Acute Decrease in Kidney Function After Acute Coronary Syndromes Predicts Future Bleeding and Cardiac Death

BACKGROUND: Coronary artery disease and renal failure are conditions with severe clinical impact. Current evidence indicates a close link between acutely impaired kidney function and adverse cardiovascular outcomes after percutaneous coronary intervention (PCI). In the current study, we sought to assess the impact of renal impairment in patients presenting with acute coronary syndromes (ACS) within 24 hours of admission on cardiovascular outcomes. METHODS: Between 1 January 2009 and 15 October 2012, we analysed data of 787 patients who presented with the diagnosis of ACS and underwent coronary angiography at the University Hospital Zurich. Blood samples for measurement of creatinine were obtained prior to PCI (T1) and after 12−24 hours (T2). Follow-up was by telephone interview at 30 days and a clinical visit at 1 year. Primary endpoints were major adverse cardiac and cerebrovascular events (MACCE) and/or bleeding events (classified as BARC, GUSTO or TIMI types), termed net adverse clinical events (NACE) when combined, at 30-day and 1-year follow-up. Further, possible predictors of acute kidney injury (AKI) within the first 24 hours after admission were identified. We assessed renal function by means of estimated glomerular filtration rate (GFR) according to the Cockcroft-Gault equation, and divided all patients into six groups according to the KDIGO classification of chronic kidney injury. Additionally, we assessed absolute changes in creatinine ≥0.3 mg/dl, according to the cut-off for the diagnosis of acute kidney injury. RESULTS: A total of 179 patients (24.7%) showed acute decreases in GFR class between T1 and T2. If acute kidney injury was defined as a change in creatinine levels of ≥0.3 mg/dl, a larger number of patients showed an acute decrease in kidney function (44.9%, n = 325). At 30 days, MACCE occurred in 4.3% of all patients (n = 31), whereas those with decreasing GFR showed significantly higher rates of MACCE than patients with stable kidney function (7.8 vs 3.1%, p < 0.05). The effect was mainly attributable to cardiac death. BARC and moderate GUSTO bleedings also were significantly more common in patients with decreasing GFR after 30 days. There were significantly more NACE in patients with a decrease in GFR (17.3 vs 7.3% in the group with stable kidney function, p < 0.05). Up to 1 year, MACCE occurred in 9% of all patients (n = 65), with significantly more MACCE in those with decreasing kidney function (13.4 vs 7.5%, p < 0.05). Similarly, both cardiac and noncardiac deaths were more common in patients with decreasing renal function (p < 0.05). Finally, at long-term follow-up, BARC 3/4/5 bleedings, mild to moderate GUSTO bleedings and major TIMI bleedings occurred more frequently with decreasing GFR (p < 0.05) as did NACE (27.4 vs 13.6%, p < 0.05). CONCLUSION: Decreasing GFR within 24 hours after admission for an ACS is significantly associated with cardiovascular and bleeding events at 30 days and 1 year.