Asymptomatic left main coronary artery disease and silent myocardial ischemia
F A Shawl1, P K Chun, M L Mutter
1Cardiology Service, Walter Reed Army Medical Center, Washington, D.C.
Insights
Asymptomatic left main coronary artery disease (ALMD) is challenging to study but may be common. Treadmill tests reveal significant ST depression in most ALMD patients, similar to symptomatic disease.
Area of Science:
- Cardiology
- Vascular Medicine
- Diagnostic Imaging
Background:
- Asymptomatic left main coronary artery disease (ALMD) presents diagnostic and prognostic challenges.
- Epidemiological and postmortem data suggest ALMD may be more prevalent than clinically recognized.
- Limited data exists on the natural history and detection of ALMD.
Purpose of the Study:
- To investigate the characteristics and diagnostic findings of asymptomatic left main coronary artery disease (ALMD).
- To compare treadmill test (TMT) results between asymptomatic (ALMD) and symptomatic (SLMD) patients with left main coronary artery disease (LMD).
- To evaluate left ventricular function in patients with ALMD.
Main Methods:
- Retrospective review of 89 consecutive patients with left main coronary artery disease (LMD, ≥50% stenosis).
- Categorization into asymptomatic (ALMD, 10 patients) and symptomatic (SLMD, 79 patients) groups.
- Analysis of treadmill test (TMT) results, electrocardiogram (ECG) abnormalities, ejection fraction (EF), and left ventricular end-diastolic pressure (LVEDP).
Main Results:
- Ten patients (11%) were identified as asymptomatic (ALMD), all male, with a mean age of 53.
- Treadmill tests showed significant ST depression (≥2 mm) in 70% of ALMD patients within 9 minutes.
- Left ventricular ejection fraction and contractile patterns were normal in ALMD patients, but LVEDP was abnormal in 70%.
Conclusions:
- Asymptomatic left main coronary artery disease (ALMD) patients exhibit significant exercise-induced ischemia on TMT, comparable to symptomatic patients.
- Despite normal ejection fraction, diastolic dysfunction may be present in ALMD.
- Further research is needed to understand the prognosis and optimal management of ALMD.
Abstract:
Gathering data on the prognosis, detection, and natural history of asymptomatic left main coronary artery disease with silent myocardial ischemia is difficult. Epidemiologic studies of unexpected death and postmortem studies on silent myocardial infarction suggest this entity to be common. We reviewed 89 consecutive patients with left main coronary artery disease (LMD), defined as 50% or greater reduction of luminal diameter. Of this group, 10 patients (11%) were asymptomatic (ALMD) and 79 patients (88%) were symptomatic (SLMD). All 10 ALMD patients were men, with a mean age of 53 years (range 40 to 65). Treadmill tests (TMT) were performed for: ECG abnormalities six; pre-jogging evaluation two; risk factor evaluation two. The TMT within 9 minutes showed 2 mm or greater ST depression in seven (70%) and 1 to 2 mm in three (30%). Similar TMT results were obtained in the SLMD group, although two patients had negative responses. The degree of stenosis of the left main coronary artery and the frequency of three-vessel disease were similar in both groups. The ejection fraction (EF) and contractile pattern of the left ventricle (LV) were normal in all 10 ALMD patients, but the left ventricular end-diastolic pressure (LVEDP) was abnormal in three (70%). In the SLMD group, 51 (64%) had an abnormal ejection fraction, 50 (65%) had wall motion abnormalities, and 25 (32%) had an abnormal LVEDP.
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