Embolectomy for acute embolic occlusion of the internal carotid artery bifurcation

BACKGROUND: Acute occlusion of the distal intracranial segment of the internal carotid artery (ICA) causes sudden severe hemispheric ischemia. A low rate of recanalization and a high mortality rate for this condition have been noted, even with endovascular treatment. METHODS: We report the results of emergency embolectomy in six patients with acute embolic occlusion of the internal carotid artery (ICA) bifurcation. All six patients were admitted to our institute within 2 h of the onset of symptoms. Computed tomography (CT) scans on admission revealed no low-density or high-density regions in any patients. The time between onset of symptoms and completion of angiography ranged from 2 to 4 h (2.8 +/- 0.7 h). RESULTS: Emergency embolectomy was performed for each patient. Recanalization was confirmed angiographically in four of the patients. In the remaining two patients, massive infarction in the territory of the ICA was detected on the CT scans obtained the day of the operation, and postoperative angiography was not performed in these two cases. These two patients died of uncal herniation 6 days after onset. Two of the six patients were able to walk with a cane 2 months after surgery. The remaining two patients were unable to walk or attend to their own bodily needs without assistance. The time elapsed between onset of symptoms to reopening of the occluded vessel was within 6 h in the four surviving patients. The recanalization rate was 66.7% (4/6) for the embolectomy procedure, significantly higher than that (12.5%) of the thrombolytic therapy reported in a previous study. CONCLUSIONS: In summary, open embolectomy can be performed when the time after onset of symptoms is less than 6 h.     

Outcome analysis of carotid artery occlusion

The outcome of carotid artery occlusion was studied through the retrospective identification of 115 affected patients. The majority were white (77%) males (61%) with multiple atherogenic risk factors and suffering ipsilateral stroke (57%). Those patients presenting with stroke were not distinguished by demographic features, risk factors, lipid profile, medical regimen, or subsequent mortality when compared with those without. Overall, 36 patients (31%) required contralateral carotid endarterectomy (CEA), with one (2.8%) perioperative stroke, whereas 4 (3%) underwent ipsilateral external CEA without incident. With 81% follow-up (mean 3.9 years), the overall mortality of the group was 46%; the annualized risk of ipsilateral stroke was 1.6%. This study documents a significant risk of stroke and contralateral occlusive disease with ipsilateral carotid artery occlusion, which cannot be reliably predicted by clinical criteria. Duplex surveillance is valuable, but flow velocity measurements alone may be misleading. Surgical endarterectomy can be performed with an acceptable rate of perioperative stroke.     

Cerebral hemodynamics in patients with carotid artery occlusion and contralateral moderate or severe internal carotid artery stenosis

OBJECT: The purpose of this study was to evaluate cerebral hemodynamics in patients suffering from occlusion of the carotid artery (CA) and contralateral CA stenosis. METHODS: Using transcranial Doppler ultrasonography, the cerebrovascular reactivity to hypercapnia in the middle cerebral arteries was evaluated by calculating the breath-holding index (BHI) of 69 symptomatic patients suffering from internal CA (ICA) occlusion and moderate or severe contralateral ICA stenosis. To evaluate which variables influenced BHIs ipsilateral to the site of ICA occlusion, a multiple stepwise linear regression analysis was performed that included the following factors: patient age, percentage of contralateral ICA stenosis, contralateral BHI, number of collateral pathways, and presence of hypertension, diabetes, smoking, and hyperlipidemia. An analysis of variance was conducted to evaluate the impact of the type of collateral vessels on the BHI. A regression analysis showed that the BHI ipsilateral to the site of ICA occlusion could be accounted for by the contralateral BHI (which was entered at the first step of the analysis, p < 0.001) and by the number of collateral pathways (which was entered at the second step, p = 0.033). Neither the degree of contralateral ICA stenosis nor the other variables could be added to improve the model. The analysis demonstrated that the absence of collateral pathways and the presence of the anterior communicating artery (ACoA) alone were associated with lower BHI values than those found in the presence of two or three collateral vessels, regardless of the presence of an anterior collateral pathway. CONCLUSIONS: On the basis of these data one can infer that the cerebral hemodynamic status of patients with occlusive disease of the CA is influenced by individual anatomical and functional characteristics. Because improvement in contralateral hemodynamics after surgical correction of an ICA stenosis can only be expected in the presence of an ACoA, the planning of strategies for influencing cerebral blood flow distal to an ICA occlusion and, in particular, the consideration of a contralateral carotid endarterectomy, should be preceded by a careful evaluation of the intracranial hemodynamic adaptive status of the patient. Particular attention should be paid to cerebrovascular reactivity and the number and type of collateral vessels that are present.     

Experiments on carotid artery flow increase as a result of contralateral carotid occlusion

Summary No infallible preoperative method exists to predict accurately a patient's tolerance to unilateral carotid artery ligation. It has recently been hypothesized that the magnitude of increase in contralateral carotid artery flow resulting from trial compression of the ipsilateral common carotid artery might be of value in determining the result of permanent ligation. The purpose of this study is to evaluate three factors which might influence the contralateral flow increase: the carotid sinus reflex, the vertebro-basilar artery circulation, and the degree of anastomotic crossover in the anterior part of the circle of Willis.The effects of these three factors were studied in the following situations: (1) Before and after ablation of the ipsilateral carotid sinus in eight dogs (by cutting the ninth and tenth cranial nerves); (2) Before and after ligation of both vertebral arteries in three dogs: (3) Before and after separation of the anterior circle of Willis by clipping an anterior cerebral artery in two monkeys.Results: (1) Carotid sinus denervation had no effect in three dogs, diminished the increase by an average of 25% in three dogs, and enhanced the increase by an average of 50% in two dogs: (2) Bilateral vertebral artery ligation enhanced the increase in all three dogs by an average of 66%; (3) Separation of the anterior circle of Willis caused a diminution of the increase in both monkeys by an average of 66%; (4) There was no relationship between the degree of contralateral flow increase and 1. systemic blood pressure, 2. contralateral flow prior to occlusion, or 3. ipsilateral flow prior to occlusion.Conclusions: (1) In the experimental situation, the carotid sinus reflex is not consistently responsible for the contralateral carotid flow increase; (2) The observations on the vertebral artery occlusion and monkey studies lend support to the concept that if a contiguous vascular bed is removed from access to carotid blood, the flow through the system will decrease, and vice versa. The data are placed into clinical perspective.This work was supported in part by a grant from the U.S. Public Health Service (2 T01 NB 5465).     

Congenital absence of the external carotid artery: atherosclerosis without a bifurcation

We report the case of a patient with congenital absence of the external carotid artery in whom we performed a carotid endarterectomy. The radiographic features and operative findings are presented. Four similar cases previously reported in the literature are reviewed. A comment on the pathophysiology of atherosclerosis at the carotid bulb in the absence of a bifurcation and a brief discussion on the possible embryologic explanation of this anomaly are discussed.     

Internal carotid artery stenosis and external carotid artery occlusion with unusual extracranial collateral pathway: case report

A patient with stenosis of the internal carotid artery and occlusion of the external carotid artery associated with an unusual extracranial collateral pathway is presented. A 63-year-old man was hospitalized for sudden onset of black-out after urination. He was alert, and no neurological deficit was found. MRI showed multiple lacunae in the bilateral putamens. Cerebral angiogram demonstrated severe stenosis of the left internal carotid artery at its cervical segment and complete occlusion of the left external carotid artery at its origin. The ascending pharyngeal artery originated from the left internal carotid artery above its stenotic lesion and the superior thyroid artery originated from the left common carotid artery. The sternocleidomastoid branch from the left superior thyroid artery and the muscular branch from the left vertebral artery anastomosed with the muscular branch of the ascending pharyngeal artery. The ascending pharyngeal artery maintained patency of the internal carotid artery. It is important to perform vertebral angiography when there is proximal occlusion and severe stenosis of the internal carotid artery, and when the ascending pharyngeal artery has not been clearly identified as a branch from the ipsilateral external carotid artery on the common carotid angiogram.     

颈内动脉完全闭塞的手术治疗

目的 探讨颈动脉血运重建治疗完全性颈内动脉闭塞的临床疗效.方法 2001年6月～2010年4月,收治颈动脉狭窄患者397例,术前行磁共振血管造影(MRA)检查,确诊并行颈动脉内膜切除术(CEA)治疗颈内动脉闭塞患者28例,术中切除标本送病理检查,术后复查颈部MRA,并对术后情况进行随访.结果 术后即时通畅率为92.8％,术后平均随访时间10个月,22例颈内动脉通畅,通畅率为78.5％,无脑缺血事件发生;6例颈内动脉闭塞患者中,2例在术后4个月发生短暂性脑缺血及腔隙性梗死;3例术后仍偶有头晕,其中2例单侧肢体麻木;1例记忆力减退.结论 对于有症状的颈内动脉闭塞患者,CEA加取栓术是安全有效的方法.     

A case of a basilar bifurcation aneurysm associated with common carotid artery occlusion

A case of a basilar bifurcation aneurysm associated with common carotid artery occlusion is reported. A 40-year-old woman was admitted to our hospital with severe headache and nausea. On admission, no neurological abnormality was observed. CT scan showed thin subarachnoid hemorrhage in the basal cistern. Left vertebral angiograms revealed a basilar bifurcation aneurysm located in the high position. Also, the left internal and external carotid arteries were supplied through the anastomotic muscle branches of the left occipital and vertebral artery. The trunk of the left common carotid artery was not visualised from its origin on the aortogram. CT scan at the level of C6 showed thinning of the left common carotid artery and contrast enhancement study indicated occlusion. Neck clipping of the aneurysm was successfully performed by right trans-sylvian approach. Right zygomatic arch was removed to obtain a wider operative field for avoiding further retraction of the brain tissue. The postoperative course was uneventful except transient disorientation for two weeks. It has been well known that internal carotid artery occlusion may be associated with cerebral aneurysm in some cases. However, it seemed to be a rather rare case that the common carotid artery occlusion due to arteriosclerosis was associated with cerebral aneurysm. Hemodynamic factor was positively suggested for aneurysmal formation in this case.     

Restoration of blood flow in the external carotid artery

The external carotid artery revascularization procedures were performed in 19 cases. Fourteen patients had ischemic stroke history. Ten patients had occluded the ipsilateral internal carotid artery to the stenosed external carotid artery. Six patients had occluded the common as well as internal carotid artery on the same side. Positive neurologic changes were obtained in 73.7% of the operated patients. The external carotid artery revascularization procedures are recommended in cases when the ipsilateral internal carotid artery is occluded.     

Effect of carotid artery stenting on the external carotid artery

OBJECTIVE: We studied the fate of the ipsilateral external carotid artery (ECA) after stenting of the internal carotid artery (ICA) compared with the contralateral ECA. SUBJECTS AND METHODS: One hundred twenty-one ipsilateral ECAs in 112 consecutive patients who underwent carotid artery Wallstent placement were prospectively studied with color-coded duplex sonographic scanning (CCDS) and compared with 83 contralateral ECAs over 2 years. CCDS was scheduled for the day before (day 0), the day after (day 1) and 3, 6, 12, and 24 months after stenting. Development of ECA occlusive disease was evaluated with ECA-common carotid artery flow ratio (peak systolic velocity). For estimation of ECA stenosis 70% or greater, flow ratio 4.1 was used as the cutoff point. RESULTS: Before and after stenting, two and three (one additional) ECA occlusions were seen. Median grade of ECA stenosis on day 1 did not significantly change at angiography (P = 1.0; tendency of increase) or CCDS (P =.27; tendency of decrease).At follow-up (day 1-24 months, CCDS only), frequency of stenosis 70% or greater in the ipsilateral ECA was 21 of 120 (17.5%) on day 1 and 41 of 107 (38.32%) at 24 months, and 3 of 107 (2.5%) and 5 of 107 (4.67%) ECA occlusions were registered at the two time points. Progression of disease, as demonstrated by increase in flow ratio over time, was much more pronounced in the ipsilateral ECAs compared with the contralateral ECAs (P =.0002).In stented ICA, 2 (1.85%) asymptomatic recurrent stenoses 70% or greater were found at CCDS.One of three patients with new ECA occlusions reported jaw claudication for 10 days. Perioperative stroke (one major, four minor) occurred in 5 of 121 patients (4.46%). Two minor strokes caused by embolization occurred during the first year. CONCLUSION: The more pronounced progression of arteriosclerotic disease at the orifice of the ipsilateral ECAs during the first year after carotid stenting might be due to local factors of the ICA stent. Its clinical significance in respect to the effect of the ECA as collateral supply to the brain might depend on the incidence of carotid stent rerecurrent stenosis, which was low in the present study.     

The hemodynamic effects of internal carotid artery stenosis and occlusion

The purpose of this study was to determine in subhuman primates whether hemodynamic mechanisms (as compared with embolic mechanisms) contribute to cerebral ischemia following carotid artery occlusion or stenosis. Following carotid artery occlusion there was loss of cerebral autoregulation: cerebral blood flow (CBF) measured with the xenon-133 technique became passively dependent upon the mean arterial blood pressure (MABP) over an MABP range of 30 to 110 mm Hg. By contrast, autoregulation was preserved in normal animals and in animals with a 90% carotid artery stenosis. Regional CBF was measured with carbon-14-labeled iodoantipyrine autoradiography in normotensive baboons, in hypotensive animals, and in hypotensive animals with carotid artery occlusion or stenosis. With carotid artery occlusion and hypotension, reduced levels of local CBF were seen ipsilaterally in the boundary zones between the anterior and middle cerebral arteries with 35% of the area of an anterior section through the hemisphere displaying a CBF value of less than 20 ml/100 gm/min. Comparable values with hypotension were 21% with carotid artery stenosis, 20% with no proximal vascular lesion, and 1% in normotensive animals. These areas of reduced CBF corresponded with areas of boundary-zone ischemia seen with light microscopy. The study suggests that while hemodynamic ischemia develops with carotid artery occlusion, it does not occur with even a 90% carotid artery stenosis or in normal animals.     

Basilar bifurcation aneurysm associated with internal carotid artery occlusion. Report of two cases

Two cases of subarachnoid hemorrhage caused by rupture of a basilar bifurcation aneurysm associated with occlusion of the internal carotid artery (ICA) at the neck are presented. Case 1, a 71-year-old female, was hospitalized in a coma. Angiography demonstrated occlusion of the bilateral ICA, collateral blood supply through the branches of the foramen rotundum or vidian artery from the maxillary arteries and right posterior communicating artery, and a saccular aneurysm at the basilar bifurcation. The patient died 1 month later following rerupture of the aneurysm. Case 2, a 64-year-old male, was hospitalized for drowsiness. Angiography showed occlusion of the right ICA, collateral blood supply through a tortuous artery (a vidian artery), and a large aneurysm at the basilar bifurcation. Posterior circulation supplied anteriorly through the right posterior communicating artery. The patient died 1 month later because of rerupture of the aneurysm. Laminar thrombosis of the right ICA and an anastomotic vessel, seemingly a branch of the foramen rotundum or a vidian artery, were demonstrated by autopsy. The combination of cerebral aneurysm and collateral circulation is extremely rare in cases of occlusion of the ICA. The two cases described here suggest that hemodynamic stress is an important factor in the formation of cerebral aneurysms.     

Impact of external carotid artery occlusion at declamping of the external and common carotid arteries during carotid endarterectomy on development of new postoperative ischemic cerebral lesions

Objective

The external carotid artery (ECA) is inadvertently occluded during carotid endarterectomy (CEA). The importance of ECA occlusion has been emphasized as a loss of extracranial to intracranial collaterals, a source of chronic embolization, or a site for extended thrombosis during wound closure. This study aimed to determine whether ECA occlusion that inadvertently developed during endarterectomy and that was eventually detected using blood flow measurement of the ECA after declamping of all carotid arteries is a risk factor for development of new postoperative ischemic lesions at declamping of the ECA and common carotid artery (CCA) while clamping the internal carotid artery (ICA). This study also aimed to determine whether intraoperative transcranial Doppler (TCD) monitoring predicts the risk for development of such lesions.

硝苯地平对大鼠颈总动脉端端吻合术后血流速度的影响

目的 研究硝苯地平（ｎｅｆｅｄｉｐｉｎｅ））对小动脉端端吻合后血流速度的影响。为血管吻合后临床应用硝苯地平的时间提供依据。方法 取ＳＤ大鼠４８只,切断左侧颈总动脉后作端端吻合。按术后所给药物的不同随机分成两组。实验组：术后用硝苯地平灌胃（１．０ｍｇ／ｋｇ）;对照组用同等体积生理盐水灌胃。按给药时间又分成术后２４、４８和７２ｈ３个给药时间组。每组均在给药后１、３、５和７ｈ,用彩色多普勒超声仪检测左侧     

Esmolol decreases the adverse effects of acute coronary artery occlusion on myocardial metabolism and regional myocardial blood flow in dogs

This study was designed to test the hypothesis that beta-adrenergic receptor blockade with esmolol would decrease the hemodynamic and myocardial metabolic impairment produced by left anterior descending coronary artery (LADa) occlusion. Twenty-three anesthetized open-chest dogs underwent direct cannulation of the LADa, its companion vein (LADv), and a distal circumflex vein (CFXv) for blood sampling. All dogs were subjected to two consecutive 15-minute periods of total LADa occlusion; group 1 (n = 11) received an infusion of esmolol (150 micrograms.kg-1.min-1) during either occlusion period (randomly assigned) and group 2 (n = 12) received no intervention during either occlusion period. One hour of reperfusion was interposed between the two periods of LADa occlusion. Hemodynamic measurements were made and blood was sampled from the aorta, CFXv, LADa, and LADv before and during both periods of LADa occlusion. Without esmolol infusion, LADa occlusion was associated with decreases in stroke index, coronary perfusion pressure, and left ventricular stroke work index; with esmolol infusion these hemodynamic decrements did not occur. During both LADa occlusion periods in both groups, lactate extraction became negative, i.e., there was net lactate production. Despite this, the magnitude of lactate production was less with esmolol than without it. Finally, average endocardial-to-epicardial blood flow ratio in the LAD perfusion area was decreased during each LAD occlusion period except when esmolol was infused, during which the baseline value was maintained. Thus, infusion of esmolol during temporary LADa occlusion preserved certain hemodynamic variables, preserved the ratio of endocardial-to-epicardial blood flow, and decreased the apparent magnitude of lactate production.     

Cyanoacrylate occlusion of carotid-cavernous fistula with preservation of carotid artery flow.

We report a new treatment for carotid-cavernous fistula. Using a flow-guided, balloon-tipped microcatheter, we catheterize the fistula itself, verify balloon entry into the fistula with fluoroscopy and x-ray films, and then infuse the tissue adhesive isobutyl-2-cyanoacrylate with careful fluoroscopic control. Three patients have had their fistulas occluded, with preservation of flow through the internal carotid artery. This balloon microcatheter allows the radiologist to perform a reversible test occlusion. All three patients had neurological changes during or after the procedure, and in one we inadvertently occluded several distal middle cerebral artery branches without permanent neurological deficit. No patient became blind or developed 3rd, 4th, or 6th nerve palsy from the treatment. This technique seems to have promise as another method for the obliteration of carotid-cavernous fistula.