Cardiovascular autonomic neuropathy and the impact on progression of diabetic kidney disease in type 1 diabetes

IntroductionWe investigated the association between cardiovascular autonomic neuropathy (CAN) and decline in kidney function in type 1 diabetes.Research design and methodsWe included 329 persons with type 1 diabetes. CAN was assessed by cardiovascular reflex tests (CARTs): heart rate response to deep breathing (E/I ratio), to standing (30/15 ratio) and to the Valsalva maneuvre. Two or more pathological CARTs defined CAN diagnosis. Outcomes were yearly change in albuminuria or yearly change in estimated glomerular filtration rate (eGFR). An endpoint of eGFR decline >30%, development of end-stage kidney disease (ESKD) or death was examined.Associations were assessed by linear and Cox regression.ResultsParticipants were aged 55.2 (9.4) years, 52% were male, with a diabetes duration of 40.1 (8.9) years, HbA1c of 7.9% (62.5 mmol/mol), eGFR 77.9 (27.7) mL/min/1.73 m2, urinary albumin excretion rate of 14.5 (7–58) mg/24 hours, and 31% were diagnosed with CAN.CAN was associated with a 7.8% higher albuminuria increase per year (95% CI: 0.50% to 15.63%, p=0.036) versus no CAN. The endpoint of ESKD, all-cause mortality and ≥30% decline in eGFR was associated with CAN (HR=2.497, p=0.0254).ConclusionCAN and sympathetic dysfunction were associated with increase in albuminuria in individuals with type 1 diabetes suggesting its role as a potential marker of diabetic kidney disease progression.

Type 2 Diabetes Mellitus: Cardiovascular Autonomic Neuropathy and Heart Rate Variability

Type 2 Diabetes Mellitus is associated with both macro- and microvascular complications. One among the latter, is cardiovascular autonomic neuropathy (CAN). CAN is attributed to cardiac arrhythmias and sudden death. Underlying pathogenesis of cardiac autonomic neuropathy is chronic hyperglycemia induced oxidative stress causing neuronal necrosis, apoptosis and death, leading to the sympathetic and parasympathetic nerve dysfunction. The balance between sympathetic and parasympathetic nervous system is reflected by heart rate variability (HRV). HRV describes “the variations of both instantaneous heart rate and R-R intervals which in turn reflects the cardiac autonomic nervous control”. HRV measured at rest is a marker of autonomic nerve function status. Thus, HRV test is recommended to diagnose diabetic CAN. Time domain parameters predominantly reflect overall autonomic activity and parasympathetic nervous system (PNS) modulations. Frequency domain parameters either reflect, sympathetic nervous system (SNS) activity, PNS activity, or the balance between the two activities. Nonlinear HRV indices marks PNS influences, SNS influences and sympatho-vagal balance. Almost all these HRV parameters are remarkably reduced in T2DM due to cardiac autonomic dysfunction. HRV is an important simple and noninvasive diagnostic tool to detect CAN.

Cardiovascular Autonomic Neuropathy in Patients with Diabetes in Cotonou, Benin: A Cross-Sectional Study

Background Diabetes mellitus is well known as a major risk factor for cardiovascular diseases. Cardiovascular autonomic neuropathy is one of the diabetes complications that has a major impact on cardiovascular morbidity and mortality in patients with diabetes. Aim : To determine the prevalence of cardiovascular autonomic neuropathy in patients with diabetes attending the diabetic center in Cotonou and to identify its risk factors. Materials and Methods : It was a cross-sectional study. Cardiovascular autonomic neuropathy was identified using deep breathing test, standind test and the blood pressure response to standing test (orthostatic hypotension). Chi square test was used for statistical analysis and différence was considered significant when p<0.05. Results : A total of 405 subjects were included in the study. Their mean age was 53.67±11,68 years and the mean diabetes duration was 6.66 years. The prevalence of cardiovascular autonomic neuropathy was 65.9%. Regarding the severity of the complication in neuropathic patients, 51.7% of them had an early neuropathy, 41.2% have presented a moderate neuropathy and 7.1% have presented a severe neuropathy. Factors associated with cardiovascular autonomic neuropathy were age of patients (p = 0.0002), diabetes duration (p = 0.0012), hypertension (p =0.0015), dyslipidemia (p = 0.027) and high pulsed blood pressure (p = 0.032) Conclusion : Cardiovascular autonomic neuropathy is a very frequent complication of diabetes mellitus. Unfortunately this complication of diabetes is not often explored in the patient's follow-up examination. As this complication is recognised to be associated with high cardiovascular morbidity and mortality, systematic screening can be recommanded in patients with long duration of diabetes or presenting an other cardiovascular risk factor.

Cardiovascular Autonomic Reflex Tests and 7 Heart Rate Variability Indices for Early Diagnosis of Cardiovascular Autonomic Neuropathy in Type 2 Diabetes Individuals

Background: Cardiovascular autonomic neuropathy (CAN) is a common complication of type 2 Diabetes mellitus (T2D), and prevalence varies according to the methodology used. CAN should be diagnosed in the subclinical stage when an intensive treatment of T2D could avoid the progression to irreversible phases. Objective: Determine the prevalence of early involvement (EI) of CAN in T2D individuals comparing two methodologies. Methods: This was a cross-sectional study that included 183 T2D individuals who were monitored in a Tertiary centre. The diagnosis of CAN was based on the results of four cardiovascular autonomic reflex tests (CARTs: expiration-inspiration index, Valsalva maneuver, orthostatic test, and changes in blood pressure after standing) and of seven heart rate variability (7HRV) indices (CARTs plus the spectral analysis). The findings were validated in an independent cohort comprised of 562 T2D individuals followed in a Primary care setting. Results: With the use of 7HRV, 30.6% and 77.8% of individuals in the Tertiary and in the Primary centers, respectively, were classified as without CAN; 25.1% and 15.3% as EI and 44.3% and 6.9% as definitive CAN, respectively. The use of CARTs decreased the proportion of individuals without CAN in both centers (7.1% and 47%) and increased the frequency of EI (30.6% and 36.6%) and definitive CAN (62.3% and 16.4%), respectively. The concordance between both evaluated methodologies was weak. Conclusion: Higher proportions of T2D individuals were diagnosed with EI and with definitive CAN with the use of CARTs.

UPDATE OF CARDIOVASCULAR AUTONOMIC NEUROPATHY IN PATIENTS WITH DIABETES

The burden of diabetic cardiovascular autonomic neuropathy (CAN) is expected to increase due to the diabetes epidemic and its early and widespread appearance. CAN has a definite prognostic role for mortality and cardiovascular morbidity. Putative mechanisms for this are tachycardia, QT interval prolongation, orthostatic hypotension, reverse dipping, and impaired heart rate variability, while emerging mechanisms like inflammation support the pervasiveness of autonomic dysfunction. Efforts to overcome CAN under-diagnosis are: by promoting screening for symptoms and signs; by simplifying cardiovascular reflex tests.