Safety of direct injection of oligodendrocyte progenitor cells into the spinal cord of uninjured Göttingen minipigs

OBJECTIVE

This study was conducted as a final proof-of-safety direct injection of oligodendrocyte progenitor cells into the uninjured spinal cord prior to translation to the human clinical trials.

METHODS

In this study, 107 oligodendrocyte progenitor cells (LCTOPC1, also known as AST-OPC1 and GRNOPC1) in 50-μL suspension were injected directly into the uninjured spinal cords of 8 immunosuppressed Göttingen minipigs using a specially designed stereotactic delivery device. Four additional Göttingen minipigs were given Hanks' Balanced Salt Solution and acted as the control group.

RESULTS

Cell survival and no evidence of histological damage, abnormal inflammation, microbiological or immunological abnormalities, tumor formation, or unexpected morbidity or mortality were demonstrated.

CONCLUSIONS

These data strongly support the safety of intraparenchymal injection of LCTOPC1 into the spinal cord using a model anatomically similar to that of the human spinal cord. Furthermore, this research provides guidance for future clinical interventions, including mechanisms for precise positioning and anticipated volumes of biological payloads that can be safely delivered directly into uninjured portions of the spinal cord.

Transforaminal lumbar interbody fusion using a novel minimally invasive expandable interbody cage: patient-reported outcomes and radiographic parameters

OBJECTIVE

The goal of this study was to evaluate the clinical and radiographic outcomes of a novel multidirectional in situ expandable minimally invasive surgery (MIS) transforaminal lumbar interbody fusion (TLIF) cage.

METHODS

A retrospective analysis of 69 consecutive patients undergoing a 1- or 2-level MIS TLIF using an expandable cage was performed over a 2-year period. Standard MIS techniques with pedicle screw fixation were used in all cases. Upright lateral dynamic flexion/extension radiographs were reviewed prior to and at 1 year after surgery. Clinical metrics included numeric rating scale for back and leg pain, Oswestry Disability Index, and the SF-12 and VR-12 physical and mental health surveys. Radiographic parameters included anterior and posterior disc height, neuroforaminal height, spondylolisthesis, segmental lordosis, lumbar lordosis, and fusion rate.

RESULTS

A total of 69 patients representing 75 operative levels met study inclusion criteria. The mean patient age at surgery was 63.4 ± 1.2 years, with a female predominance of 51%. The average radiographic and clinical follow-ups were 372 and 368 days, respectively. A total of 63 patients (91%) underwent 1-level surgery and 6 patients (9%) underwent 2-level surgery. Significant reductions of numeric rating scale scores for back and leg pain were observed-from 6.1 ± 0.7 to 2.5 ± 0.3 (p < 0.0001) and 4.9 ± 0.6 to 1.9 ± 0.2 (p < 0.0001), respectively. A similar reduction in Oswestry Disability Index from 38.0 ± 4.6 to 20.0 ± 2.3 (p < 0.0001) was noted. Likewise, SF-12 and VR-12 scores all showed statistically significant improvement from baseline (p < 0.001). The mean anterior and posterior disc heights improved from 8.7 ± 1.0 mm to 13.4 ± 1.5 mm (p = 0.0001) and 6.5 ± 0.8 mm to 9.6 ± 1.1 mm (p = 0.0001), respectively. Neuroforaminal height improved from 17.6 ± 2.0 mm to 21.9 ± 2.5 mm (p = 0.0001). When present, spondylolisthesis was, on average, reduced from 4.3 ± 0.5 mm to 1.9 ± 0.2 mm (p = 0.0001). Lumbar lordosis improved from 47.8° ± 5.5° to 58.5° ± 6.8° (p = 0.2687), and no significant change in segmental lordosis was observed. The overall rate of radiographic fusion was 93.3% at 1 year. No perioperative complications requiring operative revision were encountered.

CONCLUSIONS

In this series of MIS TLIFs, use of this novel interbody cage was shown to be safe and effective. Significant improvements in pain and disability were observed. Effective and durable restoration of disc height and neuroforaminal height and reduction of spondylolisthesis were obtained, with concurrent gains in lumbar lordosis. Taken together, this device offers excellent clinical and radiographic outcomes via an MIS approach.

High mobility group box protein-1 promotes cerebral edema after traumatic brain injury via activation of toll-like receptor 4

Traumatic brain injury (TBI) is a major cause of mortality and morbidity worldwide. Cerebral edema, a life-threatening medical complication, contributes to elevated intracranial pressure (ICP) and a poor clinical prognosis after TBI. Unfortunately, treatment options to reduce post-traumatic edema remain suboptimal, due in part, to a dearth of viable therapeutic targets. Herein, we tested the hypothesis that cerebral innate immune responses contribute to edema development after TBI. Our results demonstrate that high-mobility group box protein 1 (HMGB1) was released from necrotic neurons via a NR2B-mediated mechanism. HMGB1 was clinically associated with elevated ICP in patients and functionally promoted cerebral edema after TBI in mice. The detrimental effects of HMGB1 were mediated, at least in part, via activation of microglial toll-like receptor 4 (TLR4) and the subsequent expression of the astrocytic water channel, aquaporin-4 (AQP4). Genetic or pharmacological (VGX-1027) TLR4 inhibition attenuated the neuroinflammatory response and limited post-traumatic edema with a delayed, clinically implementable therapeutic window. Human and rodent tissue culture studies further defined the cellular mechanisms demonstrating neuronal HMGB1 initiates the microglial release of interleukin-6 (IL-6) in a TLR4 dependent mechanism. In turn, microglial IL-6 increased the astrocytic expression of AQP4. Taken together, these data implicate microglia as key mediators of post-traumatic brain edema and suggest HMGB1-TLR4 signaling promotes neurovascular dysfunction after TBI.

Single Stage versus Multi-staged Stent-assisted Endovascular Repair of Intracranial Aneurysms

BACKGROUND

Stent-assisted coiling of intracranial aneurysms is performed either as a single-stage or a multi-staged procedure. The objective of our study is to compare the complications between the in single-stage versus the multi-staged stent-assisted coiling of intracranial aneurysm.

METHODS

From January 2003 to January 2010, consecutive patients treated with intracranial stent for aneurysms were prospectively enrolled. Patients' demographics including cerebrovascular risk factors, aneurysms size and locations were collected. Technical and clinical complications as well as outcomes were measured. Data were analyzed retrospectively using SPSS software version 11.5.

RESULTS

87 patients (87 aneurysms) with a mean of 51.2 ± 13.6 years were treated with 90 intracranial (Neuroform 74, Enterprise 16) stents, single-stage 37 (42.5%) and multi-staged 50 (57.5%). Eight adverse events were observed without any mortality, 6 of which were in the single-stage group-rupture of aneurysm in 2, and thrombo-embolic events in 4. Both rupture occurred in basilar artery bifurcation aneurysms, required ventriculostomy and resuscitations. In single-stage, asymptomatic intra-operative stent thrombosis developed in one, symptomatic stent thrombosis in one on day 14, transient ischemic attack on day 6 and immediate post operative stroke in one. Only two minor strokes were observed in the multi-staged group, one on post-procedure day 7 and other on day 60. Majority of the patients had good outcomes including those with events.

CONCLUSION

Our study revealed that single-stage stent-coiling technique is associated with a higher rate of complications than multistaged procedure. Therefore, staging the procedure may be an option whenever possible.

Progressive occlusion of aneurysms in Neuroform Stent-assisted treatment of intracranial aneurysms

INTRODUCTION

The long term effect of Neuroform stent in progressive occlusion of intracranial aneurysms is not yet completely understood. Here the effect of the Neuroform stent in progressive occlusion of intracranial aneurysms and clinical outcome is reported.

METHODS

Consecutive patients treated with the Neuroform stent from January 2003 to July 2007 were prospectively enrolled. Patients' demographics, immediate and delayed rate of occlusion, and clinical outcomes using the National Institution of Health Stroke Scale (NIHSS) and the Glasgow Outcome Scale (GOS) were recorded.

RESULTS

Neuroform stent placement was attempted in 72 patients, including 10 ruptured cases. However, stent placement could not be accomplished in two patients who were not included for analysis. Mean age was 50 ± 14 years and mean aneurysm diameter was 10.28 ± 5.9 mm. Immediate complete occlusion was observed in 31 (44%), neck remnants in 29 (41%) and subtotal occlusion in 10 (14%). Angiographic follow-up was available in 59 cases; complete occlusion was observed in 48/59 (81%), neck remnant in 7/59 (13%) and recanalisation in 4/49 (7%). Of 39 patients with immediate incomplete obliteration, progressive complete occlusions were achieved in 25/31 (81%), no changes in two and recanalisation in four cases. The majority of patients had good outcomes (GOS 1 or NIHSS 0 in 66/70 (94%), GOS 2 or NIHSS 2 in one patient and GOS 3 or NIHSS 4 in three at the 90 day follow-up visit.

CONCLUSIONS

The Neuroform stent assisted neck remodelling technique improves progressive obliteration of intracranial aneurysms with a low recanalisation rate and good clinical outcome.

Angioplasty for cerebral vasospasm from eclampsia

BACKGROUND

Neurological deterioration in eclampsia is considered to be secondary to cerebral vasospasm. Magnesium sulfate therapy improves symptoms and controls seizures, possibly related to its vasorelaxive effects in spastic arteries. Some cases, however, are refractory to magnesium therapy. To our knowledge, there is no report of angioplasty for vasospasm from eclampsia in the literature.

METHODS

A 27-year-old woman presented 10 days postpartum with severe mental status changes and left arm and bilateral leg weakness that were refractory to magnesium therapy. Cerebral angiography demonstrated diffuse, severe vasospasm. We treated her with angioplasty of the bilateral middle and posterior cerebral arteries, basilar artery, and bilateral internal carotid arteries.

RESULTS

Angioplasty resulted in excellent angiographic improvement. The patient immediately became responsive and appropriate with improved strength in all extremities. She continued to improve throughout her hospital stay and was discharged 10 days postangioplasty.

CONCLUSIONS

Cerebral angioplasty is an effective treatment for vasospasm from eclampsia refractory to magnesium therapy. Angiography should be considered early in the course of neurological deterioration, but delayed therapy may also be effective.

Role of conventional angiography in evaluation of patients with carotid artery stenosis demonstrated by Doppler ultrasound in general practice

BACKGROUND AND PURPOSE

Previous studies have suggested that patients with carotid stenosis who are candidates for endarterectomy can be effectively identified on the basis of carotid Doppler ultrasound alone. Before widespread acceptance of this policy, the accuracy of carotid Doppler ultrasound outside selected centers and clinical trials needs to be evaluated. We performed a 12-month prospective study to evaluate the accuracy of Doppler ultrasound in identifying patients for carotid intervention in general practice settings.

METHODS

Each patient referred to our endovascular service for diagnostic angiography to evaluate for carotid stenosis was interviewed and examined by a neurologist. Subjects consisted of symptomatic patients with >/=50% stenosis and asymptomatic patients with >/=60% stenosis by Doppler ultrasound. Information pertaining to demographic and cerebrovascular risk factors and the results of the carotid Doppler ultrasound were recorded. The severity of stenosis on angiograms was measured with North American Symptomatic Carotid Endarterectomy Trial criteria by a blinded observer. The results of both studies were compared to determine the relative accuracy of ultrasound results.

RESULTS

Of 130 patients (mean age, 69+/-8.8 years) who met Doppler ultrasound criteria, 22 (17%) and 8 patients (6%) were found to have 30% to 49% or <30% stenosis by angiography, respectively. The positive predictive value of carotid Doppler ultrasound for identifying appropriate symptomatic candidates for carotid intervention (angiographic stenosis >/=50%) was 80%, with a false-positive value of 20%. The positive predictive value of carotid Doppler ultrasound for identifying appropriate asymptomatic candidates for carotid intervention (angiographic stenosis >/=60%) was 59%, with a false-positive value of 41%. Carotid endarterectomy or angioplasty and stent placement were undertaken subsequently in 60 (46%) of the patients. In 94 patients who underwent cerebral angiography alone, no complications were observed.

CONCLUSIONS

The present accuracy of carotid Doppler ultrasound in general practice does not justify its use as the sole basis of selecting appropriate patients for carotid intervention. Given the relatively low rate of associated morbidity with present day techniques, additional confirmatory studies such as angiography should be performed in every patient before a decision regarding intervention is made.

Angioplasty of intracranial occlusion resistant to thrombolysis in acute ischemic stroke

OBJECTIVE

Thrombolysis has been demonstrated to improve revascularization and outcome in patients with acute ischemic stroke. Many centers now apply thrombolytic therapy locally via intra-arterial infusion. One therapeutic benefit is the ability to cross soft clots with a guidewire and to perform mechanical thrombolysis. In some instances, reopened arteries reocclude as a result of either thrombosis or vasospasm. We report the use of balloon angioplasty during thrombolysis for acute stroke.

METHODS

From June 1995 through June 1999, 49 patients underwent intra-arterial therapy for acute stroke. In this group, nine patients (seven men and two women) were treated with balloon angioplasty after inadequate recanalization with thrombolytic infusion. The mean age of these patients was 67.9 years. Nine matched control patients who underwent thrombolysis alone without angioplasty were chosen for comparison.

RESULTS

In the group of nine patients who had angioplasty, the mean National Institutes of Health Stroke Scale score at presentation was 21.8 +/- 5.4. Four patients had residual distal occlusion after angioplasty, and one patient had a hemorrhagic conversion. Of the five patients in which recanalization was successful, none had reocclusion of the balloon-dilated vessel. The mean score at 30 days for the five survivors was 12.6 +/- 14.9, for an improvement of 7.0 +/- 14.2. Among the nine control patients, the mean score at presentation was 20.3 +/- 5.2; the mean score at 30 days for the five survivors was 19.4 +/- 7.7, for an improvement of 4.2 +/- 7.8.

CONCLUSION

In our experience, balloon angioplasty is a safe, effective adjuvant therapy in patients who are resistant to intra-arterial thrombolysis. The use of balloon angioplasty may prevent reocclusion in a stenotic artery and permit distal infusion of thrombolytic agents.

Endovascular treatment of intracranial aneurysms by using Guglielmi detachable coils in awake patients: safety and feasibility

OBJECT

Embolization of intracranial aneurysms performed using Guglielmi detachable coils (GDCs) is performed with the patient in a state of general anesthesia at most centers. Such an approach does not allow intraprocedural evaluation of the patient's neurological status and carries additional risks associated with general anesthesia and mechanical ventilation. At the authors' institution, GDC embolization of intracranial aneurysms is performed in awake patients after administration of sedative and analgesic agents (midazolam, fentanyl, morphine, and/or hydromorphone). To determine the feasibility and safety of this approach, the authors have retrospectively reviewed their clinical experience.

METHODS

The authors reviewed the medical records of all patients in whom GDC embolization for the treatment of intracranial aneurysms was undertaken between February 1, 1990 and October 31, 1999. Clinical presentation, medical comorbidities, anesthetic agents used, intraprocedural complications, and final procedural outcome were recorded for each patient. Guglielmi detachable coil embolization was attempted in the awake patient in 150 procedures. Among 92 procedures for unruptured aneurysms, 75 (82%) were completed without complications. Four procedures were completed with complications. Of the 92 procedures, 13 were aborted due to patient uncooperativeness (one patient), complications (three patients), morphological characteristics of the aneurysm or surrounding vessels that made embolization technically difficult (eight patients), or vasospasm (one patient). Among 58 procedures for ruptured aneurysms, the procedure was completed without complication in 48 cases (83%). The procedure was completed with complications in five cases and two patients required induction of general anesthesia during the procedure. Five procedures were aborted because morphological characteristics of the aneurysm or surrounding vessels made embolization technically difficult (two patients) or because of aneurysm rupture (two patients) or the appearance of a transient neurological deficit (one patient).

CONCLUSIONS

Embolization of intracranial aneurysms performed using GDCs in the awake patient appears to be safe and feasible and allows intraprocedural evaluation of the patient. Potential advantages, including decreased cardiopulmonary morbidity rates, shorter hospital stay, and lower hospital costs, still require confirmation by a direct comparison with other anesthetic procedures.

Open-label phase I clinical study to assess the safety of intravenous eptifibatide in patients undergoing internal carotid artery angioplasty and stent placement

OBJECTIVE

Eptifibatide, a competitive platelet glycoprotein IIb-IIIa receptor inhibitor with high selectivity and a short half-life, has been demonstrated to reduce the risk of ischemic events associated with coronary interventions. However, its role in neurointerventional procedures needs to be analyzed. We report the results of an open-label Phase I study to evaluate the safety of the use of eptifibatide during carotid angioplasty and stent placement.

METHODS

Each study patient received eptifibatide administered intravenously as a 135-microg/kg single-dose bolus, then a 0.5-microg/kg/min infusion for 20 to 24 hours during carotid angioplasty and stent placement. The primary efficacy end point was the 30-day composite occurrence of death, cerebral infarction, transient ischemic attack, and unplanned or urgent surgical intervention, thrombolysis, or subsequent percutaneous revascularization. The primary safety end point was bleeding. Bleeding complications were classified as major (hemoglobin decrease >5 g/dl), minor (hemoglobin decrease 3-5 g/dl), or insignificant.

RESULTS

Ten patients (mean age, 73 yr; four men) were treated by use of the study protocol. One patient developed a minor stroke postprocedurally (National Institutes of Health Stroke Scale score of 21 at 24 h that improved to 1 at 7 d). Three patients underwent scheduled coronary artery bypass graft surgery 4 to 12 days after undergoing carotid angioplasty and stent placement. At 1-month follow-up, no new ischemic events were observed. Major or minor bleeding was not observed in any patient. Insignificant bleeding was observed in two patients.

CONCLUSION

The use of eptifibatide as an adjunct to carotid angioplasty and stent placement seems to be safe. Further studies are required to analyze the effectiveness and role of eptifibatide in neurointerventional procedures.

Horner's syndrome after carotid artery stenting: case report

BACKGROUND

Angioplasty and stenting of various lesions of the carotid artery is gaining in popularity. Our knowledge of the efficacy and limitations of this promising technology is incomplete. Although Horner's syndrome and its variants have been described after traumatic, spontaneous, or surgical carotid dissection, it has not been reported after carotid artery stenting.

CASE DESCRIPTION

A 36-year-old woman presented with left neck and ear pain and a 3-year history of rushing noises in her left ear. Angiography demonstrated evidence of dissection of the left internal carotid artery at the skull base with a pseudoaneurysm. The pseudoaneurysm was treated with a 6-mm diameter self-expanding stent in a 4-mm diameter left internal carotid artery. A few hours later, she developed partial Horner's syndrome with a subtle ipsilateral ptosis and miosis without anhidrosis. Angiography performed on the next day did not demonstrate further dissection or aneurysm growth but did show distention of the artery wall because of the stent. She did not develop any further sequelae.

CONCLUSION

This case suggests that stretching of the artery wall may result in stretching of surrounding structures. The sympathetic fibers surrounding the internal carotid artery are clearly sensitive to this degree of stretch. Possible complications associated with stretch injury must be considered when choosing the stent diameter.

Intraarterial recombinant tissue plasminogen activator for ischemic stroke: an accelerating dosing regimen

OBJECTIVE

Urokinase has been conventionally used for intraarterial thrombolysis in acute ischemic stroke. Recently, due to the withdrawal of urokinase from the market, attention has been focused on recombinant tissue plasminogen activator (r-tPA) for intraarterial administration. Data is limited regarding the intraarterial dose, efficacy, and safety profile of this agent.

METHODS

We prospectively studied 8 consecutive patients with acute ischemic stroke who were referred for intraarterial lysis. Each patient was considered by the treating neurologist to be a poor candidate for intravenous therapy. We administered a maximum total dose of 40 mg of r-tPA intraarterially via superselective catheterization. Angiograms were obtained after each 10 mg of r-tPA, and responses were graded using modified Thrombolysis in Myocardial Infarction (TIMI) criteria for perfusion and degree of thrombus.

RESULTS

Initial National Institutes of Health Stroke Scale (NIHSS) scores ranged from 16 to 21. Intervals from presentation to treatment initiation ranged from 1 to 8 hours. After administration of r-tPA, neurological improvement (decrease in NIHSS score > or =2) was observed in 4 patients. Mean perfusion grade improved from a pretreatment score of 0 with increasing doses of r-tPA to 1.1 +/- 1.0 with 10 mg, 1.5 +/- 1.4 with 20 mg, 2.0 +/- 0.8 with 30 mg, and 2.7 +/- 1.0 with 40 mg. Mean thrombus degree decreased from a pretreatment score of 4 with increasing doses of r-tPA to 2.8 +/- 1.2 after 10 mg, 2.6 +/- 1.4 after 20 mg, 1.9 +/- 1.5 after 30 mg, and 1.4 +/- 1.5 after 40 mg. Asymptomatic intraparenchymal hemorrhage was observed on CT scan in 2 patients at 24 hours.

CONCLUSION

Our study suggests that intraarterial r-tPA in doses up to 40 mg is relatively safe. The dose appears to facilitate the recanalization process by lysis of local thrombus and improvement in distal flow.

Transradial approach for vertebral artery stenting: technical case report

OBJECTIVE

We report the technique of transradial vertebral artery stenting for two patients in whom severe supra-aortic ectasia prevented ready access to the right vertebral artery origin.

METHODS

An Allen test was performed to verify ulnar artery collateral flow in the hand. After the administration of local anesthesia, a 6-French sheath was introduced into the radial artery. To allay induced spasm, a mixture of heparin (5000 IU/ml), verapamil (2.5 mg), nitroglycerine (400 microg/ml, 0.25 ml), and lidocaine (2%, 1.0 ml) was infused through the introducer sheath. A microguidewire was positioned across the vertebral artery lesion, followed by placement of a balloon-expandable stent.

RESULTS

Postdeployment angiography revealed improved vertebrobasilar system flow. There were no complications related to the radial artery. The patients tolerated the procedure without difficulty and were immediately ambulatory.

CONCLUSION

This novel approach should be considered for endovascular procedures for which access to the vertebral artery origin via the femoral approach is limited.

Abciximab as an adjunct to high-risk carotid or vertebrobasilar angioplasty: preliminary experience

OBJECTIVE

Abciximab, a platelet glycoprotein IIb/IIIa receptor inhibitor, has been shown to reduce the risk of ischemic events associated with coronary intervention. However, its role in neurointerventional procedures needs to be defined. We prospectively evaluated our initial experience with the use of abciximab in a series of high-risk patients undergoing carotid, basilar, or vertebral artery angioplasty.

METHODS

Patients were given an intravenous abciximab bolus (0.25 mg/kg), followed by infusion (10 microg/min) for a period ranging from 12 to 24 hours, as an adjunct to angioplasty in 20 procedures (19 patients). These patients were considered to be at high risk for thromboembolic events because of recent ischemic symptoms and/or complex lesion morphology. Before, immediately after, and 24 hours after the procedure, each patient was evaluated by a neurologist for the presence of new neurological deficits. Any bleeding or other complications during hospitalization were also recorded. Bleeding was defined as major (hemoglobin decrease >5 g/dl), minor (hemoglobin decrease 3-5 g/dl), or insignificant.

RESULTS

Angioplasty was performed in the internal carotid artery (n = 13), vertebral artery (n = 4), or basilar artery (n = 2). Stents were placed across 13 lesions. In one patient, angioplasty could not be performed owing to technical difficulties; however, abciximab was administered because of extensive lesion manipulation. Intraprocedural heparin was given in 19 procedures (35-86 U/kg intravenously) and partially reversed in 6 procedures. Low-dose intra-arterial thrombolytic agents were administered in seven patients before the lesion was crossed. Two patients experienced transient neurological deficits either during (n = 1) or immediately after (n = 1) the procedure. Another patient had complete occlusion of the right vertebral artery after angioplasty with complete recanalization after 24 hours of abciximab infusion. Major or minor bleeding was not observed in any patient. Insignificant bleeding was observed in eight patients. Thrombocytopenia was observed in one patient who received concomitant administration of intravenous heparin and abciximab infusion.

CONCLUSION

We observed a low frequency of neurological events in high-risk patients undergoing angioplasty with or without stent placement. Abciximab seems to be a relatively safe adjunct for carotid or vertebrobasilar endovascular intervention either alone or in combination with low-dose thrombolytics. Partial reversal of intraprocedural heparin should be considered to reduce the risk of postprocedural bleeding.

Cervical carotid revascularization

The use of angioplasty and stent techniques for revascularization of the cervical carotid bifurcation has been limited. Carotid endarterectomy has been demonstrated to be safe and effective in two multicentered randomized trials. In patients who are considered at risk for excessive morbidity and mortality from open surgical revascularization, carotid endovascular revascularization provides a good alternative. This article outlines the indications, methods, complications and perioperative management of patients treated with balloon angioplasty and stent of the cervical carotid bifurcation.

Intracranial stent placement to trap an extruded coil during endovascular aneurysm treatment: technical note

OBJECTIVE

The development of low profile, navigable stents has expanded the range of intracranial neuroendovascular procedures. We report a unique case of endovascular stent placement to trap a partially extruded Guglielmi detachable coil (GDC) during treatment of an internal carotid artery (ICA) cavernous segment aneurysm.

METHODS

A 49-year-old woman presented for endovascular coiling of a left superior hypophyseal artery aneurysm. Previously, a contralateral mirror lesion had been treated by stent-assisted coiling. Heparin was administered to maintain an activated coagulation time of greater than 250 seconds, and a guide catheter was placed in the cervical ICA. A microcatheter was advanced into the aneurysm over a microguidewire. A GDC-10, 3-dimension, 6 x 20-mm coil was placed within the aneurysm, forming a stable basket. Three additional GDCs were placed with near-complete obliteration of the aneurysm. Attempted placement of a fifth coil caused partial prolapse of a previously placed coil into the cavernous ICA. We decided to place a stent rather than to snare the extruded coil because the extruded coil was integral to the aneurysm coil mass. A 3.5x8-mm balloon-expandable stent was placed across the aneurysm orifice, trapping the extruded coil between the stent and ICA.

RESULTS

Digital subtraction angiography documented patency of the ICA lumen. The patient remains neurologically intact and awaits 3-month follow-up cerebral angiography.

CONCLUSION

Trapping of an extruded intraaneurysmal coil via stent placement obviated the need for coil removal and avoided the risk of coil mass manipulation. The use of a stent to displace extruded coils and reconstitute a "normal" lumen is an excellent addition to our endovascular armamentarium.

Efficacy and current limitations of intravascular stents for intracranial internal carotid, vertebral, and basilar artery aneurysms

OBJECT

Results of previous in vitro and in vivo experimental studies have suggested that placement of a porous stent within the parent artery across the aneurysm neck may hemodynamically uncouple the aneurysm from the parent vessel, leading to thrombosis of the aneurysm. For complex wide-necked aneurysms, a stent may also aid packing of the aneurysm with Guglielmi detachable coils (GDCs) by acting as a rigid scaffold that prevents coil herniation into the parent vessel. Recently, improved stent system delivery technology has allowed access to the tortuous vascular segments of the intracranial system. The authors report here on the use of intracranial stents to treat aneurysms involving different segments of the internal carotid artery (ICA), the vertebral artery (VA), and the basilar artery (BA).

METHODS

Ten patients with intracranial aneurysms located at ICA segments (one petrous, two cavernous, and three paraclinoid aneurysms), the VA proximal to the posterior inferior cerebellar artery origin (one aneurysm), or the BA trunk (three aneurysms) were treated since January 1998. In eight patients, stent placement across the aneurysm neck was followed (immediately in four patients and at a separate procedure in the remaining four) by coil placement in the aneurysm, accomplished via a microcatheter through the stent mesh. In two patients, wide-necked aneurysms (one partially thrombosed BA trunk aneurysm and one paraclinoid segment aneurysm) were treated solely by stent placement; coil placement may follow later if necessary. No permanent periprocedural complications occurred and, at follow-up examination, no patient was found to have suffered symptoms referable to aneurysm growth or thromboembolic complications. Greater than 90% aneurysm occlusion was achieved in the eight patients treated by stent and coil placement as demonstrated on immediate postprocedural angiograms. Follow-up angiographic studies performed in six patients at least 3 months later (range 3-14 months) revealed only one incident of in-stent stenosis. In the four patients originally treated solely by stent placement, no evidence of aneurysm thrombosis was observed either immediately postprocedure or on follow-up angiographic studies performed 24 hours (two patients), 48 hours, and 3 months later, respectively.

CONCLUSIONS

A new generation of flexible stents can be used to treat complex aneurysms in difficult-to-access areas such as the proximal intracranial segments of the ICA, the VA, or the BA trunk. The stent allows tight coil packing even in the presence of a wide-necked, irregularly shaped aneurysm and may provide an endoluminal matrix for endothelial growth. Although convincing experimental evidence suggests that stent placement across the aneurysm neck may by itself promote intraluminal thrombosis, the role of this phenomenon in clinical practice may be limited at present by the high porosity of currently available stents.

Improved cerebral perfusion after stenting of a petrous carotid stenosis: technical case report

OBJECTIVE AND IMPORTANCE

Atherosclerotic occlusive disease of the intracranial vasculature is associated with increased risk of systemic vascular occlusive disease and stroke. Therapeutic options have included anticoagulation therapy, antiplatelet therapy, or, in a limited number of patients, extracranial-intracranial vascular bypass procedures. We report a patient who had improved cerebral perfusion with silent watershed zone infarctions after endovascular stenting of a severe petrous segment carotid stenosis.

CLINICAL PRESENTATION

A 73-year-old man with severe coronary artery disease and unstable angina was referred for treatment of a 90% right petrous carotid artery stenosis before coronary artery bypass grafting. A brain single-photon emission computed tomographic scan using 99mTc-bicisate revealed diminished perfusion throughout the right internal carotid artery territory, particularly in posterior watershed zones.

TECHNIQUE

The patient underwent transfemoral placement of a 7-French introducer sheath, followed by a 7-French guide catheter. Urokinase (225,000 U) was infused through a microcatheter placed proximal to the lesion. No changes were noted in lesion morphology after this infusion. A microguidewire was navigated across the lesion. Subsequent balloon angioplasty with a coronary artery balloon was performed twice, followed by placement of a 4- x 12-mm coronary stent.

CONCLUSION

Selective internal carotid artery angiography after stenting revealed markedly improved flow. A brain 99mTc-bicisate single-photon emission computed tomographic scan performed within 24 hours of stent placement, revealed significantly improved perfusion within the right internal carotid artery territory. Two perfusion voids suggestive of embolic stroke were noted; both were clinically silent. The patient had uncomplicated coronary artery bypass grafting 72 hours later. Five months postoperatively, he remains at home, living independently and with intact neurological function. Intracranial stenting for severe atherosclerotic stenosis is technically possible. However, its ultimate clinical role remains to be determined.

Angioplasty and stenting of basilar artery stenosis: technical case report

OBJECTIVE AND IMPORTANCE

Symptomatic basilar artery stenosis has a poor prognosis. Treatment options are limited. Surgical bypasses are technically demanding and of no proven benefit. Percutaneous angioplasty is associated with a significant complication rate, because of intraplaque dissection, restenosis secondary to vessel recoil, and embolic phenomena. A new generation of intravascular stents that are flexible enough to navigate the tortuosities of the vertebral artery may provide a new therapeutic approach. We report a case of basilar artery stenosis that was treated using stent-assisted angioplasty.

CLINICAL PRESENTATION

A 56-year-old woman experienced a vertebrobasilar ischemic stroke, from which she recovered. Magnetic resonance angiography revealed severe proximal basilar artery stenosis. Brain Neurolite-single-photon emission computed tomographic scans revealed significantly decreased perfusion of the brainstem. Endovascular intra-arterial pressure measurements revealed a 35-mm Hg gradient across the lesion.

INTERVENTION

The patient underwent uncomplicated angioplasty and stenting of the proximal basilar artery, with excellent angiographic results.

CONCLUSION

The availability of new flexible intravascular stents, allowing access to tortuous proximal intracranial vessels, provides a new therapeutic approach for patients with basilar artery stenosis. Long-term follow-up monitoring is required to assess the durability of this approach.

Successful intracranial thrombolysis for cerebral thromboembolic complications resulting from cardiovascular diagnostic and interventional procedures

We report successful local thrombolysis to treat intracranial ischemic complications of angioplasty with stenting of a high-grade carotid artery stenosis, angioplasty with thrombolysis of an occluded venous graft, and routine coronary angiography. Intracranial complications occurring during cardiovascular diagnostic or interventional procedures can be reversed with prompt management via rescue thrombolysis. These events should not be viewed as irreversible complications, and the opportunity for intracranial thrombolysis should be available wherever cardiovascular interventional procedures are performed. The ability to quickly recognize and remedy complications occurring during these procedures is another step in the continued advancement of neuroendovascular therapy.

Postoperative hypotension after carotid angioplasty and stenting: report of three cases

OBJECTIVE AND IMPORTANCE: Hemodynamic instability after carotid angioplasty and stenting is not well recognized. We report three patients who developed sustained hypotension in the postoperative period after successful carotid angioplasty and stent placement for internal carotid artery stenosis in the carotid sinus region. CLINICAL PRESENTATION: In two patients, hypotension was initially induced by inflation of the angioplasty balloon. The third patient developed hypotension after completion of the procedure. In all cases, the hypotension persisted for 18 to 33 hours after the procedure. During the postoperative period, two of these patients also developed sinus bradycardia, which, in one patient, was further complicated by a third-degree atrioventricular block. INTERVENTION: The hypotension was successfully treated by intravenous vasopressors or inotropic agents. No permanent neurological or cardiac sequelae were observed. CONCLUSION: Sustained hypotension with or without bradycardia may develop after carotid angioplasty and stent placement, presumably as a result of carotid sinus dysfunction. During the postoperative period, patients should be monitored in settings suited to expeditious management of cardiovascular emergencies.

Angioplasty and stenting for carotid artery stenosis: indications, techniques, results, and complications

Following the favorable results obtained in the treatment of coronary artery disease, combined angioplasty and stenting has been advocated for the treatment of carotid artery stenosis as well. Although widespread application of angioplasty and stenting for carotid artery disease is neither indicated nor recommended, it may be a viable alternative therapy for select patients who are high-risk patients for surgery. The results of early series have suggested that endoluminal revascularization in these high-risk patients can be performed with an acceptable degree of safety. Although the incidence of death and major stroke rates following angioplasty and stenting procedures compares favorably with surgery, results of more recent clinical series have suggested that the incidence of perioperative transient neurological events and minor strokes may be higher than suggested by earlier reports, especially in patients with recent neurological symptoms and "unstable" plaques. In this article, the authors review the current potential indications for and preliminary results of angioplasty and stenting and describe their procedural technique. In addition, potential applications of stenting to intracranial thromboocclusive carotid artery disease are reviewed.

Percutaneous transluminal angioplasty of intracranial artery stenosis: clinical results in 24 patients

Circumscribed stenotic lesions of the intracranial arteries can cause cerebral ischemia by hemodynamic and/or thromboembolic mechanisms. Anticoagulation therapy, antiplatelet therapy, and bypass surgery are treatment strategies that have no direct impact on the underlying lesion. This study summarizes the experience of a single institution at which percutaneous transluminal angioplasty (PTA) of intracranial atherosclerotic stenoses was performed.

The authors performed a retrospective analysis of 24 consecutive patients. Their medical histories (cardiovascular risk factors, current clinical signs and symptoms and their duration, previous stroke[s], and medical treatment) were evaluated together with findings from previous imaging studies. The site and degree of the stenoses to be treated (target lesion) were identified with the use of ultrasound and angiography studies. Additional vascular stenoses were noted. Percutaneous transluminal angioplasty was performed using single-lumen balloon microcatheters with appropriate diameters. The results of PTA were correlated with angiographic and ultrasound findings and the clinical outcome.

Significant cardiovascular risk factors and clinical signs and symptoms related to the target lesion that persisted despite medical treatment were identified in all patients except one. The duration of symptoms varied from several days to 8 months. Previous stroke had occurred in four patients. The degree of stenosis was classified as “high grade” in 10 patients and as “subtotal” in 14. The target lesion (stenosis) was located in the anterior circulation in eight patients (four in the internal carotid and four in the middle cerebral arteries). Stenoses of posterior circulation vessels were treated in 16 patients (nine vertebral, six basilar, and one posterior cerebral arteries). Recanalization was rated “complete” in 15 patients and sufficient in six patients. In three patients residual stenosis remained. Complications were encountered in seven patients: two asymptomatic dissections, one transient vessel occlusion, one vessel occlusion with subsequent stroke, and three ischemic lesions likely due to thromboembolism, two of which caused only transient neurological symptoms.

Percutaneous balloon dilation proved effective in the treatment of intracranial atherosclerotic stenosis. There are, however, potential complications and experience with this procedure is only limited. Long-term results need to be determined. The authors conclude from their preliminary results that PTA may be an alternative to bypass surgery and conservative management and may be considered for patients in whom ischemic neurological symptoms persist despite medical treatment.

Management of elevated intracranial pressure in patients with Cryptococcal meningitis

BACKGROUND

The most important predictor of early mortality in patients with HIV-associated cryptococcal meningitis is mental status at presentation; patients who present with altered mental status have up to 25% mortality. Historically, cerebrospinal fluid (CSF) diversion in HIV-negative patients with cryptococcal meningitis and signs of elevated intracranial pressure (ICP) has improved survival. In an effort to affect survival and morbidity rates in patients with HIV-associated cryptococcal meningitis, we have initiated aggressive management of elevated ICP in patients with focal neurologic deficits, mental obtundation, or both.

METHODS

We identified 10 patients with HIV-associated cryptococcal meningitis who presented with symptoms consistent with elevated ICP, including headache, mental obtundation, papilledema, and cranial nerve palsies. Elevated opening pressure was defined as > 20 cm CSF during lumbar puncture. In patients with elevated opening pressures who had focal neurologic deficits or mental status changes refractory to serial lumbar puncture, management consisted of immediate placement of lumbar drains for continuous drainage of CSF to maintain normal ICP (10 cm CSF). Patients with persistent elevations of spinal neuraxis pressure following lumbar drainage underwent placement of lumbar peritoneal shunts.

RESULTS

All patients returned to their baseline level of consciousness following normalization of ICP. Two patients were weaned from lumbar drainage. Eight patients eventually required placement of lumbar peritoneal shunts for persistently elevated ICP despite successful antifungal therapy. Follow-up ranged from 1 to 15 months. One shunt infection occurred, one lumbar peritoneal shunt was converted to a ventriculoperitoneal shunt, and one shunt was removed.

CONCLUSIONS

Elevated ICP in patients with HIV-associated cryptococcal meningitis is a significant source of morbidity and mortality. The use of lumbar drainage and selective placement of lumbar peritoneal shunts in the management of elevated ICP in patients with HIV-associated cryptococcal meningitis can ameliorate the sequelae of elevated ICP.

The neurovascular complications of cocaine

BACKGROUND

Cocaine use has been temporally associated with neurovascular complications, including the rupture of intracerebral aneurysms. The purpose of the current study was to determine the type of neurovascular complications associated with cocaine use in our patient population, the temporal relationship between cocaine use and their onset, and whether cocaine users with subarachnoid hemorrhage (SAH) presented with smaller aneurysms at an earlier age than a control group of noncocaine users with SAH.

METHODS

Thirty-three patients who presented to the Detroit Medical Center with neurovascular sequelae associated with cocaine use were identified. All patients were chronic cocaine users who related a history of recent use confirmed by a drug screen. Cocaine users with SAH were compared to a control group of 44 patients with SAH who presented without evidence of cocaine use.

RESULTS

Sixteen patients presented with SAH. Twelve patients subsequently underwent four-vessel cerebral arteriogram revealing 14 aneurysms; six patients presented with intracerebral hemorrhage (ICH) and seven patients with evidence of ischemic stroke. Eighteen (54.5%) patients noted onset of their symptoms while using cocaine, 87.9% noted onset within 6 hours of use. Delayed presentation occurred predominantly in patients who suffered ischemic strokes. The average age of patients who used cocaine and presented with SAH secondary to a ruptured intracerebral aneurysm was 32.8 years with an average aneurysm diameter of 4.9 mm versus an average age of 52.2 years with an average aneurysm diameter of approximately 11.0 mm in noncocaine users. Population differences were statistically significant at the p < 0.05 level. Mortality was 27.3% for patients who presented with neurovascular sequelae of their cocaine use, with 77.8% of deaths occurring in patients who presented with SAH.

CONCLUSIONS

Chronic cocaine use appears to predispose patients who harbor incidental neurovascular anomalies to present at an earlier point in their natural history than similar non-cocaine users.

Ultrasound abnormalities in term infants on ECMO

The charts and cranial ultrasounds of 29 infants treated with extracorporeal membrane oxygenation (ECMO) for respiratory insufficiency secondary to meconium aspiration syndrome, primary pulmonary hypertension, congenital diaphragmatic hernia and/or sepsis were examined to identify ultrasound abnormalities. Seventeen (58.6%) developed extra-axial fluid collections, only two of which were progressive. Ten (34.5%) developed evidence of intracranial hemorrhage (ICH): seven caudate, one each in the thalamus, parietal and occipital lobes. Eight (27.65%) of the neonates had seizures while on ECMO, 5 of whom had concurrent ICH.

The management of cerebral perfusion pressure and intracranial pressure after severe head injury

Neurosurgical intervention attempts to minimize secondary central nervous system injury after severe head injury through the evacuation of mass lesions with subsequent manipulation of cerebral perfusion pressure and intracranial pressure. The normal brain couples blood flow to metabolic demand through autoregulation of the cerebral vasculature. After severe head trauma and its attendant increase in intracranial pressure, marked alterations in cerebral blood flow and perfusion may occur. Currently, intervention is based on maintenance of coronary perfusion pressure and aggressive management of intracranial pressure. Both may be impacted by manipulation of ventilation, systemic blood pressure and volume status, administration of osmotic diuretics, and head elevation. Such therapy in the patient with severe head injury attempts to maintain coronary perfusion pressure and adequate oxygen delivery in a damaged central nervous system with altered hemodynamics and raised intracranial pressure.

Anticoagulant effects of protamine sulfate in a canine model

Protamine sulfate is considered a weak anticoagulant, yet little is known concerning the mechanism of this effect or its relation to prior heparin exposure. This investigation defined the influence of increasing doses of protamine, with and without prior heparin anticoagulation, on the activated clotting time (ACT), thrombin clotting time (TCT), prothrombin time (PT), partial thromboplastin time (PTT), fibrinogen level, platelet count, and platelet aggregation to ADP in dogs (n = 8). Four doses of intravenous protamine sulfate (1.5, 3.0, 6.0, and 15.0 mg/kg) were studied in each animal, with at least 5 days between individual studies. Four dogs received heparin, 150 IU/kg 10 min prior to protamine sulfate administration, and four dogs received protamine sulfate alone. Protamine sulfate caused anticoagulation, both in the presence and absence of heparin, with significant changes occurring in the ACT, PTT, platelet count, and platelet aggregation. Relevant changes did not occur in the TCT, PT, or fibrinogen levels. Platelet effects were capable of causing bleeding with standard or excess use of protamine sulfate, especially if platelet numbers were already decreased, as might occur in surgical procedures where thrombocytopenia commonly accompanies major blood loss and replacement. The ACT, reflecting both the coagulation cascade and platelet function, was the test most profoundly affected by protamine overdosage, and therefore may be misleading as a measure of protamine reversal of heparin. The TCT, which is sensitive to heparin anticoagulation but not protamine-induced anticoagulation, should be more accurate in differentiating inadequate heparin reversal from the effects of excess protamine.