Collateral growth and coronary angiogenesis are chronic adaptations to myocardial ischemia. Collateralization helps to restore blood flow and as a result salvages myocardium in severely ischemic myocardial regions. Thus, good collateral development in patients with severe coronary artery disease (CAD) improves ventricular function and prognosis (1-3).. However, coronary collateral development is different among patients even with similar degrees of coronary artery stenosis. Several factors, such as diabetes mellitus (4) and duration of myocardial ischemic symptoms (5) have been reported to effect coronary collateral development. At the cellular level, inflammatory cells, especially monocytes have an important role in collateralization. In a series of experimental studies with animals, it has been shown that monocytes are important elements for development of collateral vessels (6-7). In a recent study, it has been demonstrated that increased circulating monocyte count is related to good ...

AbstractBackground:Well-developed coronary collateral circulation usually results in fewer infarct size, improved cardiac function, and fewer mortality. Traditional coronary risk factors (diabetes, hypertension, and smoking) have some effects on coronary collateral circulation. However, the associat

The possibility that variation in the extent of native collateral circulation is an important determinant of variation in ischemic injury when acute arterial occlusion occurs or disease becomes manifest has historically been overlooked or minimized-, with the exception of those who study or treat acute ischemic stroke7-14 (and references therein), some coronary investigators4-6,69 (and references therein), and among vascular surgeons who frequently encounter or perform arterial occlusions.70,71 This presumably extends, in part, from the small diameter typical of native collaterals in most healthy individuals that is beyond the resolution of digital angiography (,0.2 mm), from the misconception that such minute vessels cannot mediate significant flow in the acute setting until remodeling has occurred, and from the inability to experimentally change native collateral extent to test its importance. The latter restriction has begun to yield in recent studies in which collateral extent was found to ...

Since the first description of the coronary collateral circulation in 1958,15 extensive investigations have been performed to elucidate the mechanisms that stimulate coronary collateral growth. Buschmann and colleagues16 were able to show a significant increase in collateral formation after 7 weeks of intermittent external counterpulsation in 23 patients with stable CAD in comparison with an inactive control group. An increase of collateral blood flow was detected by Zbinden in a nonrandomized clinical trial in 40 patients10 following regular physical exercise, performed 3 times a week over 3 months. However, PCI of the diseased vessel was performed before exercise training was initiated, which eliminated any possible ischemic trigger of collateral formation.. The underlying mechanism for increasing collateral blood flow has been the center of considerable debate.17 There are 2 distinct mechanisms that can be activated in the presence of ischemia caused by a flow-limiting lesion in an epicardial ...

Collateral circulation affects the prognosis of patients with acute ischemic stroke (AIS) treated by thrombolysis. The present study performed a systematic assessment of the impact of the collateral circulation status on the outcomes of patients receiving thrombolysis treatment. Relevant full‑text articles from the Cochrane Library, Ovid, Medline, Embase and PubMed databases published from January 1, 2000 to November 1, 2016 were retrieved. The quality of the studies was assessed and data were extracted by 2 independent investigators. The random‑effects model was used to estimate the impact of good vs. poor collateral circulation, as well as baseline characteristics, on the outcome within the series presented as risk ratios. Subgroup analyses explored the potential factors that may interfere with the effects of the collateral circulation status on the outcome. A total of 29 studies comprising 4,053 patients were included in the present meta‑analysis. A good collateral circulation status ...

The assessment of adequate ulnar collateral supply to the hand is mandatory prior to the harvest of the radial artery as a conduit for coronary artery bypass grafting. However, there is currently no one test which is widely used in all centres. We report a new and objective method of assessing ulnar collateral supply to the hand prior to harvest of the radial artery. This technique involves assessing the presence of a hyperaemic flow response to occlusion of the radial artery using an intraoperative transit time flowmeter. We found this technique to be objective and reliable, and would advocate its use in patients with a positive Allens test ...

Coronary collateral circulation from the cardiac lumen was studied in 36 anesthetized, open-chest dogs with hearts beating in situ. The coronary arteries were cannulated and perfused from an isolated, nonradioactive blood source while 131I-labeled blood circulated through the cardiac lumen for 2 minutes. Ventricular fibrillation was then produced, and luminal blood samples and myocardial tissue samples were obtained for radioactive assay and calculation of the amount of luminal blood appearing as a part of the myocardial blood volume. These volumes were obtained from both ventricles and the atria under (1) normal antegrade coronary flow conditions, (2) myocardial ischemia, (3) left and right ventricular hypertension, and (4) coronary occlusion. Small quantities of luminal blood appeared in the left ventricular myocardium under normal coronary flow conditions while considerably larger amounts were found in the right ventricle and atria. There was no significant increase of the luminal ...

Besides severity of coronary obstruction [37, 38], numerous factors that could possibly attenuate the development and biological function of coronary collaterals have been reported such as old age [39], traditional risk factors for coronary artery disease [40-44], hyperlipoprotein (a) [45], hyperuricemia [46] and elevated serum levels of CRP [47], TNF-a [48], N-terminal pro-brain natriuretic peptide [38] and mimecan [49], and high neutrophil/lymphocyte ratio [50]. In contrast, higher plasma levels of MCP-1 [51] or apelin [52] were associated with better coronary collateral development. The presence and extent of spontaneously visible coronary collaterals was also affected by plasma chemokine concentrations, as higher collateralization was associated with increased concentration of the angiogenic ligand and decreased concentrations of angiostatic ligands, and interferon-c [53]. It is known that diabetes mellitus aggressively induces atherosclerosis and may be more susceptible to myocardial ...

TY - JOUR. T1 - Impaired leptomeningeal collateral flow contributes to the poor outcome following experimental stroke in the type 2 diabetic mice. AU - Akamatsu, Yosuke. AU - Nishijima, Yasuo. AU - Lee, Chih Cheng. AU - Yang, Shih Yen. AU - Shi, Lei. AU - An, Lin. AU - Wang, Ruikang K.. AU - Tominaga, Teiji. AU - Liu, Jialing. PY - 2015/1/1. Y1 - 2015/1/1. N2 - Collateral status is an independent predictor of stroke outcome. However, the spatiotemporal manner in which collateral flow maintains cerebral perfusion during cerebral ischemia is poorly understood. Diabetes exacerbates ischemic brain damage, although the impact of diabetes on collateral dynamics remains to be established. Using Doppler optical coherent tomography, a robust recruitment of leptomeningeal collateral flow was detected immediately after middle cerebral artery (MCA) occlusion in C57BL/6 mice, and it continued to grow over the course of 1 week. In contrast, an impairment of collateral recruitment was evident in the Type 2 ...

Coronary heart disease (CHD) is a major health concern for Americans and people worldwide. Arteriogenesis, an adaptive remodeling process in which pre-existing collateral arterioles remodel to form large diameter conductance arteries, has received recent attention for its therapeutic potential in treating CHD, but the mechanisms regulating the process remain incompletely understood. In particular, little is known about how collateral flow, and the resulting effect of shear stress acting along the collateral vessel wall, regulates coronary collateralization. This Thesis combines a series of experimental systems to define the responses evoked in endothelial cells exposed to hemodynamic waveforms characteristic of coronary collateral vessels and the subsequent paracrine effects on smooth muscle cells. Initially, a lumped parameter model of the human coronary collateral circulation was used to simulate normal (NCC) and adaptive remodeling (ACC) coronary collateral shear stress waveforms. These ...

Further analysis of the IMS-III cohort of patients show that collateral status influence outcomes and those with intermediate collaterals seem to benefit the most from endovascular therapy. With the ESCAPE trial, collateral status was used as an inclusion criteria (patients with poor collaterals being excluded from the trial) and outcomes improved significantly in the endovascular group vs the IV tPA group. MR-CLEAN which was a study that did not use collateral status as an inclusion criteria did not have as significant overall good outcomes as the other published endovascular trials. Possibly because they included patients with poor collaterals, who dont benefit from either endovascular or IV tPA treatments as the infarct grows too rapidly for recanalization to have an effect. Had IMS-III recruited patients based on collateral status as in ESCAPE, we may have had a positive trial three years earlier. As we continue to understand the pathophysiological reasons for the success of the recent ...

Coronary artery disease (CAD) is the leading cause of death in industrialized countries. Current therapies for restoration of coronary flow are percutaneous coronary intervention (PCI) or surgical revascularization. However, inherent to them are procedure-related risks and the fact that CAD progression is not prevented. Additionally, up to one fourth of all CAD patients are not amenable to standard revascularization therapies. Thus, there is a need for alternative therapies. Coronary collaterals as natural bypasses are anastomoses without an intervening capillary bed between portions of the same coronary artery or between different coronary arteries. The coronary collateral circulation is prevalent in humans and in CAD the amount of collateral flow is directly related to infarct size, all-cause- and cardiac mortality. Thus, the goal is to promote collateral function in the sense of prophylactic myocardial salvage.. Coronary (collateral) blood flow occurs almost entirely during diastole. Fluid ...

Coronary collateral circulation plays an important role to protect myocardium from ischemia, preserve myocardial contractility and reduce cardiovascular events. Chronic kidney disease (CKD) is associated with poor coronary collateral development and

Previous clinical studies showed that the coronary wedge pressure is increased in the presence of collateral vessels, presumably as a consequence of a reduced collateral vascular resistance, resulting in a reduction of signs of ischemia during brief coronary occlusion ([3, 4, 6]). Our current understanding of the collateral circulation is limited, partly due to the lack of methods capable of expressing the development of the collateral vascular bed in terms of flow and resistance. The dynamic behavior of collateral vessels as seen angiographically before and during balloon coronary occlusion can be examined by blood flow velocity analysis in the contralateral donor coronary artery ([6, 7]). These studies demonstrated that a balloon coronary occlusion results in a transient 10% to 70% increase in coronary blood flow velocity in the contralateral artery when collateral vessels are present, although this phenomenon is marked in the absence of collateral vessels. Blood flow velocity changes in the ...

Conventional methods for qualitatively assessing human coronary collaterals include postmortem coronary angiography (5), patients history of a walking-through angina pectoris (30), nuclear cardiology techniques (31), recording of IC and surface ECG (19)and coronary wedge pressure (32)during PTCA and angiographic grading during vessel patency or occlusion (9). Positron emission tomography has been demonstrated to provide quantitative data of collateral flow to a vascular region of interest (31). However, this can be achieved only in the presence of a naturally occurring coronary artery occlusion of the ipsilateral vessel. The PTCA model for collateral assessment can be used in every patient with a stenotic lesion to be dilated. The presence of ECG ST-segment changes as a sign of myocardial ischemia is regarded to be quite sensitive in studies on collaterals (30). An ECG obtained during PTCA from an IC guidewire with its tip distal to the occluded stenosis can be used even more effectively. For ...

BACKGROUND AND PURPOSE: Current knowledge of the collateral circulation remains sparse, and a noninvasive method to better characterize the role of collaterals is desirable. The aim of our study was to investigate the presence and distal flow of collaterals by using a new MR perfusion territory imaging, vessel-encoded arterial spin-labeling (VE-ASL). MATERIALS AND METHODS: Fifty-six patients with internal carotid artery (ICA) or middle cerebral artery (MCA) stenosis were identified by sonography, VE-ASL was performed to assess the presence and function of collateral flow. The perfusion information was combined with VE maps into high signal-intensity-to-noise-ratio 3-colored maps of the left carotid, right carotid, and posterior circulation territories. The presence of the anterior and posterior collateral flow was demonstrated by the color of the standard anterior cerebral artery/MCA flow territory. The distal function of collateral flow was categorized as adequate (cerebral blood flow [CBF] >= ...

RESULTS: A total 269 patients were participated in the study population (55 in CIN(+) group, 214 in CIN(-) group). The blood creatinine levels were significantly higher in the CIN(+) group on the 48-72 hours following the coronary angiography. In the studied population, 70 out of 269 patients had a good CCC according the Rentrop classification (64 patients [30%] in the CIN(-) group, six patients [16%] in the CIN(+) group). The frequency of the well-developed coronary collaterals were significantly higher in the CIN(-) group ( ...

Background: We hypothesized that cerebral perfusion deficits are more severe in acute stroke patients with poor collaterals and that the severity would increase over time if reperfusion does not occur.. Methods: This is a substudy of DEFUSE 2. Collaterals were assessed on conventional angiography and dichotomized as poor vs. good flow. DWI and PWI were performed before and within 12 hrs after endovascular therapy; PWI lesion volumes were determined using a Tmax,6sec threshold. The hypoperfusion ratio (HR) was calculated by determining the proportion of the PWI lesion that had severe Tmax delay (,10sec). Acute lesion growth was defined as the difference between the baseline and follow-up DWI volume.. Part 1: In patients with an ICA or M1 occlusion we compared the HR to the collateral score. An ROC curve assessed whether the HR predicts the collateral score.. Part 2: Among patients who did not experience early reperfusion, the difference between the baseline and follow-up HR was assessed and ...

The extent of collateral circulation in 46 patients who had intracoronary thrombolysis within six hours of the onset of acute myocardial infarction was evaluated. Patients who had had a previous myocardial infarction (4 cases) or who had spontaneously recanalized infarct related coronary arteries (5 cases) were excluded from the analysis. Collateral development was graded during coronary cineangiography according to the extent of opacification of the collateral and epicardial arteries distal to the site of occlusion (collateral index 0 to 3). Angina was considered to be present before myocardial infarction if it had occurred more than one week before acute myocardial infarction. Collateral channels were visible in only two of 19 patients without angina before infarction and nine of the 18 patients with angina before infarction. The prevalence of angina and the collateral index were not significantly influenced by the extent of coronary vessel disease. It is concluded that myocardial ischaemia is ...

Rentrop et al. researched collateral filling of stenotic coronary artery during inflation of the PTA balloon. Contrast dye was injected as soon as the patient developed ST-T changes on ECG or angina, but no later than 90 seconds after inflation of the balloon.

The differences in the extent of collateral circulation among patients with seemingly similar clinical characteristics raise the possibility that genetic and molecular differences may play a role in collateral development. Because circulating monocytes are considered the key element in the development of collateral circulation, we set out to uncover novel transcriptional determinants of human coronary collateralization using a combination of established and newly developed microarray bioinformatics analysis techniques. The principal finding of this study is that the monocyte transcriptome of closely matched patients with CAD who possess abundant collateral circulation is significantly different from the transcriptome of collateral-poor CAD subjects. Interestingly, many of the observed changes in gene expression in this study parallel prior observations in a mouse model of hind-limb ischemia.37. The key differences include significant alterations in transcriptional regulation of specific ...

Background: Collateral grade on cerebral angiography has great predictive significance for patient outcome, which is important to determine indication for endovascular therapy in acute ischemic stroke (AIS). Distal hyperintense vessels (DHV) on fluid-attenuated inversion recovery imaging (FLAIR) is a noninvasive and useful imaging marker that reflects leptomeningeal collateral flow. We investigated whether DHV in patients with AIS was associated with collaterals grade on cerebral angiography and clinical outcome after endovascular therapy.. Methods: We retrospectively reviewed patients with AIS who had internal carotid artery or middle cerebral artery occlusion in three comprehensive stroke centers from August 2011 to July 2015. We selected those who underwent FLAIR sequence before endovascular therapy. Presence of DHV was evaluated using a previously-published method. Collateral grades on pre-treatment cerebral angiography were assessed with the American Society of Interventional and ...

Obesity is associated with impaired coronary collateral vessel development. Yilmaz, M.B.; Biyikoglu, S.F.; Akin, Y.; Guray, U.; Kisacik, H.L.; Korkmaz, S. // International Journal of Obesity & Related Metabolic Disorders;Dec2003, Vol. 27 Issue 12, p1541 BACKGROUND:: Chronic myocardial ischaemia due to coronary artery stenosis or occlusion has been shown to increase the growth of coronary collateral circulation. Collateralization leads to increased oxygen delivery to the area at risk and hence may reduce ischaemia, prevent infarction and... ...

We have demonstrated that in patients with AIS with terminal ICA or proximal MCA occlusions, the degree of collateral circulation on admission CTA correlates with the admission DWI lesion volume. Moreover, using a simple and reliable grading system, we have identified a malignant CTA collateral profile that is highly specific for patients with large baseline infarcts at high risk for poor long-term outcome. Our CTA collateral score of zero has ,95% specificity for admission DWI lesion volume ,100 mL and a ,90% rate of 3-month death or dependency. These findings are relevant for clinical practice because CTA is more widely available in the emergency setting than MR imaging-DWI. In addition, CTA collateral grading may provide a useful alternative for patients ineligible for MR imaging. Conventional angiography is the reference standard test for collateral evaluation because it incorporates the timing of collateral filling.16 However, its major drawbacks include its invasiveness and the time ...

Peripheral arterial disease (PAD) is a global problem - over 202 million people worldwide are estimated to have PAD. In the United States alone, PAD results in $21 billion in annual costs and is the leading cause of lower limb amputation. PAD arises when atherosclerotic plaques block arteries in the lower limbs, thereby limiting blood flow to the distal tissue. A promising therapeutic approach to restore distal blood flow is to stimulate the lumenal growth of the patients own pre-existing collateral arteries that bypass the occlusion(s) (i.e. arteriogenesis). Unfortunately, large clinical trials have had limited success to date, highlighting the critical need to better understand the basic mechanisms regulating arteriogenesis.. Arteriogenesis occurs in response to increased blood flow through the collateral arteries that bypass an occluded artery. We have recently demonstrated that arteriogenesis varies along collateral artery pathways due to differences in regional hemodynamics (Heuslein and ...

No. Wellens T-waves are always AFTER an episode of pain, and when no ECG was recorded DURING the pain. But we know from reperfusion trials that this is exactly the same kind of T-wave inversion we get after reperfusion. So, extrapolating backward in time, those who have Wellens had upright T-waves with ST elevation at the time of their pain. They had spontaneous reperfusion (which is very common in STEMI) and when the were pain free with open artery (or good collateral circulation), then the ECG was recorded and showed T-wave inversion. In Wellens study, all 180 patients had EITHER an open LAD or good collateral circulation to the anterior wall.. ReplyDelete ...

RESULTS: Factors associated with good outcome on univariable analysis were younger age, female sex, hypertension, diabetes mellitus, atrial fibrillation, small infarct core (ASPECTS ≥8), vessel recanalization, lower pre-tPA NIHSS scores, and good collaterals according to Tan methodology, ASPECTS methodology, and Miteff methodology. On multivariable logistic regression, only lower NIHSS scores (OR, 1.186 per point; 95% CI, 1.079-1.302; P = .001), recanalization (OR, 5.599; 95% CI, 1.560-20.010; P = .008), and good collaterals by the Miteff method (OR, 3.341; 95% CI, 1.203-5.099; P = .014) were independent predictors of good outcome. Poor collaterals by the Miteff system (OR, 2.592; 95% CI, 1.113-6.038; P = .027), Maas system (OR, 2.580; 95% CI, 1.075-6.187; P = .034), and ASPECTS method ≤5 points (OR, 2.685; 95% CI, 1.156-6.237; P = .022) were independent predictors of extremely poor outcomes. ...

The human coronary circulation is not an end-arterial system. Coronary collateral circulation has been shown to have a significant protective

Our ability to link amplified arteriogenesis to a unique hemodynamic stimulus (ie, reversed flow with increase shear stress magnitude) was facilitated by the development of a LSF approach for mouse hindlimb collaterals.18 We developed that approach because, despite the known importance of hemodynamic stimuli in driving collateral development, there was a surprising lack of quantitative data on the hemodynamic changes within these arteries. This is likely because both the small size of the arteries (,100 μm) and the fact that different surgical models elicit arteriogenesis along different collateral pathways.2 Using LSF,18 we determined the occurrence of at least 3 distinct hemodynamic conditions in these collateral vessels: a nonreversed increase in shear stress near the feeding entrance to the collateral loop, an increase in shear stress from low/oscillating flow to sustained high shear stress at the central anastomotic region, and an increase in shear stress but in a reversed direction at the ...

Clinical outcome after mechanical thrombectomy (MT) for large vessel occlusion (LVO) stroke is influenced by the intracerebral collateral status. We tested the hypothesis that patients with preexisting ipsilateral extracranial carotid artery stenosis (CAS) would have a better collateral status compared to non-CAS patients. Additionally, we evaluated MT-related adverse events and outcome for both groups.Over a 7-year period, we identified all consecutive anterior circulation MT patients (excluding extracranial carotid artery occlusion and dissection). Patients were grouped into those with CAS ≥ 50% according to the NASCET criteria and those without significant carotid stenosis (non-CAS). Collateral status was rated on pre-treatment CT- or MR-angiography according to the Tan Score. Furthermore, we assessed postinterventional infarct size, adverse events and functional outcome at 90 days.We studied 281 LVO stroke patients, comprising 46 (16.4%) with underlying CAS ≥ 50%. Compared to non-CAS ...

Methods and Results-We screened for signaling components that are activated in response to administration of FGF-2 to cultured vascular smooth muscle cells (VSMCs) and detected a significant increase of Rap2 but not of other Ras family members, which corresponded to a strong upregulation of Rap2 and C-Raf in growing collaterals from rabbits with femoral artery occlusion. Small interfering RNAs directed against Rap2 did not affect FGF-2 induced proliferation of VSMC but strongly inhibited their migration. Inhibition of FGF receptor-1 (FGFR1) signaling by infusion of a sulfonic acid polymer or infection with a dominant-negative FGFR1 adenovirus inhibited Rap2 upregulation and collateral vessel growth. Similarly, expression of dominant-negative Rap2 blocked arteriogenesis, whereas constitutive active Rap2 enhanced collateral vessel growth.. ...

Results and Discussion: Receiver Operating Characteristics demonstrated no improvement using frequency dependant impedance compared to the constant part of the collateral impedance. The functional parameters aCon and cIMP were better than the total blood flow for the characterization of collateral function. The collateral function improved significantly during occlusion time (aCON in one= 0.20+/-0.17, two=0.22+/-0.25, three and more month= 0.28+/-0.18 cm*s-1*mmHg-1). A predominant systolic, diastolic or combined collateral flow profile was not correlated to the collateral function. Considering the anatomic location of Levin 17 patients had one, 15 two and 24 three different collateral pathways. In the majority of cases (63 of 91 patients) a septal pathway was included. In all patients the comparison of the Rentrop grading, the anatomic location classification and the collateral connection grading showed only for the latter an independent and significant relation with the collateral function. In ...

Collateral blood flow plays a pivotal role in steno-occlusive internal carotid artery (ICA) disease to prevent irreversible ischaemic damage. Our aim was to investigate the effect of carotid artery disease upon cerebral perfusion and cerebrovascular reactivity and whether haemodynamic impairment is influenced at brain tissue level by the existence of primary and/or secondary collateral. Eighty-eight patients with steno-occlusive ICA disease and 29 healthy controls underwent MR examination. The presence of collaterals was determined with time-of-flight, two-dimensional phase contrast MRA and territorial arterial spin labeling (ASL) imaging. Cerebral blood flow and cerebrovascular reactivity were assessed with ASL before and after acetazolamide. Cerebral haemodynamics were normal in asymptomatic ICA stenosis patients, as opposed to patients with ICA occlusion, in whom the haemodynamics in both hemispheres were compromised. Haemodynamic impairment in the affected brain region was always present in

We previously showed that prompt reperfusion and angiographic collateral vessels may impact myocardial salvage and infarct transmural extent among patients with an occluded IRA. In the current investigation, we found that in addition to time to reperfusion and collateral vessels, the angiographic area at risk and the initial TIMI flow grade at the time of PCI are independent predictors of myocardial salvage by multivariate analysis. The novel index of myocardial salvage described here compares favorably with infarct transmurality to predict wall motion recovery after an acute STEMI.. Previous experimental studies have shown that the final infarct size closely correlates with the mass of jeopardized myocardium within the territory of the IRA (9). It is known that reperfusion of an occluded artery results in greater improvement in regional LV function when collateral vessels are present in the acute phase of myocardial infarction (10). However, the adjunctive effect that collateral flow might have ...

CONTRAST-ENHANCED CARDIAC COMPUTED TOMOGRAPHY (CT) is being increasingly used for the investigation of patients with suspected coronary artery disease. Recent technological developments have allowed the reliable diagnosis of both coronary stenosis and occlusion with this modality. In addition to the identification of luminal stenosis, CT has the potential to visualize coronary plaque, collateral circulation, myocardium, and left ventricular function. Although the typical CT appearance of chronic coronary occlusion (extensive calcification and negative remodeling within the artery, potential presence of collateral coronary circulation and, in most cases, impaired left ventricular function associated with thinned myocardium) is well known, characteristics of acute occlusion have not been well described. The distinction between acute and chronic coronary occlusion has particular importance for the management of patients presenting with acute chest pain. In this series of cases, we highlight some ...

OBJECTIVES. The aim of this study was to evaluate myocardial blood flow regulation in collateral-dependent myocardium of patients with coronary artery disease. BACKGROUND. Despite great clinical relevance, perfusion correlates of collateral circulation in humans have rarely been estimated by quantitative methods at rest and during stress. METHODS. Nineteen patients with angina and isolated occlusion of the left anterior descending (n = 14) or left circumflex (n = 5) coronary artery were evaluated. Using positron emission tomography and nitrogen-13 ammonia, we obtained flow measurements at baseline, during atrial pacing-induced tachycardia and after intravenous administration of dipyridamole (0.56 mg/kg body weight over 4 min). Flow values in collateral-dependent and remote areas were compared with values in 13 normal subjects. RESULTS. Flow at rest was similar in collateralized and remote myocardium (0.61 +/- 0.11 vs. 0.63 +/- 0.17 ml/min per g, mean +/- 1 SD), and both values were lower than ...

INTRODUCTION Stimulation of coronary collateral vessel growth by therapeutic angiogenesis (TA) offers an alternative treatment option for patients with refractory angina. Several TA modalities, including delivery to the heart of angiogenic growth factors (proteins or genes) and cells have been tested in clinical trials in the past two decades, but so far none of them resulted in significant therapeutic efficacy in large scale studies. This review attempts to identify the main obstacles hindering clinical success and recommends measures to overcome them in the future. AREAS COVERED After stating the medical need and rational for TA, and listing and briefly discussing past and current TA clinical trials, three main areas of obstacles are described: conceptual questions, technical limitations and clinical design uncertainties. Based on scientific and technical advances and lessons learned in past clinical trials, potential solutions to overcome some of these obstacles are proposed. EXPERT OPINION

A collateralized debt obligation is an investment that is backed by a collection of several different assets. While collateralized...

In stroke due to middle cerebral artery (MCA) occlusion, collaterals may sustain tissue in the peripheral MCA territory, extending the time window for recanalizing therapies. However, MCA occlusions often block some or all of the lenticulostriate (LS) arteries originating from the M1 segment, eliminating blood flow to dependent territories in the striatum, which have no collateral supply. This study examines whether mechanical thrombectomy (MTE) can avert imminent striatal infarction in patients with acute MCA occlusion.279 patients with isolated MCA occlusion subjected to MTE were included. Actual LS occlusions and infarctions were assigned to predefined LS occlusion and LS infarct patterns derived from known LS vascular anatomy. The predictive performance of LS occlusion patterns regarding ensuing infarction in striatal subterritories was assessed by standard statistical measures.LS occlusion patterns predicted infarction in associated striatal subterritories with a positive predictive ...

OBJECTIVE: Elevated mean platelet volume (MPV) has been proposed as a risk factor for coronary artery disease (CAD) and is associated with poor clinical outcome in acute coronary syndrome (ACS). We aimed to evaluate the association of MPV with presence of coronary collateral vessel (CCV) in patients with ACS.. METHODS: A total of 417 patients with ACS were included in the study. All patients underwent coronary angiography on the first day after admission and patients with a greater than or equal to 80% obstruction in at least one epicardial coronary artery were included in the study. The CCVs are graded according to the Rentrop scoring system and a Rentrop grade 0 was accepted as no CCV development (group 1), Rentrop grade 1-2-3 were accepted as presence of CCV development (group 2).. RESULTS: The median of MPV was 9.1±1.4fl. Mean age was 60±12 year. Group 1 consisted of 233 (55.9%) patients and Group 2 consisted of 184 (44.1%) patients. Presence of CCV was significantly associated with high ...

BACKGROUND AND PURPOSE: Blood supply through collateral pathways improves regional cerebral blood flow and may protect against ischemic events. The effect of collaterals on the risk of stroke and transient ischemic attack (TIA), in the presence of angiographic severe internal carotid artery (ICA) stenosis, was assessed. METHODS: Angiographic collateral filling through anterior communicating and posterior communicating arteries and retrograde filling through ophthalmic arteries were determined in all patients at entry into the North American Symptomatic Carotid Endarterectomy Trial. Kaplan-Meier event-free survival analyses were performed on 339 medically treated and 342 surgically treated patients. RESULTS: The presence of collaterals supplying the symptomatic ICA increased with severity of stenosis. Two-year risk of hemispheric stroke in medically treated patients with severe ICA stenosis was reduced in the presence of collaterals: 27.8% to 11.3% (P=0.005). Similar reductions were observed for

Aneurysm surgery: optic nerve often displaced superiorly by aneurysm, vs. falciform ligament (sharp tethering edge). Early opening of optic canal & falciform ligament to free optic nerve --, decrease risk of visual deficit. If clipped, orbit dependent on collateral supply from ECA (maxillary, facial arteries ...

This report studies the Global Collateralized Debt Obligation Market, analyzes and researches the Collateralized Debt Obligation development status and...

Decreased collateral vessel formation in the diabetic peripheral limbs is characterised by abnormalities of the angiogenic response to ischemia. Hyperglycemia is known to activate protein kinase C (PKC) affecting the expression and activity of growth factors such as VEGF and PDGF. The present study investigates the role of PKCδ in diabetes-induced poor collateral vessel formation and inhibition of angiogenic factors expression and actions. Ischemic adductors muscles of diabetic Prkcd+/+ mice exhibited reduced blood reperfusion, vascular density and number of small vessels as compared to non-diabetic Prkcd+/+ mice. By contrast, diabetic Prkcd-/- mice showed significant increased blood flow, capillary density and number of capillaries. Although expression of various PKC isoforms were unchanged, activation of PKCδ was increased in diabetic Prkcd+/+ mice. VEGF and PDGF mRNA and protein expression were decreased in muscles of diabetic Prkcd+/+ mice and normalized in diabetic Prkcd-/- mice. ...

There is intense controversy as to the mechanisms underlying chronic but reversible left ventricular (LV) ischemic dysfunction. The aim of this study was to investigate the physiology underlying this condition in a canine model of noninfarcted collateral-dependent myocardium. METHODS: Six mongrel dogs were instrumented with ameroid constrictors on the left circumflex and right coronary arteries and a partial occluder on the left anterior descending coronary artery. The animals were followed up for 6 mo. Every 6 wk, measurements of regional wall thickening (M-mode echo), myocardial blood flow ((13)N-ammonia PET), oxygen consumption ((11)C-acetate PET), and glucose uptake ((18)F-FDG PET) were obtained. After 6 mo, myocardial blood flow reserve (during adenosine infusion) and regional contractile reserve (during infusion of a low dose of dobutamine) were also investigated. RESULTS: Following ameroid implantation, regional thickening decreased in the posterior wall (to 34% +/- 13% of baseline; P , ...

Natural adaptation to femoral artery occlusion in animals by collateral artery growth restores only approximately 35% of adenosine-recruitable maximal conductance (C(max)) probably because initially elevated fluid shear stress (FSS) quickly normalize

You need to be signed in to access email alerts. If you have an account log in with your user name and password. If you dont have an account you can just enter your email address in the email box below ...

If patients could recognise themselves, or anyone else could recognise a patient from your description, please obtain the patients written consent to publication and send them to the editorial office before submitting your response [Patient consent forms] ...

Looking for online definition of collateral bundle in the Medical Dictionary? collateral bundle explanation free. What is collateral bundle? Meaning of collateral bundle medical term. What does collateral bundle mean?

Looking for online definition of Collateral estoppel in the Medical Dictionary? Collateral estoppel explanation free. What is Collateral estoppel? Meaning of Collateral estoppel medical term. What does Collateral estoppel mean?

Many collateral adjectives enter the language because English regularly substitutes attributive use of the noun itself (or of a verbal noun from a related verb) for use of an adjective, so true adjectives are often missing. Adjectives are then borrowed from Greek or Latin for technical and academic usage, where true adjectives are preferred over attributive use of nouns. Because of this, collateral adjectives tend to be more technical or academic in tone than their corresponding nouns. Some collateral adjectives have a related noun which may be a near synonym for the noun in question. For example, one adjective for business is commercial, which also has a cognate noun commerce. Because there is no one-to-one correspondence between adjective and noun in English, and there is no regular derivation that they upset, they are not actually suppletive. Some nouns have both collateral and derived adjectives. For example, for the noun father there is derived fatherly alongside collateral paternal, and ...

This CLE course will provide counsel with an understanding of the scope and application of Section 506(c) allowing the debtor or trustee to recover from the secured lender costs and expenses of preserving/disposing of the estates asset. The panel will explain surcharge on collateral, the debtors burden under 506(c) and recent case law, and outline best practices for secured lenders to defeat a surcharge motion.

Toronto-based GDA Group, a North American digital assets firm specializing in capital advisory and trading services to institutional investors, announced the launch of GDA Lending. The new service will provide investors with access to non-recourse lending for USD, BTC, ETH, EOS and XRP at up to 65% loan-to-value ratio.. GDA Lending joins the ranks of other crypto lending institutions such as BlockFi, Nexo and DrawBridge Lending (recently acquired by Galaxy), which offer collateralized lending to its clients. Bitcoin golden physical coin illustration on Euro banknotes of 20 and 50 euros. visual … [+] representations of the digital Cryptocurrency Bitcoin with the Euro bill. Bitcoin is a popular digital currency that showed growth and is widely spread, accepted from banks, markets and other services and shops as ways of payments. The exchange rate today for 1 bitcoin blockchain is 9969 euros. Thessaloniki, Greece - August 8, 2020 (Photo by Nicolas Economou/NurPhoto via Getty ...

Hemorrhage: Trans-Arterial Embolization for Hemorrhage or Vascular Malformations. Veterinary patients occasionally suffer from hypovolemic shock secondary to severe hemorrhage from a number of different causes including neoplasia, coagulopathy, GI ulceration, and trauma. In the majority of cases, standard medical and surgical procedures can be used to stabilize these often severely debilitated animals. Occasionally, standard therapies fail and alternatives are necessary.. For example, severe epistaxis can typically be managed conservatively. However, once intractable, few options remain. Carotid ligation can be performed and although this may temporize bleeding, once collateral blood supply develops bleeding may resume and no further treatment options exist. This is an especially important consideration when the underlying cause of epistaxis persists because the patient remains at risk for bleeding. An alternative to carotid ligation that permits repeated treatments if necessary is ...

TY - JOUR. T1 - MR Perfusion to Determine the Status of Collaterals in Patients with Acute Ischemic Stroke. T2 - A Look Beyond Time Maps. AU - Nael, Kambiz. AU - Doshi, A.. AU - De Leacy, R.. AU - Puig, J.. AU - Castellanos, M.. AU - Bederson, J.. AU - Naidich, T. P.. AU - Mocco, J.. AU - Wintermark, M.. PY - 2018/2/1. Y1 - 2018/2/1. N2 - BACKGROUND AND PURPOSE: Patients with acute stroke with robust collateral flow have better clinical outcomes and may benefit from endovascular treatment throughout an extended time window. Using a multiparametric approach, we aimed to identify MR perfusion parameters that can represent the extent of collaterals, approximating DSA. MATERIALS AND METHODS: Patients with anterior circulation proximal arterial occlusion who had baseline MR perfusion and DSA were evaluated. The volume of arterial tissue delay (ATD) at thresholds of 2- 6 seconds (ATD2- 6seconds) and 6 seconds (ATD6seconds) in addition to corresponding values of normalized CBV and CBF was calculated ...

Arteriogenesis, the adaptive outward growth of pre-existing collateral arteries, is the most efficient endogenous rescue mechanisms in vertebrates against the occlusion of a major artery (biological bypass). Here, collateral growth was induced using the first model for cerebral arteriogenesis, the 3-vessel occlusion (3-VO) rat model. (I) 3-VO resulted in a significant diameter increase within 7 days in the posterior cerebral artery (PCA) and posterior communicating artery (Pcom), classifying the region of interest. Immunhistological staining demonstrated proliferative activation and macrophage invasion, already 24h post 3-VO within the PCA, confirming the arteriogenic phenotype. Furthermore, activation of the PCA endothelium was detected within 3 days post 3-VO by scanning electron microscopy. (II) For analysing the molecular mechanism of cerebral arteriogenesis, collateral tissue from the growing PCA was selectively isolated. Here, 24h post 3-VO 164 genes were detected to be significantly ...

Tim unlocks opportunities for wealth creation for Black, rural entrepreneurs by shifting our current economic development approach away from an overemphasis on collateral and prior wealth, and towards an appreciation of peer support and community prosperity.

Lee CW, Stabile E, Kinnaird T, Shou M, Devaney JM, Epstein SE, Burnett MS. Temporal patterns of gene expression after acute hindlimb ischemia in mice: insights into the genomic program for collateral vessel development. J Am Coll Cardiol. 2004 Feb 04; 43(3):474-82 ...

To date, regenerative laboratories have attempted to engineer only a few whole organs. This endeavor requires engineering not only the organ but also vascular tissues to maintain a healthy organ with full functionality. We concentrated our initial efforts on developing the microvasculature and systemic support in the BEL and found that collateral systemic circulation developed in all animals that survived 2 weeks or longer. Because BEL was supplied with oxygenated rather than deoxygenated blood, we were unable to assess gas exchange due to a lack of an oxygen gradient at the alveolar capillary junction.. GE related to angiogenesis and lung tissue development indicated that tissue development was still in progress 1 month after transplantation. Histological examination of tissues indicated that collateral circulation developed in all animals as early as 2 weeks after transplant. Histological evaluation showed progression in lung and airway epithelial cell development with an associated increase ...

A method of delivering an arteriogenic factor. The factor is delivered in a medically effective manner to structurally enlarge an existing blood vessel. A distal portion of a catheter can be advanced to an existing blood vessel to deliver the arteriogenic factor.

Collateral sprouting of axons in the pe-ripheral nervous system is a branching out-growth of new axon terminals from non-injured axons into adjacent denervated regions of tar-get tissue. The initiation of collateral sprouting is probably triggered by the interaction between the factors released by degenerated neural pathways or denervated target tissue, and pu-tative interaction between the injured and non-injured neurons within a dorsal root ganglion (transneuronal mechanism). Sprouting of axons along the neurilemmal tubes of Schwann cells was investigated by an end-to-side anastomo-sis of a peroneal nerve segment to the intact su-ral nerve on the hind limb of the rat. In group A, the peroneal nerve segment from the contrala-teral limb was attached to the sural nerve. No-ne of the nerves on the side of the anastomosis were injured. In group B, the same procedure was used as in group A. In addition, dorso-cutaneous nerves from the L4-L6 spinal segments were cut. Injured neurons were therefore ...

Formats for Collaterals: The formats, as per NSE Clearing, that are required for submission of documents for Trading Members operating in the Capital Market Segment. Know more about Formats for Collaterals Today, visit NSE India.

Unbound Finance operates a so-called liquidation-free collateralization platform, which, because the identify suggests, permits customers to acquire interest-free loans in opposition to collateralized tokens. Automated market makers are DeFis Zero to One Innovation and were constructing the aggregator layer to allow higher yields [and] capital effectivity for our customers, stated Tarun Jaswani, CEO and Founding father of Unbound Finance. There are some severe backers behind Unbound Finances $5.8 million elevate. Along with Pantera Capital and Michael Arringtons XRP Capital, the mission acquired direct funding from Hashed, Coin98 Ventures, LedgerPrime, CMS Holdings and lots of others. Over a dozen angel buyers additionally participated within the elevate, together with the founders of Angelist, Enjin, Gnosis, Kyber Community, Polygon, Concord, Polkastarter and others. Pantera CEO Dan Morehead commented on the affect Unbound Finance may have on the budding DeFi business:. ...

An arterial exam looks at the arteries in the body. Arteries carry blood to cells and organs. An upper extremity arterial evaluation examines blood flow in the arms and a lower extremity arterial evaluation examines arteries in the legs. Normally the inner wall of the arteries is smooth. When the inner lining becomes hard and thick, atherosclerosis (hardening of the arteries) develops. This can cause an artery to narrow (called a stenosis) or close off completely (called an occlusion). When this happens, blood must go through other blood vessels to get around the blockage causing alternate circulation called collateral circulation. Atherosclerosis occurs in all arteries to some degree however the arteries of the neck, heart and legs are most commonly affected. Peripheral Arterial Disease (PAD) refers to the blockages in the arms or legs.. An arterial evaluation is done to examine the arteries in the arms or legs to look at the blood flow to locate stenosis or occlusion.. An arterial ...

An arterial exam looks at the arteries in the body. Arteries carry blood to cells and organs. An upper extremity arterial evaluation examines blood flow in the arms and a lower extremity arterial evaluation examines arteries in the legs. Normally the inner wall of the arteries is smooth. When the inner lining becomes hard and thick, atherosclerosis (hardening of the arteries) develops. This can cause an artery to narrow (called a stenosis) or close off completely (called an occlusion). When this happens, blood must go through other blood vessels to get around the blockage causing alternate circulation called collateral circulation. Atherosclerosis occurs in all arteries to some degree however the arteries of the neck, heart and legs are most commonly affected. Peripheral Arterial Disease (PAD) refers to the blockages in the arms or legs.. An arterial evaluation is done to examine the arteries in the arms or legs to look at the blood flow to locate stenosis or occlusion.. An arterial ...

There is evidence of lateral STEMI with hyperacute T-waves in V5 and V6 and I and aVL. So this is consistent with circumflex occlusion. However, it is common for circ occlusions to show little on the ECG, at least in the literature. My experience is that there is nearly always evidence of it to an expert reader with a discerning eye. As for V1, RV involvement only happens with RCA ACS: with a proximal occlusion in which the RV does not get collateral circulation from the LAD, there can be RV STEMI with ST elevation in V1. These certainly can cause hypotension. In this case, the hypotension was due to poor LV function from LAD STEMI.. Delete ...

In the matter of section 156 of the Property Law Act 2007 and in the matter of the mortgage over goods (a specific security deed dated December 2015 and a Commercial Loan Facility dated 19 February 2020) over the following charged goods:. 2015 Mercedes-Benz Actros 3260/L48 Truck Registration No. JKL468 VIN WDB9302442L937339;. 2008 DAF XF 105 Truck Registration No. NKY163 VIN XLRAD47MS0E819110; and. 2020 Fruehauf RBC 5 axle trailer Registration No. 56G43 VIN 7A9RBC5SX0F007417. (collateral). Notice is hereby given that on 15 July 2021 Heartland Bank Limited entered into possession of the collateral.. Communications regarding the collateral may be addressed to Anthony Harper, PO Box 2646, Christchurch.. C. R. VINNELL, Solicitor for the Mortgagee.. ...

shows. The primary purpose of this device is to find out what processes are going on in our head at the moment. Assign a study of after a serious headache to prevent hemorrhage. The second useful action of REG is that determines the blood flow through the main, main vessels and the collateral circulation of the , that is, the flow of blood currents bypassing the main vessels, if for any reason they can not cope with their work. Before the invention of rheoencephalography, such ailments as neurocirculatory dystonia and migraine and diseases were not considered. To prove them from a medical point of view is almost impossible. A person is considered healthy. The organs function normally, which means that the person writhing with a headache,( and men are sick of migraines, too!) Is likely to be feigning. After all, amazingly, from the headache these people are helped only by those means that contain caffeine. And only the study REG regrouped everything in its place. She proved their presence in a ...

Depends: It depends if the vessel is an artery or a vein, the size of the vessel, collateral circulation, co-existing illnesses etc. Blood clot in a vein can travel to lung and cause lung infarction. Clot in an artery may damage the tissue/organ supplied by that artery. Heart attack is one example of clot in an artery. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex. ...Read more ...

The Arteriograph is a diagnostic instrument which is able to measure the severity of arteriosclerosis. This is the condition of arterial blockage caused by inflammation or damage within arteries followed by an over production of a compound known as plaque created by the body to repair the damage. Plaque is made up of cholesterol, minerals such as calcium, specialised red blood cells known as platelets and other clotting factors. The Arteriograph is a simple and painless, non invasive investigation that can diagnose arteriosclerosis at an early stage . Symptoms of arterial blockage include chest pain from blocking heart arteries, or the loss of sensation, numbness, or cramp in the lower limbs as the leg arteries block. These symptoms tend not to occur until a considerable amount of an artery is blocked and other arteries are no longer able to offer effective collateral circulation. Symptoms of cardiovascular disease leading to heart attacks and strokes usually appear only in the last and late ...

Each monthly episode will discuss recent publications in the fields of genomics and precision medicine of cardiovascular disease.

Annual precipitation in the largely agricultural South-Central United States is characterized by a primary wet season in May and June, a mid-summer dry period in July and August, and a second precipit

The Mammalian Phenotype (MP) Ontology is a community effort to provide standard terms for annotating phenotypic data. You can use this browser to view terms, definitions, and term relationships in a hierarchical display. Links to summary annotated phenotype data at MGI are provided in Term Detail reports.

We use cookies to ensure that we give you the best experience on our website. If you click Continue well assume that you are happy to receive all cookies and you wont see this message again. Click Find out more for information on how to change your cookie settings ...

All materials on this website are strictly copyrighted and may not be used without permission from the copyright holder. © 2017 Golgeon Group Inc. All rights reserved ...

Citi, Hong Kong, Hong Kong, Hong Kong job: Apply for Cash and Collateral Management Assistant Vice President in Citi, Hong Kong, Hong Kong, Hong Kong. Operations jobs available with eFinancialCareers.

NEW YORK - J.P. Morgan today announced that its Projections & Simulations service is now available globally. Part of the Securities Collateral Management product, Projections & Simulations provides se...

15th Annual Collateral Management Forum, Oct 2021 (Not Final), Amsterdam, Netherlands, organized by Fleming.. Find conference details | CLocate

Collateral Damage - StarCraft II - Legacy of the Void: A Short Story By: MATT BURNS A crowd stands outside the safe house on Anselm, the people shifting and jostling and craning their necks for a chance...