Carotid occlusion

In the emergency situation, we beheve this technique can be successfully employed in selected patients with symptomatic ischemia due to dissection or atherosclerotic disease despite being on maximal medical therapy. We have also seen patients with carotid occlusion and an isolated cerebral hemisphere (poor collateral flow) benefit from EC-IC bypass. Any potential benefit, however, must... 

Grubb Jr, RL, Derdeyn CP, Fritsch SM, Carpenter DA, Yundt KD, Videen TO, Spitznagel EL, Powers WJ. Importance of hemodynamic factors in the prognosis of symptomatic carotid occlusion. JAMA 1998 280 1055-1060. 

Carotid artery disease is one of the major causes of ischemic stroke. The predominant mechanisms by which it causes stroke are (a) arterial embolism from atherosclerotic plaques (b) hemodynamic changes, leading to watershed infarcts and (c) distal propagation of thrombus originating from acute carotid occlusion. ... 

Ohnishi (Sakamoto etal., 1991) has described an oligomeric derivative of prostaglandin Bi (PGB2) and ascorbic acid. In a rat bilateral carotid occlusion-reperfiision injury complicated by haemorrhagic hypotension, this compound reduced a-phenyl-r-butyl nitrone (PBN) spin-trapped radicals and thiobarbituric acid-reactive products (TBARs) (a measure of lipid peroxidation) in isolated... 

Idebenone, an inhibitor of lipid peroxidation, was shown to prolong survival time and delay the onset of ischaemic seizures in a bilateral carotid occlusion model in rats. It is marketed in Japan as a therapy to improve cerebral metabolism and performance after a stroke (Suno and Nagaoka, 1984). Cerebral protective effects after an ischaemic insult in dogs and rabbits have been seen with the hydroxyl radical scavenger, mannitol (Meyer et al., 1987). 

Cypros Pharm. Corp. describes the use of polyguanidino derivatives as presynaptic N- and P/Q-type calcium channel blockers for i.v. (or i.c.v.) administration (Marangos et al. (Cypros Pharmaceutical Corp.), W09836743). Compound 5 was administered to gerbils (7.5 mg/kg i.v.) prior to bilateral carotid occlusion. After 72 h the animals were sacrificed. Brains were perfusion-fixed and sections were stained to enable quantitative cell counts of live and dead neurons. The number of damaged neurons in the subiculum was 91.5 compared to 214 for a control treated with saline. It has been claimed that this compound can be used for the treatment of neuropathic pain and for the protection of neurons from excitatory damage under conditions of cerebral hypoxia. 

Thus, people who are prone to coronary ischemia or carotid occlusion may be at risk for heart attack or ischemic stroke when taking these COX-2 selective... 

Mofidi R, Crotty TB, McCarthy P Sheehan SJ, Mehigan D, Keaveny TV. Association between plaque instability, angiogenesis and symptomatic carotid occlusive disease. Br J Surg 2001 88 945-950. 

Due to the very low event rates in patients with asymptomatic lesions of moderate severity (<60% diameter stenosis), it is unknown whether currently available interventional techniques can improve long-term outcomes over those achievable with optimal medical management. Also unresolved are the indications for carotid stenting in asymptomatic individuals with contralateral carotid occlusion (53) and those undergoing major cardiac or vascular surgery (54). 

Soinne L, Helenius J, Saimanen E, Salonen O, Lindsberg PJ, Kaste M, Tatlisumak T (2003a) Brain diffusion changes in carotid occlusive disease treated with endarterectomy. Neurology 61 1061-1065... 

Markarian et al., 1996 SD rats MCAo and bilateral carotid occlusion 3 h, with reperfusion 32-33 and 36-37, for 1-4 h intra-and postischemia or delayed 15, 30, or 45 min after ischemia onset Infarct volume Reduced infarct volume (larger reductions with longer hypothermia), less effective when delayed 45 min... 

Kader et al., 1994 Wistar rats MCAo and bilateral carotid occlusion Permanent, lasting 0, 10, 20, or 60 min followed by death 33 and 36.5, intraischemia Nitrite levels, cGMP levels, NOS activity during ischemia Reduced nitrite and cGMP levels, reduced NOS activity... 

Bevilacqua et al. (1991) performed the same model in rabbit carotid arteries but compared the procedure in one artery before drug treatment with the contralateral artery after drug treatment. Heparin, the synthetic thrombin inhibitor FPRCH2C1, iloprost and t-PA inhibited carotid occlusion in this model but not aspirin. 

In two experimental models of ischaemia, it has been shown that HU-211 significantly increases cell survival. It was seen that after forebrain ischaemia produced by 20 min of carotid occlusion, the number of viable neurons in the hippocampal CA1 region of HU-211-treated rats was significantly higher than in controls. The same effect was seen in gerbils after 10 min of bilateral carotid occlusion on treatment with HU-211 [197, 198]. A related effect has been noted after rat optic nerve crush injury. Administration of HU-211 improved recovery of the nerve, with the visual evoked response amplitude increasing significantly [199],... 

Rothwell PM, Howard SC, Spence D (2003). Relationship between blood pressure and stroke risk in patients with symptomatic carotid occlusive disease. Stroke 34 2583-2590... 

Aaslid R, Lindegaard KF, Sorteberg W et al. (1989). Cerebral autoregulation dynamics in humans. Stroke 20 45-52 Adams HP Jr., Powers WJ, Grubb RL Jr., (2001). Preview of a new trial of extracranial-to-intracranial arterial anastomosis the carotid occlusion surgery study. Neurosurgery Clinics of America 12 613... 

The Carotid Occlusion Surgery Study. Neurosurgery Focus 14 e9... 

Fig. 9.4. Axial T2-weighted MRI scans (a-c) and a magnetic resonance angiogram (d) showing a right partia anterior circulation infarct secondary to right carotid occlusion.

Low flow may occur secondary to systemic hypotension, as during cardiac arrest. This results in bilateral infarcts, usually in the posterior boundary zones, and causes cortical blindness, visual disorientation and agnosia, and amnesia. Alternatively, a relatively small fall in systemic blood pressure in the presence of internal carotid occlusion or stenosis may cause unilateral boundary zone infarction, usually in the anterior and subcortical regions. This causes contralateral weakness of the leg more than the arm, with sparing of the face. 

Neurological examination is primarily to localize the brain lesion but there may also be clues as to the cause of the stroke a Horner s syndrome ipsilateral to a carotid distribution infarct suggests dissection of the internal carotid artery or sometimes acute atherothrom-botic carotid occlusion. Lower cranial nerve lesions ipsilateral to a hemispheric cerebral infarct can also occur in carotid dissection. 

Tenderness of the branches of the external carotid artery (occipital, facial, superficial temporal) points towards giant cell arteritis. Tenderness of the common carotid artery in the neck can occur in acute carotid occlusion but is more Ukely to be a sign of dissection, or arteritis. Absence of several neck and arm pulses in a young person occurs in Takayasu s arteritis (Ch. 6). Delayed or absent leg pulses suggest coarctation of the aorta or, much more commonly, peripheral vascular disease. Other causes of widespread disease of the aortic arch are atheroma, giant cell arteritis, syphihs, subintimal fibrosis, arterial dissection and trauma. 

Derdeyn CP, Grubb RL Jr., Powers WJ (2005). Indications for cerebral revascularization for patients with atherosclerotic carotid occlusion. Skull Base 15 7-14... 

Martin-Negrier ML, Belleannee G, Vital C et al. (1996) Primitive malignant fibrous histiocytoma of the neck with carotid occlusion and multiple cerebral ischemic lesions. Stroke 27 536-537... 

Powers WJ, Derdeyn CP, Fritsch SM et al. (2000). Benign prognosis of never-symptomatic carotid occlusion. Neurology 54 878-882... 

Experimental evidence indicates that COX modulates BBB permeability in neuroinflammatory conditions, ischemia, and hemorrhage. The COX inhibitor, KBT-3022, prevented brain edema induced by bilateral carotid occlusion and recirculation in gerbils (Yamamoto et al., 1996). In the collagenase model of intracerebral hemorrhage, the brain water content of rats treated with the COX-2 inhibitor, celecoxib, decreased both in lesioned and nonlesioned hemispheres in a dose-dependent manner, which was accompanied with reduced perihematomal cell death (Chu et al., 2004). Delayed damage to the BBB and vasogenic edema, which follow ischemic stroke, were significantly diminished by administration of... 

Dose = 2.5 mg kg i.v. No effect on carotid occlusion and noradrenaline pressor responses Inhibited CO and NA responses No effect on carotid occlusion but inhibited NA response p < 0.001 p < 0.05 p < 0.01 SE denotes the standard error HR denotes heart rate (bpm) f,decrease in heart beat rate, f increase in heart beat rate... 

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