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PubMed1985

Effect of halothane on coronary collateral circulation.

The authors studied the effect of halothane in a canine model of coronary collateral circulation secondary to chronic occlusion of a coronary artery. Two sets of experiments were performed. In the first experiments, Ameroid constrictors were placed around the left anterior descending coronary artery to produce complete occlusion in three weeks. An inflatable occluder was placed around the circumflex coronary artery in order to apply a mild stenosis to the artery supplying the collateral vessels to produce vasodilation distal to the stenosis. Regional myocardial blood flows were measured using radioactive microspheres. Blood flows to normal and collateralized myocardium were decreased significantly during halothane anesthesia, but perfusion of the subendocardium in both regions was maintained even in the presence of mild stenosis of the circumflex coronary artery supplying the collateral vessels, as indicated by unchanged endocardial/epicardial blood flow ratios. In the second experiments, chronic occlusions of both circumflex and right coronary arteries were produced using Ameroid constrictors. In these animals, sedated using xylazine, pacing-induced tachycardia produced a marked but reversible decrease in blood flow to the collateralized subendocardium. During halothane anesthesia at normal heart rate, blood flow to the collateralized subendocardium was well maintained, but tachycardia produced marked decrease in blood flow to the collateralized subendocardium, leading to the demise of four of seven dogs. The authors conclude that in this chronic canine model, in which control measurements were made during sedation using xylazine, coronary collateral blood flow is well maintained during halothane anesthesia at normal heart rate, but tachycardia during halothane anesthesia severely limits blood flow to the collateralized subendocardium.

Animals↗
PubMed1989

Coronary collateral circulation: clinical significance and influence on survival in patients with coronary artery occlusion.

In a consecutive series of 96 patients with coronary artery occlusion, 67 had good and 29 had no or poor collateral circulation. Patients with good collaterals had the severest degree of coronary artery disease. Good collaterals are associated with a higher incidence of angina pectoris and normal electrocardiogram and with lower incidence of Q-waves, positive exercise tests, heart failure, previous myocardial infarction, and dyskinesia at ventriculography. Survival rates after 10 years were (1) 51.5% with good and 34.5% with poor collaterals (p less than 0.1), (2) 59.4% with angina pectoris and good collaterals and 41.2% with angina pectoris and poor collaterals (p less than 0.05), (3) 64.8% without and 24.4% with heart failure and good collaterals (p less than 0.001), and (4) 58.3% without and 16.1% with heart failure and poor collaterals (p less than 0.01). Good collaterals protect the myocardium by prevention of acute myocardial infarction and heart failure and thus improve survival.

Angina Pectoris↗
PubMed2006

Coronary collateral circulation: the effects of smoking and alcohol.

OBJECTIVE: The presence or absence of coronary collaterals is of vital importance during acute ischemia. Smoking and alcohol have been suggested to play a role, but data are scarce. We examined the extent to which smoking and alcohol use affect the presence of coronary collateral circulation. METHODS: Cross-sectional study in 242 patients, admitted for elective PTCA. Smoking was defined as past or current. Pack years were calculated and categorized into never-smokers (reference-category): <10, 10-19, 20-29, and >or=30 pack years. Alcohol consumption was defined as past or current, and categorized into never-users (reference-category): <1, 1-10, 11-20, and >or=21 units per week (UPW). Collaterals were graded with Rentrop's classification. Coronary collateral presence was defined as Rentrop-grade >or=1. RESULTS: Current smoking (odds ratio (OR) 4.17; 95% confidence interval (CI) 1.79-9.71) was positively associated, while pack years of smoking was not related. Current alcohol intake showed a J-shaped tendency with coronary collateral presence, while past moderate alcohol consumption was inversely associated (OR 0.19; 95% CI 0.04-0.98). CONCLUSIONS: Smoking and (to some extent) alcohol use are associated with collateral presence. The results support the view that life-style factors may affect the formation of coronary collaterals in patients with ischemic cardiac disease.

Aged↗
PubMed1996

[Evaluation of ischemic preconditioning on collateral circulation, ventricular function and clinical outcome in acute myocardial infarction].

PURPOSE: To evaluate the influence of ischemic preconditioning (IP) in collateral circulation (CC), early ventricular function and in hospital outcomes after myocardial infarction (MI). METHODS: We studied 97 patients with a 1st anterior MI within 6h of pain and isolated total proximal occlusion of the left anterior descending artery, divided in 2 groups: with (GA) or without (GB) angina before MI. Coronariography and ventriculography were performed prior to reperfusion. The left ventricular (LV) ejection fraction was measured by the area length method and anterior wall motion by the centerline method. RESULTS: There was no difference between the two groups in sex, age, CKMB level, treatment, reperfusion rate. Global LV ejection fraction and anterior wall motion were similar, respectively, 39 +/- 9% and -2.55 +/- 1.17 SD/chord for GA and 37 +/- 8% and -2.75 +/- 0.79 and -2.75 +/- 0.79 SD/chord for GB (p = ns). The incidence of visible CC to the infarct area was also similar (present in 6 GA vs 8 GB patients). However, GA patients fared significantly better during hospitalization: No GA patient presented Killip class > or = 2 compared to 8 GB patients (p = 0.007). CONCLUSION: Although collateral coronary circulation grades, global and regional LV function were similar between the two groups, the presence of angina pectoris preceding an acute myocardial infarction was associated with a better in hospital evolution, what could be partially explained by preconditioning phoenomena.

Collateral Circulation↗
PubMed1986

The response of the coronary collateral circulation to acute administration of nifedipine: an angiographic and ergometric study.

To evaluate the role of collaterals in patients with effort angina we retrospectively compared the coronary cineangiograms of 14 subjects ("responders") who improved their exercise tolerance after acute nifedipine therapy with 14 subjects ("non-responders") with the same symptomatology who did not respond to the same treatment. The status of collaterals was graded with a score from a minimum of 0 to a maximum of 5. The responders showed a greater score than the non-responders (3 +/- 1 vs. 1 +/- 1, P less than 0.001), whereas there was no difference in the number of stenosed vessels between the two groups (1.8 +/- 0.9 vs. 2 +/- 0.8). Thus, in patients with effort angina and critical coronary stenosis, the presence of an efficient coronary collateral circulation can favour the increase in coronary flow reserve after vasodilator therapy. Our results suggest that the grading of collaterals may add useful information to the simple classification of one-, two- or three-vessel coronary artery disease.

Adult↗
PubMed1972

Functional development of the coronary collateral circulation during coronary artery occlusion in the conscious dog.

We studied changes in the coronary collateral circulation during coronary artery occlusion in 14 conscious dogs by: a) determining simultaneous changes in peripheral coronary pressure (PCP) and retrograde flow (RF) after abrupt coronary artery occlusion; b) correlating these functional indices with quantitative anatomic indices (AI) of coronary collateral development (Menick et al: Am Heart J 82:503-510, 1971); and c) observing changes in these indices after repeated reocclusions of a coronary artery. These dogs were subjected to left circumflex coronary artery (LCCA) occlusions for 2 hours to 8 days; pressure tubes were implanted in the aorta and LCCA, the latter tube placed distal to an occlusive cuff for PCP and RF measurements. Afterwards the animals were sacrificed, their hearts injected with a modified Schlesinger's gelatin mass, and AI determined. During 2 to 24 hour LCCA occlusions (11 dogs) mean PCP rose to levels 50 to 80% of prevailing aortic pressure. During repreated 2- to 24-hour occlusions (2 dogs) in the same dog, the rate at which PCP rose increased. Retrograde flow was unchanged during 2- to 24-hour occlusions. Anatomic indices of these dogs were in the same range as those observed in unoccluded controls. When LCCA occlusion was maintained for more than 4 days (3 dogs), mean PCP rose during the first 24 hours and then remained stable; RF did not change until 4 days into occlusion and then increased. Anatomic indices of dogs occluded for more than 4 days were significantly greater (P < 0.001) than those of the 2- to 24-hour occlusion groups. Our study shows that: a) the early PCP rise after occlusion is not associated with an increase in RF, b) RF is a better index of collateral function and c) RF correlated well with the anatomic development of the collateral bed.

Animals↗
PubMed1987

Importance of coronary collateral circulation for kinetics of serum creatine kinase in acute myocardial infarction.

The effect of coronary collateral perfusion on the kinetics of creatine kinase (CK) was examined in 32 patients undergoing intracoronary thrombolysis within 6 hours after the onset of a first acute myocardial infarction (AMI). Blood sampling for CK was performed every 2 to 4 hours for a period of 72 hours after AMI. The cumulative CK release was determined using the integrated appearance function curve with the individual disappearance rate. In 19 patients in whom thrombolysis was successful (group A), time to peak CK level was 11 +/- 1 (standard error of the mean) hours after AMI and cumulative CK release was 2,599 +/- 424 U/liter. In 6 patients who had a significant collateral circulation to the infarct-related coronary artery and unsuccessful reperfusion (group B), the time to peak CK was 16 +/- 1 hours (p less than 0.05 compared with group A) and cumulative CK release was 1,897 +/- 478 U/liter (difference not significant compared with group A). In the remaining 7 patients, with neither recanalization nor significant collateral perfusion group C, time to peak CK was 21 +/- 1 hours and significantly (p less than 0.05) longer than groups A and B. Cumulative CK release (2,707 +/- 776 U/liter) was not significantly different from groups A and B. Thus, collateral perfusion is an important determinant of the CK time-activity curve during AMI. Early peaking of CK levels does not reliably identify spontaneous or drug-induced recanalization of the infarct-related coronary artery.

Collateral Circulation↗
PubMed1975

Fate of coronary collateral circulation after aorto-coronary saphenous vein bypass grafts.

The pre- and postoperative patterns of coronary artery collateral circulation have been studied in 34 patients who had saphenous vein bypass grafting. When the graft remained patent homocoronary collaterals could not be visualized after operation, but new intercoronary anastomoses frequently developed to other diseased arteries. When the graft and the bypassed artery were both obstructed there was a high incidence (5 out of 11) of myocardial infarction despite good preoperative collaterals.

Aorta, Thoracic↗
PubMed1988

Transcranial Doppler ultrasonography of carotid-basilar collateral circulation in subclavian steal.

The combination of a carotid-basilar and a vertebro-vertebral collateral circulation was verified directly in a patient with a complete subclavian steal by means of transcranial Doppler ultrasonography. The patient showed permanently reversed blood flow in the basilar artery. The subclavian steal influenced the hemodynamics of the circle of Willis at rest and during functional tests of the collaterally supplied arm. Our investigation provides the first direct experimental evidence of increased blood flow velocity in the carotid artery after decompressing the collaterally supplied arm.

Arm↗
PubMed1979

Effects of theo-esberiven on the development of collateral circulation in dog hearts.

Effects of Theo-Esberiven, a coronary vasodilator, on the development of collateral circulation were investigated in dogs with their left anterior descending artery chronically occluded. The drug was administered i.v. at 0.1 ml/kg once a day for 1 to 4 weeks after the occlusion. Left circumflex coronary flow in dogs treated with the drug was increased over the value in control ones when measured one week after the occlusion. At the same time, the ratio of retrograde pressure to perfusion pressure, which correlates negatively with the collateral vascular resistance, significantly exceeded the value in control (P less than 0.05). On the basis of observations with blood vessel casts of hearts, distinct anastomoses between the circumflex and anterior descending arteries had already been observed in all preparations from dogs treated for 2 weeks in contrast to the findings seen in control ones. There were less histological changes in myocardial tissue obtained from dogs treated for one week than those in control ones. From these results, Theo-Esberiven appears possibly to accerelate the collateral development at the earlier stages after the coronary occlusion.

Aminophylline↗
PubMed1995

Sympathetic influences on the native canine coronary collateral circulation.

OBJECTIVE: The aim was to investigate the influence of the sympathetic nervous system on the native collateral circulation in the intact heart. METHODS: Experiments were performed on 10 open chest dogs anaesthetised with alpha chloralose. The left anterior descending coronary artery was cannulated and embolised with 25 microns microspheres. Collateral resistance was determined from measurements of aortic pressure and retrograde flow. Additional haemodynamic measurements included left ventricular pressure and blood flow in the circumflex coronary artery. RESULTS: Coronary embolisation decreased retrograde resistance from 41.5(SEM 6.0) to 20.1(1.9) mm Hg.ml-1.min-1 (P < 0.01). Left stellate stimulation for 60 s (10 Hz) significantly increased circumflex blood flow and decreased circumflex resistance from 2.1(0.3) to 1.6(0.2) mm Hg.ml-1.min-1. Retrograde resistance during sympathetic stimulation decreased from 19.7(1.8) mm Hg.ml-1.min-1 (P < 0.01). Transient occlusion of descending aorta resulted in changes in perfusion pressure and retrograde flow that were similar to those observed during stellate stimulation. Stellate stimulation after beta blockade with timolol (0.1 mg.kg-1) increased circumflex resistance from 1.9(0.2) to 2.3(0.3) mm Hg.ml-1.min-1 (P < 0.01) but did not alter retrograde resistance. CONCLUSIONS: The sympathetic nervous system does not have a direct effect on native coronary collateral vessels. Increased sympathetic input to the heart does not result in a coronary steal phenomenon. The primary determinant of flow and resistance in the native collateral network during sympathetic activation is the arterial perfusion pressure.

Animals↗
PubMed1989

Importance of collateral circulation for prevention of left ventricular aneurysm formation in acute myocardial infarction.

The effect of preexistent coronary collateral perfusion on the prevention of left ventricular aneurysm formation was examined in 47 patients undergoing an intracoronary thrombolysis within 6 hours after the onset of a first acute anterior myocardial infarction. Left ventricular aneurysm formation and wall motion were analyzed with cineventriculography. A left ventricular aneurysm was determined as well-defined demarcation of the infarcted segment from normally contracting myocardium. In 25 patients with successful thrombolysis (group A), a left ventricular aneurysm was observed in one patient (4%) during the chronic stage of infarction. In 10 patients who had a significant collateral circulation to the infarct-related coronary artery and unsuccessful reperfusion (group B), the left ventricular aneurysm was observed in only one patient (10%). In the remaining 12 patients with unsuccessful recanalization in the absence of a significant collateral perfusion (group C), there was a higher incidence (seven of 12, 58%) of left ventricular aneurysm formation than in groups A and B (p less than 0.05). In group A, both the global ejection fraction and regional wall motion in the infarct areas improved significantly (p less than 0.05) between the acute and chronic stages of infarction. By contrast, in groups B and C, these indexes on the ventricular function did not change significantly during the convalescent period. Thus, although the collateral perfusion existing at the onset of acute myocardial infarction may not improve ventricular function, it exerts a beneficial effect on the prevention of left ventricular aneurysm formation.

Adult↗
PubMed1986

Significance of collateral circulation on peri-infarct zone: assessment with stress thallium-201 scintigraphy.

To evaluate the significance of collateral circulation on peri-infarct zone, stress myocardial scintigraphy and contrast left ventriculography (LVG) were performed in 38 patients with recent myocardial infarction (MI). All patients had at least one completely occluded coronary artery corresponding to the infarct area. In patients with good collaterals, stress induced transient enlargement of the perfusion defect, however, in those with poor or no collaterals the enlargement did not occur (p less than 0.05). Wall motion abnormality on LVG was significantly milder in the former patients than in the latter (p less than 0.001). Transient enlargement of the perfusion defect after stress and milder left ventricular asynergy were more frequently observed in patients with anterior MI and good collaterals. These observations indicate that good collaterals may keep some myocardium in the peri-infarct zone viable.

Adult↗