Cardiology MCQ 60: Contrast induced nephropathy

Q. Which of the following is incorrect regarding prevention of contrast induced nephropathy?

A. Preprocedure hydration with 0.9% NaCl is better than 0.45% NaCl

B. Low osmolar contrast media is better than iso-osmolar contrast media

C. Preprocedure use of N-acetyl cysteine is not recommended

D. Biplane angiography is useful in reducing the dose of contrast

Answer: B. Low osmolar contrast media is better than iso-osmolar contrast media

Explanation:

Contrast induced nephropathy (CIN)

Transient increase in creatinine by 0.5 mg/dl or 25% increase from baseline.

Occurs in 5% of patients following cardiac angiography.

It is non-oliguric, peak within 1 to 2 days and then return to baseline by 7 days but may rarely require chronic dialysis.

Risk factors:

DM

Pre-existing renal dysfunction

Multiple myeloma

Volume depletion

Other nephrotoxic drug therapy

The recommended maximum dose of contrast to limit CIN is 3 ml/kg (or 5 ml/kg divided by S. creatinine in patients with elevated baseline creatinine).

Strategies to minimize risk of CIN-

Smaller catheter is associated with lower amount of contrast per case.

Use of biplane angiography helps in minimizing the amount of contrast used for angiography.

Hydration protocol:

Isotonic saline 0.9%) is better than 0.45% saline.

0.9% NS 1 ml/kg/h starting 12 h before the procedure and continued for 12 h after the procedure.

2 ml/kg bolus infusion of NS 1 h before contrast administration, followed by an infusion of 1.5 ml/kg/h during the procedure and for 4 h thereafter.

Safety of contrast media used:

Iso-osmolar (Visipaque) > Low osmolar (Omnipaque) > High osmolar

The use Soda bicarbonate and NAC is not recommended.

Preprocedure statin use has been found to be associated with lower incidence of CIN and other complications of PCI.