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Updated: Aug 10, 2026
Myocardial Infarction and Functional Outcome Assessment in Pigs
Published on: April 25, 2014
Effect of the stenosis location and severity on left ventricular function after single-vessel anterior wall
E Kachi1, H Yoshino, A Watanuki
1Second Department of Internal Medicine, Kyorin University School of Medicine, Tokyo, Japan.
Insights
The location of the infarct-related lesion (IRL) significantly impacts left ventricular (LV) function recovery after anterior wall myocardial infarction. Proximal lesions (CASS No. 12) show delayed recovery and chamber enlargement, unlike distal lesions (CASS No. 13).
Area of Science:
- Cardiology
- Cardiovascular Research
- Clinical Medicine
Background:
- Acute anterior wall myocardial infarction can impair left ventricular (LV) function.
- The infarct-related lesion (IRL) location and degree of stenosis are critical factors in recovery.
Purpose of the Study:
- To investigate how IRL location and stenosis severity affect LV function post-myocardial infarction.
- To differentiate functional outcomes based on proximal (CASS No. 12) versus distal (CASS No. 13) IRLs and stenosis severity.
Main Methods:
- Ninety patients with first anterior wall myocardial infarction underwent coronary angiography (CAG) acutely and at 1 month.
- Patients were categorized by IRL location (proximal CASS No. 12 vs. distal CASS No. 13) and 1-month stenosis severity.
- LV function was assessed using total wall motion index (TWMI) and fractional shortening (FS) at baseline, 1 month, and 1 year.
Main Results:
- Proximal lesions (CASS No. 12) were associated with reduced TWMI and increased LV dimensions compared to distal lesions (CASS No. 13).
- Patients with mild stenosis showed functional improvement, while those with severe stenosis did not.
- IRL location (CASS No. 12), initial low TIMI flow, and severe 1-month stenosis independently predicted poor LV function.
Conclusions:
- Proximal IRLs (CASS No. 12) with severe residual stenosis lead to delayed LV functional recovery and chamber enlargement.
- Distal IRLs (CASS No. 13) preserve LV function well, irrespective of residual stenosis severity.
Background:
The purpose of the current study was to determine how the location of the infarct-related lesion (IRL) and the degree of stenosis during the acute and chronic phases of infarction might affect left ventricular (LV) function in patients with acute anterior wall myocardial infarction.
Methods:
Ninety consecutive patients with a first single-vessel anterior wall myocardial infarction (male/female ratio 75:15, mean age 60+/-9 years) underwent coronary angiography (CAG) immediately and 1 month after infarction. Patients were grouped according to IRL location (proximal [Coronary Artery Surgery Study (CASS) No. 12] or distal [CASS No. 13] to the first diagonal branch of the left anterior descending artery) and according to the severity of stenosis at 1 month (severe stenosis [IRL >75%] and mild stenosis [IRL < or =75%]). At the time of infarction and 1 month and 1 year after infarction, total wall motion index (TWMI), left ventricular end-diastolic dimension (LVDd), left ventricular end-systolic dimension (LVDs), and fractional shortening (FS) were determined.
Results:
TWMI was greater and FS was lower for CASS No. 12 lesions than for CASS No. 13 lesions. CASS No. 12 lesions were associated with a greater LVDd at 1 year and a greater LVDs throughout 1 year of observation. The patients with mild stenoses had significant improvements in TWMI and FS over time, whereas those with severe stenoses showed no improvement. Multivariate analysis showed that the independent factors predicting left ventricular function were IRL location at CASS No. 12, initial TIMI 0-1 flow in the IRL at emergency coronary artery graft, and the presence of a severe stenosis at 1 month.
Conclusions:
In patients with severe stenoses at 1 month at CASS No. 12, left ventricular functional recovery is delayed and the left ventricular chamber is enlarged. In patients with CASS No. 13 lesions, left ventricular function is preserved well, regardless of the severity of residual stenosis.
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