Acute effects of caffeine and tobacco on arterial function and wave travel.
BACKGROUND
Caffeine and tobacco consumption are risk factors for heart failure, but their effects remain controversial. It has been hypothesized that they cause alterations in arterial stiffness and arterial wave travel which may increase ventricular loading. In this study the authors examined the influence of these widely used stimulants on wave intensity and arterial stiffness parameters using carotid wave intensity analysis.


METHODS
A new Doppler-based ultrasound method was used to measure the acute effects of caffeine and tobacco on wave intensity in the right common carotid artery. The measurements enabled changes in arterial stiffness parameters to be recorded.


RESULTS
In 17 subjects compared with 10 controls, caffeine increased blood pressure, early systolic wave intensity and wave speed, but late-systolic wave intensity and mid-systolic reflections were unchanged. In 11 smokers studied before and after smoking one cigarette, blood pressure and arterial stiffness increased but wave intensity was unchanged. No changes were observed in the controls.


CONCLUSIONS
Increased wave intensity during ejection after caffeine suggested sympathomimetic effects on the left ventricular function. Increased wave speed in the common carotid artery implied augmented central loading after caffeine, but the absence of measurable changes in local arterial stiffness in the carotid artery suggested more complex and regional effects. Cigarette smoking acutely increased local arterial stiffness in the common carotid artery. These changes can be detected using wave intensity analysis.
Swampillai
J
J
Wales Heart Research Institute, Wales College of Medicine, Cardiff University, Cardiff, UK. janiceswampillai@msn.com
Rakebrandt
F
F
Morris
K
K
Jones
C J H
CJ
Fraser
A G
AG
D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects; D002110:Caffeine / Q000009:adverse effects*; D002343:Carotid Artery, Internal / Q000187:drug effects* / Q000502:physiology; D016022:Case-Control Studies; D003069:Coffee / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D018608:Ultrasonography, Doppler; D014655:Vascular Resistance / Q000187:drug effects
D003069:Coffee; D002110:Caffeine