Optimal time for catheterization in NSTE-ACS patients with impaired renal function: insights from the ABOARD Study

Background: To assess the impact of impaired renal function (IRF) and timing of catheterization (immediate versus delayed intervention) on outcomes in intermediate/high risk NSTE-ACS patients.

Methods: We performed a post-hoc analysis of the randomized ABOARD population to compare 1) patients with vs. without IRF and 2) the two intervention strategies in patients with IRF. A creatinine clearance <60 mL/min defined IRF. The primary endpoint was the in-hospital peak troponin I value; the secondary endpoints were a) the composite of death, myocardial infarction, urgent revascularization or recurrent ischemia (death/MI/UR/RI) and b) STEEPLE major bleeding (MB) at 1-month follow-up.

Results: Among the 345 patients, 75 (21.7%) had IRF. Patients with IRF were older, had more comorbidities and were at higher cardiovascular risk. Radial catheterization was predominant (84%). Among IRF patients, 37 (49%) and 38 (51%) patients were randomized to an immediate and delayed strategy, respectively. The primary and secondary endpoints rates were not different for the two comparisons. IRF was associated with more death (5.3% vs. 1.1%, p=0.043) and non-CABG MB (9.3% vs. 2.2%, p=0.001). In patients with IRF, a delayed strategy was associated with more recurrent ischemia (28.9% vs. 8.1%, p=0.021). Absence of clopidogrel pretreatment, insulin therapy and left main culprit lesion were independently associated with death/MI/UR/RI, while age and CABG surgery were related with MB.

Conclusion: IRF is associated with worse outcomes in NSTE-ACS patients. The primary results of the ABOARD study apply also to patients with IRF in which the timing of catheterization does not impact hard outcomes.