Ability of commercial demineralized freeze-dried bone allograft to induce new bone formation is dependent on donor age but not gender

OBJECTIVE: To describe the clinical features of patients with occlusive disease of the proximal (V1) segment of the vertebral artery. DESIGN AND PATIENTS: Patients with either occlusion or high-grade stenosis involving the V1 segment were chosen for study from the New England Medical Center Posterior Circulation Registry. The registry is a consecutive series of patients with signs and symptoms of posterior circulation ischemia seen at the New England Medical Center, Boston, Mass, during a 10-year period. Clinical features, radiographic findings, and patient outcome were reviewed. RESULTS: Of the 407 patients in the registry, 80 (20%) had V1 segment lesions. Patients could be classified into 5 groups: (1) V1 disease and coexistent severe intracranial occlusive disease of the posterior circulation (n=22); (2) V1 disease with evidence of artery-to-artery embolism (n=19); (3) suspected V1 disease with artery-to-artery embolism, but with other potential causes of stroke or less certain vascular diagnosis (n=20); (4) V1 disease associated with hemodynamic transient ischemic attacks (n=13); and (5) proximal vertebral arterial dissection (n=6). Hypertension, cigarette smoking, and coronary artery disease were common risk factors. Clinical features, location of infarct, and outcome differed between groups and reflected the presumed mechanisms of stroke. CONCLUSIONS: Occlusive disease involving the V1 segment of the vertebral artery is common in patients with posterior circulation ischemia, but is often associated with other potential mechanisms of stroke. However, in a series of patients seen at a tertiary referral center, occlusive disease of the V1 segment was the primary mechanism of ischemia in 9% of patients.     

Progressive intracranial occlusive disease associated with deficiency of protein S. Report of two cases

BACKGROUND AND PURPOSE: Deficiency of the free fraction of protein S has been associated with arterial or venous stroke. The pathogenesis of vascular occlusion in patients with protein S deficiency is not known. We present two cases of cerebral infarction and deficiency of protein S in which the subjects had progressive intracranial occlusions. CASE DESCRIPTION: A 16-year-old girl was admitted because of left brain stem infarction and protein S deficiency. Cerebral angiography disclosed stenosis of the right intracranial vertebral artery and occlusion of the left posterior cerebral artery. A second angiogram performed 18 months later disclosed occlusion of the right vertebral intracranial artery. In the second case, a 17-year-old girl was admitted because of left hemispheric cerebral infarction and protein S deficiency. Cerebral angiography showed stenosis of the left anterior cerebral artery, left supraclinoid internal artery, and left middle cerebral artery. A second cerebral angiogram performed 5 months later disclosed occlusion of the left anterior cerebral artery and poor hemispheric perfusion through the left middle cerebral artery. CONCLUSIONS: Based on our cases, we postulate that some patients with prothrombotic states may develop progressive intracranial arterial occlusions, possibly secondary to a permanent thrombogenic stimulus. We suggest routinely searching for prothrombotic states in young patients with intracranial occlusion, especially if the occlusion is progressive and other causes are not obvious.     

Cerebral revascularization using muscle free flap for ischemic cerebrovascular disease in adult patients

The efficacy of encephalo-myo-synangiosis (EMS) using muscle free flap was evaluated for the treatment of ischemic cerebrovascular disease in adult patients. Three patients with adult moyamoya disease and three patients with atherosclerotic ischemic cerebrovascular disease were treated. EMS used four latissimus dorsi muscles and two serratus anterior muscles. Postoperative selective angiography showed collateral circulation from the transferred muscle to the brain in four of the six patients. The other two patients showed patent nutrient artery of the transferred muscle flap. Cerebral blood flow study disclosed postoperative improvement of perfusion reserve capacity in all sides. One patient suffered a perioperative stroke by hemoconcentration due to poor control of diabetes mellitus. The mean follow-up period was 23 months. EMS using muscle free flap is a possible procedure in selected patients with impaired cerebral perfusion reserve capacity due to multiple stenosis or occlusion of cerebral arteries including moyamoya disease or who required cerebral blood flow augmentation in the anterior and/or posterior cerebral artery territories due to internal carotid artery occlusion.     

Neural activation of the brain with hemodynamic insufficiency

Little is known about how ischemia affects hemodynamic responses to neural activation in the brain. We compare the effects of a motor activation task and a cerebral vasodilating agent, acetazolamide (ACZ), on regional cerebral blood flow (rCBF) in primary sensorimotor cortex (PSM) in six patients with major cerebral artery steno-occlusive lesions without paresis of the upper extremities. Quantitative rCBF was measured in all patients using H2(15)O autoradiographic method and positron emission tomography. The CBF was determined at rest, during a bimanual motor activation task, and 10 minutes after ACZ administration. With bimanual motor activation, rCBF increased significantly in both PSM compared with at rest (P < 0.01 on lesion side, and P < 0.02 on contralateral side). However, rCBF did not increase after ACZ injection in the PSM on the lesion side, whereas rCBF increased significantly in the contralateral PSM after ACZ injection compared with the level at rest. This result suggests that despite a decreased hemodynamic reserve, there is a nearly normal flow response to neural activation, indicating that the mechanism of vasodilation responsible for perfusion change is different for acetazolamide and neural activation. The relations among neural activation, hemodynamic status, and cerebral metabolism in the ischemic stroke patients are discussed.     

Prescribing of antacids and ulcer-healing drugs in primary care in the north of England

Seventeen patients, 14 males and 3 females, mean age 64 years (range 45-77 years) with longstanding unilateral occlusion of the internal carotid artery and minimal neurological deficit, were evaluated in order to find criteria for potential benefit of extracranial-intracranial by-pass surgery. 3-D transcranial Doppler was used for estimation of mean velocities and pulsatility index in the middle cerebral artery, anterior cerebral artery and posterior cerebral artery before and after iv injection of 1 g acetazolamide. The anterior cerebral artery was the supplying vessel to the occluded side in 16 patients and mean velocities were significantly (p < 0.001) faster on the occluded (59.3 +/- 14.5 cm sec-1) and nonoccluded (91.6 +/- 29.6 cm sec-1, p < 0.05)) side than those found in the middle cerebral artery (39.2 +/- 13.7 and 50.9 +/- 8.5 cm sec-1). In two patients a decrease of mean velocity after acetazolamide was noted in middle cerebral artery indicating 'steal' effect. In another 4 patients, poor vasomotor response was seen with less than 11% of mean velocity increase in the middle cerebral artery. Differences between posterior cerebral artery on the occluded and nonoccluded side were insignificant as well as those between middle and posterior on the occluded side. Resting values of pulsatility index differed significantly (p < 0.01) only between anterior and posterior cerebral artery on the nonoccluded side.(ABSTRACT TRUNCATED AT 250 WORDS)     

Magnetic resonance angiography in patients with acute stroke treated by local thrombolysis

Although magnetic resonance angiography (MRA) is accepted for showing chronic intracranial stenotic or occlusive lesions, the method has not been practically examined in patients with acute cerebral ischaemia. We carried out three-dimensional time-of-flight MRA in six patients with acute ischaemia treated by local thrombolysis, and compared the findings with those of digital subtraction angiography (DSA). In all patients, MRA before thrombolysis clearly demonstrated the occluded arteries, which corresponded precisely to those shown by DSA. In four patients with complete recanalisation of the occluded vessels after thrombolysis, the recanalisation could be demonstrated by postoperative MRA. In one patient with reocclusion of the recanalised artery, repeat MRA also demonstrated the reocclusion, confirmed by DSA. These results suggest that MRA may be helpful for noninvasive investigation before and after thrombolysis.     

Race and sex differences in the distribution of cerebral atherosclerosis

BACKGROUND AND PURPOSE: The purpose of this study was to assess the influence of race, sex, and other risk factors on the location of atherosclerotic occlusive lesions in cerebral vessels. Previous angiographic studies of patients with stroke or transient ischemic attack (TIA) suggest that extracranial atherosclerosis is more common in whites and intracranial disease is more common in blacks. Noninvasive techniques such as duplex ultrasound, transcranial Doppler (TCD), and magnetic resonance angiography (MRA) allow vascular assessment of a more representative proportion of patients than does conventional angiography alone. METHODS: Consecutive patients evaluated at a community hospital for stroke or TIA over a 2-year period were reviewed. Lesions were defined as a 50% or greater atherosclerotic stenosis by angiography, duplex ultrasound, or TCD, or a moderate stenosis by MRA. RESULTS: Whites were more likely than blacks to have extracranial carotid artery lesions (33% versus 15%, P = .001), but the proportion of patients with intracranial lesions was similar (24% versus 22%). Men were more likely to have intracranial lesions than women (29% versus 14%, P = .03). When multivariate logistic regression analysis was used, white race was the only predictor for extracranial carotid artery lesions, and male sex was the only predictor for intracranial lesions. The cause of stroke/TIA was extracranial carotid artery disease in 8% and intracranial disease in 8% of all patients in the study. CONCLUSIONS: The distribution of cerebral atherosclerosis is influenced by race and sex but not by other vascular risk factors. In our patient population, intracranial disease is as common a cause of cerebral ischemia as extracranial carotid disease.     

Doppler sonography diagnosis of restenosis after percutaneous transluminal angioplasty: sensitivity and specificity of the pedal-brachial index in relation to changes in absolute arterial blood pressure

INTRODUCTION: Percutaneous transluminal angioplasty (PTA) is accepted for the treatment of patients with severe, disabling claudication who fail conservative management and also for patients with limb threatening ischaemia [1-5, 18, 20]. The development of neointimal hyperplasia (predominantly during the first 6-12 months after PTA), and the progression of the underlying atherosclerotic disease (thereafter), are the reasons of restenosis and reocclusion [1-4, 6]. More than 50% of occurring restenoses are primarily oligo/asymptomatic [1-4, 6-10, 25, 26]. Follow-up visits are aimed at detecting significant restenoses, before reocclusion occurs, so that timely reintervention is possible. In asymptomatic patients in whom reintervention is not necessary, repeated angiography is not justifiable. Non-invasive alternatives include Duplex scanning or the assessment of simple peripheral haemodynamic variables such as ankle systolic pressures and the ankle/brachial pressure index (ABI). The aim of this study was: (1) To determine the sensitivity and specificity of post PTA changes in the ABI, and changes in the absolute ankle pressure to detect restenoses after femoropopliteal PTA (as a gold standard, Duplex scanning, with its reported high sensitivity, specificity and accuracy for detecting restenosis was chosen [9, 25]. (2) For both methods, to evaluate the criteria (minimal magnitude of change-cut off points) necessary to detect restenosis with reasonable reliability. (3) To compare the diagnostic value of changes in ABI to changes in absolute ankle pressure, and to determine the method of preference for detection of post-PTA restenosis. MATERIAL AND METHODS: The study included 171 consecutive patients with peripheral arterial occlusive disease, Fontaine stage II or stage III, selected for femoro-popliteal PTA. All pts presented with single or multiple arterial stenoses or occlusions not exceeding 10 cm of length within the femoro-popliteal segment. At least one lower leg artery had to be patent. Only pts in whom PTA was successful (maximum residual lesion within the dilated segment showed < or = 30% diameter reduction (DR)) were accepted for a 12-month follow-up. After PTA all patients were prescribed a platelet aggregation inhibitor. The investigational scheme included the following procedures: 1. Duplex scanning of the entire lower leg vascular tree before PTA, within 7 days after PTA as well as at 4 weeks and at 12 months. 2. Scoring of Duplex results using the Bollinger angiography score system [11] which distinguishes the pelvic segment, a proximal and a distal superficial femoral segment, the popliteal artery including the popliteal trifurcation and the proximal 1/3 of the lower leg arteries. The score system allows the differentiation of single and multiple plaque (< or = 25% DR), single or multiple stenoses (< or = 50% and < or = 50% DR) involving less or more than 50% of the segment under investigation as well as short (< 50% of segment length) and long (> or = 50% of segment length) vascular occlusions. 3. The assessment of the resting ankle systolic pressures (dorsalis pedis artery, posterior tibial artery) of the reference leg, pre PTA, at 4 weeks, and 3, 6, 9 and 12 months using a 8 Mhz CW Doppler device (Parks 908) with the patient in the supine position and after a resting period of > or = 30 minutes. 4. The calculation of the ankle/brachial pressure index (ABI) as the ratio of the higher systolic pressure value from either the posterior tibial or the dorsalis pedis artery divided by the higher value of the two (bilateral) systolic brachial pressures. 5. A full physical examination including a pulse status, vascular auscultation as well as the assessment of the clinical symptomatology pre PTA, at 4 weeks as well as at 6 and 12 months. The following findings were suggestive of restenosis/reocclusion of the dilated segment. 1. Reoccurrence of a stenosis < or = 50% DR within the dilated segment and/or its inflow or outflo     

High-flow bypass using nonocclusive excimer laser-assisted end-to-side anastomosis of the external carotid artery to the P1 segment of the posterior cerebral artery via the sylvian route. Technical note

In a patient with a giant aneurysm of the basilar artery trunk, a vein graft was interposed between the external carotid artery in the neck and the P1 segment of the posterior cerebral artery. Balloon occlusion of both vertebral arteries was performed 3 days later. The sylvian route was used for the grafting procedure and the connection to the posterior cerebral artery was made by using the excimer laser-assisted nonocclusive anastomosis technique.     

Fibroblast growth factor-9 (glia-activating factor) stimulates proliferation and production of glial fibrillary acidic protein in human gliomas either in the presence or in the absence of the endogenous growth factor expression

BACKGROUND AND PURPOSE: A favorable risk-benefit ratio for warfarin compared with aspirin has been reported for the prevention of major vascular events in symptomatic >/=50% intracranial stenoses. Transcranial color-coded duplex sonography (TCCS) criteria providing an accurate detection of >/=50% and <50% stenoses of the anterior, middle, and posterior cerebral arteries and basilar and vertebral arteries were evaluated retrospectively with angiography used as the standard of reference. METHODS: Prospectively collected TCCS, extracranial color-coded duplex sonography, and intra-arterial digital subtraction angiography data of 310 patients were reviewed. The patients had angiography for confirmation of symptomatic extracranial >/=70% carotid stenoses, symptomatic stenoses (peak systolic velocity higher than the corresponding mean value +2 SDs of 104 normal subjects), and occlusions of the middle cerebral or basilar artery previously assessed by ultrasound. The sonographer was not aware of angiographic findings. RESULTS: TCCS would have detected all 31 of >/=50% intracranial stenoses with 1 false-positive and 35 of 38 <50% stenoses with 3 false-positives. One of 69 stenoses (1%) and 280 of 2741 normal arteries (10%) were missed because of inadequate insonation windows. The corresponding peak systolic velocity cutoffs for >/=50%/<50% stenoses were >/=155/>/=120 cm/s (anterior cerebral artery), >/=220/>/=155 cm/s (middle cerebral artery), >/=145/>/=100 cm/s (posterior cerebral artery), >/=140/>/=100 cm/s (basilar artery), and >/=120/>/=90 cm/s (vertebral artery). CONCLUSIONS: TCCS may reliably assess >/=50% and <50% basal cerebral artery narrowing and prove useful for noninvasive management of patients with symptomatic intracranial stenoses.     

Angioplasty of the occluded internal carotid artery

PURPOSE: To review patients who have presented with acute strokes from a middle cerebral artery occlusion in whom in addition to the middle cerebral artery thromboembolus, an internal carotid artery occlusion has been present, and in whom angioplasty of these totally occluded internal carotid arteries has bee n successful. METHODS: We reviewed retrospectively our experience in treating a cute stroke patients with intracranial, intraarterial urokinase. Six of 27 patients had internal carotid artery occlusions in addition to middle cerebral artery occlusions. Two patients presented with spontaneous carotid dissections for wh ich no further intervention from the ipsilateral internal carotid artery was attempted. In the remaining four internal carotid artery occlusions secondary to atherosclerotic disease, standard guide wires and catheters were negotiated across the level of the internal carotid artery occlusion, which expedited intracranial catheterization for thrombolysis. Subsequently, angioplasty of the internal carotid artery was performed. RESULTS: All four occluded internal carotid arteries could be traversed. No new neurologic deficits occurred. No vascular injuries occurred. No deaths occurred. Four- to 6-month follow-up showed all four internal carotid arteries remained patent. CONCLUSION: In acute occlusions of the internal carotid artery from atherosclerosis, the occluded vessel can sometimes be recanalized with low morbidity. In addition, endovascular access to the intracranial circulation can be expedited by using the recanalized internal carotid artery.     

Pathophysiologic studies of the pulmonary and coronary circulations in man

Studies of the pulmonary circulation in normal man, performed with external radiation detectors, have shown that pulmonary blood volume is about 10% of total blood volume. Pulmonary blood volume was unchanged in patients with acute or chronic left atrial hypertension and in normal persons during expansion of total blood volume in spite of marked increases in pulmonary vascular pressures. However, pulmonary blood volume was greatly increased in patients with polycythemia rubra vera and a large total blood volume and in patients with a left to right shunt but normal pulmonary intravascular pressure. Studies of regional myocardial perfusion with injection of xenon-133 solution into the left coronary artery revealed localized areas of ischemia distal to stenotic lesions even when the patient was at rest. During angina produced by pacing, more severe ischemia occurred, thus suggesting that functional factors reduce local perfusion below resting levels. In patients with "variant" angina, intravenous injection of thallium-201 chloride during spontaneous attacks has revealed large cold areas in myocardial scintigrams not present under control conditions, thus suggesting severe transmural reduction of perfusion in heart muscle corresponding to S-T segment elevation in the electrocardiogram.     

Contribution of transcranial color-coded real-time sonography to the etiopathogenetic classification of middle cerebral artery stenosis

Transcranial color-coded real-time sonography (TCCS) and cranial computed tomography were applied to patients with middle cerebral artery (MCA) stenosis to evaluate whether these techniques may disclose additional aspects of the pathophysiology of the stenotic lesion. In 15 patients with MCA stenosis identified by transcranial Doppler sonography, the echogenicity of the stenotic segment was estimated subjectively by TCCS. The density of the stenotic segment, prior to being detected by TCCS, was quantified by computed tomography. In 5 of the 15 patients, transcranial image-directed Doppler sonography identified a hyperechogenic lesion in association with the stenotic vascular segment; computed tomography demonstrated a "dense" artery (Hounsfield units [HU] > 120) in the corresponding vascular segment. In 10 patients the echogenicity of the stenotic segment was found to be normal, with a computed tomography density of < 100 HU in the corresponding segment. Hyperechogenic and hyperdense stenotic vascular segments in TCCS and computed tomography, respectively, may indicate an arteriosclerotic vascular lesion with calcium deposits. Normal echogenicity and normal to slightly elevated computed tomography-density of a stenotic vascular segment may suggest the presence of a thrombotic/embolic lesion.     

Endovascular surgical approach to intracranial vascular diseases

PURPOSE: The endovascular surgical approach to complex disorders of the central nervous system has made rapid and significant advancements over the past decade. Patients with intracranial arterial aneurysms, traumatic carotid and vertebral artery lesions, including fistulas and pseudoaneurysms, hemodynamically significant atherosclerotic lesions, vasospasm, and acute stroke are now being approached and treated by newer and less invasive techniques, including cerebral angioplasty and thrombolytic therapy. METHODS: All procedures are usually performed from a transfemoral approach utilizing a variety of occlusion devices, including detachable silicone balloons, microcoils, electrolytic detachable coils, liquid tissue adhesives, and particulate emboli for vessel occlusion. For dilatation and reperfusion of vessels, balloon angioplasty catheters, stents, and thrombolytic drugs are being used. RESULTS: For the treatment of traumatic vascular injuries, such as carotid cavernous sinus fistulas and vertebral arteriovenous fistulas and pseudoaneurysms, endovascular therapy has become the treatment of choice. The endovascular approach for intracranial aneurysms is emerging as a therapeutic option in selected cases. For occlusive disorders in patients presenting with acute cerebral ischemia, extracranial angioplasty and cerebral thrombolysis techniques are currently under investigation. CONCLUSIONS: As these techniques continue to evolve, the field of interventional neuroradiology will expand the therapeutic options for managing complex cerebrovascular disorders and improve patient outcome in acute stroke therapy.     

Vasoreactive effect of acetazolamide as a function of time with sequential PET 15O-water measurement

The accurate assessment of vascular flow reserve is crucial for the evaluation of risk among patients with cerebrovascular disease. In six patients with unilateral occlusion of the internal carotid artery and one patient with unilateral occlusion of the middle cerebral artery (mean +/- S.D. age = 68 +/- 3 years), we measured cerebral blood flow (CBF) after the administration of 940 MBq 15O-water using a remotely controlled power injector. Studies were performed at rest, after 10 min, and then 10, 20 and 30 min after the administration of 1 mg acetazolamide to evaluate the vasoreactive effect, as reflected by an increase in CBF. Sixteen regions of interest (ROIs) were drawn over the CBF images. These ROIs were as follows in each hemisphere: Area I, four areas in the cortical middle cerebral arterial territory (superior frontal, frontal, temporal and parietal areas); Area II, four areas of the deep middle cerebral and vertebral arterial territory (occipital area, basal ganglia, thalamus and cerebellum). Taking normalized resting CBF to be 100%, the mean CBF measured 10, 20 and 30 min post-injection using sequential positron emission tomography was as follows: Area I, 141.4 +/- 16.3, 127.7 +/- 15.3 and 128.2 +/- 17.4% for non-occluded sites and 116.3 +/- 22.8, 112.7 +/- 16.4 and 114.9 +/- 17.1% for occluded sites; Area II, 143.4 +/- 14.5, 126.2 +/- 10.4 and 125.0 +/- 12.9% for non-occluded sites and 141.9 +/- 28.9, 126.0 +/- 20.5 and 124.1 +/- 17.1% for occluded sites. A significant difference in mean CBF was noted between the non-occluded and occluded sites in Area I, the most marked difference of 25.1% being observed 10 min after the administration of the acetazolamide. We conclude that for an accurate assessment of vascular reserve in patients with cerebrovascular disease, CBF should be measured 10 min post-administration of the acetazolamide.     

The hemodynamics and anatomy of the circle of Willis. The technic and clinical value of selective MR angiography

This study evaluates the usefulness of MR angiography in analysing the individual collateral flow dynamics and anatomy of the circle of Willis in 56 patients with high-grade extracranial carotid stenosis or occlusion. Selective MRA of the carotid or vertebrobasilar area was performed by means of presaturation up to the brain-supplying arteries at the level of the middle neck (angled presaturation slabs). Results obtained with selective and non-selective MRA in 56 consecutive patients were compared with the findings at transcranial Doppler ultrasonography and arterial angiography. Ischaemic cerebral infarctions were classified by computerized tomography and correlated with the results of collateral flow analysis: Sensitivity of selective MRA in detecting intracranial collateral flow via anterior or posterior communicating artery was 96 and 97%, respectively; sensitivity in depicting extracranial transorbital flow was lower (71%). Non-selective MRA was 100% sensitive in detecting a non-filling of the horizontal (A1) segment of the anterior cerebral artery and in identifying an origin of the posterior cerebral artery from the intracranial carotid artery. Slow flow infarctions occurred more frequently in patients with transorbital and posterior-to-anterior collateral flow than in patients with collateral flow via anterior communicating artery.     

Vascular distribution of paradoxical emboli by transcranial Doppler

BACKGROUND AND PURPOSE: Paradoxical embolism through a patent foramen ovale is a contributory mechanism to stroke and may be diagnosed by contrast echocardiography. The intracranial distribution of these emboli has not been previously reported. METHODS: We used transcranial Doppler combined with agitated saline contrast injection to determine whether there was a preferential distribution of the contrast into the anterior or posterior intracranial circulation of patients with an acute stroke or transient ischemic attack. RESULTS: Forty-nine patients were studied--27 men and 22 women, with a mean age of 62.7 +/- 13.3 years (range, 29 to 85 years). Microcavitations were detected in the proximal right middle cerebral artery in 12 of 49 patients (24%). A patent foramen ovale was confirmed in all cases by simultaneous transesophageal echocardiography. Of the 12 patients, microcavitations were also detected in the proximal basilar artery in nine (75%). CONCLUSIONS: While paradoxical embolism appears to occur more frequently in the anterior circulation, the high rate of detection of microcavitations in the basilar artery suggests that paradoxical embolism to the posterior intracranial circulation may be more frequent than generally believed.     

Bypass surgery for vascular disease of the carotid system

A series of 58 operations on 56 patients, in whom a branch of the superficial temporal artery was anastomosed to a branch of the middle cerebral artery (STA-MCA bypass or Yasargil procedure), is reviewed. These operations were performed chiefly for occlussions or for inaccessible stenotic lesions of the internal carotid or middle cerebral arteries. Patency in eight patients operated on from April 1971 through November 1973 was low (25%). Patency in patients operated on since July 1974 has been high (95%). There have been no deaths and no major ischemic strokes attributable to the surgery. The rationale for this procedure is considered in relationship to the anatomy and physiology of the cerebral circulation and the pathogenesis of syndromes of cerebral ischemia. The operation appears to have a low morbidity in good-risk patients. The role of this operation in managing common manifestations of cerebral vascular disease such as focal transient cerebral ischemic attacks (TIAs) and amaurosis fugax, although not fully established, appears encouraging. The procedure seems useful for orthostatic cerebral ischemia caused by multiple occlusions of major extracranial (and intracranial) vessels and, occasionally, for progressing strokes related to internal carotid artery occlusion, both of which are relatively uncommon manifestations of cerebral vascular occlusive disease. It may have application in the rare "slow stroke." The procedure is probably of limited value, if any, in the management of large completed infarcts but may be indicated in selected patients with small infarctions who have preserved most of their cerebral function and who have had evidence of subsequent focal ischemic events. The procedure is useful for bypassing giant aneurysms or basofrontal tumors invading major vessels. It may have a role in the management of fibromuscular disease of the internal carotid artery.     

Asymptomatic occlusive lesions of carotid and intracranial arteries in Japanese patients with ischemic heart disease: evaluation by brain magnetic resonance angiography

BACKGROUND AND PURPOSE: The purpose of this study was to elucidate the prevalence and degree of asymptomatic occlusive lesions in the carotid and intracranial arteries in Japanese patients with ischemic heart disease (IHD). METHODS: We performed carotid and intracranial MR angiography (MRA) on 67 patients (49 men, 18 women; age range, 40 to 78 years; mean age, 60.1 years) who had received selective coronary angiography for the clinical diagnosis of IHD. On the basis of these images, degree of stenosis in the regions of the bilateral carotid artery bifurcation and five regions of the intracranial arteries, ie, bilateral intracranial portions of the internal carotid arteries and the middle cerebral arteries and the basilar artery were estimated. RESULTS: Stenosis of more than 25% narrowing of the diameter of the target arteries was found in 15 patients (22.4%) in the extracranial carotid arteries and in 11 patients (16.4%) in the intracranial arteries. Most of the stenotic lesions were mild. The incidence of extracranial carotid stenosis and the severity of coronary atherosclerosis showed a significant correlation. The mean age of the patients with intracranial arterial lesions was statistically higher than those without intracranial lesions. CONCLUSIONS: Our data suggest that asymptomatic occlusive lesions in the carotid and intracranial arteries are fairly common in Japanese patients with IHD, although the degree of stenosis is relatively mild. Coexistence of carotid atherosclerosis should be suspected in IHD patients with severe coronary atherosclerosis, and the possibility of atherosclerosis in the intracranial arteries should be considered in aged IHD patients.     

Persistent trigeminal artery: an anatomic study

INTRODUCTION: The most frequent embryonic communication between the vertebrobasilar and carotid systems is a persistent trigeminal artery (PTA). It has been observed in 0.1 to 0.2% of cerebral angiograms. We found this variation in an anatomic specimen, and after microscopic dissection, we performed an analysis of the course of the PTA and its relationship with the abducens nerve and the meningohypophyseal trunk. METHOD: A PTA was incidentally encountered in an injected cadaver specimen during a transpetrosal approach. This embryonic variation and its anatomic relationship are discussed. RESULTS: The PTA can take either a lateral or medial course regarding its relationship with the abducens nerve. When the PTA originates from the posterolateral aspect of the posterior bend of the cavernous carotid artery (C4 segment), it crosses underneath and distorts the abducens nerve, continuing between the abducens and trigeminal nerves. When taking a medial course, the PTA arises from the posteromedial aspect of the posterior bend of the cavernous carotid at the same segment and pierces the clival dura at the dorsum sellae. Cranial nerve displacement or distortion is less likely in this variation. In an analysis of carefully described anatomic studies, the PTA and meningohypophyseal trunk were found arising from either common or separated origins. CONCLUSION: The most frequent embryological anastomosis between the carotid and vertebrobasilar system is the PTA. Its course and relationship with the cranial nerves may determine its clinical presentation.