Abstract
Introduction
Arterial compliance (AC), known to depend on age and sex, may be severely compromised in chronic inflammatory diseases. Apart from the various definitions for arterial stiffness that are in vogue, their constituent components are often not unique.
Purpose
This study compares vascular stiffness measures in various inflammatory diseases and explores a more comprehensive description of vessel wall properties by also considering inherent associated companion metrics.
Methods
We retrospectively analyzed arterial pressure, ventricular volume by echocardiography (Vivid-7 ultrasound system), along with carotid–femoral pulse wave velocity (PWV, by SphygmoCor, Atcor). Pulse pressure (PP) equals systolic arterial pressure (SAP) minus diastolic arterial pressure (DAP). Effective arterial elastance (Ea) = 0.9 × SAP/SV where SV is stroke volume. AC=SV/PP (Figure 1A). The intrinsic companion (C) to any established difference-based metric is calculated on the basis of the squared mean, e.g., PPC2 = (SAP2 + DAP2). Clearly, AC depends on two differences, each having a companion.
Results
A total of 177 patients (age range 18 to 80 years, 49 males), characterized by inflammatory disease (51 scleroderma, 62 atherosclerosis, 35 ankylosing spondylitis, and 29 rheumatoid arthritis), yielded reduced levels of vacular compliance irrespective of the method selected. Regression analysis showed weak correlations between the various approaches (i.e., Ea, AC, PWV). Average values for AC are comparable for all 4 diagnostic groups. Ea (P<0.03) and PWV (P<0.014) are lower for ankylosing spondylitis compared to all other groups, likely due to younger age and the higher prevalence of men. Ea is highest in atherosclerosis (P<0.026) versus all other groups. SV is significantly higher in atherosclerosis (P<0.03) compared to scleroderma and rheumatoid arthritis. However, the companions may differ (Figure 1B): PPC is significantly (P=0.017) higher in atherosclerosis (156.3±16.1 mmHg) vs scleroderma (147.2±23.0 mmHg), while SVC in ankylosing spondylitis is higher (P<0.013) than in all other groups.
Conclusions
Arterial stiffness measures show poor correlation, suggesting limitations to their utility when studying the diagnostic groups described here. Consideration of the companion associated with each difference-based metric is warranted in order to perform a comprehensive analysis of clinical data when evaluating the impact on risk factors and prognosis.
Figure 1. A: Compliance components. B: Companions
Funding Acknowledgement
Type of funding source: Public grant(s) – National budget only. Main funding source(s): Russian Science Foundation