Morphological changes in human cerebral arteries after percutaneous transluminal angioplasty for vasospasm caused by subarachnoid hemorrhage

Therapies for Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage

Delayed cerebral ischemia (DCI) is one of the most important complications of subarachnoid hemorrhage. Despite lack of prospective evidence, medical rescue interventions for DCI include hemodynamic augmentation using vasopressors or inotropes, with limited guidance on specific blood pressure and hemodynamic parameters. For DCI refractory to medical interventions, endovascular rescue therapies (ERTs), including intraarterial (IA) vasodilators and percutaneous transluminal balloon angioplasty, are the cornerstone of management. Although there are no randomized controlled trials assessing the efficacy of ERTs for DCI and their impact on subarachnoid hemorrhage outcomes, survey studies suggest that they are widely used in clinical practice with significant variability worldwide. IA vasodilators are first line ERTs, with better safety profiles and access to distal vasculature. The most commonly used IA vasodilators include calcium channel blockers, with milrinone gaining popularity in more recent publications. Balloon angioplasty achieves better vasodilation compared with IA vasodilators but is associated with higher risk of life-threatening vascular complications and is reserved for proximal severe refractory vasospasm. The existing literature on DCI rescue therapies is limited by small sample sizes, significant variability in patient populations, lack of standardized methodology, variable definitions of DCI, poorly reported outcomes, lack of long-term functional, cognitive, and patient-centered outcomes, and lack of control groups. Therefore, our current ability to interpret clinical results and make reliable recommendations regarding the use of rescue therapies is limited. This review summarizes existing literature on rescue therapies for DCI, provides practical guidance, and identifies future research needs.

Role of Transluminal Balloon Angioplasty for the Treatment of Vasospasm Due to Aneurysmal Subarachnoid Haemorrhage: A Multicentric Indian Experience

Background

Aneurysmal Subarachnoid Haemorrhage (aSAH) is a complex and critical neurological condition associated with significant mortality and morbidity. Apart from the initial insult due to the aneurysmal rupture itself, re-bleeding and severe cerebral vasospasm are some of the complications of aSAH that result in overall poor outcomes. Cerebral vasospasm in post-aSAH can result in delayed ischaemic neurological deficits. In the absence of timely interventions, it can lead to grave consequences for the patient. Management of cerebral vasospasm has been evolving over the years to prevent mortality and morbidity in aSAH patients.

Materials and methods

During 36 months from January 2018 to December 2020, 164 patients were admitted with aSAH in multiple Indian centres. Endovascular methods were used to treat all the aneurysms. Patients were observed for clinically symptomatic cerebral vasospasm. Patients with suspected vasospasm were further evaluated with a transcranial Doppler (TCD), brain computed tomography (CT) or magnetic resonance imaging (MRI) scan. In addition, digital subtraction angiography (DSA) of cerebral vessels was performed to evaluate vasospasm further. Twenty-two patients had clinically and angiographically significant vasospasm, and 20 patients were treated with transluminal balloon angioplasty (TBA).

Results

Satisfactory lumen dilation was achieved in 79 out of the 91 (86.81%) vasospastic segments, namely, distal internal carotid arteries (ICAs) 100%; middle cerebral arteries (MCA) 97.56% (M1=100%, M2=100%, M3=87.5%); vertebral arteries-100%; basilar arteries-100%; anterior cerebral arteries (ACA) 67.64% (A1=75%, A2=57.14%). The mean Modified Rankin Scale (mRS) score at 90 days was 0.75. 17 patients (85%) had an overall good outcome with no new neurological deficits. There were no cases of vessel rupture, dissection or thromboembolic complications.

Conclusion

TBA is a valuable, safe and effective option for managing clinically significant vasospasm caused by aSAH, adjuvant to medical management. 

The unexplained success of stentplasty vasospasm treatment : Insights using Mechanistic Mathematical Modeling

BACKGROUND

Cerebral vasospasm (CVS) following subarachnoid hemorrhage occurs in up to 70% of patients. Recently, stents have been used to successfully treat CVS. This implies that the force required to expand spastic vessels and resolve vasospasm is lower than previously thought.

OBJECTIVE

We develop a mechanistic model of the spastic arterial wall to provide insight into CVS and predict the forces required to treat it.

MATERIAL AND METHODS

The arterial wall is modelled as a cylindrical membrane using a constrained mixture theory that accounts for the mechanical roles of elastin, collagen and vascular smooth muscle cells (VSMC). We model the pressure diameter curve prior to CVS and predict how it changes following CVS. We propose a stretch-based damage criterion for VSMC and evaluate if several commercially available stents are able to resolve vasospasm.

RESULTS

The model predicts that dilatation of VSMCs beyond a threshold of mechanical failure is sufficient to resolve CVS without damage to the underlying extracellular matrix. Consistent with recent clinical observations, our model predicts that existing stents have the potential to provide sufficient outward force to successfully treat CVS and that success will be dependent on an appropriate match between stent and vessel.

CONCLUSION

Mathematical models of CVS can provide insights into biological mechanisms and explore treatment approaches. Improved understanding of the underlying mechanistic processes governing CVS and its mechanical treatment may assist in the development of dedicated stents.

Intra-Arterial Papaverine-Hydrochloride and Transluminal Balloon Angioplasty for Neurointerventional Management of Delayed-Onset Post-Aneurysmal Subarachnoid Hemorrhage Vasospasm

OBJECTIVE

After subarachnoid hemorrhage, delayed onset vasospasm can result in devastating ischemic stroke. The phenomenon of delayed cerebral ischemia (DCI) is not yet fully understood, and the correlation of angiographic vasospasm and cerebral infarction is still unclear. Therefore, we investigated the effect of endovascular treatment on the angiographic response and occurrence of DCI.

METHODS

Eighty patients with subarachnoid hemorrhage and serious cerebral vasospasm underwent endovascular treatment using intra-arterial papaverine-hydrochloride (IAP) or transluminal balloon angioplasty (TBA). The angiographic response and infarction rate were classified using the pre- and postinterventional angiographic images and computed tomography scans.

RESULTS

In 90% of patients, vasospasm could be improved. In most cases (78.8%), IAP was used. Retreatment after IAP was necessary in 32.9% of patients but never after TBA. A total of 233 vascular territories were treated in 128 procedures. Angiographic improvement was observed in 66.5% of territories, which was significantly associated with early intervention (P = 0.02), the use of TBA (P = 0.01), and the dose of papaverine-hydrochloride (P = 0.01). DCI occurred in 47.5% of the patients. Territorial infarction was associated with a poor Hunt and Hess grade (P = 0.03), day of aneurysm treatment (P = 0.01), severe vasospasm before (P = 0.02) and after (P = 0.03) treatment, and number of interventions (P = 0.01). However, the infarction rate was independent of the angiographic response.

CONCLUSION

The discrepancy of excellent angiographic results and the high incidence of DCI might stem from an inaccurate or a delayed diagnosis of impending ischemia. In view of the limited time window, optimized peri-interventional management and continuous cerebral multimodality neuromonitoring might be crucial for the ideal timing of endovascular procedures to prevent cerebral infarctions.

Complication rate of intraarterial treatment of severe cerebral vasospasm after subarachnoid hemorrhage with nimodipine and percutaneous transluminal balloon angioplasty: Worth the risk?

BACKGROUND AND PURPOSE

Delayed cerebral ischemia (DCI) is a complication of aneurysmal subarachnoid hemorrhage (SAH). Arterial cerebral vasospasm (CVS) is discussed as the main pathomechanism for DCI. Due to positive effects of per os nimodipine, intraarterial nimodipine application is used in patients with DCI. Further, percutaneous transluminal balloon angioplasty (PTA) is applied in focal high-grade spasm of intracranial arteries. However, clinical benefits of those techniques are unconfirmed in randomized trials so far, and complications might occur. We analyzed the occurrence of new infarcts in patients with severe CVS treated intra-arterially to assess benefits and risks of those techniques in a large single-center collective.

MATERIALS AND METHODS

All imaging and clinical data of 88 patients with CVS after SAH and 188 procedures of intraarterial nimodipine infusion and additional PTA in selected cases (18 patients, 20 PTA procedures) treated at our institution were reviewed. In the event of new infarcts after endovascular treatment of CVS, infarct patterns were analyzed to determine the most probable etiology.

RESULTS

Fifty-three percent of patients developed new cerebral infarction after intraarterial nimodipine and additional PTA in selected cases. Hereunder 47% were caused by persisting CVS. In 6% of patients, 3% of procedures respectively, new infarcts occurred due to complications of the intraarterial treatment including thromboembolism and arterial dissection. Of those, 3% of patients, 2% of procedures respectively, were assigned to thrombembolic complications of digital substraction angiography for intraarterial nimodipine. 17% of all patients treated with PTA (3/18=17%) showed infarction as a complication of PTA (15% of all PTA procedures). In 1% of patients, etiology of new infarction remained unclear.

CONCLUSION

Ischemic complications occur in about 6% of patients treated intraarterially for CVS, 3% of procedures respectively. Further, to date a benefit for patients treated with this therapy could not be proven. Therefore, intraarterial treatment of CVS should be performed only in carefully selected cases.

Association Between Neurological Outcomes Related to Aneurysmal Subarachnoid Hemorrhage and Onsite Access to Neurointerventional Radiology

OBJECTIVE

An onsite access to neurointerventional radiology (NIR) may be useful for managing patients with aneurysmal subarachnoid hemorrhage (aSAH) after the aneurysm-securing procedure. We aimed to assess the association between neurological outcomes related to aSAH and onsite access to NIR service.

METHODS

This was a sequential period study of 47 patients with aSAH admitted consecutively during the pre-NIR period (January 2010 to June 2012) compared with 81 patients with aSAH admitted consecutively during the post-NIR period (January 2013 to June 2015) at an academic tertiary referral intensive care unit (ICU). The primary end point was the incidence of poor neurological outcome, defined as modified Rankin scale of ≥3 at 6 months from ictus. Secondary outcomes included incidence of symptomatic vasospasm (SV) and length of stay in ICU/hospital.

RESULTS

The primary end point was observed in 18 of 47 (38%) patients during the pre-NIR period versus 25 of 81 (31%) patients during the post-NIR period (P = 0.39). The post-NIR period did not have an independent impact on neurological outcomes (adjusted odds ratio = 0.8, 95% confidence interval 0.3-2.1; P = 0.66). Of the patients who developed SV, 10 of 47 (21%) were during the pre-NIR period versus 33 of 81 (41%) during the post-NIR period (P = 0.02). The post-NIR period and higher Fisher grade were independent predictors of SV. Patients with SV had similar outcomes, but with longer stay in ICU during the post-NIR period compared with the pre-NIR period.

CONCLUSIONS

Among patients with aSAH, the post-NIR period was associated with more frequent detection of SV, more endovascular procedures, longer hospital stay, but with no appreciable improvement in neurological outcomes either overall or in the subset of patients with SV.

STUDY REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12616000201471.

Endovascular treatment for cerebral vasospasm following aneurysmal subarachnoid hemorrhage: predictors of outcome and retreatment

OBJECTIVE

Although endovascular therapy has been widely adopted for the treatment of cerebral vasospasm after aneurysmal subarachnoid hemorrhage (aSAH), its effect on clinical outcomes remains incompletely understood. The aims of this retrospective cohort study are to evaluate the outcomes of endovascular intervention for post-aSAH vasospasm and identify predictors of functional independence at discharge and repeat endovascular vasospasm treatment.

METHODS

We assessed the baseline and outcomes data for patients with aSAH who underwent endovascular vasospasm treatment at our institution, including intra-arterial (IA) vasodilator infusion and angioplasty. Statistical analyses were performed to determine factors associated with good outcome at discharge (modified Rankin Scale 0-2) and repeat endovascular vasospasm treatment.

RESULTS

The study cohort comprised 159 patients with a mean age of 52 years. Good outcome was achieved in 17% of patients at discharge (26/150 patients), with an in-hospital mortality rate of 22% (33/150 patients). In the multivariate analysis, age (OR 0.895; p=0.009) and positive smoking status (OR 0.206; p=0.040) were negative independent predictors of good outcome. Endovascular retreatment was performed in 34% (53/156 patients). In the multivariate analysis, older age (OR 0.950; p=0.004), symptomatic vasospasm (OR 0.441; p=0.046), initial treatment with angioplasty alone (OR 0.096; p=0.039), and initial treatment with combined IA vasodilator infusion and angioplasty (OR 0.342; p=0.026) were negative independent predictors of retreatment.

CONCLUSION

We found a modest rate of functional independence at discharge in patients with aSAH who underwent endovascular vasospasm treatment. Older patients and smokers had worse functional outcomes at discharge. Initial use of angioplasty appears to decrease the need for subsequent retreatment.

Precision medicine of aneurysmal subarachnoid hemorrhage, vasospasm and delayed cerebral ischemia

INTRODUCTION

Precision medicine provides individualized treatment of diseases through leveraging patient-to-patient variation. Aneurysmal subarachnoid hemorrhage carries tremendous morbidity and mortality with cerebral vasospasm and delayed cerebral ischemia proving devastating and unpredictable. Lack of treatment measures for these conditions could be improved through precision medicine. Areas covered: Discussed are the pathophysiology of CV and DCI, treatment guidelines, and evidence for precision medicine used for prediction and prevention of poor outcomes following aSAH. A PubMed search was performed using keywords cerebral vasospasm or delayed cerebral ischemia and either biomarkers, precision medicine, metabolomics, proteomics, or genomics. Over 200 peer-reviewed articles were evaluated. The studies presented cover biomarkers identified as predictive markers or therapeutic targets following aSAH. Expert commentary: The biomarkers reviewed here correlate with CV, DCI, and neurologic outcomes after aSAH. Though practical use in clinical management of aSAH is not well established, using these biomarkers as predictive tools or therapeutic targets demonstrates the potential of precision medicine.

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.

Institution of sustained endovascular treatment prior to clinical deterioration in patients with severe angiographic vasospasm: A retrospective observational study of clinico-radiological outcomes

Severe angiographic vasospasm (aVSP) is a risk factor for infarction following subarachnoid haemorrhage and infarction is strongly associated with poor outcome. We present the clinico-radiological results of cohort with severe aVSP who underwent a program of angiographic surveillance and sustained endovascular treatment using multiple verapamil infusions and/or transluminal balloon angioplasty (TBA).

METHODS

This was a dual-centre retrospective observational study. Angiographic screening for vasospasm was undertaken at days 5-7 post-ictus. Treatment was instituted principally on the basis of radiographic findings. The rate of infarction was evaluated on follow-up CT. Clinical outcome was assessed using the modified Rankin Scale (mRS).

RESULTS

Fifty-seven WFNS grades 1-5 patients were studied. The mean number of procedures/patient was 6, range 2-13. Mean verapamil dose administered to the ICA was 14 mg and VA was 12 mg. Thirty-one patients underwent TBA (52.6%). The rate of proximal vessel infarction was 3/45 (6.7%) for patients presenting <72 hours. Rates of favourable outcome (mRS 0-2) were 16/19 (84.2%) for WFNS grades 1-2, 12/19 (63.2%) for grades 3-4 and 5/19 (26.3%) for grade 5 patients. Delayed presentation >72 hours was the only factor on multivariate analysis to significantly predict aVSP-infarction [OR19.3 (3.2-116.6) P=0.0012]. Large aVSP-infarction [OR19.0 (1.7-216.4) 0.0179] and poor WFNS grade [OR 6.6 (1.3-33.9) P = 0.0233] were significant predictors of poor outcome on multivariate analysis.

CONCLUSION

This approach may result in low rates of aVSP-infarction and encouraging rates of favourable outcome when compared to literature benchmarks. Delayed presentation, however, predicts infarction and large infarct and poor initial grade significantly influence functional outcome.

Delayed progressive bilateral supraclinoid internal carotid artery stenosis in a patient with a ruptured basilar artery aneurysm

Cerebral vasospasm is a common radiographic and clinical diagnosis after subarachnoid hemorrhage. Conventional treatments include medical hypertension, hypervolemia, and modest hemodilution. When medical treatments fail in severe vasospasm cases, intra-arterial vasodilation and balloon angioplasty may be useful. We present a 47-year-old woman with a ruptured basilar artery aneurysm who developed severe bilateral internal carotid artery vasospasm requiring bilateral balloon angioplasty. Prior to discharge, the patient's bilateral stenosis had improved. Three months post-discharge, severe restenosis in her bilateral internal carotid arteries occurred; a rare event. Balloon angioplasty has been demonstrated to histologically tear and stretch collagen fibers in the vessel wall and overexpansion of vessels may lead to a neo-intimal reaction that is similar to the one seen after stent placement in the intracranial circulation. Clinicians should be aware of the possibility of delayed and progressive stenosis in vessels treated with angioplasty. Follow-up vascular imaging is necessary after subarachnoid hemorrhage. Future study is required on the treatment paradigms necessary for this delayed restenosis.

Balloons in endovascular neurosurgery: history and current applications

The use of balloons in the field of neurosurgery is currently an essential part of our clinical practice. The field has evolved over the last 40 years since Serbinenko used balloons to test the feasibility of occluding cervical vessels for intracranial pathologies. Since that time, indications have expanded to include sacrificing cervical and intracranial vessels with detachable balloons, supporting the coil mass in wide-necked aneurysms (balloon remodeling technique), and performing intracranial and cervical angioplasty for atherosclerotic disease, as well as an adjunct to treat arteriovenous malformations. With the rapid expansion of endovascular technologies, it appears that the indications and uses for balloons will continue to expand. In this article, we review the history of balloons, the initial applications, the types of balloons available, and the current applications available for endovascular neurosurgeons.

Current options for the management of aneurysmal subarachnoid hemorrhage-induced cerebral vasospasm: a comprehensive review of the literature

OBJECTIVES

Cerebral vasospasm is one of the leading causes of morbi-mortality following aneurysmal subarachnoid hemorrhage. The aim of this article is to discuss the current status of vasospasm therapy with emphasis on endovascular treatment.

METHODS

A comprehensive review of the literature obtained by a PubMed search. The most relevant articles related to medical, endovascular and alternative therapies were selected for discussion.

RESULTS

Current accepted medical options include the oral nimodipine and 'triple-H' therapy (hypertension, hypervolemia and hemodilution). Nimodipine remains the only modality proven to reduce the incidence of infarction. Although widely used, 'triple-H' therapy has not been demonstrated to significantly change overall outcome after cerebral vasospasm. Indeed, both induced hypervolemia and hemodilution may have deleterious effects, and more recent physiologic data favor normovolemia with induced hypertension or optimization of cardiac output. Endovascular options include percutaneous transluminal balloon angioplasty (PTA) and intra-arterial (IA) infusion of vasodilators. Multiple case reports and case series have been encountered in the literature using different drug regimens with diverse mechanisms of action. Compared with PTA, IA drug infusion has the advantages of distal penetration and a better safety profile. Its main disadvantages are the more frequent need for repeat treatments and its systemic hemodynamic repercussions. Alternative options using intraventricular/cisternal drug therapy and flow augmentation strategies have also shown possible benefits; however, their use is not yet as well established.

CONCLUSION

Blood pressure or cardiac output optimization should be the mainstay of hyperdynamic therapy. Endovascular treatment appears to have a positive impact on neurological outcome compared with the natural history of the disease. The role of intraventricular therapy and flow augmentation strategies in association with medical and endovascular treatment may, in the future, play a growing role in the management of patients with severe refractory vasospasm.

Endovascular treatment of medically refractory cerebral vasospasm following aneurysmal subarachnoid hemorrhage

BACKGROUND AND PURPOSE

CV following aneurysmal SAH is a significant cause of morbidity and mortality. We review our experiences using PTA and IA verapamil infusion for treating medically refractory cases.

MATERIALS AND METHODS

We performed a retrospective review of patients with SAH admitted from July 2003 to January 2008.

RESULTS

Of 546 patients admitted within 72 hours of symptom onset, 231 patients (42%) developed symptomatic CV and 189 patients (35%) required endovascular therapy. A total of 346 endovascular sessions were performed consisting of 1 single angioplasty, 286 IA verapamil infusions, and 59 combined treatments. PTA was performed on 151 vessel segments, and IA verapamil was infused in 720 vessel segments. IA verapamil doses ranged from 2.0 to 30.0 mg per vessel segment and from 3.0 to 55.0 mg per treatment session. Repeat treatments were necessary in 102 patients (54%) for persistent, recurrent, or worsening CV. There were 6 treatment-related complications, of which 2 resulted in clinical worsening. No deaths were attributable to endovascular therapy. At follow-up, 115 patients (61%) had a good outcome and 55 patients (29%) had a poor outcome. Sixteen patients died from causes related to SAH, while 3 died from other medical complications.

CONCLUSIONS

Endovascular treatments are an integral part of managing patients with medically refractory CV. In our experience, PTA and IA verapamil are safe, with a low complication rate, but further studies are required to determine appropriate patient selection and treatment efficacy.

Mechanical treatment of vasospasm

OBJECTIVE

Since cerebral vasospasm (CV) was first described nearly half a century ago, significant progress has been made in understanding its underlying pathophysiology and developing treatment modalities. The purpose of this review is to discuss the rationale behind mechanical interventions for CV as well as the efficacy and complications associated with these treatment options.

METHODS

The authors summarize the pertinent literature on the mechanical treatment of CV, focusing first on balloon angioplasty, second on therapy combined with intra-arterial drug infusion, and concluding by briefly discussing intra-aortic balloon counterpulsation. The epidemiology, pathophysiology, technique, outcome, timing and complications are discussed for each treatment option.

RESULTS

A review of the relevant medical literature reveals that in the last 20 years, endovascular techniques including transluminal balloon angioplasty, intra-arterial drug infusion and newer experimental strategies have provided an important supplement to the established medical therapy.

DISCUSSION

Despite these developments, however, CV remains a major contributor to poor outcome following aSAH and continued efforts are necessary to improve and refine endovascular strategies as well as develop new treatment modalities.

[Endovascular treatment of cerebral vasospasm due to aneurysmal subarachnoid hemorrhage]

Cerebral vasospasm remains a leading cause of death and disability in patients with aneurysmal subarachnoid hemorrhage. When vasospasm becomes refractory to maximal medical treatment, endovascular therapies may be considered as an option to increase cerebral blood flow to prevent cerebral infarction. Endovascular techniques include transluminal balloon angioplasty and intra-arterial infusion of vasorelaxants. This article reviews the various endovascular techniques for the treatment of cerebral vasospasm and discusses the mechanisms of action, techniques of administration, clinical results, and limitations of these treatment strategies.

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.

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.

Cerebrovascular Dynamics With Head-of-Bed Elevation in Patients With Mild or Moderate Vasospasm After Aneurysmal Subarachnoid Hemorrhage

• Background In patients with aneurysmal subarachnoid hemorrhage, elevation of the head of the bed during vasospasm has been limited in an attempt to minimize vasospasm or its sequelae or both. Consequently, some patients have remained on bed rest for weeks.

• Objectives To determine how elevations of the head of the bed of 20° and 45° affect cerebrovascular dynamics in adult patients with mild or moderate vasospasm after aneurysmal subarachnoid hemorrhage and to describe the response of mild or moderate vasospasm to head-of-bed elevations of 20° and 45° with respect to variables such as grade of subarachnoid hemorrhage and degree of vasospasm.

• Methods A within-patient repeated-measures design was used. The head of the bed was positioned in the sequence of 0°-20°-45°-0° in 20 patients with mild or moderate vasospasm between days 3 and 14 after aneurysmal subarachnoid hemorrhage. Continuous transcranial Doppler recordings were obtained for 2 to 5 minutes after allowing approximately 2 minutes for stabilization in each position.

• ResultsNo patterns or trends indicated that having the head of the bed elevated increases vasospasm. As a group, there were no significant differences within patients at the different positions of the head of the bed. Utilizing repeated-measures analysis of variance, P values ranged from .34 to .97, well beyond .05. No neurological deterioration occurred.

• Conclusions In general, elevation of the head of the bed did not cause harmful changes in cerebral blood flow related to vasospasm.

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.

The long-term effects of transluminal balloon angioplasty for vasospasms after subarachnoid hemorrhage: analyses of cerebral blood flow and reactivity

BACKGROUND

Transluminal balloon angioplasty (TBA) has come into wide use for management of symptomatic cerebral vasospasm after subarachnoid hemorrhage (SAH). The long-term effects of TBA in this clinical context on cerebral blood flow (CBF) and the functional properties of the arterial wall after aneurysmal SAH remain controversial. We therefore studied these effects.

METHODS

All patients underwent unilateral TBA. Xenon-enhanced computed tomography was performed for an average of 18 days after TBA to measure CBF and cerebrovascular reactivity (CVR). Cerebral blood flow and CVR were compared between the side of TBA and the contralateral side.

RESULTS

Nineteen vascular territories were treated successfully with TBA in 12 patients. Angiographic improvement of vasospasm was demonstrated in all 12 patients, and 9 (75%) patients showed neurological improvement. After balloon angioplasty, global CBF was 35.1 +/- 8.2 mL/100 g per minute, with CBF on the side with TBA (37.8 +/- 10.3 mL/100 g per minute) being essentially the same as that on the other side (P = .0671, paired Student t test). Likewise, reactivity to acetazolamide did not differ significantly between sides (P = .0817).

CONCLUSION

Transluminal balloon angioplasty increased proximal vessel diameters but showed no significant influence on CBF or vascular reactivity 3 weeks later. Benefits presumably were short term, but the procedure was clinically safe.

Signaling mechanisms in cerebral vasospasm

The elusive nature of events that sustain cerebral vasospasm after subarachnoid hemorrhage resulting from a ruptured aneurysm presents major challenges in designing effective therapies for this frequently devastating condition. Protracted cerebral artery constriction entails several dynamic components in intracellular signaling events initiated by endothelial factors, products of hemolysate, and numerous kinases, as well as increased intracellular Ca(2+). The rationale for potential treatment modalities and their efficacy are discussed in this brief review.

Inhibition of experimental vasospasm by pretreatment with ultraviolet light irradiation in a rat femoral artery model

OBJECTIVE

Chronic cerebral vasospasm is resistant to conventional treatments despite recent advances in treatment modalities. We studied the preventive effect of ultraviolet (UV) irradiation on development of vasospasm and its mechanism in a rat femoral artery model.

METHODS

The rat femoral artery model for vasospasm was used in this investigation (n = 108). The femoral arteries were divided into four groups: empty and no irradiation (control), UV irradiation (UV group), blood placement (VS group), and blood placement after UV irradiation (VS + UV group). Luminal area was measured, and smooth muscle cell counts in the medial layer of the vessel wall were obtained. An immunohistochemical study was performed with cross sections of fixed femoral arteries at 12 hours and 1, 3, 5, 7, and 49 days after blood placement. The rings of femoral arteries on Day 7 were subjected to pharmacological study.

RESULTS

Pretreatment with UV irradiation (VS + UV group) resulted not only in significant inhibition of chronic vasospasm but also in a significant decrease in smooth muscle cells compared with the VS group on Days 5 and 7. The UV-treated arteries (UV and VS + UV groups) exhibited a significant number of Bax- and Bcl-2-positive cells on Days 5 and 7, but few CPP-32 positive cells were observed at the same time points. In the pharmacological study, contractile response to KCI or phenylephrine was reduced significantly in the UV-treated arteries.

CONCLUSION

These results imply that UV irradiation prevents chronic vasospasm and suggest that UV-induced cell death plays an important role in the preventive effect without causing complications during the chronic period.

Pretreatment with continuous-wave ultraviolet irradiation to prevent the development of delayed vasospasm in the rabbit common carotid artery model

OBJECT

Ultraviolet (UV) light irradiation can lead to immunomodulation. The purpose of this study was to determine the preventive effect of UV light on cerebral vasospasm by using a rabbit common carotid artery (CCA) model.

METHODS

Rabbit CCAs were constricted for a long period by application of autologous blood within a silicon sheath. Before immersion in blood, the CCAs were adventitiously exposed to UV light emitted from a helium-cadmium laser (wavelength 325 nm) yielding an irradiation energy of 10 mJ/mm2. The occurrence of vasospasm was evaluated using angiography 48 hours after blood exposure in this model. The UV light treatment significantly reduced the degree of vasospasm. Compared with luminal diameters measured on Day 0, prior to treatment, the luminal diameters of UV light-treated arteries (six animals) decreased by only 6%, whereas that of the sham-treated arteries (eight animals) significantly decreased by 26% (p<0.001). Histological examination of UV light-treated CCAs revealed no endothelial damage and extended smooth-muscle cells, in which some fragmented nuclei were confirmed by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling. Twenty-eight days after blood exposure, examination of UV light-treated CCAs revealed only myointimal proliferation, similar to that of the sham-treated CCAs.

CONCLUSIONS

These results are the first to provide evidence of a prophylactic effect of UV light on vasospasm and are suggestive of involvement of apoptosis in the mechanism of this effect.

Efficacy of transluminal angioplasty for the management of symptomatic cerebral vasospasm following aneurysmal subarachnoid hemorrhage

OBJECT

Transluminal angioplasty has become a widely used adjunct therapy to medical management of symptomatic cerebral vasospasm following subarachnoid hemorrhage (SAH). Despite anecdotal reports of universal, angiographically confirmed reversal of vasospasm and high rates of clinical improvement, no rigorous examination of the efficacy of this procedure has been conducted. In this study the authors assess the efficacy of the aforementioned procedure.

METHODS

Thirty-eight patients enrolled as part of the North American trial of tirilazad in aneurysmal SAH underwent transluminal angioplasty for symptomatic cerebral vasospasm. Fifty-three percent of these patients showed good recovery or moderate disability based on their 3-month Glasgow Outcome Scale score. Among the 38 patients who underwent angioplasty, the severity and type of vasospasm, use of papaverine in addition to balloon angioplasty, timing of treatment, and dose of study drug did not have an effect on the outcome. The results of their neurological examinations improved in only four of the 38 patients immediately after the procedure. A conditional logistic regression analysis was performed in which these patients were compared with individuals matched for age, sex, dose of study drug, admission neurological grade, and modified Glasgow Coma Scale score at the time of angioplasty. No effect on favorable outcomes was found for this procedure.

CONCLUSIONS

Transluminal cerebral angioplasty is very effective in reversing angiographically confirmed vasospasm, and anecdotal reports of its clinical utility are numerous. However, in this report the authors conclude that its superiority to medical management for symptomatic cerebral vasospasm is questionable.

Long-term effects of in vivo angioplasty in normal and vasospastic canine carotid arteries: pharmacological and morphological analyses

OBJECT

A canine model of hemorrhagic vasospasm of the high cervical internal carotid artery (ICA) was used to study the long-term effects of transluminal balloon angioplasty (TBA) on the structure and function of the arterial wall.

METHODS

Forty dogs underwent surgical exposure of both distal cervical ICAs, followed by baseline angiographic studies on Day 0. Dogs in Group A (20 animals) underwent simple exposure of one ICA and placement of a silicone elastomer cuff around a segment of the opposite artery. These animals underwent repeated angiography on Day 7, and then TBA was performed on the uncuffed ICA; the cuff was removed from the opposite vessel. For dogs in Group B (20 animals), blood clot-filled cuffs were placed around both ICAs, and on Day 7 angiography was repeated and TBA was performed on one randomly selected ICA. Four animals were then killed from each group, and in the remaining animals the cuffs were removed from both ICAs. On Days 14, 21, 28, and 56, four animals from each group underwent repeated angiography and were then killed to permit pharmacological and morphological analyses of the ICAs. This protocol yielded five study categories: cuffed nonblood-coated arteries not subjected to TBA, blood-coated arteries not subjected to TBA, blood-coated arteries subjected to TBA, normal arteries subjected to TBA, and control arteries obtained from the proximal ICA in each animal. The contractile responses of isolated arterial rings obtained from each ICA were recorded after treatment with potassium chloride, noradrenaline, and serotonin, whereas relaxations in response to the calcium ionophore A23187 and papaverine were recorded after tonic contraction to noradrenaline had been established. Morphological analysis was performed using scanning electron microscopy. Arteries surrounded by an empty cuff exhibited no angiographic, pharmacological, or morphological differences compared with normal arteries on any study day. Arteries surrounded by blood developed angiographically confirmed vasospasm on Day 7, with characteristic pharmacological and morphological features; resolution of these symptoms occurred by Day 21. Vasospastic arteries subjected to TBA on Day 7 remained dilated on angiographic studies, exhibited impaired responses to pharmacological agents (except for papaverine), and showed altered morphological features until Day 28. Normal arteries subjected to TBA on Day 7 remained dilated on angiographic studies, exhibited impaired responses to pharmacological agents (except for papaverine), and displayed altered morphological features until Day 14.

CONCLUSIONS

These results indicate that the canine high cervical ICA model produces consistent and reproducible vasospasm that follows a similar time course to that seen in humans. When TBA is performed in vasospastic arteries, it results in an immediate functional impairment of vascular smooth muscle that lasts for 2 weeks, with resolution at 3 weeks; morphological changes are mostly resolved 3 weeks post-TBA. In normal vessels, TBA causes functional impairment and morphological alterations that are not as severe or as long-lasting as those seen in vasospastic arteries.

Morphological changes after percutaneous transluminal angioplasty

BACKGROUND

Percutaneous transluminal angioplasty (PTA) dilates constricted arteries at the circle of Willis to reverse cerebral ischemia caused by cerebral vasospasm. Although 90% of the patients show angiographic improvement after PTA, only 70% show clinical improvement. Why some patients do not improve after PTA is unknown. We report on a 48-year-old woman who failed to improve after PTA and died from aneurysm rerupture. Pathologic studies were performed to determine why PTA failed to reverse the symptoms of cerebral ischemia.

METHODS

The arteries of the brain were studied by light microscopy using Gomori's trichrome stain. The arteries were also studied by scanning and transmission electron microscopy.

RESULTS

The arteries that were dilated with PTA showed compression of the connective tissue, stretching of the internal elastic lamina, and a combination of compression and stretching of the smooth muscle. The small arteries and arterioles that had been treated with an infusion of intraarterial papaverine were constricted with a thickened intimal layer.

CONCLUSION

The persistence of cerebral vasospasm in small and perforating arteries may contribute to the failure of cerebral ischemia to reverse after PTA.

Comparison of balloon angioplasty and papaverine infusion for the treatment of vasospasm following aneurysmal subarachnoid hemorrhage

OBJECT

The purpose of this study was to test the hypothesis that balloon angioplasty is superior to papaverine infusion for the treatment of proximal anterior circulation arterial vasospasm following subarachnoid hemorrhage (SAH). Between 1989 and 1995, 125 vasospastic distal internal carotid artery or proximal middle cerebral artery vessel segments were treated in 52 patients.

METHODS

Blood flow velocities of the involved vessels were assessed by using transcranial Doppler (TCD) monitoring in relation to the day of treatment with balloon angioplasty or papaverine infusion. Balloon angioplasty and papaverine infusion cohorts were compared based on mean pre- and posttreatment velocity at 24 and 48 hours using the one-tailed, paired-samples t-test. Balloon angioplasty alone was performed in 101 vessel segments (81%) in 39 patients (75%), whereas papaverine infusion alone was used in 24 vessel segments (19%) in 13 patients (25%). Although repeated treatment after balloon angioplasty was needed in only one vessel segment, repeated treatment following papaverine infusion was required in 10 vessel segments (42%) in six patients because of recurrent vasospasm (p < 0.001). Seven vessel segments (29%) with recurrent spasm following papaverine infusion were treated with balloon angioplasty. Although vessel segments treated with papaverine demonstrated a 20% mean decrease in blood flow velocity (p < 0.009) on posttreatment Day 1, velocities were not significantly lower than pretreatment levels by posttreatment Day 2 (p = 0.133). Balloon angioplasty resulted in a 45% mean decrease in velocity to a normal level following treatment (p < 0.001), a decrease that was sustained.

CONCLUSIONS

Balloon angioplasty is superior to papaverine infusion for the permanent treatment of proximal anterior circulation vasospasm following aneurysmal SAH.