[Availability of mechanical thrombectomy for acute stroke : Analysis of the health care reality in Germany]. / Verfügbarkeit der mechanischen Thrombektomie bei akutem Hirninfarkt : Analyse der Versorgungsrealität in Deutschland.

BACKGROUND: Mechanical thrombectomy (MT) has become an evidence-based therapy for stroke patients with proximal vessel occlusion of the anterior cerebral circulation. Nationwide availability of MT for all eligible patients within the shortest possible time window is a major challenge. AIM OF THE STUDY: Nationwide analysis of the rates of systemic thrombolysis (STL) and MT in Germany according to region and hospital-based evaluation. METHODS: The evaluation involved data analysis of the diagnosis-related groups (DRG) statistics and structured quality reports of hospitals for 2010 and 2014. The rates and changes of STL and MT were evaluated in the 413 German districts with reference to the corresponding case number of patients with acute ischemic stroke. RESULTS: Nationwide recanalization treatment rates increased from 2010 to 2014 both for STL (from 8.0% to 11.6%) and MT (from 0.7% to 2.3%). High variations were observed depending on the patient's place of residence (STL = 3.4-36.7%, MT = 0-7.4%). In 2014 a total of 5526 MT were coded in a total of 244,757 ischemic strokes. A total of 134 hospitals with more than 2 MT per year were identified; however, 21% of the nationwide MTs were performed in only 7 hospitals with more than 100 MT/year. In 308 (75%) of the 413 districts, not a single MT was performed. CONCLUSION: Due to a narrow net of certified stroke units with nationwide availability of STL, excellent structural conditions for treatment of acute stroke patients are already established in Germany. With regard to the nationwide availability of MT, there is still a need for optimization. Despite the increasing number of hospitals providing MT as an emergency procedure, a trend toward large intervention centers with supraregional catchment areas can be observed.

Superselective microcoil embolization in severe intractable epistaxis: an analysis of 12 consecutive cases from an otorhinolaryngologic and an interventional neuroradiologic point of view.

From 2006 to 2013, 12 patients with severe epistaxis refractory to prior conservative and surgical therapy were treated by superselective embolization of nasal arteries. Supersoft platinum microcoils with smallest diameters were used as the sole embolic agent in all cases. Coils were applied far distally in a stretched position for obtaining ideal target vessel superselectivity. The objective of this study is to evaluate efficacy and complications of superselective coil embolization for treatment of severe intractable epistaxis and to discuss results from an otorhinolaryngologic and an interventional neuroradiologic point of view. Retrospectively, all epistaxis inpatients between 2006 and 2013 were identified and subdivided by form of treatment: conservative, surgical and interventional therapy. Medical records of interventionally treated patients were reviewed for demographics, medical history, risk factors, clinical data, complications and short-term success, and patients were followed up for long-term success. Mean follow-up was 37 months. In 12 patients, 14 embolizations were carried out, with short-term success in 9 patients (75%), while early post-interventional rebleeding occurred in 3 patients (25%). Of 9 patients with short-term success, 1 died during stay, 1 was lost to follow-up and 1 had minor re-bleeding after 30 months. Six patients had short-term and long-term success. Before the first embolization, 3 ± 1 conservative and/or surgical procedures had been undertaken. Length of stay was 12.8 ± 3.6 days. 8 patients (67%) received red cell concentrates. Most frequent complications were mucosal damage and nasal pain, but these were related to repeated packing and surgery. Typical embolic complications as neurological or visual impairment or soft tissue necrosis were not observed in any patient. From the otorhinolaryngologic point of view, surgery is the treatment of choice in severe refractory epistaxis, but in case of repeated failure, superselective microcoil embolization is a valuable addition to the therapeutic spectrum. From the interventional neuroradiologic point of view, superselective microcoil embolization is an effective, well tolerable and safe procedure and complications may be reduced in comparison to microparticle embolization. Modern supersoft microcoils with smallest diameters enable ideal superselectivity of the target vessels.

Doppler Ultrasound Flow Reversal in the Superior Sagittal Sinus to Detect Cerebral Venous Congestion in Vein of Galen Malformation.

BACKGROUND AND PURPOSE: Vein of Galen malformation is a rare congenital cerebrovascular malformation. In affected patients, increased cerebral venous pressure constitutes an important etiologic factor for the development of brain parenchymal damage. The aim of this study was to investigate the potential of serial cerebral venous Doppler measurements to detect and monitor increased cerebral venous pressure. MATERIALS AND METHODS: This was a retrospective monocentric analysis of ultrasound examinations within the first 9 months of life in patients with vein of Galen malformation admitted at <28 days of life. Categorization of perfusion waveforms in the superficial cerebral sinus and veins into 6 patterns was based on antero- and retrograde flow components. We performed an analysis of flow profiles across time and correlation with disease severity, clinical interventions, and congestion damage on cerebral MR imaging. RESULTS: The study included 44 Doppler ultrasound examinations of the superior sagittal sinus and 36 examinations of the cortical veins from 7 patients. Doppler flow profiles before interventional therapy correlated with disease severity determined by the Bicêtre Neonatal Evaluation Score (Spearman ρ = -0.97, P = < .001). At this time, 4 of 7 patients (57.1%) showed a retrograde flow component in the superior sagittal sinus, whereas after embolization, none of the 6 treated patients presented with a retrograde flow component. Only patients with a high retrograde flow component (equal or more than one-third retrograde flow, n = 2) showed severe venous congestion damage on cerebral MR imaging. CONCLUSIONS: Flow profiles in the superficial cerebral sinus and veins appear to be a useful tool to noninvasively detect and monitor cerebral venous congestion in vein of Galen malformation.

[Vascular interventions in the head and neck region. Part 1: Recanalization procedures]. / Vaskuläre Interventionen im Kopf-Hals-Bereich. Teil 1: Rekanalisierende Verfahren.

Vascular interventions in the head and neck region are becoming increasingly more important due to acquisition of knowledge on the pathophysiological principles of various vascular diseases and the development of new intervention materials. This article gives a review of the materials and techniques used in interventions in the head and neck region. Special attention is given to the description of a safety-oriented approach to avoid potentially severe complications. Based on this the value of endovascular therapeutic procedures for recanalization of various diseases will be discussed, in particular the treatment of extracranial and intracranial stenoses and the reopening of vascular occlusions in acute stroke using PTA, stents, lysis and mechanical thrombus removal.

[Vascular interventions in the head and neck region. part 2: procedures for vessel occlusion]. / Vaskuläre Interventionen im Kopf-Hals-Bereich. Teil 2: Gefäßverschließende Verfahren.

As a result of continuing progress in the development of intervention materials but also due to growing understanding of pathophysiological relationships, the prevalence and significance of endovascular interventions in the head and neck region have continued to increase. This applies to procedures for recanalization, which were addressed in detail in an earlier article, as well as to techniques used for vessel occlusion. This contribution first presents the techniques and materials employed in embolization in the head and neck region. Based on this description the application of endovascular procedures for vessel occlusion are explained with respect to different disease entities in the head and neck region. In this context particular attention is given to the treatment of intracranial aneurysms, cerebral arteriovenous malformations, dural AV fistulae, vascular malformations, and tumors in the head and neck region.

[Modern cross-sectional imaging of head and neck vessels]. / Moderne Schnittbildgebung der Kopf-Hals-Gefässe.

Although digital subtraction angiography (DAS) remains the gold standard for neurovascular imaging, the number of diagnoses made on the basis of less invasive cross-sectional imaging techniques (CT and MR angiography) is increasing. The present article provides important technical principles of CT and MR angiography, followed by an analysis of the diagnostic possibilities and limitations of vascular cross-sectional imaging. The particular importance of post-processing of vascular cross-sectional datasets is also discussed. Using the typical clinical diagnostic work-up of extra- and intracranial vascular diseases as a basis, the article explains how a suitable examination technique and protocol is chosen and which limitations need to be borne in mind. After taking at look at the technical advances expected in the future (3-Tesla MRA, dual-energy CTA, post-processing workflow in PACS), the remaining indications for diagnostic DSA will be presented and explained.

Evolution of Embolic Agents in Interventional Neuroradiology.

The growth in understanding of the pathophysiological relationships between various neurovascular diseases in the past decades has increased the significance and need for endovascular treatment. Consequently, an extraordinary development of different embolic agents was indispensable. The present work first presents the historical milestones in the discovery of various embolic materials used for neurovascular interventions. In the second part, the current endovascular embolization procedures, requiring both liquid and solid embolic agents, are discussed. In some cases and diseases the combination of both may be mandatory. Special emphasis is placed on the consideration needed when choosing appropriate embolic materials, chiefly depending on the goal of the endovascular procedure. Furthermore, the present understanding of the specifics in angioarchitecture and hemodynamics, leading to the most suitable form of access to the vascular lesion, will be covered. Regarding the latter, it is important to note that the aim should always be to achieve optimal superselectivity while being aware of all approaches, ranging from transarterial and transvenous to direct puncture. Finally, based on the limitations of the currently available embolic materials, we present a brief outlook on the future of new liquid and solid embolic agents.

Technetium-99m HM-PAO brain SPECT in epileptic patients before and during unilateral hemispheric anesthesia (Wada test): report of three cases.

The lipophilic brain SPECT agent [99mTc]hexamethyl propylene amine oxime (HM-PAO) was used in three cases before and during unilateral anesthesia of one hemisphere for lateralization of speech dominance (Wada test). This procedure led to a decrease of regional cerebral blood flow (rCBF) in each of the hemispheres to 55 and 90%, respectively. Diminution of rCBF was significantly more pronounced in the dominant hemisphere. A second phenomenon observed during the Wada test was crossed cerebellar diaschisis. These findings support the assumption that HM-PAO allows monitoring of brain perfusion, as rapid changes of rCBF due to decreased neuronal activity cause respective alterations of cerebral and cerebellar uptake of this new brain agent.

The role of spinal angiography in operations on the thoracic aorta: myth or reality?

BACKGROUND: The importance of preserving the artery of Adamkiewicz during replacement of the thoracoabdominal aorta is debated. We report our experience with the use of preoperative spinal angiography and modification of the surgical technique. METHODS: Between September 1993 and March 1996, 46 patients (mean age, 57 years; range, 25 to 73 years) underwent spinal angiography at our institution, 23 for an aneurysm and 23 for chronic dissection. Localization of the artery of Adamkiewicz between T-9 and L-3 was successful in 30 (65%) patients: T-9, left = 2, right = 1; T-10, left = 4; T-11, left = 10, right = 2; T-12, left = 3, right = 1; L-1, left = 1, right = 2; L-2, left = 2, right = 1; and L-3, left = 1. Thirty-one patients subsequently underwent replacement of the descending thoracic aorta and 13 underwent replacement of the thoracoabdominal aorta. Left atrial-femoral artery bypass was used in 23 patients and full extracorporeal circulation was used in 20 patients. Twelve procedures included the reimplantation of crucial intercostal/lumbar branches. RESULTS: The operative mortality rate was 6.8% (3 of 44 patients) and 1 (2.27%) patient had paraparesis. In addition to the 12 patients who underwent targeted reimplantation of the intercostal branches, evaluation of the spinal cord blood supply influenced the operative technique in 19 other patients. CONCLUSIONS: Selective angiography can demonstrate the spinal cord blood supply even in patients with complex aortic pathology. It is a helpful tool for planning extensive replacement of the thoracic and thoracoabdominal aorta.

Breakdown of the meningeal barrier surrounding the intraorbital optic nerve after experimental subarachnoid hemorrhage.

PURPOSE: The intraorbital optic nerve sheath meninges contain a perineural subarachnoid space lined by meningeal cell layers and intercellular fibrous tissue. We sought to determine whether functional or structural characteristics, or both, of the optic nerve sheath are influenced by the increased intracranial pressure after the rupture of cerebral aneurysms. METHODS: We infused the great cisterns of cats with either x-ray contrast medium or autologous blood. The cisternal infusions were done under the experimental condition of a sudden 2.5-minute increase in intracranial pressure similar to that recorded after the rupture of cerebral aneurysms in humans. RESULTS: Digital subtraction radiographs of the optic nerves taken during the cisternal infusion of contrast medium at the start showed the opacification of the optic nerve subarachnoid space. After 2 minutes, the contrast medium leaked into the orbit, indicating the breakdown of the meningeal fluid barrier. Ultrastructural investigation of the optic nerve sheath after high-pressure cisternal infusions showed the arachnoid cell layers scattered. The flattened arachnoid cells displayed mainly intracellular and some intercellular, porelike openings. After infusion of blood into the great cistern, erythrocytes were found within porelike openings of the arachnoid cells. CONCLUSIONS: The meningeal fluid barrier of the optic nerve sheath can be destroyed by pressure changes associated with subarachnoid hemorrhage. This disruption might be regarded as a natural optic nerve sheath fenestration that allows outflow of cerebrospinal fluid into the orbit to protect the optic nerve from increased intracranial pressure after aneurysmal rupture.

Effect of flunarizine on cerebral blood flow in baboons with or without focal cerebral ischaemia.

In baboons with or without regional cerebral ischaemia (achieved by transorbital clip of the middle cerebral artery), cerebral blood flow (CBF) was measured using the intra-arterial Xenon-133 technique during steady-state, slight hypotension, and hypocapnia before and after administration of various doses of the calcium antagonist flunarizine (0.5 mg kg-1, 1.0 mg kg-1, or 10 micrograms kg-1 min-1 over 30 min). In normal baboons flunarizine did not alter CBF significantly, but at reduced blood pressure it increased CBF by 19.9% owing to exaggerated vasodilatory autoregulation. During hypocapnia flunarizine impaired the physiological reduction in CBF owing to reduced vasoconstriction. In baboons with cerebral ischaemia, CBF measurements were stable and comparable with those in a control group using an arterial clip unless flunarizine was added. In a group of five flunarizine-treated animals, mean CBF after positioning of the clip was higher than in the control group. However, the increase in mean CBF varied significantly between animals, indicating that a secondary reduction in CBF due to postischaemic pathophysiological processes was not prevented consistently.

Transcranial power mode Doppler duplex sonography of intracranial aneurysms.

The application of different color-coding techniques in transcranial color-coded duplex sonography (TCCD) was assessed for detection and measurement of the size of intracranial aneurysms. Thirty-two consecutively examined patients with 36 angiographically verified cerebral aneurysms underwent TCCD with color Doppler flow imaging (CDFI), power Doppler imaging (PDI), and both methods with contrast enhancement. The diameters of the aneurysms were measured in comparable planes by means of angiography and TCCD-PD with and without 400 mg/ml of the monosaccharide microparticle contrast agent Levovist. TCCD with CFD enabled detection of 27 of 36 aneurysms (75%), and PD depicted 29 aneurysms (80%). After administration of Levovist, an additional two aneurysms were detected with CFD and three with PD color coding. Measurements of aneurysm size obtained by means of PD with contrast enhancement corresponded more highly with angiographic findings than did measurements obtained with PD alone. Use of alternative color-coding techniques with the addition of contrast agents increases the number of intracranial nonthrombosed aneurysms detectable with TCCD.

[Possibilities and limitations of CT angiography in comparison to DSA in intracranial aneurysm]. / Möglichkeiten und Grenzen der CT-Angiographie im Vergleich zur DSA bei intrakraniellen Aneurysmen.

PURPOSE: The purpose of this study was to determine the value of CT angiography in the detection of intracranial aneurysms and to discuss its qualities compared with DSA. METHODS: 26 patients with subarachnoid bleeding confirmed by unenhanced CT or lumbar puncture were examined with CT angiography. In 23 of these patients results of DSA were available. RESULTS: In 21 cases 30 aneurysms were found with DSA, whereas in two cases there were no aneurysms. The size of the aneurysms was between 3 and 36 mm. With CT angiography two small 3 mm aneurysms were not detected. In three patients with vasospasms the diagnosis was primarily confirmed by CT angiography. The sizes measured by CTA and DSA were approximately the same. CONCLUSION: Because of the limited spatial resolution small aneurysms (< 5 mm) could not be diagnosed in CTA. Definitive exclusion of aneurysms is therefore not possible. Aneurysms larger than 5 mm are reliably diagnosed. CTA is indicated if identification of the bleeding aneurysm is sufficient for further patient management.

[Phantom studies using echo contrast media to improve the Doppler color sonographic imaging of the superficial femoral artery in the adductor canal]. / Phantomuntersuchungen mit echokontrastgebenden Substanzen zur Verbesserung der farb-doppler-sonographischen Darstellung der A. femoralis superficialis im Adduktorenkanal.

The adductor canal was simulated using 2.6 cm muscular tissue and 2 fasciae to analyse the limits of colour-coded Doppler sonography (angiodynography) in this region. Defects in the spectral signal cause a significant underestimation of mean, peak systolic and peak diastolic (backflow) velocities and of calculated blood flow. Furthermore the pulsatility index is overestimated and the colour-coded visualisation of the arteries is almost lost. For the most part, these changes can be compensated by administration of a sonographic contrast agent (SH U 454). A minimum of 9 mg microbubbles/ml blood is required. Nevertheless, the adjustment of system controls (e.g. transducer power) becomes more difficult and an ideal setting impossible.

[MR tomography, CT and angiography of vascular malformations of the central nervous system]. / MR-Tomographie, CT und Angiographie vaskulärer Malformationen des zentralen Nervensystems.

The findings on MR tomography in 31 vascular malformations of the central nervous system are described; 26 of these had angiography and 24 were examined by CT. There were 19 A-V angiomas, 7 cavernomas and 5 large aneurysms. MRT provided a correct diagnosis in 29 out of 31 cases, angiography succeeded in 19 out of 26 cases and CT in 20 of 24. MRT was superior to CT and angiography. Nevertheless, it cannot replace arteriography, since this is the only method for demonstrating the vascular supply of angiomas and small aneurysms can be demonstrated only by arteriography.

[Phantom studies of the value of color-coded Doppler sonography in arterial occlusive disease of the lower extremities]. / Phantomuntersuchungen zur Wertigkeit der farbkodierten Doppler-Sonographie bei der arteriellen Verschlusskrankheit der unteren Extremitäten.

A new practically orientated phantom for evaluating Doppler Duplex equipment was developed and used to determine the possibilities and limits of color coded Doppler Sonography (Angiodynography) in the diagnosis of arterial occlusive disease of the lower extremity. The problems that may occur in quantifying flow in these arteries are analyzed. The influence of superimposed slices of various soft-tissues on flow quantification, on the spectral waves and on color coded visualisation of the arteries and the possibility to compensate those changes by the use of sonographic contrast agents are discussed.

Treatment of middle cerebral artery occlusion and internal carotid artery dissection with combined mechanical thrombectomy and stenting of the internal carotid artery. A case report.

We describe a case of combined mechanical thrombectomy of the right middle cerebral artery and stent angioplasty of the right internal carotid artery in a severe stroke caused by arterio-arterial embolism due to a traumatic dissection of the internal carotid artery. The patient was admitted with an NIHSS score of 19 and was discharged from hospital with a score of 2. Three months later neurological examination disclosed no pathological findings. The case demonstrates the crucial role of interventional procedures in the treatment of severe stroke where intravenous thrombolysis has little prospect of success.

Origin and course of the extracranial vertebral artery: CTA findings and embryologic considerations.

PURPOSE: The aim of this study was to show the different origins and courses of the extracranial VA on CTA with special emphasis on embryological considerations. The duplicated VA is an anomaly that has been assumed to predispose for dissection and to be associated with aneurysms. We report its frequency and clinical significance. METHODS: We retrospectively reviewed CTA of 539 patients by using a contrast-enhanced CTA protocol of the VA on CT. RESULTS: Ninety-four-point-two percent of left VA originated from left subclavian artery and entered the transverse foramen at C6 in nearly all cases. Six-point-three-percent of left VA (m = 4 %, f = 10 %) originated from the aortic arch and entered the transverse foramen either at C4, C5 or C7 but never at C6. One case of an aberrant retroesophageal right VA originated from the aortic arch distal to the left subclavian artery and entered at C7 (0.19 %). All other right VA originated from the right subclavian artery (99.8 %) and entered between C4 and C6. We diagnosed four cases of duplicated VA (0.74 %) with a female predominance (1.9 %) without any signs of dissection on CTA. Two cases with VA duplication had intracranial arterial aneurysms. CONCLUSIONS: The VA is a longitudinal anastomosis of segmental metameric arteries. The level of entrance into the transverse foramen indicates which metameric artery or arteries persist. Duplication corresponds to persistence of two segmental arteries and is a rare phenomenon. VA duplication might be associated with vascular lesions.

[Possibilities and limits of local intra-arterial fibrinolysis in thromboembolic vascular occlusions of the central nervous system]. / Möglichkeiten und Grenzen der lokalen intraateriellen Fibrinolyse (LIF) bei thromboembolischen Gefässverschlüssen im ZNS.

It is now possible with the help of microcatheters to superselectivity catheterize the cerebral vessels right up to the point of thromboembolic vascular occlusion. Short acting fibrinolytic agents such as urokinase and rt-PA are ideally suited for local intraarterial fibrinolysis (LIF) of thromboembolism in cerebral arteries. Despite high dosages (1,000,000-2,000,000 I.U. urokinase/hr), the risk of symptomatic haemorrhage is relatively low if therapy is started within 4-5 hours of the onset of symptoms and is administered only for a short time (1-2 hrs). To reduce the high mortality rate in patients with thromboembolic occlusion in the vertebrobasilar territory, LIF is the treatment of choice. If therapy is promptly started within 4-5 hours of the clinical onset of symptoms, a favourable clinical course may result even in patients with internal carotid artery or middle cerebral artery occlusions. However, further studies are required to optimize the treatment strategy in the latter group of patients. Results of studies to date have shown that the immediate intraarterial fibrinolysis of the acutely occluded central retinal artery is by far superior to conservative therapy.