High-Density Lipoprotein Is Associated with Progression of Intracranial Aneurysms

Risk of subarachnoid haemorrhage reduces with blood pressure values below hypertensive thresholds

BACKGROUND

Hypertension is a known risk factor for subarachnoid haemorrhage (SAH). The aim of this study was to describe the relationship between blood pressure and SAH using a large cohort study and perform a meta-analysis of the published literature.

METHODS

Participants in the UK Biobank were followed up via electronic records until 31 March 2017. Cox proportional hazards models were used to analyse the association between baseline blood pressure (systolic blood pressure [SBP], diastolic blood pressure [DBP] and MABP [mean arterial blood pressure]) and subsequent aneurysmal SAH. Linearity was assessed by comparing models including and excluding cubic splines. Electronic databases were searched from inception until 11 February 2022 for studies reporting on blood pressure and SAH.

RESULTS

A total of 500,598 individuals were included with 539 (0.001%) suffering from aneurysmal SAH. Nonlinear models including cubic splines visually appeared linear between SBP of 110 and 180 mmHg and there was minimal difference in fit between linear and nonlinear models. When values were stratified, those with SBP 120-130 mmHg were at higher risk compared to those with SBP <120 mmHg (hazard ratio [HR] 1.41 [1.02, 1.95]). The meta-analysis demonstrated a similar increased risk of SAH in individuals with SBP 120-130 mmHg relative to those with <120 mmHg (HR 1.41 [1.17, 1.72]). A stepwise increase in risk was also seen at each subsequent threshold (130-140 mmHg: HR 1.85 [1.53, 2.24], 140-160 mmHg: HR 2.16 [1.57, 2.98], 160-180 mmHg: HR 2.81 [1.85, 4.29], >180 mmHg: HR 5.84 [1.94, 17.54]).

CONCLUSIONS

The rate of SAH increases linearly with higher SBP in the general population and specifically appears lower in those with SBP <120 mmHg.

Intracranial Aneurysms and Lipid Metabolism Disorders: From Molecular Mechanisms to Clinical Implications

Many vascular diseases are linked to lipid metabolism disorders, which cause lipid accumulation and peroxidation in the vascular wall. These processes lead to degenerative changes in the vessel, such as phenotypic transformation of smooth muscle cells and dysfunction and apoptosis of endothelial cells. In intracranial aneurysms, the coexistence of lipid plaques is often observed, indicating localized lipid metabolism disorders. These disorders may impair the function of the vascular wall or result from it. We summarize the literature on the relationship between lipid metabolism disorders and intracranial aneurysms below.

Endovascular embolization of visceral artery aneurysm: a retrospective study

To assess the safety and efficacy of endovascular embolization techniques, we compared the short- to medium-term prognosis of coil embolization for symptomatic visceral aneurysms (SVAA) and asymptomatic visceral aneurysms (ASVAA) to identify risk factors associated with 30-day mortality. Explore the symptom profile and intrinsic associations of SVAA. A retrospective study of 66 consecutive patients at two tertiary care hospitals from 2010 to 2020 compared the short- to mid-term outcomes of 22 symptomatic VAAs and 44 asymptomatic VAAs treated with coil embolization. Univariate and log-rank tests were used to analyze the prognostic impact of SVAA and ASVAA. SVAA group had significantly higher 30-day mortality than ASVAA group (2(9.1%) vs 0, P = 0.042), both patients who died had symptomatic pseudoaneurysms. Perioperative complications such as end-organ ischemia (P = 0.293) and reintervention (P = 1) were similar in both groups. No difference in event-free survival was identified between the two groups (P = 0.900), but we found that the majority of pseudoaneurysms were SVAA (4/5) and that they had a much higher event rate than true aneurysms. In addition, dyslipidemia may be an influential factor in the development of VAA (P = 0.010). Coil embolization is a safe and effective method of treatment for VAA. Most pseudoaneurysms have symptoms such as abdominal pain and bleeding, and in view of their risk, more attention should be paid to symptomatic patients and the nature of the aneurysm should be determined as soon as possible to determine the next stage of treatment.

Association of elevated neutrophil-to-lymphocyte ratio with increased intracranial aneurysm stability scores and aneurysm growth

BACKGROUND AND PURPOSE

Inflammation involves in the progression of intracranial aneurysms (IAs). However, whether the neutrophil-to-lymphocyte ratio (NLR) as an inflammatory marker links to IAs stability is unidentified. This study was performed to assess the association of the NLR with IAs stability.

METHODS

We retrospectively reviewed the medical records of patients diagnosed with unruptured IAs from January 2014 to June 2018. According to the quartiles of the NLR, patients with unruptured IAs were categorized into four groups. We evaluated the association between the NLR and IAs stability scores and IAs growth. Multiple logistic regression models were used in the analysis.

RESULTS

A significant dose-response association was found between the NLR with IAs stability scores and IAs growth. After adjustment for potential confounders, an elevated NLR (fourth quartile) was associated with increased PHASES score (>5) (adjusted odds ratio [OR], 2.007; 95% confidence interval [CI], 1.361-2.960; p<0.001 [p for trend <0.001]), increased ELAPSS score (>15) (adjusted OR, 1.581; 95% CI, 1.074-2.328; p=0.020 [p for trend =0.001]), increased JAPAN 3-year rupture risk score (>5) (adjusted OR, 1.512; 95% CI, 1.033-2.215; p=0.034 [p for trend <0.001]), and IAs growth (adjusted OR, 16.759; 95% CI, 3.022-92.928; p=0.001 [p for trend <0.001]).

CONCLUSION

An elevated NLR was associated with increased IAs stability scores and IAs growth. The association between NLR and IAs stability need further investigate.

Association between Lipid Levels and Risk for Different Types of Aneurysms: A Mendelian Randomization Study

BACKGROUND

Although the associations between serum lipid levels and aneurysms have been investigated in epidemiological studies, causality remains unknown. Thus, this study aimed to investigate the causal relationships of serum high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), and triglyceride (TG) levels on five types of aneurysms, using genetic variants associated with four lipid traits as instrumental variables in a Mendelian randomization (MR) analysis.

METHODS

We performed two-sample Mendelian randomization (MR) analyses to evaluate the associations of HDL-C, LDL-C, TC, and TG levels with risks for five types of aneurysms and those of LDL-C- (HMGCR, NPC1L1, PCSK9, CETP, and LDLR) and TG-lowering targets (ANGPTL3 and LPL) with aneurysms.

RESULTS

The sample sizes of the included studies ranged from nearly 80,000 to 410,000. We found inverse associations between genetically predicted HDL-C levels and aortic (OR = 0.74, 95% CI = 0.65-0.85) and abdominal aortic aneurysms (0.58, 0.45-0.75). A 1-SD increase in LDL-C and TC levels was associated with increased risks for aortic (1.41, 1.26-1.58 and 1.36, 1.18-1.56, respectively) and abdominal aortic aneurysms (1.82, 1.48-2.22 and 1.55, 1.25-1.93, respectively). TG levels were significantly associated with aortic (1.36, 1.18-1.56) and lower extremity artery aneurysms (2.76, 1.48-5.14), but limited to cerebral aneurysm (1.23, 1.06-1.42). Secondary analyses revealed a relationship between genetically proxied LDL-C-lowering targets and all types of aneurysms; however, the drug targets remained heterogeneous. We found a weak association between TG-lowering therapies and aortic (ANGPTL3, 0.51, 0.29-0.89) and abdominal aortic aneurysms (LPL, 0.64, 0.44-0.94).

CONCLUSION

According to genetic evidence, lipid dysfunction is a causal risk factor for aneurysms. Lipid-lowering drugs may be a potential effective strategy in preventing and managing aneurysms.

Development and Clinical Translation of a Perioperative Nomogram Incorporating Free Fatty Acids to Predict Poor Outcome of Aneurysmal Subarachnoid Hemorrhage Following Endovascular Treatment

Objective: A reliable prediction of clinical outcome is important for clinicians to set appropriate medical strategies in treating patients with aneurysmal subarachnoid hemorrhage (aSAH). In this study, we aim to establish a perioperative nomogram involving serum lipid signatures for predicting poor outcomes at 3 months in patients with aSAH following endovascular therapy.

Methods: Data of patients with aSAH receiving endovascular therapy were collected. Univariable and multivariable analyses were performed to screen independent predictors related to unfavorable outcomes defined by the modified Rankin Scale (mFS) ≥3. A novel nomogram based on these significant features was conducted. The clinical application of this nomogram was assessed by decision curve analysis (DCA) and clinical impact curve.

Results: A total number of patients included in this study were 213 (average age 58.9 years, 65.7% female), representing a poor 3-month outcome rate of 48.8%. Free fatty acid (FFA) levels on admission were efficient in predicting poor outcomes compared with other contents in serum lipids. Univariable and multivariable analyses revealed advanced age (P = 0.034), poor Hunt Hess (HH) (odds ratio, OR = 3.7, P < 0.001) and mFS (OR = 6.0, P < 0.001), aneurysms in the posterior circulation (OR = 4.4, P = 0.019), and higher FFA levels on admission (OR = 3.1, P = 0.021) were negative independent predictors of poor 3 months outcome. A novel nomogram composed of these significant features presented a concordance index (C-index) of 0.831 while the practical benefit was validated by DCA and clinical impact curve. An online calculator based on R programming promoted the clinical application of this nomogram.

Conclusion: Nomogram involving age, HH grade, mFS, aneurysm location, and serum FFA levels was sufficient to provide an individualized prediction of 3-month poor outcome for each patient with aSAH who underwent endovascular therapy.

An association of low high-density lipoprotein levels with recurrence of chronic subdural hematoma

BACKGROUND

Chronic subdural hematoma (CSDH) is a common illness in neurosurgical practice with a substantial recurrence rate. Previous studies found that serum lipids were associated with the risk of stroke and subarachnoid hemorrhage. In the current study, we aimed to identify the relationship between serum lipids and CSDH recurrence.

METHODS

The medical records of 274 consecutive surgical patients with CSDH in our department were reviewed and analyzed. Patients were separated into recurrence and non-recurrence groups. Univariable and multivariable Cox proportional hazards regression analyses were performed to identify serum lipids (triglycerides, total cholesterol, LDL, HDL) and other potential predictors associated with CSDH recurrence, and the performance of predictors was assessed with receiver operating characteristic (ROC) curve.

RESULTS

Of the 274 patients included in the study, 42 (15.3%) experienced at least 1 recurrence of CSDH. Univariate analysis showed that age, hypertension, diabetes mellitus, anticoagulant use, triglycerides, HDL, and midline shift were all significantly associated with CSDH recurrence. Multivariable Cox regression analysis found that only age, diabetes mellitus, midline shift, and HDL level were independent risk factors for CSDH recurrence. A higher HDL level (HR = 0.929, 95% CI 0.905-0.953) was significantly associated with a lower risk of recurrence, and ROC curve analysis revealed that the optimal HDL cut-off value as a predictor was 37.45 mg/dl.

CONCLUSIONS

Low level of high-density lipoprotein is significantly associated with recurrence of chronic subdural hematoma.

Computational fluid dynamics analysis of intracranial aneurysms treated with flow diverters: A case report

INTRODUCTION

Intracranial aneurysms (IAs) are localized dilatations of intracranial arteries due to weaknesses of the endothelial layer. IAs may be treated by flow diverters (FDs), alternatively to stents and coils combination. FD is a method for the treatment of IAs especially for large, wide-necked or fusiform aneurysms. In this case report, we described a 65-year-old woman with IA who were treated by FD.

CASE PRESENTATION

A 65-year-old woman was diagnosed with a giant aneurysm at the posterior inferior cerebellar artery segment of the left internal carotid artery. Then based on the computed tomography data of this woman, aneurysm vascular stent model was constructed before and after FD, and internal pressure, velocity, wall shear stress (WSS) of aneurysms were determined by CFD analysis. Standard boundary conditions were applied. It was found that a single FD stent and double FD stents decreased the blood flow and WSS of aneurysm. The effect of single FD stent+30% filling on blood flow was more obvious, but the aneurysm rupture was caused by excessive coil packing. So, a single stent+10% coil packing rate was the best option for treating aneurysms.

CONCLUSIONS

CFD analysis for flow velocity and WSS have protection on aneurysms.

Testosterone aggravates cerebral vascular injury by reducing plasma HDL levels

Testosterone is often used to improve the physiological function. But increased testosterone levels affect blood lipids and cause inflammation and oxidative stress, which are risk factors for vascular diseases. This study aimed at investigating the effects of testosterone on cerebral vascular injury using an established intracranial aneurysm (IA) model. Sixteen-week-old female C57Bl/6 mice were subcutaneously infused with testosterone propionate (TP; 5 mg/kg day) or plain soybean oil (controls) for 6 weeks. After 2 weeks of treatment, mice were given angiotensin II-elastase for another 4 weeks. The results showed that TP significantly increased cell apoptosis and reactive oxygen species production in cerebral artery, together with increases in plasma tumor necrosis factor-α (TNF-α) levels and in urinary 8-isoprostane levels. Plasma assays showed that 2 weeks after TP or soybean oil administration, the high-density lipoprotein (HDL) level was higher in the TP group than in controls. In vitro studies showed that testosterone increased TNF-α and monocyte chemotactic protein-1 mRNA and protein expression levels in RAW 264.7 macrophages. In summary, by reducing the HDL level, TP aggravates cerebral artery injury by increasing cell apoptosis, inflammation, and oxidative stress.