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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↗

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↗

Detection of peripheral microemboli through collateral circulation by Doppler ultrasound monitoring-report of 2 cases.

It is possible for a proximal arterial source to lead to distal atheroembolism even in the presence of chronic occlusive disease. However, no monitoring technique has been established regarding detection of peripheral emboli through the collateral circulation in the lower limbs. We report a 60-year-old woman and a 73-year-old man with iliac stenosis and complete occlusion of the ipsilateral superficial femoral artery in whom Doppler ultrasound successfully detected microembolic signals (MES) at the tibioperoneal trunk during percutaneous transluminal angioplasty (PTA) and stent placement. By means of continuous Doppler ultrasound monitoring, 29 MES were successfully detected immediately after PTA or stent placement (MESp) and 64 MES were detected immediately after the contrast medium administration (MESc). MESc generated significantly higher intensities (median 28, range 7 to 38) as opposed to MESp (median 21, range 5 to 35, p = 0.017). In addition, the intensity of MES after prestent PTA (n = 8, 25 dB, 12-35 dB) and stenting (n = 18, 22 dB, 9-35 dB) was significantly higher than that of MES after poststent PTA (n = 3, 13 dB, range; 5-16 dB), respectively (p = 0.041, p = 0.034). Iliac PTA and stent placement were successful. Ankle/brachial pressure index and the symptoms improved in both patients, who showed no embolic symptoms after the procedure. This study suggested that it was possible to detect peripheral microemboli through the collateral circulation by Doppler ultrasound monitoring and that this technique would be helpful to investigate the mechanism of embolization in patients with PTA and stent placement.

Aged↗

Aortic foreign body resulting in ischemic neuromyopathy and development of collateral circulation in a cat.

A cat evaluated for paraplegia had firm pelvic limb musculature and did not have femoral pulses. External wounds were not evident, but abdominal radiography revealed a round metallic foreign body on the midline ventral to the sixth lumbar vertebra. Angiography indicated stenosis or thrombosis of the aorta in association with the foreign body; collateral circulation arose from the fifth lumbar artery. Arteriotomy was performed to extract the foreign body and associated thrombi. Six weeks after surgery, angiography revealed blood flow in the abdominal portion of the aorta, but no evidence of obstruction or additional collateral vessels. The cat regained function of the pelvic limbs within 1 year after surgery. Ischemic neuromyopathy and paraplegia in cats is commonly associated with aortic thromboembolism. A thrombus is necessary to cause typical clinical signs, and vasoactive substances released by platelets in the thrombus are believed to cause ischemic neuromyopathy. Progression of the collateral circulation may allow for clinical improvement without surgical intervention.

Animals↗

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↗

[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↗

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↗

[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↗

[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↗

[Effects of repetitive myocardial ischemia on collateral circulation, ST deviation and epicardial wall motion].

The effects of repetitive myocardial ischemia on collateral circulation, ST deviation and epicardial wall motion were examined in 12 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) for single left anterior descending artery disease. Rentrop collateral filling grade was assessed using contrast injection to the contralateral artery during the first and final episodes of coronary occlusion. ST deviation was measured by intracoronary electrocardiography. Epicardial wall motion (%pre PTCA) was measured by guide wire motion analysis according to the centerline method. Collateral filling grade was assessed 30 sec after balloon inflation. The ST segment and the epicardial wall motion were measured 60 sec after balloon inflation and deflation, respectively. There was no change in the collateral filling grade between the first and final episode of coronary occlusion. Patients with collateral filling grade I (R-I group, n = 4), II (R-II group, n = 3) and III (R-III group, n = 5) during coronary occlusion showed mean ST segment shifts of 13.2, 9.4, and 0.9 mm, respectively, and mean epicardial wall motion of 41.4%, 67.2%, and 78.5%, respectively. The collateral filling grade correlated with ST deviation and epicardial wall motion, and there was a significant correlation between epicardial wall motion and ST deviation (r = -0.67). Comparison of the R-I group or severe ischemia (n = 4) and the R-III group or slight ischemia (n = 4) during coronary occlusion for the fourth time showed the effect of preconditioning was obtained in R-I group. More R-III group patients than R-I group had hyperkinetic epicardial wall motion during coronary reperfusion. Stunned myocardium was demonstrated in both R-I group and R-III group patients. Epicardial wall motion was poorer in the R-I group than R-III group. We concluded the following: There is no change in the grade of collaterals during repetitive coronary occlusion, and there is a relationship between the grade of collateral and degree of myocardial protection; there is good correlation between ST segment and epicardial wall motion; ischemic preconditioning is obtained during repetitive severe myocardial ischemia; recovery from brief episodes of slight myocardial ischemia is associated with hyperkinesia of epicardial wall motion; the reduction of stunned myocardium is related to the degree of premyocardial ischemia; preconditioning is sufficient to cause myocardial stunning, but myocardial stunning is insufficient to cause preconditioning.

Aged↗

Cavernous transformation of the portal vein: patterns of intrahepatic and splanchnic collateral circulation detected with Doppler sonography.

OBJECTIVE: Cavernous transformation of the portal vein is defined as the formation of venous channels within or around a previously thrombosed portal vein. The purpose of this work was to study the hemodynamic consequences of cavernous transformation of the portal vein in a group of afflicted patients by use of Doppler sonography. We wished to study the evolution from portal vein thrombosis to the formation of cavernous transformation, the extent of resulting extrahepatic collateral channels, and the patterns of splanchnic collateral circulation. MATERIALS AND METHODS: Seventy-five patients (48 adults and 27 children) with cavernous transformation of the portal vein were studied with color and/or pulsed Doppler sonography. Blood flow in the extrahepatic portal vein, in its segmental branches, in the hepatic veins and artery, and in the splanchnic veins was examined. Collateral pathways were sought. For nine patients with acute thrombosis of the portal vein, serial examinations were performed during the formation of cavernous transformation. RESULTS: In nine patients, a fresh thrombus filled and distended the portal vein and became recanalized within a few days. Tortuous vessels appeared at the porta hepatis. These were characterized as veins or arteries with Doppler sonography. Soon the portal vein could no longer be identified within the mass of tortuous vessels. The cavernous transformation developed within 6-20 days of the acute thrombosis. A spongelike mass of collateral vessels around the main portal vein was seen in all but two patients. Intrahepatic extension of the cavernous transformation was seen in 57 patients (76%) and involved one or more intrahepatic portal veins. Two types of collateral circulation were observed: portosystemic, mainly through the left gastric and the perisplenic veins (the caput medusae, i.e., the paraumbilical-to-abdominal venous route, was never seen); and portoportal, from the periportal or pericholecystic venous channels to the intrahepatic portal veins. In nine patients, flow within unaffected intrahepatic branches of the portal vein was reversed as directed toward the cavernous transformation surrounding other, thrombosed intrahepatic segments of the portal vein. CONCLUSION: After thrombosis of the portal vein, portoportal venous channels may form not only at the porta hepatis but also within the liver. Intrahepatic blood may be shunted from one segmental portal vein to another. In addition, portosystemic collateral channels are formed, suggesting that, despite extensive hemodynamic adaptations, portal hypertension ensues.

Acute Disease↗

[Importance of the orbital collateral circulation for the origin of ischemic ophthalmopathy in stenotic diseases of the internal carotid artery].

Ischemic ophthalmopathy is the leading ocular symptom of occlusive processes of the internal carotid artery. It can be preceded by embolic symptoms as amaurosis fugax or occlusion of a branch or the main stem of the central retinal artery. Both, ophthalmologists and neurologists, should be familiar with these disturbances as they can involve important diagnostic and therapeutic consequences. Five out of six patients with an angiographically demonstrated extracranial occlusion of one internal carotid artery and a retrograde collateral circulation to the intracranial space via the external carotid and the ophthalmic arteries showed an ischemic ophthalmopathy of the ipsilateral eye. This high coincidence supports the notion that an ischemic ophthalmopathy may not be the result of the occlusive process of the internal carotid artery per se, but may be caused by ocular "steal mechanisms" due to the retrograde orbital collateral circulation.

Adult↗

[Does ST-elevation in stress ECG depend on the extent of collateral circulation?].

As a possible cause of exercise-induced ST-elevation in patients without myocardial infarction, a poor or absent coronary circulation to the poststenotic coronary segment was postulated. To check this thesis, we examined 10 patients (pts.) with ST-elevation, respectively, ST-depression and comparable coronary status (coronary score 12 vs. 12; mean stenosis diameter 86 vs. 85%) and exercise parameters (work load 150 vs. 137.5 Watts; exercise duration 2.8 vs 3.5 min) with regard to their collateral circulation. In the group with ST-elevation there were nine pts. with severe proximal stenosis of the left anterior descending artery (LAD) and one pt. with a stenosis in the middle third of the right coronary artery. The 10 patients with ST-depression had a proximal stenosis in the LAD. The extent of the angiographically seen collaterals was equal in both groups. As a result, this study demonstrates that the size of the collateral circulation has no influence on the exercise-induced ST-elevation. The most plausible cause of exercise-induced ST-elevation is a functional decrease of the lumen of a severe stenosis.

Arrhythmias, Cardiac↗

"True" aneurysm of the posterior communicating artery as a possible effect of collateral circulation in a patient with occlusion of the internal carotid artery. A case study and literature review.

"True" posterior communicating artery (PCoA) aneurysms are extremely rare. A case of a 63-year-old patient with a ruptured "true" aneurysm of the right PCoA associated with the occlusion of the right internal carotid artery is presented. For nine years before he suffered from subarachnoid hemorrhage, the patient had developed symptoms of transient ischemic attack (TIA) due to the occlusion of the right internal carotid artery. The left vertebral angiogram demonstrated a "true" right PCoA aneurysm and collateral flow from the right posterior communicating artery to the right internal carotid artery. The right internal carotid system was also fed by collateral circulation from the left carotid artery through the anterior communicating artery. Transcranial colour-coded real-time sonography (TCCS) demonstrated increased velocity and turbulent blood flow in both communicating arteries. The patient was operated on and the aneurysm was clipped successfully. This case report suggests that the blood flow disturbances resulting from the collateral circulation through the PCoA could be a conductive factor in the formation and development of the aneurysm. This is the first described case of a "true" aneurysm of the PCoA coexistent with the occlusion of the internal carotid artery.

Aged↗

Effects of VEGF121 and/or VEGF165 gene transfection on collateral circulation development.

BACKGROUND AND PURPOSE: Angiogenesis is regulated by various factors, including vascular endothelial growth factor (VEGF). Five isoforms of VEGF have been discovered: VEGF121, VEGF145, VEGF165, VEGF189, and VEGF206. The teleologic basis for the various VEGF isoforms remains unclear, but different VEGF isoforms may mediate distinct endothelial cell functions such as angiogenesis, vascular permeability, and differentiation. We sought to determine the effects of various VEGF isoforms on angiogenesis under ischemic conditions in rabbits. METHODS: The effects of VEGF121 and/or VEGF165 gene transfection on collateral circulation development in ischemic rabbit hindlimb muscles were investigated by using naked plasmids encoding VEGF121 or VEGF165 (pVEGF121 or pVEGF165), either individually or in combination. pCMV beta was used as the control plasmid. The femoral artery on one side of New Zealand White rabbits was ligated. Ten days later, the ischemic muscles received direct intramuscular injection of pVEGF121 (500 micrograms), pVEGF165 (500 micrograms), or pVEGF121 (250 micrograms) + pVEGF165 (250 micrograms) in experimental groups, while pCMV beta (500 micrograms) was used in the control group. Therapeutic effects were evaluated 30 days later by anatomic and physiologic analysis. RESULTS: Internal iliac angiography showed strong development of collateral circulation in all of the pVEGF-treated groups. In contrast, collateral arteries developed weakly in the control group. Combination treatment with both pVEGF121 and pVEGF165 did not result in additional improvement compared with pVEGF121 or pVEGF165 treatment alone (angiographic scores: pVEGF121 = 0.85 +/- 0.10; pVEGF165 = 0.81 +/- 0.11; pVEGF121 + pVEGF165 = 0.83 +/- 0.09; control = 0.53 +/- 0.09; p < 0.01). A favorable response in the development of circulation at the capillary level with pVEGF121 and/or pVEGF165 versus pCMV beta was also found. Blood pressure measurement and regional blood flow measurement using colored microspheres revealed similar results. CONCLUSIONS: Our results show that direct intramuscular injection of naked DNA encoding VEGF121 or VEGF165, individually or in combination, is an effective method for gene transfer in an animal model of ischemic limbs and results in augmented collateral vascular development and tissue perfusion.

Angiography↗

[A ruptured aneurysm at the peripheral collateral circulation of the anterior choroidal artery in a patient with moyamoya disease: a case report].

This 42-year-old man experienced a sudden onset of occipital headache. Neurological examination revealed a moderately disturbed consciousness and a moderate left hemiparesis. CT scan disclosed a hugh hematoma in the right temporo parietal lobe without intraventricular hemorrhage. A cerebral angiography demonstrated typical findings of moyamoya disease and a small saccular aneurysm at the peripheral portion of the right anterior choroidal artery, which was dilated at the collateral circulation to the parietal lobe. The hematoma was removed at once by a craniotomy. He became alert but mild hemiparesis persisted. MRI disclosed a small signal-void lesion lateral to the trigone of the right lateral ventricle. The angiography repeated three weeks after the removal of the hematoma showed the unchanged size of the aneurysm. Direct surgery for the aneurysm was performed via the right parietal transcortical approach. The aneurysm was reached under the guidance of the intraoperative angiography. Trapping of the parent artery and the excision of the aneurysm were performed. On the basis of the presence of an internal elastic lamina at the neck of the aneurysm, the surgical specimen was histologically verified to be a true aneurysm. Since the collateral circulation was well preserved during surgery, no worsening of the neurological manifestation was observed. In view of the unfavorable prognosis for a moyamoya patient with this type of the aneurysm, which often results in a massive ventricular or intracerebral hemorrhage, surgery directed to the aneurysm itself should be considered.

Adult↗

[Formation and function of coronary collateral circulation and their influencing factors].

OBJECTIVE: To clarify the formation and function of coronary collateral circulation (CCC) in coronary artery disease (CAD) patients with severe coronary artery stenosis and their influencing factors. METHODS: Coronary angiography was performed on 266 CAD patients with severe coronary stenosis. CCC formation was evaluated by Rentrop rating on those 266 patients and 401 severe stenosis arteries; while in CCC formed patients, CCC function was evaluated by Werner collateral collection (CC) rating. The formation, function of CCC and their influencing factors were analyzed and compared. RESULTS: CCC formation in those severe stenosis coronary arteries was related to the severity of coronary stenosis: the forming rate of CCC was 42.6% in vessels with 90%-94% stenosis (Group A), 56.9% with 95%-99% stenosis (Group B) and 93.0% with 100% stenosis (Group C) (p <0 .01). Between CCC forming and non-forming groups, there was no significant difference in age, gender, incidence of MI, hypertension and diabetes, history of smoking and serum levels of HDL-C and LDL-C (P > 0.05). In the CCC formation group, serum HDL-C level was the highest in the CC Grade 2 group (according to Werner function rating) and the lowest in the CC Grade 0 group (P < 0.05). Whereas, LDL-C level was the lowest in the CC Grade 2 group and the highest in the CC Grade 0 group (P < 0.05). CONCLUSION: Severity of coronary stenosis was the major influencing factor in CCC formation and function, and the rate of CCC formation increased with the exacerbation of coronary stenosis. Serum HDL-C and LDL-C level had no relationship with CCC formation, but related to CCC function. Better CCC function was found in patients with high level of HDL-C whereas the patients with high level of LDL-C had spoiled CCC function.

Cholesterol, HDL↗