Progression of cardiovascular autonomic neuropathy and cardiovascular disease in type 2 diabetes. Cardiovasc Diabetol. 2018;17:109. [PMID: 30071872 PMCID: PMC6071370 DOI: 10.1186/s12933-018-0752-6]

Cardiovascular autonomic neuropathy is associated with SLEDAI in patients with systemic lupus erythematosus

INTRODUCTION

As a prevalent and severe complication of systemic lupus erythematosus (SLE), cardiovascular autonomic neuropathy (CAN) has garnered increasing attention. Reports suggested that CAN may be related to the disease activity of SLE. This study aims to explore whether Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) is associated with CAN and to evaluate its diagnostic value for CAN.

METHOD

Altogether, 144 patients with SLE from the Rheumatology Department of Nanjing Drum Tower Hospital were included. Each patient underwent assessment with the SLEDAI and cardiovascular reflex tests (CARTs). Patients were classified into three groups: non-CAN, early-CAN and diagnosed-CAN based on the CARTs results. The relationship of CARTs and SLEDAI were analyzed using SPSS 26.0.

RESULTS

After being divided into three groups, there were significant differences in SLEDAI among them. With increasing SLEDAI score (P < 0.05), both CARTs scores and four individual parameters score increased significantly, both before and after adjusting for influencing factors (P < 0.05). Besides, in Logistic regression analysis, it identified that SLEDAI as an independent risk factor for CAN (OR = 1.227, 95%CI = 1.143-1.316, P < 0.001). Finally, after accounting for the influence of glucocorticoids, a significant positive correlation between CARTs and SLEDAI remained (P < 0.05).

CONCLUSIONS

As the gold standard in the diagnosing CAN, CARTs and four parameters are significantly correlated with SLEDAI. Furthermore, SLEDAI is also an independent risk factors for its development. In conclusion, this research demonstrated that SLEDAI is a dependable indicator for the onset and progression of CAN. Key Points • This study is the first to demonstrate a strong association between SLEDAI and cardiovascular autonomic neuropathy, identifying SLEDAI as a risk factor for CAN in SLE patients. • This study offers a convenient and rapid method for the clinical evaluation of CAN in SLE patients, providing significant value in assessing cardiovascular complications.

Diabetic kidney disease and cardiac autonomic neuropathy: insights on exercise rehabilitation

Patients with Diabetic Kidney Disease (DKD) suffer from various complications of diabetes mellitus, including autonomic neuropathy. Cardiac autonomic nervous system dysfunction is a common disorder in patients with diabetes mellitus and Chronic Kidney Disease (CKD), and is associated with an increased risk of arrhythmias and cardiovascular morbidity and mortality. Although the effects of exercise training have been thoroughly studied in different patient populations with CKD or diabetes mellitus, few studies have investigated the effects of exercise on cardiac autonomic nervous system activity in patients with DKD. This narrative review aims to summarize the evidence regarding the effects of exercise training on cardiac autonomic nervous system modulation in DKD patients.

Links Between Obstructive Sleep Apnea and Myocardial Blood Flow Changes Impacting Adverse Cardiovascular Disease-related Outcomes

PURPOSE OF REVIEW

Recent studies have demonstrated an association between obstructive sleep apnea (OSA) and abnormal myocardial blood flow (MBF), myocardial flow reserve (MFR), and coronary microvascular dysfunction (CMD). Here, we review the evidence and describe the potential underlying mechanisms linking OSA to abnormal MBF. Examining relevant studies, we assess the impact of OSA-specific therapy, such as continuous positive airway pressure (CPAP), on MBF.

RECENT FINDINGS

Recent studies suggest an association between moderate to severe OSA and abnormal MBF/MFR. OSA promotes functional and structural abnormalities of the coronary microcirculation. OSA also promotes the uncoupling of MBF to cardiac work. In a handful of studies with small sample sizes, CPAP therapy improved MBF/MFR. Moderate to severe OSA is associated with abnormal MFR, suggesting an association with CMD. Evidence suggests that CPAP therapy improves MBF. Future studies must determine the clinical impact of improved MBF with CPAP.

Precision prognostics for cardiovascular disease in Type 2 diabetes: a systematic review and meta-analysis

BACKGROUND

Precision medicine has the potential to improve cardiovascular disease (CVD) risk prediction in individuals with Type 2 diabetes (T2D).

METHODS

We conducted a systematic review and meta-analysis of longitudinal studies to identify potentially novel prognostic factors that may improve CVD risk prediction in T2D. Out of 9380 studies identified, 416 studies met inclusion criteria. Outcomes were reported for 321 biomarker studies, 48 genetic marker studies, and 47 risk score/model studies.

RESULTS

Out of all evaluated biomarkers, only 13 showed improvement in prediction performance. Results of pooled meta-analyses, non-pooled analyses, and assessments of improvement in prediction performance and risk of bias, yielded the highest predictive utility for N-terminal pro b-type natriuretic peptide (NT-proBNP) (high-evidence), troponin-T (TnT) (moderate-evidence), triglyceride-glucose (TyG) index (moderate-evidence), Genetic Risk Score for Coronary Heart Disease (GRS-CHD) (moderate-evidence); moderate predictive utility for coronary computed tomography angiography (low-evidence), single-photon emission computed tomography (low-evidence), pulse wave velocity (moderate-evidence); and low predictive utility for C-reactive protein (moderate-evidence), coronary artery calcium score (low-evidence), galectin-3 (low-evidence), troponin-I (low-evidence), carotid plaque (low-evidence), and growth differentiation factor-15 (low-evidence). Risk scores showed modest discrimination, with lower performance in populations different from the original development cohort.

CONCLUSIONS

Despite high interest in this topic, very few studies conducted rigorous analyses to demonstrate incremental predictive utility beyond established CVD risk factors for T2D. The most promising markers identified were NT-proBNP, TnT, TyG and GRS-CHD, with the highest strength of evidence for NT-proBNP. Further research is needed to determine their clinical utility in risk stratification and management of CVD in T2D.

Cardiac Autonomic Dysfunction and Risk of Silent Myocardial Infarction Among Adults With Type 2 Diabetes

Background There is a paucity of large-scale epidemiological studies on the link between cardiac autonomic neuropathy (CAN) and the risk of silent myocardial infarction (SMI) in type 2 diabetes. We evaluated the association between CAN and the risk of SMI in a large sample of adults with type 2 diabetes. Methods and Results Participants with type 2 diabetes from the ACCORD (Action to Control Cardiovascular Risk in Diabetes) study without atherosclerotic cardiovascular disease at baseline were included. CAN was ascertained using heart rate variability indices calculated from 10-s resting electrocardiograms. The heart rate variability indices included standard deviation of all normal-to-normal R-R intervals and root mean square of successive differences between normal-to-normal R-R intervals. CAN was defined as both the standard deviation of all normal-to-normal R-R intervals and root mean square of successive differences between normal-to-normal R-R intervals less than the fifth percentile of the general population. We used Cox proportional hazards regression to generate hazard ratios (HRs) for incident SMI in relation to CAN measures. Among 4842 participants (mean age, 62.5 years; 46.6% women; 60.2% White), there were 73 incident SMI cases over a median follow-up of 4.9 years (incidence rate 3.1 out of 1000 person-years [95% CI, 2.5-3.9]). After adjusting for confounders, low heart rate variability was associated with a higher risk of SMI (HR, 1.67 [95% CI, 1.02-2.72] and HR, 1.56 [95% CI, 0.94-2.58] for low standard deviation of all normal-to-normal R-R intervals and root mean square of successive differences between normal-to-normal R-R intervals, respectively). Participants with CAN had a 1.9-fold greater risk of SMI (HR, 1.91 [95% CI, 1.14-3.20]). Conclusions In a large cohort of adults with type 2 diabetes, CAN was significantly associated with an increased risk of incident SMI.

Precision Prognostics for Cardiovascular Disease in Type 2 Diabetes: A Systematic Review and Meta-analysis

Background Precision medicine has the potential to improve cardiovascular disease (CVD) risk prediction in individuals with type 2 diabetes (T2D). Methods We conducted a systematic review and meta-analysis of longitudinal studies to identify potentially novel prognostic factors that may improve CVD risk prediction in T2D. Out of 9380 studies identified, 416 studies met inclusion criteria. Outcomes were reported for 321 biomarker studies, 48 genetic marker studies, and 47 risk score/model studies. Results Out of all evaluated biomarkers, only 13 showed improvement in prediction performance. Results of pooled meta-analyses, non-pooled analyses, and assessments of improvement in prediction performance and risk of bias, yielded the highest predictive utility for N-terminal pro b-type natriuretic peptide (NT-proBNP) (high-evidence), troponin-T (TnT) (moderate-evidence), triglyceride-glucose (TyG) index (moderate-evidence), Genetic Risk Score for Coronary Heart Disease (GRS-CHD) (moderate-evidence); moderate predictive utility for coronary computed tomography angiography (low-evidence), single-photon emission computed tomography (low-evidence), pulse wave velocity (moderate-evidence); and low predictive utility for C-reactive protein (moderate-evidence), coronary artery calcium score (low-evidence), galectin-3 (low-evidence), troponin-I (low-evidence), carotid plaque (low-evidence), and growth differentiation factor-15 (low-evidence). Risk scores showed modest discrimination, with lower performance in populations different from the original development cohort. Conclusions Despite high interest in this topic, very few studies conducted rigorous analyses to demonstrate incremental predictive utility beyond established CVD risk factors for T2D. The most promising markers identified were NT-proBNP, TnT, TyG and GRS-CHD, with the highest strength of evidence for NT-proBNP. Further research is needed to determine their clinical utility in risk stratification and management of CVD in T2D.

Autonomic dysfunction and risk of severe hypoglycemia among individuals with type 2 diabetes

There are limited data on the link between cardiac autonomic neuropathy (CAN) and severe hypoglycemia in type 2 diabetes. Here, we evaluated the associations of CAN with severe hypoglycemia among 7,421 adults with type 2 diabetes from the Action to Control Cardiovascular Risk in Diabetes study. CAN was defined using ECG-derived measures. Cox's and Andersen-Gill regression models were used to generate HRs (HRs) for the first and recurrent severe hypoglycemic episodes, respectively. Over 4.7 years, there were 558 first and 811 recurrent hypoglycemic events. Participants with CAN had increased risks of a first episode or recurrent episodes of severe hypoglycemia. The intensity of glycemic management modified the CAN association with hypoglycemia. In the standard glycemic management group, compared with those of participants without CAN, HRs for a first severe hypoglycemia event and recurrent hypoglycemia were 1.58 and 1.96, respectively. In the intensive glycemic management group, HRs for a first severe hypoglycemia event and recurrent hypoglycemia were 1.10 and 1.24, respectively. In summary, CAN was independently associated with higher risks of a first hypoglycemia event and recurrent hypoglycemia among adults with type 2 diabetes, with the highest risk observed among those on standard glycemic management.

Cardiac autonomic dysfunction and risk of incident stroke among adults with type 2 diabetes

Introduction:

There is a dearth of data on the association between cardiac autonomic neuropathy (CAN) with incident stroke among individuals with diabetes mellitus. We evaluated this association in a large sample of adults with type 2 diabetes.

Patients and methods:

Participants with type 2 diabetes from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study without atherosclerotic cardiovascular disease at baseline were included. CAN was assessed at baseline by heart rate variability (HRV) indices and QT index (QTI) calculated from 10-s resting electrocardiograms. HRV was assessed using standard deviation of all normal-to-normal R-Rs intervals (SDNN) and root mean square of successive differences between normal-to-normal R-R intervals (rMSSD). CAN was defined based on several composite measures of SDNN, QTI, resting heart rate and peripheral neuropathy. We used Cox proportional hazards regression to generate hazard ratios (HR) and 95% confidence intervals (CI) for incident stroke in relation to CAN.

Results:

A total of 3493 participants (mean age 62.2 years, 44.5% women, 62.9% White) were included. Over a median follow-up of 5.0 years, 50 stroke cases occurred (incidence rate 3.0/1000 person-years [95% CI 2.2–3.9]). After adjusting for confounders, low HRV was associated with a higher risk of stroke (HR of 2.20 [95% CI 1.23–3.93] and 1.88 [95% CI 1.04–3.41] for low SDNN and rMSSD, respectively). Participants with CAN (defined as lowest quartile of SDNN and highest quartiles of QTI and heart rate) had a 5.7-fold greater risk of stroke (HR 5.70, 95% CI 2.49–13.08).

Discussion and conclusion:

CAN was independently associated with an increased risk of incident stroke in a large cohort of adults with type 2 diabetes.

Pathophysiological and clinical aspects of the circadian rhythm of arterial stiffness in diabetes mellitus: A minireview

Several cross-sectional trials have revealed increased arterial stiffness connected with the cardiac autonomic neuropathy in types 2 and 1 diabetic patients. The pathophysiological relationship between arterial stiffness and autonomic dysfunction in diabetes mellitus is still underinvestigated and the question whether the presence of cardiac autonomic neuropathy leads to arterial stiffening or increased arterial stiffness induced autonomic nervous system impairment is still open. Both arterial stiffness and dysfunction of the autonomic nervous system have common pathogenetic pathways, counting state of the chronic hyperinsulinemia and hyperglycemia, increased formation of advanced glycation end products, activation of protein kinase C, development of endothelial dysfunction, and chronic low-grade inflammation. Baroreceptor dysfunction is thought to be one of the possible reasons for the arterial wall stiffening development and progression. On the contrary, violated autonomic nervous system function can affect the vascular tone and by this way alter the large arteries walls elastic properties. Another possible mechanism of attachment and/or development of arterial stiffness is the increased heart rate and autonomic dysfunction corresponding progression. This minireview analyzes the current state of the relationship between the diabetes mellitus and the arterial stiffness. Particular attention is paid to the analysis, interpretation, and application of the results obtained in patients with type 2 diabetes mellitus and diabetic cardiac autonomic neuropathy.

Preferential impairment of parasympathetic autonomic function in type 2 diabetes

OBJECTIVE

Cardiovascular autonomic neuropathy is a known complication in type 2 diabetes (T2D). However, the extent of sympathetic dysfunction and its relation to blood pressure (BP) dysregulation is insufficiently studied. We therefore assessed the cardiovascular sympathetic function using a standardized autonomic test-battery.

RESEARCH DESIGN AND METHODS

Forty T2D patients (mean age and duration of diabetes ±SD, 65.5 ± 7.3 and 9.5 ± 4.2 years) and 40 age- and gender-matched controls were examined through autonomic testing, assessing cardiovascular responses to deep breathing, Valsalva maneuver and tilt-table testing. Additionally, 24-hour oscillometric BP and self-reported autonomic symptoms on COMPASS-31 questionnaire was recorded.

RESULTS

Patients with T2D had reduced parasympathetic activity with reduced deep breathing inspiratory:expiratory-ratio (median [IQR] T2D 1.11 [1.08-1.18] vs. controls 1.18 [1.11-1.25] (p = 0.01)), and reduced heart rate variability (p < 0.05). We found no differences in cardiovascular sympathetic function measured through BP responses during the Valsalva maneuver (p > 0.05). 24-hour-BP detected reduced night-time systolic BP drop in T2D (9.8 % ± 8.8 vs. controls 15.8 % ± 7.7 (p < 0.01)) with more patients having reverse dipping. Patients with T2D reported more symptoms of orthostatic intolerance on the COMPASS-31 (p = 0.04).

CONCLUSIONS

Patients with T2D showed reduced parasympathetic activity but preserved short-term cardiovascular sympathetic function, compared to controls, indicating autonomic dysfunction with predominantly parasympathetic impairment. Despite this, T2D patients reported more symptoms of orthostatic intolerance in COMPASS-31 and had reduced nocturnal BP dipping, indicating that these are not a consequence of cardiovascular sympathetic dysfunction.

Targeting autonomic nervous system as a biomarker of well-ageing in the prevention of stroke

Stroke prediction is a key health issue for preventive medicine. Atrial fibrillation (AF) detection is well established and the importance of obstructive sleep apneas (OSA) has emerged in recent years. Although autonomic nervous system (ANS) appears strongly implicated in stroke occurrence, this factor is more rarely considered. However, the consequences of decreased parasympathetic activity explored in large cohort studies through measurement of ANS activity indicate that an ability to improve its activity level and equilibrium may prevent stroke. In support of these observations, a compensatory neurostimulation has already proved beneficial on endothelium function. The available data on stroke predictions from ANS is based on many long-term stroke cohorts. These data underline the need of repeated ANS evaluation for the general population, in a medical environment, and remotely by emerging telemedicine digital tools. This would help uncovering the reasons behind the ANS imbalance that would need to be medically adjusted to decrease the risk of stroke. This ANS unbalance help to draw attention on clinical or non-clinical evidence, disclosing the vascular risk, as ANS activity integrates the cumulated risk from many factors of which most are modifiable, such as metabolic inadaptation in diabetes and obesity, sleep ventilatory disorders, hypertension, inflammation, and lack of physical activity. Treating these factors may determine ANS recovery through the appropriate management of these conditions. Natural aging also decreases ANS activity. ANS recovery will decrease global circulating inflammation, which will reinforce endothelial function and thus protect the vessels and the associated organs. ANS is the whistle-blower of vascular risk and the actor of vascular health. Such as, ANS should be regularly checked to help draw attention on vascular risk and help follow the improvements in response to our interventions. While today prediction of stroke relies on classical cardiovascular risk factors, adding autonomic biomarkers as HRV parameters may significantly increase the prediction of stroke.

Advances and Challenges in Biomarkers Use for Coronary Microvascular Dysfunction: From Bench to Clinical Practice

Coronary microvascular dysfunction (CMD) is related to a broad variety of clinical scenarios in which cardiac microvasculature is morphologically and functionally affected, and it is associated with impaired responses to vasoactive stimuli. Although the prevalence of CMD involves about half of all patients with chronic coronary syndromes and more than 20% of those with acute coronary syndrome, the diagnosis of CMD is often missed, leading to the underestimation of its clinical importance. The established and validated techniques for the measurement of coronary microvascular function are invasive and expensive. An ideal method to assess endothelial dysfunction should be accurate, non-invasive, cost-effective and accessible. There are varieties of biomarkers available, potentially involved in microvascular disease, but none have been extensively validated in this heterogeneous clinical population. The investigation of potential biomarkers linked to microvascular dysfunction might improve the assessment of the diagnosis, risk stratification, disease progression and therapy response. This review article offers an update about traditional and novel potential biomarkers linked to CMD.

Functional role of miR-34a in diabetes and frailty

Emerging evidence has shown that microRNAs (miRNAs) play critical role in the pathogenesis of several disorders. In the present minireview, we focus our attention on the functional role of a specific miRNA, namely miR-34a, in the pathophysiology of frailty and diabetes mellitus. Based on the current literature, we speculate that this miRNA may serve as a potential biomarker of frailty in diabetic older adults. Additionally, its actions on oxidative stress might represent a druggable target to obtain new potentials treatments.

Comparison of Risk Assessment Strategies for Patients with Diabetes Mellitus and Stable Chest Pain: A Coronary Computed Tomography Angiography Study

BACKGROUND

To compare two risk assessment strategies to identify individuals likely to benefit from further imaging testing in patients with diabetes mellitus (DM) and stable chest pain (SCP) suspected of obstructive coronary artery disease (CAD).

METHODS

602 DM patients referred to coronary computed tomography angiography (CCTA) for SCP were included. They were divided into high- and low-risk groups according to the 2016 National Institute of Health and Care Excellence guideline-determined strategy (NICE strategy) which focused on symptom evaluation and 2019 European Society of Cardiology guideline-determined strategy (ESC strategy) which was based on pretest probability (PTP) sequentially determined by the ESC-PTP estimator and risk factor-weighted clinical likelihood (RF-CL) model, respectively. The associations of clinical outcomes with risk groups and net reclassification improvement (NRI) were evaluated.

RESULTS

The NICE and ESC strategy classified 44% and 39% patients into the low-risk group, respectively. Compared to the NICE strategy, the ESC strategy indicated stronger associations between risk groups and events (hazard ratios: 4.24 versus 1.91), intensive clinical management, and a positive NRI (27.71%, p < 0.0001). The application of the RF-CL model ameliorated the underestimation of risk in patients with borderline ESC-PTP, which principally account for the improvement of the ESC strategy.

CONCLUSION

Compared to the NICE strategy, the ESC strategy seemed to be associated with greater efficiency in identifying high risk individuals in patients with DM and SCP.

Pathophysiology of Coronary Microvascular Dysfunction

Ischemic heart disease (IHD) is commonly recognized as the consequence of coronary atherosclerosis and obstructive coronary artery disease (CAD). However, a significant number of patients may present angina or myocardial infarction even in the absence of any significant coronary artery stenosis and impairment of the coronary microcirculation has been increasingly implicated as a relevant cause of IHD. The term "coronary microvascular dysfunction" (CMD) encompasses several pathogenic mechanisms resulting in functional and/or structural changes in the coronary microcirculation and determining angina and myocardial ischemia in patients with angina without obstructive CAD ("primary" microvascular angina), as well as in several other conditions, including obstructive CAD, cardiomyopathies, Takotsubo syndrome and heart failure, especially the phenotype with preserved ejection fraction. The pathogenesis of CMD is complex and involves the combination of functional and structural alterations leading to impaired coronary blood flow and resulting in myocardial ischemia. In the absence of therapies specifically targeting CMD, attention has been focused on the role of modifiable risk factors. Here, we provide updated evidence regarding the pathophysiological mechanisms underlying CMD, with a particular focus on the role of cardiovascular risk factors and comorbidities. Moreover, we discuss the specific pathogenic mechanisms of CMD across the different cardiovascular diseases, aiming to pave the way for further research and the development of novel strategies for a precision medicine approach.

Quantitative sensory testing can effectively predict cardiovascular autonomic neuropathy in patients with type 2 diabetes mellitus

AIMS

Cardiovascular autonomic neuropathy (CAN) is one of the most serious types of diabetic autonomic neuropathy and is a class of small fibre neuropathy. Among many inspection methods, quantitative sensory testing is an effective and convenient method for diagnosing diabetic small fibre neuropathy. This cross-sectional study aimed to identify the correlation between the development of cardiovascular autonomic neuropathy and quantitative sensory testing parameters in patients with type 2 diabetes mellitus.

METHODS

A total of 266 participants with type 2 diabetes mellitus from Nanjing Drum Tower Hospital were enrolled in this study, and each of them received cardiovascular reflex tests (CARTs) and quantitative sensory testing, including testing of cold, warm, cold pain, and heat pain detection thresholds (CDT, WDT, CPT, and HPT, respectively). The results of CARTs were compared with the thermal detection thresholds in quantitative sensory testing by using SPSS 26.0.

RESULTS

A total of 266 participants were divided into the CAN group, early CAN (ECAN) group, and without CAN (NCAN) group. There were significant differences in quantitative sensory testing parameters among three groups, and CARTs presented a positive correlation with the WDT and HPT and a negative correlation with the CDT. Moreover, after adjusting for age, sex, diabetes duration, and other influencing factors, WDT, HPT, and CDT were independent risk factors for cardiovascular autonomic neuropathy.

CONCLUSIONS

The thermal detection thresholds, including cold, warm, and heat pain detection thresholds, in quantitative sensory testing were found to be significantly related to the results of CARTs. Some thermal detection thresholds were independent risk factors for cardiovascular autonomic neuropathy. Therefore, this study showed that quantitative sensory testing has a reliable predictive ability for the occurrence and development of cardiovascular autonomic neuropathy.

Better Islet Function and Cardiovascular Autonomic Function in Chinese Type 2 Diabetic Patients with Pure Small Fiber Neuropathy than with Mixed Neuropathy

INTRODUCTION

The clinical characteristics and outcomes of small fiber neuropathy (SFN) in Chinese patients with type 2 diabetes mellitus (T2DM) have not been thoroughly described. In this study, we investigated the metabolic and neurological indexes and the prognosis of patients with T2DM based on skin biopsy.

METHODS

A total of 34 healthy Chinese volunteers were recruited for skin biopsy to establish the reference range of intra-epidermal nerve fiber density (IENFD), and 89 patients with T2DM attending the Nanjing Drum Tower Hospital were evaluated at baseline. Of these 89 patients, 17 with pure SFN and nine with mixed diabetic polyneuropathy (DPN) were reassessed at the end of the follow-up.

RESULTS

Glycated hemoglobin and postprandial blood glucose levels were lower (P = 0.005 and P = 0.041, respectively) and postprandial C-peptide and insulin levels were higher (P = 0.001 and P = 0.019, respectively) in the pure SFN group than in the mixed DPN group. A partial correlation study showed that there was a negative correlation between IENFD of the distal leg and cardiovascular autonomic reflex test (CART) scores (r = - 0.513, P = 0.001) after adjusting for age and duration of diabetes. Only vitamin B12 level (P = 0.028) and motor nerve conduction velocity (MCV) of the common peroneal nerve (P = 0.045) were increased in the patients with pure SFN at the final visit while MCVs of the common peroneal nerve (P = 0.025) and tibial nerve (P = 0.047) were decreased in the mixed DPN group at the final visit.

CONCLUSION

Better islet function and cardiovascular autonomic function were observed in patients with pure SFN compared with mixed DPN. The metabolic and neurological indexes remained relatively stable in the patients with pure SFN during the follow-up.

Lipids and peripheral neuropathy

PURPOSE OF REVIEW

Hyperlipidaemia is associated with the development of neuropathy. Indeed, a mechanistic link between altered lipid metabolism and peripheral nerve dysfunction has been demonstrated in a number of experimental and clinical studies. Furthermore, post hoc analyses of clinical trials of cholesterol and triglyceride-lowering pharmacotherapy have shown reduced rates of progression of diabetic neuropathy. Given, there are currently no FDA approved disease-modifying therapies for diabetic neuropathy, modulation of lipids may represent a key therapeutic target for the treatment of diabetic nerve damage. This review summarizes the current evidence base on the role of hyperlipidaemia and lipid lowering therapy on the development and progression of peripheral neuropathy.

RECENT FINDINGS

A body of literature supports a detrimental effect of dyslipidaemia on nerve fibres resulting in somatic and autonomic neuropathy. The case for an important modulating role of hypertriglyceridemia is stronger than for low-density lipoprotein cholesterol (LDL-C) in relation to peripheral neuropathy. This is reflected in the outcomes of clinical trials with the different therapeutic agents targeting hyperlipidaemia reporting beneficial or neutral effects with statins and fibrates. The potential concern with the association between proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor therapy and cognitive decline raised the possibility that extreme LDL-C lowering may result in neurodegeneration. However, studies in murine models and data from small observational studies indicate an association between increased circulating PCSK9 levels and small nerve fibre damage with a protective effect of PCSK9i therapy against small fibre neuropathy. Additionally, weight loss with bariatric surgery leads to an improvement in peripheral neuropathy and regeneration of small nerve fibres measured with corneal confocal microscopy in people with obesity with or without type 2 diabetes. These improvements correlate inversely with changes in triglyceride levels.

SUMMARY

Hyperlipidaemia, particularly hypertriglyceridemia, is associated with the development and progression of neuropathy. Lipid modifying agents may represent a potential therapeutic option for peripheral neuropathy. Post hoc analyses indicate that lipid-lowering therapies may halt the progression of neuropathy or even lead to regeneration of nerve fibres. Well designed randomized controlled trials are needed to establish if intensive targeted lipid lowering therapy as a part of holistic metabolic control leads to nerve fibre regeneration and improvement in neuropathy symptoms.

Cardiovascular autonomic neuropathy in diabetes: Pathophysiology, clinical assessment and implications

Cardiovascular autonomic neuropathy (CAN) is a debilitating condition that mainly occurs in long-standing type 2 diabetes patients but can manifest earlier, even before diabetes is diagnosed. CAN is a microvascular complication that results from lesions of the sympathetic and parasympathetic nerve fibers, which innervate the heart and blood vessels and promote alterations in cardiovascular autonomic control. The entire mechanism is still not elucidated, but several aspects of the pathophysiology of CAN have already been described, such as the production of advanced glycation end products, reactive oxygen species, nuclear factor kappa B, and pro-inflammatory cytokines. This microvascular complication is an important risk factor for silent myocardial ischemia, chronic kidney disease, myocardial dysfunction, major cardiovascular events, cardiac arrhythmias, and sudden death. It has also been suggested that, compared to other traditional cardiovascular risk factors, CAN progression may have a greater impact on cardiovascular disease development. However, CAN might be subclinical for several years, and a late diagnosis increases the mortality risk. The duration of the transition period from the subclinical to clinical stage remains unknown, but the progression of CAN is associated with a poor prognosis. Several tests can be used for CAN diagnosis, such as heart rate variability (HRV), cardiovascular autonomic reflex tests, and myocardial scintigraphy. Currently, it has already been described that CAN could be detected even during the subclinical stage through a reduction in HRV, which is a non-invasive test with a lower operating cost. Therefore, considering that diabetes mellitus is a global epidemic and that diabetic neuropathy is the most common chronic complication of diabetes, the early identification and treatment of CAN could be a key point to mitigate the morbidity and mortality associated with this long-lasting condition.

Cardiovascular autonomic neuropathy in people with type 2 diabetes mellitus; investigation of its association with classical cardiovascular risk factors using cardiovascular autonomic reflex tests: a cross-sectional study

Background

People with type 2 diabetes mellitus (DM) are at increased risk of cardiovascular disease (CVD). Cardiovascular autonomic neuropathy (CAN) is an underdiagnosed risk factor for CVD, which is prevalent among people with 2DM and can lead to CVD and CVD-related mortality. Little is known about the risk factors associated with CAN in type 2DM. Thus, the study was aimed to assess CAN using five cardiovascular autonomic reflex tests (represented by Ewing’s score) and explore the factors associated with CAN in people with type 2DM. The studied factors include traditional and serological CVD risk factors obtained from a fasting blood sample and cardiorespiratory fitness (CRF) obtained via attainment of the highest peak of volumes of O₂ (VO_2Peak).

Results

Univariate analysis revealed a significant positive correlation between resting systolic blood pressure (SBP) and Ewing’s score (r=0.47, p=.02) and an inverse correlation between VO_2Peak and Ewing’s score (r=−0.64, p=.001). Multivariate linear regression revealed that a significant model that included resting SBP and VO_2Peak explained 93.8% of Ewing’s score variance.

Conclusion

CAN was associated with two CVD parameters, including resting SBP and CRF, which may indicate the importance of controlling these two factors to prevent or reduce CAN in people with type 2DM.

Predictive value of visit-to-visit blood pressure variability for cardiovascular events in patients with coronary artery disease with and without diabetes mellitus

Background

High blood pressure is a major risk factor for cardiovascular disease. Visit-to-visit blood pressure variability (BPV) has recently been shown to predict cardiovascular outcomes. We investigated the predictive value of BPV for major adverse cardiovascular events (MACE) among patients with coronary artery disease (CAD), with and without type 2 diabetes mellitus (T2DM).

Methods

Patients with stable CAD were enrolled and monitored for new MACE. Visit-to-visit BPV was defined as the coefficient of variation (CV) of systolic and diastolic BP across clinic visits. Multivariable logistic regression analysis was performed to evaluate the association of BPV with MACE. Area under the receiver operating characteristic curve (AUC) was used to assess its predictive ability.

Results

Among 1140 Chinese patients with stable CAD, 192 (17%) experienced a new MACE. In multivariable analyses, the risk of MACE was significantly associated with CV of systolic BP (odds ratio [OR] for highest versus lowest quartile, 3.30; 95% CI 1.97–5.54), and diastolic BP (OR for highest versus lowest quartile, 2.39; 95% CI 1.39–4.11), after adjustment for variables of the risk factor model (age, gender, T2DM, hypertension, antihypertensive agents, number of BP measurements) and mean BP. The risk factor model had an AUC of 0.70 for prediction of MACE. Adding systolic/diastolic CV into the risk factor model with mean BP significantly increased the AUC to 0.73/0.72 (P = 0.002/0.007). In subgroup analyses, higher CV of systolic BP remained significantly associated with an increased risk for MACE in patients with and without T2DM, whereas the association of CV of diastolic BP with MACE was observed only in those without T2DM.

Conclusions

Visit-to-visit variability of systolic BP and of diastolic BP was an independent predictor of new MACE and provided incremental prognostic value beyond mean BP and conventional risk factors in patients with stable CAD. The association of BPV in CAD patients without T2DM with subsequent risk for MACE was stronger than in those with T2DM.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01280-z.

Diabetic heart disease: A clinical update

Diabetes mellitus (DM) significantly increases the risk of heart disease, and DM-related healthcare expenditure is predominantly for the management of cardiovascular complications. Diabetic heart disease is a conglomeration of coronary artery disease (CAD), cardiac autonomic neuropathy (CAN), and diabetic cardiomyopathy (DCM). The Framingham study clearly showed a 2 to 4-fold excess risk of CAD in patients with DM. Pathogenic mechanisms, clinical presentation, and management options for DM-associated CAD are somewhat different from CAD among nondiabetics. Higher prevalence at a lower age and more aggressive disease in DM-associated CAD make diabetic individuals more vulnerable to premature death. Although common among diabetic individuals, CAN and DCM are often under-recognised and undiagnosed cardiac complications. Structural and functional alterations in the myocardial innervation related to uncontrolled diabetes result in damage to cardiac autonomic nerves, causing CAN. Similarly, damage to the cardiomyocytes from complex pathophysiological processes of uncontrolled DM results in DCM, a form of cardiomyopathy diagnosed in the absence of other causes for structural heart disease. Though optimal management of DM from early stages of the disease can reduce the risk of diabetic heart disease, it is often impractical in the real world due to many reasons. Therefore, it is imperative for every clinician involved in diabetes care to have a good understanding of the pathophysiology, clinical picture, diagnostic methods, and management of diabetes-related cardiac illness, to reduce morbidity and mortality among patients. This clinical review is to empower the global scientific fraternity with up-to-date knowledge on diabetic heart disease.

Correlation of staging and risk factors with cardiovascular autonomic neuropathy in patients with type II diabetes mellitus

The impairment of cardiovascular autonomic control among the underdiagnosed complication of diabetes mellitus (DM) with a high prevalence rate of up to 60% in type 2 DM (T2DM). Cardiac autonomic neuropathy (CAN) is an independent risk factor for cardiovascular mortality, arrhythmia, silent ischemia, any major cardiovascular event, and heart failure. We aimed to evaluate cardiovascular autonomic activity by different physiological maneuvers, study risk factors for diabetic CAN including age, gender, duration of diabetes, body mass index (BMI), and glycemic control, and correlate CAN stage with risk factors. One hundred and forty-two T2DM patients consisted of 62 males and 80 females and 100 volunteers as a control sample. Cardiac autonomic functions were assessed by Ewing's tests. Glycated hemoglobin (HbA1c), body weight, height, body mass index (BMI), and waist-hip ratio (WHR) were also measured. Cardiovascular autonomic functions and Ewing scores were significantly different in people with diabetes when compared with control healthy subjects. Ewings test values and Ewing scores were significantly different between diabetics with and without CAN and within patients with different CAN staging. People with diabetes with CAN have a significantly longer duration of disease when compared to those without CAN. A strong association has been found between CAN severity and patient age, duration of disease, HbA1c severity, and the WHR (P < 0.001) but not with BMI. The duration of disease and HbA1c level appear to be associated with the development of CAN (P = 0.001 and P = 0.008, respectively). The poorer glycemic control and the longer the duration of the disease, the higher the prevalence of CAN in T2DM. Age, duration of disease, WHR, and HbA1c are well correlated with the severity of CAN. Parasympathetic impairment is more sensitive to the detection of autonomic dysfunctions than do sympathetic impairment.

Ischemic Heart Disease Pathophysiology Paradigms Overview: From Plaque Activation to Microvascular Dysfunction

Ischemic heart disease still represents a large burden on individuals and health care resources worldwide. By conventions, it is equated with atherosclerotic plaque due to flow-limiting obstruction in large-medium sized coronary arteries. However, clinical, angiographic and autoptic findings suggest a multifaceted pathophysiology for ischemic heart disease and just some cases are caused by severe or complicated atherosclerotic plaques. Currently there is no well-defined assessment of ischemic heart disease pathophysiology that satisfies all the observations and sometimes the underlying mechanism to everyday ischemic heart disease ward cases is misleading. In order to better examine this complicated disease and to provide future perspectives, it is important to know and analyze the pathophysiological mechanisms that underline it, because ischemic heart disease is not always determined by atherosclerotic plaque complication. Therefore, in order to have a more complete comprehension of ischemic heart disease we propose an overview of the available pathophysiological paradigms, from plaque activation to microvascular dysfunction.

Metformin may adversely affect orthostatic blood pressure recovery in patients with type 2 diabetes: substudy from the placebo-controlled Copenhagen Insulin and Metformin Therapy (CIMT) trial

Background

Metformin has been shown to have both neuroprotective and neurodegenerative effects. The aim of this study was to investigate the effect of metformin in combination with insulin on cardiovascular autonomic neuropathy (CAN) and distal peripheral neuropathy (DPN) in individuals with type 2 diabetes (T2DM).

Methods

The study is a sub-study of the CIMT trial, a randomized placebo-controlled trial with a 2 × 3 factorial design, where 412 patients with T2DM were randomized to 18 months of metformin or placebo in addition to open-labelled insulin. Outcomes were measures of CAN: Changes in heart rate response to deep breathing (beat-to-beat), orthostatic blood pressure (OBP) and heart rate and vibration detection threshold (VDT) as a marker DPN. Serum levels of vitamin B12 and methyl malonic acid (MMA) were analysed.

Results

After 18 months early drop in OBP (30 s after standing) was increased in the metformin group compared to placebo: systolic blood pressure drop increased by 3.4 mmHg (95% CI 0.6; 6.2, p = 0.02) and diastolic blood pressure drop increased by 1.3 mmHg (95% CI 0.3; 2.6, p = 0.045) compared to placebo. Beat-to-beat variation decreased in the metformin group by 1.1 beats per minute (95% CI − 2.4; 0.2, p = 0.10). Metformin treatment did not affect VDT group difference − 0.33 V (95% CI − 1.99; 1.33, p = 0.39) or other outcomes. Changes in B12, MMA and HbA_1c did not confound the associations.

Conclusions

Eighteen months of metformin treatment in combination with insulin compared with insulin alone increased early drop in OBP indicating an adverse effect of metformin on CAN independent of vitamin B12, MMA HbA_1c.

Trial registration The protocol was approved by the Regional Committee on Biomedical Research Ethics (H–D-2007-112), the Danish Medicines Agency and registered with ClinicalTrials.gov (NCT00657943).

ESC Working Group on Coronary Pathophysiology and Microcirculation position paper on 'coronary microvascular dysfunction in cardiovascular disease'

Although myocardial ischaemia usually manifests as a consequence of atherosclerosis-dependent obstructive epicardial coronary artery disease, a significant percentage of patients suffer ischaemic events in the absence of epicardial coronary artery obstruction. Experimental and clinical evidence highlight the abnormalities of the coronary microcirculation as a main cause of myocardial ischaemia in patients with 'normal or near normal' coronary arteries on angiography. Coronary microvascular disturbances have been associated with early stages of atherosclerosis even prior to any angiographic evidence of epicardial coronary stenosis, as well as to other cardiac pathologies such as myocardial hypertrophy and heart failure. The main objectives of the manuscript are (i) to provide updated evidence in our current understanding of the pathophysiological consequences of microvascular dysfunction in the heart; (ii) to report on the current knowledge on the relevance of cardiovascular risk factors and comorbid conditions for microcirculatory dysfunction; and (iii) to evidence the relevance of the clinical consequences of microvascular dysfunction. Highlighting the clinical importance of coronary microvascular dysfunction will open the field for research and the development of novel strategies for intervention will encourage early detection of subclinical disease and will help in the stratification of cardiovascular risk in agreement with the new concept of precision medicine.

Prevalence and Diagnosis of Diabetic Cardiovascular Autonomic Neuropathy in Beijing, China: A Retrospective Multicenter Clinical Study

Cardiovascular autonomic neuropathy (CAN) is a debilitating condition occurring among diabetic patients especially those with long duration of disease. Whereas incidences and treatment of CAN has been well described for Western populations, fewer studies have been conducted among the Chinese. This study, therefore, aimed to assess the prevalence of CAN among sampled Chinese diabetic patients. Accordingly, 2,048 participants with a history of type 1 diabetes mellitus (T1DM, 73) and type 2 diabetes mellitus (T2DM, 1975) were randomly sampled from 13 hospitals. Patients’ biodata were recorded, and autonomic nervous system function tests performed to aid in the preliminary diagnosis of CAN. The final CAN diagnosis was based on the Ewing’s test in which heart rate variation (HRV) values were evaluated through deep-breathing (DB), lying-to-standing (LS), and Valsalva (V) tests. Systolic blood pressure (SBP) variation values were also evaluated through LS. In the T1DM group, 61.6% patients were diagnosed with CAN and no differences were observed in the baseline and clinical data between this group and those without CAN (P > 0.05). In the T2DM group, 62.6% patients were diagnosed with CAN and statistically significant differences were found between the CAN and non- CAN group with regards to age, duration of diabetes, metformin treatment, retinopathy, and hypertension history (P < 0.05). The most common manifestations of CAN included weakness (28.6%), dizziness (23.4%), frequent urination (19.6%), upper body sweating (18.3%), and nocturia (15.9%). Additionally, duration of disease and age were independent risk factors for CAN in T1DM and T2DM, respectively. On diagnosis, a combination of the V test + LS test provided the highest sensitivity of detecting CAN among T1DM group (sensitivity = 97.6%, AUC = 0.887) while for T2DM category, DB test had the highest sensitivity (83.6%), and maximal AUC (0.856) was found with V test + DB test. The overall prevalence of diabetes with CAN in the study was up to 63%.

Increased arrhythmia susceptibility in type 2 diabetic mice related to dysregulation of ventricular sympathetic innervation

Patients with type 2 diabetes mellitus (T2DM) have a greater risk of developing life-threatening cardiac arrhythmias. Because the underlying mechanisms and potential influence of diabetic autonomic neuropathy are not well understood, we aimed to assess the relevance of a dysregulation in cardiac autonomic tone. Ventricular arrhythmia susceptibility was increased in Langendorff-perfused hearts isolated from mice with T2DM (db/db). Membrane properties and synaptic transmission were similar at cardiac postganglionic parasympathetic neurons from diabetic and control mice; however, a greater asynchronous neurotransmitter release was present at sympathetic postganglionic neurons from the stellate ganglia of db/db mice. Western blot analysis showed a reduction of tyrosine hydroxylase (TH) from the ventricles of db/db mice, which was confirmed with confocal imaging as a heterogeneous loss of TH-immunoreactivity from the left ventricular wall but not the apex. In vivo stimulation of cardiac parasympathetic (vagus) or cardiac sympathetic (stellate ganglion) nerves induced similar changes in heart rate in control and db/db mice, and the kinetics of pacing-induced Ca²⁺ transients (recorded from isolated cardiomyocytes) were similar in control and db/db cells. Antagonism of cardiac muscarinic receptors did not affect the frequency or severity of arrhythmias in db/db mice, but sympathetic blockade with propranolol completely inhibited arrhythmogenicity. Collectively, these findings suggest that the increased ventricular arrhythmia susceptibility of type 2 diabetic mouse hearts is due to dysregulation of the sympathetic ventricular control.NEW & NOTEWORTHY Patients with type 2 diabetes mellitus have greater risk of suffering from sudden cardiac death. We found that the increased ventricular arrhythmia susceptibility in type 2 diabetic mouse hearts is due to cardiac sympathetic dysfunction. Sympathetic dysregulation is indicated by an increased asynchronous release at stellate ganglia, a heterogeneous loss of tyrosine hydroxylase from the ventricular wall but not apex, and inhibition of ventricular arrhythmias in db/db mice after β-sympathetic blockade.

Improved long-term cardiovascular outcomes after intensive versus standard screening of diabetic complications: an observational study

BACKGROUND

Complication screening is recommended for patients with type 2 diabetes (T2D), but the optimal screening intensity and schedules are unknown. In this study, we evaluated whether intensive versus standard complication screening affects long-term cardiovascular outcomes.

METHODS

In this observational study, we included 368 T2D patients referred for intensive screening provided as a 1-day session of clinical-instrumental evaluation of diabetic complications, followed by dedicated counseling. From a total of 4906 patients, we selected control T2D patients who underwent standard complication screening at different visits, by 2:1 propensity score matching. The primary endpoint was the 4p-MACE, defined as cardiovascular mortality, or non-fatal myocardial infarction, stroke, or heart failure. The Cox proportional regression analyses was used to compare outcome occurrence in the two groups, adjusted for residual confounders.

RESULTS

357 patients from the intensive screening group (out of 368) were matched with 683 patients in the standard screening group. Clinical characteristics were well balanced between the two groups, except for a slightly higher prevalence of microangiopathy in the intensive group (56% vs 50%; standardized mean difference 0.11, p = 0.1). Median follow-up was 5.6 years. The adjusted incidence of 4p-MACE was significantly lower in the intensive versus standard screening group (HR 0.70; 95% CI 0.52-0.95; p = 0.02). All components of the primary endpoint had nominally lower rates in the intensive versus standard screening group, which was particularly significant for heart failure (HR 0.43; 95% CI 0.22-0.83; p = 0.01).

CONCLUSION

Among T2D patients attending a specialist outpatient clinic, intensive complication screening is followed by better long-term cardiovascular outcomes. No significant effect was noted for cardiovascular and all-cause mortality and the benefit was mainly driven by a reduced rate of hospitalization for heart failure.

Clinical factors associated with the recovery of cardiovascular autonomic neuropathy in patients with type 2 diabetes mellitus

Background

Cardiovascular autonomic neuropathy (CAN) is a major cause of morbidity and mortality in diabetes patients. Although several risk factors for CAN progression have been established, whether CAN is reversible remains unclear and the clinical factors associated with CAN recovery have not been identified. This study aimed to determine clinical factors related to CAN recovery.

Methods

Type 2 diabetes patients with CAN but free of cardiovascular disease at baseline were enrolled and followed for 2–3 years in this retrospective longitudinal study. CAN was classified as early (one abnormal parasympathetic test), definite (two or more abnormal parasympathetic tests), severe (definite plus orthostatic hypotension), or atypical (early plus orthostatic hypotension or orthostatic hypotension alone) based on Ewing’s method. CAN recovery was classified as partial or complete: Partial recovery was defined as one-step improvement in CAN stage (early to normal, definite to early, or severe to definite), including the disappearance of only one abnormal result in any stage. Complete recovery was defined as normalization from definite or severe CAN.

Results

Among 759 subjects with CAN, 29.9% (n = 227) experienced CAN recovery, and 1.2% (n = 9) recovered completely. In a multivariate model, younger age (odds ratio [OR] per 5-year decrease 1.49; 95% confidence interval [CI] 1.25–1.78, P < 0.001), shorter duration of diabetes (OR per 5-year decrease 1.33; 95% CI 1.05–1.67, P = 0.016), presence of micro/macroalbuminuria (OR 0.34; 95% CI 0.15–0.78, P = 0.011), body weight reduction (OR per 1-kg decrease 1.11; 95% CI 1.02–1.21, P = 0.016), and HbA1c reduction (OR per 1% decrease 1.32; 95% CI 1.05–1.67, P = 0.019) were significantly associated with composite events of partial and complete CAN recovery. Age had the highest relative significance among the associated clinical factors. In addition, younger age was the only significant factor in complete CAN recovery.

Conclusions

Younger age was the most important factor in CAN recovery in subjects with type 2 diabetes, including recovery from the definite or severe stage. HbA1c reduction, body weight reduction, no concurrent micro/macroalbuminuria, and shorter duration of diabetes were also significantly associated with CAN recovery.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0830-4) contains supplementary material, which is available to authorized users.