N-terminal fragment of pro-brain natriuretic peptide (NT-proBNP) for predicting silent myocardial ischaemia in type 2 diabetes mellitus independent of microalbuminuria

Chronic kidney disease is a key predictive factor for potential myocardial ischaemia and poor prognosis in asymptomatic patients with diabetes mellitus

Some asymptomatic patients with diabetes mellitus (DM) have critical coronary artery disease (CAD), although the guidelines do not recommend aggressive screening for CAD in asymptomatic patients. Chronic kidney disease (CKD) is among the serious co-morbidities of severe systemic atherosclerosis. Thus, CKD may be associated with potential myocardial ischaemia. Therefore, the present study aimed to determine the impact of CKD on the incidence of silent myocardial ischaemia (SMI) and the long-term outcomes in asymptomatic patients with DM. This study investigated 461 consecutive patients with DM. All patients who were asymptomatic and self-sufficient in daily life underwent the ergometer exercise (ERG) test. Coronary angiography was performed if the stress test was positive, or if the patient did not achieve 90% of the target heart rate. The primary end point included major adverse cardiac and cerebrovascular events (MACCE) including death, non-fatal myocardial infarction and stroke. The median follow-up duration after study enrolment was 35 months for the entire cohort of 461 patients. Eighty-one patients were diagnosed with SMI. The estimated glomerular filtration rate was significantly lower in the SMI group (70.5 ± 23.8 vs. 81.8 ± 30.0 mL/min/1.73 m², P < 0.001). SMI occurred more frequently in patients with advanced CKD [27/103, (26.2%) in stages 3–5], whereas only 5/68 (7.3%) patients without CKD, 13/81 (16.0%) patients with stage 1 CKD and 36/209, (17.2%) in stage 2, had SMI. The Kaplan–Meier curves revealed that, patients with SMI had poor clinical outcomes (log-rank: P = 0.016). The incidence of MACCE (log-rank: P = 0.009) was higher in patients with severe CKD > stage 3a in the SMI subgroup. Urinary albumin (mg/gCr) was associated with MACCE in the SMI subgroup [HR 3.37, 95%CI (1.170–9.521), P = 0.025] after adjusting for age, sex, and conventional risk factors. SMI was more prevalent in patients with CKD and the incidence was proportional to the CKD stage in asymptomatic patients with DM. Those Patients with CKD and SMI exhibited poor clinical outcomes. CKD may be a key factor for the identification and management of SMI in asymptomatic patients with DM in routine clinical practice.

Trial Registration: UMIN000038340.

The role of natriuretic peptides in diabetes and its complications

This review aimed to summarize recent findings on the role of natriuretic peptides (NPs) in diabetes and its important complications. Although the treatment of diabetes mellitus has benefited from recent advances, aggressive glycemic control can increase the risk of hypoglycemia and weight gain. Therefore, innovative therapies are required to address this issue. Natriuretic peptides (NPs) may have such novel therapeutic potential. NPs comprise a family of structurally related peptides, including atrial, brain, C-type, and dendroaspis. Each of these NPs has a wide range of specific functions to regulate and maintain cardiovascular, renal, and endocrine homeostasis. NPs exert their effects by interacting with three receptor subtypes including NPR-A, NPR-B, and NPR-C. The coronary NP system has been suggested to be involved in regulating water and salt balance, as well as vascular remodeling. In this review, we provide evidence that NPs play an important role in diabetes mellitus and its related complications including macrovascular and microvascular disorders. NPs hold promise as markers for early diagnosis, risk assessment, and intervention guidance in diabetes and its complications and may thus improve diabetes care.

N-terminal fragment of probrain natriuretic peptide is associated with diabetes microvascular complications in type 2 diabetes

Aim/introduction

Circulating levels of N-terminal fragment of probrain natriuretic peptide (NT-proBNP) are established as a risk factor for cardiovascular disease and mortality in patients with diabetes, as well as in the general population. We sought to examine the possibility of NT-proBNP as a biomarker of microvascular complications in patients with type 2 diabetes.

Materials and methods

In total, 277 outpatients with type 2 diabetes were consecutively enrolled as a hospital cohort. Two hundred and seventeen of these patients (132 males; mean age, 63.4 years) were designated as cases with any of the diabetic complications (retinopathy, neuropathy, nephropathy, ischemic heart disease, strokes, peripheral artery disease), and 60 (42 males; mean age, 54.1 years) were set as controls without clinical evidence of diabetic complications. Diabetic complications were evaluated by medical record and routine laboratory examinations. NT-proBNP was measured and investigated with regard to the associations with diabetic complications.

Results

Mean NT-proBNP levels were significantly higher in patients with any of the diabetic complications (59 versus 33 pg/mL; P<0.0001). In logistic regression analysis, NT-proBNP levels >79 pg/mL, which was the highest tertile, were independently associated with a 5.04 fold increased risk of all complications (P<0.0051) compared to the lowest tertile (NT-proBNP levels <31 pg/mL). Odd ratios of cardiovascular disease and nephropathy, neuropathy, and retinopathy were 9.33, 6.23, 6.6 and 13.78 respectively, in patients with NT-proBNP values in the highest tertile (>79 pg/mL), independently of age, sex, duration of diabetes or other risk factors, such as body mass index or hemoglobin A_1c. In addition, NT-proBNP levels were associated with surrogate markers of atherosclerosis, such as brachial-ankle pulse wave velocity (r=0.449, P<0.0001) and left ventricular hypertrophy (r=0.212, P<0.001).

Conclusion

In this hospital-based cohort of type 2 diabetes, the NT-proBNP levels were associated with systemic atherosclerosis and comorbid diabetic microvascular as well as macrovascular complications. It is useful to stratify high-risk diabetic patients by measuring NT-proBNP and to start comprehensive care for preventing the progression of diabetic complications. It is necessary to elucidate the underlying mechanism for the progression of diabetic complications represented by an elevation of NT-proBNP and to demonstrate the ability of NT-proBNP as a predictive global biomarker for diabetic complications in Japanese type 2 diabetic patients.

Metformin treatment may be associated with decreased levels of NT-proBNP in patients with type 2 diabetes

PURPOSE

Individuals with type 2 diabetes (T2DM) are at increased risk of cardiovascular disease, including heart failure (HF). In patients with T2DM elevated serum concentrations of the N-terminal fragment of pro-B-type natriuretic peptide (NT-proBNP) correlate with cardiovascular morbidity and mortality. We aimed to identify predictors of increased serum NT-proBNP levels in patients with T2DM.

METHODS

The study included 185 patients with T2DM treated with either oral antidiabetic agents (49.7%) or insulin (17.8%), or both (32.5%). We divided the patients into two groups: with high (>200 pg/mL) and low (≤200 pg/mL) NT-proBNP concentrations.

RESULTS

We found differences between the patients with high and low NT-proBNP levels including age, prevalence of dyslipidemia and HF, history of previous myocardial infarction (MI), heart rate, hemoglobin level, platelet count, creatinine, urea and uric acid concentrations, use of beta-blockers, loop diuretics, metformin and insulin. In a multivariate analysis metformin was a negative predictor of increased NT-proBNP concentration. Age, history of HF and decreased estimated glomerular filtration rate (eGFR) were positive predictors. We found no correlation between NT-proBNP serum concentration and insulin treatment or history of coronary artery disease or MI.

CONCLUSION

Metformin correlates with lower concentrations of NT-proBNP in patients with T2DM.

Brain natriuretic hormone predicts stress-induced alterations in diastolic function

BACKGROUND

Mental stress (MS) reduces diastolic function (DF) and may lead to congestive heart failure with preserved systolic function. Whether brain natriuretic hormone (brain natriuretic peptide [BNP]) mediates the relationship of MS with DF is unknown.

METHODS

One hundred sixty individuals aged 30 to 50 years underwent 2-hour protocol of 40-minute rest, videogame stressor and recovery. Hemodynamics, pro-BNP samples and DF indices were obtained throughout the protocol. Separate regression analyses were conducted using rest and stress E/A, E' and E/E' as dependent variables. Predictor variables were entered into the stepwise regression models in a hierarchical fashion. At the first level, age, sex, race, height, body mass index, pro-BNP and left ventricular mass (LVM) were permitted to enter the models. The second level consisted of systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR). The final level contained cross-product terms of race by SBP, DBP and HR.

RESULTS

E/A ratio was lower during stress compared to rest and recovery (P < 0.01). Resting E/A ratio was predicted by a regression model of age (-0.31), pro-BNP (0.16), HR (-0.40) and DBP (-0.23) with an R² = 0.33. Stress E/A ratio was predicted by age (-0.24), pro-BNP (0.08), HR (-0.38) and SBP (-0.21) with total R² = 0.22. Resting E' model consisted of age (-0.22), pro-BNP (0.26), DBP (-0.27) and LVM (-0.15) with an R² = 0.29. Stress E' was predicted by age (-0.18), pro-BNP (0.35) and LVM (-0.18) with an R² = 0.18. Resting E/E' was predicted by race (0.17, B > W) and DBP (0.24) with an R² = 0.10. Stress E/E' consisted of pro-BNP (-0.36), height (-0.26) and HR (-0.21) with an R² = 0.15.

CONCLUSIONS

pro-BNP predicts both resting and stress DF, suggesting that lower BNP during MS may be a marker of diastolic dysfunction in apparently healthy individuals.

Correlation between arterial wall stiffness, N-terminal prohormone of brain natriuretic peptide, functional and structural myocardial abnormalities in patients with type 2 diabetes mellitus and cardiac autonomic neuropathy

Aim. To assess arterial wall stiffness, plasma levels of of N-terminal prohormone of brain natriuretic peptide (NT-proBNP), as well as functional state and structure of the myocardium in patients with type 2 diabetes mellitus (T2DM) and cardiac autonomic neuropathy (CAN). Materials and Methods. The study involved a total of 65 patients with T2DM. 12 had no evidence of cardiovascular disease (CVD) or CAN, 14 were diagnosed with subclinical stage of CAN, 18 ? with functional stage, and 21 ? with organic stage. We measured aortic pulse wave velocity (PWV), aortic augmentation index (AIx), brachial artery AIx, ambulatory arterial stiffness index (AASI) and plasma levels of NT-proBNP. Clinical examination included ECG, Holter monitoring, ambulatory BP measurement and echocardiography. Results.  Patients with isolated T2DM showed a trend for increased vascular wall stiffness. PWV was increased in patients with subclinical stage of CAN. Aortic and brachial AIx, PWV and AASI were elevated in patients with functional stage of CAN, PWV being significantly higher vs. subclinical CAN subgroup. Organic stage was characterized by pathologically increased values of all primary parameters; PWV and AASI were significantly higher compared with other groups. Development and progression of CAN was accompanied by an increase in NT-proBNP plasma levels. Concentration of NT-proBNP was in direct correlation with left ventricular mass (LVM) and PWV. PWV and LVM values also directly correlated between themselves. Conclusion. Development and progression of CAN in patients with T2DM is accompanied by an increase in vascular wall stiffness. The elevation of plasma NT-proBNP in patients with T2DM correlates with the development of CAN and is significantly and independently associated with an increase in LVM and PWV. Our data suggests the pathophysiological interconnection between metabolic, functional and structural myocardial abnormalities in patients with T2DM and CAN.

Does the relationship between natriuretic hormones and diastolic function differ by race?

INTRODUCTION

Heart failure develops earlier and is more prevalent in blacks than whites because of their higher incidence of hypertension and diabetes and likely subsequent diastolic dysfunction. Natriuretic peptides (NP) prevent cardiac malfunction through pressure, natriuresis action. However, whether race affects the relationships of NP action with cardiac function is unknown.

METHODS

To assess this, 55 (21 whites and 27 males) normotensive adults underwent a 2-hour protocol of 40 minutes rest, video game stressor and recovery. Mitral inflow and myocardial velocities (tissue Doppler) were recorded every 20 minutes. Blood pressure and heart rate were obtained at 10-minute intervals. Blood samples for pro-atrial NP and pro-brain NP (pro-BNP) were collected every 40 minutes.

RESULTS

There were differences in the association between (1) the changes from rest to stress for E/A ratio and double product (whites, r = -0.42; blacks, r = 0. 10; P = 0.034 for difference between correlations); (2) stress E(m) and pro-atrial NP (whites, r = 0.59; blacks, r = -0.25; P = 0.025); (3) rest E(m) and BNP (whites, r = 0.83; blacks r = -0.17; P = 000); (4) rest E(m)/A(m) and pro-BNP (whites, r = 0.70; blacks, r = -0.42; P = 0.003); (5) rest E/E(m) and pro-BNP (whites, r = -0.61; blacks, r = 0.31; P = 0.015) and (6) stress E and pro-BNP (whites, r = 0.56; blacks, r = -0.18; P = 0.043).

CONCLUSION

The higher correlations between levels of NP and diastolic function indices both at rest and stress suggest that NP protective action is more pronounced in whites than in blacks.

Predictive value of serum NT-proBNP levels in type 2 diabetic people with diabetic nephropathy

OBJECTIVE

The serum N-terminal fragment of pro brain natriuretic peptide (NT-proBNP) level in type 2 diabetic subjects with or without diabetic nephropathy (DN) is still unclear. We aimed to evaluate the relationship between serum NT-proBNP levels and different stages of diabetic nephropathy, and identify probable factors predicting serum NT-proBNP level.

SUBJECTS AND METHODS

This cross-sectional study included 20 normoalbuminuric (Group-I), 28 microalbuminuric (Group-II), 20 macroalbuminuric type 2 diabetic patients (Group-III), and 20 healthy volunteers (Group-IV). Serum NT-proBNP levels were measured with highly sensitive and specific immunoassay.

RESULTS

Mean NT-proBNP levels were 32 ± 55, 91 ± 95, 331 ± 297, 42 ± 34 pg/ml for Groups I-IV, respectively. When patients with LVH were excluded, mean logNT-proBNP was still significantly higher in Group-III than all other groups. The three diabetic groups were similar in age, BMI, HbA1c, fasting serum glucose, and GFR. In a multivariate linear regression model, adjusting for factors significantly correlated with NT-proBNP levels, the patient group, presence of LVH, and hemoglobin remained as an independent predictor of serum NT-proBNP. These variables explained 68% of the variability of NT-proBNP (adjusted R(2)=0.683).

CONCLUSIONS

Mean serum NT-proBNP level of macroalbuminuric diabetic patients was higher than normoalbuminuric and microalbuminuric diabetic patients, and healthy control subjects even after exclusion of LVH. NT-proBNP may be a useful and predictive marker of diabetic nephropathy.