction size is not correlated with baseline blood pressure; and c) infarction size is inversely related to the cerebral hyperemic response to oxotremorine, a muscarinic agonist that increases cerebral blood flow (CBF) by stimulating endothelial nitric oxide synthase. Design: In vivo study. Setting: Animal laboratory in a university teaching hospital. Subjects: Adult age-matched male WKY, SHR, and SHR-SP. Interventions: Rats were instrumented ...
TY - JOUR. T1 - Interaction of nitric oxide, 20-HETE, and EETs during functional hyperemia in whisker barrel cortex. AU - Liu, Xiaoguang. AU - Li, Chunyuan. AU - Falck, John R.. AU - Roman, Richard J.. AU - Harder, David R.. AU - Koehler, Raymond C. PY - 2008/8. Y1 - 2008/8. N2 - Nitric oxide (NO) modulates vasodilation in cerebral cortex during sensory activation. NO is known to inhibit the synthesis of 20-HETE, which has been implicated in arteriolar constriction during astrocyte activation in brain slices. We tested the hypothesis that the attenuated cerebral blood flow (CBF) response to whisker stimulation seen after NO synthase (NOS) inhibition requires 20-HETE synthesis and that the ability of an epoxyeicosatrienoic acids (EETs) antagonist to reduce the CBF response is blunted after NOS inhibition but restored with simultaneous blockade of 20-HETE synthesis. In anesthetized rats, the increase in CBF during whisker stimulation was attenuated after the blockade of neuronal NOS with ...
This thesis aims to evaluate the blood flow velocity in the Brachial artery during reactive hyperemia. Primarily to appraise the information it might contain regarding cardiovascular function and cardiovascular risk.. Ultrasonographic doppler measurements of the Brachial artery were made on the 1016 men and women aged 70 included in the prospective investigation of the vasculature in Uppsala seniors (PIVUS) study. Analysis of the blood flow velocity in the forearm was made in comparison to established methods of estimating endothelial function, clinical markers of cardiovascular risk, the Framingham risk score and global atherosclerosis determined by whole body magnetic resonance angiography.. Systolic blood flow velocity was positively related to cardiovascular risk whereas the diastolic velocity was inversely correlated. However, the systolic to diastolic blood flow velocity (SDFV) ratio was more closely associated with cardiovascular risk than its components apart.. Ultrasonographic markers ...
Physical exam was reported as normal, besides hyperemia (redness) and slight edema at the urethral meatus , which should be ... venous drainage, cavernous-venous incompetence, hyperemia (external urethral meatus), edema (external urethral meatus), diabetic .... ...
In the coronary circulation, angiography of coronary artery responses to vasoactive agents may be used to test for endothelial function, and venous occlusion plethysmography and ultrasonography are used to assess endothelial function of peripheral vessels in humans.[3]. A non-invasive method to measure endothelial dysfunction is % Flow-Mediated Dilation (FMD) as measured by Brachial Artery Ultrasound Imaging (BAUI).[6] Current measurements of endothelial function via FMD vary due to technical and physiological factors. Furthermore, a negative correlation between percent flow mediated dilation and baseline artery size is recognised as a fundamental scaling problem, leading to biased estimates of endothelial function.[7]. A non-invasive, FDA-approved device for measuring endothelial function that works by measuring Reactive Hyperemia Index (RHI) is Itamar Medicals EndoPAT™.[8][9] It has shown an 80% sensitivity and 86% specificity to diagnose coronary artery disease when compared against the ...
Recent studies have revealed that functional hyperemia is initiated in capillaries (14, 15) and that RBCs themselves can act as oxygen-sensing regulators to control capillary RBC velocity in response to local PO2 changes (15). However, the underlying mechanisms of how PO2 could modulate RBC velocity in capillaries are unknown. Experimental findings presented here implicate that deoxyHb-band 3 interactions in RBCs are the molecular switch that responds to local PO2 changes and controls RBC deformability and consequently RBC capillary velocity. Evidently, we showed that (i) while ex vivo capillary velocity and deformation of mRBC-WT and mRBC-subst 1-35 exhibited a linear relation with local PO2 changes, RBCs from transgenic mice that had enhanced or weakened deoxyHb-band 3 interactions showed capillary velocity and deformation independent of PO2. RBCs with enhanced deoxyHb-band 3 interactions showed higher capillary velocity and deformability compared to RBCs that had weakened deoxyHb-band 3 ...
BioMed Research International is a peer-reviewed, Open Access journal that publishes original research articles, review articles, and clinical studies covering a wide range of subjects in life sciences and medicine. The journal is divided into 55 subject areas.
Transient bilateral common carotid artery occlusion (tBCCAO), followed by reperfusion, is a model of transient global hypoperfusion. In the present …
Background: There is a growing interest in the application of non-invasive clinical tools allowing one to assess the endothelial function, preceding atherosclerosis. The precision in estimating of the artery Flow Mediated Vasodilation (FMD) using standard 10-12 MHz linear array probes does not exceed 0.2 mm, far beyond that required. Methods: We have introduced a wide-band, high frequency 25-30 MHz, Golay encoded wobbling type imaging to measure dilation of the radial artery instead of the brachial one. 18 young volunteers, and 4 volunteers with cardiac events history, were examined. In the second approach 20 MHz linear scanning combined with 20 MHz pulsed Doppler attached to the linear array was used. The radial artery FMD was normalized using shear rate at the radial artery wall. Results and Conclusions: For the "healthy" group, the FMD resulting from reactive hyperemia response was over 20%; while in the "atherosclerotic" group, the FMD was at least twice as small, not exceeding 10%. The ...
What is the central question of this study? Although heat stress is known to increase cardiovascular strain, no study, to date, had explored the potential impact of exercise-induced heat stress on vascular function. What is the main finding and its importance? We found that acute exercise tended to reduce flow-mediated dilatation (FMD), owing in part to reduced reactive hyperaemia/shear stimulus; thus, when FMD is normalized to shear no postexercise deficit exists. Exercise-induced heat stress increased reactive hyperaemia, shear rate, coupled with a sustained FMD postexercise, suggests that exercise-induced heat stress increases the amount of shear stimulus to elicit a similar response, indicating reduced vascular responsiveness, or reserve, which might increase cardiovascular susceptibility.
iFR remains a novel technology that offers an alternative to stenosis assessment using hyperemia. Classification match with fractional flow reserve, a hyperemic pressure-only index, is good but is not expected to be absolute because fractional flow reserve classification itself can differ when the index is close to its binary cutoff point (10,25). Studies such as the CLARIFY (Classification Accuracy of Pressure-Only Ratios Against Indices Using Flow Study) (7) and comparisons with positron emission tomography (26) have shown that it is possible in certain circumstances to reduce the iFR value with administration of vasodilator drugs. Previously this may have been considered a limitation of a baseline index; however, 5 recent studies (26-30) demonstrated that iFR has sufficient sensitivity to not differ in diagnostic ability compared with FFR or iFR with vasodilators such as adenosine. This challenges the need for maximal hyperemia during stenosis assessment.. This study should be interpreted as ...
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Adenosine is a key metabolite involved in metabolic hyperemia in many vascular beds including coronary circulation, cerebral circulation, and skeletal muscle circulation.1 The roles of adenosine in vasculature are most prominent during hypoxia, ischemia, and reactive hyperemia.1 One important action of adenosine is to induce endothelium-dependent vasorelaxation.1-4 It is previously shown that, at least in some arteries, such as skeletal muscle arteries, a rise in [Ca2+]i is required for the endothelium-dependent vasorelaxation in response to adenosine.3-5 In the present study, we explored the possible role of CNG channels in adenosine-induced Ca2+ influx in vascular endothelial cells. Our results show that the adenosine-induced Ca2+ influx was markedly reduced by CNG-specific inhibitors L-cis-diltiazem and LY-83583 in H5V cells and in the primary cultured BAECs. Whole cell patch clamp recorded an adenosine-induced current that was sensitive to L-cis-diltiazem in both cell types. Furthermore, a ...
Researchers concluded that: (1) the protective activity of L-arginine involves gastric hyperemia (blood flow increase) mediated by NO (nitric oxide) and a mild irritant effect due to enhanced generation of endogenous prostaglandins, and (2) the ulcer healing properties of L-arginine depend upon its hyperemic and angiogenic actions, possibly involving NO.. Brzozowski T, Konturek SJ, Sliwowski Z, Drozdowicz D, Zaczek M, Kedra D. Role of L-arginine, a substrate for nitric oxide-synthase, in gastroprotection and ulcer healing. J Gastroenterol. 1997 Aug;32(4):442-52. See also ...
Conjunctival hyperemia is the engorgement of the blood vessels (redness) of the clear membrane covering the white surface of the eye. Conjunctival hyperemia was evaluated 15 minutes post conjunctival allergen challenge (CAC) (8 hours post dose) on Day 1 for both eyes using a 9-point scale in half-unit increments where: 0=none to 4=Extremely severe. The score for each participant was the average of the score of both eyes ...
Now, some details about venous or passive hyperaemia. Passive hyperaemia or venous congestion is increased blood supply to an organ or tissue due to reduced blood outflow through the veins. In venous congestion, blood velocity always decreases, decelerates. The etiology of venous congestion is related either to mechanical obstruction of blood flow in the veins. It can be thrombi or emboli, or it is resulted from external compression of the veins by ligation, by tumor, sometimes by pregnant uterus, if we speak about veins or abdominal cavity in pregnant women. It can be also some adhesions prevailing from normal venous outflow. And, here, you can see an illustration of the situation of total venous congestion in many vascular areas. It can occur in heart failure because of increase of venous pressure due to disorder of pumping functions, and it may occur simultaneously in many vascular beds, for example, with right heart failure or cor pulmonale. It may be observed in the greater circulation ...