Left Atrial Strain for Predicting MACE in NSTEMI

Non-ST-elevation myocardial infarction (NSTEMI) carries significant short- and long-term risk of major adverse cardiovascular events despite advances in management. Current risk stratification relies on clinical scores such as GRACE 2.0 and conventional echocardiographic parameters including left ventricular ejection fraction (LVEF) and left atrial volume index (LAVI). These tools have limitations, as LVEF may remain preserved and LAVI mainly reflects chronic remodeling.

Left atrial (LA) reservoir strain assessed by two-dimensional speckle tracking echocardiography is a sensitive marker of left ventricular filling pressure and diastolic function. Reduced LA reservoir strain has been associated with adverse outcomes after NSTEMI, but data on its incremental prognostic value beyond established risk models remain limited.

This prospective observational study will assess whether LA reservoir strain independently predicts 6-month MACE and improves risk discrimination when added to the GRACE 2.0 score and conventional echocardiographic parameters in patients with NSTEMI.

Inclusion criteria

• Age > 18 years
• Confirmed diagnosis of NSTEMI according to current ESC/ACC guidelines
• Willingness to provide informed consent and complete 6-month follow-up
• Undergoing coronary angiography or revascularization during the index hospitalization

Exclusion criteria

• ST-elevation myocardial infarction (STEMI)
• Atrial fibrillation or other significant arrhythmia at presentation
• Moderate to severe valvular heart disease (especially mitral valve disease)
• Prior cardiac surgery or valve replacement
• Poor echocardiographic image quality precluding reliable strain analysis
• Chronic kidney disease on dialysis
• Known cardiomyopathy (hypertrophic, dilated, or infiltrative)
• Pregnancy
• Refusal to participate