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H C Nahser

Publications and source records attributed to H C Nahser.

At least 19 recordsLinked to original sources
PubMed2004

Cerebral aneurysm associated with an intracranial tumour: staged endovascular and surgical treatment in two cases.

Two cases are reported in which an anterior communicating artery aneurysm was associated with an intracranial tumour. The tumour was a suprasellar meningioma in one case and an optic chiasm/hypothalamic astrocytoma in the other. In both cases, the aneurysm was successfully embolized using Guglielmi detachable coils. Subsequently craniotomy was performed with complete excision of the meningioma and subtotal removal of the astrocytoma. Endovascular techniques can be employed to make the surgical excision of an intracranial tumour co-existing with an incidental aneurysm safer.

Adult↗
PubMed2001

Noninvasive follow-up of GDC-treated saccular aneurysms by MR angiography.

The aim of this study was to determine sensitivity and specificity of magnetic resonance angiography (MRA) for the assessment of durable occlusion of intracranial aneurysms with Guglielmi detachable coils (GDC) and to point out the influence of MRA results in re-intervention strategies. Forty-five patients with 54 aneurysms that were previously treated by endovascular occlusion with GDC were selected for this study. All patients underwent digital subtraction angiography (DSA) and MRA examinations on the same day. The time-of-flight MRA studies were performed on a 1-T scanner. The MRA images were first read by radiologists who were not aware of the DSA results. In a second consensus reading by the neuroradiologists who had performed all interventional procedures of this series, the decision was made as to whether re-treatment was necessary. The distribution of aneurysm sizes, configurations and treatment results were sufficient for an unbiased evaluation. The first blinded evaluation revealed a sensitivity of 71% and a specificity of 95% for MRA assessment of aneurysm reperfusion. In the second consensus reading, the sensitivity increased to 92% and the specificity was 98%. The blinded reading indicates that MRA is a useful adjunct to DSA for the assessment of durable results after endovascular treatment of intracranial aneurysms. In the consensus reading it became obvious that sensitivity and specificity of MRA can be increased to 92 and 98%, respectively, if the results were evaluated by experienced neuroradiologists, including prior knowledge of all other examinations. We have already increased the follow-up intervals for DSA and use MRA intermittently, based on these results.

Adult↗
PubMed2000

Significantly increased prevalence of factor V Leiden in patients with dural arteriovenous fistulas.

Resistance to activated protein C (APCR) is the most common genetic risk factor for venous thrombosis and is generally caused by a mutation in the factor V (FV) gene leading to FV Leiden. The recent finding of FV Leiden in three of seven patients with dural arteriovenous fistulas (DAVFs) prompted us to evaluate systematically the role of APCR due to FV Leiden in the pathogenesis of DAVFs in 22 patients and age- and sex-matched controls. We found a significantly higher frequency of APCR and FV Leiden in the patient group than among controls (5/22 vs. 0/22, P=0.048, Fisher's exact test). We conclude that APCR due to FV Leiden is of pathogenetic significance in a subgroup of DAVFs.

Activated Protein C Resistance↗
PubMed2000

Intracranial vertebrobasilar stenosis: angioplasty and follow-up.

BACKGROUND AND PURPOSE: When medication fails to improve symptoms of atherosclerotic stenosis of the intracranial vertebral and basilar arteries, percutaneous transluminal angioplasty (PTA) is considered. However, because investigators disagree on the usefulness of this procedure, we conducted a retrospective study to evaluate the indications, efficacy, and safety of PTA. METHODS: Twenty patients underwent PTA of the vertebral (n = 14) or basilar (n = 6) artery, 18 for neurologic signs and symptoms of arterial stenosis that recurred or progressed despite pharmacotherapy and two prophylactically. Neurologic examinations were performed before and after the procedure and arterial patency was evaluated at follow-up by digital subtraction angiography and/or MR angiography. Imaging follow-up was available for 14 (70%) of the 20 patients, neurologic follow-up for 15 (75%). RESULTS: The stenosis was successfully dilated in all patients, and on follow-up neuroradiologic examinations, vessel patency could be seen in 12 (86%) of 14 patients. Only one (7%) of 15 patients who returned for a follow-up neurologic examination had new symptoms (caused by occlusion of the vertebral artery 4 months after the procedure). One patient had a reversible neurologic deficit and one had hemiparesis after PTA. No patient died as a result of PTA. CONCLUSION: In our study, PTA of intracranial vertebrobasilar arteries was associated with a low mortality and morbidity rate and with a high degree of patency. This technique may therefore be regarded as an effective means of improving the patency of stenotic arteries. In selective cases, it might be considered for use prophylactically.

Aged↗
PubMed1999

[Pseudoaneurysm of the extracranial internal carotid artery. Treatment by stent and coil implantation].

Pseudoaneurysms of the extracranial internal carotid artery (ICA) can be caused by external injury or may be due to spontaneous dissection. Pseudoaneurysms bear an increased risk of arterio-arterial embolism. Treatment of pseudoaneurysms is influenced by the location and the type of injury, associated injuries, collaterals to the ipsilateral hemisphere, neurological signs and symptoms, growth of the lesion and patient age. Potential treatment regimen include conservative and medical approaches with anticoagulation and antiplatelet therapy, extra-intracranial bypass, resection of the pseudoaneurysm with vessel reconstruction, ligation or endovascular balloon occlusion of the ICA. Pseudoaneurysms of the ICA adjacent to the skull base require a major surgical procedure. If there are contra-indications for vessel occlusion conservative or medical treatment used to be the only therapeutic alternatives. We report the treatment of two patients with extracranial ICA pseudoaneurysms after blunt injury with stent placement (in one case combined with coil embolization) as a further treatment option.

Adult↗
PubMed1998

[Clinical application of transcranial color-coded duplex ultrasound for detection of intracranial aneurysms].

We investigated 88 Patients with a total of 102 angiographically diagnosed intracranial aneurysms by means of transcranial colour coded Duplex sonography (TCCD) during a time period of 15 months. Both the size and the localization of the aneurysms were determined. Seventy aneurysms (77%) with a diameter of 16 +/- 8 mm (6-55 mm) were detectable, with excellent visualization in 36 (42%), moderate visualization in 34 (40%), and no sufficient visualization in 16 (16%) aneurysms, respectively. In another 16 cases (16%) there was no sufficient vone window. Thrombotic material inside the aneurysm was detectable in 16/20 cases (75%), visualization of coil embolized aneurysms in 12/25 patients (48%). TCCD allows the follow up of cerebral aneurysms, with the detection of thrombosis and treatment effects after embolization. The method is not valid for the detection of intracranial aneurysms.

Adolescent↗
PubMed1998

Endovascular therapy of brain AVMs prior to radiosurgery.

The purposes of this study were to determine the safety and efficacy of embolization of brain AVMs prior to radiosurgery and to evaluate the total obliteration rate achieved. The brain AVMs of 64 patients were subselectively embolized mainly with NBCA, platinum microcoils and/or PVA. The aim of embolization was the reduction of the target volume and/or the elimination of vascular structures bearing an increased risk of hemorrhage. Presenting symptoms were intracranial hemorrhage in 33 patients, a seizure disorder in 21 patients, and headache in 6 patients. Four AVMs had been detected as an incidental finding. The initial AVM volume was in the range of 0.5 to 84 cc (mean 17 cc). Grading of the AVMs according to the Spetzler-Martin scale showed the following distribution: grade I, 3x; II, 13x; III, 11x; IV, 17x; V, 4x; VI, 16x. A total of 300 endovascular procedures including 47 subselective catheterizations without and 253 with embolization were performed. A size reduction of the AVMs between 10% and 95% (mean 63%, median 70%) was achieved. Neurological symptoms due to treatment complications were transient in 12 patients, of minor clinical significance but permanent in 4 patients. Following radiosurgery, one patient died due to recurrent intracerebral hemorrhage. Three patients are doing well but refused final follow-up angiography. A total of 30 patients is currently within the latency interval after radiosurgery. Radiosurgery failed to obliterate the embolized AVMs in 16 patients. Angiography confirmed complete nidus obliteration in 14 patients. The endovascular treatment of brain AVMs prior to radiosurgery proved safe and effective and may be considered in either high grade or incidental AVMs. AVM obliteration after embolization and radiosurgery is less frequently achieved than after stereotactic irradiation of primarily small AVMs.

Adolescent↗
PubMed1998

Detection of microemboli distal to cerebral aneurysms before and after therapeutic embolization.

PURPOSE: Recently developed interventional radiologic techniques, such as embolization with platinum coils, may induce thrombus formation within an aneurysm. The aim of the present study was to investigate the frequency of microemboli distal to untreated and treated cerebral aneurysms. METHODS: Among a total of 110 patients treated with platinum coil embolization, 35 patients (27 women and eight men, aged 50+/-10 years) who were at high risk of ischemic complications underwent emboli detection with a transcranial Doppler sonographic monitoring system. All patients were studied before and after coil embolization. The aneurysms were located at the internal carotid artery (n=14), the basilar artery (n=10), the middle cerebral artery (n=7), or the vertebral artery (n=4). Twenty-nine (85%) of 35 patients were monitored within 6 hours of the completion of treatment. RESULTS: Microemboli distal to the aneurysm were not detected in any of the patients before treatment. Microemboli were detected in 11 patients (31%) after embolization (mean, 16+/-21 per hour; range, 1-74 per hour). Microemboli were detected in five (71%) of seven patients in whom ischemic complications occurred after treatment, but in only six (21%) of 28 asymptomatic patients. This difference was statistically significant. The rate of occurrence of emboli in patients with ischemic complications (23+/-30 emboli per hour) was higher than in asymptomatic patients (10+/-7 emboli per hour), but this difference was not statistically significant. CONCLUSION: Microemboli were detected significantly more often in patients who suffered from cerebral ischemia after coil embolization of an intracranial aneurysm. This observation supports the definition of a high-risk group of patients with incomplete embolization or with a large-diameter, broad-neck aneurysm. The early detection of microemboli after treatment may be an indicator for excessive intraaneurysmal thrombus formation and could influence the decision for prophylactic treatment with heparin or aspirin.

Aneurysm↗
PubMed1996

Lymphocytic encephalomyeloneuritis as a neurologic complication of ulcerative colitis.

Ulcerative colitis (UC) is a chronic relapsing inflammatory bowel disease (IBD) showing immunologic abnormalities and association with autoimmune states (Snook et al., 1989). Extraintestinal manifestation of UC affect various organ systems (Podolsky, 1991). We describe morphologically documented encephalomyeloneuritis in a 58-year-old white male with UC in full remission providing support for the concept that ulcerative colitis may be complicated by neurologic manifestations affecting both the central and peripheral nervous system.

Colitis, Ulcerative↗
PubMed1996

Visualisation of intracranial aneurysms by transcranial duplex sonography.

We examined 72 patients with 89 angiographically confirmed intracranial aneurysms, using transcranial colour-coded duplex sonography (TCCD) to determine the location and size of the aneurysm. The patients were admitted for coil embolisation of their aneurysm following subarachnoid haemorrhage or because of a cranial nerve palsy. Using a 2/2.25 MHz transducer, 42 aneurysms (47%) were seen satisfactorily through the temporal bone window or foramen magnum. In 24 cases (27%) image quality was insufficient as a result of a poor bone window, of the aneurysm having a diameter of less than 6 mm or of its being in an unfavorable location. In 23 other cases (26%) it was not possible to detect the aneurysm. Thrombosed structures could be demonstrated using TCCD in 8 of 12 giant intracavernous or basilar artery aneurysms, and in 15 of 19 aneurysms treated by platinum coil embolisation. TCCD offers a noninvasive method for monitoring progressive intra-aneurysmal thrombosis following coil embolisation and for follow-up of patients with untreatable fusiform aneurysms, should this be required. Detection of small aneurysms is limited by spatial resolution and insonation angles.

Aneurysm, Ruptured↗
PubMed1995

Transcranial color-coded duplex sonography in cerebral arteriovenous malformations.

BACKGROUND AND PURPOSE: It is well known that significant changes in cerebral hemodynamics may occur during the treatment of cerebral arteriovenous malformations with the complication of intracerebral hemorrhage and parenchymal edema. We used transcranial color-coded duplex sonography to study alterations in blood flow velocities during staged embolization. METHODS: Forty-one patients aged 40 +/- 13 years (mean +/- SD) with angiographically proven cerebral arteriovenous malformations were studied. The blood flow velocities of the anterior, middle, and posterior cerebral arteries were measured in 16 patients with supratentorial arteriovenous malformations, both before the first and then after each successive embolization (three to seven treatments). RESULTS: In 29 of 41 patients (71%), transcranial color-coded duplex sonography satisfactorily revealed the malformations and their main feeders. After the final embolization, we found a reduction in the peak flow velocity in treated feeders of 23 +/- 28% compared with the values before the first embolization. The untreated feeders showed an increase in peak flow velocities of 12 +/- 23% as an expression of increased collateral flow. After the treatment of the supplying feeders, we observed a reduction in flow velocity of 25 +/- 13% in seven patients, with cross-filling of the arteriovenous malformation through the contralateral anterior cerebral artery and the anterior communicating artery. CONCLUSIONS: The technical advantage of transcranial color-coded duplex sonography compared with transcranial Doppler sonography is that it allows the exact identification of different feeding arteries in arteriovenous malformations. Repeated measurements during stepwise embolization with corrected insonation angle are easily achieved, and noninvasive quantification of hemodynamic changes is possible. The method may be helpful in the planning of the different steps of embolization.

Adult↗
PubMed1995

[Therapy of cerebral aneurysms and arteriovenous vascular malformations in hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber disease)].

Little is known about the course of cerebral aneurysms in hereditary hemorrhagic teleangiectasia (Rendu-Osler-Weber's disease). Thus, therapeutic decisions are often difficult. For the first time, we report the successful embolization of an arteriovenous fistula and multiple aneurysms of the posterior inferior cerebellar artery (PICA) of a patient with Rendu-Osler-Weber's disease after subarachnoid hemorrhage. Two years later she suffered another severe intracranial hemorrhage. Angiography revealed an aneurysm in the same artery (PICA), which spontaneously disappeared within 2 months. Spontaneous regression of aneurysms in Rendu-Osler-Weber's disease has not been reported before.

Cerebellum↗
PubMed1994

Blood flow velocity and vasomotor reactivity in patients with arteriovenous malformations. A transcranial Doppler study.

BACKGROUND AND PURPOSE: A large percentage of patients with a cerebral arteriovenous malformation (AVM) show focal neurological signs or have a history of intracranial hemorrhage. The present study used transcranial Doppler sonography to assess the clinical significance of hemodynamic disturbances in the intracranial arteries of patients with an AVM. METHODS: Eighteen patients with untreated AVMs were examined clinically, angiographically, and with transcranial Doppler sonography (blood flow velocity measurement and vasomotor reactivity in all main intracranial arteries). RESULTS: A pathological increase in blood flow velocity (57.6%) and a decrease in vasomotor reactivity (72.7%) were frequently found in AVM feeding arteries. Vasomotor reactivity was also reduced in several nonfeeding arteries both ipsilateral (53.3%) and contralateral (30.8%) to the AVM. AVM size was a poor predictor of pathological transcranial Doppler results. Vasomotor reactivity of arteries ipsilateral to an AVM in patients with a history of hemorrhage was significantly higher (2.10 +/- 1.66% per mm Hg; mean +/- SD) than in patients with no history of bleeding (1.12 +/- 1.48% per mm Hg; P < .05). In patients with focal neurological signs but no history of hemorrhage, the percentage of arteries ipsilateral (100%) and contralateral (63.6%) to an AVM showing a pathological vasomotor reactivity was significantly larger than in nonhemorrhagic patients without focal signs (66.7% and 22.2%, respectively; both P < .05). CONCLUSIONS: Our results suggest two distinct relations between transcranial Doppler results and clinical findings: (1) Relatively normal vasomotor reactivity values in arteries ipsilateral to an AVM indicate a high-pressure AVM with an increased risk of hemorrhage. (2) A strongly pathological vasomotor reactivity in arteries ipsilateral and contralateral to an AVM indicates a low-pressure AVM with a higher prevalence of hemodynamically induced neurological signs.

Adolescent↗
PubMed1994

[Cerebral arteriovenous malformations. Diagnosis, clinical aspects and therapy].

An overview of cerebral arteriovenous malformations is presented. These congenital lesions are classified according to volume, number of feeding arteries, type of venous drainage, and localization. Clinical manifestations are intracerebral or subarachnoidal hemorrhages, or symptomatic epileptic seizures. Most patients with AVM exhibit their first symptoms before the age of 40. Migraine-like headaches and "steal" phenomena are rarely the main symptoms. Diagnosis is obtained by means of MRI and selective angiography; the treatment of choice is a combination of interventional neuroradiological therapy, radiosurgery and/or microsurgery which is adjusted to the individual case.

Cerebral Hemorrhage↗
PubMed1993

[Endovascular Doppler sonography of intracranial blood vessels. Technical indications and potential applications].

Intravascular Doppler ultrasonography was initially performed with specially designed catheters and was used primarily for cardiological purposes. The recent introduction of a 0.018-in. flexible, steerable guide wire with an integrated 12-MHz piezoelectric transducer (FloWire) has made it possible to use this technique in neuroangiography. This system allows recording of Doppler spectra and determination of blood flow velocities in intracranial vessels after subselective introduction of a standard 3-F microcatheter. The measurement of blood flow velocity in an AVM feeding branch of a middle cerebral artery and the haemodynamic effects of the vasoconstrictive substance sumatriptan on the middle meningeal artery are used to illustrate potential applications of intravascular Doppler ultrasonography in neuroangiography.

Adult↗
PubMed1992

Local thrombolytic therapy for thromboembolic occlusion of the middle cerebral artery.

We report on 10 patients with thromboembolic occlusion of the middle cerebral artery (MCA) who underwent local thrombolytic therapy. Six patients developed a MCA occlusion during long-standing interventional neuroradiological procedures, while four had a proven or suspected cardio-embolic stroke. Streptokinase or urokinase was applied by a microcatheter placed into the thrombus within six hours of clinical onset. Complete or partial revascularization was achieved in all patients. Recovery was complete in seven and partial in three of the patients. In two patients, minor haemorrhagic transformation of the infarct occurred, which did not lead to neurological deterioration. It is concluded that in a selected group of patients with MCA occlusion, local thrombolytic therapy represents a safe and effective therapy.

Adult↗