Author + information
- Nishant Kalra, MD⁎ and
- Paul Fenster, MD
- ↵⁎Sarver Heart Center, University of Arizona, 1501 North Campbell Avenue, Room 4143, Tucson, Arizona 85724-5037
The observational study by Gurm et al. (1) showed that the ratio of contrast volume to creatinine clearance (CV/CCC) is a simple tool that can help reduce the risk of contrast-induced nephropathy (CIN) in patients undergoing percutaneous coronary intervention. The most important preventive measure is reducing the CV, and this article focused on defining the dose range that would optimize patient safety. However, the proposed formula has several shortcomings in high-risk patients.
Cigarroa et al. (2) in 1989 reported an empiric formula, 5 × weight (kg)/serum creatinine, that is known as the maximal acceptable contrast dose (MACD) for calculating the maximal dose of contrast that can be given safely. They validated their formula in 115 patients with serum creatinine ≥1.8 mg/dl undergoing coronary angiography and showed a rise in the incidence of CIN from 2% to 21% if CV exceeded the maximum recommended by MACD. Their formula is commonly used in catheterization laboratories but suffers from significant drawbacks. Many patients will develop CIN even when MACD is not exceeded. This formula does not specify a different safe dose limit for high-risk patients such as those with diabetes, heart failure, anemia, and cardiogenic shock. Cigarroa et al. (2) showed a rise in CIN from 2% to 6% in patients with diabetes receiving CV within MACD dose limits and a rise in CIN from 21% to 38% in patients with diabetes if CV exceeded MACD. Contrast dose recommended by CV/CCC is better than MACD at predicting CIN because CV/CCC formula takes age and sex into consideration in addition to the factors used in the MACD formula. However CV/CCC does not consider the high-risk features noted earlier.
Gurm et al. (1) concluded that a “contrast dose on the basis of CCC with a planned CV restricted to <2 × CCC might be valuable in reducing the risk of CdIN.” In their overall population, this CV was associated with an incidence of CIN of <2%. However, this CV is associated with an incidence of CIN of 4% in patients undergoing percutaneous coronary intervention for ST-segment elevation myocardial infarction (Fig. 3), 23% for patients in cardiogenic shock (Fig. 3), and 4% to 6.5% in patients with a glomerular filtration rate <60 ml/min (Fig. 4). Clearly, for these high-risk patients, another formula is necessary to reduce the risk of CIN.
- American College of Cardiology Foundation