[Exercise capacity in coronary artery disease evaluated by continuous wave Doppler flowmetry]

Area of Science:

• Cardiology
• Diagnostic Imaging
• Exercise Physiology

Background:

• Coronary artery disease (CAD) diagnosis often relies on assessing myocardial ischemia and infarction.
• Exercise stress testing combined with imaging modalities can evaluate cardiac function under stress.

Purpose of the Study:

• To investigate the effects of exercise on peak aortic flow velocity (PFV).
• To determine the relationship between changes in PFV and the extent of myocardial ischemia or infarction.
• To assess the utility of PFV changes as a diagnostic marker for CAD.

Main Methods:

• Simultaneous continuous wave Doppler echocardiography and thallium-201 scintigraphy during supine bicycle exercise.
• Categorization of 83 CAD patients into four groups based on perfusion imaging (normal, ischemia, infarction, angina with infarction).
• Classification of PFV responses to exercise into three types (I, II, III) and correlation with ischemia/infarction extent.

Main Results:

• Normal controls showed a progressive increase in PFV with exercise (Type I).
• Patients exhibited three PFV response patterns: Type I (normal), Type II (initial increase, then plateau/decrease), and Type III (progressive decrease).
• Incidence of acute ischemia was significantly higher in Type II (79%) and Type III (75%) compared to Type I (25%).
• PFV response normalized (Type II/III to Type I) in 11/16 patients after percutaneous transluminal coronary angioplasty (PTCA), correlating with ischemia resolution.
• Maximum PFV change strongly correlated with the extent of ischemia and/or infarction (r = -0.50 to -0.80, p < 0.01).

Conclusions:

• Exercise-induced changes in PFV are closely related to the presence and extent of acute myocardial ischemia and/or infarction.
• PFV response patterns during exercise can serve as a valuable, non-invasive indicator of CAD severity.
• Doppler assessment of PFV during exercise, combined with scintigraphy, offers a comprehensive approach to diagnosing and evaluating CAD.