EXERCISE TESTING AND LEFT MAIN CORONARY ARTERY DISEASE: EXPERIENCE WITH 57 PATIENTS

Area of Science:

• Cardiology
• Diagnostic Imaging
• Exercise Physiology

Background:

• Critical stenosis of the left main (LM) coronary artery poses a significant risk.
• The diagnostic utility of exercise stress testing in patients with suspected LM disease requires further elucidation.

Purpose of the Study:

• To analyze the results of multistage treadmill tests (TMT) in patients with critical left main coronary artery (LMCA) stenosis.
• To determine the sensitivity and specificity of TMT in detecting ischemia in this patient population.
• To identify predictors of exercise test positivity and severity of LM lesions.

Main Methods:

• Retrospective analysis of TMT results from 57 patients with critical (>= 50%) LMCA stenosis.
• Evaluation of ST segment depression, exercise tolerance, heart rate, blood pressure, and arrhythmias during TMT.
• Correlation of TMT findings with the extent of coronary artery disease.

Main Results:

• TMT was positive for ischemia in 89% of patients, with 70% showing a strongly positive response (>= 2 mm ST depression).
• Early ST segment depression in stages I and II of the Bruce protocol was observed in a significant proportion of patients, often without chest pain.
• Limited exercise tolerance and exercise-induced hypotension were noted, with arrhythmias occurring in 10% of patients.

Conclusions:

• Treadmill testing is a valuable tool for diagnosing ischemia in patients with LMCA stenosis, rarely yielding negative results.
• An early, strongly positive TMT response, particularly with ST depression in early stages, is highly suggestive of LM disease.
• Exercise-induced hypotension is uncommon, but limited exercise tolerance and early ST depression may predict the severity of LM lesions.