Aortic Augmentation Index is not a Useful Index of Cardiovascular Risk in Type 2 Diabetes

Background: Impairment of arterial properties has been suggested as a pathological link between diabetes and adverse cardiovascular (CV) events. Accumulating evidence has supported a role for reduced nocturnal blood pressure (BP) reduction in predicting CV risk. In light of the clinical importance of CV risk in diabetic patients, the question of whether normotensive Type 2 diabetic patients have increased CV risk as determined by augmentation index (AI) value deserves further attention. The association between AI value and the magnitude of nocturnal BP reduction is also of interest. Purpose: This study aimed to compare AI between normotensive Type 2 diabetic patients and mildly hypertensive patients. The association between AI and the magnitude of nocturnal BP reduction in Type 2 diabetic patients was also examined. Methods: A total of 113 participants were included in this study. AI was derived by pulse wave analysis using radial applanation tonometry coupled with the generalized transfer function. Ambulatory BP measurements were performed over a 24-hour period. Results: There was no significant difference in AI between the diabetic patients and the mildly hypertensive patients after adjustment of age and body height. On the other hand, the diabetic patients exhibited a significantly lesser degree of nocturnal BP reduction than the mildly hypertensive patients even after adjusting conventional CV risk. AI was not correlated to the magnitude of nocturnal BP reduction in the diabetic patients. Conclusions: The diabetic patients did not have higher AI than mild hypertensive patients, whereas the diabetic patients had significant blunted nocturnal BP reduction than the mildly hypertensive patients. The utility of AI as a maker for CV risk in normotensive Type 2 diabetic patients remained to be determined.