AIM: Higher contrast volume during PCI leads to higher nephrotoxicity
During primary percutaneous coronary intervention (PCI) for STEMI, higher contrast volume is associated with higher rates of contrast-induced nephropathy (CIN) and mortality, according to an article in the Feb. 3 issue of the Annals of Internal Medicine.

Giancarlo Marenzi, MD, and colleagues from the University of Milan in Italy investigated the association between absolute and weight- and creatinine-adjusted contrast volume, CIN incidence and clinical outcome in the era of mechanical reperfusion of STEMI.

The researchers examined 561 consecutive patients with STEMI, who were undergoing primary PCI. For each patient, they calculated the maximum contrast dose, according to the formula (5 x body weight [kg])/serum creatinine, and assessed the contrast ratio, defined as the ratio between the contrast volume administered and the maximum dose calculated. An increase in serum creatinine of more than 25 percent from baseline was defined as CIN.

The investigators found that 20.5 percent of patients developed CIN. In-hospital mortality was higher among patients with CIN than those without CIN (21.4 vs. 0.9 percent).

Marenzi wrote that the maximum contrast dose was exceeded in 23 percent of patients. Patients who received more than the maximum contrast dose (contrast ratio >1) had a more complicated in-hospital clinical course and higher mortality rate (13 vs. 2.8 percent) than did patients with a contrast ratio less than one. Development of CIN was associated with both contrast volume and contrast ratio.

The authors acknowledged that a limitation to their study was that the observed association between contrast volume and outcomes took place in a single center and could be due to co-morbid conditions, disease severity or an unknown factor. Also, they said that it is unclear whether the worse outcomes were due to the contrast or whether unmeasured aspects of disease severity led to both the need for more contrast and the worse outcomes.

The authors concluded that further study is needed to determine whether limiting contrast volume would improve patient outcome.

Centro Cardiologico Monzino, Institute of Cardiology and the University of Milan funded the study.