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Results for “Collateral Circulation”

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At least 145 records · Page 8Linked to original sources

PubMed1989

[Changes in platelet aggregation and coronary collateral circulation during the early phase of myocardial ischemia in dogs].

Experiments were performed on 18 anesthetized open-chest dogs to observe the changes in platelet aggregation and coronary collateral circulation during the early phase of acute myocardial ischemia. An increase in platelet aggregation rates (PAgR) and a decrease in platelet counts (PC) were found in the blood collected from the ischemic myocardium after coronary occlusion. PAgR was increased by 58.7 +/- 5.6% and PC was reduced by 39.5 +/- 23.6% at 50 min after occlusion (P less than 0.01). Under the condition of controlling aortic blood pressure, collateral coronary vascular capacity (CVC) was not changed (P greater than 0.05), but the effective collateral coronary flow to the ischemic zone, calculated by Wyatt et al's equation, was significantly reduced by 23.5 +/- 9.7% at 50 min after occlusion (P less than 0.05). There was a negative correlation between the changes in PAgR and the effective collateral coronary flow ( r = -0.857, P less than 0.01), and between the collateral indices and infarct size (r = -0.847, P less than 0.01). Abnormal changes in parameters of platelet and coronary collateral circulation after myocardial ischemia were nearly abolished by intravenous injection of aspirin before coronary occlusion. The results suggest that the deleterious changes of platelet aggregation during the early phase of the acute myocardial ischemia may decrease the effective collateral coronary flow significantly and thereby enlarge the infarct size.

Animals↗

PubMed1985

Superior portosystemic collateral circulation estimated by azygos blood flow in patients with cirrhosis. Lack of correlation with oesophageal varices and gastrointestinal bleeding. Effect of propranolol.

In patients with cirrhosis, superior portosystemic collateral circulation was evaluated by the continuous thermodilution method in the azygos vein. Azygos blood flow was 5 times higher in a group of patients with cirrhosis (alcoholic in 27, cryptogenic in 8, post-hepatitic in 2 and primary biliary cirrhosis in 1), than in a group of patients without portal hypertension (steatosis in 2, granulomatous hepatitis in 2, persistent chronic hepatitis in 2 and Hodgkin's disease in 1). Azygos blood flow was not different in cirrhotic patients with no visible, in those with small-sized, and in those with large sized oesophageal varices. Azygos blood flow was not different in cirrhotic patients with and without a previous episode of gastrointestinal bleeding. Fifteen min after intravenous administration of 15 mg of propranolol, azygos blood flow significantly decreased whereas azygos blood flow did not change after placebo. The decrease in azygos blood flow was significantly more marked than the reduction in cardiac output. It is concluded that superior portosystemic collateral blood flow is elevated in patients with cirrhosis and that the reduction in this collateral circulation might explain the efficiency of propranolol in the prevention of recurrent gastrointestinal bleeding.

Azygos Vein↗

PubMed1977

[Development of collateral circulation in the Paget-Schroetter syndrome].

An eleven years' clinical treatment of a 28-year-old tractor-driver with Paget-Schroetter's syndrome is described. The development of the collateral circulation was pursued during 6 years or 11 years, respectively, after the occurence of the vein thrombosis and the importance of phlebography in this rare disease is emphasized for the judgment of the prognosis. Phlebographic procedure is recommended for the reliable evaluation of the pathomorphological changes of the veins and of the developed collateral circulation.

Adult↗

PubMed1991

Collateral circulation in Kawasaki disease with coronary occlusion or severe stenosis.

Forty patients with Kawasaki disease with severe coronary sequelae were investigated. All had at least a 90% reduction in the diameter of the major coronary artery. Collateral vessels were seen in 32 of 33 (97%) patients with total occlusion. All patients with severe stenosis but not total occlusion had no or poorly developed collateral vessels. Analysis according to the presence or absence of collateral vessels showed no significant differences in the results of treadmill stress testing and myocardial imaging between these two groups. In patients treated surgically, the abnormalities recognized by these tests were normalized or improved when the bypass was patent. These data indicate that collateral circulation in patients with Kawasaki disease cannot be seen angiographically unless there is total occlusion and the presence of collateral circulation cannot provide protection against stress-induced myocardial ischemia.

Arterial Occlusive Diseases↗

PubMed1995

Noninvasive evaluation of the collateral circulation to the hand.

OBJECTIVE: To compare four methods of evaluating collateral blood flow to the hand. METHODS: The hands of 74 volunteers on the faculty or staff of a university hospital were studied prospectively. Only subjects without known peripheral vascular disease were included. Four tests were used in random order to assess radial and ulnar artery flow. Results of the assessments using the modified Allen's test, pulse oximetry, plethysmography, and laser Doppler perfusion monitoring were compared. RESULTS: No interrupted palmar arch was found. The modified Allen's test was normal in all cases. Pulse oximetry detected a 5% incidence of noticeably reduced blood flow in one artery compared with the other artery. This dominance of one artery was identified in 69% of the hands by plethysmography. The laser Doppler noted a dominant artery in 64% of the hands. Plethysmography and the laser Doppler disagreed in their findings in only 9% of the hands evaluated. Numerical values of blood flow, attainable only by the laser Doppler, were significantly lower upon occlusion of the radial vs the ulnar arteries (p < 0.05; paired t-test). CONCLUSION: All of the tests provide information about the collateral circulation to the hand. Only the laser Doppler provides quantitative blood flow. Further studies involving subjects most at risk for post-cannulation ischemic injury are needed to guide the clinical application of these findings.

Adult↗

PubMed1981

Collateral circulation between the external and internal carotid artery.

The most important anastomoses between the arteria carotis externa and interna are discussed, based on a study of several patients with obstruction of the arteria carotis interna. When the arteria carotis interna is obstructed, it is important to determine, as best as possible, the collateral circulation to the vessels distal to the occlusion, since the prognosis can partly depend on it, and because collateral circulation must be taken into account in evaluating operative possibilities.

Carotid Arteries↗

PubMedDate not supplied

Post occlusion ischemia in the territory of the internal carotid artery: role of the ophtalmic collateral circulation in relation to the status of the bifurcation.

Recent studies of the literature indicate that arteriosclerotic lesions located in the remnants of bifurcation and proximally to an occluded internal carotid artery can represent sites for the origin of emboli. Through the collateral circulation, these emboli can reach the homolateral cerebral territories producing further ischemic events. Two groups of patient, with angiographically proven internal carotid artery occlusion, one with, and another without irregular arteriosclerotic lesions (IAL) in the stump and/or external carotid artery, were followed up in order to determine the frequency of delayed post-occlusion ischemic events in each group. Ipsilateral events occurred more frequently when there was a stump associated with IAL in the remnants of bifurcation and signs of ophtalmic collateral circulation. This association may have prognostic value and should be considered before performing bypass procedures.

Adult↗

PubMed1989

[Noninvasive imaging methods and angiography in the diagnosis of chronic viscero-visceral arterial collateral circulation in stenosis of the celiac trunk].

Stenosis or even occlusion of truncus coeliacus represents the most frequent cause in the development of collateral blood circulation with caudiocranial flow through extended pancreatic-duodenal arcades. In a group of 32 patients with such mesenteric-coeliacal collateral circulation their arteriographic picture was evaluated. The authors evaluated differences and specific diagnostic contribution of individual visualization methods for demonstration of arteries. The non-invasive visualization methods are of exceptional contribution in the examination of abdominoretroperitoneal region by considerably decreasing the needs of invasive angiographic examination of catheterization technique. This leads to a decrease in the number of diagnosed chronically developed viscerovisceral arterial collateral circulations of various etiologies. Ultrasonography and computer tomography well depicts morphological changes in the aorta diameter as well as unpaired visceral arteries in the segment of their branching. The viscerovisceral arterial collateral circulations, however, may not be detected or at least not to a sufficient degree. They are represented in detail in the whole course only by selective arteriography. The authors draw attention to supplementary role of arteriography within the framework of non-invasive visualization methods.

Adult↗

PubMed1991

Exercise training and coronary collateral circulation.

This review examines the potential for an exercise-induced increase in coronary collateral circulation, with specific reference to the role and functional significance of collateral vessels, highlighting animal and human studies in particular, and their inherent methodological limitations. Exercise training may enhance myocardial oxygen supply by promoting transient periods of myocardial ischemia, a potent trigger of collateral growth. Some human studies have shown that moderate-to-high intensity training can result in a higher double product at the onset of angina and/or ischemic ST-segment depression, suggesting that myocardial oxygen supply has increased. Attempts to use thallium-201 exercise scintigraphy to assess myocardial perfusion before and after a physical training program have produced conflicting data, whereas angiographic studies in group trials have, without exception, yielded disappointing results. Thus, direct evidence that exercise stimulates collateralization in humans is lacking.

Animals↗

PubMed1989

Assessing collateral circulation in the hand--four methods compared.

Four ways to assess the collateral circulation in the hand were compared. No correlation was shown between the Doppler ultrasound method and those that used either the pulse monitor or the Ohmeda Biox 3700 pulse oximeter. The study was unable to confirm suggested benefits of these methods in assessing adequacy of collateral flow in the hands of unconscious patients.

Collateral Circulation↗

PubMed1992

Takayasu's arteritis with collateral circulation from the right coronary artery to intracranial vessels--a case report.

A forty-four-year-old woman with Takayasu's arteritis and involvement of the aortic arch and its main branches complained of precordial pain on effort. Exercise electrocardiograms revealed significant ST segment depression in leads II, III, aVF, and V. Coronary arteriograms demonstrated no stenosis. However, the right coronary arteriogram revealed collateral circulation arising from the sinus node artery to the bilateral vertebral arteries and the left internal carotid artery. The collateral circulation was considered to be an important route of blood flow supply to the brain and, at the same time, a cause of coronary steal syndrome and, consequently, of angina pectoris.

Adult↗

PubMed1991

Dipyridamole-induced decrement of functional recovery of postischemic reperfused myocardium in conscious dogs with well-developed coronary collateral circulation.

The effects of dipyridamole (20 and 40 micrograms/kg/min intravenously) on the time course of functional recovery of myocardium after five 5-minute coronary artery occlusions and four 5-minute reperfusions and a subsequent 5-hour reperfusion period were studied in chronically instrumented, conscious dogs with well-developed coronary collateral circulation. In comparison with vehicle-treated control dogs, those given dipyridamole (20 and 40 micrograms/kg/min, respectively) 15 minutes before and during coronary occlusion had a greater depression of regional segment shortening (38 +/- 7% and 19 +/- 4%, respectively, vs control levels of 69 +/- 10% of preocclusion values) during acute coronary artery occlusion. After a 5-hour reperfusion period, segment shortening returned to preocclusion values in the control group but remained decreased in the dipyridamole groups (87 +/- 4% and 75%, respectively). These results suggest that dipyridamole in a dose-dependent manner exacerbates recovery of contractility of postischemic reperfused myocardium in dogs with well-developed coronary collateral circulation.

Animals↗

PubMed1991

Importance of coronary collateral circulation for increased treadmill exercise capacity by nitrates in patients with stable effort angina pectoris.

The purpose of this study was to elucidate the mechanism that induces an improvement in exercise capacity by nitrates in patients with stable effort angina pectoris. The study population was composed of 19 patients: group A, 10 patients with chronic stable effort angina who had a well-developed coronary collateral circulation to the potentially ischemic region; group B, 9 patients with chronic stable effort angina who had no collateral circulation to the jeopardized myocardium. Treadmill exercise was performed according to the standard Bruce protocol with and without pretreatment with orally administered 10 mg isosorbide dinitrate. Percent increases (mean +/- SE) in exercise duration were not significantly different between groups A and B (25 +/- 6 vs. 14 +/- 6%). Percent increases in the maximal rate-pressure product tended to be greater in group A than in group B (27 +/- 6 vs. 10 +/- 6%). Percent increases in the rate-pressure product at the onset of angina pectoris were significantly greater in group A than in group B (37 +/- 7 vs. 7 +/- 6%; p less than 0.01). Percent increases in the rate-pressure product at 0.1 mV S-T segment depression were also significantly greater in group A than in group B (26 +/- 6 vs. 1 +/- 5%; p less than 0.01). These results suggest that isosorbide dinitrate dilates epicardial collateral vessels with smooth muscle layers, but fails to dilate the coronary arteries with significant organic stenoses.

Angina Pectoris↗

PubMed1991

The coronary collateral circulation in normal goats.

This study was undertaken to evaluate the coronary collateral circulation of the goat. Year old, castrated male goats were anesthetized with sodium pentobarbital. A branch of the left circumflex coronary artery was dissected and a snare placed around it. Regional myocardial blood flow was measured by injecting colored microspheres into the left atrium before and during 3 hr of occlusion of this coronary artery. The Area At Risk for infarction, as defined by a left atrial injection of Brilliant Green dye, was divided into a central Ischemic zone and a peripheral Ischemic Border zone. The degree of overlap in the blood flow distributions between the risk and the nonrisk areas was quantitatively assessed by injecting microspheres directly into the artery to the Area At Risk. Baseline blood flow to the normally perfused goat myocardium was 1.13 +/- 0.18 ml/min/g (mean +/- SE). Following occlusion, the flow to the Ischemic zone was 0.07 +/- 0.03 ml/min/g and to the Ischemic Border zone was 0.31 +/- 0.18 ml/min/g. Flow to either zone did not increase during the 3-hr observation period. Overlap at the perimeter of the risk and nonrisk areas was approximately 22%. We conclude that flow to the Ischemic zone is low because the goat has few native collateral blood vessels, and that flow to the Ischemic Border zone is significantly affected by overlap with normal myocardium.

Animals↗

PubMed1979

[Anatomical and physiological assessment of the collateral circulation in experimental femoral artery ligation in venous insufficiency].

Peculiarities of collateral circulation following isolated and combined ligations of the femoral vessels were studied in experiments on 62 dogs through physiologic and anatomic investigation methods. It has been shown that the ligation of the vein prevents the exsanguination of the limb, arising from an injury to the main artery, favours an accelerated anatomic reconstruction of the arterial collaterals, but increases microcirculatory disturbances, aggravates tissue ischemia and disorder of the acid-base balance, which as a whole evidences a detrimental effect of concomitant venous insufficiency upon the process of the restoration of the circulation in the limb.

Animals↗

PubMed1977

Collateral circulation after renal artery occlusion in the rat.

We used angiographic and microsphere methods to evaluate the anatomic and functional features of renal collateral circulation in the rat. By the microsphere method, renal parenchymal blood flow was less than 1% of control 1 hour after occlusion of the main renal artery; 2.8% of control 1-2 weeks after arterial occlusion; and 1% of control 4-9 weeks after occlusion. Radiographic observations during chronic occlusion revealed numerous collateral vessels to the kidney. These vessels readily filled with angiographic contrast medium but the intrarenal circulation did not visualize. We conclude that collateral circulation to renal parenchyma is negligible after acute or chronic occlusion of the main renal artery in the rat. The rich anatomic plexus of collateral vessels has no functional significance and is unable to preserve viability of the parenchyma.

Acute Disease↗

PubMed1989

[A case report of hypoplasia of the root portion and the intermediate portion of the left internal carotid artery associated with an unusual primitive collateral circulation between the left internal carotid artery and the left external carotid artery].

The internal carotid artery is one of the most stable arteries and its absence is very rare. We reported a case of hypoplasia of the root portion and the intermediate portion of the left internal carotid artery associated with an usual primitive collateral circulation between the left internal carotid artery and the left external carotid artery. A 57-year-old male developed right hemiparesis of sudden onset 3 days prior to admission. On admission, right hemiparesis and right minimal facial palsy was observed. The left direct carotid angiogram revealed that the root portion and the intermediate portion of the left internal carotid artery were hypoplastic. There was an unusual primitive collateral circulation between the left internal carotid artery and the left external carotid artery. From an embryological point of view, normally, the internal carotid artery is derived from the third aortic arch and the dorsal aorta when the embryo is attained the 3-mm stage. The root portion of the internal carotid artery is formed from the third aortic arch. The dorsal aorta between the third and the first aortic arch form the intermediate portion. The distal part of the internal carotid artery originates from the dorsal end of the first aortic arch. The common carotid artery begins to form in the 12-mm to 14-mm embryo, following involution of portion of the ventral aortic root between the third and the fourth aortic arch. The external carotid artery arises from the aortic sac and migrate up to the third aortic arch.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Thoracic↗

PubMed1980

[Collateral circulation syndromes in the brachiocephalic artery system].

In 56 patients qualitative and quantitative characteristics of variants of collateral circulation in the system of occluded brachiocephalic arteries were studied. The objects of the studies were angiographic and clinical appearance of the variants of retrograde blood flow and the latter's connection with cerebral circulation. It was shown that the reversion of the blood flow from the Willis circle system was observed in 25% of patients with occlusive affections of the brachiocephalic arteries. The most frequent was the flow through the spinal arteries. The subclavicular steal syndrome led to cerebral circulation disturbances that manifested mostly in the form of transitory disturbances of the circulation in the vertebrobasilar and less often the carotid basins of the cerebral circulation. The neurological disturbances were the most specific in patients with isolated affections of the brachiocephalic stem or the subclavicular arteries. At the same time the intensity of the retrograde flow from the Willis circle system is regulated by the level of cerebral circulation, and depends on the degree of the vasocerebral insufficiency.

Adolescent↗