Renal ablation in patients with end-stage renal disease.

BACKGROUND: Transarterial catheter embolization of the kidneys (TAE) is a minimally invasive, image-guided procedure. In this study outcome and TAE-related complications of the patients who underwent TAE of the kidneys were evaluated retrospectively. PATIENTS AND METHODS: Between August 2003 and August 2009, 11 patients underwent selective percutaneous transarterial renal embolization for end stage renal disease associated with uncontrolled hypertension, nephrotic syndrome, bleeding or malignancy. TAE of renal arteries was performed using different embolization agents. RESULTS: Successful renal embolization was possible in all 21 kidneys. All patients became anuric. Non-target embolization was not detectable. Nevertheless, all patients developed some degree of postembolization symptoms including nausea, vomiting, fever or pain. A typical finding after embolization was an increase in the C-reactive protein. CONCLUSIONS: Renal embolization is rarely done but should be considered as an alternative to surgical nephrectomy in patients with end stage renal disease due to the lesser invasiveness. Our study confirms the safety and effectivity of percutaneous renal embolization in patients with ESRD. We were able to control the hypertension, nephrotic syndrome, and bleeding caused by ESRD.

Transarterial catheter embolization of a sarcoma for preoperative conditioning.

This paper presents a case of an undifferentiated pleomorphic sarcoma/NOS (not otherwise specified; former pleomorphic - storiform malignant fibrous histiocytoma) of the lower leg, of a huge tumor causing ulceration of the cutaneous surface. To improve preoperative conditions, selective transarterial devascularization of the tumor feeders was performed. At operation the tumor was completely ischaemic allowing for clear tumor demarcation with little blood loss during surgery.

Ischemic and hemorrhagic complications after intra-arterial fibrinolysis in vertebrobasilar occlusion.

BACKGROUND AND PURPOSE: To evaluate the incidence and location of hemorrhagic and ischemic lesions after local intra-arterial (IA) fibrinolysis in patients with acute vertebrobasilar occlusion (VBO). METHODS: One hundred forty-three patients with VBO treated with local IA fibrinolysis were retrospectively evaluated. Two different thrombolytic substances, namely urokinase (UK, n = 57 patients) and recombinant tissue plasminogen activator (rtPA, n = 86 patients), were used. Incidence and location of intracranial hemorrhage and ischemic infarction were assessed by means of 403 peri-interventional CT and MR imaging scans. Recanalization success and bleeding rate were correlated with the type and dosage of fibrinolytic agent. Multiple logistic regression was used for statistical analysis. RESULTS: Intracranial hemorrhage was detected in 46 (32%) patients. Bleeding rate was significantly higher for high-dose rtPA than for UK (36% versus 21%, P < .01). Neurologic outcome was worse in patients with postinterventional bleeding (P < .001). Ischemic infarctions were present in 136 (95%) patients. Ischemic lesions of the occipital lobe and thalamus were more frequently seen in the case of successful recanalization than after absent recanalization (P < .005). Occlusion of the postcommunicating segment of the posterior cerebral artery after successful recanalization was seen in 39% of patients. CONCLUSIONS: In acute VBO, bleeding rate after IA rtPA seems to be higher than that using IA UK, especially after high-dose rtPA. Ischemic lesion patterns after successful local IA fibrinolysis are common and correspond to the frequent distal migration of the thrombus. Novel recanalization techniques allowing for endovascular thrombectomy are needed to reduce ischemic and hemorrhagic complications in the treatment of acute VBO.

Outcome of acute vertebrobasilar occlusions treated with intra-arterial fibrinolysis in 180 patients.

BACKGROUND AND PURPOSE: To evaluate predictors of recanalization and a favorable neurologic outcome in patients with acute vertebrobasilar occlusion (VBO) treated with local intra-arterial fibrinolysis (LIF). METHODS: The multicentric data of 180 patients with acute VBO treated with LIF were retrospectively evaluated. The modified Rankin scale (mRS) was used to evaluate the neurologic status before LIF and at the time of discharge. Patient's sex, age, etiology of VBO, recanalization, symptom duration before LIF, and pretreatment mRS were correlated with posttreatment mRS. Multiple logistic regression analysis was used to identify independent variables for recanalization and neurologic outcome. RESULTS: The overall mortality was 43%. Complete recanalization was achieved in 99 (55%) patients and a partial recanalization in 35 (19%) patients, respectively. Recanalization was significantly associated with a favorable outcome (P < .001). The success of recanalization was negatively correlated with the volume of the thrombus (P < .001). No correlation was found between site and etiology of VBO and recanalization. Neurologic outcome correlated strongly with the pretreatment mRS (P < .001) and also with age (P < .02). Coma lasting less than 4.5 hours led to a positive trend toward a better outcome after univariate testing (P < .001). CONCLUSIONS: Success of recanalization and neurologic status before treatment predict neurologic outcome in patients with VBO. Thrombus volume has an adverse effect on the recanalization success.

Intraprocedural thrombus formation during coil placement in ruptured intracranial aneurysms: treatment with systemic application of the glycoprotein IIb/IIIa antagonist tirofiban.

BACKGROUND AND PURPOSE: When using detachable coils to treat intracranial aneurysms, thromboembolism is the most feared and frequently reported complication during or after endovascular therapy. The purpose of this study was to document the therapeutic effect of tirofiban on patency of the parent vessel, rate of rebleedings, and outcome of the patients in the setting of acute subarachnoidal hemorrhage. METHODS: A patient data base was retrospectively reviewed to identify patients in whom thrombus occurred during endovascular treatment of ruptured cerebral aneurysms within a 34-month period and who were treated with tirofiban. All patients underwent anticoagulation with heparin during endovascular treatment procedures. Sixteen patients (age range, 52.9 +/- 10.7 years; 10 women, 6 men) were identified with intraprocedural thrombus formation. The patency of the parent vessel was assessed in a retrospective analysis blinded to outcome. Eight patients received ventriculostomy and had a follow-up CT. RESULTS: Local nonocclusive thrombus at the coil surface was detected in 5 patients, in all of whom the thrombus was dissolved. In 10 patients, partial or total occlusion of the parent vessel occurred during the intervention; in 8 of these, the vessel was recanalized completely and in 2 drug administration was assisted by mechanical means. In 1 patient, however, the occlusion persisted. No periprocedural rebleedings of the ruptured aneurysm occurred; 3 of 8 ventriculostomies had clinically silent small local bleedings. CONCLUSION: The use of tirofiban in the setting of endovascular treatment of ruptured intracranial aneurysms to dissolve platelet aggregation seems relatively safe and effective.

Efficacy of stent angioplasty for symptomatic stenoses of the proximal vertebral artery.

BACKGROUND: To evaluate the safety and efficacy of stent angioplasty in the treatment of symptomatic arteriosclerotic stenoses of the proximal vertebral artery (VA). METHODS: Thirty-eight symptomatic stenoses of the vertebral origin were treated with flexible balloon-expandable coronary stents. Angiographic and clinical follow-up examinations were obtained in 26 patients at a mean of 11 months. RESULTS: The immediate post-procedural angiographic results showed no residual stenosis in 33 vessels and mild residual stenoses in five vessels. Periprocedurally, there were two asymptomatic technical complications and one TIA. During follow-up re-stenosis could be detected in 10 cases (36%), and vessel occlusions in two patients. Two stents were broken. One of the restenosis caused a TIA within the follow-up period. CONCLUSIONS: Flexible balloon-expandable coronary stents proved to be save and effective in preventing vertebrobasilar stroke but were incapable to preserve the proximal vertebral artery lumen. For the VA origine an adequate stent, self-expanding, bioresorbable, or drug-eluting has to be found.

High-resolution CT of the temporal bone in dysplasia of the auricle and external auditory canal.

PURPOSE: To determine CT findings in the external, middle, and inner ear of patients with microtia and external auditory canal dysplasia. METHODS: We used high-resolution CT, with multiplanar or axial 1-mm continuous sections, coronal or sagittal reformations, or low-dose spiral acquisitions, to examine 184 temporal bones of children with microtia. RESULTS: In cases of minor microtia, auditory canal stenosis was the most common associated abnormality; in those with major microtia, atresia was predominant. Middle ear malformations depended on the severity of the auricular anomalies. Inner ear changes could also be noted. Ossicle dysplasias occurred in 98% of patients (stapes, 72%), absence of the oval window in 36%, labyrinthine malformations in 13%, closed round window in 6%, facial canal displacement in up to 75%, and aberrations of the vascular canal in 38% of patients with third-grade auricular deformity. CONCLUSION: A variety of external, middle, and, less frequently, inner ear changes were detected in connection with microtia.

Dynamic CT perfusion imaging of acute stroke.

BACKGROUND AND PURPOSE: Because cerebral perfusion imaging for acute stroke is unavailable in most hospitals, we investigated the feasibility of a method of perfusion scanning that can be performed rapidly during standard cranial CT. Our aim was to identify the scanning parameters best suited to indicate tissue at risk and to measure a perfusion limit to predict infarction. METHODS: Seventy patients who had suffered stroke and had undergone cranial CT 0.5 to 12 hours (median, 3.75 hr) after the onset of symptoms participated in the study. While undergoing conventional CT, each patient received a bolus of iodinated contrast medium. Maps of time to peak (TTP), cerebral blood volume (CBV), and CBF were calculated from the resulting dynamically enhanced scans. These perfusion images were compared with follow-up CT scans or MR images showing the final infarctions. RESULTS: CBF maps predicted the extent of cerebral infarction with a sensitivity of 93% and a specificity of 98%. In contrast, CBV maps were less sensitive and TTP maps were less specific and also showed areas of collateral flow. Infarction occurred in all of the patients with CBF reduction of more than 70% and in half of the patients with CBF reduction of 40% to 70%. CONCLUSION: Dynamic CT perfusion imaging safely detects tissue at risk in cases of acute stroke and is a feasible method for any clinic with a third-generation CT scanner.

Intracranial bleeding rates associated with two methods of external ventricular drainage.

We investigated the risk of intracranial haemorrhage with two frequently performed methods of external ventricular drainage (EVD). Haemorrhage is believed to be a rare complication of such procedures, although in most studies reported in the literature standardised evaluation of computed tomography (CT) scans was not performed in all cases. Data were analysed retrospectively for 82 patients who had undergone percutaneous needle trephination and 92 who had undergone classic ventriculostomy. We found an overall bleeding risk with EVD of 9.4%. Most haematomas were small, and only one caused neurological symptoms. Therefore, the risk of symptomatic haemorrhage in this study was low (0.5%). Percutaneous needle trephination was associated with a higher risk of haemorrhage (12.2%) than classic ventriculostomy (6.5%), although differences were not statistically significant. We conclude from our results that small asymptomatic haemorrhages occur far more often after EVD than has generally been suspected. To compare the true risk of bleeding associated with different drainage methods requires controlled studies in which CT scans are evaluated in a standardised way.

Diffusion-weighted imaging of hyperacute cerebral hypoglycemia.

BACKGROUND AND PURPOSE: Cerebral hypoglycemia can result in reversible metabolic brain insults and can be associated with impaired diffusion disturbances. Our aim was to evaluate possible changes in DWI of the human brain during hyperacute short-term severe hypoglycemia. MATERIALS AND METHODS: Ten individuals scheduled for a clinical IST were examined with DWI while the test was performed. Venous blood glucose was continuously measured, and sequential DWI sequences were performed without interruption. Hypoglycemia was terminated with intravenous glucose administration when glucose levels were at ≤2.0 mmol/L. RESULTS: Blood glucose levels were lowered to a mean nadir of 1.75 ± 0.38 mmol/L. No alterations of cerebral diffusion could be observed in any individuals on DWI. CONCLUSIONS: Hyperacute short-term severe hypoglycemia does not induce visible changes in DWI of the human brain.

The Penumbra System: a mechanical device for the treatment of acute stroke due to thromboembolism.

BACKGROUND AND PURPOSE: Data from recent reports have indicated that mechanical thrombectomy may have potential as a treatment for acute ischemic stroke. The purpose of this study was to assess the safety and performance of the Penumbra System (PS): a novel mechanical device designed to reduce clot burden in acute stroke due to large-vessel occlusive disease. MATERIALS AND METHODS: A prospective, single arm, independently monitored and core laboratory adjudicated trial enrolled subjects with an acute neurologic deficit consistent with acute stroke, presenting within 8 hours of symptom onset and an angiographically verified occlusion (Thrombolysis in Myocardial Infarction [TIMI] grade 0 or 1) of a treatable intracranial vessel. The primary end point was revascularization of the target vessel to TIMI grade 2 or 3. Secondary end points were the proportion of subjects who achieved a modified Rankin Scale (mRS) score of 2 or less or a 4-point improvement on the National Institutes of Health Stroke Scale (NIHSS) score at 30-day follow-up, as well as all-cause mortality. RESULTS: Twenty-three subjects were enrolled, and 21 target vessels were treated in 20 subjects by the PS. At baseline, mean age was 60 years, mean mRS score was 4.6, and mean NIHSS score was 21. Postprocedure, all 21 of the treated vessels (100%) were successfully revascularized by the PS to TIMI 2 or 3. At 30-day follow-up, 9 subjects (45%) had a 4-point or more NIHSS improvement or an mRS of 2 or less. The all-cause mortality rate was 45% (9 of 20), which is lower than expected in this severe stroke cohort, where 70% of the subjects at baseline had either an NIHSS score of more than 20 or a basilar occlusion. CONCLUSION: Thus, early clinical experience suggests that the PS allows revascularization in certain subjects experiencing acute ischemic stroke.

Monitoring of clopidogrel-related platelet inhibition: correlation of nonresponse with clinical outcome in supra-aortic stenting.

BACKGROUND AND PURPOSE: Clopidogrel and aspirin are antiplatelet medications used in patients intended for endovascular stent placement. Although various studies have investigated individual responsiveness to clopidogrel in patients undergoing coronary interventions, there are no studies regarding patients undergoing stent placement of supra-aortic arteries supplying the brain. We analyzed platelet function in a near-patient setting to determine the effects of antiplatelet treatment in neurologic patients and correlated the results with clinical outcome after stent placement. MATERIALS AND METHODS: The platelet function of 50 consecutive patients scheduled for neuro-interventional stent placement procedures was assessed by using point-of-care testing. All of the patients had symptomatic arteriosclerotic lesions. Clopidogrel effects were tested by impedance aggregometry. Fifty healthy blood donors without clopidogrel medication served as the control group. RESULTS: Reference values for responders and nonresponders were established from the results of the healthy control group. Fourteen (28%) of 50 neurologic patients were stratified as clopidogrel nonresponders. Adverse events were registered in 5 (10%) of 50 patients, 1 of them with a permanent neurologic deficit (1 of 50 [2%]). All 5 of the patients with adverse events were nonresponders. There was a statistically significant correlation between adverse events and clopidogrel nonresponse (Fisher exact test, P = .001). CONCLUSION: A significant rate of clopidogrel nonresponders could be identified in the treated patients. Our data strongly suggest a correlation of insufficient clopidogrel-related platelet inhibition with an increased risk of thromboembolic events in supra-aortic stent placement.

[Management of acute basilar artery occlusion]. / Management des akuten Basilarisverschlusses.

Basilar artery thrombosis is a life-threatening condition whose unfavorable spontaneous prognosis can only be improved by early detection and subsequent aggressive recanalization therapy. The therapeutic approach has not yet been standardized and ranges from intravenous thrombolytic therapy with pharmacological agents to experimental procedures of mechanical endovascular recanalization, but the availability of the treatment approach and location of the occlusion determine the procedure in individual cases. Multicenter studies will have to clarify which bridging therapy (single administration of i.v. rt-PA or in combination with GPIIbIIIb inhibitors) before endovascular treatment is superior in terms of effectivity and complication rate.

[Diagnosis and therapy of basilar artery occlusion]. / Diagnostik und Therapie der Basilaristhrombose.

In view of the poor prognosis for untreated patients with basilar artery occlusion, rapid delivery of effective treatment has the highest priority. Early recanalization by intra-arterial thrombolysis can improve the outcome in some patients. Apart from this method, specialized centers are increasingly using mechanical devices and glycoprotein IIb/IIIa inhibitors to achieve recanalization. This review focuses on current developments in the diagnosis and treatment of acute basilar artery occlusion.

[Diagnosis of acute subarachnoid hemorrhage at 1.5 Tesla using proton-density weighted FSE and MRI sequences]. / Nachweis der akuten Subarachnoidalblutung. FLAIR- und Protonendichte-gewichtete MRT-Sequenzen bei 1.5 Tesla.

PURPOSE: To evaluate MR imaging at 1.5 Tesla in patients suffering from acute subarachnoid hemorrhage (SAH) using proton-density weighted (PDW) fast spin echo (FSE) and fluid attenuated inversion recovery (FLAIR) sequences. METHODS: 19 patients suffering from acute SAH as diagnosed by CT were studied 6 h to 3 days after hemorrhage. 10 patients without SAH were studied as a control group. The presence of subarachnoid blood as well as possible artifacts was recorded. RESULTS: In all 19 patients subarachnoid hemorrhage was detected on both FLAIR and PDW images (100%). On the FLAIR images, the cerebral ventricles were partially obscured by flow artifacts in 7 of 19 patients, the basal cisterns in 6 of 19 patients. In 4 of these 13 regions blood was diagnosed on both PDW and CT images, while in the other 9 regions both PDW and CT were unremarkable. CONCLUSION: The sensitivity of MRI at 1.5 Tesla in the diagnosis of subarachnoid hemorrhage is comparable to CT. The combination of FLAIR and PDW FSE sequences helps to avoid false-positive results caused by flow artifacts.

[Diagnosis and treatment of cranial arteriovenous dural fistulas]. / Diagnostik und Therapie kranialer arteriovenöser Durafisteln.

DAVF are difficult to recognize with CT- or MR-imaging. Diagnosis is often possible by arterial MRA. The type of the venous drainage as demonstrated by DSA is relevant for the clinical decision. Most often the endovascular occlusion of the affected venous segment a suitable therapeutical approach.

Serial CT and MRI of ischaemic cerebral infarcts: frequency and clinical impact of haemorrhagic transformation.

The frequency, predisposing factors and clinical consequences of haemorrhagic infarcts and damaged blood-brain barrier as shown by contrast enhancement (CE) in ischaemic cerebral infarcts are controversial. We prospectively compared the sensitivity of CT and MRI to haemorrhagic transformation (HT) and CE. We also wished to investigate the clinical significance of HT and factors possibly associated with it. We studied 36 patients with acute ischaemic infarcts in the middle cerebral artery territory during the first 2 weeks after the ictus. After CT and rating of the neurological deficit on admission, serial examinations with clinical neuromonitoring, contrast-enhanced CT and MRI were done on the same day. The occurrence and severity of HT were correlated with CE, stroke mechanism, infarct size, development of neurological deficits and antithrombotic treatment. The frequency of HT detected by MRI was 80%. CE usually preceded HT or was seen simultaneously. MRI had a higher sensitivity than CT to HT and CE. Severity of HT was positively correlated with infarct size (P < 0.01). HT had no influence on patient's neurological status. Neither the type of antithrombotic treatment nor the stroke mechanism was associated with the severity of HT. No parenchymal haemorrhage occurred.

Detection of hyperacute parenchymal hemorrhage of the brain using echo-planar T2*-weighted and diffusion-weighted MRI.

We investigated the usefulness of echo-planar imaging (EPI) as well as T2*-weighted and diffusion-weighted MRI (DWI) to identify hyperacute hemorrhage (within 24 h after ictus) in the brain. Seven patients were examined 3.5 to 24 h after onset of symptoms using a whole-body 1.5-T MR system. Two diffusion-weighted sequences were run to obtain isotropic and anisotropic diffusion images. Apparent diffusion coefficients (ADC) were calculated from the isotropic diffusion images. All DWI images as well as the T2*-weighted EPI images showed the hematomas as either discrete, deeply hypointense homogeneous lesions, or as lesions of mixed signal intensity containing hypointense areas. We conclude that even in the early phase after hemorrhage, sufficient amounts of paramagnetic deoxyhemoglobin are present in intracerebral hemorrhages to cause hypointensity on EPI T2*-weighted and DWI images; thus, use of ultrafast EPI allows identification of intracerebral hemorrhage.

Neurological and neuropsychological examination and outcome after use of an intra-aortic filter device during cardiac surgery.

Cerebral embolization of particles after cardiac surgery is frequently associated with neurological deficits. Aortic crossclamp manipulation seems to be the most significant cause of emboli release during cardiac surgery. The goal of this study was to demonstrate whether the use of an intra-aortic filter device has an effect on the magnet resonance imaging (MRI) and functional neurological outcome. Twenty-four patients undergoing cardiosurgical procedures using cardiopulmonary bypass (CPB) were selected: coronary artery bypass graft (CABG) surgery (n = 17), aortic valve replacement (AVR) surgery (n = 4) or combined procedures (n = 3). Patients were evaluated by diffusion weighted MRI of the brain, neurological examination and neuropsychological assessment regarding alertness as well as divided and selective attention before and five to seven days after surgery. The patients were divided into two groups. In group I, 12 patients received a filter through a modified 24 F arterial cannula immediately before the aortic crossclamp was released. Filters remained in the aorta until CPB was discontinued. Intraoperatively, bilateral middle cerebral artery transcranial Doppler (TCD) was monitored at baseline, at the beginning of CPB, at a timepoint when the aorta was crossclamped, when the filter was inserted and while the crossclamp was switched to partial clamping until the CPB was discontinued. TCD was used for detection of microembolic signals (MES). The captured material in the filter was examined histologically. Twelve patients served as controls without aortic filtration (group II). The MRI of the brain did not show any diffusion alterations in either group before or after surgery. No patient developed a focal neurological deficit or stroke. Intraoperative quantitative MES detection revealed a four to tenfold increase in patients of group I compared with group II (5-6 versus 0.5-1 MES/min) during the filter dwell time. There was no consistent pattern regarding the neurobehavioural sequelae. Filters showed arteriosclerotic debris in 75% of the patients. The use of the intra-aortic filter device did not show a positive effect on neurological, neuroradiographical and neuropsychological outcomes. The increase of the MES rate in group I patients may be due to microbubbles generated as microcavitations by the filter or the aortic filter cannula. The intra-aortic filter was able to capture atheromatous material in 75% of the patients.