Comparison of cerebral perfusion in perimesencephalic subarachnoid hemorrhage and aneurysmal subarachnoid hemorrhage

Treatment of Cerebral Vasospasm Following Aneurysmal Subarachnoid Hemorrhage using the Neurospeed Semi-compliant Balloon

BACKGROUND AND PURPOSE

Cerebral vasospasm (CV) following aneurysmal subarachnoid hemorrhage (aSAH) may lead to morbidity and mortality. Endovascular mechanical angioplasty may be performed if symptomatic CV is refractory to noninvasive medical management. Off-label compliant remodelling balloons tend to conform to the course of the vessel, contrary to noncompliant or semi-compliant balloons. Our objective is to describe our initial experience with the semi-compliant Neurospeed balloon (approved for intracranial stenosis) in cerebral vasospasm treatment following aSAH.

METHODS

All patients included in the prospective observational SAVEBRAIN PWI (NCT05276934 on clinicaltrial.gov) study who underwent cerebral angioplasty using the Neurospeed balloon for the treatment of medically refractory and symptomatic CV after aSAH were identified. Patient demographic information, procedural details and outcomes were obtained from electronic medical records.

RESULTS

Between February 2022 and June 2023, 8 consecutive patients underwent CV treatment with the Neurospeed balloon. Angioplasty of 48 arterial segments (supraclinoid internal carotid artery, A1 and A2 segments of the anterior cerebral artery, M1 and M2 segments of the middle cerebral artery) was attempted and 44/48 (92%) were performed. The vessel diameter significantly improved following angioplasty (+81%), while brain hypoperfusion decreased (-81% of the mean TMax). There was no long-term clinical complication, 4% periprocedural complications occurred.

CONCLUSION

The semi-compliant Neurospeed balloon is effective in the treatment of cerebral vasospasm following aSAH, bringing a new device into the armamentarium of the neurointerventionalist to perform intracranial angioplasty.

Predictive value of CT perfusion-derived parameters in Moyamoya disease

OBJECTIVE

To explore the applicability of CT perfusion-derived parameters and collateral index in prediction of functional and clinical outcomes in patients with Moyamoya disease (MMD) who have not been treated surgically.

METHODS

All hemispheres were categorized into four groups: those with ischemic (IS) lesions, hemorrhagic (HE) lesions, subarachnoid hemorrhage (SAH) and normal hemisphere (NH). The clinical review included primary outcomes (whether a patient survived the cerebrovascular event) and secondary outcomes (the modified Rankin scale [mRS] and Katz-activity of daily living [ADL] scale). CTP-derived parameters of the frontal, temporal lobe and basal ganglia were calculated. Collateral index of the hypointensity ratio (HIR) was defined as a volume of Tmax >10 s/ Tmax >4 s.

RESULTS

Between December 2020 and December 2021, 21 MMD patients (15 bilateral cases and 6 unilateral cases, for a total of 36 hemispheres) were retrospectively included. Compared with the NH group, the IS group showed obviously abnormal hemodynamics. As for the primary outcomes, HIR showed an excellent area under the curve of 0.955 (95 % CI: 0.886-1.000, p < 0.001). Significant correlations were found between CTP-derived parameters and secondary outcomes. Furthermore, HIR was significantly correlated with mRS (r = 0.576, p = 0.001) and ADL scores (r = 0.644, p < 0.001).

CONCLUSION

Among different imaging types, IS hemispheres were characterized by distinct changes of hemodynamic parameters. Collateral index of HIR could be considered a clinically accessible and promising indictor of functional and clinical outcomes in MMD.

Current status of perimesencephalic non-aneurysmal subarachnoid hemorrhage

Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSAH) is a distinctive disease, representing SAH centered in perimesencephalic cisterns, with negative angiography findings. In recent years, the number of patients with PNSAH has increased significantly; however, the knowledge of PNSAH is insufficient. Therefore, we performed a review of the literature from a PubMed search and recounted our understanding of PNSAH. In this review, we summarized that current high-resolution computed tomography angiography is an acceptable replacement for digital subtraction angiography to rule out aneurysms in PNSAH with strict criteria. The current hypothesis about the etiology of PNSAH is that there is deep vein rupture from aberrant venous anatomy and increased intracranial venous pressure. PNSAH is associated with mild symptoms and lower rates of hydrocephalus and symptomatic vasospasm. For PNSAH, conservative treatment has been the mainstream treatment. PNSAH has a benign clinical course and an excellent prognosis; in long-term follow-up, re-bleeding and death were uncommon.

TNF-R1 Correlates with Cerebral Perfusion and Acute Ischemia Following Subarachnoid Hemorrhage

BACKGROUND

Early cerebral hypoperfusion and ischemia occur after subarachnoid hemorrhage (SAH) and influence clinical prognosis. Pathophysiological mechanisms possibly involve inflammatory mediators. TNF-α has been associated with complications and prognosis after SAH. We investigated the relation of perfusion parameters and ischemic lesions, with levels of TNF-α main receptor, TNF-R1, after SAH, and their association with prognosis.

METHODS

We included consecutive SAH patients admitted within the first 72 h of SAH onset. Blood samples were simultaneously collected from a peripheral vein and from the parent artery of the aneurysm. Levels of TNF-R1 were measured using ELISA (R&D Systems Inc., USA). CT perfusion and MRI studies were performed in the first 72 h. Correlation and logistic regression analysis were used to identify outcome predictors.

RESULTS

We analyzed 41 patients. Increased levels of TNF-R1 correlated with increased T_max (arterial: r = -0.37, p = 0.01) and prolonged MTT (arterial: r = 0.355, p = 0.012; venous: r = 0.306, p = 0.026). Increased levels of both arterial and venous TNF-R1 were associated with increased number of lesions on DWI (p = 0.006). In multivariate analysis, venous TNFR1 levels > 1742.2 pg/mL (OR 1.78; 95%CI 1.18-2.67; p = 0.006) and DWI lesions (OR 14.01; 95%CI 1.19-165.3; p = 0.036) were both independent predictors of poor outcome (mRS ≥ 3) at 6 months.

CONCLUSION

Increased levels of TNF-R1 in arterial and venous blood correlate with worse cerebral perfusion and with increased burden of acute ischemic lesions in the first 72 h after SAH. Venous levels of TNF-R1 and DWI lesions were associated with poor outcome at 6 months. These results highlight the pathophysiological role of TNF-α pathways in SAH and suggest a possible role of combined imaging and laboratorial markers in determining prognosis in acute SAH.

Ischemic Lesions in Acute and Subacute Perimesencephalic Subarachnoid Hemorrhage

OBJECTIVE

Perimesencephalic hemorrhage (PMH) is a subtype of nonaneurysmal subarachnoid hemorrhage (SAH). In patients with aneurysmal SAH, the occurrence of acute ischemic lesions is associated with severity and poor outcome. We investigated the frequency of ischemic lesions on DWI in patients with PMH and compared it with the frequency of ischemic lesions in patients with aneurysmal SAH.

SUBJECTS AND METHODS

From a prospective cohort of 80 patients with acute spontaneous SAH, we included 15 patients with PMH and 39 patients with aneurysmal SAH who were matched on the basis of their clinical condition (World Federation of Neurological Societies grade 1 or 2). MRI was performed less than 72 hours after SAH, 8-10 days after SAH, or at both points in time. The number and distribution of lesions previously seen on DWI that were also seen on a second MRI examination were assessed. Nonparametric tests were used to compare groups.

RESULTS

Early acute ischemic lesions (those identified < 72 hours after SAH) were found in 46.2% of patients with PMH and in 62.9% of patients with aneurysmal SAH. No significant differences in the number of acute ischemic lesions between groups were noted less than 72 hours after SAH (median, 0.5 lesion [interquartile range {IQR}, two lesions] in patients with PMH vs one lesion [IQR, three lesions] in patients with aneurysmal SAH [p = 0.48] or 8-10 days after SAH (median, 0.5 lesion [IQR, four lesions] in patients with PMH vs 1.5 lesions [IQR, three lesions] in patients with aneurysmal SAH [p = 0.26]). However, 58.3% of patients with aneurysmal SAH had new infarcts at 8-10 days, compared with 7.1% of patients with PMH. Patients with PMH had diffuse ischemic lesions, whereas patients with aneurysmal SAH in the anterior circulation had mainly supratentorial lesions.

CONCLUSION

Early ischemic lesions appeared on DWI both in patients with PMH and in patients with aneurysmal SAH. The number of lesions increased during the time window for vasospasm, mainly in patients with aneurysmal SAH. Further studies are required to better understand the pathophysiologic mechanisms behind early ischemia in patients with PMH and their impact on prognosis.

The Acute Phase of Experimental Subarachnoid Hemorrhage: Intracranial Pressure Dynamics and Their Effect on Cerebral Blood Flow and Autoregulation

Clinical presentation and neurological outcome in subarachnoid hemorrhage (SAH) is highly variable. Aneurysmal SAH (aSAH) is hallmarked by sudden increase of intracranial pressure (ICP) and acute hypoperfusion contributing to early brain injury (EBI) and worse outcome, while milder or non-aneurysmal SAH with comparable amount of blood are associated with better neurological outcome, possibly due to less dramatic changes in ICP. Acute pressure dynamics may therefore be an important pathophysiological aspect determining neurological complications and outcome. We investigated the influence of ICP variability on acute changes after SAH by modulating injection velocity and composition in an experimental model of SAH. Five hundred microliters of arterial blood (AB) or normal saline (NS) were injected intracisternally over 1 (AB₁, NS₁), 10 (AB_10, NS₁₀), or 30 min (AB₃₀) with monitoring for 6 h (n = 68). Rapid blood injection resulted in highest ICP peaks (AB₁ median 142.7 mmHg [1.Q 116.7-3.Q 230.6], AB₃₀ 33.42 mmHg [18.8-38.3], p < 0.001) and most severe hypoperfusion (AB₁ 16.6% [11.3-30.6], AB₃₀ 44.2% [34.8-59.8]; p < 0.05). However, after 30 min, all blood groups showed comparable ICP elevation and prolonged hypoperfusion. Cerebral autoregulation was disrupted initially due to the immediate ICP increase in all groups except NS₁₀; only AB₁, however, resulted in sustained impairment of autoregulation, as well as early neuronal cell loss. Rapidity and composition of hemorrhage resulted in characteristic hyperacute hemodynamic changes, with comparable hypoperfusion despite different ICP ranges. Only rapid ICP increase was associated with pronounced and early, but sustained disruption of cerebral autoregulation, possibly contributing to EBI.