Irreversible deterioration of estimated glomerular filtration rate in patients with acute myocardial infarction after primary percutaneous coronary intervention. 
Contrast-induced nephropathy is a possible complication after primary percutaneous coronary intervention (PCI) for acute myocardial infarction (MI).  Deterioration of renal function is reported to be generally reversible.  However, renal insufficiency worsens the prognosis for some patients with primary PCI.  We evaluated sequential changes in renal function before primary PCI and until the chronic phase.  We retrospectively studied 302 patients who had undergone PCI for acute MI.  Renal function was evaluated based on estimated glomerular filtration rates (eGFRs) measured at the following four points: before PCI, within 1 week after PCI, at discharge from the hospital, and 180-365 days after MI.  Patients were classified into the preserved eGFR group and the reduced eGFR group according to the median eGFR change from the basal level after PCI.  Changes in eGFR in the two groups had significantly different time courses.  In the preserved eGFR group, eGFR values during the chronic phase did not differ from the values obtained before PCI.  In contrast, eGFRs in the reduced eGFR group did not recover to pre-PCI basal levels, with the median decrease being 10.3 mL/min/1.73 m2.  The eGFR change after PCI was the strongest predictor of eGFR change during the chronic phase.  In the reduced eGFR group, incidence of major adverse cardiac events was significantly higher (logrank: p = 0.048), and the hazard ratio was 2.28 (95 % confidence interval 1.02-5.60).  A decline in eGFR after primary PCI for acute MI is not uncommon, and it appears to remain irreversible, even during the chronic phase.