Severe acute kidney injury following cardiac surgery: short-term outcomes in patients undergoing continuous renal replacement therapy (CRRT)
Acute kidney injury (AKI) represents a major complication of cardiac surgery. Our aim was to evaluate, in patients undergoing continuous renal replacement therapy (CRRT) for cardiac surgery-associated AKI (CS-AKI), prognostic factors related to in-hospital survival and renal function recovery to independence from RRT.
We conducted a retrospective analysis in patients with severe CS-AKI who underwent CRRT for at least 48 h. The sequential organ failure assessment (SOFA) score was calculated on a daily basis to evaluate illness severity throughout the intensive care unit (ICU) stay.
In 264 patients (age 66.4 ± 11.7 years, 192 males), 30-day survival was 57.6 % while survival to discharge from the hospital was 40.5 %. Renal function recovery occurred in 96.3 % of survivors and in 13.4 % of non-survivors (p < 0.001). Multivariate analysis selected advancing age, oliguria, sepsis and the highest level of SOFA score within the first week of CRRT (SOFA-max) as independent prognostic factors for failure to recover renal function. Female gender was associated with a higher probability of survival, while higher serum creatinine at the start of CRRT, oliguria, sepsis and SOFA-max were independently associated with mortality. The subgroup of patients with a day-1 SOFA score above the median (≥10) showed a lower probability of survival and a lower cumulative incidence of renal function recovery.
In a selected population of patients with severe CS-AKI requiring RRT, short-term outcomes appear strongly associated with the worst grade of illness severity during the first week of CRRT, thus reflecting the sequential occurrence of additional major complications during ICU stay. Renal function recovery and in-hospital survival appear mutually linked, sharing oliguria, sepsis and SOFA score as the main determinants of both outcomes.
KeywordsAcute kidney injury Cardiac surgery CRRT CVVH CVVHDF Renal function recovery
Conflict of interest
All procedures performed in this retrospective study, involving human participants, were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Formal consent was not required for this type of study.
Informed consent was obtained from all individual participants included in the study.
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