Nicardipine pellets for the prevention of cerebral vasospasm

[Intracisternal administration of verapamil for the prevention and treatment of vasospasm in patients after microsurgical treatment of cerebral aneurysms in the acute period of hemorrhage]

The first results of intracisternal administration of verapamil for the prevention and treatment of cerebral vasospasm (CVS) in patients in the acute period of subarachnoid hemorrhage (SAH) after microsurgical clipping of cerebral aneurysms are presented.

OBJECTIVE

Safety assessment of the method of prolonged intracisternal infusion (PII) of verapamil.

MATERIAL AND METHODS

Over the period from May 2017 to December 2018, 42 patients were included in the study, who underwent clipping of aneurysm of the anterior segments of the Willis circle. Most patients (78.6%) were operated during the first 6 days after SAH. For each patient, a thin silicone catheter was installed, through which verapamil was infused. A prerequisite was the installation of external ventricular drainage and opening of the lamina terminalis. The daily dosage of verapamil varied from 25 to 50 mg of the drug diluted in 200-400 ml of isotonic sodium chloride solution. The indication for the use of the PII method was the presence of one of the following factors: a score on the Hunt-Hess scale from III to V, 3 or 4 points on the Fisher scale, confirmed angiographically by the CVS before the operation.

RESULTS

The PII procedure was performed from 2 to 5 days. The average dose of verapamil was 143.5±41.2 mg additionally, in the presence of an angiographically confirmed CVS accompanied by clinical manifestations, 14 (33.4%) patients received intra-arterial injection of verapamil in several stages, with individual selection of the drug dose. The formation of new cerebral ischemic foci of vasospastic genesis was observed in only 1 (2.4%) patient. No infectious intracranial complications were noted. The average follow-up period was 297.6±156.1 days. Long-term treatment outcomes, assessed by a modified Rankin scale from 0 to 2 points, were observed in 83.3% of patients. There were no outcomes such as vegetative status and no deaths. The frequency of liquorodynamic disorders, as well as epileptic syndrome did not exceed that among patients with SAH according to the literature.

CONCLUSION

The study has confirmed the safety of prolonged PII. The efficacy of the method, compared with other methods for CVS treatment requires further investigation. The first results look quite promising: the observation shows a low percentage of new foci of cerebral ischemia and the absence of deaths associated with it. In patients with severe CVS, the efficacy of the PII method is increased when combined with intra-arterial administration of verapamil.

An introduction to the pathophysiology of aneurysmal subarachnoid hemorrhage

Pathophysiological processes following subarachnoid hemorrhage (SAH) present survivors of the initial bleeding with a high risk of morbidity and mortality during the course of the disease. As angiographic vasospasm is strongly associated with delayed cerebral ischemia (DCI) and clinical outcome, clinical trials in the last few decades focused on prevention of these angiographic spasms. Despite all efforts, no new pharmacological agents have shown to improve patient outcome. As such, it has become clear that our understanding of the pathophysiology of SAH is incomplete and we need to reevaluate our concepts on the complex pathophysiological process following SAH. Angiographic vasospasm is probably important. However, a unifying theory for the pathophysiological changes following SAH has yet not been described. Some of these changes may be causally connected or present themselves as an epiphenomenon of an associated process. A causal connection between DCI and early brain injury (EBI) would mean that future therapies should address EBI more specifically. If the mechanisms following SAH display no causal pathophysiological connection but are rather evoked by the subarachnoid blood and its degradation production, multiple treatment strategies addressing the different pathophysiological mechanisms are required. The discrepancy between experimental and clinical SAH could be one reason for unsuccessful translational results.

Vasospasm in cerebral inflammation

All forms of cerebral inflammation as found in bacterial meningitis, cerebral malaria, brain injury, and subarachnoid haemorrhage have been associated with vasospasm of cerebral arteries and arterioles. Vasospasm has been associated with permanent neurological deficits and death in subarachnoid haemorrhage and bacterial meningitis. Increased levels of interleukin-1 may be involved in vasospasm through calcium dependent and independent activation of the myosin light chain kinase and release of the vasoconstrictor endothelin-1. Another key factor in the pathogenesis of cerebral arterial vasospasm may be the reduced bioavailability of the vasodilator nitric oxide. Therapeutic trials in vasospasm related to inflammation in subarachnoid haemorrhage in humans showed a reduction of vasospasm through calcium antagonists, endothelin receptor antagonists, statins, and plasminogen activators. Combination of therapeutic modalities addressing calcium dependent and independent vasospasm, the underlying inflammation, and depletion of nitric oxide simultaneously merit further study in all conditions with cerebral inflammation in double blind randomised placebo controlled trials. Auxiliary treatment with these agents may be able to reduce ischemic brain injury associated with neurological deficits and increased mortality.

Treatment of intracranial vasospasm following subarachnoid hemorrhage

Vasospasm has been a long known source of delayed morbidity and mortality in aneurysmal subarachnoid hemorrhage patients. Delayed ischemic neurologic deficits associated with vasospasm may account for as high as 50% of the deaths in patients who survive the initial period after aneurysm rupture and its treatment. The diagnosis and treatment of vasospasm has still been met with some controversy. It is clear that subarachnoid hemorrhage is best cared for in tertiary care centers with modern resources and access to cerebral angiography. Ultimately, a high degree of suspicion for vasospasm must be kept during ICU care, and any signs or symptoms must be investigated and treated immediately to avoid permanent stroke and neurologic deficit. Treatment for vasospasm can occur through both ICU intervention and endovascular administration of intra-arterial vasodilators and balloon angioplasty. The best outcomes are often attained when these methods are used in conjunction. The following article reviews the literature on cerebral vasospasm and its treatment and provides the authors’ approach to treatment of these patients.

Cerebral vasospasm pharmacological treatment: an update

Aneurysmal subarachnoid hemorrhage- (aSAH-) associated vasospasm constitutes a clinicopathological entity, in which reversible vasculopathy, impaired autoregulatory function, and hypovolemia take place, and lead to the reduction of cerebral perfusion and finally ischemia. Cerebral vasospasm begins most often on the third day after the ictal event and reaches the maximum on the 5th-7th postictal days. Several therapeutic modalities have been employed for preventing or reversing cerebral vasospasm. Triple "H" therapy, balloon and chemical angioplasty with superselective intra-arterial injection of vasodilators, administration of substances like magnesium sulfate, statins, fasudil hydrochloride, erythropoietin, endothelin-1 antagonists, nitric oxide progenitors, and sildenafil, are some of the therapeutic protocols, which are currently employed for managing patients with aSAH. Intense pathophysiological mechanism research has led to the identification of various mediators of cerebral vasospasm, such as endothelium-derived, vascular smooth muscle-derived, proinflammatory mediators, cytokines and adhesion molecules, stress-induced gene activation, and platelet-derived growth factors. Oral, intravenous, or intra-arterial administration of antagonists of these mediators has been suggested for treating patients suffering a-SAH vasospam. In our current study, we attempt to summate all the available pharmacological treatment modalities for managing vasospasm.

Calcium and potassium channels in experimental subarachnoid hemorrhage and transient global ischemia

Healthy cerebrovascular myocytes express members of several different ion channel families which regulate resting membrane potential, vascular diameter, and vascular tone and are involved in cerebral autoregulation. In animal models, in response to subarachnoid blood, a dynamic transition of ion channel expression and function is initiated, with acute and long-term effects differing from each other. Initial hypoperfusion after exposure of cerebral vessels to oxyhemoglobin correlates with a suppression of voltage-gated potassium channel activity, whereas delayed cerebral vasospasm involves changes in other potassium channel and voltage-gated calcium channels expression and function. Furthermore, expression patterns and function of ion channels appear to differ between main and small peripheral vessels, which may be key in understanding mechanisms behind subarachnoid hemorrhage-induced vasospasm. Here, changes in calcium and potassium channel expression and function in animal models of subarachnoid hemorrhage and transient global ischemia are systematically reviewed and their clinical significance discussed.

Novel treatments for vasospasm after subarachnoid hemorrhage

PURPOSE OF REVIEW

Cerebral vasospasm (CVS) after aneurysmal subarachnoid hemorrhage remains a considerable challenge in neurocritical care medicine. This review aims to cover the recent novel aspects and results in CVS treatment.

RECENT FINDINGS

On the basis of the recent literature, treatment focusing on CVS alone is outdated. A considerable amount of evidence suggests CVS not to be the sole cause of delayed cerebral ischemia (DCI) and poor outcome. Early brain injury, cortical spreading depolarization, inflammation and microthrombosis have recently been discussed as additional factors. The results of a well designed phase III trial, using an endothelin-1 antagonist, indicated a decrease in the occurrence of CVS but did not change the clinical outcome significantly. Induced hypertension is currently recommended for treating suspected DCI, whereas hemodilution and hypervolemia are not. Endovascular intervention is only recommended in case of refractory symptomatic CVS. A couple of newer treatment strategies are under evaluation. Phase III trials are underway for magnesium sulfate and statins. Clinical trials aiming specifically at recently discussed factors other than CVS have not been reported.

SUMMARY

Reviewing the recent literature, there have been some updates on recommendations and newer treatment modalities are under evaluation. However, a novel treatment with convincing evidence has not been reported so far.