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PubMed1991

Collateral circulation as a marker of the presence of viable myocardium in patients with recent myocardial infarction.

The relationship between the presence of viable myocardium and the extent of coronary collateral circulation to the infarct area was evaluated in 20 patients with a recent anterior myocardial infarction who had complete obstruction of the left anterior descending coronary artery. The viability of myocardial tissue was assessed by exercise thallium-201 myocardial scintigraphy, and the collateral circulation was angiographically evaluated by means of a collateral index ranging from 0 to 3. Patients were divided into two groups according to the presence (group 1, n = 10) or absence (group 2, n = 10) of viable myocardium in the perfusion territory of the infarct-related artery. The collateral index in group 1 was 2.5 +/- 0.5 (SD), which was significantly higher than the 0.7 +/- 0.8 in group 2. These findings indicate that the presence of ischemic but viable myocardium is intimately related to the development of collateral circulation in patients with myocardial infarction, and the existence of well-developed collateral channels predicts the presence of viable myocardium in the infarct area.

Collateral Circulation↗
PubMed1992

Relationship between the preexistent coronary collateral circulation and successful intracoronary thrombolysis for acute myocardial infarction.

The purpose of this study was to evaluate whether the existence of coronary collateral circulation influences recanalization rates of intracoronary thrombolysis. The study population consisted of 85 consecutive patients undergoing intracoronary thrombolysis within 6 hours after the onset of the first acute myocardial infarction, all of whom had a complete occlusion of the infarct-related coronary artery. Intracoronary thrombolysis with high-dose urokinase (960,000 IU) was attempted at a rate of 24,000 IU/min. Of 18 patients (group A) who had good angiographic collateral circulation to the area perfused by the infarct-related coronary artery, the obstructed artery was recanalized to a residual luminal diameter stenosis of less than or equal to 90% (successful recanalization) in only five (28%). In contrast, of 67 patients (group B) with poor or no collateral circulation, recanalization was successful in 40 (60%) (p less than 0.05). Antegrade flow of infarct-related arteries was observed following thrombolysis in 12 (67%) of 18 group A patients and in 56 (84%) of 67 group B patients (p = NS). It was concluded that (1) the presence of collaterals correlates with the presence of high-grade stenosis; (2) the presence of collaterals correlates with the presence of high-grade stenosis; (2) the presence of collaterals is inversely related to the efficacy of thrombolytic therapy; and (3) the difference in successful recanalization rates observed between the two groups probably reflects the impact of underlying stenosis severity on the effectiveness of lytic therapy.

Adult↗
PubMed1987

Ischaemia induced development of functional coronary collateral circulation in ponies.

The response of coronary collaterals in nine ponies subjected to repeated reversible occlusions (2 min duration, 30 min interval) of the left anterior descending coronary artery was studied at rest. Each pony was instrumented with a Doppler flowmeter and hydraulic cuff occluder around the left anterior descending coronary artery, left ventricular subendocardial sonomicrometers, and a left ventricular micromanometer. Initial occlusions increased end diastolic myocardial segment length by 3% and decreased segment systolic shortening, stroke work, and velocity of shortening by 103%, 95%, and 79% respectively in the left ventricular apex. Left ventricular systolic and end diastolic pressure, peak positive dP/dt, and heart rate were not significantly changed by occlusion. After 421(70) (mean(SEM)) occlusions no sustained alterations in myocardial segment function occurred in response to occlusion. Thus the presence of a subendocardial plexus did not protect against a severe loss of myocardial segment function when the ponies were initially subjected to occlusions of the left anterior descending coronary artery. However, repeated reversible occlusions enhanced coronary collateral blood flow such that it was adequate to maintain left ventricular function in the absence of left anterior descending coronary artery flow. It is concluded that the pony is highly suitable for use in studies of coronary collateral circulation because of its coronary anatomical similarity to man and its capacity to develop functional collateralisation.

Animals↗
PubMed1990

Improvement of ST segment depression by gradual recruitment of collateral circulation.

The purpose of the present study was to document that the coronary collateral vessels do not open immediately upon the occurrence of myocardial ischemia. A multistage bicycle exercise was performed to determine a maximal tolerable work load until the onset of angina and significant ST segment depression in 10 patients with well-developed collateral circulation. On a different day, exercise with the maximal tolerable work load was repeated for a comparable exercise duration. In 2 of the 10 patients, anginal pain was gradually alleviated despite the continuation of exercise with fixed work load. The extent of ST segment depression at 3 min of exercise with fixed work load was 0.20 +/- 0.10 (SD) mV, significantly (p less than 0.05) greater than 0.16 +/- 0.08 mV at the end of exercise with fixed work load. In contrast, the rate-pressure product was smaller at 3 min than at the end of exercise with fixed work load (20,900 +/- 5,500 vs. 22,700 +/- 5,700 mm Hg.beats/min; p less than 0.05). In 5 patients without well-developed collateral circulation, the extent of ST depression changed in parallel with changes in rate-pressure product during exercise with fixed work load. Thus, it is concluded that the delayed collateral opening plays a critical role in the pathogenesis of myocardial ischemia in patients with a totally occluded coronary artery.

Adult↗
PubMed1990

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↗
PubMed1986

[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↗
PubMed1987

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↗
PubMed1990

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↗
PubMed1977

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↗
PubMed1991

[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↗
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↗
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↗
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↗