Blood pressure and collateral circulation in acute ischemic stroke.

BACKGROUND: This study aimed to evaluate the effect of different blood pressure (BP) parameters on the collateral circulation in a retrospective cohort of patients with acute ischemic stroke and ipsilateral internal carotid artery (ICA) occlusion. METHODS: The degree of intracranial collaterals was graded according to the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) Collateral Flow Grading System. At 12-72 h after stroke onset, six BP measurements were obtained in 124 patients with ICA occlusion. Baseline clinical and imaging characteristics were collected. Group comparisons were performed, and the collateral score (CS) was assessed and entered into a logistic regression analysis. RESULTS: In all, 80 (64.5%) patients displayed good collateral filling (CS ≥ 2). Good intracranial collaterals were more frequently associated with the development of collaterals in the anterior communicating artery, posterior communicating artery, and leptomeningeal artery. The systolic blood pressure (SBP; p = 0.018), diastolic blood pressure (DBP; p = 0.013), and mean arterial pressure (MAP; p = 0.016) were significantly associated with good CS. Median CS was highest when SBP was 120-130 mm Hg (p = 0.034). Logistic regression analysis showed that hypertension (p = 0.026, OR: 0.380, 95% CI: 0.163-0.890) was a significant predictor of poor CS. CONCLUSION: The development of collateral circulation in patients with acute ischemic stroke with ICA occlusion may be influenced by BP. A moderately decreased SBP is associated with good integrity of the collateral circulation in patients with acute ischemic stroke with occlusion of the ICA.

Inhibition of 14q32 MicroRNAs miR-329, miR-487b, miR-494, and miR-495 increases neovascularization and blood flow recovery after ischemia.

RATIONALE: Effective neovascularization is crucial for recovery after cardiovascular events. OBJECTIVE: Because microRNAs regulate expression of up to several hundred target genes, we set out to identify microRNAs that target genes in all pathways of the multifactorial neovascularization process. Using www.targetscan.org, we performed a reverse target prediction analysis on a set of 197 genes involved in neovascularization. We found enrichment of binding sites for 27 microRNAs in a single microRNA gene cluster. Microarray analyses showed upregulation of 14q32 microRNAs during neovascularization in mice after single femoral artery ligation. METHODS AND RESULTS: Gene silencing oligonucleotides (GSOs) were used to inhibit 4 14q32 microRNAs, miR-329, miR-487b, miR-494, and miR-495, 1 day before double femoral artery ligation. Blood flow recovery was followed by laser Doppler perfusion imaging. All 4 GSOs clearly improved blood flow recovery after ischemia. Mice treated with GSO-495 or GSO-329 showed increased perfusion already after 3 days (30% perfusion versus 15% in control), and those treated with GSO-329 showed a full recovery of perfusion after 7 days (versus 60% in control). Increased collateral artery diameters (arteriogenesis) were observed in adductor muscles of GSO-treated mice, as well as increased capillary densities (angiogenesis) in the ischemic soleus muscle. In vitro, treatment with GSOs led to increased sprout formation and increased arterial endothelial cell proliferation, as well as to increased arterial myofibroblast proliferation. CONCLUSIONS: The 14q32 microRNA gene cluster is highly involved in neovascularization. Inhibition of 14q32 microRNAs miR-329, miR-487b, miR-494, and miR-495 provides a promising tool for future therapeutic neovascularization.

Increased Plasma Non-High-Density Lipoprotein Levels and Poor Coronary Collateral Circulation in Patients With Stable Coronary Artery Disease.

BACKGROUND: This study investigated the relationship between coronary collateral circulation (CCC) and non-high-density lipoprotein cholesterol (non-HDL-C) in patients with stable coronary artery disease (CAD). Coronary collateral circulation plays a critical role in supporting blood flow, particularly in the ischemic myocardium. Previous studies show that non-HDL-C plays a more important role in the formation and progression of atherosclerosis than do standard lipid parameters. METHODS: A total of 226 patients with stable CAD and stenosis of more than 95% in at least 1 epicardial coronary artery were included in the study. Rentrop classification was used to assign patients into group 1 (n = 85; poor collateral) or 2 (n = 141; good collateral). To adjust for the observed imbalance in baseline covariates between study groups, propensity-score matching was used. Covariates were diabetes, Gensini score, and angiotensin-converting enzyme inhibitor use. RESULTS: In the propensity-matched population, the plasma non-HDL-C level (mean [SD], 177.86 [44.0] mg/dL vs 155.6 [46.21] mg/dL; P = .001) was statistically higher in the poor-collateral group. LDL-C (odds ratio [OR], 1.23; 95% CI, 1.11-1.30; P = .01), non-HDL-C (OR, 1.34; 95% CI, 1.20-1.51; P = .01), C-reactive protein (OR, 1.21; 95% CI, 1.11-1.32; P = .03), systemic immune-inflammation index (OR, 1.14; 95% CI, 1.05-1.21; P = .01), and C-reactive protein to albumin ratio (OR, 1.11; 95% CI, 1.06-1.17; P = .01) remained independent predictors of CCC in multivariate logistic regression analysis. CONCLUSION: Non-HDL-C was an independent risk factor for developing poor CCC in stable CAD.

Correlation between Serum Erythropoietin and Cerebral Collateral Flow in Acute Ischemic Stroke Patient.

BACKGROUND: Erythropoietin (EPO), which is associated with anemia, exerts neuroprotective effects in ischemic stroke. In cases of stenosis or narrowing of the main cerebral blood vessel, the prognosis is favorable if collateral blood circulation is well developed in acute stroke. Several studies have investigated the relationship between EPO administration and stroke outcomes. The present study investigated the correlation between serum EPO level and cerebral collateral circulation, which could result in favorable clinical outcomes. METHODS: The study subjects were patients diagnosed with acute ischemic stroke who underwent initial brain magnetic resonance imaging between January 2020 and March 2022. Following brain computed tomography perfusion for collateral flow, serum EPO levels were measured. Collaterals were assessed according to the Mass system and divided into good collateral (GC) or poor collateral (PC) groups. Serum EPO levels were determined using a chemiluminescence immunoassay method. A correlation coefficient analysis was conducted to determine the correlation between serum EPO levels and GC. A receiver operating characteristic curve analysis determined the cutoff value of EPO for GC. RESULTS: Serum EPO levels were significantly higher in the GC than that in the PC group (P<0.05). The cut-off level of serum EPO for a good outcome was 9.1 mIU/mL. CONCLUSION: A high serum EPO (>9.1 mIU/mL) could be a marker of GC in patients with acute ischemic stroke that predicts good clinical outcomes.

Internal Trapping of an Acutely Ruptured Dissecting Aneurysm of a Dominant Vertebral Artery Following Balloon Test Occlusion: A Case Report.

Objective: To report a case of an acutely ruptured vertebral artery dissecting aneurysm (VADA) with a hypoplastic contralateral vertebral artery (VA) successfully treated with internal trapping following the estimation of the collateral flow from anterior circulation. Case Presentation: A 46-year-old woman was diagnosed with subarachnoid hemorrhage and acute hydrocephalus. Ventriculostomy was performed under general anesthesia. CTA revealed a left VADA distal to the origin of the left posterior inferior cerebellar artery (PICA). The right VA was hypoplastic, and the right posterior communicating artery (Pcom) was fetal type. We performed balloon test occlusion (BTO) of the VA proximal to the origin of the left PICA and estimated sufficient collateral blood flow via the right Pcom and basilar artery (BA) to the anterior spinal artery (ASA) and the left PICA. Internal trapping of the left VADA was then performed. The angiograms after internal trapping revealed collateral flow from the right Pcom to the BA, and the hypoplastic right VA perfused the proximal BA and ASA. She recovered without any neurological deficits following antiplatelet therapy and vasospasm treatment. She was followed up for 6 years without any neurological events occurring. Conclusion: When BTO indicates sufficient collateral flow, internal trapping could be a useful treatment for acutely ruptured VADAs on the dominant side, given a complete understanding of the angioarchitecture and the risk of vasospasm due to subarachnoid hemorrhage.

Assessment of Myocardial Collateral Blood Flow with Contrast Echocardiography.

Humans have pre-formed collateral vessels that enlarge with ischemia. In addition, new vessels can be formed within ischemic zones from pre-formed endocardial arcades of vessels providing rich collateral flow. Collateral flow under resting conditions (if >25% of normal) is enough to maintain myocardial viability, but may be insufficient to prevent myocardial ischemia under stress. Coronary angiography is a poor tool for collateral flow assessment. Myocardial contrast echocardiography is arguably the gold standard for experimental and clinical measurement of collateral flow. This review describes several experimental and clinical studies that highlight the importance of the collateral circulation in coronary artery disease.

Assessment of Myocardial Collateral Blood Flow with Contrast Echocardiography

Humans have pre-formed collateral vessels that enlarge with ischemia. In addition, new vessels can be formed within ischemic zones from pre-formed endocardial arcades of vessels providing rich collateral flow. Collateral flow under resting conditions (if >25% of normal) is enough to maintain myocardial viability, but may be insufficient to prevent myocardial ischemia under stress. Coronary angiography is a poor tool for collateral flow assessment. Myocardial contrast echocardiography is arguably the gold standard for experimental and clinical measurement of collateral flow. This review describes several experimental and clinical studies that highlight the importance of the collateral circulation in coronary artery disease.

Intermittent exercise promotes collateral circulation in ischemic myocardial tissue / 中华物理医学与康复杂志

Objective To observe whether appropriate intermittent exercise at the ischemic threshold can safely promote collateral circulation in an ischemic area of the myocardium through the increased expression of vascular endothelial growth factor(VEGF)and its receptor fetal liver kinase-1(Fik-1). Methods A balloon constrictor was surgically implanted in the first obtuse marginal coronary artery(OM1)of miniature pigs.The subjects were divided into 3 groups:a sham-operation group,a pure ischemia group,and an exercise training group.Subjects in the exercise training group performed individualized treadmill programs 30 min daily,5 d per week,for 8 weeks,including 2 two-minute episodes of exercise-induced ischemia.Two pre-exercise episodes of pure ischemia induced by brief OM1 occlusion were also conducted.Only pure ischemia was induced in the pure ischemia group,and the sham-operation group remained sedentary for the experimental period.Relative myocardial blood flow(RMBF)was measured using microspheres.VEGF and Flk-1 expression levels were measured by Western blotting and real time RT-PCR analyses.Cardiac troponin I(ctnI)levels were determined using an enzyme-linked immunosorbent assay(ELISA). Light and electron microscopy were employed to examine myocardia damage in the ischemic area.Results RMBFs in the exercise training group were significantly higher than those in the pure ischemia and sham-operation groups. RMBFs in the pure ischemia group were significantly higher than those in the sham-operation group.The expression of VEGF and Flk-1 proteins and mRNAs in the exercise training group were significantly higher than those in the pure ischemia and sham-operation groups,and the levels in the pure ischemia group were also significantly higher than those in the sham-operation group.After training,no myocardial damage and no ctnI increase was observed in the pure ischemia group.Microscopy revealed no obvious structural changes. Conclusion Intermittent exercise at the isehemia threshold intension can safely promote coronary collateral formation through upregulation of VEGF and Flk-1 expression in the ischemic myocardial area of a porcine model.