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At least 91 records · Page 5Linked to original sources
PubMed1999

Attenuation of basilar artery spasm after experimental subarachnoid hemorrhage in rabbit by potassium channel activator cromakalim--a preliminary result.

Cerebral vasospasm associated with aneurysmal subarachnoid hemorrhage (SAH) remains a major complication in patients suffering from SAH. Regulation of membrane potential of arterial smooth muscle through activation or inhibition of potassium (K+) channel activity provides an important mechanism to dilate or constrict arteries. The present study examined the effect of a K+ channel activator, cromakalim, on cerebral vasospasm following experimental SAH. By the route of topical application and intra-arterial injection, basilar arteries were exposed transclivally and measured on-line using videomicroscopic camera. Continuous microinjection from right vertebral artery was given after the result of application was observed. Basilar artery spasm induced by SAH was released by topical or intra-arterial administration of cromakalim, and this beneficial effect against cerebral vasospasm was dose-dependent. There was no significant difference between topical and intra-arterial administration of cromakalim. These results indicate that K+ channel activator may play an important role for ameliorating cerebral vasospasm. An important goal of future studies will be to carefully evaluate the possibility and effect of intra-arterial administration of cromakalim to treat angiographic vasospasm.

Animals↗
PubMedDate not supplied

Directional C-W Doppler sonography in the diagnosis of basilar artery disease.

Using directional continuous-wave Doppler sonography of the vertebral arteries, we have investigated 1,540 patients during the past 5 years. On the basis of unilateral and bilateral retrograde brachial angiograms in the same patients (a total of 1,989 angiograms) we have developed sonographic criteria for demonstrating a significant increase in the peripheral resistance of both distal vertebral arteries and/or the basilar artery. All 11 cases of basilar artery stenosis of at least 60% reduction in lumen diameter (as shown by angiography) exhibited an approximately 40% or higher reduction in the sum of the modified Pourcelot indices of both vertebral arteries with respect to age-matched controls. All 3 stenoses of less than 60% reduction in lumen diameter were not detected by sonography. Even a good collateral circulation through rete mirabile anastomoses did not normalize the modified Pourcelot indices. One case of a persistent primitive trigeminal artery with thin-calibered vertebral arteries was also detected by sonography. The high percent of patients with one hypoplastic vertebral artery in the group with basilar artery stenoses indicates an increased risk for atherosclerosis of the basilar and/or distal vertebral artery in these patients. All 14 angiographically verified occlusions of the basilar artery were detected by sonographic criteria independent of the occlusion localization. Thus, we believe that directional continuous-wave Doppler sonography is a reliable technique for detecting basilar artery stenoses of at least 60% reduction in lumen diameter and basilar artery occlusions.

Arterial Occlusive Diseases↗
PubMed1998

[Intra-arterial fibrinolysis in acute thrombosis of the basilar artery].

INTRODUCTION: Ischemia in the territory of the basilar artery presents with a variable clinical picture of hemiparesia-tetraplegia, progressive deterioration of level of consciousness, irregular respiration and apnea leading to irreversible coma and death in between 75% and 86% of cases. The usual treatment is supportive. CLINICAL CASE: We present the case of a 49 year old woman with acute thrombosis of the basilar artery and a progressive course leading to coma. No bulbar lesions were seen on the CT scan done in the Emergency Department. Thrombosis of the basilar artery and permeable bilateral carotid systems were shown on arteriography. There were no contra-indications to fibrinolysis. Following local fibrinolytic treatment with urokinase the patient had full recovery from her neurological disorder and no sequelae. The basilar artery remained permeable six months later. CONCLUSIONS: Emergency treatment with cerebral intra-arterial fibrinolysis within the first six hours, in a case of neurological deficit progressing in the basilar artery territory, with persistence of brain-stem functions and no signs of decerebration (provided there are no contra-indications to fibrinolysis and the initial cerebral CT scan shows no bulbar lesions) may save the patient's life, with total or partial recovery of brain-stem function.

Acute Disease↗
PubMed1985

Extra-intracranial bypass surgery for vertebrobasilar insufficiency due to obstructive vertebral artery and vertebral-basilar artery junction disease.

This report is on 19 patients with vertebrobasilar insufficiency in whom direct extra-intracranial arterial bypass surgery to the posterior circulation was performed. In all patients preoperative angiography had demonstrated vascular lesions of haemodynamic significance of either one or both vertebral arteries (VA) or within the vertebral-basilar artery junction (VABAJ). The bypass procedure was performed between the occipital artery (OA) and - depending on the localization of the obstructive vascular lesion - the posterior inferior cerebellar artery (PICA), the VA or the anterior inferior cerebellar artery (AICA). A modification of the operative technique is presented with using a paramedian approach. The clinical results of this series support the concept that a patent extra-intracranial graft to the posterior circulation may have a protective effect by preventing further ischaemic events.

Adult↗
PubMed1991

Basilar artery occlusion in rats.

The basilar artery is one of the three major sources of blood supply to the circle of Willis. To investigate the effects of basilar artery occlusion, we surgically exposed and coagulated the basilar artery in 25 rats. Basilar artery occlusion at any single point between the foramen magnum and the circle of Willis in 11 rats did not produce histologically detectable infarcts in the brain at 12-24 hours. Two-point occlusions of the basilar artery in 12 rats produced variable infarcts between the occlusion sites but no ischemic lesions elsewhere. After either single- or double-point occlusions, the proximal basilar artery refilled within 2-3 minutes. When the basilar artery was occluded above and below the origins of the anterior inferior cerebellar arteries, the artery segments between the occlusion points initially collapsed but refilled within 2-3 minutes in two rats. Basilar artery occlusions invariably suppressed cortical somatosensory evoked potentials by greater than 50%. Regardless of whether a brain stem infarct developed, somatosensory evoked potential amplitudes recovered to greater than baseline levels by 4 hours in seven of 17 rats and returned to baseline levels by 24 hours in every rat tested. We conclude that the occluded basilar artery receives extensive retrograde collateral blood flow and that somatosensory evoked potentials are exquisitely sensitive to basilar artery occlusion but are insensitive to whether brain stem infarcts develop.

Animals↗
PubMed1985

Resolving occlusive lesions of the basilar artery.

Progression of severe basilar artery stenosis to occlusion is a well-recognized phenomenon, but regression of a severe basilar artery atherothrombotic lesion has not been described previously. In this report, two patients with a symptomatic severe basilar artery occlusive lesion showed substantial angiographic improvement after 3 months of anticoagulation in one case and 4 months after superficial temporal artery to superior cerebellar artery bypass in the other case. The findings in these cases indicate that clinical improvement in similar cases may reflect recanalization of a basilar artery occlusive lesion. The uncertain natural history and potential for regression of symptomatic basilar artery atherothrombosis make us hesitant to recommend posterior circulation revascularization immediately after such lesions are first demonstrated angiographically.

Basilar Artery↗
PubMed1982

Lack of alpha-adrenoreceptor binding of [125I]BE2254 to rat basilar artery membranes.

Rat basilar arteries do not contain classical alpha- or beta-adrenoreceptors as assessed by electrophysiological techniques even though these arteries are innervated by catecholamine-containing perivascular nerves. These arteries were therefore examined for their ability to selectively bind an alpha-adrenoceptor radioligand, [125I]BE2254 (2/beta/4-hydroxyphenyl)-ethylaminomethyl)-tetralone). For comparison, rat tail arteries were also studied as these are known to contain functional alpha-adrenoreceptors. It was found that basilar artery membranes had only one-third of the specific binding of tail artery membranes and this finding collaborates the electrophysiological data.

Animals↗
PubMed1978

Models for investigating the aetiology of cerebral arterial spasm: comparative responses of the human basilar artery with rat colon, anococcygeus, stomach fundus, and aorta and guinea-pig ileum and colon.

1 The pharmacological similarity between human basilar artery and a number of isolated tissues (rat colon, anococcygeus, stomach fundus and aorta and guinea-pig ileum and colon) has been assessed during investigations of the aetiology of cerebral arterial spasm. 2 The responses of each of the six tissues to human normal and abnormal cerebrospinal fluid (CSF) and to human serum were compared with those of the human isolated basilar artery. 3 These studies revealed the presence of a vasodilator factor in CSF from subarachnoid haemorrhage patients and several tissues may be of use for further work in identifying the vasoactive substances in CSF. 4 No tissue displayed exactly the same spectrum of biological reactivity as the human basilar artery. The rat stomach fundus showed the closest similarity and was further studied for similarities in drug-induced responses. 5 The rat stomach fundus, like the human basilar artery, was contracted by 5-hydroxytryptamine, prostaglandin F2alpha and histamine and relaxed by dopamine. However, noradrenaline relaxed the fundus but contracted the basilar artery.

Animals↗
PubMed1995

Declining density of intimal smooth muscle cells and age as preconditions for atheronecrosis in the basilar artery.

The aging basilar artery has some differences and some similarities when compared with the aorta and coronary arteries. As the non-necrotic intimal thickness increases over time, the number of smooth muscle cells reaches a steady state around age 25-30 years in the coronaries and aorta, but continues to increase in the basilar artery, even to 90 years of age. The numbers of cells per unit of tissue (the cell density) declines with age, and the patterns of decline are quantitatively similar in all three arterial segments. All arteries so far examined behave alike in showing that atheronecrosis emerges in those specimens that have sufficiently low density of intimal smooth muscle cells. These results identify low intimal cell density as a criterion for recognizing arteries that are prone to atheronecrosis. One possible explanation is that depopulation of the fibrotically thickened and aged intima, by spreading apart the smooth muscle cells with expanding matrix materials, could be the conditioning factor that brings about the intrusion of atheronecrosis.

Adolescent↗
PubMed1989

[The basilar artery of humans].

The basilar artery in 44.4% of the cases came into being by joint of two vertebral arteries on the height of the inferior margin of the pont. However, in 40.4%--below, and in 15.1%--above of this margin. In 78.7% of the human the course of basilar artery was rectilinear. In 20.5% of the cases the bulge of this artery was observed on the right or left side, whereas in 0.8%--the S-shaped forms. In 56% of the persons the segmentation of the basilar artery on the posterior cerebral arteries takes place on the height of the superior margin of the pont, in 32.9%--above, and in 11.1%--below this one. The results of the investigations concerning the place of genesis, the height of segmentation and the direction of course of the particular artery, were permitted on separation of nine types of these blood vessels. The diameter of the initial and terminal section of the basilar artery at the new-born children was--respectively--1.9 and 1.8 mm, whereas at the adult persons it exceeded 4 mm. The length of this vessel ranged from 17.2 mm in the above-mentioned children to approximately 33 mm in persons over 20 years old. In all the examined cases the basilar artery was passing the arteries of the pont: medial and lateral and almost always the superior and the inferior anterior cerebellar arteries. In 12.4% of the persons the inferior posterior cerebellar arteries and, moreover, in 22.2%--the labyrinth arteries were beginning from this blood vessel.

Adolescent↗
PubMed1996

Effects of angiotensin I and angiotensin II in blood vessels: greater influence of converting enzyme activity in the rabbit basilar artery.

We investigated the constrictor effects of Angiotensin I (Ang I) and Angiotensin II (Ang II) on rabbit peripheral (aorta, carotid artery, mesenteric artery, saphenous artery) and cerebral (basilar artery) vessels and in rat aorta in functional organ bath studies. The effect of angiotensin converting enzyme (ACE) inhibition by captopril was also assessed in these preparations. Ang II elicited concentration-dependent contractions with comparable potency in rabbit and rat endothelium-free vascular rings (pD2 about 8.5) which indicates a lack of species and regional variation in the contractile responses to Ang II. The responses to Ang II were reduced by the presence of a functional endothelium in rabbit mesenteric artery and in rat aorta. Since ACE determines the plasma and tissue conversion of Ang I to active Ang II, we calculated the ratio R (EC50 Ang I-induced contraction: EC50 Ang II-induced contraction) as an indicator of the tissue ACE effectiveness. In the aorta without endothelium, Ang I was found to be much less potent than Ang II in the rabbit (R = 44) compared with the rat (R = 3.5). This species difference in the aortic conversion of Ang I to Ang II was confirmed by the use of captopril. Captopril (10(-6) M) shifted the Ang I concentration/ response curve by 2- and 14-fold to the right in rabbit and rat respectively. In other rabbit blood vessels, the rank order of potency to Ang I in endothelium denuded rings was basilar artery > > carotid artery > or = aorta > or = saphenous artery. In addition, the R value was the lowest for the basilar artery (R = 2.5). This is in agreement with the highest rightward shift (78-fold) of the Ang I concentration/response curve by captopril for basilar artery in comparison with only 3-, 8- and 3-fold shifts observed in carotid artery, saphenous artery and aorta respectively. In conclusion, our data provide evidence for a greater influence of ACE in rabbit basilar artery than in peripheral vessels.

Angiotensin I↗
PubMed2002

Magnetic resonance imaging in basilar artery occlusion.

CONTEXT: Acute basilar artery occlusion has particularly high mortality and morbidity. OBJECTIVE: To determine the potential utility of advanced magnetic resonance imaging (MRI) methods, including diffusion-weighted imaging, for the early management of patients with basilar artery thrombosis. DESIGN: Case series. SETTING: Institute of Neuroradiology and Department of Neurology, Johann Wolfgang Goethe University, Frankfurt, Germany. PATIENTS: In 4 patients with occlusion of the basilar artery, MRI was performed, including T2-weighted and diffusion-weighted imaging (DWI) sequences and magnetic resonance angiography (MRA) in the short-term phase (<12 hours). Three patients underwent intra-arterial thrombolysis. Clinical outcome was obtained 10 days after symptom onset. RESULTS: The MRA was performed 3.5 to 11.5 hours after symptom onset and showed basilar artery occlusion in all cases. The DWI revealed different patterns of ischemic lesions. In 2 patients, no or only small lesions could be identified; the remaining showed multiple and large lesions within the posterior circulation territory. Initial clinical status was severely impaired in all cases (Rankin scale score, 4-5). Thrombolysis was initiated in 3 patients, leading to successful recanalization in 2. Clinical outcome was favorable in the 2 patients with small DWI lesions and successful reperfusion (Rankin scale score, 2), whereas it was worse in those with large DWI lesions and persisting occlusion (death, persisting coma). CONCLUSIONS: In critically ill patients with acute basilar occlusion, the extent of DWI lesion involvement can be highly variable. Small DWI lesions seem to be associated with a favorable outcome if reperfusion is achieved with thrombolysis. This could potentially be the case independent of time from symptom onset.

Aged↗
PubMed2000

Basilar artery occlusion due to mucormycotic emboli, preceded by acute hydrocephalus.

A rare case of brain stem infarction caused by mucormycotic emboli, preceded by acute hydrocephalus, is reported. The patient, who had suffered from leukemia and had undergone bone marrow transplantation several months before, presented initially with seizure and persistent disturbance of consciousness. A head CT scan revealed marked ventricular dilation and diagnosed as acute hydrocephalus. The patient received emergent ventricular drainage. Despite the aggressive treatment, the patient did not survive. Autopsy revealed systemic mucormycosis occluding and invading various arteries including basilar artery and its branches, causing fatal brainstem infarction. Although early diagnosis remains difficult in the cases of systemic mucormycosis, prompt initiation of treatment is mandatory; one must have in mind the possibility of presence of fungal infection when treating patients with acute neurological deterioration who have underlying debilitating diseases, even though fungi themselves are hard to detect in most cases.

Acute Disease↗
PubMedDate not supplied

3DFT MR angiography of carotid and basilar arteries.

Three-dimensional Fourier transform (3DFT) time-of-flight and two-dimensional Fourier transform (2DFT) projection phase-contrast MR angiography was performed in eight healthy volunteers and in 14 patients with known carotid artery or basilar artery occlusion, stenosis, or dissection. Comparative angiography was available in 13 cases (although in some cases the studies were separated by a number of months) and duplex sonography in one case. After localization of the carotid artery bifurcations by using 2DFT projection phase-contrast angiography, multiple 1.25-mm contiguous images were obtained with the 3DFT technique. In all cases, the lesions were identified on MR angiography. Because flow is detected in a manner that is independent of flow-induced phase shifts in the 3DFT time-of-flight technique, signal loss arising from complex flow and turbulence is minimized, yet the flow image remains sensitive to all velocity components of flow. Applications of this technique are ideal for relatively straight vessels where flow is laminar, but it can also be used to evaluate the carotid artery bifurcations where flow becomes complex.

Adult↗
PubMedDate not supplied

Comparison of blood flow and patency in arterial and vein grafts to basilar artery.

Blood flow and patency rates obtained by lingual to basilar artery anastomosis were compared with those obtained by saphenous vein bypass graft from the carotid to the basilar artey in two groups of ten dogs. Flow was measured by an electromagnetic technique while blood pressure and blood gases were monitored. Graft patency also was determined by angiography and histological examination. The arterial and venous grafts carried more than enough blood to maintain a normal flow (9.5 ml per minute) through the basilar system of dogs. Immediately after anastomosis, average flow through the vein grafts was 15.5 ml per minute (range 10 to 24 ml per minute). Six weeks later, average flow through the vein graft was 11.5 ml per minute and through the arterial graft 13 ml per minute. With induced hypertension, flow increased in the arterial grafts to an average of 26.2 ml per minute and in the vein grafts 24 ml per minute. Hypercarbia increased arterial graft flow to an average of 27.8 ml per minute and vein graft flow to 23.5 ml per minute. By angiography, graft patency was shown in only 80% of the grafts at one week and in 60% at six weeks postoperatively, even though all grafts were patent by flow and histological determinations. This failure of angiography represents a limitation of the radiographical resolution in millimeter-sized vessels.

Animals↗
PubMed2001

Distal stump of an occluded intracranial vertebral artery at the vertebrobasilar junction mimicking a basilar artery aneurysm.

The distal stump of an occluded intracranial vertebral artery (VA) can mimic a basilar artery aneurysm of the vertebrobasilar junction. Their differentiation is crucial to establishing the appropriate treatment. We report two cases with occlusion of the distal stump of the VA due to atherosclerosis and arterial dissection. Magnetic resonance images with three-dimensional constructive interference in steady state sequences are useful in revealing the occluded segment as a continuous anatomical structure from the proximal VA to the basilar artery. This information may prevent unnecessary exploratory surgery for a suspected basilar artery aneurysm.

Adult↗
PubMed2004

Long-term outcome after intravenous thrombolysis of basilar artery occlusion.

CONTEXT: Basilar artery occlusion (BAO) is an infrequent disease with high morbidity and mortality. Intra-arterial thrombolysis is advocated for treatment but is limited to use at specialized centers. OBJECTIVE: To evaluate outcomes for patients with BAO treated with intravenous thrombolytic therapy. DESIGN, SETTING, AND PARTICIPANTS: During 1995 to 2003, 50 consecutive patients with angiographically proven BAO were treated according to an institutional therapy protocol based on intravenous thrombolysis with recombinant tissue plasminogen activator (alteplase). Patients were treated at an urban university teaching hospital receiving all patients with ischemic stroke who were considered for thrombolysis in a catchment area of 1.5 million inhabitants in Helsinki, Finland. INTERVENTION: Intravenous administration of alteplase (0.9 mg/kg) during a 1-hour infusion. MAIN OUTCOME MEASURES: Basilar artery recanalization determined by magnetic resonance angiography and clinical outcomes at 3 months and at 1 year or longer determined by modified Rankin Scale and Barthel Index scores. RESULTS: Recanalization was studied in 43 patients and verified in 26 (52%) of all patients. By 3 months, 20 patients (40%) had died while 11 had good outcomes (modified Rankin Scale score, 0-2); 12 (24%) reached independence in activities of daily living (Barthel Index score, 95-100), and 6 (16%) were severely disabled (Barthel Index score, 0-50). In the long term (median follow-up 2.8 years), 15 patients (30%) reached good outcomes (modified Rankin Scale score, 0-2) while 23 (46%) died. CONCLUSIONS: Intravenous administration of alteplase for patients with BAO appears to be associated with rates of survival, recanalization, and independent functional outcome comparable with those reported with endovascular approaches. These data suggest that a randomized trial is needed to compare these approaches for treatment of BAO.

Adult↗