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Results for “Collateral Circulation”

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PubMed1986

Limitation of myocardial ischemia by collateral circulation during sudden controlled coronary artery occlusion in human subjects: a prospective study.

We have shown improvement in collateral filling immediately after sudden controlled coronary occlusion in human subjects undergoing elective coronary angioplasty. It has been suggested but not proved that collateral circulation can limit myocardial ischemia. We prospectively studied 23 patients with isolated left anterior descending (n = 14) or right coronary (n = 9) disease and normal left ventriculograms during elective coronary angioplasty. A second arterial catheter was used for injection of the contralateral artery to assess collateral filling before balloon placement and during coronary occlusion by balloon inflation. Left ventriculography was performed during another inflation. Grading of collateral filling was as follows: 0 = none, 1 = filling of side branches only, 2 = partial filling of the epicardial segment, 3 = complete filling of the epicardial segment. Indexes of myocardial ischemia included percent of the left ventricular perimeter showing new hypocontractility and the sum of ST segment elevation measured on a simultaneous 12-lead electrocardiogram recorded during each inflation. Collateral filling during balloon occlusion and indexes of ischemia were assessed at 30 to 40 sec into inflation. Aortic pressure and heart rate did not correlate with the percent hypocontractile perimeter nor the sum of ST segment elevation. There was a significant correlation between the grade of collateral filling during inflation and both percent hypocontractile perimeter (r = -.85) and the sum of ST segment elevation (r = -.87). Anginal pain occurred in all patients with grade 0 or 1 collateral filling but in only 36% of patients with grade 2 or 3 collaterals. In conclusion, collateral circulation limits myocardial ischemia as assessed by the extent of new ventricular asynergy and electrocardiographic changes during coronary occlusion in patients.

Aged↗

PubMed1986

Effects of collateral circulation on electrophysiological properties during the acute phase of canine myocardial infarction.

To investigate the effect of collateral circulation on the electrophysiological properties of the acutely ischemic myocardium, acute myocardial infarction was produced in the canine heart by coronary artery occlusion alone, and by coronary artery occlusion plus embolization with vinyl latex. Multiple bipolar electrodes for stimulation or for recording electrograms were placed on the subepicardial layer and the subendocardial layer to examine the time course of changes in excitability threshold, effective refractory period, and conduction time. Soon after coronary occlusion plus embolization, electrophysiological properties of the ischemic subepicardium became severely and almost uniformly damaged and showed no recognizable recovery of electrical activities, whereas transient deterioration and subsequent recovery of the electrophysiological properties were observed after coronary occlusion alone. On the other hand, the subendocardium was much less affected electrophysiologically by either coronary occlusion alone or coronary occlusion plus embolization. These results indicate that collateral circulation plays an important role in the recovery from electrophysiological abnormalities in the ischemic subepicardium caused by acute myocardial ischemia, but has little effect on the electrophysiological properties of the ischemic subendocardium.

Animals↗

PubMed1975

Gas exchange in the pulmonary collateral circulation of dogs. Effects of alveolar hypoxia and systemic hypoxemia.

The left main pulmonary artery was ligated in 7 fully grown dogs. This resulted in an enlarged pulmonary collateral (systemic) flow to the left lung. By collecting gas from each lung separately, gas exchange in the pulmonary collateral circulation was studied and compared to that in the normal contralateral side. Studies were done repeatedly during a period of 3 years. Compared to that in the preoperative period, the ligated (left) side showed a decrease in ventilation (42.5 to 34.5 per cent of total), a marked increase in wasted ventilation (0.30 to 0.55), and a marked decrease in O2 uptake (45 to 11.2 per cent of total) and CO2 production (27.5 to 15.3 per cent of the total). There were no changes in arterial blood gases or pH. A significant, sustained, systemic hypertension was noted in all dogs in which the left main pulmonary artery was ligated (190/120). The mean blood flow through the pulmonary collateral circulation of the left lung with the dogs breathing room air was estimated to be 94 ml per min. When the dogs were made hypoxemic by breathing 12 per cent O2 through the normal right lung, there was a marked increase in pulmonary collateral (systemic) flow to the contralateral side (194 ml per min). This resulted in an increase in O2 consumption (29.4 per cent of total) and CO2 production (23.1 per cent of total) of the left lung. When the dogs were given 12 per cent O2 to breathe through the ligated left lung, there was no change in arterial PO2. There was a significant increase in blood flow through the pulmonary collateral circulation to 136 ml per min. Because of the gradient of O2 between the blood flowing into the left lung and that present in the alveoli, there was a net production of O2 from the left lung of 4.5 ml per min. When the pulmonary systemic circulation participates in gas exchange, it appears to increase during hypoxemia as well as during alveolar hypoxia.

Animals↗

PubMed1988

Effect of aging on collateral circulation via pial anastomoses in cats.

The effect of aging on collateral circulation via pial anastomoses after middle cerebral artery occlusion was investigated in young and aged cats. The reduction of blood flow and electroencephalography power were greater and collateral vessel resistance was higher in the aged group than the young group. Electroencephalography power after the occlusion was correlated with collateral resistance and blood flow in the two groups. These results suggest that collateral function deteriorates with aging and the high vulnerability to ischemic insult in aged brain may be caused in part by the poor collateral function.

Aging↗

PubMed1987

Ameroid constriction of the proximal left circumflex coronary artery in swine. A model of limited coronary collateral circulation.

Gradual narrowing and occlusion of a coronary artery in patients with atherosclerotic heart disease frequently causes enlargement of the collateral circulation. Although these vessels may protect from development of myocardial infarction, they frequently do not supply sufficient blood flow to prevent ischemia during periods of augmented myocardial oxygen demand. The purpose of this study was to develop a model of the collateral circulation in pigs, a species that previously has been shown to develop sparse collateral vessels. Eighteen pigs were instrumented with an Ameroid constrictor around the proximal left circumflex artery and left atrial and aortic catheters. In four animals the constrictor was placed just distal to a large proximal obtuse marginal vessel. Seven of the pigs were treated daily with oral aspirin (325 mg) and disopyramide (200 mg) throughout the study; the other 11 served as controls. After an average of 24 days postoperatively, radioactive microspheres were injected at rest, during exercise (mean heart rate = 245 beats/min), and during intravenous infusion of dypridamole (700 micrograms/kg). At autopsy the extent of necrosis was assessed by a point counting technique in the bed at risk. We found that 75-83% of the bed at risk remained viable. Although aspirin and disopyramide did not significantly alter the extent of infarction (37 +/- 36% untreated vs 17 +/- 6% treated), there was less variability of infarction in the treated group, and subendocardial blood flow during exercise was higher in the treated group compared to controls. The majority of infarction occurred in the subendocardial region. Animals with a large obtuse marginal branch developed significantly smaller infarcts (8 +/- 3%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1979

[The collateral circulation due to cerebral arterio-venous malformation and occlusions of major cranial vessels (author's transl)].

Arteriovenous malformations (AVM) of the brain are diagnosed mostly in the early adult life. With the come up of Computerized Tomography (CT) which often is done without the strong indications as postulated for the conventional neuroradiologic examinations, asymptomatic AVM in the elderly population may be found. Since May 1977 4 asymptomatic arteriovenous malformations were diagnosed in our institution using CT. 2 of these patients had severe degenerative changes of the great cerebral vessels and an unusual collateral circulation developed probably because of the steal-phenomenon in the vascular malformation. These 2 cases allow to study all possibilities of cerebral collateral circulation. Uncommon in one of the cases was a capillary anastomotic network through the thalami, in the other case an extensive dural rete mirabile developed. The problems of collateral circulation are discussed.

Cerebral Angiography↗

PubMed1980

[Collateral circulation via the arterial network of the neck in subclavian artery occlusion].

The authors describe three different varieties of collateral circulation via the so called arterial network of the nape of the neck in patients with proximal subclavian artery occlusion. Attention is called to the importance of cervical veins visualization for the evaluation of the efficiency of the collateral circulation and prognosis about the further state of the patient. The authors propose a modification of angiography with additional films taken of the subclavian area in late arterial phase making possible to demonstrate the site of subclavian artery occlusion during carotid angiography.

Adult↗

PubMed1992

Evaluation of collateral circulation of the hand.

In 1929, Edgar V. Allen described a noninvasive evaluation of the patency of the arterial supply to the hand of patients with thromboangitis obliterans (Am J Med Sci 1929; 178:237). In the early 1950s, Allen's test was modified (Wright I. Vascular diseases in clinical practice. Chicago: Year Book Medical Publishers, 1952) for use as a test of collateral circulation prior to arterial cannulation. This test involves the examiner occluding the patient's ulnar and radial arteries while the patient makes a fist, causing the hand to blanch. The patient is then asked to extend the fingers. After the hand is open, the examiner releases the ulnar artery while continuing to maintain pressure on the radial artery. Adequate collateral circulation is felt to be indicated by return of normal color to the hand. The patient is instructed not to hyperextend the fingers when opening the hand. Hyperextension may cause a decrease in perfusion to the arch, possibly resulting in a false interpretation of the Allen test (Anesthesiology 1972;37:356). The modified Allen's test can be performed quickly and easily, but it is susceptible to error. (With Allen's original test, both hands were tested simultaneously. The patient clenched both fists tightly for 1 minute while the examiner compressed one artery of each hand. This method helps diagnose complete occlusion, just as Allen intended. The test was later modified, however, to evaluate the adequacy of collateral circulation. To perform the modified Allen's test, the examiner compresses both arteries while the patient's fist are clenched.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1979

Collateral circulation in the rabbit tongue after common carotid ligation.

A study was undertaken to ascertain the microvascular pattern of the collateral circulation of the tongue after unilateral ligation of the common carotid artery. The right common carotid artery was ligated in 25 New Zealand White male rabbits. These animals were killed in groups of five at intervals of an hour, six hours, 24 hours, one week, and two weeks. The vasculature in the head and neck of these animals was flushed with heparinized saline solution and perfused with latex. The results show that circulation was present but signifincatly reduced in the one-hour group, slightly reduced in the six-hour and 24-hour groups, and normal in the one- and two-week groups. This study indicates that the collateral circulation of the tongue is extensive and that a normal vascular pattern returns within a week after unilateral ligation of the common carotid artery.

Animals↗

PubMed1987

Functional significance of alpha-adrenergic receptors in mature coronary collateral circulation of dogs.

There is little information on the functional significance of alpha-adrenergic receptors in the dog's coronary collateral circulation. Accordingly, we investigated the effects of infusion of either norepinephrine (NE) or B-HT 920 (BHT), an alpha 2-adrenergic agonist, on vascular resistance of coronary collaterals in chloralose-anesthetized dogs 2-3 mo after placement of an Ameroid constrictor around the left circumflex coronary (LCX) artery. To accomplish this, the vagotomized left ventricle was autoperfused through the left main coronary ostium using a servo-controlled constant-pressure pump. Pressures of the left anterior descending (LAD) and peripheral LCX arteries were measured, and regional blood flow in LAD and LCX regions were determined with radioactive microspheres before and during NE infusion in the unblocked condition, following beta-adrenergic and beta + alpha 1-adrenergic blockade with the use of propranolol and prazosin, respectively. The same parameters were also measured before and during BHT infusion following beta-adrenergic and beta + alpha 2-adrenergic blockade with the use of propranolol and idazoxan, respectively. In the unblocked condition, NE reduced LAD, LCX, and collateral resistance by 43, 50, and 31%, respectively. After beta-adrenergic blockade, NE increased LAD resistance (29%) but did not alter LCX or collateral resistance. The increase in LAD resistance was abolished following alpha 1-adrenergic blockade. BHT increased vascular resistance in LAD, LCX, and collateral circulations by 35, 29, and 45%, respectively. Selective alpha 2-adrenergic blockade significantly attenuated the vasoconstrictor response to BHT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗

PubMed1995

Use of Tc-99m HMPAO brain SPECT to evaluate cerebral collateral circulation during Matas test.

Five patients with traumatic carotid-cavernous fistulae and two patients with internal carotid artery aneurysms inside the cavernous sinus are presented. A quantitative method was used for the evaluation of brain collateral circulation in the anterior and middle cerebral artery territories by using Tc-99m HMPAO SPECT before and during the Matas test. It affords a more reliable quantitative measurement of reduced activity than conventional carotid angiography during the Matas test. In this study, a reduction of radioactivity of less than 15% during the Matas test did not reveal any postoperative neurological deficit after a carotid artery trapping procedure. This noninvasive method seems to be useful to determine the appropriate surgical treatment.

Adult↗

PubMed1984

Temporal evolution of the human coronary collateral circulation after myocardial infarction.

An analysis of the coronary collateral circulation in a consecutive series of 116 postinfarction angiograms from patients with persistent 100% occlusion of their infarct artery is reported. Patients were classified into four groups according to the interval between acute infarction and angiography. Of 42 patients studied within 6 hours of infarction (Group I), 52% had no evidence of any coronary collateral development as compared with only 8% (1 of 16 patients) studied 1 day to 2 weeks after infarction (Group II). Virtually all patients studied beyond 2 weeks after myocardial infarction (14 to 45 days, Group III) and later than 45 days (Group IV) had visible collateral flow. Angiographically "well developed" collateral channels were seen in only 16% of Group I patients compared with 62, 75 and 84% of patients in Groups II to IV, respectively. Of six patients studied twice, on the day of the infarction and 2 weeks later, only one patient had collateral vessels on the day of infarction, whereas all six patients did at follow-up study. Group I patients were studied as part of a randomized acute myocardial infarction reperfusion trial, whereas the other patients were referred for angiography primarily because of post-infarction ischemia. Within the limitations imposed by the patient selection process, it is concluded that well developed coronary collateral vessels are rarely present at the time of infarction. After infarction, they develop rapidly and are generally demonstrable within 2 weeks. It may also be inferred that the preservation of ischemic myocardium by well developed coronary collateral vessels at the time of myocardial infarction may be an uncommon occurrence.

Collateral Circulation↗

PubMed1990

Significance of collateral circulation in reversible left ventricular asynergy by nitroglycerin in patients with relatively recent myocardial infarction.

To evaluate the functional role of coronary collateral circulation in reversible asynergy of the left ventricle, cineventriculography was performed before and after the administration of sublingual nitroglycerin in 19 patients with complete occlusion of the proximal part of the left anterior descending coronary artery. In nine patients who had significant collateral circulation to the infarct-related coronary artery (group A), there was significant improvement in both the left ventricular ejection fraction (53% to 60%, p less than 0.05) and regional wall motion in the infarct zone (8% to 18%, p less than 0.01 in the anterolateral area) with administration of nitroglycerin. In contrast, in the remaining 10 patients without significant collateral perfusion (group B), there were no detectable changes in either global function (49% versus 50%) or regional wall motion (6% versus 8% in the anterolateral area) before and after nitroglycerin. Changes in heart rate and left ventricular peak systolic and end-diastolic pressures with nitroglycerin were comparable in both groups. These results suggest that angiographically demonstrable collaterals preserve viable myocardium, which can improve its contraction when the supply-demand relationship is favorably affected because of increased collateral flow and/or more favorable loading conditions produced by nitroglycerin.

Cineradiography↗

PubMed1979

[Chronic occlusion of a renal artery with aneurysms in the para-aortic collateral circulation and multiple aneurysms in both kidneys (author's transl)].

Chronic occlusion of the main renal artery may be followed by the development of a collateral circulation through ureteric and para-aortic arteries, and through lumbar and suprarenal arteries. A patient with occlusion of the left main renal artery is described, who developed a collateral circulation between the common iliac artery and the distal portion of the renal artery. The para-aortic collateral vessel developed one large and several small aneurysms, and there were aneurysms in both kidneys.

Aneurysm↗

PubMed1983

Collateral circulation in hemicentral retinal vein occlusion.

The perchance occurrence of a hemicentral retinal vein occlusion in an eye with a lightly pigmented fundus allowed us the opportunity to observe the development and flow dynamics of collateral circulation. We are able to demonstrate an optic disc collateral draining into a choroidal vein, a finding which to our knowledge had previously only been documented histologically. The collateral circulation developed slowly over many months and was not rapid enough to prevent chronic microcystic macular changes.

Aged↗

PubMed1977

Intrarenal collateral circulation in the pediatric patient.

The presence of an intrarenal collateral circulation in pediatric patients with segmental renal artery stenosis has not been stressed. Three patients demonstrating these collateral pathways are presented. The anatomy, pathogenesis, angiographic features, differential diagnosis, and significance of intrarenal collaterals in infants and children are discussed.

Adolescent↗

PubMed1991

Development of collateral circulation in a replanted rat hindlimb model.

The development of collateral circulation was studied in a replanted rat hindlimb model by use of the hemodynamic techniques of hydrogen washout and laser Doppler capillary perfusion monitoring. Collateral development occurred and provided blood flow whose magnitude increased linearly over time. Twenty-seven percent of preligation blood flow was present at 2 weeks after replantation, 39% at 4 to 5 weeks, and 77% at 8 to 9 weeks by laser Doppler assessment. Laser Doppler correlated more closely with limb survival than did the hydrogen washout technique. Uniform necrosis (eight of eight) occurred after pedicle interruption in the 2-week group. Partial limb survival was noted in five of eight replants at 4 to 5 weeks on transection of the vascular pedicle, while complete survival of all replants (nine of nine) was seen at 8 to 9 weeks.

Animals↗

PubMed1990

Collateral circulation in skeletal muscles: effect of pentoxifylline and torbafylline.

Vascular casts were prepared using Batson Anatomical corrosion compound, from maximally dilated rat tibialis anterior (TA), extensor digitorum longus (EDL) and soleus (SOL) with normal and limited blood supply (unilateral ligation of the common iliac artery). The weight of casts was expressed as a percentage of muscle wet weight. This value was considered representative for the size of the vascular bed. The value was 2.9 +/- 0.12% (mean +/- SEM) in normal TA, 3.37 +/- 0.15% in EDL and 4.8 +/- 0.43% in SOL. The weight of vascular casts decreased in all muscles to 40% of the values found in the contralateral muscles one week after ligation. Five weeks after ligation, it was about 60% of the control values in TA and EDL, and 80% in SOL. Treatment with torbafylline for one week did not change the weight of the vascular casts. After five weeks the size of the vascular bed was back to control values in EDL and SOL, and only 20% lower than control muscles in TA. This could be attributed to improved development of collateral circulation. Treatment with pentoxifylline improved collateral circulation only in SOL.

Animals↗