Background: The combined influence of CKD and worsening renal function (WRF) on clinical outcomes in patients undergoing primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) has not been fully understood.
Methods: We analyzed 443 patients diagnosed with AMI who underwent primary PCI. Based on their estimated glomerular filtration rate (eGFR), they were classified into two groups: a high eGFR group (eGFR ≥ 45 mL/min/1.73 m2, n = 381) and a low eGFR group (eGFR < 45 mL/min/1.73 m2, n = 63). WRF was defined as an increase in serum creatinine levels ≥ 0.3 mg/dL above the admission value during the course of hospitalization. The primary end-point was set as all-cause mortality.
Results: WRF was observed in 88 patients (19.8%). The median follow-up duration was 769 (interquartile range 397-1314) days. The all-cause mortality rate was significantly lower in the high eGFR than in the low eGFR group (5.5 vs. 28.6%, respectively, at 1500 days, P < 0.001). In patients with WRF, the all-cause and cardiac mortality rates were significantly higher than in patients without WRF, and these results were consistent between the high and low eGFR sub-groups. Multivariate Cox proportional hazards model analysis showed that low eGFR and WRF remained independent predictors of all-cause mortality [(hazard ratio 2.61, 95% confidence interval 1.27-5.36, P = 0.009) and (hazard ratio 2.59, 95% confidence interval 1.34-5.01, P = 0.005), respectively].
Conclusions: Both eGFR at baseline and WRF were observed to be important predictors of mortality in patients with AMI undergoing primary PCI. WRF showed a significant effect on mortality even in patients with high eGFR.
Keywords: Acute myocardial infarction; Chronic kidney disease; Mortality; Worsening renal function.