Abstract
BACKGROUND: Contemporary quality initiatives emphasize minimizing contrast volume as a key modifiable factor to prevent acute kidney injury (AKI) following percutaneous coronary intervention (PCI). Left-digit bias is a cognitive bias where the leftmost digit of a number disproportionately influences decisions. This bias may unintentionally affect contrast administration when interpreting laboratory values like serum creatinine. Therefore, we aim to assess the impact of left-digit bias in serum creatinine level on contrast volume in PCI. METHODS: We analyzed patients undergoing PCI between January 2018 and December 2022 using the Japanese nationwide prospective multicenter registry. The primary outcome was PCI contrast volume. Left-digit bias was assessed by comparing contrast volume differences at specific creatinine thresholds (eg, 1.0 mg/dL and 2.0 mg/dL). AKI risks were calculated by a validated risk scoring system. RESULTS: Among 735 696 PCI procedures, the median contrast volume was 117 mL (interquartile range 85-157 mL). Analysis of average contrast volume revealed a sharp decrease at baseline creatinine levels above versus less than 1 mg/dL (mean difference, 2.2 mL [95% CI, 1.6-2.8]) and 2 mg/dL (4.7 [95% CI, 1.6-7.8]) but not at 3 mg/dL (-2.0 [95% CI, -10.0 to 6.0]). Despite differences at integer thresholds of creatinine, minimal variation across AKI risk levels suggests operators prioritize creatinine values over predicted AKI risk. CONCLUSIONS: Our study provides valuable insights into contemporary trends in contrast volume for PCI and identifies left-digit bias in creatinine interpretation affecting contrast administration. Formal risk stratification is essential to optimize contrast use for AKI prevention.