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Results for “Collateral Circulation”

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At least 577 records · Page 32Linked to original sources
PubMed1991

[Reserve possibilities of creating the routes of collateral circulation in stenosing lesions of major arteries of the head].

The analysis of complex examination of 54 patients with stenosing lesion of the major cephalic arteries by means of Doppler ultrasound, ultrasound scanning, carotid angiography, computerized tomography is presented. The most frequently, two ways of collateral blood flow--via the anterior communicative artery and via the branches of the external carotid artery were revealed. In the first case, ischemia of cerebral tissue is not pronounced, because the anterior communicative artery is functioning in change of a pressure gradient. The second way of collateral blood flow is less reliable, because it is developing slowly and do not provide adequate supply and normal functioning of the nerve cells.

Adult↗
PubMed1984

Scope and limitations of collateral circulation. Presidential address.

The human body, possessing no true end arteries, is capable of furnishing some collateral vessels for any arterial, venous, or lymphatic obstruction. In places, only capillary anastomoses are immediately available and ischemia may be profound. We have learned to support organs like the heart, brain, or liver while small communications enlarge to increase the flow of blood or lymph. Even in the retina, some success has been obtained by retrograde perfusion through the supra-orbital artery. Supplemental flow, ie, blood varying in content or pressure--such as bronchial blood substituting for pulmonary blood--carries some detriment in the form of diminished function or the rupture of thin-walled vessels.

Arterial Occlusive Diseases↗
PubMed2000

Intracoronary collagen: effects on coronary collateral circulation and the role of thromboxane.

This study investigated the effects of intravascular collagen on coronary collateral blood flow. Collateral vessel growth was stimulated in 11 dogs by embolizing the left anterior descending (LAD) coronary artery with a hollow stainless steel plug. Experiments were performed 41 +/- 7 days after coronary embolization when collateral vessels were moderately well developed. Under alpha-chloralose anesthesia, the LAD was cannulated, and retrograde blood flow was used as a measure of collateral flow. Collagen (10-100 microg/kg) injected into the left main coronary artery caused a decrease of coronary collateral blood flow that became maximal at 3 min after injection and subsided within 9 min. At peak effect intracoronary collagen decreased retrograde flow by 53 +/- 6% from 32.7 +/- 8.2 to 16.8 +/- 3.7 ml/min (p < 0.05) with no change in systemic hemodynamics. Selective thromboxane A2 (TxA2)-receptor blockade with SQ30,741 had no effect on collateral blood flow during basal conditions but attenuated the collateral constriction in response to collagen. Thus, after SQ30,741, collagen caused only a nonsignificant decrease retrograde flow from 35.9 +/- 9.0 to 31.7 +/- 9.62 ml/min. The findings indicate that intravascular collagen exerts a potent vasoconstrictor effect on coronary collateral vessels. Attenuation of this response by TxA2-receptor blockade suggests that thromboxane released by activated platelets is the principal mediator of this response.

Animals↗
PubMed1972

Myocardial blood flow in man: effects of coronary collateral circulation and coronary artery bypass surgery.

The effects of coronary artery bypass graft (CAB) and coronary collaterals (CC) on myocardial blood flow (MBF) were studied in 24 patients undergoing 29 CAB's. MBF after CAB was compared to preexisting MBF by intraoperatively injecting (133)xenon via distal CAB with proximal CAB first occluded then open. Pressure gradients across bypassed obstructions were measured. The results were correlated with preoperative coronary arteriograms to determine the effects of CC on MBF and postobstructive perfusion pressures. Mean MBF was increased by CAB from 32+/-6 (se) ml/min per 100 g (CAB occluded) to 118+/-13 ml/min per 100 g (CAB open). The (133)Xe clearance curves with CAB open were resolved into slow (19+/-2 ml/min per 100 g) and rapid (133+/-12 ml/min per 100 g) phases, suggesting that MBF remained heterogeneous after CAB. Vessels with less than 80% stenosis by angiography had pressure gradients less than 20 mm Hg across obstructions, high postobstructive perfusion pressures (75+/-7 mm Hg), and normal MBF (87+/-6 ml/min per 100 g) even with CAB occluded. Vessels with greater than 80% stenosis or total occlusion by angiography had significant pressure gradients with marked reduction of postobstructive MBF. No significant difference in postobstructive MBF was found when vessels with CC (21+/-4 ml/min per 100 g) were compared to those without CC (17+/-4 ml/min per 100 g) (P > 0.4). These studies demonstrate that (a) mean MBF increased 268% after CAB, (b) heterogeneous MBF persisted after CAB, (c) CC were not associated with significant increases in MBF, and (d) vessels with less than 80% stenosis had less than 20 mm Hg gradient with minimal effect on resting MBF.

Adipose Tissue↗