The present study was performed to examine the mechanism by which cyclooxygenase blockade produces vasoconstriction in well-developed coronary collateral vessels. Eight dogs were studied 4 to 6 months after occlusion of the left anterior descending coronary artery (LAD) had been performed to stimulate collateral vessel growth. At the time of study, the LAD was cannulated at the site of occlusio...

Objective: Collateral circulation is essential for cerebral perfusion and the maintenance of metabolism function. The clinical factors affecting collateral in brain still unknown. In presence slowly developing stenosis, decrease blood flow can be compensated by adequate circulation, signs hemodynamic deterioration may not observed. Case: This case with a 6-year retrospective record only right I...

Natural adaptation to femoral artery occlusion in animals by collateral artery growth restores only approximately 35% of adenosine-recruitable maximal conductance (C(max)) probably because initially elevated fluid shear stress (FSS) quickly normalizes. We tested the hypothesis whether this deficit can be mended by artificially increasing FSS or whether anatomical restraints prevent complete res...

In patients with high-grade atherosclerotic stenosis or occlusion of the extracranial cerebral arteries, subarachnoid hemorrhage (SAH) may occur, potentially due to rupture of fragile dilated pial collateral vessels. This association has been well described in Moyamoya disease. There are only few cases in the literature that reported SAH due to bilateral carotid artery stenosis but intraventric...

BACKGROUND Our study compares the effect of acute proximal stenosis of a coronary artery supplying a myocardial perfusion bed with that of stenosis of an adjacent artery resulting in collateral flow diversion supplied by the same perfusion bed. These alterations in coronary physiology were quantified by digital angiographic impulse response analysis of contrast material mean transit time for th...

BACKGROUND The Circle of Willis (CoW) is the most important collateral pathway of the cerebral artery. The present study aims to investigate the collateral capacity of CoW with anatomical variation when unilateral internalcarotid artery (ICA) is occluded. METHODS Basing on MRI data, we have reconstructed eight 3D models with variations in the posterior circulation of the CoW and set four diff...

BACKGROUND AND PURPOSE We correlated the mean transcranial Doppler blood flow velocity (FVm) during carotid endarterectomy with the functional collateral pathway(s) documented by angiography. METHODS Three patient groups were established: group 1 was dependent on the anterior communicating artery, group 2 on the anterior communicating artery and ipsilateral posterior communicating artery, and...

BACKGROUND AND PURPOSE Radial head fractures are common, and may be associated with other injuries of clinical importance. We present the results of a standard additional MRI scan for patients with a radial head fracture. PATIENTS AND METHODS 44 patients (mean age 47 years) with 46 radial head fractures underwent MRI. 17 elbows had a Mason type-I fracture, 23 a Mason type-II fracture, and 6 e...

PURPOSE To determine the accuracy of transcranial Doppler (TCD) ultrasound for evaluation of collateral supply through the circle of Willis in patients with internal carotid artery (ICA) occlusion. METHODS The evaluation of the collateral pathways through the circle of Willis with TCD ultrasound and with cerebral angiography was compared in 40 patients (30 men, 10 women; mean age, 55 +/- 9 ye...

The human coronary collateral circulation is prognostically relevant. The understanding of collateral formation and its determinants may guide future therapeutic strategies aiming at promoting collateral growth and functionality, and hence reducing the global burden of coronary artery disease (CAD).