Background: Carotid intima-media thickness (CIMT) has been occasionally compared to the pulse wave velocity (PWV), but lack of correlation often found between IMT and PWV may suggest that carotid atherosclerosis and arterial stiffness may partially differ in their pathologic background. However, we found that this poor correlation may be due to transient and/or individual heart rate (HR) which can affect the value of PWV. To prove our hypothesis, we investigated correlation analysis between CIMT and convergent PWV slope, our new surrogate marker of arterial stiffness non-affected by HR.
Methods: We studied 35 healthy male participants (20~29 years old). After the 30-second Wingate Anaerobic Test with Monark ergometer resistance, 1-ch ECG, carotid ultrasonograpy, HR and brachial-ankle PWV (baPWV) reading from ear and Lt. & Rt. brachia and ankles were measured during the rest period. All PWV and HR data were sampled every 2 R-R peaks. Convergent PWV slope is calculated by linear regression slope of PWV-HR within 100-120 bpm.
Results: There was no carotid plaque in all participants. The mean ± standard deviation of Lt. baPWV, Rt. baPWV and CIMT were 5.69±0.83 m/sec, 5.81±0.92 m/sec, and 0.61±0.054 mm, respectively. The correlation coefficient between CIMT and Lt.(Rt.) baPWV/convergent PWV slope were 0.21(0.19) and 0.79(0.78), respectively.
Conclusions: Convergent PWV slope can be more strongly correlated than PWV, with CIMT. Consequently, the thicker CIMT is related to the steeper convergent PWV slope. The study of female, athletic and metabolic syndrome group is in progress and preliminary results will be presented.