Smoking and antihypertensive medication: interaction between blood pressure reduction and arterial stiffness

To investigate how cigarette smoking and antihypertensive drug therapy may interact to affect cardiovascular disease, in this prospective study we administered amlodipine to hypertensive smokers and non-smokers and compared blood pressure reduction and indices of arterial stiffness. We measured blood pressure (BP), heart rate (HR), brachial-ankle pulse wave velocity (baPWV), and the carotid augmentation index (AIx) by using a non-invasive automated device in 101 hypertensive patients at baseline and at 1, 3, and 6 months of amlodipine administration (5.0 mg). At baseline, the AIx was significantly lower in smokers (n=27) than in non-smokers (n=74) (27.3% +/- 13.3% vs. 33.3% +/- 11.4%). After amlodipine administration, in both the groups, the mean BP, baPWV, and AIx were significantly reduced; however, the HR did not show a statistically significant difference. The reduction in the baPWV (cm/s) at 1 and 3 months was less marked in smokers than in non-smokers (mean +/- SD: -186.6 +/- 36.5 vs. -283.6 +/- 24.5 at 1 month; -136.6 +/- 42.2 vs. -280.1 +/- 29.6 at 3 months, respectively, both p<0.05). At 6 months, these intergroup differences in the reductions of baPWV disappeared. The blunted reduction of baPWV, particularly at 3 months, was significantly associated with the extent of smoking (lifetime pack-years smoked). Changes observed in the AIx and mean BP were similar between groups throughout the study period. In the short term, cigarette smoking blunts the effect of amlodipine on the reduction of arterial stiffness, independently of the mean BP level.