Staffing challenges and subsequent withdrawal of funding.

The investigators of this study have found that after a heart attack, some heart cells rapidly age (become senescent) and release proteins that make the heart disease worse.

The investigators of this study would like to check for these aged-cell proteins in participants who have coronary artery bypass graft (CABG) surgery after a recent heart attack or to treat more stable heart disease.

The investigators will do this by taking blood samples and a sample of normally discarded heart tissue from each group of participants. This might help tell us who is at the highest risk of developing heart disease and how people recover from a heart attack.

The goal of this observational study is to compare the levels of aged-cell proteins in participants who have coronary artery bypass graft (CABG) surgery after a recent heart attack or to treat more stable heart disease.

The main questions it aims to answer are:

1. To identify if there is an increased in aged-cell proteins in participants who have had a myocardial infarction and are having CABG surgery, compared to participants who are having CABG surgery for more stable heart disease.
2. To establish if levels of these aged-cell proteins can predict outcomes for these patients, and if they correlate with other markers of heart disease.

The investigators will do this by taking blood samples and a sample of normally discarded heart tissue from each group of participants. This might help inform who is at the highest risk of developing heart disease and how patients recover from a heart attack.

Inclusion Criteria:

• Male and female patients aged 40 to 80 years old undergoing coronary artery bypass graft surgery for myocardial infarction or for stable angina.

Exclusion Criteria:

• patients with ST-elevation myocardial infarction requiring coronary angioplasty
• patients who have had previous cardiac surgery
• patients who have evidence of ongoing heart failure,
• a left ventricular ejection fraction of less than 30%
• need for pre-operative mechanical cardiac support.
• Individuals with pre-existing acute kidney injury
• Sepsis
• >Stage 4 chronic kidney disease

The study population are male and female patients undergoing CABG surgery. There will be 70 patients split between two groups of 35 patients each.

Group I will be patients who are undergoing coronary artery bypass graft surgery for recent Non-ST segment elevation myocardial infarction (NSTEMI), and Group II will be patients undergoing CABG for stable coronary artery disease