Advanced Search

Study Preview



Study Title and Description

Acute effect of caffeine on arterial stiffness and aortic pressure waveform.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on cardiovascular outcomes?
  • Comments Comments (
    0
    ) |

Primary Publication Information
  • Comments Comments (
    0
    ) |
TitleData
Title Acute effect of caffeine on arterial stiffness and aortic pressure waveform.
Author A Mahmud,J Feely,
Country
Year 2001
Numbers

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Cardiovascular Design
Design Details
Question... Follow Up Answer Follow-up Answer
What outcome is being evaluated in this paper? Cardiovascular
  • Comments Comments (
    0
    ) |
What is the objective of the study (as reported by the authors)? Because early wave reflection and PWV, measures of arterial stiffness, are associated with an increase in systolic blood pressure, we examined the effect of caffeine on these properties of large arteries.
  • Comments Comments (
    0
    ) |
Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) Subjects Seven healthy volunteers (4 female) abstained from smoking and drinking alcohol- or caffeine-containing beverages in the 12 hours before the study. Subjects received 250 mL freshly brewed caffeinated or decaffeinated coffee in a randomized, double-blind, crossover protocol on 2 separate days >/=1 week apart. The caffeine content of the 250 mL coffee determined by high-pressure liquid chromatography was 150 +/- 5 and <2 mg for caffeinated and decaffeinated coffee, respectively. The hemodynamic measurements were performed in a quiet room at 20°C to 23°C. The subjects were supine throughout the study. After a stable baseline measurement was obtained, hemodynamic measurements were made in the left arm at baseline and 30, 60 and 90 minutes after ingestion of coffee. Blood Pressure Measurements Brachial blood pressure and heart rate were measured with an automated digital oscillometric blood pressure monitor (Omron model HEM 705-CP), and a mean of 3 readings was taken. Deviation of the Aortic Pressure Waveform The radial artery pulse was recorded by applanation tonometry with a high-fidelity micromanometer (BPAS-1, PPWV Medical). The central aortic waveform was derived from radial tonometry by use of a previously validated transfer factor within the software package (Sphygmocor). The augmentation index (AI%) was calculated from the derived aortic pressure waveform as the height of the late systolic peak divided by pulse pressure. The validity of the derived AI% has been confirmed by simultaneous direct central aortic measurements. Pulse Wave Velocity (PWV) Measurements Carotid-femoral PWV (m/s) was determined by using the foot-to-foot method with the Complior device from simultaneous recordings by 2 pressure-sensitive transducers and measuring the time delay of successive records from the foot of each wave divided by the measured surface distance between the transducers. The validity of the Complior has been established. Statistical Analysis The baseline values for both study days were analyzed by 1-way ANOVA. The effect of coffee on time-dependent patterns of evolution of blood pressure, PWV, and AI% was tested for treatment and period effects by repeated-measures ANOVA. Because blood pressure influences arterial hemodynamic parameters, we made a complementary analysis on these variables from baseline over time, adjusting for changes in blood pressure at the time they were measured. Comparison of the area under the blood pressure–time curve corrected to the baseline reading by the trapezoidal rule was made by the Wilcoxon rank-sum test. Correlations were examined by least-squares regression analysis. The results are presented as mean +/-SEM (*P <0.05).
  • Comments Comments (
    0
    ) |
How many outcome-specific endpoints are evaluated? 4
  • Comments Comments (
    0
    ) |
What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Blood pressure (central [aortic] and peripheral [brachial] SBP and DBP)
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately). 2 Heart rate
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).3 Aortic stiffness (pulse wave velocity [PWV])
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).4 Arterial wave reflection (augmentation index [AIx]
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).5
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).6
  • Comments Comments (
    0
    ) |
Clinical, physiological, other Physiological
  • Comments Comments (
    0
    ) |
What is the study design? Controlled Trial
  • Comments Comments (
    0
    ) |
Randomized or Non-Randomized? RCT
  • Comments Comments (
    0
    ) |
What were the diagnostics or methods used to measure the outcome? Objective
  • Comments Comments (
    0
    ) |
Optional: Name of Method or short description Various instruments used to measure endpoints
  • Comments Comments (
    0
    ) |
Caffeine (general) Caffeine (general)
  • Comments Comments (
    0
    ) |
Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other? Coffee
  • Comments Comments (
    0
    ) |
Measured or self reported? Measured
  • Comments Comments (
    0
    ) |
Children, adolescents, adults, or pregnant included? Adults
  • Comments Comments (
    0
    ) |
What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) Each subject served as their own control (decaffeinated coffee)
  • Comments Comments (
    0
    ) |
What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) None
  • Comments Comments (
    0
    ) |
What conflicts of interest were reported? No information provided
  • Comments Comments (
    0
    ) |
Refid 11509481
  • Comments Comments (
    0
    ) |
What were the sources of funding? No information provided
  • Comments Comments (
    0
    ) |




Results & Comparisons

No Results found.