Impact of oxidative stress on myocardial performance in patients with diabetes: a focus on subclinical left ventricular dysfunction

INTRODUCTION

Oxidative stress is known to affect left ventricular functions negatively. There is a strong bidirectional connection between diabetes mellitus (DM) and oxidative stress. In parallel, left ventricular dysfunction is observed more frequently, even in patients with DM without other risk factors. In this context, the objective of this study is to comparatively investigate the potential relationship between oxidative stress and subclinical left ventricular dysfunction (SCLVD) assessed by Myocardial Performance Index (MPI) in patients with and without DM.

RESEARCH DESIGN AND METHODS

The sample of this observational cross-sectional single-center study consisted of 151 patients who were evaluated for oxidative stress and SCLVD by tissue Doppler echocardiography. Patients' total oxidant status (TOS), total antioxidant status (TAS), and Oxidative Stress Index (OSI) values were calculated. The effects of oxidative stress and DM on MPI were analyzed.

RESULTS

There were 81 patients with DM (mean age: 46.17±10.33 years) and 70 healthy individuals (mean age: 45.72±9.04 years). Mean TOS and OSI values of the DM group were higher than healthy individuals (5.72±0.55 vs 5.31±0.50, p = <0.001; and 4.92±1.93 vs 1.79±0.39, p = <0.001; respectively). The mean TAS value of the DM group was significantly lower than the healthy group (1.21±0.40 vs 3.23±0.51, p = <0.001). There was a significant correlation between OSI and MPI mitral in the DM group (R 0.554, p = <0.001) but not in the healthy group (R -0.069, p=0.249).

CONCLUSIONS

Both oxidative stress and myocardial dysfunction were found to be more common in patients with DM. The study's findings indicated the negative effect of oxidative stress on myocardial functions. Accordingly, increased oxidative stress caused more significant deterioration in MPI in patients with DM compared with healthy individuals.

Prevalence of Chronic Diabetic Complications in Newly Diagnosed versus Known Type 2 Diabetic Subjects in a Sample of Alexandria Population, Egypt

BACKGROUND

In Egypt, data on the prevalence of chronic diabetic complications, which are essential for the adjustment of policies and practices related to diabetes care, are scarce. Therefore, the aim of this study was to determine the frequency of chronic complications of diabetes; namely neuropathy, Diabetic Kidney Disease (DKD), retinopathy and Peripheral Arterial Disease (PAD) in newly-diagnosed versus known type 2 diabetic patients.

SUBJECTS & METHODS

This is a cross-sectional study that is based on a previous household survey conducted on a representative sample of the population of Alexandria, Egypt. This study included 506 consecutive subjects with type 2 diabetes; 323 patients with previously known T2DM and 183 patients with newly diagnosed T2DM (discovered during the survey). For each participant, a focused history was taken. Comprehensive clinical examination was done including fundus examination, foot examination and assessment of ankle brachial index. Laboratory tests included HbAlc, lipids profile, serum creatinine and Urinary Albumin Creatinine Ratio (UACR).

RESULTS

Peripheral neuropathy was detected in 20% of the studied patients; 29.4% of known patients and 3.3% of newly diagnosed patients (p<0.001). Diabetic kidney disease was detected in 33.2% of the studied patients; 46.1% of known patients and 10.4% of newly diagnosed patients (p<0.001). Diabetic retinopathy was detected in 34.6% of the studied patients; 48.3% of known patients and 10.4% of newly diagnosed patients (p<0.001). Peripheral arterial disease was detected in 32.6% of the studied patients; 45.5% of known patients and 9.8% of newly diagnosed patients (p<0.001). In patients with known diabetes, the presence of any of the studied complications (neuropathy, diabetic kidney disease, retinopathy or PAD) was significantly associated with the presence of all other complications (p< 0.001). In patients with newly-diagnosed diabetes, the presence of diabetic kidney disease was significantly associated with the presence of retinopathy (p<0.001), with no significant association with PAD (p=0.357).

CONCLUSION

The present study confirms that a considerable proportion of people with T2DM have microvascular complications and/or PAD at the time of, and possibly years before, diagnosis. Having shown that, it is strongly recommended to apply appropriate screening strategies for subjects with diabetes at the time of diagnosis. Finally, these results should be considered as a call for action for the health care planners and providers in our region to plan for early screening for diabetes and its complications to reduce the disease burden in our community.

Type 2 diabetes mellitus-related changes in left ventricular structure and function in patients with chronic kidney disease

Type 2 Diabetes mellitus (DM) is the leading cause of chronic kidney disease (CKD) worldwide, and is associated with an increased risk of left ventricular (LV) hypertrophy, LV systolic and diastolic dysfunctions. The aim of this study was to investigate abnormal echocardiographic findings in patients with CKD with and without DM, and identify the factors associated with these abnormalities. We enrolled 356 pre-dialysis patients with CKD (stages 3-5), including 208 with DM and 148 without DM. The structure and systolic and diastolic functions of the left ventricle were assessed using echocardiography, and the clinical and echocardiographic parameters were analyzed. The patients with DM had higher rates of observed/predicted left ventricular mass > 128% (69.5% vs. 56.7%, p = 0.015), midwall fractional shortening < 14% (22.6% vs. 8.8%, p = 0.001), and ratio of peak early transmitral filling wave velocity to early diastolic velocity of lateral mitral annulus > 12 (32.7% vs. 16.2%, p < 0.001) than those without DM. Multivariate analysis showed that male sex, a history of smoking, high systolic blood pressure, high body mass index, high levels of fasting glucose and total cholesterol, low levels of albumin and hemoglobin, and a low estimated glomerular filtration rate were associated with abnormal echocardiographic findings. The rates of inappropriate left ventricular mass, systolic and diastolic dysfunction were higher in our patients with CKD and DM than in those without DM.

Strategy to identify subjects with diabetes mellitus more suitable for selective echocardiographic screening: The DAVID-Berg study

BACKGROUND

Despite the burden of pre-clinical heart failure (HF) among diabetes mellitus (DM) patients, routine screening echocardiography is not currently recommended. We prospectively assessed risk prediction for HF/death of a screening strategy combining clinical data, electrocardiogram, NTproBNP, and echocardiogram, aiming to identify DM patients more suitable for selective echocardiography.

METHODS

Among 4047 screened subjects aged≥55/≤80years, the DAVID-Berg Study prospectively enrolled 623 outpatients with DM, or hypertension, or known cardiovascular disease but with no HF history/symptoms. The present analysis focuses on data obtained during a longitudinal follow-up of the 219 patients with DM.

RESULTS

Mean age was 68years, 61% were men, and median DM duration was 4.9years. During a median follow-up of 5.2years, 50 subjects developed HF or died. A predictive model using clinical data demonstrated moderate predictive power, which significantly improved by adding electrocardiogram (C-statistic 0.75 versus 0.70; p<0.05), but not NTproBNP (C-statistic 0.72, p=0.20). Subjects with normal clinical variables or abnormal clinical variables but normal electrocardiogram had low events rate (1.3 versus 2.4events/100-person-years, p=NS). Conversely, subjects with both clinical and electrocardiogram abnormalities (47%) carried higher risk (9.0events/100-person-years, p<0.001). The predictive power for mortality/HF development increased when echocardiography was added (13.6events/100-person-years, C-statistic 0.80, p<0.05).

CONCLUSIONS

Our prospective study found that a selective echocardiographic screening strategy guided by abnormal clinical/electrocardiogram data can reliably identify DM subjects at higher risk for incident HF and death. This screening approach may hold promise in guiding HF prevention efforts among DM patients.

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.

Prevalence, types and factors associated with echocardiographic abnormalities among newly diagnosed diabetic patients at Mulago Hospital

BACKGROUND

The prevalence of Diabetes mellitus (DM) is on a rise in sub-Saharan Africa and will more than double by 2025. Cardiovascular disease (CVD) accounts for up to 2/3 of all deaths in the diabetic population. Of all the CVD deaths in DM, 3/4 occur in sub Saharan Africa (SSA). Non invasive identification of cardiac abnormalities, such as Left Ventricular Hypertrophy (LVH), diastolic and systolic dysfunction, is not part of diabetes complications surveillance programs in Uganda and there is limited data on this problem. This study sought to determine the prevalence, types and factors associated with echocardiographic abnormalities among newly diagnosed diabetic patients at Mulago National referral hospital in Uganda.

METHODS

In this cross sectional study conducted between June 2014 and December 2014, we recruited 202 newly diagnosed adult diabetic patients. Information on patients' socio-demographics, bio-physical profile, biochemical testing and echocardiographic findings was obtained for all the participants using a pre-tested questionnaire. An abnormal echocardiogram in this study was defined as the presence of LVH, diastolic and/or systolic dysfunction and wall motion abnormality. Bivariate and multivariate logistic regression analyses were used to investigate the association of several parameters with echocardiographic abnormalities.

RESULTS

Of the 202 patients recruited, males were 102(50.5%) and the mean age was 46±15 years. Majority of patients had type 2 DM, 156(77.2%) and type 1 DM, 41(20.3%) with mean HbA1C of 13.9±5.3%. Mean duration of diabetes was 2 months. The prevalence of an abnormal echocardiogram was 67.8 % (95% CI 60%-74%). Diastolic dysfunction, systolic dysfunction, LVH and wall motion abnormalities were present in 55.0%, 21.8%, 19.3% and 4.0% of all the participants respectively. In bivariate logistic regression analysis, the factors associated with an abnormal echocardiogram were age (OR 1.09 [95% CI 1.06-1.12], P <0.0001), type 2 DM (OR 5.8[95% CI 2.77-12.07], P<0.0001), hypertension (OR 2.64[95% CI 1.44-4.85], P=0.002), obesity (OR 3.51[955 CI 1.25-9.84], P=0.017 and increased waist circumference (OR 1.02[95% CI 1.00-1.04], P=0.024. On Multiple logistic regression analysis, age was the only factor associated with an abnormal echocardiogram (OR 1.09[95%CI 1.05-1.15], P<0.0001).

CONCLUSION

Echocardiographic abnormalities were common among newly diagnosed adults with DM. Traditional CVD risk factors were associated with an abnormal echocardiogram in this patient population. Due to a high prevalence of echocardiographic abnormalities among newly diagnosed diabetics, we recommend screening for cardiac disease especially in patients who present with traditional CVD risk factors. This will facilitate early diagnosis, management and hence better patient outcomes.

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

BACKGROUND

In the early identification of cardiovascular risk, it is essential to establish a biological marker for cardiac complications that is comparable to albuminuria for nephropathy. We tested the hypothesis that N-terminal pro-brain natriuretic peptide (NT-proBNP) might be a marker for silent myocardial ischaemia in diabetes.

METHODS

In forty consecutively recruited subjects without evident coronary artery disease, serum NT-proBNP was measured together with multi-slice computed tomography. With patients suspected of having significant coronary artery stenosis by multi-slice computed tomography, coronary angiography was performed. Silent myocardial ischaemia was defined as the presence of significant coronary artery stenosis with more than 50% luminal narrowing by angiography.

RESULTS

Thirteen patients (32.5%) had silent myocardial ischaemia. NT-proBNP levels were significantly higher in these patients (181.1 ± 43.8 versus 55.2 ± 9.7 pg/mL, p < 0.005) but HbA(1c), lipid profiles, and creatinine were similar in the two groups. Moreover, log NT-proBNP was identified as an independent predictor of silent myocardial ischaemia (R(2) = 0.502, p < 0.05) after adjustment for HbA(1c), creatinine, albuminuria, hypertension, hyperlipidaemia, or smoking. After stratifying patients by NT-proBNP, the upper tertile compared to the lowest tertile was significantly associated with silent myocardial ischaemia (odds ratio: 26.7, p < 0.05). Receiver operation characteristics analysis with a cut-off value of 52 pg/mL showed 92% sensitivity and 75% specificity for predicting silent myocardial ischaemia (positive predictive value 64.7%, negative predictive value 94.3%).

CONCLUSIONS

The outstandingly high negative predictive value of NT-proBNP enables us to focus on diabetic patients with occult coronary disease, independently of microalbuminuria.

[Combined antihypertensive and antilipemic therapy as one of the pillars in the poly-pharmacologic preventive strategy for patients with high cardiovascular risk]

Hypertension is a highly prevalent disease and a strong risk factor for cardiovascular disease in industrialized countries in Europe and North America. About 40-50% of hypertensive patients have some other cardiovascular risk factors as smoking, dyslipidemia, glucose intolerance, metabolic syndrome and diabetes. The realization of optimal therapy of these patients is a difficult task, and reaching target blood pressure values is almost impossible by monotherapy. It was realized that the simultaneous normalization of blood pressure and that of abnormal lipid profile with 2-3 or more drugs have great importance for preventing atherosclerotic complications.We started an open-formed study with about 1000 hypertensive patients complicated with dyslipidemia, visceral obesity, metabolic syndrome and diabetes type 2. The base of our therapeutic strategy was a typical poly-pharmacologic treatment with ACE inhibitor (lisinopril), calcium antagonist (amlodipine), statin (atorvastatin) and antiplatelet therapy (if it was necessary).