Acute kidney injury requiring dialysis and in-hospital mortality in patients with chronic kidney disease and non–ST-segment elevation acute coronary syndrome undergoing early vs delayed percutaneous coronary intervention: A nationwide analysis

Background: Chronic kidney disease (CKD) is a well-known risk factor for coronary artery disease and is associated with poor outcomes following an acute coronary syndrome (NSTE-ACS). The optimal timing of an invasive strategy in patients with CKD and NSTE-ACS is unclear. Hypothesis: Timing of PCI in CKD patients will not affect the risk of mortality or incidence of dialysis. Methods: We queried the National Inpatient Sample database (NIS) to identify cases with NSTEMI and CKD. Patients who underwent percutaneous coronary intervention (PCI) day 0 or 1 vs day 2 or 3 after admission were categorized as early vs delayed PCI, respectively. The primary outcomes of the study were in-hospital mortality and acute kidney injury requiring hemodialysis (AKI-D). The secondary outcomes were length of stay and hospital charges. Baseline characteristics were balanced using propensity score matching (PSM). Results: After PSM, 3708 cases from the delayed PCI group were matched with 3708 cases from the early PCI group. The standardized mean differences between the 2 groups were substantially reduced after PSM. All other recorded variables were balanced between the 2 groups. In the early and delayed PCI groups, the incidence of AKI-D (2.5% vs 2.3%; P = 0.54) and in-hospital mortality (1.9% vs 1.4%; P = 0.12) was similar. Hospital charges and length of stay were higher in the delayed PCI group. Conclusions: The incidence of AKI-D and in-hospital mortality among patients with CKD and NSTE-ACS were not significantly affected by the timing of PCI. However, delayed PCI added significant cost and length of stay. A prospective randomized study is required to validate this concept.