RCIS Cardiac Catheterization Techniques and Contrast Media

Question 1

Which contrast agent property is most responsible for contrast-induced nephropathy (CIN)?

Accepted Answer

High osmolality and viscosity causing renal tubular injury and vasoconstriction

Answer

Iodine content causing allergic nephritis

Answer

Gadolinium chelation affecting tubular cells

Answer

Low molecular weight causing rapid glomerular filtration

Question 2

What is the standard pre-medication protocol for a patient with a prior contrast allergy undergoing elective catheterization?

Accepted Answer

Prednisone at 13, 7, and 1 hour before plus diphenhydramine 1 hour before

Answer

Antihistamine alone 1 hour before procedure

Answer

Pre-loaded epinephrine syringe only

Answer

No premedication needed if prior reaction was mild urticaria

Question 3

The Cigarroa formula for maximum safe contrast dose is calculated as:

Accepted Answer

5 cc × body weight (kg) ÷ serum creatinine

Answer

1 mL per kg body weight

Answer

3 mL/kg up to 300 mL total

Answer

2 mL/kg regardless of renal function

Question 4

Iso-osmolar contrast agents such as iodixanol differ from low-osmolar agents primarily by:

Accepted Answer

Having osmolality equal to blood (~290 mOsm/kg), reducing osmotic stress on vessels and tubules

Answer

Lower iodine concentration per mL

Answer

Not requiring renal excretion for elimination

Answer

Being gadolinium-based rather than iodine-based

Question 5

A patient develops urticaria and bronchospasm during contrast injection — what is the first-line treatment?

Accepted Answer

Epinephrine 0.3–0.5 mg IM or IV

Answer

IV diphenhydramine and observation

Answer

IV corticosteroids

Answer

Discontinue contrast and monitor vital signs

Question 6

The primary mechanism by which IV hydration prevents contrast nephropathy is:

Accepted Answer

Increasing urine output to flush contrast through the kidneys, reducing tubular exposure time

Answer

Diluting contrast concentration in the tubules

Answer

Alkalinizing the urine to neutralize iodine toxicity

Answer

Reducing the osmolality of the delivered contrast agent