Author + information
- Hitinder S. Gurm, MD⁎ (, )
- David Share, MD,
- Adam Greenbaum, MD and
- Mauro Moscucci, MD, MBA
- ↵⁎University of Michigan Health System, Division of Cardiovascular Medicine, University of Michigan Cardiovascular Center, 2A394, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109-5853
We welcome Drs. Kalra and Fenster's interest in our work delineating the association between renal function–based contrast dose and the risk of renal complications in patients undergoing percutaneous coronary intervention (1). They argued that in high-risk patients, and especially among patients with cardiogenic shock, the incidence of contrast-induced nephropathy (CIN) is unacceptably high, even when the ratio of contrast volume to creatinine clearance is <2, and invoked the need for “another formula to reduce the risk of CIN.”
The goal of our study was to define a simple strategy for contrast dosing, and as our study highlighted, there was no dose of contrast that is absolutely free of risk. The risk of renal dysfunction is determined by the baseline clinical characteristics of the patients, and in high-risk patients, the risk of CIN will be higher than that in lower-risk patients.
Currently, any deterioration of renal function following contrast administration is classified as CIN; however, some of these events are secondary to cholesterol embolism, and an additional unknown number of events, especially in cardiogenic shock, might be secondary to acute tubular necrosis. This may be one reason why it has been difficult to develop a simple formula for defining contrast dose in this subgroup of patients.
The relative contribution of contrast media to renal dysfunction in patients with shock remains unknown. Indeed, in the SHOCK (Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock) trial, the risk of renal failure was higher in patients in the medical arm compared with patients in the revascularization arm (2).
We agree that better strategies to reduce the incidence of renal dysfunction in these patients are urgently warranted. However, it is likely that these efforts will need to be multidimensional, and measures in addition to minimization of contrast will need to be explored. It may be possible to develop another formula that would help better define the safe limit of contrast for these high-risk patients, but in the absence of such a formula, creatinine clearance–based contrast dosing appears to be a simple strategy that may potentially reduce renal complications in all patients undergoing percutaneous coronary intervention.
- American College of Cardiology Foundation