Possible increase in insulin resistance and concealed glucose-coupled potassium-lowering mechanisms during acute coronary syndrome documented by covariance structure analysis

Inhibitory action of B-type natriuretic peptide on adrenocorticotropic hormone in patients with acute coronary syndrome

In addition to the classical actions of hemodynamic regulation, natriuretic peptides (NPs) interact with various neurohumoral factors that are deeply involved in the pathophysiology of cardiovascular diseases. However, their effects on the hypothalamic-pituitary-adrenal (HPA) axis, which is activated under acute high-stress conditions in acute coronary syndrome (ACS), remain largely unknown. We investigated the impact of plasma B-type NP (BNP) on plasma adrenocorticotropic hormone (ACTH)-cortisol levels during the acute phase of ACS ischemic attacks. The study population included 436 consecutive patients with ACS for whom data were collected during emergency cardiac catheterization. Among them, biochemical data after acute-phase treatment were available in 320 cases, defined as the ACS-remission phase (ACS-rem). Multiple regression analyses revealed that plasma BNP levels were significantly negatively associated with plasma ACTH levels only during ACS attacks (P < 0.001), but not in ACS-rem, whereas plasma BNP levels were not significantly associated with plasma cortisol levels at any point. Accordingly, covariance structure analyses were performed to clarify the direct contribution of BNP to ACTH by excluding other confounding factors, confirming that BNP level was negatively correlated with ACTH level only during ACS attacks (β = -0.152, P = 0.002), whereas BNP did not significantly affect ACTH in ACS-rem. In conclusion, despite the lack of a significant direct association with cortisol levels, BNP negatively regulated ACTH levels during the acute phase of an ACS attack in which the HPA axis ought to be activated. NP may alleviate the acute stress response induced by severe ischemic attacks in patients with ACS.NEW & NOTEWORTHY BNP negatively regulates ACTH during a severe ischemic attack of ACS in which hypothalamic-pituitary-adrenal axis ought to be activated, indicating an important role of natriuretic peptides as a mechanism of adaptation to acute critical stress conditions in humans.

Possible diverse contribution of coronary risk factors to left ventricular systolic and diastolic cavity sizes

It is generally believed that risk factors damage the coronary arteries, cause myocardial ischemia, and consequently change the shape of the heart. On the other hand, each of the risk factors may also have a negative effect on the heart. However, it is very difficult to examine the effects of each of these risk factors independently. Therefore, it is necessary to select an appropriate statistical method and apply it efficiently. In this study, the effects of coronary risk factors on left ventricular size and cardiac function were investigated using structure equation modeling (SEM), and were shown as Bayesian SEM-based frequency polygons using selected two-dimensional contours. This study showed that each risk factor directly affected the shape of the heart. Because vascular risk and heart failure risk are likely to evolve at the same time, managing risk factors is very important in reducing the heart failure pandemic.

Serum electrolyte/metabolite abnormalities among patients with acute myocardial infarction: comparison between patients with and without diabetes mellitus

Background: Diabetes mellitus (DM) in a setting of acute myocardial infarction (AMI) is associated with significant metabolic changes and worse outcomes.Objective: To evaluate the prevalence and the prognostic significance of electrolyte/metabolite disturbances among AMI patients with vs. without DM.Methods: Patients admitted to a tertiary medical center with AMI throughout 2002-2012 were screened. Exclusion criteria were: dialysis, mechanical ventilation, and in-hospital coronary artery bypass graft (CABG) surgery. All the results of the following analyses were obtained: Glucose, Uric Acid, (UA) Calcium, Magnesium, Albumin, Potassium, and Sodium. The primary outcome was in-hospital all-cause mortality.Results: A total of 14,364 AMI patient admissions was evaluated, mean age 68.1 ± 14.4 years, 65.5% males, and 41.2% with DM. Following an adjustment to potential confounders, DM patients had increased risk for significant hyperglycemia, hyperuricemia, hypercalcemia, hypomagnesemia, hyperkalemia, and hyponatremia as well as significantly decreased risk for hypoglycemia, hypermagnesemia, and hypokalemia compared with nondiabetics. Overall, 681 (4.7%) patients died throughout the index admission. Deceased had an increased incidence of electrolyte/metabolite abnormalities versus hospital survivors. The prognostic significance of the different categories of the investigated variables is very similar among diabetics and nondiabetics, except increased and decreased uric acid levels [<4.5 (men); <4.0 (women) and ≥9.0 (men); ≥9.4 (women)] which are associated with worse outcomes among diabetics while hyperglycemia (Glucose ≥213 mg/dL) and increased Potassium levels (Potassium ≥4.4mEq/L) which comprise significantly worse prognosis among nondiabetics.Conclusions: Patients with DM admitted with AMI are at greater risk for electrolyte/metabolite abnormalities which are associated with increased risk for in-hospital mortality. The latter association is similar among patients with and without DM except for hyperglycemia and increased potassium levels (stronger among nondiabetics).

Possible Association Between Body Temperature and B-Type Natriuretic Peptide in Patients With Cardiovascular Diseases

BACKGROUND

In addition to various biological effects of natriuretic peptides (NP) on cardiovascular systems, we recently reported that NP raises intracellular temperature in cultured adipocytes. We herein examined the possible thermogenic action of NP in consideration of hemodynamic parameters and inflammatory reaction by proposing structural equation models.

METHODS AND RESULTS

The study population consisted of 1985 consecutive patients who underwent cardiac catheterization. Covariance structure analyses were performed to clarify the direct contribution of plasma B-type NP (BNP) to body temperature (BT) by excluding other confounding factors. A hierarchical path model showed increase in BNP, increase in C-reactive protein and decrease in left ventricular ejection fraction were mutually associated. As expected, C-reactive protein was positively correlated with BT. Importantly, despite a negative correlation between BNP and left ventricular ejection fraction, a decrease in the left ventricular ejection fraction was associated with BT decrease, whereas elevation in BNP level was associated with BT increase independently of C-reactive protein level (P = .007).

CONCLUSIONS

Patients with LV dysfunction tend to manifest a decrease in BT, whereas BNP elevation is associated with an increase in BT independently of inflammatory response. These findings suggest the adaptive heat-retaining property of NP (and/or NP-associated factors) when BT falls owing to unfavorable hemodynamic conditions in a state of impaired cardiac function.

Potassium levels as a marker of imminent acute kidney injury among patients admitted with acute myocardial infarction. Soroka Acute Myocardial Infarction II (SAMI-II) Project

BACKGROUND

Acute kidney injury (AKI) is a common complication following acute myocardial infarction (AMI) and associated with worse outcomes. Serum Potassium levels (K, mEq/L), which are regulated by the kidneys, are related with poor prognosis in patients with AMI.

OBJECTIV

To evaluate whether K levels predict imminent AKI in patients with AMI.

METHODS

This retrospective nested case-control study was based on medical records of hospitalized AMI patients, 2002-2012. The cases (AKI group) were defined as an increase of ≥1.5-fold in serum creatinine level or a decrease of ≥25% in the estimated glomerular filtration rate (eGFR) during the hospitalization. The control group comprised of matched randomly selected patients that did not develop AKI. For both groups, all creatinine and K levels were obtained for up-to 72 h prior to the AKI diagnosis (index time).

RESULTS

A total of 12,498/17,678 admissions met the inclusion criteria. The AKI and the control groups consisted of 430 and 1345 matched admission respectively. K levels, prior AKI diagnosis seemed to be higher in the AKI group. Multivariate analysis showed that K ≥ 4.5 within 36-56 h prior to the index time was an independent predictor of the subsequent AKI, OR = 2.3, p < .001. The c-statistic of the model was 0.859, p < .001. Predictivity of K for AKI was stronger among ST-elevation (STEMI) vs. Non-ST-elevation AMI (NSTEMI) patients (OR = 4, p < .001 vs. 1.7, p = .025 respectively; p-for-interaction = 0.038).

CONCLUSIONS

K ≥ 4.5 is an independent and incremental marker of imminent AKI in patients with AMI, predictivity is stronger in patients with STEMI than NSTEMI.

Revealing the Common Mechanisms of Scutellarin in Angina Pectoris and Ischemic Stroke Treatment via a Network Pharmacology Approach

OBJECTIVE

To investigate the shared mechanisms of scutellarin in angina pectoris (AP) and ischemic stroke (IS) treatment.

METHODS

A network pharmacology approach was used to detect the potential mechanisms of scutellarin in AP and IS treatment by target prediction, protein-protein interaction (PPI) data collection, network construction, network analysis, and enrichment analysis. Furthermore, molecular docking simulation was employed to analyze the interaction between scutellarin and core targets.

RESULTS

Two networks were established, including a disease-target network and a PPI network of scutellarin targets against AP and IS. Network analysis showed that 14 targets, namely, AKT1, VEGFA, JUN, ALB, MTOR, ESR1, MAPK8, HSP90AA1, NOS3, SERPINE1, FGA, F2, FOXO3, and STAT1, might be the therapeutic targets of scutellarin in AP and IS. Among them, NOS3 and F2 were recognized as the core targets. Additionally, molecular docking simulation confifirmed that scutellarin exhibited a relatively high potential for binding to the active sites of NOS3 and F2. Furthermore, enrichment analysis indicated that scutellarin might exert a therapeutic role in both AP and IS by regulating several important pathways, such as coagulation cascades, mitogen-activated protein kinase (MAPK) signaling pathway, phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway, Toll-like receptor signaling pathway, hypoxia inducible factor-1 (HIF-1) signaling pathway, forkhead box O (FoxO) signaling pathway, tumor necrosis factor (TNF) signaling pathway, adipocytokine signaling pathway, insulin signaling pathway, insulin resistance, and estrogen signaling pathway.

CONCLUSIONS

The shared underlying mechanisms of scutellarin on AP and IS treatment might be strongly associated with its vasorelaxant, anticoagulant, anti-inflammatory, and antioxidative effects as well as its effect on improving lipid metabolism.

The association of concomitant serum potassium and glucose levels and in-hospital mortality in patients with acute myocardial infarction (AMI). Soroka acute myocardial infarction II (SAMI-II) project

BACKGROUND

Acute myocardial infarction (AMI) is associated with significant systemic metabolic changes. These changes include increased plasma concentrations of counter-regulatory hormones and changes in potassium (K, mEq/L) and glucose (mg/dL) levels. The latter are associated with outcomes and investigated as potential focus for intervention; glucose-insulin‑potassium (GIK) solution.

OBJECTIVES

To evaluate the associations of concomitant K and glucose (K/glucose) levels with in-hospital mortality in AMI patients.

METHODS

AMI patients hospitalized in a tertiary Medical Center through 2002-2012 were studied. K/glucose levels were divided into equally sized categories. The intermediate category (glucose 124-143 mg/dL, K 4-4.9 mEq/L) was the reference group. The associations of these tests with the outcome were assessed using Generalized Estimating Equations model which included the interaction of K and glucose levels, adjusted for the patient's baseline characteristics and other laboratory results.

RESULTS

17,670 AMI admissions (mean age 67.8 ± 4.0 years, 66.6% males, mortality rate 7.7%) were included; 112,531 results of K/glucose tests were recorded. Univariate and multivariate analyses showed that K/glucose levels were significantly associated with in-hospital mortality, with highest risk being in patients with concomitant low K (<3.7 mEq/L) and high glucose (≥217 mg/dL), adjOR = 2.53. It seems that low-normal glucose levels attenuate the increased risk associated with low K.

CONCLUSIONS

The highest independent risk for mortality is found with low K and concomitant high glucose levels. Additional studies evaluating mechanisms and therapeutic interventions in K/glucose levels in this setting are warranted.

Collaborative Activities of Noradrenaline and Natriuretic Peptide for Glucose Utilization in Patients with Acute Coronary Syndrome

Glucose is an important preferential substrate for energy metabolism during acute coronary syndrome (ACS) attack, although insulin resistance (IR) increases during ACS. Increasing evidence indicates that natriuretic peptides (NP) regulate glucose homeostasis. We investigated possible compensatory actions of NP in collaboration with other neurohumoral factors that facilitate glucose utilization during ACS. The study population consisted of 1072 consecutive cases with ischemic heart disease who underwent cardiac catheterization (ACS, n = 216; non-ACS, n = 856). Among ACS subjects, biochemical data after acute-phase treatment were available in 91 cases, defined as ACS-remission phase (ACS-rem). Path models based on covariance structure analyses were proposed to clarify the direct contribution of B-type NP (BNP) and noradrenaline to glucose and HOMA-IR levels while eliminating confounding biases. In non-ACS and ACS-rem subjects, although noradrenaline slightly increased glucose and/or HOMA-IR levels (P < 0.03), BNP did not significantly affect them. In contrast, in ACS subjects, high noradrenaline was a significant cause of increases in glucose and HOMA-IR levels (P < 0.001), whereas high BNP was a significant cause of decreases in both parameters (P < 0.005). These findings indicate that BNP and noradrenaline coordinately activate glucose metabolism during ACS, with noradrenaline increasing glucose levels, as an energy substrate, while BNP improves IR and promotes glucose utilization.

Association between plasma B-type natriuretic peptide and anaemia in heart failure with or without ischaemic heart disease: a retrospective study

OBJECTIVES

Anaemia is a risk of worsening heart failure. However, anaemia sometimes remains undetected because the superficial cardiac function does not precisely reflect the adverse impact of anaemia. Plasma B-type natriuretic peptide (BNP) could be helpful in these cases. However, the direct anaemic effects on BNP remain unknown. Herein, we compared the direct effect of anaemia on BNP and left ventricular ejection fraction (LVEF) using an advanced statistical procedure.

DESIGN

A retrospective study.

SETTING

Secondary care (cardiology), single-centre study.

PARTICIPANTS

The study consisted of 3756 inpatients, including 684 without ischaemic heart disease (IHD) and 3072 with IHD.

PRIMARY AND SECONDARY OUTCOME MEASURES

Relationship between plasma BNP levels and LVEF values.

RESULTS

A path model was constructed to simultaneously examine the adverse impact of anaemia on LVEF and plasma BNP, allowing for renal function. The path model revealed that LVEF increased in response to low haemoglobin (Hb), and the phenomenon was prominent in non-IHD (standardised regression coefficients (St.β): -0.264, p<0.001) rather than in IHD (St.β: 0.015, p=0.531). However, the response of BNP was commonly observed in both groups (non-IHD St.β: -0.238, IHD St.β: -0.398, p<0.001, respectively). Additionally, this study showed a direct link between low estimated glomerular filtration rate and high BNP independently of LVEF. Incrementally, Bayesian structural equation modelling in covariance structure analysis clearly supported this result. The scatter plots and simple regression analysis revealed that an adequate blood supply was approximately Hb 110 g/L and over in the non-IHD patients, whereas blood was not supplied in sufficient quantities even by Hb 130 g/L in patients with IHD.

CONCLUSION

The current study demonstrated that anaemia was a substantial risk for worsening cardiac overload as estimated by plasma BNP. The anaemic response of LVEF likely changed depending on underlying cardiac disorders (IHD or not). However, the response of BNP was robustly observed.

High Serum Uric Acid is Highly Associated with a Reduced Left Ventricular Ejection Fraction Rather than Increased Plasma B-type Natriuretic Peptide in Patients with Cardiovascular Diseases

High serum uric acid (UA) has been reported to be associated with left ventricular (LV) dysfunction; however, the relationship between UA and plasma B-type natriuretic peptide (BNP), a sensitive biomarker of heart failure, is still unclear. This study investigated their relationship to provide an accurate assessment of high UA. The study patients consisted of 3,077 subjects who underwent cardiac catheterization because of various cardiovascular disorders. Since the explanatory factors of multiple regression analysis were mostly confounding with each other, subgroup analysis was performed by quartering the study population using the respective risk factors and by covariance structure analysis. This analysis revealed that UA was almost always well associated with a reduced LV ejection fraction (LVEF), but generally not with BNP. UA was significantly associated with BNP in lean aged females, but not in obese adolescent males, although LVEF was significantly reduced in response to a high UA in both groups. A high UA is a direct risk factor for cardiac dysfunction from the perspective of BNP; however, augmentation of BNP in response to a high UA would likely be restricted among obese adolescent males. On the other hand, the observed LV systolic dysfunction, such as LVEF, reflects a high UA on an almost constant basis.

Predictors of oxygenation impairment in medical treatment for type B acute aortic dissection

Lung oxygenation impairment often occurs in patients with type B acute aortic dissection (AAD), necessitating mechanical ventilation. Patients receiving mechanical ventilation are at risk of complications, so a low-oxygen condition requiring mechanical ventilation should be avoided. We explored the predictors of oxygenation impairment. We enrolled 46 patients with type B AAD who had been medically treated and underwent computed tomography. Blood was sampled to measure markers of inflammation, such as the C-reactive protein (CRP) levels and white blood cell count. The arterial partial pressure of oxygen/fraction of inspired oxygen ratio (PaO₂/FiO₂) was calculated to quantify the severity of respiratory failure. Spearman's rank correlation analysis revealed that the minimum PaO₂/FiO₂ ratio was significantly correlated with gender, age, and current smoker, and the peak CRP, body temperature, and D-dimer values. A multivariate regression analysis revealed that younger age, male sex, and the peak CRP level were significant predictors of the minimum PaO₂/FiO₂ ratio (P = 0.01, 0.035 and 0.005, respectively). A covariance structure analysis showed that a younger age and the peak CRP level were significant predictors of oxygenation impairment in type B AAD. Oxygenation impairment in type B AAD is correlated with younger age and a higher peak CRP level. This will enable the identification of patients whose respiratory condition is susceptible to worsening and help prevent mechanical ventilation, leading to the provision of appropriate therapy.

Increased Levels of Cardiac Troponin I in Subjects with Extremely Low B-type Natriuretic Peptide Levels

Because of the lack of studies focused on the biological implications of extremely low B-type natriuretic peptide (BNP) levels, we investigated whether extremely low BNP levels could be harmful to the cardiovascular system due to compromised cardio-protection. By using cardiac troponin I (cTnI) as an indicator of cardiovascular disorder, we assessed whether cTnI was inversely associated with BNP in populations with low BNP levels. A total of 2,001 apparently healthy subjects older than 38 years were included in this study. We defined subgroups from this population by limiting the maximum BNP level with cut-off values ranging from 1 through 20 pg/mL and performed covariance structure analyses by comparing log(BNP) with log(cTnI) in each subgroup. The beta values between log(BNP) and log(cTnI) sharply decreased as the BNP cut-off was reduced from 20 pg/mL (beta = 0.04) to 1 pg/mL (beta = −0.29) and became significant when the BNP cut-off levels were lower than 4 pg/mL (p < 0.005). In subgroups with BNP levels lower than 4 pg/mL, elevation in cTnI level was inversely associated with BNP (p < 0.005), which suggests that insufficient BNP may play a pathogenic role in the occurrence of cardiovascular abnormalities.

Conflicting relationship between age-dependent disorders, valvular heart disease and coronary artery disease by covariance structure analysis: Possible contribution of natriuretic peptide

Background

It is conceivable that contemporary valvular heart disease (VHD) is affected largely by an age-dependent atherosclerotic process, which is similar to that observed in coronary artery disease (CAD). However, a comorbid condition of VHD and CAD has not been precisely examined. The first objective of this study was to examine a possible comorbid condition. Provided that there is no comorbidity, the second objective was to search for the possible reasons by using conventional risk factors and plasma B-type natriuretic peptide (BNP) because BNP has a potentiality to suppress atherosclerotic development.

Methods

The study population consisted of 3,457 patients consecutively admitted to our institution. The possible comorbid condition of VHD and CAD and the factors that influence the comorbidity were examined by covariance structure analysis and multivariate analysis.

Results

The distribution of the patients with VHD and those with CAD in the histograms showed that the incidence of VHD and the severity of CAD rose with seniority in appearance. The real statistical analysis was planned by covariance structure analysis. The current path model revealed that aging was associated with VHD and CAD severity (P < 0.001 for each); however, as a notable result, there was an inverse association regarding the comorbid condition between VHD and CAD (Correlation coefficient [β]: -0.121, P < 0.001). As the second objective, to clarify the factors leading to this inverse association, the contribution of conventional risk factors, such as age, gender, hypertension, smoking, diabetes, obesity and dyslipidemia, to VHD and CAD were examined by multivariate analysis. However, these factors did not exert an opposing effect on VHD and CAD, and the inverse association defied explanation. Since different pathological mechanisms may contribute to the formation of VHD and CAD, a differentially proposed path model using plasma BNP revealed that an increase in plasma BNP being drawn by VHD suppressed the progression of CAD (β: -0.465, P < 0.001).

Conclusions

The incidence of VHD and CAD showed a significant conflicting relationship. This result supported the likely presence of unknown diverse mechanisms on top of the common cascade of atherosclerosis. Among them, the continuous elevation of plasma BNP due to VHD might be one of the explicable factors suppressing the progression of CAD.