Background: Patients with essential hypertension have higher arterial stiffness indices, while smoking is related to a stiff vascular tree. However, the effect of smoking on arterial stiffness in white coat hypertensive (WCH) patients has not been investigated yet.

Methods: The study comprised 375 WCH patients (mean age 52 years, 149 male). The diagnosis of WCH was confirmed by a 24h Ambulatory Blood Pressure Monitoring (ABPM) into normal range. The augmentation index (AIx), a measure of arterial wave reflections, was measured by applanation tonometry (SphygmoCor), while carotid-brachial Pulse Wave Velocity (PWVc-r) and carotid-femoral PWV (PWVc-f) were measured with Complior. AIx was corrected for heart rate (AIx₇₅). Current smoking status was assessed with a standardized questionnaire.

Results: The study cohort was divided in 129 smokers and 246 non-smokers, who did not differ in SBP, BMI, heart rate and total cholesterol (p=NS). In multivariate analysis after adjusting for age and gender, AIx₇₅ was higher in smokers compared to non-smokers (26.8 vs 22.5, p<0.001). PWVc-r was also higher in smokers compared to non-smokers (8.3 ± 0.9 vs 8.0 ± 1.2, p<0.05), while no significant difference was noticed in PWVc-f. When we examined the correlation of smoking with the arterial stiffness indices, we noticed a significant correlation of AIx₇₅ with pack-years (r=0.278, p<0.001), while the stronger correlation was noticed in years of smoking with PWVc-f (r=0.425, p<0.001) and with AIx₇₅ (r=0.649, p<0.001). After adjusting for age and gender, the correlation of years of smoking with AIx₇₅ remained significant (r=0.355, p<0.0001).

Conclusion: Smoking affects wave reflections and arterial stiffness in WCH patients. Specifically, intensity/duration of smoking affects both wave reflections and arterial stiffness whereas smoking duration is a burden only to wave reflections.