Eren Erdem

Microbubble Potentiated Ultrasound as a Method of Stroke Therapy in a Pig Model: Preliminary Findings

PURPOSE Low-frequency ultrasound (LFUS) with intraarterial or intravenous microbubbles can recanalize thrombosed dialysis grafts and arteries. A similar method for declotting intracranial arteries in an animal model has been developed. MATERIALS AND METHODS Swine underwent selective cerebral angiography, and 1 mL of 2-6 hour old clot was placed in one ascending pharyngeal artery and rete mirabile. This occluded the primary brain blood supply from the rete mirabile in the base of the skull. Human albumin octafluoropropane microbubbles were injected through the same catheter in 0.5-1.0-mL doses for a total of 4.5 mL in 21 minutes. Transcutaneous pulsed-wave 1-MHz ultrasound was administered through a temporal approach using 2.2 W/cm(2). Repeated angiography was performed through 24 minutes. Saline controls underwent an identical process on the opposite side. Declotting was graded on a scale of 0-4, and flow used the 0-3 thrombolysis in myocardial infarction (TIMI) scale. Success was defined as declotting of grade >/= 3 (>70% clearing) with flow of >/= 2. RESULTS Seven pigs received 14 declotting sequences. Average clot age was 217 minutes. Average declotting score was 3.1, and flow was 2.1 for microbubbles and 1.4 and 0.1 for saline controls, P =.016 in each. Success occurred with microbubbles in six of seven attempts and in controls in zero of seven attempts, P =.031. CONCLUSIONS LFUS with microbubble augmentation rapidly lyses intracranial clot and restores flow at ultrasound ranges similar to those required in humans. Further development of this possible acute stroke therapy is justified.

Symptomatic and Silent Ischemia Associated With Microsurgical Clipping of Intracranial Aneurysms Evaluation With Diffusion-Weighted MRI

Background and Purpose— Silent ischemic events are known to occur during diagnostic and interventional endovascular procedures between 10% and 69% of the time. The occurrence of silent and symptomatic ischemic events in the surgically treated population is not known, although atherosclerotic changes of intracranial vessels or within the aneurysms wall or neck area are seen often during surgery. Methods— Patients with unruptured and ruptured intracranial aneurysms treated by microsurgical clipping were prospectively evaluated with MRI using diffusion-weighted imaging sequences before and within 24 hours after surgery. Patients were evaluated clinically before and after surgery. During surgery, the overall and maximal time of temporary occlusion as well as the total number of temporary and finally applied clips was noted. Diffusion-weighted images were analyzed with determination and characterization of diffusion-weighted imaging abnormalities. Results— Thirty-six patients with 51 aneurysms were included. One symptomatic and 5 silent ischemic lesions were found in 5 patients. This represents a risk of silent ischemia of 9.8% per treated aneurysm and a risk of symptomatic stroke of 2%. The most significant risk factor in increasing order was: age (P<0.05), presence of thrombus (P<0.05), number of final clips applied (P<0.05), number of temporary clips used (P<0.01), total time of temporary clip occlusion (P<0.001), and maximal time of temporary occlusion (P<0.001). Conclusions— The risk of silent and symptomatic ischemic events during microsurgical clipping of intracranial aneurysms seems to be low. Microsurgical clipping is safe and should continue to be strongly considered as a treatment option.

MRI-validation of SEP monitoring for ischemic events during microsurgical clipping of intracranial aneurysms

OBJECTIVE During surgical clipping of intracranial aneurysms, reduction in SEP amplitude is thought to indicate cortical ischemia and subsequent neurological deficits. Since the sensitivity of SEP is questioned, we investigated SEP with respect to post-operative ischemia. METHODS In 36 patients with 51 intracranial aneurysms, clinical evaluation and diffusion-weighted MRI (DWI) was performed before and within 24h after surgery. During surgery, time of temporary occlusion was recorded. MRI images were reviewed for signs of ischemia. RESULTS For 43 clip applications (84%), we observed neither pathologic SEP events nor ischemia in MRI. In two cases where reduction lasted >10 min after clip release, SEP events correlated with ischemia in the MRI. Only one of the ischemic patients was symptomatic and developed a transient hemiparesis. CONCLUSIONS While pathologic SEP events correlated with visible ischemia in MRI only in two cases with late SEP recovery, ischemia in MRI may have been transient or may not have reached detection threshold in the other cases, in agreement with the absence of permanent neurological deficits. SIGNIFICANCE In complex aneurysm cases, where prolonged temporary occlusion is expected, SEP should be used to detect ischemia at a reversible stage to improve the safety of aneurysm clipping.

Radiofrequency-targeted vertebral augmentation for the treatment of vertebral compression fractures as a result of multiple myeloma.

Study Design. A retrospective review of a consecutive population of patients treated with radiofrequency-targeted vertebral augmentation (RF-TVA) for malignant vertebral compression fractures (VCFs). Objective. To investigate the safety and efficacy of RF-TVA in patients with malignant VCFs. Summary of Background Data. The use of polymethylmethacrylate (PMMA) in vertebroplasty and balloon kyphoplasty for patients with recalcitrant pain after acute VCFs is shown to be safe, successful in stabilizing the VCF, and effective for the relief of pain after osteoporotic and malignant VCFs. RF-TVA using targeted cavity creation and ultrahigh viscosity PMMA delivery with a long handling time was developed to address the potential adverse issues that arise with vertebroplasty and balloon kyphoplasty. Methods. Between December 2008 and May 2009, a consecutive series of 66 RF-TVA procedures were performed by the authors for VCF secondary to multiple myeloma. Pre- and postoperatively, a standard 10-point visual analogue scale was used to assess back pain. Pain medication use and activity categories were defined and monitored for changes before and after RF-TVA. All patients were followed for 6 months postoperatively. Results. At 6 months postoperatively, significant improvement in pain, activity, and narcotic use was observed. There were no pulmonary or neurological complications, and one patient had radiographical evidence of asymptomatic leakage of PMMA into the vertebral disc space. Conclusion. We report optimum safety and efficacy results in the treatment of malignant VCFs with a novel RF-TVA technique in which controlled delivery of an ultrahigh viscosity PMMA is used for fracture stabilization. The deposition of PMMA with RF-TVA is predictable and uniform, and can be performed without the PMMA handling constraints that may be encountered with vertebroplasty and balloon kyphoplasty. The safety and efficacy we report with RF-TVA achieved equivalency with other methods of treatment for VCF stabilization.

The Impact of Minimizing Brain Retraction in Aneurysm Surgery: Evaluation Using Magnetic Resonance Imaging

BACKGROUND:Recent advances in skull base and microsurgical techniques minimize the need for brain retraction. OBJECTIVE:We studied the impact of such techniques in 36 patients (51 aneurysms) using magnetic resonance imaging (MRI). METHODS:Preoperative and 24 hours postoperative MR imaging was performed in patients undergoing microsurgical clipping of intracranial aneurysms. Images were evaluated for parenchymal signal changes. During surgery, use and time of brain retraction were recorded. The degree of cortical injury was quantified using a 0 to 3 scale (grade 0 = normal surface; 1 = pial/arachnoidal damage; 2 = gray matter injury; 3 = contusion/necrosis). RESULTS:Brain retraction by use of a brain spatula was used in all patients. Retraction times ranged from 14 to 290 minutes (mean, 84.1). Cortical surface changes were grade 0 in 86% and grade 1 in 14%; none showed grade 2 or 3 changes. In the postoperative MRI, 4 patients presented with parenchymal alterations, 4 with edema (11.1%), and 1 patient had additional contusion (2.8%). All lesions were confined to the temporal pole. The grade of cortical surface changes was not related to lesions found on MR imaging. No patients showed retraction-related neurological deficits. CONCLUSION:The incidence of evident mechanical parenchymal injury (infarction or contusion) is very low when appropriate microsurgical and skull base techniques are used. Minor pia-arachnoid injury should nevertheless continue to be attended through future advances.

Basilar artery occlusion treated with mechanical thrombectomy beyond eight hours with successful recanalization and good functional outcomes.

Patient 1 A 67-year-old man with hypertension and hypercholesterolemia developed sudden right hemiparesis, dysarthria and lethargy. He presented to our institution 10 h following symptom onset. During the previous 3 weeks, he had had 2 episodes of transient leg weakness and headache. Neurological examination revealed severe lethargy, right gaze palsy, right facial weakness, deviation of the tongue to the right and right hemiparesis. The National Institute of Health Stroke Scale score was 15. Brain magnetic resonance imaging showed acute infarcts in the left pontine tegmentum, medial occipital and parietal lobes and cerebellum. Digital subtraction angiography, performed 17 h after the stroke, revealed midbasilar occlusion. Mechanical thrombectomy, using the X6 Merci retriever, followed by balloon angioplasty of a midbasilar artery stenosis was successfully performed, without procedure-related complications. Heparin was administered for 24 h after this procedure. Aspirin had been started upon admission. There is a growing interest in mechanical endovascular therapy for stroke patients who are ineligible for, or do not respond to, intravenous thrombolytic therapy. The effect of such interventions on functional outcome is yet to be proven. However, a narrow time window has limited wider use of these techniques, especially in the context of randomized trials. We illustrate 2 patients who underwent late but successful mechanical thrombectomy Published online: May 13, 2009

Successful intra-arterial thrombolytic therapy for a right middle cerebral artery stroke in a 2-year-old supported by a ventricular assist device

Embolic stroke is a common complication in patients on ventricular assist devices in both adults and children. The reported incidence of strokes in children supported by VAD’s varies from 7 to 38%. The rapid increase in recent years in the availability of both adult and pediatric VADs will likely add to the overall prevalence of strokes in patients being bridged to heart transplant. Strokes in this population can be lethal as they frequently necessitate withdrawal of the extracorporeal device support and withdrawal from the organ transplant waiting list. We present a case of a fully anti‐coagulated 29‐month‐old supported on a Berlin EXCOR LVAD (Berlin, Germany) with embolic stroke which was treated successfully with direct thrombolysis with recombinant tissue plasminogen activator. This is the first report which uses intra‐arterial thrombolytics while on a ventricular assist device in a pediatric patient.

Arteriovenous fistula originating from proximal part of the anterior cerebral artery

Intracerebral arteriovenous fistulas of the brain may be misdiagnosed as arteriovenous malformation. There are only a few reports in the literature about this concept and to the best of our knowledge this is the first case arising from the proximal part of the anterior cerebral artery in association with an aneurysm that ruptured. A 64-year-old man presented with subarachnoid hemorrhage. The patient was neurologically intact. Cerebral angiography and magnetic resonance imaging of the patient revealed a small arteriovenous malformation of the brain involving the region of gyrus rectus and the posteromedial aspect of the orbitofrontal gyrus in addition to an aneurysmal dilatation within the malformation. An arteriovenous fistula arising from the junction of the A1 and A2 segments of the right anterior cerebral artery connected to a vein that has tributaries spreading over the fronto-orbital gyrus and gyrus rectus, were observed during surgery. The patient was successfully treated with clip ligatation of the fistula. Intracerebral arteriovenous fistulas are rare lesions. They may easily be misdiagnosed as arteriovenous malformations. There preoperative consideration in the differential diagnosis can help to decide the most appropriate treatment option.

Vertebral augmentation in the treatment of pathologic compression fractures in 792 patients with multiple myeloma

Vertebral augmentation in the treatment of pathologic compression fractures in 792 patients with multiple myeloma

Endovascular management of symptomatic vertebral artery origin stenosis in the presence of an acute thrombus

A woman in her early 60s with hypertension and hyperlipidemia was undergoing investigations for anemia of unknown etiology. She developed a sudden reduction in visual acuity and bilateral visual field impairment. MRI and angiography revealed acute infarcts in the posterior circulation and severe narrowing of the left vertebral artery origin. Digital subtraction angiography demonstrated a high-grade stenosis of the left vertebral artery origin with a thrombus just distal to the stenosis. The patient developed recurrent infarcts while on antithrombotic therapy. The lesion was successfully treated by vertebral artery origin angioplasty and stenting (VOAS) using a flow reversal technique and distal embolic protection. She was discharged to a rehabilitation facility 4 days later without worsening or new neurological deficits. A search of the literature yielded a similar report managed with anticoagulation and subsequent VOAS after complete lysis of the thrombus. Our report highlights the technique, safety and feasibility of VOAS in the presence of a thrombus using a flow reversal technique and distal protection.