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Retrograde flow detection in the radial artery as a means to assess palmar collateral circulation in newborn infants.

The aim of this clinical study was to determine whether Doppler ultrasound can be used in newborn infants to assess the adequacy of palmar collateral circulation. Retrograde flow in the radial artery, distal to the site of manual occlusion of the vessel, was studied by Doppler technique. Forty-seven newborn infants, who underwent percutaneous radial artery cannulation were studied. Prior to cannulation palmar collateral circulation was tested in each infant, using the timed Allen test and was considered to be adequate. Pulsatile retrograde flow could be demonstrated in 11 out of 47 infants, but not in 36 of the 47 studied. During the period of cannulation none of the infants showed any sign of vascular insufficiency of the hand. It can be concluded that in newborn infants, the detection of pulsatile retrograde flow in the radial artery, using a Doppler flow meter, does not appear to have advantages over the Allen test as an indicator of adequate palmar collateral circulation.

Arteries↗

[Collateral circulation during exercise-induced angina: evaluation by coronary angiography].

The pathophysiological significance of coronary collateral vessels remains controversial, despite previous intensive studies. We performed the multistage supine ergometer stress test for 26 patients with effort angina and collaterals. The changes in the collaterals were observed during each anginal attack by coronary angiography before and after intravenous nitroglycerin. The collaterals of 21 patients disappeared or diminished during exercise-induced angina before nitroglycerin administration, and were unchanged in the remaining five cases. However, the collaterals of all patients after nitroglycerin administration were unchanged or increased during exercise-induced angina. Considering there were no significant changes in pulmonary arterial end-diastolic pressures during angina before and after nitroglycerin administration, a pressure gradient between the donor and recipient coronary arteries was suggested as being related to the patency of the collaterals. These results suggested the following: 1. It is not appropriate to postulate that the collaterals visualized at rest may remain unchanged during exercise-induced angina. 2. It is not reasonable to conclude that exercise accelerates the development of collateral circulation. 3. One favorable effect of nitroglycerin administration is the prevention of exercise-induced ischemia via collateral circulation.

Adult↗

Recognising stroke prone patients with a poor collateral circulation.

The prognosis in carotid disease is extremely variable and is influenced by the availability of collateral circulation. This study investigates the possibility of recognising patients with a poor collateral potential by using non-invasive tests. Preoperative OPG and EEG were compared with intraoperative EEG during test clamping in 208 carotid endarterectomies. Clamping ischaemia occurred in 29 patients (14%). Preoperative EEG had a sensitivity of 62% and a specificity of 82%. OPG showed a sensitivity of 96% and a specificity of 54%. Combined OPG and EEG resulted in a sensitivity of 93% and a specificity of 73%. Both tests are safe and easy to perform and interpret. These techniques can be used to identify those patients with carotid stenosis who have an increased risk of stroke due to a poor collateral circulation and may help to refine the indications for carotid endarterectomy.

Brain Ischemia↗

Ultrasound imaging versus morphopathology in cardiovascular diseases. Coronary collateral circulation and atherosclerotic plaque.

This review article is aimed at comparing the results of histopathological and clinical imaging studies to assess coronary collateral circulation in humans. The role of collaterals, as emerging from morphological studies in both normal and atherosclerotic coronary vessels, is described; in addition, present role and future perpectives of echocardiographic techniques in assessing collateral circulation are briefly summarized.

Cardiovascular Diseases↗

Significance of establishing collateral circulation by leptomeningeal anastomoses in the occlusion of arteriae cerebri mediae.

We have investigated establishment of collateral circulation in patients with cerebral circulation disorder. Thirty angiograms of patients treated at Neurological Department of Hospital Centre in Sarajevo suffering from arteriae cerebri mediae occlusion were used for this study. Cerebral anastomoses that included connections between arteriae cerebri anterior and arteriae cerebri mediae over leptomeningeal anastomoses occurred in some patients suffering from occlusion of this arteriae. It was concluded that the majority of anastomoses existed between big leptomeningeal branches of postcommunicant segment of a. cerebri anterior and branches of cerebri mediae. These collaterals are of great significance as their functional ability is sometimes of a high degree in cases of occlusion of one or the other artery. It can be concluded that anastomosing of the blood vessels increases their volume in the whole and therefore more blood can be provided, although physiological factors should not be neglected, as functional effectiveness of collateral circulation in postocclusive states depends also on the state of the whole cerebrovascular system, then on the speed of creation of occlusion (thrombosis or embolism), systemic arterial pressure, volume and viscosity of the blood.

Arterial Occlusive Diseases↗

Collateral circulation in distal occlusion of lower limb arteries: an anatomical study and statistical research in 40 elderly subjects by echo-color-Doppler method.

The collateral circles and their hemodynamic significance in distal lower limb arterial occlusion have been described in an elderly population. Overall 40 subjects (20 men and 20 women; age range 66-83) with symptomatic lower limb arteriopathy (Fontaine's stage II) have been studied combing Contrast Angiography and Color Doppler Echography of the lower limb arterial district. In our population, the results showed that the tibialis arteries were the vessels most often involved in arterial occlusion (posterior tibialis a., 15 cases = 37.5%, posterior tibialis a., 12 cases = 30%), followed by the peroneal a. (8 cases = 20%) and by the popliteal a. (5 cases, 12.5%). In the occlusion of the popliteal artery the collateral circle was mainly established through the deep femoral a., the great anastomotic a., the recurrent posterior tibialis a., and from the articular supero-lateral a. In the occlusion of the anterior tibialis artery the collateral circulation was ensured through the collateral posterior tibialis as. and through the collateral perineal as. In the occlusion of the posterior tibialis a., the collateral circle was established through the great anastomotic a., through the branchers of the arterial circle of the ankle and from the perforating plantar as. (anterior tibial a.). Finally, in the occlusion of the peroneal a., the collateral circulation was only represented by branches of the arterial circle of the ankle. The hemodynamic compromission, measured by the Windsor Index, was the highest for popliteal occlusions (mean IW = 34.3%). Occlusions of the anterior tibialis a. (mean IW. = 35.48%), of the peroneal a. (mean IW = 44.71%), and of the posterior tibialis a. (mean IW = 55.44%) showed progressively lower hemodynamic compromission. Gender differences in hemodynamic significance at each level of occlusion were not significant.

Aged↗

The anatomy and clinical significance of the collateral circulation between the internal and external carotid arteries through the ophthalmic artery.

Complete occlusion of the internal carotid artery is not necessarily associated with total disruption of cerebral blood flow distal to the site of the arterial obstruction. In fact, the flow of blood may be sufficient to maintain cerebral perfusion. This is accomplished by the shunting of blood from the external to the internal carotid artery by means of collateral circuits. While several major branch arteries of the external carotid artery may be recruited in this process, the ophthalmic artery is often the final common pathway before the anastomosis with the internal carotid artery. With the aim of elucidating these collateral circles, digital subtraction angiography was used to examine 100 patients with total occlusion of the internal carotid artery. These data were compared with those obtained using Doppler ultrasound, duplex scanning, and transcranial Doppler. Forty patients were excluded because there was no demonstrable collateral circulation, because the collateral circulation used the communicating arteries, or because the ophthalmic artery arose from the middle meningeal artery. Dynamic data were obtained by compressing the branches of the two external and common carotid arteries, and the blood vessels were identified by comparison with previous anatomic studies. We have constructed a precise map of the intra- and extracranial circles that connect the internal and external carotid arteries through the pathways that include the ophthalmic artery. This map demonstrates why apparently identical vascular occlusions may have divergent symptomatologies and clinical outcomes, which may range from the complete absence of symptoms to cerebral infarction.

Aged↗

[Disappearance of coronary collateral circulation during a crisis of spontaneous angina. The role of spasm].

Disappearance of the collateral coronary circulation was observed during an attack of spontaneous angina. During coronary angiography, the patient developed precordial pain, ST depression in Leads I, II, III, AVL, AVF, and V2 to V6. The two coronary arteries were opacified: there was no change in the left coronary tree but the collateral circulation arising from the right coronary artery and revascularising the obstructed left anterior descending artery the ECG reverted to its previous state and the collateral circulation reappeared. This case suggests that coronary artery spasm may lead to disappearance of the collateral circulation. It raises problems of methodology in the demonstration of spastic phenomena and emphasises the role of the collateral circulation in the genesis of ischaemia. It is another illustration of coronary artery spasm accompanied by ST depression.

Angina Pectoris, Variant↗

Coronary collateral circulation behaviour and myocardial viability in chronic total occlusion treated with coronary angioplasty.

AIMS: We explored the role of microcirculation integrity following the chronic occlusion of an infarct-related artery to assess the behaviour of collateral circulation during and after reperfusion by coronary angioplasty METHODS AND RESULTS: Eighteen patients with a proximally occluded left anterior descending artery and firm evidence of intercoronary collateral circulation were studied with selective coronary angiography and selective intracoronary myocardial contrast echocardiography, before coronary angioplasty, and at 5 and 15 min and 12 h later. Myocardial enhancement during myocardial contrast echocardiography was evaluated with a semiquantitative score (0-3), which was correlated to basal and 6 months' regional left ventricular wall motion results. 16/18 procedures were successfully performed; four patients with an inadequate acoustic window were excluded. Restenosis was evident at the 6 months' follow-up in two patients. Basal myocardial contrast echocardiography indicated that 81/192 segments from the left anterior descending coronary artery and 90/192 from the right coronary artery were perfused; no perfusion was observed in 21 segments either before or after coronary angioplasty. After coronary angioplasty, the angiographic intercoronary collateral circulation immediately disappeared, and myocardial contrast echocardiography revealed that there was a progressive reduction of segments perfused by the right coronary artery and an increase in segments perfused by the left anterior descending coronary artery. Regional left ventricular wall motion analysis demonstrated that there was abnormal motion in 51/192 segments. There was no improvement in segments with score 0 and abnormal motion after 6 months (100% sensitivity), but 16/17 segments with score 3 did show an improvement (98% specificity). The predictive value of intermediate scores (1-2) in detecting long-term improvement, was only 43%. CONCLUSION: These data show that the adaptive mechanism observed in the behaviour of epicardial and microvascular circulation after reperfusion of a chronic occluded infarct-related artery can vary. In addition, this study clearly shows that microvascular integrity detected by myocardial contrast echocardiography can provide myocardial viability.

Aged↗

Perioperative infarction: effects of cardiopulmonary bypass on collateral circulation in an acute canine model.

Significant intracoronary collateralization [circumflex (Cx) to anterior descending (AD)] can be established acutely by selective hypertensive perfusion of the circumflex (through left main) after acute occlusion of the AD in working canine hearts. Intracoronary collateral flow can be estimated by a collateral circulation index (CCI) = distal coronary diastolic pressure x 100/aortic diastolic pressure. The effects of 60 to 90 min of normothermic, total cardiopulmonary bypass (TCPBP) on such collaterals were evaluated in four dogs with CCI > 80%, and compared to six control dogs with CCI < 80% and without TCPBP. Three hours after AD ligation, control dogs had minimal myocardial injury despite significantly lower CCI. In contrast, the four study dogs placed on TCPBP experienced an abrupt fall of the CCI to 30% (P < 0.03), severe ischemia, and infarction in each; two became pump dependent. Thus, ventricular pressure work seems to be an important determinant of flow through collateral channels. These results suggest that preservation techniques for myocardium supplied by collaterals during coronary surgery may require considerations other than intermittent perfusion via existing coronary inflow.

Animals↗

Detection of human collateral circulation by vasodilation-thallium-201 tomography.

Coronary arteriolar vasodilation may provoke redistribution of flow to collateral-dependent jeopardized myocardium. To assess the physiologic significance of collaterals, 80 consecutive post-infarction patients (age 58 +/- 8 years) underwent vasodilation-redistribution thallium-201 tomographic imaging after administration of 0.56 mg of intravenous dipyridamole/kg body weight. Circumferential profile analysis of thallium-201 uptake and redistribution in representative left ventricular tomograms provided quantitative assessment of transient and fixed defects and separation between periinfarctional and distant inducible hypoperfusion. Tomographic perfusion data were correlated to wall motion and collateral circulation between distinct anatomic perfusion territories. Patients were grouped according to presence (59%) or absence (41%) of angiographically visible collateral channels to jeopardized myocardium. In the presence of collaterals, distant reversible defects were larger than in absence of collaterals (p less than 0.05); the extent of combined periinfarctional and distant redistribution was also larger in collateralized patients (p less than 0.025), whereas the size of the persistent perfusion defect was similar in both groups. By prospective analysis the tomographic perfusion pattern of combined periinfarctional and distant redistribution revealed a sensitivity of 85% and a specificity of 78% for the detection of significant collateral circulation in this group of patients. Thus, using the exhausted flow reserve as a diagnostic tool, vasodilation-thallium-201 tomography has the potential to identify and quantitate collateralized myocardium in post-infarction patients and may guide diagnostic and therapeutic decision-making.

Cardiac Catheterization↗

Dynamics of collateral circulation in progressive asymptomatic carotid disease.

Inadequacy of collateral arterial flow is the major risk factor for hemispheric infarction in association with spontaneous occlusion of the ipsilateral carotid artery. This prospective study was designed to measure the adaptation of collateral cerebral circulation through the circle of Willis in patients in whom a unilateral carotid stenosis of hemodynamic consequence develops asymptomatically. The collateral cerebral potential is assessed by ocular pneumoplethysmography (OPG) during proximal common carotid artery compression, measuring the collateral ophthalmic artery pressure (COAP). During an average follow-up of almost 3 years (maximum more than 7 years), 45 patients showed asymptomatic development of a unilateral hemodynamically significant carotid stenosis according to OPG evidence. In these patients the mean index COAP/brachial artery pressure did not change on the side of stenosis progression (p greater than 0.05). The developed carotid stenosis had only reduced collateral circulation to the contralateral hemisphere. The risk of inadequate collateral cerebral circulation remained during progression of asymptomatic extracranial arterial obstructive disease.

Adult↗

[Cerebral perfusion reserve and collateral circulation in patients with internal carotid stenosis].

The cerebral hemodynamics in patients with carotid disease is influenced by a network of extra- and intracranial collaterals. The purpose of this study was to compare the findings of regional cerebral perfusion reserve (rCPR) with angiographically proven collateral circulation. In 41 patients (28 men, 13 women, age 63 +/- 10 years) with angiographically proven carotid stenoses or occlusions (30 stenoses, 11 occlusions) 24 99mTc-HMPAO-SPECT and 25 dynamic Xe-CT investigations were conducted, both before and after acetazolamide stimulation. rCPR was quantified as the ratio (1) of the absolute rCBF values obtained by Xe-CT and (2) of the count density measured by HMPAO-SPECT of the acetazolamide administration. A rCPR of less than 95% in a vascular territory was classified as compromised rCPR. A recent CT examination was available in all cases. According to the angiographic findings the patients could be classified into (1) group A (n = 9) with residual carotid perfusion, (2) Group B (n = 8) with collateralization via the circle of Willis, and (3) group C (n = 24) with leptomeningeal or ophthalmic artery collateral circulation. The rCPR values were significantly different in groups B and C with both methods, Xe-CT (P = 0.0035) and HMPAO-SPECT (P = 0.0014). rCPR was decreased in 13/14 group C patients investigated with Xe-CT and in 11/14 examined with HMPAO-SPECT. All patients in group B showed normal rCPR according to Xe-CT and HMPAO-SPECT. In group A, six of seven revealed decreased rCPR on Xe-CT, while rCPR values were normal in all four group A-patients examined with HMPAO-SPECT. The cerebral hemodynamics depend on a collateralization network and not only on the degree of internal carotid artery (ICA) stenosis. A decreased CPR in a vascular territory ipsilateral to an ICA stenosis or occlusion correlates strongly with the angiographic finding of leptomeningeal or ophthalmic artery collateral circulation.

Aged↗

Complete occlusion of the left main coronary artery and the importance of coronary collateral circulation.

Study of four patients who survived complete occlusion of the left main coronary artery forms the basis of conclusions concerning the functional significance of coronary collateral circulation. Each of these patients had prominent collateral circulation from the right coronary artery. Global left ventricular function was maintained to the extent that congestive heart failure did not occur; the biplane ejection fraction was normal in the two patients where measurement was possible. The peak rate of systolic wall thickening by roentgen videometry in anterior left ventricular segments was normal in one patient and mild to moderately depressed in another. Experience with the patients described herein indicates that coronary collateral flow can provide critically needed circulatory support for the patient with coronary artery disease.

Collateral Circulation↗

Effect of Salvia Miltiorrhiza on coronary collateral circulation in dogs with experimental acute myocardial infarction.

To evaluate the effect of Salvia Miltiorrhiza on coronary collateral circulation in dogs with experimental acute myocardial infarction, 12 dogs were randomly divided into Salvia Miltiorrhiza group (group D) and control group (group C). Acute myocardial infarction model was established in all dogs, Salvia Miltiorrhiza or saline was administered to the 2 groups respectively for 21 days. Coronary angiography was performed before and after ligation of coronary artery. The capillaries and distribution vessel density in tissue sections of myocardia were assessed. Angiography 2 h and 22 days after ligation of coronary artery revealed significant augmentation of collateral vessels, and capillaries and distribution vessel density in ischemic zone on day 22 showed statistically significant augmentation in group D as compared with that of controls (P < 0.05 and P < 0.01). It is concluded that Salvia Miltiorrhiza might improve the opening and formation of coronary collateral circulation of ischemic myocardia in dogs and thereby protecting myocardia from ischemia.

Animals↗

[Pathophysiology of coronary collateral circulation in the human].

The functional relevance of coronary collaterals in humans has yet to be fully explored. Several studies demonstrated a protective role of collaterals in patients with coronary artery disease. On the other hand, negative aspects of well-developed coronary collaterals have been reported, e.g. a higher rate of restenosis following coronary angioplasty, or a redistribution of blood via collaterals away from the myocardial area in need towards normally perfused areas (coronary steal). In the past, the coronary collateral circulation has been assessed only qualitatively, using visual angiographic or nuclear imaging methods. With the recent advent of intracoronary Doppler and pressure-transducers, quantitative assessment of functional parameters of the coronary circulation has become feasible. This article reviews ongoing research in the field of coronary collaterals in humans, concerning their exact determination, the positive and negative aspects of their structure as well as their functional aspects.

Angioplasty, Balloon, Coronary↗

[A case of vasospastic angina: development of transient collateral circulation lessen the degree of myocardial ischemia during coronary artery spasm].

A 57-year-old man was admitted to our hospital because he had had attacks of chest pain at rest for more than a year, in spite of daily oral diltiazem (90 mg/day) and isosorbide dinitrate (15 m/day). The diagnosis of variant angina was made for him based on ST elevation in chest leads of the electrocardiogram during his first attack. However, one year later, the electrocardiograms during attacks showed only ST depression or T wave inversion in chest leads. The coronary arteriogram during spontaneous chest pain revealed that the left anterior descending artery was totally occluded at its middle portion, and that its peripheral portion was perfused by collateral circulation from the right coronary artery. The coronary arteriograms after administration of nitroglycerin were apparently normal, and no signs of collateral circulation were observed. These findings indicated that the transient collateral circulation could develop after repetitive coronary artery spasms even in the absence of significant coronary stenosis, and that it could lessen the degree of myocardial ischemia during coronary artery spasm.

Angina Pectoris, Variant↗