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At least 1,441 records · Page 80Linked to original sources
PubMed2000

Immediate changes of collateral function after successful recanalization of chronic total coronary occlusions.

BACKGROUND: Coronary collaterals are essential to maintain myocardial function in chronic total coronary occlusions (TCOs). The aim of the present study was to assess the collateral circulation in TCOs before coronary angioplasty and to determine the recruitable collateral perfusion after recanalization by use of intracoronary Doppler flow velocimetry. METHODS AND RESULTS: In 21 patients with TCOs (duration >4 weeks), Doppler recordings of basal collateral flow were obtained before the first balloon inflation. Angioplasty was performed with stent implantation in all lesions. At the end of the procedure, recruitable collateral flow was measured during a repeat balloon inflation. The collateral flow index (CFI) was calculated from the velocity integral during the occlusion/velocity integral of antegrade flow. In 17 of 21 patients, angiography was repeated after 24 hours, and CFI was reassessed. Average peak velocity of collateral flow was 10.9+/-5.6 cm/s with a predominantly systolic flow (diastolic/systolic velocity ratio <0.5) compared with antegrade flow (diastolic/systolic velocity ratio >1.5). After recanalization, the average peak velocity of recruitable collateral flow dropped by >50% to 4.7+/-2.5 cm/s. CFI fell from 0.48+/-0.25 to 0.21+/-0.16 (P:<0.001). There was no further change of CFI during the following 24 hours. CFI was higher in patients with preserved regional ventricular function than in those with akinetic myocardium (0.57+/-0.23 versus 0.38+/-0.12, P:<0.05). CONCLUSIONS: Collateral circulation in TCO provided 50% of antegrade coronary flow. A considerable fraction of collateral flow was immediately lost after recanalization, indicating that TCO may not remain protected from future ischemic events by a well-developed collateral function.

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PubMed1988

[Characteristics of extrahepatic collateral blood flow in patients with cirrhosis of the liver].

Percutaneous transhepatic portography was performed in 120 patients with cirrhosis of the liver with the intrahepatic form of pleural hypertension. It was shown that the degree of portal hypertension was associated with the presence of collateral circulation rather than with its distribution. The preferable way of collateral shunt is thought to be the gastroesophageal anastomosis which is not however hemodynamically effective. The results obtained show that natural collateral circulation is not able to provide decompression of the portal system.

Collateral Circulation↗
PubMed2003

[Specific features of circulation in aorto-iliac arterial occlusion].

On occlusion of aorto-iliac segment arteries the collateral circulation ensures an effective compensation of circulation in lower extremities and pelvic organs. The Doppler characteristics of the circulation in visceral and collateral ways of circulation are the subject of the study. The power of ultrasound duplex scanning to evaluate the regional hemodynamics on atherosclerotic occlusion of aorto-iliac segment vessels has been proved. The Doppler parameters of circulation in upper (UMA) and lower (LMA) mesenteric arteries and internal iliac artery (IIA) on high, moderate an low occlusion of abdominal part of aorta (APA) and on unilateral occlusion of iliac arteries have studied. Depending on the level and grade of extension of occlusion of main arteries the collateral circulation may increase in two or three times. Comparing volumetric velocity of circulation (VVC) in UMA and LMA in control group and in patients with low occlusion of APA an increase of VVC in the artery that has an opening situated directly near the proximal site of occlusion were revealed. These results are the evidence of functional remodelling of regional hemodynamics and of the presence of resources of collateral circulation on occlusional and stenothic lesion of aorto-iliac segment arteries.

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PubMedDate not supplied

[Effect of nonachlazine on systemic hemodynamics and the collateral coronary circulation in acute myocardial ischemia].

Systemic hemodynamics (thermodilution), retrograde coronary blood flow, oxygen tension and bioelectric activity of the myocardium were examined in dog experiments to show that nonachlazin produces an intensive and long-lasting increase in the collateral blood flow to the zone of acute myocardial ischemia and in the pressure in the ligated venous artery. Concurrently it elevates oxygen tension in the affected part of the heart. The cardiostimulant effect of the drug was associated with augmentation of the heart volume on account of an elevated stroke output in the presence of diminished general peripheral vascular resistance.

Acute Disease↗
PubMed1977

Importance of the external carotid artery in extracranial cerebrovascular occlusive disease.

We have encountered 12 patients whose symptoms of transient ischemic attacks were due to total occlusion of the internal carotid artery with patency of the intracranial circulation being maintained by collateral circulation from the external carotid artery. In each case there was either tight stenosis or total occlusion at the origin of the external carotid artery. Eleven of the 12 patients were operated upon, receiving either thromboendarterectomy of the external carotid artery or a saphenous vein bypass to the patent distal portion of this artery. Ten of these 11 had complete or significant relief of symptoms. Although this condition represents only a small percentage of the total number of clinically significant extracranial occlusive lesions, studies suggest that the external carotid artery may be involved more commonly than previously suspected. Adequate radiographic visualization of the cerebral circulation is essential to evaluate the collateral pathways.

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PubMed1986

The pig as a model for myocardial ischemia and exercise.

The pig has been well characterized as an appropriate model for the study of coronary physiology, the coronary collateral circulation and exercise physiology. We compared both Yucatan miniature swine and young farm pigs in experiments involving myocardial ischemia, infarction and exercise. The Yucatan pig was vigorous, docile and proved to be an appropriate model of coronary physiology and exercise in man. The exercise capacity of the Yucatan pig was greater than that of the similar weight Hampshire pig, apparently because of the higher hematocrit and larger heart size. Both breeds were able to increase their maximal oxygen consumption (VO2 max) by approximately 25% after 10 weeks of training. Experiments measuring maximal coronary capacity suggest that the vascular capacity was similar to that of man, but less than that of the dog. Acute occlusion of the coronary artery in pigs infarcted most of the tissue of the vascular bed at risk. The collateral circulation of the pig is less than one fourth that of the dog and is similar to that of man. Slow occlusion of the left circumflex coronary artery produces an ischemic vascular bed which is collaterally dependent with only 5% infarction. Collateral flow is sufficient to meet resting conditions, but during exercise, severe ischemia is unmasked. This ischemia is present for up to 16 weeks following occlusion. The observation of limited infarction in conjunction with limited collateral vessel development suggests that this is a good model for investigating the growth and development of coronary collateral circulation in man.

Animals↗
PubMed1998

[Quantification of myocardial ischemia in regions dependent on occluded coronary arteries in patients without previous infarction].

INTRODUCTION AND OBJECTIVES: The aim of this study is to assess myocardial ischemia in regions with no infarction dependent occluded coronary arteries. PATIENTS AND METHODS: 149 patients with proved coronary artery disease and without previous myocardial infarction were studied by 99mTc-MIBI SPECT (long protocol) and coronary angiography. The extent of the uptake reversibility was quantified in 3 regions (antero-septal, inferior and lateral) of the polar maps, assessing the percentage of each region that had a > 10% difference resulting from the rest uptake minus the stress uptake. The regions dependent on one occluded artery were compared to those dependent on non-occluded arteries. In the regions dependent on one occluded artery a comparison was also made between those which had a good collateral circulation and those which did not. RESULTS: Fifty-four out of 149 patients (36%) had at least one occluded coronary artery (20 anterior descending, 22 right and 27 circumflex coronary arteries). In the visual analysis, reversible defects were observed in all patients with occlusion of the anterior descending and the right coronary artery, but only in half of the occlusions of the circumflex coronary artery. The extent of this reversibility was significantly higher in the regions dependent on occluded arteries and was highly variable, though lower when good collateral circulation was present. CONCLUSIONS: Reversible defects were always observed in the occlusions of the left anterior descending and right coronary arteries, but only in half of those of the circumflex artery. The extent of the ischemia was higher in the regions dependent on one occluded coronary artery, mainly when there was an absence of good collateral circulation.

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PubMed2006

Effects of coronary collateral vessels in left ventricular segmental motions and myocardial viability using color kinesis dobutamine stress echocardiography.

OBJECTIVE: To detect the functional importance of coronary collaterals, which develop after acute myocardial infarctions (AMI). METHODS: Forty patients with acute AMI whose coronary angiography demonstrated a total occlusion of the left anterior descendant (LAD) artery were included in the study, between January 2003 and June 2004. All of the study patients underwent coronary angiography and left ventriculography using standard Judkins techniques (Phillips Integris-3000). Left ventricular (LV) free walls were divided into 5 segments, and all of these segments motions were evaluated then LV free wall motion score index (WMSI) was calculated. The study patients were divided into 2 groups: good (Rentrop 3; group I; n = 14) and poor coronary collateral circulation (Rentrop 0-2; group II; n = 26) according to the Rentrop grading. Then, color kinesis dobutamine stress echocardiography (CK-DSE) was performed to all patients with standard techniques 6 weeks after AMI. RESULTS: There were no significant differences for age, gender, risk factors for the coronary artery disease and use of the fibrinolytic therapy between the groups. There were no significant statistical differences for angiographic WMSI, left ventricular ejection fraction (LVEF), end-diastolic volume, end-systolic volume and end-diastolic pressures between the 2 groups. No difference was detected between Group I and II for initial EF, WMSI and peak dose WMSI in CK-DSE procedure. Viability was determined in all of the 14 patients in group I (100%) and 12 of 26 patients in group II (46%) (p = 0.03). CONCLUSION: In early periods of an AMI genesis of the coronary collateral circulation does not affect left ventricular global and regional systolic functions, but increase viability quite significantly. According to our findings early revascularization could be carried out in patients with good coronary collateral circulation without doing any test for viability.

Cardiotonic Agents↗