Importance Of Collateral Circulation Research Articles

A rare case of pituitary apoplexy complicated by internal carotid artery occlusion: Severity obscured by primary collaterals

Pituitary apoplexy complicated by internal carotid artery occlusion was encountered in a patient with surprisingly moderate symptoms at presentation. For a short period of watchful waiting, primary collaterals obscured the emergent need for decompressive surgery, which after the sudden onset of neurological deterioration fortunately salvaged imminent cerebral infarction. Although a few similar cases have been described previously, the importance of collateral circulation has been left virtually without comment, while contrasting treatment strategies and high mortality rates suggest further case reports are warranted. Notably, a symptoms-based management seems likely to be insufficient in these rare situations, while our experience indicate early surgery could be judicious to consider. Keywords: Pituitary apoplexy; Internal carotid artery occlusion; Collateral circulation.

The importance of collateral circulation in acute basilar artery occlusion

The importance of collateral circulation in acute basilar artery occlusion

Augmenting Collateral Blood Flow during Ischemic Stroke via Transient Aortic Occlusion

Collateral circulation provides an alternative route for blood flow to reach ischemic tissue during a stroke. Blood flow through the cerebral collaterals is a critical predictor of clinical prognosis after stroke and response to recanalization, but data on collateral dynamics and collateral therapeutics are lacking. Here, we investigate the efficacy of a novel approach to collateral blood flow augmentation to increase collateral circulation by optically recording blood flow in leptomeningeal collaterals in a clinically relevant model of ischemic stroke. Using high-resolution laser speckle contrast imaging (LSCI) during thromboembolic middle cerebral artery occlusion (MCAo), we demonstrate that transiently diverting blood flow from peripheral circulation towards the brain via intra-aortic catheter and balloon induces persistent increases in blood flow through anastomoses between the anterior and middle cerebral arteries. Increased collateral flow restores blood flow in the distal middle cerebral artery segments to baseline levels during aortic occlusion and persists for over 1 hour after removal of the aortic balloon. Given the importance of collateral circulation in predicting stroke outcome and response to treatment, and the potential of collateral flow augmentation as an adjuvant or stand-alone therapy for acute ischemic stroke, this data provide support for further development and translation of collateral therapeutics including transient aortic occlusion.

Invited commentary

Invited commentary

Importance of collateral circulation in coronary heart disease

Collateral arteries are a common but inconsistent finding in coronary heart disease (CHD). We endeavoured to review the methods for coronary artery collateral assessment, the predictors and clinical importance of collateral blood flow, and the potential for therapeutic augmentation of collateral anastomoses. While many methods have been used to assess collateral blood flow only a few have been formally validated. Collateral flow index, as determined by measurement of intra-coronary pressure or flow velocity, is the most robust measure of collateral flow. These techniques have led to important advances in our understanding of collateral artery function. Coronary collateral arteries may prevent myocardial ischaemia in healthy subjects and in patients with CHD. A functional collateral circulation may lead to reduced ischaemia, preservation of ventricular function, and an improved prognosis. Recent trials have demonstrated that vascular progenitor cell therapies may improve ventricular function following acute myocardial infarction, raising the possibility of effective biological treatments to improve myocardial blood flow and prognosis in CHD. Coronary collateral anastomoses represent a prognostically important adaptive response in patients with CHD. Therapeutic augmentation of collaterals with emerging biological therapies represents a desirable goal for treating CHD patients.

Importance of Collateral Circulation in the Vascularly Occluded Feline Intestine

The aim of this study was to assess the extent of collateral blood flow provided by the celiac and inferior mesenteric arteries to the intestines during total occlusion of the superior mesenteric artery (SMA). In anesthetized cats, blood flow to the pancreas, duodenum, jejunum, ileum, and colon was measured with radioactive micropheres (15 microns in diameter) before and during occlusion of the SMA. Superior mesenteric artery occlusion significantly decreased (by 63%) blood flow to the head of the pancreas. Flow to the neck and tail of the pancreas was not altered. Blood flow to the proximal and distal duodenum was significantly reduced by 35% and 61%, respectively. Along the entire jejunum and ileum, SMA occlusion markedly decreased blood flow by an average of 71%. In the proximal colon, blood flow decreased by 63%, whereas flow to the middle and distal colon was not affected by SMA occlusion. Reduction in total wall blood flow to the small and large intestines was largely due to a marked reduction in mucosa/submucosa blood flow; muscularis/serosa flow was not affected. The results of this study suggest that total occlusion of the SMA does not compromise blood flow to the neck and tail of the pancreas and middle and distal colon (tissues that are normally perfused with blood from either the celiac or inferior mesenteric arteries). Perfusion through collaterals maintains flow to the head of the pancreas and gut (from duodenum to proximal colon) to within 30%-65% of control (preocclusion) flow. An important new observation of this study is that collateral blood vessels are much more effective in preventing ischemia in the muscularis/serosa than in the mucosa/submucosa after SMA occlusion.

Surgical treatment of cerebrovascular disease.

Several new concepts of surgical management of cerebrovascular insufficiency due to extracranial arterial occlusive disease have been developed since the first corrective procedure was done in 1953. The concept of the totality of cerebral blood flow, the importance of collateral circulation, and the recognition of intracranial arterial patterns are discussed and illustrated in several case reports.

POLAROGRAPHIC STUDY OF CEREBRAL COLLATERAL CIRCULATION

THE IMPORTANCE of collateral circulation in the brain has been evident since the observations of Astley Cooper on ligation of the common carotid artery in man1and ligation of the principal cerebral vessels in the dog.2 It is also common neurological experience that there is considerable variation in capacity for adjustments in the cerebral circulation from one person to another, for carotid occlusion in one person may occur without symptoms, whereas the infarction of most of a cerebral hemisphere may follow in another. The anatomical explanation for this is, in part, the variation in size of the communicating arteries of the circle of Willis. Such variation of collateral circulation prompts the neurosurgeon to compress the carotid artery preoperatively as a test of collateral circulation before ligating this vessel. Recent experience with arteriography has shown that some persons may successfully survive for years without either one or the other