Contrast Induced Nephropathy is an acute renal insufficiency defined as a 25% or 0.5 mg/dl increase over the baseline of the serum creatinine level 24 h to 72 h after intravascular administration of a contrast agent.

Contrast Induced Nephropathy has been introduced an important complication after coronary angiography and Percutaneous Coronary Intervention .

The development of Contrast Induced Nephropathy after Percutaneous Coronary Intervention is associated with poor clinical outcomes including prolonged hospitalization, increased costs, increased rates of end-stage renal failure, myocardial infarction, repeat revascularization, and short- and long-term mortality.

Contrast Induced Nephropathy follows decreased renal perfusion and administration of nephrotoxic medications as the third most common cause of renal insufficiency during hospitalization.

Patients with acute coronary syndrome have a 3-fold higher risk of developing Contrast Induced Nephropathy .Therefore ,predicting contrast nephropathy and initiating therapeutic preventive strategies are very important.

Red Blood Cell Distribution Width is a quantitive marker of the variability on size of erythrocyte.

It is a routine assay of Complete Blood Count that doesn't require an additional cost, that is calculated by dividing the standard deviation of the mean cell size by the Mean Corpuscular Volume of the red cells and multiplying by 100 to convert to a percentage.

Normal range of Red Blood Cell Distribution Width 11-16%. Increased Red Blood Cell Distribution Width means increased variability in red blood cell size owing to ineffective erythrocyte production, which is associated with indices of inflammation and pro-inflammatory cytokines such as interleukin-6 .

On the other hand, suggested mechanisms underlying Contrast Induced Nephropathy include cytotoxic effects, factors that affect renal hemodynamic, and regional hypoxia.

Inclusion Criteria:

Consecutive patients who underwent percutaneous coronary intervention either elective or emergency.

Exclusion Criteria:

1. End stage renal disease with glomerular filtration rate less than 30 ml/1.73.
2. Patient known allergy to contrast agents.
3. Left ventricular ejection fraction below 30%.
4. Presence of infection
5. A recent history of contrast administration in the previous month.
6. Patient known to have thyroid disease.
7. History of malignancy.
8. Patient known to have Autoimmune disease.
9. Decompensated liver cirrhosis
10. Cardiogenic shock.
11. Anemia

patients who underwent percutaneous coronary intervention