Acute Kidney Injury (AKI) is defined as an absolute increase in serum creatinine ≥0.3 mg/dl (≥26.4 μmol/l), a percentage increase in serum creatinine ≥50% (1.5-fold from baseline), or a reduction in urine output (documented oliguria < 0.5 ml/kg/hour for > 6 hours) S.creatinine which is considered the gold standard currently for diagnosis of AKI remains unchanged until 50% of kidney function falls down. It is affected by non-specific factors like diet, age, dehydration, muscle mass, gender, and drugs.

There were evidences of the association between AKI and acute coronary syndrome (ACS); First, AKI detection may be missed by cardiologists. Physicians tend to disregard mild or transient serum creatinine elevation during hospital stay for ACS, and they often attribute small serum creatinine increases to laboratory variations.

Cystatin C (CysC), a cystatin protease inhibitor, is less affected by non-specific factors. When glomerular filtration rate (GFR) decreases, CysC begins to increase.

CysC was recommended to be measured in addition to creatinine in GFR estimation.

Cysteine-rich protein 61 (Cyr61) is a cysteine-rich secretory protein that promotes cell proliferation, adhesion, chemotaxis, embryonic development and neovascularization . Previous studies have detected low expression level of Cyr61 in normal adult kidney and high expression of Cyr61 in ischemic rats and mice kidney, which suggests that Cyr61 may be a potential biomarker for diagnosis of AKI . CYR61 might possibly identify patients with more severe kidney injury, which would be very beneficial for early treatment of AKI after

Inclusion Criteria:

1. Age ≥ 18 years.
2. Informed consent
3. Patient with absolute increase in serum creatinine ≥0.3 mg/dl (≥26.4 μmol/l) or with percentage increase in serum creatinine ≥50% (1.5-fold from baseline)
4. Patient with reduction in urine output (documented oliguria < 0.5 ml/kg/hour for > 6 hours)
5. Patient with typical chest pain, ECG changes, Echocardiogram positive finding

Exclusion Criteria:

1. History of nephrectomy
2. patient with renal transplantation
3. patient with renal replacement therapy initiated before admission
4. patient with chronic kidney disease
5. patient on regular haemodialysis
6. patient known to be diabetic

Patient come to assuit university hospital with typical chest pain, ECG changes, Echocardiogram positive finding then develope absolute increase in serum creatinine ≥0.3 mg/dl (≥26.4 μmol/l), with percentage increase in serum creatinine ≥50% (1.5-fold from baseline) or with reduction in urine output (documented oliguria < 0.5 ml/kg/hour for > 6 hours)