Comparison of vibration and flow-mediated vasodilator responses in diabetic patients

Objective: Growing frequency and life expectancy of the diabetic patients' population in all over the world and in our country increases the share of diabetic vascular complications in cardiology practice. As current treatment and prevention methods are less effective in this patient group, there is a need to for new treatment methods in that area. Exercise, which reduces metabolic and vascular problems associated with diabetes, often becomes impossible especially in advanced stage patients who need treatment the most. Since exercise and flow mediated dilation (FMD) are effective by stimulating mechanotransduction mechanisms on the endothelium, it can be expected that the same mechanisms can also be stimulated by direct vibration. Methods: In order to test this hypothesis, in the presented study, a group of 20 type-2 diabetic patients (11 males, age 56.80±11.05 and diagnosed for 15.35±8.61 years) were examined via application of a duly FMD and VMD (by performing vibration for 5 minutes with 20 Hz frequency and 3 mm vertical amplitude) to the same side forearm, with a 30 minutes interval. Using a 10 MHz linear echo probe, brachial artery diameter and flow velocities were recorded before and later of FMD and VMD applications at 2-minute intervals for 10 minutes. Then brachial artery flow and resistances has been calculated for each stage. Results: In the first minute after FMD and VMD applications, BA diameter and flow velocities increased evidently and significantly and vascular resistance decreased in a similar way. None of the corresponding FMD or VMD parameters in the first minute was different. The artery diameters after FMD and VMD, in the first minute, were increased by 6.04 ± 5.29 and 5.49 ± 5.21 % respectively. At the tenth minute, these figures decreased to 1.73 ± 3.21 and 2.05 ± 3.31 %. In the FMD series, all parameters except artery diameter returned to their baseline values after the fourth minute. After VMD, all parameters also tended to approach their baseline values after the first minute, but the recovery was much slower. At each stage after the first minute, the VMD averages were higher than the baseline value and their corresponding FMD values. Conclusion: The results of the study indicate that vibration may be a powerful, long-lasting and feasible treatment option in patients with peripheral perfusion failure developed due to diabetic macro and microvascular complications.