Dissipative energy loss within the left ventricle detected by vector flow mapping in diabetic patients with controlled and uncontrolled blood glucose levels.Int J Cardiovasc Imaging. 2017 Aug; 33(8):1151-1158.IJ
Diabetes mellitus (DM) is related to increased risks of cardiovascular diseases, such as myocardial infarction, diabetic cardiomyopathy and secondary hypertension. Dissipative energy loss (EL) derived from vector flow mapping (VFM) is thought to reflect the efficiency of blood flow and has been deemed to be an index for the evaluation of left ventricular function. Our study aimed to investigate the value of dissipative EL in diabetic patients with controlled and uncontrolled blood glucose by VFM. Eighty-eight patients with DM and 58 age-matched healthy controls were recruited. All of the patients received echocardiography examinations. VFM analyses were executed to calculate the EL values according to the apical four-chamber examinations from the left ventricle (LV) view. Our results showed that diastolic EL was compromised in the controlled-blood glucose (59.19 mV/m vs. 32.68 mV/m, p = 0.039) patients and was more dramatically increased in the uncontrolled blood glucose group (88.84 mV/m vs. 32.68 mV/m, p < 0.001) compared with the healthy controls. The impairment of systolic EL was observed only in the uncontrolled blood glucose patients (39.65 mV/m vs. 20.29 mV/m, p < 0.001) and not in the controlled blood glucose patients (29.25 mV/m vs. 20.29 mV/m, p = 0.072). Multivariate backward stepwise linear regression analysis revealed that the HbA1c level was independently related to the diastolic EL (β = 0.233, p = 0.026) and systolic EL (β = 0.237, p = 0.023). VFM is feasible and reproducible for assessing LV dissipative EL in DM patients with normal LVEF values in whom diastolic EL may be a more vulnerable indicator of early LV cardiac dysfunction in patients with DM. However, LV systolic EL may be a sensitive indicator of preclinical LV dysfunction for patients with DM with uncontrolled blood glucose levels. Uncontrolled blood glucose, which is independently correlated with subclinical LV dysfunction, may lead to increases in systolic EL and diastolic EL in LV.