Improvement of cerebral circulation by extracorporal collateral between the femoral and the external carotid artery in experimentally induced ischaemia.
ABSTRACT The purpose of this study was to examine the effect of extracorporal collateral circulation (ECCC) between the femoral and the external artery (ECA) on the cerebral circulation, in experimentally induced ischaemia, in rabbits. The animals were divided in four groups. Seven animals (Group A) were used to determine the injection pressure (150-160 mmHg) at the ECA, necessary to achieve collateral circulation between ECA and internal carotid artery (ICA), after occlusion of ICA. Group B (8 rabbits) was the control group for establishing cerebral ischaemia (CI) by a) ligating the common carotid artery bilaterally, b) coagulating the right vertebral artery and c) exsanguinating the animal (removing 28-30 ml of blood). The induced ischaemia was studied by BP and PCO2 monitoring, CBF measurement, videomicroscopy of surface cerebral vessels, and finally macroscopic and microscopic examination of brain sections. In group C (8 animals)-moderate degree of CI-brain circulation improved in all animals after the application of the ECCC, installed at 135 min after the onset of CI. In 10 animals (group D) with severe and prolonged (225 min) CI, ECCC enhanced the brain circulation in eight animals to a variable degree.
- Brain 10/1967; 90(3):681-96. · 9.92 Impact Factor
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ABSTRACT: Antithrombin deficiencies may be the reason for seemingly unexplained thrombosis and graft failure. We treated seven patients who developed clotting difficulties as a result of antithrombin II and/or III deficiencies. In four, arterial thrombosis occurred after arterial reconstruction--three with occluded femoral grafts and one with runoff and digital vessel thrombosis that developed during profundoplasty. Two patients has spontaneous thrombosis of the arterial system of the vessels of the lower leg, and one developed ileofemoral phlebitis. Three patients had abnormally low levels of both antithrombin II and III, whereas two had low levels of antithrombin II only and two had low levels of antithrombin III. Of the four patients in whom this disorder occurred during vascular reconstruction, three experienced graft occlusion that resulted in below-knee amputation in two. There were no common predisposing factors. Antithrombin deficiency should be suspected when there is an unusual propensity to develop thrombus, when heparin cannot prolong coagulation time, and when measurements show reduced levels of antithrombin. Fresh frozen plasma should be given initially and long-term Coumadin therapy started. Early recognition and treatment is necessary to avoid limb loss or death.Surgery 07/1981; 89(6):735-42. · 3.37 Impact Factor
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ABSTRACT: Using the hydrogen clearance technique, local cerebral blood flow (LCBF) in 22 dogs was estimated at 6 parietal sites prior to and following 5 min of total global ischemia. Ischemia was immediately followed by an initial reactive hyperemia during which the electrocorticogram (ECoG) usually began to recover, and within the first 30 min, most of the LCBF's decreased to subnormal values. This onset of hypoperfusion was accompanied by a concomitant decrease in ECoG activity. Two animals that maintained normal local perfusion after the initial hyperemia recovered ECoG activity quickly. These results suggest that the subsequent poor reperfusion was caused by an increased microvascular resistance rather than by blood aggregates, increased blood viscosity, or a variety of other mechanism which have been proposed. Increased vascular tonus was, at least, partly responsible for the increased vascular resistance. This report supports the hypothesis that impaired reperfusion (which occurs some time after an initial hyperemia) may be responsible for ultimate neuronal death, rather than the period of global ischemic hypoxia per se.Stroke 11(5):534-41. · 6.16 Impact Factor