OBJECTIVE
To study the diagnostic value and thresholds in diagnosing the early vascular aging (EVA) for the novel Start national vascular wall stiffness index in the population of patients with metabolic syndrome (MetS) and compare with available methods.
MATERIAL AND METHODS
A prospective open-label cohort study using general practice data was performed. Seven hundred fifty patients aged 35 to 80 with MetS were examined (IDF criteria, 2005). All patients had their vascular stiffness and central hemodynamics parameters measured, the Start index was calculated using an online calculator, and vascular age (VA) was calculated using generally accepted methods. Since the calculation of the Start index was based on the carotid-femoral pulse wave velocity (cfPWV), its Stelari Start index for the elastic section of the arteria was used. According to European population data, the EVA was defined as the cfPWV values exceeding the expected age-average values by 2 or more standard deviations (SD).
RESULTS AND DISCUSSION
A high correlation was observed between the values of the Stelari Start index and the cfPWV, with an increase in the scatter of the Stelari Start index values, starting from the cfPWVf level of about 11 m/s. According to the results of the ROC analysis, the largest values of the area under the curve (AUC) were obtained for the instrumental parameters — cfPWV and the Stelari Start index (AUC >0.81). Methods based on clinical characteristics in this group of patients have lower diagnostic values. It has been shown that despite the high diagnostic value of cfPWV for all ranges of systolic blood pressure (SBP), it decreases with an increase in SBP (for example, with SBP of 130—139 mmHg, the AUC is 0.980, and 0.864 with SBP >160 mmHg). For the Stelari Start index, it was possible to almost completely neutralize the effect of the blood pressure level on the diagnostic value of the method using the correction of the pressure factor when measuring cfPWV. The threshold for the diagnosis of EVA in MetS patients for the Stelari Start index (based on cfPWV) was 14.43.
CONCLUSION
The carotid-femoral pulse wave velocity is the most widely used indicator of arterial stiffness. However, this method has several limitations and inaccuracies, including the effect of blood pressure on this index. The novel Start national vascular wall stiffness index (stiffness of arteries) is highly diagnostic for detecting early vascular aging in patients with metabolic syndrome. In addition, this index allows for neutralizing the influence of blood pressure on the study results and improves the stratification of cardiovascular risk in this group. It should be noted that further studies are required to establish the Start index thresholds for other regions of the arterial bed and their corresponding pulse wave velocity types.
