Relationship Between Glycosylated Hemoglobin and Arterial Elasticity

Vascular effects following intensification of glycemic control in poorly controlled patients with long-standing type 2 diabetes mellitus

PURPOSE

The aim of the present study was to investigate the effect of intensive antidiabetic therapy on vascular indices in type 2 diabetes mellitus (T2DM) patients.

METHODS

Poorly controlled T2DM patients (n = 62, mean age 64 years, T2DM duration 14 years, HbA1c ≥ 7.5%) were studied at baseline and following intensive treatment to achieve optimal glycemic control. Brachial artery flow-mediated dilation, carotid-femoral pulse wave velocity, central augmentation index, large and small (C2) artery compliance, carotid intima-media thickness (cIMT), and ankle-brachial index were assessed at baseline and follow-up.

RESULTS

HbA1c decreased from 8.8% (8.1, 10.1) (median, interquartile range-IQ) to 7.4% (6.9, 7.8), p < 0.001. Triglycerides and high-sensitivity C-reactive protein levels were decreased by ~ 10% and 50%, respectively (p < 0.05). Maximum cIMT and C2 increased at follow-up (0.97 ± 0.25 to 1.03 ± 0.27 mm and 3.3 (2.7, 4.2) to 4.2 (3.2, 5.4) ml/mmHg × 10, respectively, p < 0.05). In subgroup analysis, the observed changes in vascular indices were not affected by diabetes duration, presence of cardiovascular disease, or insulin treatment.

CONCLUSION

In patients with long-standing T2DM, short-term aggressive glycemic control was associated with an improvement of microvascular function (C2) and deterioration of carotid atherosclerosis (IMT) without any effect on the elastic properties of large arteries.

Effect of glycemic control on markers of subclinical atherosclerosis in patients with type 2 diabetes mellitus: A review

Cardiovascular disease is the predominant cause of death in type 2 diabetes mellitus (T2DM). Evidence suggests a strong association between duration and degree of hyperglycemia and vascular disease. However, large trials failed to show cardiovascular benefit after intensive glycemic control, especially in patients with longer diabetes duration. Atherosclerosis is a chronic and progressive disease, with a long asymptomatic phase. Subclinical atherosclerosis, which is impaired in T2DM, includes impaired vasodilation, increased coronary artery calcification (CAC), carotid intima media thickness, arterial stiffness, and reduced arterial elasticity. Each of these alterations is represented by a marker of subclinical atherosclerosis, offering a cost-effective alternative compared to classic cardiac imaging. Their additional use on top of traditional risk assessment strengthens the predictive risk for developing coronary artery disease (CAD). We, herein, review the existing literature on the effect of glycemic control on each of these markers separately. Effective glycemic control, especially in earlier stages of the disease, attenuates progression of structural markers like intima-media thickness and CAC. Functional markers are improved after use of newer anti-diabetic agents, such as incretin-based treatments or sodium-glucose co-transporter-2 inhibitors, especially in T2DM patients with shorter disease duration. Larger prospective trials are needed to enhance causal inferences of glycemic control on clinical endpoints of CAD.

Subclinical vascular alterations in young adults with type 1 diabetes detected by arterial tonometry

BACKGROUND

Diabetes mellitus is characterized by a very high prevalence of atherosclerotic disease. Aims of this study were to determine arterial compliance parameters in type 1 diabetes (T1D) patients as an expression of early pre-clinical endothelial dysfunction and to evaluate the impact of glucose exposure parameters such as the duration of diabetes and glycosylated haemoglobin (HbA(1c)) on the risk of developing alterations in vascular compliance.

METHODS

23 patients with uncomplicated type 1 diabetes (mean age: 32.78 +/- 9.06 years, mean disease duration: 10.78 +/- 7.51 years, mean HbA(1c) levels: 7.7 +/- 1.9) and 26 age- and sex-matched healthy subjects (mean age: 32.3 +/- 8.51 years) were recruited. In these subjects, we evaluated arterial compliance by calibrated tonometry (HDI/Pulsewave() CR-2000). Parameters included the following: large artery elasticity (C1), small artery elasticity (C2), systemic vascular resistance (SVR) and total vascular impedance (TVI).

RESULTS

Patients with longer duration of T1D (>10 years) showed significant alterations in C2 (4.97 +/- 2.7 mL/mmHg x 100) and in SVR (1464.67 +/- 169.16 dina x s x cm(-5)) when compared with both healthy individuals (C2: 8.28 +/- 2.67 mL/mmHg x 100, p = 0.001; SVR: 1180.58 +/- 151.55 dina x s x cm(-5), p = 0.01) and patients with recent-onset disease (<or=10 years) (C2: 10.02 +/- 3.6 mL/mmHg x 100, p < 0.001; SVR: 1124.18 +/- 178.5 dina x s x cm(-5), p < 0.000). Both disease duration and HbA(1c) independently predicted impaired arterial compliance.

CONCLUSIONS

Young adult T1D patients with no signs of disease complication have detectable vessel wall abnormalities, particularly of small arteries, suggestive of hyperglycaemia-related early endothelial dysfunction.