The purpose of this study in humans with stable coronary artery disease (CAD) treatable by PCI (percutaneous coronary intervention) is to evaluate if dynamic physical exercise leads to an instantaneous improvement of coronary collateral function.

The existence of coronary collateral vessels and their benefit against cardiac events have been recognized for many years, but their functional capacity in response to physical exercise has partially remained elusive. Via endothelial shear stress, the fundamental stimulus for collateral development, exercise theoretically leads to collateral vasodilation and recruitment by an increase in heart rate and blood pressure during exercise. Moreover, the phenomenon of "walking through angina" indicates that collateral function and physical activity are related and their interaction is of clinical relevance.

The purpose of the present study in humans with stable coronary artery disease was to assess the instantaneous response of coronary collateral function to dynamic physical exercise.

Inclusion Criteria:

• Age more than or 18 years old
• 1- to 3-vessel coronary artery disease (CAD)
• Stable angina pectoris
• At least 1 stenotic lesion suitable for PCI
• Negative Allen-test
• Written informed consent to participate in the study

Exclusion Criteria:

• Patients admitted as emergencies
• Acute myocardial infarction
• Unstable CAD
• Q-wave myocardial infarction in the area undergoing CFI measurement
• CAD treated best by CABG
• Severe valve disease
• Pregnancy