Potent influence of obesity on suppression of plasma B-type natriuretic peptide levels in patients with acute heart failure: An approach using covariance structure analysis

Unique crosstalk between platelet and leukocyte counts during treatment for acute coronary syndrome: A retrospective observational study

In the pathophysiology of acute coronary syndrome (ACS), platelet (PLT) and neutrophil (Neu) crosstalk may be important for activating coagulation and inflammation. It has been speculated that PLTs and Neu may affect each other's cell counts; however, few studies have investigated this hypothesis. In this study, we measured changes in blood cell counts in 245 patients with ACS during treatment and investigated the mutual effects of each blood cell type. Path diagrams were drawn using structural equation modeling, and temporal changes in the count of each blood cell type and the relevance of these changes were analyzed. Throughout the treatment period, the numbers of all blood cell types (red blood cells [RBCs], leukocytes, and PLTs) were associated with each other before and after treatment. A detailed examination of the different cell types revealed that the PLT count at admission had a significant positive effect on the leukocyte (especially Neu) count after treatment. Conversely, the leukocyte (especially Neu) count at admission had a significant positive effect on the PLT count after treatment. During ACS, PLTs and leukocytes, especially Neu, stimulate each other to increase their numbers. The formation of a PLT-leukocyte complex may increase coagulation activity and inflammation, which can lead to a further increase in the counts of both blood cell types.

Close linkage between blood total ketone body levels and B-type natriuretic peptide levels in patients with cardiovascular disorders

In patients with cardiovascular disorders, blood total ketone body (TKB) levels increase with worsening heart failure and are consumed as an alternative fuel to fatty acid and glucose. We investigated factors contributing to the increase in the blood TKB levels in patients with cardiovascular disorders. The study population consisted of 1030 consecutive patients who underwent cardiac catheterization. Covariance structure analyses were performed to clarify the direct contribution of hemodynamic parameters, including the left ventricular end-diastolic pressure (LVEDP), left ventricular end-systolic volume index (LVESVI), left ventricular end-diastolic volume index (LVEDVI), and B-type natriuretic peptide (BNP) levels, to TKB by excluding other confounding factors. These analyses showed that the TKB levels were significantly associated with the BNP level (P = 0.003) but not the LVEDP, LVESVI, or LVEDVI levels. This was clearly demonstrated on a two-dimensional contour line by Bayesian structure equation modeling. The TKB level was positively correlated with the BNP level, but not LVEDP, LVESVI or LVEDVI. These findings suggested that elevated blood TKB levels were more strongly stimulated by the increase in BNP than by hemodynamic deterioration. BNP might induce the elevation of TKB levels for use as an important alternative fuel in the failing heart.

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.

Diagnostic and prognostic considerations for use of natriuretic peptides in obese patients with heart failure

Natriuretic peptides (NPs, B-type natriuretic peptide /BNP and NT-proBNP) are universally used biomarkers with established cut-points to aid in the diagnosis of heart failure (HF). It has been demonstrated that an inverse relationship exists between obesity, defined by the body mass index (BMI), and NPs, such that the application of NPs to diagnostic algorithms in HF remains challenging in overweight and obese patients. Some have advocated that lowering the cut-offs for NPs or using a correction for high BMI may improve the diagnostic accuracy in obese individuals. The inverse relationship of NPs with high BMI is present in both HF with reduced (HFrEF) and with preserved (HFpEF) ejection fraction, although levels tend to be higher in HFrEF. Nevertheless, data from several studies have shown that the prognostic value of NPs is preserved across BMI classes, and that increasing circulating levels of NPs correlate with adverse outcomes including all-cause mortality and HF hospitalizations. While NPs can still be used in diagnosis of HF in obese individuals, lower thresholds and the clinical context should be utilized in decision making. Additionally, given the validated prognostic value even in obesity, NPs can be employed in risk-stratification of individuals with obesity and HF, although there remains limited evidence about use in those with severe obesity (BMI >40 kg/m²).

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.

Increase in oxidized low-density lipoprotein level according to hyperglycemia in patients with cardiovascular disease: A study by structure equation modeling

AIMS

Malondialdehyde-modified low-density lipoprotein (MDA-LDL) level has been reported to be strongly associated with the pathogenesis of cardiovascular diseases. We focused on diabetic status and investigated its possible contribution to MDA-LDL level.

METHODS

The study sample consisted of 2705 patients who were admitted to our hospital and underwent cardiac catheterization. Blood samples were obtained to measure the levels of fasting blood sugar (FBS), hemoglobin A1c (HbA1c), insulin, LDL, MDA-LDL and others. Body mass index (BMI) was also used in constructing structural equation modeling and Bayesian estimation.

RESULTS

To explore the factors theoretically associated with MDA-LDL level, we performed structural equation modeling. We generated a path model that revealed that BMI, LDL level and FBS were significantly associated with MDA-LDL level (P < 0.001 for each factor), whereas insulin level and HbA1c level were not significantly associated (P = NS for both factors). Noted above was clearly demonstrated on the image of 2-D contour line by Bayesian structure equation modeling.

CONCLUSIONS

This study clearly showed that hyperglycemia affects MDA-LDL level. An interaction between diabetes and dyslipidemia was shown in terms of activation of lipid oxidation.

A Highly-sensitized Response of B-type Natriuretic Peptide to Cardiac Ischaemia Quantified by Intracoronary Pressure Measurements

B-type natriuretic peptide (BNP) secretion is stimulated by cardiac dysfunction. However, it is unclear how finely myocardial ischaemia contributes to BNP secretion and whether increases in BNP secretion contribute to coronary vasodilation. This study investigated the direct interaction between plasma BNP levels and cardiac ischaemia using the baseline distal-to-aortic pressure ratio (Pd/Pa). We examined the baseline Pd/Pa and fractional flow reserve (FFR) in 167 patients with intermediate coronary stenosis. The plasma BNP level appeared to be associated with the baseline Pd/Pa in the study population, and this association appeared to become clear only in patients with an FFR ≤ 0.80. To examine the effect of the baseline Pd/Pa on the BNP level in these patients, structural equation modeling (SEM) was performed. The baseline Pd/Pa significantly affected the BNP level (β: -0.37, p = 0.003) and the left ventricular ejection fraction (β: 0.43, p = 0.001). To examine the role of BNP in coronary vasodilation, we proposed another path model using a novel value obtained by dividing the FFR by the baseline Pd/Pa (FFR/baseline Pd/Pa) as an index of the hyperaemic response. The BNP level significantly affected the FFR/baseline Pd/Pa (β: 0.48, p = 0.037). This study demonstrated that BNP finely responded to an exacerbation of cardiac ischaemia and that increases in BNP secretion effectively ameliorated coronary vasoconstriction.

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.

Obese phenotype and natriuretic peptides in patients with heart failure with preserved ejection fraction

The results of several recent experimental studies using animal models and clinical trials suggested that obesity is not merely an epiphenomenon or a prominent comorbidity in patients with heart failure (HF). Indeed, recent studies suggest that obesity is intimately involved in the pathogenesis of HF with preserved ejection fraction (HFpEF). The most recent studies indicate that approximately 50% of HF patients have HFpEF. As standard pharmacological treatment usually shows only a weak or even neutral effect on primary outcomes in patients with HFpEF, treatment strategies targeted to specific groups of HFpEF patients, such as those with obesity, may increase the likelihood of reaching substantial clinical benefit. Considering the well-known inverse relationship between body mass index (BMI) values and B-type natriuretic peptide (BNP) levels, it is theoretically conceivable that the measurement of natriuretic peptides, using cutoff values adjusted for age and BMI, should increase diagnostic and prognostic accuracy in HFpEF patients. However, further experimental studies and clinical trials are needed to differentiate and better understand specific mechanisms of the various HFpEF phenotypes, including obese HFpEF.

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.

Complex assessment of patients with decompensated heart failure: The clinical value of impedance cardiography and N-terminal pro-brain natriuretic peptide

BACKGROUND

Acute decompensated heart failure (ADHF) is a serious clinical problem and a condition requiring immediate diagnostics, supporting the therapeutic decision adequate to the specific ADHF mechanism. N-terminal pro-brain natriuretic peptide (NT-proBNP) is an established biochemical marker of heart failure, strongly related to hemodynamic status. Impedance cardiography (ICG) provides non-invasive hemodynamic assessment that can be performed immediately at the bedside and revealed to be useful diagnostic tool in some clinical settings in cardiology.

OBJECTIVES

The aim of this study was to evaluate the usefulness of ICG in the admission diagnostics and monitoring the effects of treatment in patients hospitalized due to ADHF, with special emphasis on its relation to NT-proBNP.

METHODS

This study enrolled 102 patients, aged over 18 years, hospitalized due to ADHF. The subjects underwent detailed clinical assessment, including ICG and NT-proBNP at admission and at discharge day.

RESULTS

Among all analyzed ICG parameters thoracic fluid content (TFC), a marker of chest overload, was the most significantly correlated with NT-proBNP level (R = 0.46; p = 0.000001). In comparison with patients with low thoracic fluid content (TFC ≤ 35/kΩ), those with higher TFC values (>35/kΩ) exhibited a greater severity of symptoms (NYHA functional class); higher NT-proBNP levels; lower left ventricular ejection fraction (LVEF), stroke index (SI), and cardiac index (CI); as well as significantly higher systemic vascular resistance index (SVRI). These TFC-based subgroups showed no significant differences in terms of heart rate (HR), systolic blood pressure (SBP), or diastolic blood pressure (DBP).

CONCLUSIONS

The evaluation of hemodynamic parameters, especially TFC, seems to be a worthwhile addition to standard diagnostics, both at the stage of hospital admission and while monitoring the effects of treatment. Impedance cardiography is a useful method in evaluating individual hemodynamic profiles in patients with ADHF.

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.

Close linkage between serum uric acid and cardiac dysfunction in patients with ischemic heart disease according to covariance structure analysis

High serum uric acid (UA) level has been assumed to be a risk factor for left ventricular (LV) dysfunction; however, the precise relationship between these conditions has not been fully examined because many confounding factors are associated with UA level. We herein examined the precise relationship by proposing structural equation models. The study population consisted of 1432 cases with ischemic heart disease who underwent cardiac catheterization. Multiple regression analyses and covariance structure analyses were performed to elucidate the cause-and-effect relationship between UA level and LV ejection fraction (LVEF). A path model exploring the factors contributing to LVEF showed that high UA was a significant cause of reduced LVEF (P = 0.004), independent of other significant factors. The degree of atherosclerosis, as estimated by the number of diseased coronary vessels, was significantly affected by high UA (P = 0.005); and the number of diseased coronary vessels subsequently led to reduced LVEF (P < 0.001). Another path model exploring the factors contributing to UA level showed that LVEF was a significant cause of high UA (P = 0.001), while other risk factors were also independent contributing factors. This study clearly demonstrated that there was a close link between high UA and LV dysfunction, which was represented by possible cause-and-effect relationship.

Associations between Left Ventricular Cavity Size and Cardiac Function and Overload Determined by Natriuretic Peptide Levels and a Covariance Structure Analysis

The effects of left ventricular (LV) cavity size on cardiac function and overload have not yet been fully elucidated. We performed a covariance structure analysis and drew theoretical path models to clarify the effects of hemodynamic parameters on the stroke volume index (SVI) as a marker of cardiac function and on the plasma B-type natriuretic peptide (BNP) level as a marker of cardiac overload. We simultaneously measured various hemodynamic parameters and the BNP levels during cardiac catheterization in 1,715 inpatients of our institution. The current path models tested the validity of the Frank-Starling law in patients with heart failure using the SVI, the LV end-systolic volume index (LVESVI) and the LV end-diastolic volume index (LVEDVI). Using the BNP levels, the path models clearly demonstrated that LVESVI substantially augmented cardiac overload, whereas LVEDVI palliated this parameter. These volume indices exerted opposite effects on cardiac function and overload. These results advance the understanding of the relationships between LV cavity size and both cardiac function and overload and indicate the increasing importance of LV diastolic volume in heart failure and the utility of LVESVI as an important marker of cardiac remodeling for further relevant studies.

Manifold implications of obesity in ischemic heart disease among Japanese patients according to covariance structure analysis: Low reactivity of B-type natriuretic peptide as an intervening risk factor

Background/Objectives

Obesity is believed to be one of the major risk factors for cardiovascular disease in Western countries. However, the effects of obesity should be continuously examined in the Japanese population because the average bodily habitus differs among countries. In this study, we collectively examined the significance of obesity and obesity-triggered risk factors including the low reactivity of B-type natriuretic peptide (BNP), for ischemic heart disease (IHD) in Japanese patients.

Methods and results

The study patients consisted of 1252 subjects (IHD: n = 970; non-IHD: n = 282). Multiple logistic regression analysis revealed that dyslipidemia, hypertension, diabetes, and the low reactivity of BNP were significant risk factors for IHD, but body mass index (BMI) was not. A theoretical path model was proposed by positioning BMI at the top of the hierarchical model. Exploratory factor analysis revealed that BMI did not play a causative role in IHD (P = NS). BMI was causatively linked to other risk factors (P<0.001 for hypertension; P<0.001 for dyslipidemia; P<0.001 for HbA1c; P<0.001 for LogBNP), and these factors played a causative role in IHD (P<0.001 for hypertension; P<0.001 for dyslipidemia; P<0.001 for HbA1c; P<0.001 for LogBNP). The intrinsic power of the low reactivity of BNP induced by high BMI on the promotion of IHD was fairly potent.

Conclusion

This study demonstrated that obesity per se is not a strong risk factor for IHD in Japanese patients. However, several important risk factors triggered by obesity exhibited a causative role for IHD. The low reactivity of BNP is a substantial risk factor for IHD.

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

Objective

Although glucose-insulin-potassium (GIK) therapy ought to be beneficial for ischemic heart disease in general, variable outcomes in many clinical trials of GIK in acute coronary syndrome (ACS) had a controversial impact. This study was designed to examine whether “insulin resistance” is involved in ACS and to clarify other potential intrinsic compensatory mechanisms for GIK tolerance through highly statistical procedure.

Methods and results

We compared the degree of insulin resistance during ACS attack and remission phase after treatment in individual patients (n = 104). During ACS, homeostasis model assessment of insulin resistance (HOMA-IR) values were significantly increased (P<0.001), while serum potassium levels were transiently decreased (degree of which was indicated by ΔK) (P<0.001). This finding provides a renewed paradox, as ΔK, a surrogate marker of intrinsic GIK cascade activation, probably reflects the validated glucose metabolism during ischemic attack. Indeed, multiple regression analysis revealed that plasma glucose level during ACS was positively correlated with ΔK (P = 0.026), whereas HOMA-IR had no impact on ΔK. This positive correlation between ΔK and glucose was confirmed by covariance structure analysis with a strong impact (β: 0.398, P = 0.015). Intriguingly, a higher incidence of myocardial infarction relative to unstable angina pectoris, as well as a longer hospitalization period were observed in patients with larger ΔK, indicating that ΔK also reflects disease severity of ACS.

Conclusions

Insulin resistance most likely increases during ACS; however, ΔK was positively correlated with plasma glucose level, which overwhelmed insulin resistance condition. The present study with covariance structure analysis suggests that there are potential endogenous glucose-coupled potassium lowering mechanisms, other than insulin, regulating glucose metabolism during ACS.

Parallel comparison of risk factors between progression of organic stenosis in the coronary arteries and onset of acute coronary syndrome by covariance structure analysis

Background

It is widely accepted that progression of organic stenosis in the coronary arteries and onset of acute coronary syndrome (ACS) are similar in the development of atherosclerosis. However, the extent of the association of each risk factor with the respective pathological conditions has not been fully elucidated.

Objectives

We investigated the differences in risk factors between these conditions using a statistical procedure.

Methods

The study population consisted of 1,029 patients with ischemic heart disease (IHD). We divided the study population into two groups (ACS and non-ACS) and by diseased vessels (organic stenosis). Covariance structure analysis was simultaneously performed in one equation model for determination and comparison of the risk factors for organic stenosis and ACS.

Results

The analysis revealed that age (standardized regression coefficient, β: 0.206, P < 0.001), male gender (β: 0.126, P < 0.001), HbA1c level (β: 0.109, P < 0.001), HDL level (β: -0.109, P < 0.001) and LDL level (β: 0.127, P = 0.002) were significant for the advancement of organic stenosis. HDL level (β: 0100, P = 0.002) and MDA-LDL level (β: 0.335, P < 0.001) were significant for the onset of ACS, but age, HbA1c and LDL (P = NS or β < 0.1, respectively) were not. Among the risk factors, age, HbA1c and LDL were significantly more strongly associated with organic stenosis than ACS, while MDA-LDL was significantly more strongly associated with ACS than organic stenosis.

Conclusions

The current statistical analysis revealed clear differences among the risk factors between the progression of organic stenosis and the onset of ACS. Among them, the MDA-LDL level should be considered to indicate a substantial risk of ACS.