| Summary: | Objective: To investigate carotid strain and displacement and to assess their relations with arterial stiffness and cardiac systolic and diastolic parameters.
Methods: Study population consisted of 40 healthy subjects (aged 17–38, median-22). All subjects underwent comprehensive transthoracic echocardiography and ultrasound carotid exams. Peak carotid longitudinal, circumferential strains and longitudinal and radial displacement were measured using two-dimensional Speckle Tracking Imaging. Aortic (at the level of aortic root) and carotid stiffness was calculated using wall-tracking software.
Results: Values for carotid strains and displacements are shown in table 1. Test-retest reliability was higher for longitudinal strain and displacement as compared to radial displacement. Univariant analysis revealed direct associations between longitudinal carotid displacement and carotid (r=0.78) and aortic (r=0.66) distensibility coefficient (p<0.01). Direct correlations were also observed between carotid longitudinal strain and left ventricular (LV) fractional shortening (r=0.33), E/A (r=0.30), relative LV posterior wall thickness (r=0.28), ventricular septum thickness (r=−0.25) (p<0.05). These relations were tested by multivariate linear regression after adjusting for potential confounders (age, blood pressure, male gender, weight). The model demonstrated that both systolic and diastolic heart parameters are independent determinants of longitudinal carotid strain (Table 2).
Conclusions: Carotid strain and displacement are important reproducible parameters of regional carotid mechanics. They are directly related with both aortic and carotid stiffness. Both systolic and diastolic parameters of left ventricular influence the carotid strain. Change in longitudinal carotid strain might serve as an early marker of cardiovascular disease.
L S, %
L SR
L D, mm
C S, %
C SR
RD, mm
10.8±4.1
1.5±0.6
0.45±0.1
7.8±1.7
0.8±0.17
0.27±0.6
Table 1Peak Longitudinal (L) and Circumferential (C) Strain (S) and Strain Rate (SR), Longitudinal (L D) and Radial (R D) Displacement of carotid arteries
Data is expressed as mean ± SD; L S – peak Longitudinal Strain, L SR – peak Longitudinal Strain Rate, L D – peak Longitudinal Displacement, C S – peak Circumferential Strain C SR – peak Circumferential Strain Rate, R D – peak Radial Displacement
β
p
Carotid Stiffness β
−0.49
0.03
Aortic Stiffness, β
−0.42
0.04
LV fractional shortening
0.38
0.048
relative LV posterior wall thickness
0.19
0.16
ventricular septum thickness
0.17
0.24
E/A
0.40
0.045
Table 2Independent relations of longitudinal carotid strain with arterial stiffness and cardiac parameters
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