Cerebral vasospasm: current understanding

Pharmacotherapy in SAH: Clinical Trial Lessons

Subarachnoid Haemorrhage (SAH) is a medical emergency with potentially devastating outcomes. It is without doubt that over the past decades, there has been a radical change in the approach towards patients with SAH, both in terms of the surgical as well as of the pharmacological treatments offered. The present review aims to outline the principal data regarding the best practice in the pharmacotherapy of SAH, as well as to sum up the emerging evidence from the latest clinical trials. To date, nimodipine is the only evidence-based treatment of vasospasm. However, extensive research is currently underway to identify novel substances with magnesium sulphate, cilostazol, clazosentan and fasudil, demonstrating promising results. Antifibrinolytic therapy could help reduce mortality, and anticoagulants, in spite of their associated hazards, could actually reduce the incidence of delayed cerebral ischemia. The effectiveness of triple-H therapy has been challenged, yet evidence on the optimal regimen is still pending. Statins may benefit some patients by reducing the incidence of vasospasm and delayed ischemic events. As several clinical trials are underway, it is expected that in the years to come, more therapeutic options will be added to the attending physician's armamentarium.

Effects of low-dose intravenous heparin therapy in aneurysmal subarachnoid hemorrhage: a randomized controlled clinical trial protocol

BACKGROUND

Heparin anticoagulation therapy is a widely used method to prevent cerebral vasospasm (CV) and venous thrombosis in patients with subarachnoid hemorrhage caused by ruptured cerebral aneurysms. Subcutaneous heparin injection is considered safe and effective, whereas continuous intravenous heparin infusion is still being debated due to the risk of bleeding. Although most retrospective studies have confirmed the safety and effectiveness of unfractionated heparin (UFH) after aneurysm embolization therapy and its ability to reduce CV, there is still no randomized clinical trial comparing UFH and subcutaneous low-molecular-weight heparin (LMWH) injection in this population. Therefore, this study aims to compare the clinical outcomes associated with these two treatment approaches.

METHODS

The study is an open-label, single-center, randomized controlled trial and aims to recruit 456 patients, with 228 patients in each group. The primary outcome was CV; the second outcomes measures are occurrence of bleeding events, ischemic events, heparin-induced thrombocytopenia, deep vein thrombosis, cerebral venous circulation time, brain edema score, and hydrocephalus incidence.

ETHICS AND DISSEMINATION

This study protocol obtained ethical approval from the Ethics Committee of Baoan People's Hospital, Shenzhen, Guangdong (approval number: BYL20220805). This work will be published in peer-reviewed international medical journals and presented at medical conferences.

TRIAL REGISTRATION

ClinicalTrials ID: NCT05696639. Registered on March 30, 2023.

Magnetic resonance analysis of deep cerebral venous vasospasm after subarachnoid hemorrhage in rabbits

Objective

Arterial spasm is proved to be an inducer of cerebral ischemia and cerebral infarction, while when a venous spasm occurs, cerebral edema is seen to be caused by a disturbance in cerebral blood flow. However, it is unclear and unproven whether venous spasm occurs after subarachnoid hemorrhage (SAH). To provide the theoretical basis for treating cerebral vasospasm after SAH, magnetic resonance imaging (MRI) was employed to observe the changes in the diameter of deep cerebral veins in rabbits after SAH.

Methods

Fourteen New Zealand rabbits were randomly divided into the SAH group (n = 10) and the normal saline group (NS group, n = 4). Specifically, the SAH models were established by the ultrasound-guided double injections of blood into cisterna magna. Moreover, the MRI was performed to observe the changes in the diameter of deep cerebral veins (internal cerebral vein, basilar vein, and great cerebral vein) and basilar artery before modeling (0 d) and 1, 3, 5, 7, 9, and 11 d after modeling.

Results

In the SAH group, the diameter of the basilar artery showed no evident change on the 1st d. However, it became narrower obviously on the 3rd d and 5th d, and the stenosis degree was more than 30%. The diameter gradually relieved from 7th to 9th d, and finally returned to normal on the 11th d. Moreover, the diameter of the internal cerebral vein significantly narrowed on the 1st d, the stenosis degree of which was 19%; the stenosis then relieved slightly on the 3rd d (13%), reached the peak (34%) on the 5th d, and gradually relieved from 7th d to 11th d. Moreover, the stenosis degree of the basilar vein was 18% on the 1st d, 24% on the 3rd d, and reached the peak (34%) on the 5th d.

Conclusion

After SAH in rabbits, the cerebral vasospasm was seen to occur in the basilar artery, and likewise, spasmodic changes took place in the deep cerebral vein. Furthermore, the time regularity of spasmodic changes between the cerebral vein and basilar artery was of significant difference, indicating that the venous vasospasm resulted in active contraction.

Cerebral Vasospasm-Left Heart Failure-Cerebral Infarction May Be a Potential Pathophysiological Mechanism of Malignant Cerebral Vasospasm

ABSTRACT

Cerebral vasospasm (CV) and delayed cerebral ischemia are serious complications after ruptured aneurysm with high mortality and disability rate. However, there are few reports of cardiogenic CV, the mechanism is unclear, and the treatment recommended by the guidelines is not detailed. This article describes in detail a 47-year-old woman with intracranial aneurysm rupture and hemorrhage. After interventional operation, left heart failure worsened CV and cerebral infarction. This article summarizes the diagnosis and treatment process of patients in detail, summarizes the treatment strategies of cardiogenic CV, and elaborates the pathological mechanism of CV-left heart failure-CV and cerebral infarction. Increase new understanding of the clinical diagnosis and treatment strategies of cardiogenic CV.

Sodium Variability and Probability of Vasospasm in Patients with Aneurysmal Subarachnoid Hemorrhage

OBJECTIVES

Vasospasm is a well-known complication of aneurysmal subarachnoid hemorrhage (aSAH) that generally occurs 4-14 days post-hemorrhage. Based on American Heart Association guidelines, the current understanding is that hyponatremic episodes may lead to vasospasm. Therefore, we sought to determine the association between repeated serum sodium levels of aSAH patients and its relationship to radiographic vasospasm.

MATERIALS AND METHODS

A single-center retrospective analysis from 2007-2016 was conducted of aSAH patients. Daily serum sodium levels were recorded up to day 14 post-admission. Hyponatremia was defined as a serum sodium value of < 135 mEq/L. We evaluated the relationship to radiologic vasospasm, neurologic deterioration, functional status at discharge, and mortality. A repeated measures analysis using a mixed-effect regression model was performed to assess the interindividual relationship between serum sodium trends and outcomes.

RESULTS

A total of 296 aSAH patients were included. There were no significant differences in interindividual serum sodium values over time and occurrence of radiographic vasospasm, neurologic deterioration, functional, or mortality outcomes (p = .59, p = .42, p = .94, p = .99, respectively) using the mixed-effect regression model. However, overall mean serum sodium levels were significantly higher in patients who had neurologic deterioration, poor functional outcome (mRS 3-6), and mortality.

CONCLUSIONS

Serum sodium level variations are not associated with subsequent development of cerebral vasospasm in aSAH patients. These findings indicate that serum sodium may not have an impact on vasospasm, and avoiding hypernatremia may provide a neurologic, functional and survival benefit.

Effects of Various Therapeutic Agents on Vasospasm and Functional Outcome After Aneurysmal Subarachnoid Hemorrhage-Results of a Network Meta-Analysis

BACKGROUND

Vasospasm and delayed ischemic neurologic deficits are the leading causes of morbidity and mortality after aneurysmal subarachnoid hemorrhage (aSAH). Several therapeutic agents have been assessed in randomized controlled trials for their efficacy in reducing the incidence of vasospasm and improving functional outcome. The aim of this network meta-analysis is to compare all these therapeutic agents for their effect on functional outcome and other parameters after aSAH.

METHODS

A comprehensive search of different databases was performed to retrieve randomized controlled trials describing the effect of various therapeutic approaches on functional outcome and other parameters after aSAH.

RESULTS

Ninety-two articles were selected for full text review and 57 articles were selected for the final analysis. Nicardipine prolonged-release implants were found to be the best treatment in terms of favorable outcome (odds ratio [OR], 8.55; 95% credible interval [CrI], 1.63-56.71), decreasing mortality (OR, 0.08; 95% CrI, 0-0.82), and preventing angiographic vasospasm (OR, 0.018; 95% CrI, 0.00057-0.16). Cilostazol was found to be the second-best treatment in improving favorable outcomes (OR, 3.58; 95% CrI, 1.97-6.57) and decreasing mortality (OR, 0.41; 95% CrI, 0.12-1.15). Fasudil (OR, 0.16; 95% CrI, 0.03-0.78) was found to be the best treatment in decreasing increased vessel velocity and enoxaparin (OR, 0.25; 95% CrI, 0.057-1.0) in preventing delayed ischemic neurologic deficits.

CONCLUSIONS

Our analysis showed that nicardipine prolonged-release implants and cilostazol were associated with the best chance of improving favorable outcome and mortality in patients with aSAH. However, larger multicentric studies from other parts of the world are required to confirm these findings.

Hybrid microcatheter angioplasty for refractory cerebral vasospasm

Cerebral vasospasm is a significant cause of morbidity and mortality associated with aneurysmal subarachnoid hemorrhage (aSAH). Intra-arterial chemical and mechanical angioplasty, performed alone or in combination, have been shown to ameliorate cerebral vasospasm and improve patient outcomes. Few options exist for patients who fail these traditional endovascular tactics. We propose a hybrid microcatheter technique that combines the mechanical benefit of transient high pressure induced by microcatheter fluid bolus with a low-dose vasodilator infusion. Five patients with moderate to severe symptomatic vasospasm who failed medical and traditional endovascular management were treated using a hybrid microcatheter technique. All angioplasty procedures were technically successful, and the degree of vasospasm improved following angioplasty. There were no complications related to the cerebral angioplasty procedures. None of the patients required repeat endovascular intervention. Hybrid microcatheter angioplasty may be a useful complement to mechanical or pharmacological techniques in the endovascular management of intractable cerebral vasospasm after aSAH.

Temporal Relationship between Hyponatremia and Development of Cerebral Vasospasm in Aneurysmal Subarachnoid Hemorrhage Patients: A Retrospective Observational Study

BACKGROUND

Hyponatremia is a common complication after aneurysmal subarachnoid hemorrhage (aSAH). Previous studies have reported an association between hyponatremia and vasospasm, however whether hyponatremia directly contributes to the pathogenesis of cerebral vasospasm (CVS), or is a by-product is still unclear. The aim of this study was to explore an association between hyponatremia and CVS after aSAH, and evaluating the temporality of these 2 events.

METHODS

A retrospective study of consecutive patients with aSAH admitted to the Baylor St. Luke's Medical center between January 2008 and December 2012 was conducted. Demographics, baseline characteristics, serum sodium levels, and evidence of vasospasm detected by transcranial Doppler, CT Angiogram, MR angiogram, and digital subtracted angiography were collected. Patients were dichotomized into a hyponatremic and a normonatremic group. CVS incidence and clinical outcome was compared between groups. Timing of CVS after initial hyponatremia episodes was recorded Results: One hundred and sixty 4 patients with aSAH were included. Hyponatremia was identified in 66 patients (40.2%) and CVS occurred in 71 subjects (43.2%). The incidence of CVS was higher in the hyponatremic group compared to the normonatremic group, 65.1 % versus 28.5%, respectively (P < .001). Hyponatremia preceded CVS by median 1.5 days suggesting a temporal trend.

CONCLUSIONS

Our study shows a significant association between hyponatremia and CVS, with hyponatremia preceding CVS events. This retrospective finding denotes the need for larger prospective studies, aiming to clarify the temporal relationship of serum sodium levels and CVS.

The Nimodipine-Sparing Effect of Perioperative Dexmedetomidine Infusion During Aneurysmal Subarachnoid Hemorrhage: A Prospective, Randomized, Controlled Trial

Background: Nimodipine can block the influx of calcium into the vascular smooth muscle cell and prevent secondary ischemia in patients with aneurysmal subarachnoid hemorrhage. However, the reduction of blood pressure after long-term intravenous administration of nimodipine has been associated with neurological deterioration. Yet, no effective solutions have been suggested to address this phenomenon. The use of neuroprotective drug combinations may reduce the risk of sudden blood pressure loss. This prospective, randomized, controlled trial was performed to evaluate the nimodipine-sparing effect of perioperative dexmedetomidine infusion during aneurysmal subarachnoid hemorrhage.

Methods: One hundred nine patients who underwent aneurysm embolization were divided into three groups: group C (n = 35, infused with 0.9% sodium chloride at the same rate as other two groups), group D1 (n = 38, dexmedetomidine infusion at 0.5 µg·kg^–1 for 10 min, then adjusted to 0.2 µg·kg^–1·h^–1), and group D2 (n = 36, dexmedetomidine infusion at 0.5 µg·kg^–1 for 10 min, then adjusted to 0.4 µg·kg^–1·h^–1). Patient-controlled analgesia was given for 48 h after surgery. The primary outcome measure was the total consumption of nimodipine during the first 48 h after surgery. The secondary outcome measures were recovery time at post-anesthesia care unit (PACU), postoperative pain intensity scores, dexmedetomidine and sufentanil consumption, hemodynamic, satisfaction of patients and neurosurgeon, neurologic examination (Glasgow Coma Scale, GCS), Bruggemann comfort scale, and adverse effects. Intraoperative hemodynamics were recorded at the following time-points: arrival at the operating room (T1); before intubation (T2); intubation (T3); 5 min (T4), 10 min (T5), and 15 min (T6) after intubation; suturing of femoral artery (T7); end of surgery (T8); extubation (T9); and 5 min (T10), 10 min (T11), and 15 min (T12) after arrival at the PACU. The level of sedation was recorded at 15 min, 30 min, 1 h, and 2 h after extubation. We also recorded the incidence of symptomatic cerebral vasospasm during 7 days after surgery, Glasgow Outcome Score (GOS) at 3 months, and incidence of cerebral infarction 30 days after surgery.

Results: The consumption of nimodipine during the first 48 h after surgery was significantly lower in group D2 (P < 0.05). Compared with group C, HR and MAP were significantly decreased from T2 to T12 in group D1 and D2 (P < 0.05). Patients in group D2 showed a significantly decreased MAP from T5 to T9 compared with group D1 (P < 0.05). The consumption of sevoflurane, remifentanil, dexmedetomidine, and nimodipine were all significantly reduced in groups D1 and D2 during surgery (P < 0.05). Compared with group C, MAP was significantly decreased in groups D1 and D2 during the first 48 h after surgery (P < 0.05). Compared with group C, consumption of sufentanil and dexmedetomidine at 1 h, pain intensity at 1 h, and 8 h after surgery were significantly decreased in groups D1 and D2 (P < 0.05). FAS was significantly higher in group D2 at 8 h, 16 h, and 24 h after surgery. LOS was significantly lower only in group D2 at 0.5 h after surgery (P < 0.05). Compared with group C, BCS was significantly higher group D2 at 4 h and 8 h after surgery (P < 0.05). There were no significant differences among the three groups in consumption of propofol, cisatracurium, fentanyl, and vasoactive drugs during operation, recovery time at PACU, satisfaction of patients and neurosurgeon, and number of applied urapidil and GCS during the first 48 h after surgery. The incidence of symptomatic cerebral vasospasm during 7 days after surgery, GOS of 3 months, and cerebral infarction after 30 days were also comparable among the three groups.

Conclusions: Dexmedetomidine (infusion at 0.5 µg·kg^–1 for 10 min, then adjusted to 0.4 µg·kg^–1·h^–1 during the surgery) significantly reduced the total consumption of nimodipine during the first 48 h after surgery and promoted early rehabilitation of patients although the incidences of symptomatic cerebral vasospasm, GOS, and cerebral infarction were not reduced.