Antithrombin Ⅲ is a Novel Predictor for Contrast Induced Nephropathy After Coronary Angiography

Background/aims: Antithrombin Ⅲ (AT Ⅲ) is an important endogenous anticoagulant and has strong anti-inflammatory properties. Low ATⅢ activity is considered to be a predictor of poor outcomes in several conditions, including acute kidney injury after cardiac surgery. However, the association between the ATⅢ level and the occurrence of contrast induced nephropathy (CIN) has not been elucidated. In this study, our aim was to identify the potential predictive value of ATⅢ for CIN.

Methods: We enrolled a total of 460 patients who underwent coronary angiography (CAG) from January 2015 to December 2016 in coronary care units (CCU). ATⅢ activity in plasma collected before CAG was measured and <75% was considered low activity according to reference values. A cross-sectional study on CIN after CAG was conducted and the risk factors were analyzed. CIN was diagnosed according to the KDIGO guideline.

Results: Of these 460 patients undergoing CAG, 125 (27.17%) progressed to CIN. The incidence of CIN was significantly higher in patients with low ATⅢ activity compared to patients with normal ATⅢ activity (Pearson's chi-squared test P=0.002). As ATⅢ activity declined, the prevalence of CIN progressively increased, with the highest value (58.8%) in patients with an ATⅢ activity <60%. Moreover, the ATⅢ activity was significantly lower in CIN patients than in non-CIN patients (84.43±16.3% vs. 92.14±13.94%, P<0.001). After multivariable analysis, ATⅢ activity <75% remained a significant independent predictor of CIN (OR 2.207,95%CI [1.29-3.777]; P=0.004) as well as baseline serum creatinine (OR 1.009,95%CI [1.001-1.016]; P=0.026).

Conclusions: Patients with low ATⅢ activity had a higher risk of developing CIN after CAG. The initial ATⅢ activity may be a novel independent predictor for CIN.