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Effect of adenosine on coronary blood flow and its use as a diagnostic test for coronary artery disease
J D Ogilby1, J Heo, A S Iskandrian
1Philadelphia Heart Institute, Presbyterian Medical Center, PA 19104.
Insights
Myocardial perfusion imaging effectively diagnoses coronary artery disease by detecting blood flow differences. However, myocardial ischemia is not always required for diagnosis, even with perfusion abnormalities during adenosine stress testing.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Physiology
Background:
- Myocardial perfusion imaging (MPI) during adenosine-induced vasodilation is a sensitive diagnostic tool for coronary artery disease (CAD).
- Perfusion defects typically indicate heterogeneous coronary blood flow between normal and diseased artery territories.
- Myocardial ischemia, while a concern, can arise from subendocardial hypoperfusion or coronary artery steal phenomena.
Purpose of the Study:
- To evaluate the diagnostic utility of MPI in identifying coronary artery disease.
- To investigate the relationship between perfusion abnormalities and the occurrence of myocardial ischemia.
- To determine if myocardial ischemia is a prerequisite for diagnosing CAD with adenosine stress testing.
Main Methods:
- Utilized myocardial perfusion imaging with adenosine as a stress agent.
- Assessed perfusion defects and correlated them with coronary artery disease status.
- Examined clinical and experimental evidence of myocardial ischemia, including ST-segment, wall motion, hemodynamic, metabolic, and coronary blood flow responses.
Main Results:
- MPI demonstrates high sensitivity in diagnosing coronary artery disease.
- Perfusion abnormalities are primarily linked to heterogeneous coronary blood flow.
- Myocardial ischemia, evidenced by various physiological markers, can occur but is not consistently present in all diagnosed CAD cases.
Conclusions:
- Adenosine stress testing with MPI is a valuable method for diagnosing coronary artery disease.
- Perfusion abnormalities on MPI can be present even in the absence of definitive signs of myocardial ischemia.
- Myocardial ischemia is not a mandatory finding for the diagnosis of coronary artery disease using this imaging modality.
Abstract:
Myocardial perfusion imaging during adenosine induced coronary hyperaemia is a highly sensitive method for diagnosing coronary artery disease. Most perfusion defects reflect heterogeneity in coronary blood flow in the territories of normal and diseased coronary arteries. Myocardial ischaemia can occur, however, due to subendocardial hypoperfusion and coronary artery steal. Evidence for myocardial ischaemia is more difficult to document in clinical than in experimental studies, and includes abnormalities in the ST segment, wall motion, haemodynamic variables, metabolism, and coronary blood flow responses. Using these indices, myocardial ischaemia may occur in some patients with coronary artery disease but it is not a prerequisite for the development of perfusion abnormalities and for the diagnosis of coronary artery during adenosine stress testing.