CardioExchange Archive

Hyperglycemia before coronary angiography raises the risk for contrast-induced, acute kidney injury (CI-AKI). My colleagues and I reached this conclusion in an investigation of the relationship between pre-procedural glucose levels and CI-AKI in 6,358 patients who underwent coronary angiography during hospitalization for MI. We found found a high risk for CI-AKI among those patients who had pre-procedural hyperglycemia but no known diabetes, even when the baseline renal function was normal.

While diabetes is a known risk factor for CI-AKI, it has not been clear until now that the risk extends to hyperglycemic patients without established diabetes. Importantly, elevated glucose levels are present in more than 40% of all patients hospitalized with MI, and more than half of these patients do not have known diabetes.

Some of the pathophysiologic mechanisms by which contrast can cause renal tubular injury (oxidative stress and free radical damage) are also activated in the setting of hyperglycemia. Thus, elevated pre-procedural glucose levels and IV contrast administration may deliver a “double hit” to kidney function.

While patients with elevated glucose levels but no known diabetes are not currently on clinicians’ radar screen as at risk for contrast-mediated nephropathy, their risk for kidney injury is as high as or even higher than those with established diabetes. They should, therefore, receive the same pre-angiography precautions and close post-procedural surveillance of renal function as other high-risk patients (e.g., those with known diabetes and CKD). Our findings raise the possibility that pre-procedural glucose control might reduce the risk for acute kidney injury, but this would need to be proven in a prospective clinical trial. Given the paucity of effective CI-AKI preventative strategies, this possibility merits further investigation.

Based on these results, I believe that all MI patients should have pre-angiography assessment of glucose levels to guide the employment of CI-AKI prophylactic measures and the intensity of post-procedural monitoring of renal function. What are your thoughts?