Novel risk scoring for pre-procedural prediction of contrast-induced nephropathy and poor long-term outcomes among patients with chronic total occlusion undergoing percutaneous coronary intervention

Contrast-induced nephropathy (CIN) is a known complication of percutaneous coronary intervention (PCI). We aimed to develop a simplified risk scoring system based upon pre-procedure characteristics for predicting CIN and poor long-term outcomes in patients with chronic total occlusion (CTO) undergoing PCI. We prospectively enrolled 629 consecutive patients with CTO who were scheduled to undergo PCI. The patients were randomized in a 3 : 2 ratio to create a training ( n = 356) and a validation cohort ( n = 273). The primary endpoint was CIN, which was defined as an absolute increase in serum creatinine (SCr) ≥0.5 mg/dL over baseline within 48–72 h after contrast medium exposure. The incidences of CIN in the training and validation dataset were 2.8 and 2.6%, with a significant trend across increasing risk score values (all P 1.5 mg/dL), showed good discriminating power in both the training ( C -statistic = 0.838) and the validation dataset ( C -statistic = 0.876). In addition, on log-rank analysis, patients with high-risk scores exhibited a worse survival rate ( P < 0.001) or major adverse clinical events ( P = 0.002) than patients with low-risk scores. Among patients with CTO undergoing PCI, the present simple pre-procedural risk score showed excellent predictive ability for identifying patients at high risk of CIN and poor long-term outcomes, thus, allowing the interventional team to make adequate adjustments to the procedures.