Contrast induced nephropathy (CIN) is a well-known possible complication of percutaneous coronary intervention (PCI) with an incidence varies from 3.3% to 14.5% in patients undergoing PCI.

Many previous randomized and non-randomized studies have shown very conflicting results regarding the use of ACE-Is prior to coronary angiography, and whether it decreases or increases the risk of CIN. The importance of this study is to help find an acceptable and reliable answer for the use of ACE-I/ARBs prior to cardiac catheterization.

This research aims to study the effect of withholding ACE-Is or ARBs on the incidence of contrast induced nephropathy in patients undergoing coronary angiography who have chronic kidney disease (GFR<60 ml/min/1.73 m2) and to help build evidence-based data and guidelines on the safety of continuing or withholding ACE-I/ARBs pre contrast administration.

The study design is a Randomized Control Trial; it will be done on two groups of patients. The two groups are group A (continue ACE-I/ARBs) and group B (withhold ACE-I/ARBs).

The study will be conducted at the cardiology units at An-Najah National University's hospital (NNUH) in Nablus, Palestine.

Study population includes chronic kidney disease patients taking ACE-I or ARBs therapy and are undergoing elective coronary angiography.

Patients who will meet the inclusion criteria and have none of the exclusion criteria will be enrolled in the trial when the appointment of their procedure is set.

They will be randomly divided into two groups; group A (continue ACE-I or ARBs therapy) and group B (withhold ACE-I or ARBs therapy)using block randomization, each block consists of four participants.

Patients in the continuation group will take their regular ACE-I/ARBs on the day of the angiogram. Patients in the discontinuation group will be withheld from their ACEI or ARBs 24 h before cardiac catheterization.

Inclusion Criteria:

1. At least one month of continuous therapy with an ACEI or an ARBs and
2. Undergoing elective coronary angiography and
3. Have CKD stage3-4 (15≤GFR<60 ml/min/1.73 m2).

Exclusion Criteria:

1. Acute STEMI within 2 weeks
2. NYHA class IV heart failure by history
3. Administration of contrast load within the previous 6 days
4. acute renal failure (ARF) preceding coronary angiography
5. potassium level more than 5.0 meq/l
6. GFR <15 ml/min/1.73 m2
7. previous percutaneous cardiac catheterization within one month
8. Acute pulmonary edema
9. hemodynamically instability
10. uncontrolled hypertension
11. combination ACEI and ARB therapy
12. Cardiogenic shock
13. Sepsis
14. pregnancy
15. Age below 18 year

Patients enrolled to the study were randomized into continuing or discontinuing (ACEI/ARBs) group. Care providers and investigators collected their data before and after the coronary angiography. The independent variable - continuing or discontinuing (ACEI/ARBs) - was coded into A or B groups, then data was sent to the outcomes assessor.