Beta Blockade and Clinical Outcomes in Aneurysmal Subarachnoid Hemorrhage

Association of pre-admission antihypertensive agents and outcomes in aneurysmal subarachnoid hemorrhage

BACKGROUND

Delayed cerebral ischemia (DCI) and poor functional outcome are common complications in patients who suffer from aneurysmal subarachnoid hemorrhage (aSAH). It has been proposed that pre-admission beta-blocker therapy may lower cerebral vasospasm (cVSP) risk after aSAH; however, this association with other antihypertensives is unknown. We sought to determine the association between antihypertensives and clinical outcomes in aSAH patients.

METHODS

We performed a retrospective study on a prospectively collected cohort of consecutive patients with aSAH who were admitted to an academic center from 2016 to 2021. Association between pre-admission use of antihypertensives and patient outcomes was determined. Primary outcomes included DCI and poor functional outcome at 3 months after discharge defined as modified Rankin scale [mRS] 4-6. The secondary outcome was cVSP identified using transcranial Doppler (TCD).

RESULTS

The cohort consisted of 306 aSAH patients with mean age 57.1 (SD 13.6) years with 187 females (61 %). Although pre-admission use of beta-blockers (OR 0.40, 95 % CI 0.21-80, p = 0.02), calcium channel blockers (OR 0.43, 95 % CI 0.19-0.93, p = 0.035), and thiazide (OR 0.31, 95 % CI 0.11-0.86, p = 0.025) were associated with lower risk of cVSP in univariate analysis, we did not find any association in a multivariate model after adjusting for age. There was no association between any class of antihypertensives and DCI or functional outcome.

CONCLUSION

Pre-admission use of antihypertensive agents may affect TCD findings, however, none of them appear to be independently associated with DCI or functional outcome. Larger prospective studies are needed to establish any potential association.

Endocrine dysregulation in aneurysmal subarachnoid haemorrhage

INTRODUCTION

Aneurysmal Subarachnoid haemorrhage (aSAH) is one of the most common causes of neurocritical care admission. Consistent evidence has been suggestive of endocrine dysregulation in aSAH. This review aims to provide an up-to-date presentation of the available evidence regarding endocrine dysregulation in aneurysmal subarachnoid haemorrhage.

METHODS

A comprehensive literature search was performed using PubMed database. All available evidence related to endocrine dysregulation in hypothalamic-pituitary hormones, adrenal hormones and natriuretic peptides after aSAH, published since 2010, were reviewed.

RESULTS

There have been reports of varying prevalence of dysregulation in hypothalamic-pituitary and adrenal hormones in aSAH. The cause of this dysregulation and its pattern remain unclear. Hypothalamic-pituitary and adrenal dysregulation have been associated with higher incidence of poor neurological outcome and increased mortality. Whilst there is evidence that long-term dysregulation of these axes may also develop, it appears to be less frequent than the acute-phase dysregulation and transient in pattern. Increased levels of catecholamines have been reported in the hyper-acute phase of aSAH with reported inconsistent correlation with the outcomes and the complications of the disease. There is growing evidence that of a causal link between the endocrine dysregulation and the development of hyponatraemia and delayed cerebral ischaemia, in the acute phase of aSAH. However, the pathophysiological mechanism and pattern of endocrine dysregulation which could be causally associated with these complications still remain debatable.

CONCLUSION

The evidence, mainly from small observational and heterogeneous in methodology studies, is suggestive of adverse effects of the endocrine dysregulation on the outcome and the incidence of complications of the disease. However, the cause of this dysregulation and a pathophysiological mechanism that could link its presence with the development of acute complications and the outcome of the aSAH remain unclear. Further research is warranted to elucidate the clinical significance of endocrine dysregulation in subarachnoid haemorrhage.

PD-1+ Monocytes Mediate Cerebral Vasospasm Following Subarachnoid Hemorrhage

BACKGROUND

Cerebral vasospasm is a major source of morbidity and mortality following aneurysm rupture and has limited treatment options.

OBJECTIVE

To evaluate the role of programmed death-1 (PD-1) in cerebral vasospasm.

METHODS

Endovascular internal carotid artery perforation (ICAp) was used to induce cerebral vasospasm in mice. To evaluate the therapeutic potential of targeting PD-1, programmed death ligand-1 (PD-L1) was administered 1 h after ICAp and vasospasm was measured histologically at the level of the ICA bifurcation bilaterally. PD-1 expressing immune cell populations were evaluated by flow cytometry. To correlate these findings to patients and evaluate the potential of PD-1 as a biomarker, monocytes were isolated from the peripheral blood and analyzed by flow cytometry in a cohort of patients with ruptured cerebral aneurysms. The daily frequency of PD-1+ monocytes in the peripheral blood was correlated to transcranial Doppler velocities as well as clinical and radiographic vasospasm.

RESULTS

We found that PD-L1 administration prevented cerebral vasospasm by inhibiting ingress of activated Ly6c+ and CCR2+ monocytes into the brain. Human correlative studies confirmed the presence of PD-1+ monocytes in the peripheral blood of patients with ruptured aneurysms and the frequency of these cells corresponded with cerebral blood flow velocities and clinical vasospasm.

CONCLUSION

Our results identify PD-1+ monocytes as mediators of cerebral vasospasm and support PD-1 agonism as a novel therapeutic strategy.

Beta-Blockade in Aneurysmal Subarachnoid Hemorrhage: a Systematic Review and Meta-Analysis

BACKGROUND/OBJECTIVE

Sympathetic nervous system activation after aneurysmal subarachnoid hemorrhage (aSAH) is associated with complications and poor outcome. In this systematic review and meta-analysis, we investigate the effect of beta-blockers on outcome after aSAH.

METHODS

The review was prospectively registered with PROSPERO (CRD42019111784). We performed a systematic literature search of MEDLINE, EMBASE, the Cochrane Library, published conference proceedings, and abstracts. Eligible studies included both randomized controlled trials and observational studies up to October 2018, reporting the effect of beta-blocker therapy on the following outcomes in aSAH: mortality, vasospasm, delayed cerebral ischemia, infarction or stroke, cardiac dysfunction, and functional outcomes. Studies involving traumatic SAH were excluded. Citations were reviewed, and data extracted independently by two investigators using a standardized proforma.

RESULTS

We identified 819 records with 16 studies (four were randomized controlled trials) including 6702 patients selected for analysis. Exposure to beta-blockade either before or after aSAH was associated with a significant reduction in unadjusted mortality (RR 0.63, 95% CI 0.42-0.93, p = 0.02). A significant reduction in unadjusted mortality was also seen in prospective trials of post-event beta-blockade (RR 0.51, 95% CI 0.28-0.93, p = 0.03). Statistically significant differences were not seen for other outcomes investigated.

CONCLUSIONS

In adult patients with aSAH, beta-blocker therapy is associated with a mortality benefit. Studies are generally of a low quality with considerable clinical heterogeneity. Prospective large interventional trials with patient centered outcomes are required to validate this finding.

Systemic inflammation in hemorrhagic strokes - A novel neurological sign and therapeutic target?

Growing evidences suggest that stroke is a systemic disease affecting many organ systems beyond the brain. Stroke-related systemic inflammatory response and immune dysregulations may play an important role in brain injury, recovery, and stroke outcome. The two main phenomena in stroke-related peripheral immune dysregulations are systemic inflammation and post-stroke immunosuppression. There is emerging evidence suggesting that the spleen contracts following ischemic stroke, activates peripheral immune response and this may further potentiate brain injury. Whether similar brain-immune crosstalk occurs in hemorrhagic strokes such as intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH) is not established. In this review, we systematically examined animal and human evidence to date on peripheral immune responses associated with hemorrhagic strokes. Specifically, we reviewed the impact of clinical systemic inflammatory response syndrome (SIRS), inflammation- and immune-associated biomarkers, the brain-spleen interaction, and cellular mediators of peripheral immune responses to ICH and SAH including regulatory T cells (Tregs). While there is growing data suggesting that peripheral immune dysregulation following hemorrhagic strokes may be important in brain injury pathogenesis and outcome, details of this brain-immune system cross-talk remain insufficiently understood. This is an important unmet scientific need that may lead to novel therapeutic strategies in this highly morbid condition.

The Management of Hypertension in Pre-Aneurysmal Treatment Subarachnoid Hemorrhage Patients

BACKGROUND

Management of hypertension in subarachnoid hemorrhage patients within the preaneurysmal treatment period remains ambiguous, in part due to the lack of high-level, evidence-based guidelines. Despite this, current recommendations offer guidance regarding certain parameters (e.g., mean arterial pressure, systolic blood pressure). However, managing hypertension within this critical period is difficult because a fine balance must be achieved between lowering blood pressure enough to minimize the risk of rebleeding and preventing reduced cerebral perfusion and subsequent ischemic damage. Furthermore, the different causes of hypertension within the preaneurysmal treatment period are polyfactorial and include pathophysiologic responses, sympathetic nervous system activation, and iatrogenic from hyperdynamic therapy and vasopressors, which requires consideration for these patients to receive optimal management. Other factors including loss of autoregulation and concomitant conditions must also be considered when deciding whether to start antihypertensive therapy.

METHODS

We review the literature and provide a comprehensive update on management of hypertension within the preaneurysmal treatment period, which we hope stresses the need for better evidence-based guidelines that will in turn help manage this cohort.

RESULTS

Thorough review revealed no high-grade, evidence-based guidelines to manage these patients, which results in variation in clinical practice among different clinicians and institutions. Despite this, current recommendations seem reasonable until such guidelines are established.

CONCLUSIONS

It is clear that further, larger studies are warranted in order to clarify the effect of antihypertensive therapy on patient outcome and what the BP thresholds are, along with establishing the best treatment, for commencing antihypertensive therapy.

Beta-blocker therapy is not associated with mortality after intracerebral hemorrhage

BACKGROUND

Beta-blocker therapy has been suggested to have neuroprotective properties in the setting of acute stroke; however, the evidence is weak and contradictory. We aimed to examine the effects of pre-admission therapy with beta-blockers (BB) on the mortality following spontaneous intracerebral hemorrhage (ICH).

METHODS

Retrospective analysis of the Helsinki ICH Study database.

RESULTS

A total of 1013 patients with ICH were included in the analysis. Patients taking BB were significantly older, had a higher premorbid mRS score, had more DNR orders, and more comorbidities as atrial fibrillation, hypertension, diabetes mellitus, ischemic heart disease, and heart failure. After adjustment for age, pre-existing comorbidities, and prior use of antithrombotic and antihypertensive medications, no differences in in-hospital mortality (OR 1.1, 95% CI 0.8-1.7), 12-month mortality (OR 1.3, 95% CI 0.9-1.9), and 3-month mortality (OR 1.2, 95% CI 0.8-1.7) emerged.

CONCLUSION

Pre-admission use of BB was not associated with mortality after ICH.