The Impact of Caffeine on Brachial Endothelial Function in Healthy Subjects and in Patients With Ischemic Heart Disease

The Impact of Caffeine on Brachial Endothelial Function in Healthy Subjects and in Patients With Ischemic Heart Disease

The Impact of Caffeine on Brachial Endothelial Function in Healthy Subjects & in Patients With Ischemic Heart Disease

Prior work (Chris, M. et al, Clinical Science 2005; 109, 55-60) has demonstrated that drinking a cup of coffee (80-100 mg of caffeine) an hour before endothelium-dependent FMD (flow-mediated dilatation) of the brachial artery, effects endothelial function in healthy adults subjects. This effect might be attributed to caffeine, given that decaffeinated coffee (<2 mg of caffeine) was not associated with any change in endothelial performance. In the current study we intend to further examine the impact of caffeine on brachial endothelial function among healthy subjects & in patients with proven ischemic heart disease.

Background: Prior work (Chris, M. et al, Clinical Science 2005; 109, 55-60) has demonstrated that drinking a cup of coffee (80-100 mg of caffeine) an hour before endothelium-dependent FMD (flow-mediated dilatation) of the brachial artery, effects endothelial function in healthy adults subjects. This effect might be attributed to caffeine, given that decaffeinated coffee (<2 mg of caffeine) was not associated with any change in endothelial performance. In the current study we intend to further examine the impact of caffeine on brachial endothelial function among healthy subjects & in patients with proven ischemic heart disease. Aim: To evaluate the impact of 200 mg caffeine tablet intake (equivalent to 2 cups of coffee), compared to placebo on brachial endothelial function in healthy subjects & in patients with proven ischemic heart disease. Methods: Patients will be invited for two endothelial function tests 1 week apart. ECG, heart rate & blood pressure will be recorded at rest prior to each test. Following overnight fasting and discontinuation of all medications for ≥ 12 hours and absence of > 48 hour caffeine consumption, patients will receive 200 mg of caffeine tablets or placebo, in a double-blind, cross-over study design. An hour later the patient will undergo endothelium-dependent flow-mediated dilation (FMD) and endothelium-independent, nitroglycerin (NTG)-mediated vasodilation will be assessed non-invasively in the brachial artery, using a high resolution (15 MHz) linear array ultrasound. Prior to and after the FMD, blood will be drawn to test caffeine levels, adiponectin, CBC, electrolytes, CRP and lipids.

coronary disease, atherosclerosis, endothelial function, caffeine, cerebrovascular disease, prevention

Patients with prior history of coronary artery disease (CAD) (myocardial infarction, cerebrovascular accident, coronary angioplasty, S/p CABG operation) who will be given on the first day either caffeine of placebo tablet and 1-2 hours thereafter a brachial artery endothelial function testing (BRT) will be assessed for measuring the FMD. After 1 week the patients will come for a second BRT on placebo/caffeine tablets. If the patient received caffeine tablet the first BRT, he will be receiving placebo tablet the second week, however, if the patient received placebo the first BRT, a caffeine tablet will be given prior to the second BRT.

Patients with prior history of coronary artery disease (CAD) (myocardial infarction, cerebrovascular accident, coronary angioplasty, S/p CABG operation) who will be given on the first day either caffeine of placebo tablet and 1-2 hours thereafter a brachial artery endothelial function testing (BRT) will be assessed for measuring the FMD. After 1 week the patients will come for a second BRT on placebo/caffeine tablets. If the patient received caffeine tablet the first BRT, he will be receiving placebo tablet the second week, however, if the patient received placebo the first BRT, a caffeine tablet will be given prior to the second BRT.

Inclusion Criteria: Patients with documented ischemic heart disease Healthy subjects who are not heavy regular coffee drinkers Exclusion Criteria: Patients with unstable angina pectoris Patients with acute or chronic heart failure Patients with cardiac arrhythmia

The Heart Institute of the Sheba Medical Center and the Sackler Faculty of Medicine, Tel Aviv, Israel