Long Term Renal Outcomes and Mortality Following Persistent Renal Injury Among Myocardial Infarction Patients Treated by Primary Percutaneous Intervention

Background: Limited data are present on persistent renal impairment following acute
kidney injury (AKI) and long term renal outcomes among ST elevation myocardial
infarction (STEMI) patients. We evaluated the incidence and prognostic implications
of acute kidney disease (AKD), reduced kidney function for the duration of between 7
and 90 days after exposure to an AKI initiating event, as well as long term renal
outcomes among STEMI patients undergoing primary percutaneous coronary
intervention who developed AKI.

Methods: We retrospectively studied 225 consecutive STEMI patients who
developed AKI. Patients were assessed for the occurrence of AKD and long term
renal outcomes based on serum creatinine levels measured at 7 days/hospital
discharge and within 90-180 days of renal insult. Mortality was assessed at 90 days
and over a period of 1271 ± 903 days (range 2-2130) following renal insult.

Results: Progression to AKD occurred in 81/225 patients (36%) and was associated
with higher 90 day and long term mortality (p<0.001). Normalization of serum
creatinine to a level equal/lower than hospital admission level at 90 days from renal
insult occurred in 41% patients with AKD. New chronic kidney disease (CKD) was
diagnosed in 24%, while 35% demonstrated progression of preexisting CKD at 90
days from renal insult. In contrast, only 7% of patients without AKD had progression
of preexisting CKD, while in the rest serum creatinine remained stable.

Conclusion: Progression to AKD following an acute renal insult in STEMI is
frequent and associated with adverse long term renal outcomes.