Intra-arterial papaverine-induced seizures: case report and review of the literature

Pharmacovigilance of herbal medicines: Concerns and future prospects

ETHNOPHARMACOLOGICAL RELEVANCE

The use of herbal medicines for prophylaxis, prevention, and treatment of various ailments is rising throughout the world because they are thought to be safer than allopathic treatments, which they are. However, several investigations have documented the toxicity and adverse drug reactions (ADR) of certain formulations and botanicals if not consumed wisely.

AIM OF THE STUDY

The goal of the current study is to address herbal medication pharmacovigilance (PV) modeling and related considerations for improved patient safety. Also, focus is laid on the comprehensive and critical analysis of the current state of PV for herbal medications at the national and international levels.

MATERIALS AND METHODS

Targeted review also known as focused literature review methodology was utilized for exploring the data from various scientific platforms such as Science Direct, Wiley Online Library, Springer, PubMed, Google Scholar using "pharmacovigilance, herbal medicine, traditional medicine, ADR, under reporting, herb toxicity, herb interactions" as keywords along with standard literature pertaining to herbal medicines that is published by the WHO and other international and national organizations etc. The botanical names mentioned in the present article were authenticated using World Flora Online database.

RESULTS

The historical developments paving the way for PV in regulatory setup were also discussed, along with various criteria's for monitoring herbal medicine, ADR of herbs, phytoconstituents, and traditional medicines, herb-drug interactions, modes of reporting ADR, databases for reporting ADR's, provisions of PV in regulatory framework of different nations, challenges and way forward in PV are discussed in detail advocating a robust drug safety ecosystem for herbal medicines.

CONCLUSION

Despite recent efforts to encourage the reporting of suspected ADRs linked to herbal medicines, such as expanding the programme and adding community pharmacists and other healthcare professionals as recognized reporters, the number of herbal ADR reports received by the regulatory bodies remains comparatively low. Since users often do not seek professional advice or report if they have side effects, under-reporting, is anticipated to be significant for herbal medications. There are inadequate quality control methods, poor regulatory oversight considering herbs used in food and botanicals, and unregulated distribution channels. In addition, botanical identity, traceability of herbs, ecological concerns, over-the-counter (OTC) herbal medicines, patient-physicians barriers requires special focus by the regulatory bodies for improved global safety of herbal medicines.

Shared and distinct ultra-rare genetic risk for diverse epilepsies: A whole-exome sequencing study of 54,423 individuals across multiple genetic ancestries

Identifying genetic risk factors for highly heterogeneous disorders like epilepsy remains challenging. Here, we present the largest whole-exome sequencing study of epilepsy to date to investigate rare variants that confer risk for a spectrum of epilepsy syndromes. With an unprecedented sample size of >54,000 human exomes, composed of 20,979 deep-phenotyped patients with epilepsy and 33,444 controls, we replicate previous gene findings at exome-wide significance; using a hypothesis-free approach, we identify potential novel associations. Most discoveries are specific to a particular subtype of epilepsy, highlighting distinct genetic contributions to different epilepsies. Combining evidence from rare single nucleotide/short indel-, copy number-, and common variants, we find convergence of different genetic risk factors at the level of individual genes. Further comparing to other exome-sequencing studies, we implicate shared rare variant risk between epilepsy and other neurodevelopmental disorders. Our study also demonstrates the value of collaborative sequencing and deep-phenotyping efforts, which will continue to unravel the complex genetic architecture underlying the heterogeneity of epilepsy.

The Phosphodiesterase 10A Inhibitor PF-2545920 Enhances Hippocampal Excitability and Seizure Activity Involving the Upregulation of GluA1 and NR2A in Post-synaptic Densities

Phosphodiesterase regulates the homeostasis of cAMP and cGMP, which increase the strength of excitatory neural circuits and/or decrease inhibitory synaptic plasticity. Abnormally, synchronized synaptic transmission in the brain leads to seizures. A phosphodiesterase 10A (PDE10A) inhibitor PF-2545920 has recently attracted attention as a potential therapy for neurological and psychiatric disorders. We hypothesized that PF-2545920 plays an important role in status epilepticus (SE) and investigated the underlying mechanisms. PDE10A was primarily located in neurons, and PDE10A expression increased significantly in patients with temporal lobe epilepsy. PF-2545920 enhanced the hyperexcitability of pyramidal neurons in rat CA1, as measured by the frequency of action potentials and miniature excitatory post-synaptic current. GluA1 and NR2A expression also increased significantly in post-synaptic densities, with or without SE in rats treated with PF-2545920. The ratio of p-GluA1/GluA1 increased in the presence of PF-2545920 in groups with SE. Our results suggest that PF-2545920 facilitates seizure activity via the intracellular redistribution of GluA1 and NR2A in the hippocampus. The upregulation of p-GluA1 may play an important role in trafficking GluA1 to post-synaptic densities. The data suggest it would be detrimental to use the drug in seizure patients and might cause neuronal hyperexcitability in non-epileptic individuals.

Seizures and Epileptiform Patterns in SAH and Their Relation to Outcomes

In subarachnoid hemorrhage (SAH), seizures are frequent and occur at different time points, likely reflecting heterogeneous pathophysiology. Young patients, those with more severe SAH (by clot burden or presence of severe mental status changes at onset or focal neurologic deficits at any time), those with associated increased cortical irritation (by infarction or presence of underlying hematoma), and patients undergoing craniotomy are at higher risk. Advanced neurophysiologic monitoring allows for seizure burden quantification, identification of subclinical seizures, and interictal patterns as well as neurovascular complications that may have an independent impact on the outcome in this population. Practice regarding seizure prophylaxis varies widely; its institution is often guided by the risk-benefit ratio of seizures and medication side effects. Newer anticonvulsants seem to be equally effective and may have a more favorable profile. However, questions regarding the association of seizures and vasospasm, the therapeutic dosing, timing, and duration of antiepileptic treatment and the impact of seizures and antiepileptics on the outcome remain unanswered. In this review, we provide a broad overview of the work in this area and offer a diagnostic and therapeutic approach based on our own expert opinion.

Cerebral vasospasm

Cerebral vasospasm causes delayed ischemic neurologic deficits after aneurysmal subarachnoid hemorrhage. This is a well-established clinical entity with significant associated morbidity and mortality. The underlying patholphysiology is highly complex and poorly understood. Large-vessel vasospasm, autoregulatory dysfunction, inflammation, genetic predispositions, microcirculatory failure, and spreading cortical depolarization are aspects of delayed neurologic deterioration that have been described in the literature. This article presents a perspective on cerebral vasospasm, as guided by the literature to date, specifically examining the mechanism, diagnosis, and treatment of cerebral vasospasm.

Cerebral Vasospasm in Critically III Patients with Aneurysmal Subarachnoid Hemorrhage: Does the Evidence Support the Ever-Growing List of Potential Pharmacotherapy Interventions?

The occurrence of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) is a significant event resulting in decreased cerebral blood flow and oxygen delivery. Prevention and treatment of cerebral vasospasm is vital to avert neurological damage and reduced functional outcomes. A variety of pharmacotherapy interventions for the prevention and treatment of cerebral vasospasm have been evaluated. Unfortunately, very few large randomized trials exist to date, making it difficult to make clear recommendations regarding the efficacy and safety of most pharmacologic interventions. Considerable debate exists regarding the efficacy and safety of hypervolemia, hemodilution, and hypertension (triple-H therapy), and the implementation of each component varies substantially amongst institutions. There is a new focus on euvolemic-induced hypertension as a potentially preferred mechanism of hemodynamic augmentation. Nimodipine is the one pharmacologic intervention that has demonstrated favorable effects on patient outcomes and should be routinely administered unless contraindications are present. Intravenous nicardipine may offer an alternative to oral nimodipine. The addition of high-dose magnesium or statin therapy has shown promise, but results of ongoing large prospective studies are needed before they can be routinely recommended. Tirilazad and clazosentan offer new pharmacologic mechanisms, but clinical outcome results from prospective randomized studies have largely been unfavorable. Locally administered pharmacotherapy provides a targeted approach to the treatment of cerebral vasospasm. However, the paucity of data makes it challenging to determine the most appropriate therapy and implementation strategy. Further studies are needed for most pharmacologic therapies to determine whether meaningful efficacy exists.

Endovascular treatment of subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a common and devastating form of stroke. A large number of patients with aSAH develop angiographic or clinical vasospasm responsible for high morbidity and mortality. Rapid advances in the field of interventional neurology and the development of minimally invasive techniques have resulted in expansion of potential therapeutic applications. Treatment of aSAH has benefited from this rapid advance in the field of endovascular therapies. In the first section of the review, we discuss the therapeutic options and techniques for embolizations of intracranial aneurysms. In the second section, we discuss evolving endovascular treatment methods employed to intervene in delayed complications of cerebral vasospasm in patients with aSAH.

Transluminal balloon angioplasty for symptomatic distal vasospasm refractory to medical therapy in patients with aneurysmal subarachnoid hemorrhage

BACKGROUND

Cerebral vasospasm (VSP) is a major cause of morbidity and mortality associated with subarachnoid hemorrhage. The current endovascular paradigm for VSP refractory to medical therapy is to perform angioplasty for proximal vessel VSP and vasodilator infusion for distal vessel VSP.

OBJECTIVE

To report our experience with a large series of balloon angioplasty for distal VSP refractory to medical therapy in patients with aneurysmal subarachnoid hemorrhage.

METHODS

This was a retrospective series of 32 patients with subarachnoid hemorrhage and symptomatic VSP refractory to medical therapy who were treated with balloon angioplasty for distal vessel VSP. Immediate angiographic results, procedure-related complications, and clinical outcomes were assessed.

RESULTS

From September 2001 to January 2010, 32 patients with symptomatic VSP refractory to medical therapy underwent angioplasty for distal arterial VSP. There were 26 women (81.3%); patients were 29 to 67 years of age. A total of 175 vessels were angioplastied (95 proximal and 80 distal). The only complication was rupture of an incompletely clipped aneurysm that was treated by immediate coiling and did not result in any clinical worsening. Repeated treatment was needed for 6 arteries (6 of 80, 7.5%). There were no procedure-related symptomatic complications. Good outcomes (modified Rankin Scale score ≤ 2) were observed in 23 of 28 patients (82.1%) with follow-up.

CONCLUSION

Balloon angioplasty for distal VSP is safe and effective and decreases the need for repeated intraarterial treatments seen with infusion of vasodilator.

Statins and anti-inflammatory therapies for subarachnoid hemorrhage

OPINION STATEMENT

Aneurysmal subarachnoid hemorrhage (SAH) induces a potent inflammatory cascade that contributes to endothelial dysfunction, imbalance of vasoactive substances (excess endothelin, depletion of nitric oxide), and arterial vasospasm. This process results in delayed cerebral ischemia, a major cause of neurologic disability in those surviving the initial hemorrhage. The only therapy shown to be effective in improving neurologic outcomes after SAH is a calcium-channel antagonist, nimodipine (although it achieved this result without reducing vasospasm). A number of novel therapies have been explored to inhibit the development of vasospasm and reduce the burden of ischemia and cerebral infarction. Statins are promising candidates, as they block multiple aspects of the inflammatory pathway that contributes to ischemic brain injury. Early clinical trials have produced conflicting results, however, and the adoption of statins in clinical practice should await the results of larger, more definitive studies. Though endothelin-receptor antagonists showed promise in significantly reducing vasospasm in preliminary trials, their failure to improve clinical outcomes in phase 3 studies has been disappointing, highlighting the complex link between vasospasm and ischemia. Future directions in the quest to improve outcomes of patients with SAH may need to approach ischemia as a multifactorial process with inflammatory, vasoactive, and ionic/metabolic components.

High-dose intra-arterial nicardipine results in hypotension following vasospasm treatment in subarachnoid hemorrhage

BACKGROUND

Intra-arterial (IA) nicardipine is often used to treat cerebral vasospasm associated with subarachnoid hemorrhage (SAH). While hypotension has been noted to be a dose-limiting side effect of intravenous infusions, this has seldom been reported for IA administration.

METHODS

We reviewed a consecutive series of patients who received IA nicardipine for SAH-associated vasospasm. Nicardipine was titrated to angiographic response, with blood pressure and intracranial pressure monitoring. We analyzed data using Wilcoxon signed rank, Student's t-test, Spearman's correlation, and χ(2) statistics as appropriate. A P value <0.05 was considered significant.

RESULTS

Thirty patients underwent 50 procedures in which nicardipine was the sole chemical vasodilator (median dose, 15 mg). Median mean arterial pressures (MAP) decreased from 118 to 100 mmHg (P < 0.001), with an intra-operative low of 80 mmHg. Both intra-operative and post-operative decreases in MAP were directly related to nicardipine dose (r (s) = 0.352, P = 0.022 and r (s) = 0.308, P = 0.047, respectively). Hypotension (MAP < 70 mmHg) occurred in 22%, and 44% required initiation of or increases in vasopressor therapy. After the first treatment, 11 of 16 patients treated with vasodilator therapy alone, and 5 of 14 patients who underwent additional balloon angioplasty (68.8 vs. 35.7%, P = 0.141), required further endovascular treatments due to recurrent vasospasm on subsequent days.

CONCLUSIONS

Intra-arterial nicardipine is associated with significant intra-operative blood pressure lowering, an increased requirement for intra-operative vasopressor therapy, and a tendency toward re-treatment when used as initial monotherapy for vasospasm.

Cerebrovasospasm following endoscopic cerebrospinal fluid leak repair

Endoscopic repair of spinal fluid leaks is a commonly performed procedure with low morbidity. However, this is the first report of cerebrovasospasm, following endoscopic repair of a cerebrospinal fluid (CSF) leak. A 51-year-old woman underwent endoscopic repair of a spontaneous CSF leak. She subsequently developed symptomatic cerebrovasospasm on postoperative day 3. This was successfully treated with intraarterial verapamil infusion.

Evidence-based pharmacotherapy for cerebral vasospasm

INTRODUCTION

The vast amount of literature on the pharmaceutical treatment of cerebral vasospasm after aneurysmal subarachnoid hemorrhage remains daunting. Optimal treatment regimens for patients can be obscured by studies not statistically powered to draw evidenced-based conclusions.

METHODS

In this chapter, we reviewed the English literature using the National Library of Medicine for studies regarding pharmacotherapies for the treatment of cerebral vasospasm. These studies were then categorized according to the US Preventative Services Task Force ranking system for evidence based medicine and reviewed each pharmacotherapy for its efficacy in the treatment of cerebral vasospasm.

RESULTS

Nimodipine (Nimotop), HMG Co-A reductase inhibitor (statins) and enoxaparin (Lovenox) were the only drugs with level-1 evidence available for the treatment of vasospasm from aneurysmal subarachnoid hemorrhage as defined by the US Preventative Services Task Force.

CONCLUSION

As the understanding of the pathophysiological mechanisms of vasospasm after aneurysmal subarachnoid hemorrhage evolves in the basic science laboratory, novel medications are being trialed in humans. However, significantly more work must be carried out in this area before we have an effective medical treatment that can prevent or reverse the devastating events of cerebral vasospasm.

Adverse effects of topical papaverine on auditory nerve function

BACKGROUND

Papaverine hydrochloride is a direct-acting vasodilator used to manage vasospasm during various neurosurgical operations. Transient cranial nerve dysfunction has been described in a few cases with topical papaverine. This study supports previous reports and provides neurophysiological evidence of an adverse effect on the auditory nerve.

METHODS

We conducted a retrospective review of 70 consecutive microvascular decompression operations and studied those patients who received topical papaverine for vasospasm. Topical papaverine was used as a direct therapeutic action to manage vasospasm in a total of 11 patients. The timing of papaverine application and ongoing operative events was reviewed relative to changes in neurophysiological recordings. Brainstem auditory evoked potentials (BAEPs) were routinely used to monitor cochlear nerve function during these operations.

FINDINGS

A temporal relationship was found between topical papaverine and BAEP changes leading to complete waveform loss. The average temporal delay between papaverine and the onset of an adverse BAEP change was 5 min. In 10 of 11 patients, BAEP waves II/III-V completely disappeared within 2 to 25 min after papaverine. Eight of these 10 patients had complete loss of BAEP waveforms within 10 min. One patient showed no recovery of later waves and a delayed profound sensorineural hearing loss. The average recovery time of BAEP waveforms to pre-papaverine baseline values was 39 min.

CONCLUSIONS

Topical papaverine for the treatment of vasospasm was associated with the onset of a transient disturbance in neurophysiological function of the ascending auditory brainstem pathway. The complete disappearance of BAEP waveforms with a consistent temporal delay suggests a possible adverse effect on the proximal eighth nerve. Recommendations to avoid potential cranial nerve deficits from papaverine are provided.

The effect of intra-arterial papaverine on ECoG activity in the ketamine anesthetized rat

The opium alkaloid papaverine (PPV) causes vasodilatation of the cerebral arteries through direct action on smooth muscle that reduces the constriction of smooth muscle. Intra-arterial papaverine (IAP) has been used widely to increase the regional cerebral blood flow in order to reverse the cerebral vasospasm that occurs during endovascular procedures. IAP-induced seizures have been reported, although PPV has anticonvulsive effects. This study determined the effects of IAP on electrocorticography (ECoG) in the ketamine anesthetized rats. We used 24 Sprague-Dawley male rats weighing 200-250 g. The animals were divided randomly into four groups: three treatment groups (groups 1-3) and a control (group 4). Groups 1, 2, and 3 were given 1, 7, and 14 mg/kg IAP, respectively. The ECoG was compared across groups. Our results indicated that IAP did not cause seizures and that it decreased the frequency of ketamine-induced epileptiform activity in the 14 mg/kg group.

[Endovascular treatment of vasospasm following subarachnoid aneurysmal haemorrhage]

An endovascular treatment of vasospasm following a subarachnoid aneurysmal haemorrhage is to be implemented if the patient presents clinical or biological symptoms arguing for brain ischemia in conjunction with increased Doppler velocities despite well controlled systemic haemodynamic. Treatment might be either pharmacological or haemodynamic. Calcium and phosphodiesterase inhibitors can be administered. The former could also provide a neuroprotective effect as compared to the latter. In Europe, nimodipine is widely used whereas nicardipine and verapamil are the major molecules administered in North America where iv nimodipine is not FDA approved. Papaverine is less used nowadays because of its short duration of action and of the risk of aggravation of raised intracranial pressure. Balloon angioplasty has a long lasting effect but can be applied only to proximal spasm. Complications of its use are rare but life threatening. In some cases, both the pharmacological approach and the mechanical approach are used in combination.

Advances in vasospasm treatment and prevention

Outcome after aSAH depends on several factors, including the severity of the initial event, perioperative medical management, surgical variables, and the incidence of complications. Cerebral vasospasm (CV) is ure to consistently respond to treatment, emphasizing the need for further research into the underlying mechanisms of SAH-induced cerebrovascular dysfunction. To this end, our paper reviews the relevant literature on the main therapies employed for CV after aSAH and discusses possible avenues for future investigations. Current management of this condition consists of maximal medical therapy, including triple H regimen and oral administration of calcium antagonists, followed by endovascular balloon angioplasty and/or injection of vasodilatory agents for refractory cases. As the precise pathophysiology of CV is further elucidated, the development of promising investigational therapies will follow.

Neurointerventional treatment of vasospasm

OBJECTIVES

To review the historical development and current status of endovascular techniques used in the treatment of symptomatic vasospasm following aneurysmal subarachnoid hemorrhage.

METHODS

This article summarizes the relevant literature on neurointerventional therapy for vasospasm, namely instillation of intraarterial medication (papaverine, nicardipine, verapamil) and transluminal balloon angioplasty. The authors synthesize the available literature with their own experience using the various endovascular modalities to treat vasospasm at high volume cerebrovascular centers.

TECHNIQUE

Indications for the use of neurointerventional therapy as well as a summary of the technique for transluminal angioplasty to treat vasospasm as employed by the authors is described.

DISCUSSION

Neurointerventional treatment of vasospasm following aneurysmal hemorrhage has been proven to be a safe and successful technique for those patients suffering symptomatic vasospasm refractory to medical management. The techniques contunue to undergo refinement as endovascular technology advances. We currently favor the use of balloon angioplasty over intraarterial antispasmotics due to the increased durability and long-lasting effects of the former and lower risk profile.

Clinical review: Prevention and therapy of vasospasm in subarachnoid hemorrhage

Vasospasm is one of the leading causes of morbidity and mortality following aneurysmal subarachnoid hemorrhage (SAH). Radiographic vasospasm usually develops between 5 and 15 days after the initial hemorrhage, and is associated with clinically apparent delayed ischemic neurological deficits (DID) in one-third of patients. The pathophysiology of this reversible vasculopathy is not fully understood but appears to involve structural changes and biochemical alterations at the levels of the vascular endothelium and smooth muscle cells. Blood in the subarachnoid space is believed to trigger these changes. In addition, cerebral perfusion may be concurrently impaired by hypovolemia and impaired cerebral autoregulatory function. The combined effects of these processes can lead to reduction in cerebral blood flow so severe as to cause ischemia leading to infarction. Diagnosis is made by some combination of clinical, cerebral angiographic, and transcranial doppler ultrasonographic factors. Nimodipine, a calcium channel antagonist, is so far the only available therapy with proven benefit for reducing the impact of DID. Aggressive therapy combining hemodynamic augmentation, transluminal balloon angioplasty, and intra-arterial infusion of vasodilator drugs is, to varying degrees, usually implemented. A panoply of drugs, with different mechanisms of action, has been studied in SAH related vasospasm. Currently, the most promising are magnesium sulfate, 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors, nitric oxide donors and endothelin-1 antagonists. This paper reviews established and emerging therapies for vasospasm.

Vasospasm in aneurysmal subarachnoid hemorrhage: diagnosis, prevention, and management

Cerebral vasospasm is a major cause of morbidity and mortality associated with subarachnoid hemorrhage (SAH). Advances in neuroimaging and development of newer intraparenchymal monitoring devices have improved the prediction and diagnosis of cerebral vasospasm significantly. Recent experimental and clinical trials have increased the armamentarium of preventive and treatment strategies for cerebral vasospasm. Vasospasm refractory to medical therapy usually is treated endovascularly with percutaneous transluminal balloon angioplasty (PTA) for proximal vessel vasospasm and vasodilator infusion for distal vessel vasospasm. Although vasospasm usually does not recur after PTA, recurrence is frequent after vasodilator infusion. The development of newer microballoon catheters has led to improvements in treatment of not only proximal but also distal vessel vasospasm with balloon angioplasty. This article reports on current knowledge in the diagnosis, prediction, prevention, and management of cerebral vasospasm.

Endovascular Management of Cerebral Vasospasm

CEREBRAL VASOSPASM REMAINS a leading cause of death and disability in patients with ruptured cerebral aneurysms. The development of endovascular intervention in the past two decades has shown promising results in the treatment of vasospasm. Endovascular techniques that have been used in humans include intra-arterial infusion of vasorelaxants and direct mechanical dilation with transluminal balloon angioplasty. This article reviews the current indications and role of endovascular therapy in the management of cerebral vasospasm, its clinical significance, and potential future therapies.

Safety and technical efficacy of over-the-wire balloons for the treatment of subarachnoid hemorrhage–induced cerebral vasospasm

Object

Over the past decade, low-pressure, flow-directed balloons have been replaced by over-the-wire balloons in the treatment of vasospasm induced by subarachnoid hemorrhage (SAH). The authors assess the procedural safety and technical efficacy of these newer devices.

Methods

Seventy-five patients who underwent 85 balloon angioplasty procedures for the treatment of SAH-induced vasospasm were identified from a prospective quality-assurance database. Medical records and angiographic reports were reviewed for evidence of procedural complications and technical efficacy.

No vessel rupture or perforation occurred, but thromboembolic complications were noted in four (4.7%) of the 85 procedures. Balloon angioplasty was frequently attempted and successfully accomplished in the distal internal carotid (100%), proximal middle cerebral (94%), vertebral (73%), and basilar (88%) arteries. Severe narrowing was present in 89 proximal anterior cerebral arteries. Angioplasty was attempted in 41 of these vessels and was successful in only 14 (34%). In 19 of the 27 unsuccessful attempts, the balloon could not be advanced over the wire due to severe vasospasm or unfavorable vessel angle. Follow-up angiography in a subset of patients demonstrated that severe recurrent vasospasm occurred in 15 (13%) of 116 vessels studied after angioplasty.

Conclusions

Over-the-wire balloons involve a low risk for vessel rupture. The anterior cerebral artery remains difficult to access and successfully treat with current devices. Further improvements in balloon design, such as smaller inflated diameters and better tracking, are necessary. Finally, thromboembolic complications remain an important concern, and severe vasospasm may recur after balloon angioplasty.

Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage: An Overview of Pharmacologic Management

Cerebral vasospasm remains one of the leading causes of mortality in patients who experience a subarachnoid hemorrhage but survive the initial 24 hours. Vasospasm generally occurs 3-4 days after the initial subarachnoid hemorrhage and peaks at 5-7 days. The pathophysiology of vasospasm is poorly understood, which directly contributes to the inconsistency of management and creates a formidable challenge in clinical practice. Traditionally, hemodilution, hypervolemia, and induced hypertension (so-called triple H therapy); calcium channel blockers; and endovascular therapy have been used as either prophylactic therapy or treatment. However, management of vasospasm varies among physicians and institutions mainly because of a lack of large clinical trials and inconsistent results. Practice has been based primarily on case reports and the preference of each practitioner. Several experimental therapies have been explored; however, large, prospective, randomized controlled trials are needed to elucidate the role of these therapies.

Endovascular treatment of cerebral vasospasm: transluminal balloon angioplasty, intra-arterial papaverine, and intra-arterial nicardipine

Cerebral vasospasm is still one of the leading causes of morbidity and mortality from subarachnoid hemorrhage. Vasospasm refractory to medical management can be treated with endovascular therapies, such as transluminal balloon angioplasty or infusion of intra-arterial vasodilating agents. In our review of clinical series reported in the English language literature, transluminal balloon angioplasty produced clinical improvement in 62% of patients, significantly improved mean transcranial Doppler (TCD) velocities(P <.05), significantly improved cerebral blood flow (CBF) in 85% of patients as studied by (133)Xenon techniques and serial single photon emission computerized tomography,and was associated with 5.0% complications and 1.1% vessel rupture. Intra-arterial papaverine therapy produced clinical improvement in 43% of patients but only transiently,requiring multiple treatment sessions (1.7 treatments per patient); significantly improved mean TCD velocities (P <.01) but only for less than 48 hours; improved CBF in 60% of patients but only for less than 12 hours; and was associated with increases in intracranial pressure and 9.9% complications. Intra-arterial nicardipine therapy produced clinical improvement in 42% of patients, significantly improved mean TCD velocities (P <.001) for 4 days, and was associated with no complications in our small series. We have adopted a treatment protocol at our institution of transluminal balloon angioplasty and intra-arterial nicardipine therapy as the endovascular treatments for medically refractory cerebral vasospasm.

A 70-year-old woman with poor grade subarachnoid hemorrhage complicated by carotid stenosis, cerebral vasospasm, and cerebral rebleed

INTRODUCTION

Subarachnoid hemorrhage is one of the most common entities encountered in neurocritical care units. Knowledge of disease sequelae and their management is paramount for all neurointensivists.

MATERIALS AND METHODS

This study relates the case of a 70-year-old woman with poor grade subarachnoid hemorrhage who underwent endovascular detachable coil embolization of a right internal carotid artery aneurysm. Her hospital course was subsequently complicated by symptomatic carotid stenosis and cerebral vasospasm requiring intervention.

DISCUSSION

The discussants present their views regarding five main questions pertaining to management of the patient regarding the choice of endovascular versus surgical aneurysm occlusion, stent-supported angioplasty in a patient with a recent subarachnoid hemorrhage, and treatment options for vasospasm.

Therapeutic advances in interventional neurology

Rapid advances in the field of interventional neurology and the development of minimally invasive techniques have resulted in a great expansion of potential therapeutic applications. We discuss therapeutic interventional neurology as applied in clinical practice in one of the two possible ways: 1) embolization leading to occlusion of blood vessels; and 2) revascularization leading to reopening of blood vessels. These procedures can be applied to a broad range of cerebrovascular diseases. In the first section of this review, we will explore the evolution of these interventions to occlude aneurysms, arteriovenous malformations, neurovascular tumors, and injuries. In the second section, revascularization in acute ischemic stroke, stenosis, and dural venous thrombosis will be discussed.

Endovascular treatment of cerebral vasospasm following aneurysmal subarachnoid hemorrhage

Endovascular treatment by balloon angioplasty or intra-arterial papaverine infusion has been established as a valuable treatment option in patients with cerebral vasospasm refractory to maximal medical therapy. A summary of the indications, applications and limitations is provided for microcatheter guided selective papaverine infusion and transluminal balloon angioplasty in patients who sustain cerebral vasospasm following subarachnoid haemorrhage. Structured neuro-intensive and endovascular treatment of imminent vasospasm integrate papaverine administration and balloon angioplasty as complimentary rather than alternative techniques.

Neurotoxicity of Intra-arterial Papaverine Preserved with Chlorobutanol Used for the Treatment of Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Papaverine is used to vasodilate cerebral arteries undergoing vasospasm from subarachnoid hemorrhage. However, papaverine inhibits cellular respiration in vitro and could cause neurotoxicity in humans.

METHODS

We studied 5 consecutive patients with cerebral vasospasm who were treated with intra-arterial papaverine preserved with chlorobutanol and imaged with MRI fluid-attenuated inversion recovery and diffusion-weighted imaging after treatment. One patient had histological analysis of the brain at autopsy.

RESULTS

All 5 patients exhibited marked neurological decline immediately after treatment, and this was sustained through hospital discharge. In all cases, MRI images showed selective gray matter-only signal changes within the vascular territory treated with papaverine. Histological analysis of 1 case brought to autopsy showed selective injury to islands of neurons with relative sparing of white matter.

CONCLUSIONS

Intra-arterial delivery of papaverine preserved with chlorobutanol into vasospastic anterior cerebral arteries may result in marked neurological deterioration with selective gray matter changes on MRI imaging. This effect is consistent with a permanent toxic effect to human brain. It is unclear whether this toxicity is caused by papaverine or chlorobutanol, and its use in the treatment of cerebral vasospasm should be reserved for cases without alternatives.

Critical care issues in stroke and subarachnoid hemorrhage

The outcomes of devastating neurological emergencies such as stroke and subarachnoid hemorrhage may be measurably improved by timely treatment in a neurointensive care unit (NICU). Optimal care requires a multidisciplinary approach, with attention to a wide range of treatment issues. This review examines the key therapeutic concerns in the NICU management of acute ischemic and hemorrhagic stroke and subarachnoid hemorrhage, including mechanical ventilation, blood pressure management, cardiac monitoring, intracranial pressure assessment, vasospasm, seizures, sedation, fluids, electrolytes, and nutrition. The discussion of mechanical ventilation includes rapid sequence induction and intubation, indication for intubation and extubation, and prognostic factors in mechanical ventilation. Differing blood pressure management concerns in hemorrhagic and ischemic events are discussed, and specific target blood pressures and pharmacologic interventions are reviewed. The discussion of cardiac monitoring includes concurrent stroke and cardiac ischemia and arrhythmias, cardiac imaging, anticoagulation, and vasopressor therapy. The importance, monitoring and management of cerebral blood flow and intracranial pressure (ICP) are discussed, and strategies for treatment of elevated ICP are outlined in detail. The discussion of vasospasm includes evaluation, prophylaxis, and treatment with medications, hypervolemic hemodilution, and angioplasty. Management of seizure and status epilepticus in stroke and subarachnoid hemorrhage are reviewed and current algorithms are presented. The management of fluids, electrolytes and enteral nutrition are also reviewed.