Effects of cigarette smoking on carotid and radial artery distensibility

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Abstract
Cigarette smoking acutely induces a marked increase of blood pressure and heart rate. This is accompanied by a marked reduction of radial artery distensibility. Whether this reflects an alteration of arterial mechanics of large elastic arteries as well is not established, however. In this study we addressed the acute effects of smoking on the stiffness of a peripheral medium-sized muscular artery and a large elastic vessel. We studied seven healthy normotensive smokers (age 28 ± 7 years, mean ± SEM), in the absence of smoking for at least 24 h. Radial artery (NIUS 02) and carotid artery diameter (WTS) were concomitantly acquired beat-to-beat in the 5 min before, during and after smoking of a cigarette containing 1.2 mg of nicotine. Blood pressure and heart rate were concomitantly recorded by a Finapres device. Radial and carotid artery distensibility were calculated according to the Langewouters and Reneman formulae, respectively. Data were collected for consecutive 30 s periods. Statistical comparisons were performed between the three different phases and, within each phase, between 30 s periods. In five subjects the protocol was repeated after 1 week using a stran rather than a cigarette to obtain data under sham smoking. Smoking increased systolic blood pressure by 14%, diastolic blood pressure by 10% and heart rate by 27%. Radial artery diameter was reduced during smoking (−3.7%) and more so after smoking (−14.8%), while carotid artery diameter did not change significantly either during or after smoking. Radial artery distensibility was also significantly reduced only after smoking (−41.3%, P < 0.01), while carotid artery distensibility was significantly reduced both during (−33.3%) and after smoking (−27.2%) (P < 0.01 versus before). No changes in blood pressure, heart rate and arterial wall mechanics were induced by sham smoking. Acute cigarette smoking reduces distensibility not only in medium-sized but also in large elastic arteries, therefore causing a systemic artery stiffening. The mechanisms of these effects remain to be determined. However, it is likely that adrenergic mechanisms are responsible for the arterial distensibility alterations.