Diabetic cardiovascular autonomic neuropathy: clinical significance, diagnosis and therapy

Autonomic neuropathy is a common and early complication of diabetes mellitus that can be present at the time of diabetes diagnosis or before, at the stage of impaired glucose tolerance. Cardiovascular autonomic neuropathy has a special significance among diabetic complications given its detrimental effect on the quality of life, its associations with other diabetic complications and its prognostic value regarding cardiovascular morbidity and mortality. Clinical manifestations of cardiovascular autonomic neuropathy, such as resting tachycardia, orthostatic hypotension, silent myocardial ischaemia and infarction as well as cardiac arrhythmias as a consequence of QT -interval prolongation all contribute to its poor prognosis. Patients with cardiovascular autonomic neuropathy are more prone to have sudden cardiac death and they have a higher risk for perioperative cardiac and respiratory arrest. Hence, screening and diagnosis of cardiovascular autonomic neuropathy in diabetic patients is crucial. Nowadays, cardiovascular autonomic reflex tests are still the gold standard of cardiovascular autonomic assessment. These tests are easy -to -perform, noninvasive, reproducible instrumental tests with high sensitivity and specificity. Among other methods of cardiovascular autonomic testing, the assessment of heart rate variability and baroreflex sensitivity provide additional prognostic information and are used as endpoints in clinical trials. This review provides the latest information on some new facilities aiming at the simplification of the diagnostic procedure such as pre-screening questionnaires and new devices as well. Glycaemic control and treatment of cardiovascular risk factors are the cornerstone of cardiovascular autonomic neuropathy management. Administration of alpha-lipoic acid is a further, pathogenetically-based causal therapeutic option with its beneficial effects proven in clinical trial. Beyond traditional measures of glycaemic control, the role of glycaemic variability and pleiotropic effects of some antidiabetic medications on neural function are of grow ing interest. Weight reduction is beneficial not only for diabetes itself but for improving autonomic control as well. Meanwhile, data on the effect of other components of lifestyle modification on autonomic function in diabetes are rather conflicting.