Changes in intracranial stenotic lesions after extracranial-intracranial bypass surgery

The natural history of intracranial arterial stenosis is not well understood. The lesions are pathologically quite diverse, and are subject to resolution, progression, or occlusion. The authors undertook an investigation to examine what effects, if any, extracranial-intracranial (EC-IC) bypass surgery had on the evolution of intracranial arterial stenosis in 18 patients undergoing EC-IC bypass procedures for ipsilateral hemispheric ischemia. There was inaccessible internal carotid artery stenosis in 14 patients, and middle cerebral artery stenosis in four patients. Early (within 2 weeks) and late (at 6 months) postoperative angiography was performed in all patients. During the period of the study, there was a significant change in the arterial stenosis in 50% of the patients (nine of 18). The stenotic artery became occluded in four patients while the grafts were widely patent. The occlusion occurred within a few days after the operation in three of the four cases, and was accompanied by an ischemic stroke in these patients. There was improvement or resolution of the stenotic lesion in five patients; the graft became occluded in two of these cases and was patent but showed poor cortical artery filling in the other three. All these patients remained asymptomatic and the change was detected on routine late postoperative angiograms. It is concluded that arterial stenoses should not be viewed as static or inflexible lesions, and that EC-IC bypass procedures can modify the hemodynamic parameters across stenotic lesions, predisposing them to improvement or worsening. This, in turn, may affect bypass patency. Such hemodynamic interactions are accompanied by ischemic symptoms in some patients, and contribute to the relatively higher morbidity associated with EC-IC bypass surgery in the setting of arterial stenosis.     

Emergency EC-IC bypass for symptomatic atherosclerotic ischemic stroke

Previous studies have shown that extracranial–intracranial (EC-IC) bypass surgery has no preventive effect on subsequent ipsilateral ischemic stroke in patients with symptomatic atherosclerotic internal carotid occlusion and hemodynamic cerebral ischemia. A few studies have assessed whether an urgent EC-IC bypass surgery is an effective treatment for main trunk stenosis or occlusion in acute stage. The authors retrospectively reviewed 58 consecutive patients who underwent urgent EC-IC bypass for symptomatic internal carotid artery or the middle cerebral artery stenosis or occlusion between January 2003 and December 2011. Clinical characteristics and neuroimagings were evaluated and analyzed. Based on preoperative angiogram, responsible lesions were the internal carotid artery in 19 (32.8 %) patients and the middle cerebral artery in 39 (67.2 %). No hemorrhagic complication occurred. Sixty-nine percent of patients showed improvement of neurological function after surgery, and 74.1 % of patients had favorable outcome. Unfavorable outcome was associated with insufficient collateral flow and new infarction after bypass surgery.     

Cerebral revascularization for ischemic disease in the 21st century

Shortly after the first extracranial to intracranial (EC-IC) carotid artery bypass was performed by Yasargil in 1967 for internal carotid artery occlusion, cerebral revascularization became widely accepted in the neurosurgical field, and the procedures became increasingly used as practitioners began to master the technical aspects of the surgery. The procedures were performed for intracranial arterial stenosis and occlusion and used as an adjunct in the treatment of large aneurysms and skull base tumors. The results of the EC-IC bypass group trial in 1985 were surprising to many and sobering to all; EC-IC bypass for stenosis or occlusion of the high internal carotid artery or middle cerebral artery did not decrease the risk of subsequent stroke compared with medical management. Rather, the incidence of stroke increased, and the events were noted to occur sooner than with medical therapy alone. Despite the known limitations of this landmark study, the number of EC-IC bypass procedures fell precipitously over the ensuing decades. Despite this significant setback, cerebral revascularization is not obsolete. This article revisits the sequence of events leading to the rise of revascularization surgery and recaps the impact of the EC-IC bypass trial. The limitations of the trial are discussed, as are current studies evaluating the efficacy of cerebrovascular bypass procedures for symptomatic carotid occlusive disease. The authors review the accepted indications for bypass surgery in the early 21st century.     

Hemodynamic compensation via an excimer laser-assisted, high-flow bypass before and after therapeutic occlusion of the internal carotid artery

OBJECTIVE: High-flow, extracranial-intracranial (EC-IC) bypass operations are performed to prevent strokes among patients with giant aneurysms who cannot tolerate internal carotid artery (ICA) occlusion. However, the volume flow through the bypass, compared with preoperative ICA flow, has not been evaluated for any type of bypass. We describe a prospective case study that tested the ability of the high-flow EC-IC bypass to replace the volume flow of the ipsilateral ICA after deliberate ICA occlusion. METHODS: Seven consecutive patients with giant aneurysms of the ICA who experienced test occlusion failure underwent nonocclusive, excimer laser-assisted, EC-IC bypass surgery before permanent ICA occlusion. Volume flow values in the ICAs, the basilar artery, the EC-IC bypass, and the middle cerebral arteries were measured with magnetic resonance angiography. RESULTS: No significant changes in volume flow to the ipsilateral and contralateral hemispheres were observed after bypass surgery and therapeutic ICA occlusion. Before bypass surgery, the volume flow through the ipsilateral ICA was 243 +/- 74 ml/min, that through the contralateral ICA was 264 +/- 32 ml/min, and that through the basilar artery was 141 +/- 43 ml/min. After bypass surgery and therapeutic occlusion of the ipsilateral ICA, the volume flow through the bypass was 199 +/- 72 ml/min, that through the contralateral ICA was 303 +/- 82 ml/min, and that through the basilar artery was 153 +/- 72 ml/min. No significant preoperative versus postoperative changes in middle cerebral artery flow were observed on either side. CONCLUSION: The flow through the high-flow EC-IC bypass was able to replace the volume flow of the ipsilateral ICA after deliberate ICA occlusion for the treatment of giant aneurysms.     

Clinical results of extracranial-intracranial bypass surgery in patients with hemodynamic cerebrovascular disease

The importance of hemodynamic factors in the pathogenesis and treatment of cerebrovascular disease remains uncertain. The extracranial-intracranial (EC-IC) bypass trial has been criticized for failing to identify and separately analyze those patients with chronic reduction in regional cerebral perfusion pressure (rCPP) who might be most likely to benefit from surgery. Positron emission tomography (PET) measurements of regional cerebral blood flow (rCBF) and blood volume (rCBV) were performed on 29 patients with symptomatic occlusion or intracranial stenosis of the carotid arterial system prior to undergoing EC-IC bypass surgery. Twenty-four patients had evidence of reduced rCPP (increased rCBV/rCBF ratio) distal to the arterial lesion. Of 21 patients who survived surgery without stroke, three suffered ipsilateral ischemic strokes during the 1st postoperative year. A nonrandomized control group of 23 nonsurgical patients' with similar clinical, arteriographic, and PET characteristics experienced no ipsilateral ischemic strokes during the 1st year following PET. Based on these results in 44 patients, the probability that successful surgery reduces the occurrence of ipsilateral ischemic stroke 1 year later was calculated. This probability ranged from 0.045 for a 50% reduction to 0.168 for a 10% reduction. Thus, there was little evidence to suggest that measurements of cerebral hemodynamics can identify a group of patients who would benefit from EC-IC bypass surgery.     

Improvement of ischemic symptoms and cerebral blood flow after percutaneous transluminal angioplasty for renovascular hypertension. Report of a case with multiple cerebrovascular occlusive disease]

A 53-year-old male complained of frequent left motor-sensory transient ischemic attack for 4 months. On admission, he demonstrated mild right hemiparesis, dysarthria, and right hemisensory disturbance of all modalities. Cerebral angiography demonstrated complete occlusion of the left internal carotid artery just above the origin of the ophthalmic artery and a stenotic lesion at the horizontal segment of the right middle cerebral artery. Renal angiography showed severe stenosis of the right renal artery. Systolic blood pressure was over 200 mmHg and marked circadian variation of blood pressure was noted. Serum renin was 4.0 ng/ml/hr. Four months after superficial temporal artery-middle cerebral artery anastomosis, left carotid angiography showed good patency of the bypass and the ischemic symptoms completely disappeared. Single photon emission computed tomography (SPECT) showed increased cerebral blood flow (CBF), especially in the left hemisphere after surgery. Six months after the bypass surgery, he complained of mild right hemiparesis again. Shortly after percutaneous transluminal angioplasty (PTA) for renal arterial stenosis, his hemiparesis was improved and the systolic blood pressure stabilized to 150-170 mmHg. SPECT showed the CBF had also recovered in both hemispheres. The improvement in ischemic symptoms and increased CBF after PTA were probably related to stabilization of the systemic blood pressure or inhibition of serum renin-angiotensin.     

Basilar artery occlusion after STA-SCA anastomosis; case report

A case of basilar artery occlusion after STA-SCA bypass surgery is reported. The patient was a 56 year old male and presented a TIA of vertigo and speech disturbance. The preoperative angiogram revealed severe stenosis of the basilar artery in its midportion between the bifurcation of AICA and that of SCA. After surgery, the patient's clinical course was uneventful, but the angiogram showed that the previous stenotic segment of the basilar artery had been occluded and the distal portion of the basilar artery and its branches were perfused through the widely-patent STA-SCA bypass. About 6 months after the operation, the patient developed a pontine infarction in the right paramedian region, which was confirmed on MRI. The angiogram revealed that the occlusion of the basilar artery extended further proximally to a point just distal to the bifurcation of AICA. So it was suspected that the perforating branches of the basilar artery to the pons were occluded with the extension of the thrombosis of the basilar artery. The hemodynamic changes associated with the EC-IC bypass was thought to be responsible for the occlusion of the previous stenotic lesion.     

Complete arterial coronary revascularisation using radial artery conduit for double thoracic artery inlet flow: arterial sling operation.

BACKGROUND: Coronary artery bypass graft surgery with arterial revascularisation of all diseased coronary vessels is considered highly efficient because arterial grafts have an excellent long-term patency compared with venous grafts. However, problems to reach the infero-lateral wall with the in situ internal thoracic arteries usually require alternative techniques. We present the first results of a new surgical principle using a free radial artery segment to complete the arterial coronary revascularisation and concomitantly connect the internal thoracic arteries. METHODS: In patients referred for coronary bypass surgery and three-vessel disease an end-to-end anastomosis of the right internal thoracic artery and the radial artery segment preceded cardiopulmonary bypass, during which side-to-side anastomoses of the radial artery segment were used to revascularise stenotic branches of the right coronary and circumflex arteries. The left internal thoracic artery was used for revascularisation of stenotic branches of the left anterior descending artery, and finally an end-to-side anastomosis of the radial artery segment to the left internal thoracic artery was performed. Coronary artery blood flow was measured in 41 patients with Doppler flow probe. RESULTS: One hundred and ninety-two coronary anastomoses (an average of 4.2 per patient) were performed in 46 patients. We measured a mean total blood flow in the arterial sling graft of 104ml/min (range 35-221ml/min), compared with 69 and 68ml/min of the single inlet right and left internal thoracic arteries, respectively (P<0.01). Flow capacities of 104 and 120ml/min of the right and left internal thoracic arteries were measured during clamp of both the aorta and the contralateral internal thoracic artery. The mean crossclamp duration was 77min (range 51-113min). Postoperative angiography demonstrated patent graft anastomoses to all coronary arteries. There were no perioperative deaths or myocardial infarctions. One patient had a minor postoperative stroke. DISCUSSION: Complete arterial revascularisation can be achieved by the arterial sling operation with an acceptable crossclamp time and a high early rate of graft patency. The double arterial inlet provides a 50% higher blood flow to the beating heart and two-fold increase in the flow reserve compared with a single inlet. Although further research including long-term follow-up of this new principle is required, the present findings seem promising and suggest that the arterial sling operation has a potential role for complete arterial coronary revascularisation.     

Impact of immediate cerebral angiography for in-hospital cerebral thromboembolism after cardiovascular surgery

OBJECTIVES: Postoperative stroke remains a serious problem in cardiovascular surgery. We studied the role of cerebral angiography in postcardiotomy stroke. METHODS: We retrospectively analyzed 5 in-hospital patients with stroke due to cerebral thromboembolism after cardiovascular surgery. RESULTS: The incidence of in-hospital cerebral thromboembolism was 0.5%, involving 5 patients among 913 adults undergoing cardiovascular operations. In-hospital cerebral thromboembolism occurred 3 to 9 days (average: 7 +/- 2 days) after surgery. Causes of cerebral thromboembolism were chronic atrial fibrillation in 1, transient atrial fibrillation in 2, artificial valve in 1, and intracranial arterial stenosis in 1. Immediate cerebral angiography, after exclusion of intracranial hemorrhage and complete cerebral infarction by computed tomography, revealed cerebral embolism in 3 and cerebral thrombosis in 2 with occlusion or stenosis of intracranial arteries. Local intraarterial administration of a thrombolytic agent was done in the 3 patients with cerebral embolism and occluded arteries were recanalized. Fibrinolysis was not done in 2 because of recanalized arteries or sufficient peripheral blood supply through collateral feeders. No patients exhibited rebleeding into the pericardial space or wound bleeding. All patients survived with moderate or full functional recovery. CONCLUSION: Immediate cerebral angiography with/without local thrombolysis may improve functional outcome and survival in patients with postcardiotomy cerebral thromboembolism.     

Risk of intraoperative ischemia due to temporary vessel occlusion during standard extracranial-intracranial arterial bypass surgery

OBJECT: Standard extracranial-intracranial (EC-IC) arterial bypass surgery represents a well-recognized procedure in which the aim is to augment distal cerebral circulation. The creation of the bypass requires temporary occlusion of the recipient vessel. Thus, there exists controversy about the risk of standard EC-IC arterial bypass surgery causing ischemic complications due to temporary vessel occlusion. In this prospective study, the incidence of intraoperative ischemia was investigated in symptomatic patients with steno-occlusive cerebrovascular disease and existing hemodynamic insufficiency. METHODS: Twenty consecutive patients (14 women and 6 men; mean age 46 +/- 11 years) suffering from recurrent transient ischemic attacks due to occlusive cerebrovascular disease and proven hemodynamic compromise in functional blood flow studies were enrolled in this study. The underlying pathological condition was internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion in 6 cases and ICA or MCA stenosis in 3 cases, whereas 11 patients presented with moyamoya syndrome or moyamoya disease. The surgical procedure consisted of the establishment of a standard superficial temporal artery (STA)-MCA bypass, and was performed while a strict intraoperative management protocol was applied. Patients underwent clinical examination and magnetic resonance (MR) imaging within 48 hours before and after surgery. RESULTS: The incidence of reversible clinical signs of ischemia was 2 (10%) of 20 patients. Postoperative MR imaging revealed signs of diffusion disturbances in 2 (10%) of 20 cases. The observed diffusion-weighted imaging changes, however, were situated within the dependent vascular territory at risk for ischemia in 1 patient only. No permanent neurological deficit occurred. The temporary vessel occlusion time ranged between 25 and 42 minutes (mean 33 +/- 7 minutes). All means are expressed +/- the standard deviation. CONCLUSIONS: Temporary vessel occlusion during standard STA-MCA arterial bypass surgery carries a low risk of intraoperative ischemia when a strict perioperative management protocol is applied.     

Identification of the optimal cortical target point for extracranial-intracranial bypass surgery in patients with hemodynamic cerebrovascular insufficiency

OBJECT: The objective of this report is to describe a new approach to identify the optimal cortical target point for extracranial-intracranial (EC-IC) bypass surgery, to reliably find suitable recipient vessels for the anastomosis. METHODS: Thirty consecutive patients (17 men and 13 women; mean age 54.6 +/- 11.79 years [+/- standard deviation]) with hemodynamic cerebrovascular insufficiency due to stenoocclusive arterial disease underwent EC-IC bypass surgery. The end of the Sylvian fissure was identified preoperatively using a specially designed template and external landmarks. At surgery, a 3-cm trephination was made, centered over the target point as determined by the template. The number, diameter, and length of the exposed cortical arteries were assessed using photographs and indocyanine green (ICG) angiograms. RESULTS: At least 1 recipient artery appropriate for anastomosis (>or= 1 mm) was found in every craniectomy. The mean number of suitable recipient arteries per craniotomy was 2.09 +/- 0.87, the mean diameter was 1.28 +/- 0.24 mm, and the mean length 10.83 +/- 4.87 mm. Bypass patency was confirmed by intraoperative ICG angiography, postoperative computed tomography angiography, and digital subtraction angiography, and reached 100%. CONCLUSIONS: Performing a 3-cm craniectomy over the described target point, reliably allows access to suitable recipient arteries for EC-IC bypass surgery.     

Construction of a new posterior communicating artery in a patient with poor posterior fossa circulation: technical case report

OBJECTIVE AND IMPORTANCE: The carotid and the vertebrobasilar circulation were connected, effectively creating a new posterior communicating artery (PComA). The excimer laser-assisted nonocclusive anastomosis technique is a new anastomosis technique whereby formerly untreatable patients may be treated with an intracranial artery-to-intracranial artery bypass procedure. This report is the first one in which an angiographically proved patent internal carotid artery-posterior cerebral artery segment P1 bypass is presented. CLINICAL PRESENTATION: Our patient presented with repeated episodes of vertebrobasilar ischemia because of vertebral artery occlusion and stenosis. INTERVENTION: An internal carotid artery-posterior cerebral artery segment P1 bypass procedure was performed. Because the patient experienced transient ischemia in the left cerebral hemisphere at the end of postoperative angiography procedure, no radiological intervention was performed, and the patient refused to undergo a new radiological intervention at a later stage. TECHNIQUES: Both anastomoses were made using the excimer laser-assisted nonocclusive anastomosis technique. CONCLUSION: Intraoperative flowmetry was performed using an ultrasound flowmeter, which disclosed blood flow of 35 ml/min through the bypass. We hope that this new PComA suffices to protect the patient from infarction in the territory of the vertebrobasilar circulation.     

Hemodynamic study of internal carotid artery stenosis and occlusion: value of combined isotopic measurements of regional cerebral blood flow and blood volume

The assessment of the intracranial hemodynamic consequences of obstructive lesions of the carotid artery by measuring resting rCBF is inadequate because cerebral blood flow may remain constant in spite of significant drops in the intraluminal pressure due to autoregulation. Moreover, flow may be permanently decreased following cerebral infarction, even if the arterial anatomical conditions have resumed their normal state because of the decreased metabolic demand of an infarcted area. Measurement of the regional cerebral blood volume (rCBV) helps with the hemodynamic assessment of these conditions, since there is a linear and inverse relationship between intraarterial pressure and intracranial blood volume. In 24 patients exhibiting various carotid and ischemic brain lesions we studied both rCBF and rCBV. The latter is a comparative measure between hemispheres obtained by single photon emission tomography after autotransfusion of 99m Technetium labeled erythrocytes. There was no correlation between rCBF and clinical status, CT scan or arterial lesions. There was no correlation between rCBV and clinical status or CT scan. There was, however, an interesting correlation between rCBV and the severity of the arterial lesion. The rCBV was symmetrical in all patients with normal or moderately stenotic carotid arteries before and after operation. In some patients with severe unilateral stenosis or occlusion, there was a significant relative increase of rCBV in the hemisphere downstream from the lesion, which disappeared after surgery (endarterectomy or extra-intracranial bypass). In some patients with severe and bilateral carotid lesions, we noted an asymmetry in rCBV that disappeared after a unilateral operation. Other patients with similar lesions develop asymmetry only after an operation that resulted in a relative increase in rCBV in the hemisphere supplied by the non-operated artery. In conclusion analysis of these results suggests that in this series of patients, rCBV modifications were the consequence of cerebral autoregulation distal to the arterial lesions and provided satisfactory assessment of hemodynamic improvement after surgical repair.     

Staged coronary artery bypass grafting after percutaneous angioplasty for intracranial vascular stenosis

OBJECTIVE: Cerebrovascular disease is commonly associated with coronary artery disease and is a major risk factor for cardiac surgery. Concomitant coronary artery bypass grafting and carotid endarterectomy may reduce the risk of stroke; however, this staged operation is effective only for extracranial lesions. The strategy for on-pump coronary artery bypass grafting for patients with intracranial vascular stenosis is still controversial. METHODS: The subjects were 157 consecutive candidates for coronary artery bypass grafting who underwent computed tomography and digital subtraction cerebral angiography preoperatively to check for cerebrovascular disease. Additional single-photon emission computed tomography was performed to evaluate cerebral ischemia, according to the neurologist's request. Patients with diffuse intracranial vascular stenosis impossible to treat with percutaneous transluminal angioplasty underwent off-pump coronary artery bypass grafting. Patients with a circumflex coronary artery lesion first underwent percutaneous transluminal angioplasty for cerebral vascular stenosis followed by secondary on-pump coronary artery bypass grafting. RESULTS: Three patients were selected for staged operations. Percutaneous transluminal angioplasty was performed for 4 intracranial stenotic lesions. All lesions were dilated successfully, and no complications developed during or after the procedure. All patients tolerated staged coronary artery bypass grafting and were extubated within 1 day without any mental disturbance. No further neurologic complication occurred, and computed tomography performed postoperatively revealed no significant changes. CONCLUSION: Staged on-pump coronary bypass after percutaneous transluminal angioplasty for cerebrovascular disease may reduce the risk of stroke during cardiopulmonary bypass, and it is useful especially in patients with intracranial cerebrovascular disease.     

Follow-up of renal artery stenosis by duplex ultrasound

We have previously shown that duplex ultrasound is an accurate method of diagnosing renal artery stenosis (93% accuracy compared with angiography in the diagnosis of less than 60% stenosis, 60% to 99% stenosis, or occlusion). With this method we have now serially observed 35 renal arteries with 60% to 99% renal artery stenosis in 27 patients. Nineteen stenotic renal arteries in 15 patients were observed without intervention. There was a significant decrease in kidney size (mean difference - 1.0 cm; p less than 0.01; mean follow-up 13 months) but all 19 renal arteries remained patent. Percutaneous transluminal angioplasty (PTA) was performed in five patients (six renal arteries) for renovascular hypertension. Renal duplex scanning documented relief of renal artery stenosis in two patients whose hypertension improved after PTA and confirmed residual 60% to 99% renal artery stenosis in three patients whose hypertension did not improve after PTA (mean follow-up 6.5 months). Aortorenal bypass was performed for 10 stenotic renal arteries in seven patients. At a mean follow-up of 9 months duplex ultrasound documented eight patent and two occluded aortorenal bypass grafts. Duplex ultrasound is useful both for defining the natural history of untreated renal artery stenosis and assessing the results of renal artery angioplasty or bypass.     

Endoscopic saphenous vein graft harvest for extracranial-intracranial bypass procedures

BACKGROUND: The introduction of endoscopic harvest of saphenous vein grafts (SVGs) for coronary artery bypass procedures over the past few years has reduced the morbidity and enhanced patient satisfaction associated with this procedure. This report introduces the use of the endoscopic SVG harvest for extracranial-intracranial (EC-IC) bypass procedures. METHODS: Endoscopic SVG harvest has been performed in more than 4000 patients at Duke University Medical Center from 1998 to 2003. We have performed 4 such procedures for EC-IC bypass, including 3 for the treatment of large or giant cerebral aneurysms and 1 for symptomatic middle cerebral artery occlusion. A 2-cm transverse incision is made to harvest 25- to 30-cm segment of SVG using a VasoView graft harvest system (Guidant Cardiac and Vascular Surgery, Menlo Park, CA). Skin closure was performed using a 4-0 Vicryl subcuticular stitch. RESULTS: Endoscopic SVG harvest was possible in each of the 4 patients. No graft leaks were visualized microscopically with infusion pressure testing of the graft before graft anastomosis, and no postoperative graft harvest complications (infection, hematoma, dehiscence, etc) were encountered in either the immediate or long-term follow-up (mean, 14 months). CONCLUSIONS: The use of endoscopic SVG harvest presents an attractive alternative to open SVG harvest for EC-IC bypass procedures. A high-quality long graft may be harvested with apparent decreased morbidity via this minimally invasive technique.     

Rupture of a giant carotid aneurysm after extracranial-to-intracranial bypass surgery

We report a case of a fatal rupture of a previously unruptured giant aneurysm of the bifurcation of the internal carotid artery (ICA), which occurred after an extracranial-intracranial (EC-IC) bypass and the partial occlusion of the ICA. Interim angiography showed retrograde filling of the proximal middle cerebral artery to the aneurysm. There have been four previously reported cases of giant aneurysms rupturing after treatment with an EC-IC bypass and carotid ligation, and it appears likely that a change in pressure/flow dynamics produced by the bypass may have been the cause. The technique of carotid ligation with an EC-IC bypass is used frequently to treat unclippable intracranial aneurysms, and the resulting hemodynamic changes need to be considered carefully to prevent this type of complication. To minimize hemodynamic stress on the aneurysm, we suggest that 1) the bypass caliber should be as small as possible consistent with sufficient cerebral blood flow after ICA occlusion, and 2) complete ICA occlusion should be performed as soon as possible after the bypass.     

Spontaneous intracranial internal carotid artery dissection treated by intra-arterial thrombolysis and superficial temporal artery-middle cerebral artery anastomosis in the acute stage--case report--

A 22-year-old man presented with sudden onset of right retro-orbital headache followed by left hemiparesis. Right carotid angiography demonstrated almost total occlusion of the intracranial internal carotid artery (ICA) and severe stenosis of the middle cerebral artery (MCA), presumably caused by arterial dissection. Local arterial injection of urokinase was performed 2 hours after onset. The ICA became patent, but the M2 portion of the MCA was still occluded, and the left hemiparesis did not improve. Superficial temporal artery-MCA anastomosis was immediately performed. The left hemiparesis disappeared completely 6 days after this procedure. Angiography 2 weeks after the onset revealed occlusion of the ICA, and maintenance of blood flow to the right cerebral hemisphere via the anastomosis. Magnetic resonance imaging showed small infarcts in the right cerebral cortex. Repeat angiography after 5 months showed recanalization of the right ICA and the right MCA. Combination of thrombolytic therapy and bypass surgery may be a useful treatment option for patients with sudden occlusion of the intracranial artery caused by dissection.     

EC-IC bypass surgery using a long vein graft--reconstructive procedures for the occluded long vein grafts

EC-IC bypass using a long vein graft has an advantage creating a large amount of blood flow immediately after the anastomosis, but on the other hand, disadvantage of relatively frequent incidence of the vein graft occlusion. In this report, we present three kinds of reconstructive operative procedures for the stenotic or occluded long vein grafts. Type A: A long vein graft bypass between external carotid and posterior cerebral artery was found occluded intraoperatively by the thrombosis occurred where the vein graft was injured during harvesting. Reconstruction was made simply by resecting the occluded segment of the graft and end-to-end suturing. Type B: A long vein graft used in subclavian artery-middle cerebral artery bypass was occluded three days postoperatively at the supraclavicular fossa by bleeding from the anastomosis site. The vein graft was found compressed and thrombosed. We reconstructed the occluded bypass by resecting the occluded supraclavicular segment and interposing a short vein graft with end-to-end anastomosis. Then, thrombectomy of the remaining vein graft was followed. Type C: A long vein graft used in external carotid-middle cerebral artery bypass stenosed at the anastomosis site with the external carotid artery a day after the operation. The stenotic bypass was successfully reconstructed by bridging a new short vein graft from another portion of the external carotid artery on the long vein graft distal to the stenotic site. All the long vein grafts we have done reconstructive surgery have been working well one to four years follow-up periods. So, we conclude that whenever a long vein graft occludes it should be reconstructed promptly before the vein graft becomes necrotic.     

Intraoperative control of extracranial-intracranial bypass patency by near-infrared indocyanine green videoangiography

OBJECT: Recently, intraoperative fluorescence angiography in which indocyanine green (ICG) is used as a tracer has been introduced as a novel technique to confirm successful aneurysm clipping. The aim of the present study was to assess whether ICG videoangiography is also suitable for intraoperative confirmation of extracranial-intracranial bypass patency. METHODS: Forty patients undergoing cerebral revascularization for hemodynamic cerebral ischemia (11 patients), moya-moya disease (18 patients), or complex intracranial aneurysms (11 patients) were included. Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery was performed 35 times in 30 patients (five patients with moyamoya underwent bilateral procedures), STA-posterior cerebral artery bypass surgery in two patients, and saphenous vein (SV) high-flow bypass surgery in eight patients. In each patient, following the completion of the anastomosis, ICG (0.3 mg/kg body weight) was given systemically via an intravenous bolus injection. A near-infrared light emitted by laser diodes was used to illuminate the operating field and the intravascular fluorescence was recorded using an optical filter-equipped video camera. The findings of ICG videoangiography were compared with those of postoperative digital subtraction (DS) or computerized tomography (CT) angiography. In all cases excellent visualization of cerebral arteries, the bypass graft, and brain perfusion was noted. Indocyanine green videoangiography was used to identify four nonfunctioning STA-MCA bypasses, which could be revised successfully in all cases. In two cases of SV high-flow bypasses, ICG videoangiography revealed stenosis at the proximal anastomotic site, which was also revised successfully. In all cases the final findings of ICG videoangiography could be positively validated during the postoperative course by performing DS or CT angiography. CONCLUSIONS: Indocyanine green videoangiography provides a reliable and rapid intraoperative assessment of bypass patency. Thus, ICG videoangiography may help reduce the incidence of early bypass graft failure.