Arterial stiffness as a risk factor for cerebral aneurysm

The relationship between intraoperative surrogates of vascular stiffness, cerebral aneurysms, and surgical outcomes

OBJECTIVE

Increased arterial stiffness has been linked to aneurysm formation in the systemic and cerebral circulations, though the role played by arterial stiffness in the cerebral vasculature continues to be refined. This study assesses whether intraoperative surrogates of arterial stiffness differ between patients with cerebral aneurysms and controls, and the extend that these indices relate to outcomes following open surgical treatment.

METHODS

We evaluated patients in a prospectively maintained database who underwent cerebral aneurysm surgery, and compared them to controls without cerebral aneurysms. Arterial stiffness was estimated using the intraoperative ambulatory arterial stiffness index (AASI) and average pulse pressure (PP).

RESULTS

We analyzed 214 cerebral aneurysm patients and 234 controls. Patients in the aneurysm group were predominantly female and had a higher incidence of hypertension, diabetes mellitus, and vascular disease. They also demonstrate elevated AASI and average PP. When stratified by the occurrence of subarachnoid hemorrhage (SAH) or unfavorable neurological outcome, the AASI and average PP were not highly associated with the occurrence of SAH but were highly associated with unfavorable neurological outcomes. After multivariable analysis, both the AASI and average PP were no longer associated with unfavorable neurological outcomes, however elevated age, strongly linked with arterial stiffness, became a key predictive variable.

CONCLUSION

Readily obtained intraoperative surrogates of arterial stiffening demonstrates its presence in those with cerebral aneurysm disease and the extent that it does it may meaningfully direct their clinical course. However, multivariable analysis demonstrates limitations of using arterial stiffness measures to predict clinical outcomes.

Imaging markers of intracranial aneurysm development: A systematic review

BACKGROUND

Imaging markers of intracranial aneurysm (IA) development are not well established.

PURPOSE

To provide an overview of imaging markers of IA development.

METHODS

A systematic search of PubMed and Embase up to December 1st 2020 using predefined criteria. Thirty-six studies met our inclusion criteria. We performed a quantitative summary of the included studies.

RESULTS

We found converging evidence for A1 segment asymmetry as an anatomical marker of anterior communicating artery (Acom) aneurysm development, and moderate evidence for several other markers. No hemodynamic markers yielded converging or moderate evidence. There was large heterogeneity across studies, especially in the definitions of imaging markers and study outcomes used. Due to the poor methodological quality of many studies and unavailability of effect sizes or crude data to calculate effect sizes, a formal meta-analysis was not possible. Many studies had poor methodological quality and varied inmarkerdefinitions and outcome measuresused, which prevented us from performing a formal meta-analysis.

CONCLUSIONS

We only identified A1 segment asymmetry as an imaging marker of Acom aneurysm development with converging evidence. A meta-analysis was not possible due to the heterogeneity of marker definitions and outcomes used, and poor methodological quality of many studies. Future studies should use robust study designs and uniformly defined imaging markers and outcome measures.

Impact of cerebral aneurysm size on distal intracranial hemodynamics and changes following flow diversion

BACKGROUND

The impact of cerebral aneurysm size on distal intracranial hemodynamics such as arterial pressure and Pulsatility Index is not completely understood, either before or after flow diversion.

OBJECTIVE

The aim of the study is to assess the impact of aneurysm size on distal Pulsatility Index and pressure before and after flow diversion.

METHODS

From December 2015, prospective measurement of middle cerebral artery pressure and Pulsatility Index was performed in consecutive patients with unruptured cerebral aneurysms in the cavernous to communicating segments of the internal carotid artery, which were treated with single flow diversion. Pressure and Pulsatility Index were recorded at the M1-segment ipsilateral to the cerebral aneurysm. Ratio of middle cerebral artery to radial arterial pressure (pressure ratio) was calculated to control for variations in systemic blood pressure. Correlations between aneurysm size and pressure ratio and Pulsatility Index were assessed before and after treatment.

RESULTS

A total of 28 aneurysms were treated. The mean aneurysm size was 7.2 mm. Aneurysm size correlated linearly with systolic pressure ratio (1% pressure ratio increase per mm aneurysm size increase, P = 0.002, r² = 0.33), mean pressure ratio (0.6% per mm, P = 0.03, r² = 0.17) and Pulsatility Index (5% Pulsatility Index increase per mm, P = 0.003, r² = 0.43). After flow diversion, aneurysm size preserved a linear correlation with the systolic pressure ratio (1% per mm, P = 0.004, r²  =  0.28), but not with the mean pressure ratio (0.4% per mm, P = 0.15, r² < 0.1) or Pulsatility Index (0.3% per mm, P = 0.78, r² < 0.1).

CONCLUSION

Aneurysm size affects distal hemodynamics: patients with larger aneurysms have increased systolic and mean pressure ratio, and increased Pulsatility Index. After flow diversion, mean pressure ratio and Pulsatility Index no longer associate with the aneurysm size, suggesting an effect of the flow diversion also on distal intracranial hemodynamics.

Association between estimated pulse wave velocity and the risk of stroke in middle-aged men

BACKGROUND

Increased aortic stiffness, assessed as carotid-femoral pulse wave velocity (cfPWV), contributes to cerebrovascular damage and is predictive of cerebrovascular events.

AIMS AND METHODS

We sought to examine the association between estimated pulse wave velocity (ePWV), a proxy of carotid-femoral pulse wave velocity, and stroke and its subtypes (ischemic and hemorrhagic) in a prospective cohort of 2666 men (aged mean 53.1, range 42-61 years) enrolled in the Kuopio Ischemic Heart Disease cohort study.

RESULTS

During a median 28-year follow-up, 471 incident stroke (397 ischemic and 94 hemorrhagic) events occurred. After adjusting for several established and emerging risk factors including age and pulse pressure, comparing the p versus bottom quartiles of ePWV, there was an increased risk of stroke (hazard ratio [HR] 2.37, 95% Confidence Interval [CI]: 1.57-3.58), ischemic stroke (HR 2.23, 95% CI, 1.42-3.50), and hemorrhagic stroke (HR 3.57, 95% CI, 1.45-8.76).

CONCLUSION

These findings demonstrate that ePWV is independently associated with the risk of stroke in middle-aged men.

[Possibilities of application of cardio-ankle vascular index in patients with cerebrovascular diseases]

This publication focuses on the feasibility of using the cardio-ankle vascular index (CAVI) in patients with cerebrovascular diseases. The authors consider the pathological conditions and risk factors of stroke associated with increased arterial stiffness, methods for its assessment, the advantages of using CAVI, the experience of using CAVI in patients with cardiovascular diseases, in particular, in neurological patients. The complexity of the application of CAVI in the Russian population, promising directions for determining the index in neurology as well as the importance of CAVI borderline indicators are shown. It is emphasized that stroke patients should be screened with a mandatory study of CAVI.

Increased Arterial Stiffness is a Predictor of Delayed Ischaemic Stroke After Subarachnoid Haemorrhage

BACKGROUND

Subarachnoid haemorrhage (SAH) accounts for 5-10% of strokes and its prognosis may be influenced by different complications, including delayed cerebral ischaemia (DCI). The pathophysiology of DCI is complex and still unknown. Many different mechanisms may contribute to the occurrence of DCI. Arterial stiffness (AS), a well-known risk factor for cardiovascular events, also associated with the development and rupture of cerebral aneurysms, may represent a novel contributing risk factor. The aim of our study was to investigate a possible link between AS and DCI after SAH.

METHOD

Fifty-nine (59) patients with SAH (age [mean±standard deviation], 62±12 years) underwent neuroimaging examination, and 24-hour heart rate and blood pressure monitoring, including AS index (ASI) measurement.

RESULTS

Of 59 patients, DCI occurred in 12. ASI was significantly higher in patients with DCI than in patients without it (0.70±0.1 vs 0.62±0.1; p=0.03). ASI was a significant predictor for DCI (odds ratio [for an increase of 0.20 points in ASI], 5.99; 95% confidence interval, 1.23-29.22; p=0.03).

CONCLUSIONS

Arterial stiffness index is a simple and inexpensive tool that is able to predict the risk of DCI in patients with SAH. This marker can impact on intensive care unit monitoring, early recognition, and treatment, contributing to optimal acute management of patients with SAH.

Brachial-Ankle Pulse Wave Velocity as a Predictor of Silent Cerebral Embolism after Carotid Artery Stenting

BACKGROUND

In neuroendovascular therapy, the effect of arterial stiffness on postprocedural cerebral thromboembolism is unknown. In this observational study, we examined the relationship between cerebral thromboembolism after carotid artery stenting and arterial stiffness.

METHODS

From April 2015 to February 2017, we enrolled consecutive patients undergoing scheduled carotid artery stenting in our institution. In all patients, preprocedural brachial-ankle pulse wave velocity was used to assess arterial stiffness, whereas the number of new cerebral ischemic lesions on diffusion-weighted magnetic resonance imaging was assessed after treatment. We also analyzed patient data and details of procedures in patients with carotid artery stenting.

RESULTS

Twenty-one patients completed the study. The mean brachial-ankle pulse wave velocity was 1879 cm/s. There was no association of cerebral thromboembolisms with age, unstable plaque, protection device, or type of stent. However, the brachial-ankle pulse wave velocity was an independent predictor of cerebral thromboembolisms (P = .0017).

CONCLUSIONS

Brachial-ankle pulse wave velocity is predictive of silent cerebral embolisms on diffusion-weighted magnetic resonance imaging after carotid artery stenting.

Study on the role of Cathepsin B and JNK signaling pathway in the development of cerebral aneurysm

OBJECTIVE

To investigate the correlation between JNK signal and the apoptosis of VSMC as well as the expression of Cathepsin B and to explore the role of JNK signal in the development of cerebral aneurysm.

METHODS

Rat models of cerebral aneurysm were established and histopathologic changes of cerebral aneurysm and the apoptosis of VSMC were analyzed. Rat models were respectively subject to subcutaneous injection of Cathepsin B siRNA and JNK inhibitor SP600125. Western blot technique was used to detect the expression of proteins like Cathepsin B, Caspase-3, and p-JNK. Spearman's rho was used to examine the correlation between p-JNK and Cathepsin B, as well as the expression of relevant proteins.

RESULTS

The success rate of modeling rats with cerebral aneurysm was 88.75%. After the respective injection of Cathepsin B siRNA, SP600125 and their combination, the cell densities of VSMC of rats with cerebral aneurysm all increased significantly (P < 0.05 or P < 0.01), but the apoptosis rate of VSMC decreased significantly (P < 0.01). Compared with normal rats, the expression of Cathepsin B, Caspase-3 and p-JNK in Cerebral aneurysm models increased significantly. Effectively intervening Cathepsin B genes with Cathepsin B siRNA could significantly inhibit the expression of Cathepsin B and Caspase-3, but hardly influence the expression of p-JNK. JNK inhibitor SP600125 had no influence on the expression of Cathepsin B and Caspase-3, but effectively inhibited the expression of p-JNK. In cerebral aneurysm tissues, positive correlation was observed between the expression of p-JNK and Cathepsin B, the correlation coefficient was r = 0.640.

CONCLUSION

After the attack of cerebral aneurysm, proteins like Cathepsin B, Caspase-3 and p-JNK are all involved in the apoptosis of VSMCs. This process may be realized by Cathepsin B which activates the apoptosis mechanism of Caspase-3 and mediate the apoptosis of VSMC through the JNK signaling pathway. Therefore, silencing Cathepsin B gene or inhibiting the conduction through JNK signaling pathway can mitigate the apoptosis of vascular smooth muscle cells in cerebral aneurysm.