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Detection of critical coronary lesions with treadmill exercise testing: fact or fiction?
Insights
Treadmill exercise testing can help identify critical coronary artery disease, but S-T segment depression alone is not definitive. Early ischemic changes during exercise improve diagnostic accuracy for these serious coronary lesions.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Exercise Physiology
Background:
- Critical coronary lesions, defined as left main coronary artery obstruction or combined proximal left anterior descending and circumflex artery narrowing, pose significant risks.
- Accurate identification of critical coronary lesions is crucial for timely intervention and improved patient outcomes.
Purpose of the Study:
- To evaluate the efficacy of treadmill exercise testing in identifying patients with critical coronary lesions.
- To assess the diagnostic value of S-T segment depression magnitude and onset time in detecting critical coronary artery disease.
Main Methods:
- The study compared treadmill exercise test results in 25 patients with critical coronary lesions and 50 patients with other coronary artery lesions.
- Evaluated S-T segment depression (degree and time of onset) and correlated findings with the presence and severity of coronary artery disease, including triple vessel disease.
Main Results:
- Significant S-T segment depression (≥2 mm) was more frequent in critical lesion groups (82% left main, 71% left main equivalent) than others (36%), but lacked specificity.
- Early ischemic changes (within 3 minutes) were significantly more common in critical lesion groups (63% left main, 35% left main equivalent) compared to other lesions (6%).
- Triple vessel disease was more prevalent in patients with critical lesions (55-71%) versus those with other lesions (10%).
Conclusions:
- S-T segment depression of ≥2 mm alone has low specificity for identifying critical coronary lesions.
- Incorporating the time of onset of ischemic changes enhances the diagnostic utility of treadmill exercise testing for critical coronary artery disease.
- Treadmill exercise testing, especially when considering early ischemic changes, aids in evaluating patients for critical coronary lesions but does not provide a definitive diagnosis.
Abstract:
This study was designed to determine whether treadmill exercise testing could identify patients with critical coronary lesions. Critical lesions were defined as obstruction of the left main coronary artery or concomitant narrowing of the left anterior descending and circumflex coronary arteries proximal to any major branches. The time of onset and degree of S-T segment depression were evaluated in 25 patients with critical lesions and in 50 patients with other types of lesions. S-T segment depression of 2 mm or more was present in 82 percent of patients with left main coronary disease and in 71 percent of patients with left main coronary equivalent lesions (both P less than 0.02 when compared with 36 percent of patients with other lesions). However, half of the 37 patients with this degree of S-T segment depression had noncritical lesions. Ischemic changes appearing in the first 3 minutes of exercise were seen in 63 percent of patients with left coronary disease and 35 percent of the patients with left main coronary disease equivalent lesions (P less than 0.001 and P less than 0.002, respectively, when compared with only 6 percent of patients with other lesions). The incidence of triple vessel disease was significantly greater in patients with critical lesions (55 percent in patients with left main coronary disease and 71 percent in those with the left main coronary equivalent lesions versus 10 percent in those with other lesions) (P less than 0.01). S-T segment depression of 2 mm or more is not a good indicator of critical coronary lesions because it has a low level of specificity. Consideration of the time of onset of ischemic changes adds to its usefulness, but it does not permit a definitive diagnosis in individual patients.