Tag Archives: cardiac surgery

Acute Kidney Injury after Cardiac Surgery

Background: Renal dysfunction is one of the most common complications after cardiac surgery. The major concern is that despite advances in bypass techniques, intensive care and delivery of hemodialysis, mortality and morbidity associated with renal failure have not markedly changed in the last decade. The purpose of this work was to study the incidence of renal dysfunction after cardiac surgery, analyzing the possible causes, associated risk factors and treatment methods used.
Material and methods: In this prospective observational study we analyzed patients undergoing open-heart surgery between October 1, 2010 – December 15, 2010 at the Clinic of Cardiac Surgery Târgu Mureș. Blood urea nitrogen and creatinine level were recorded for all patients before and after surgery, patients age, sex, type of surgical intervention, length of cardiopulmonary bypass, and the degree of intraoperative hypothermia, hemodilution and postoperative hemodynamic function were noted.
Results: In this period 89 patients underwent cardiac surgery. Renal dysfunction developed in 20.2% of the patients and was more common in patients with complex surgery with prolonged cardiopulmonary bypass (p<0.0167), in patients with intraoperative hemodynamic instability. Other intraoperative factors, such as hemoglobin level lower than 8 g/dl (p=0.0103), postoperative hemodynamic dysfunction and use of vasoconstrictor agents also influenced the development of renal dysfunction.
Conclusions. Cardiac surgery is associated with a relative high incidence of renal dysfunction. Risk factors for this syndrome are varied and involve hemodynamic and inflammatory changes, but factors such as the body temperature and hemoglobin level during extracorporeal circulation could have a significant contribution.

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The Prognostic Value of AKIN and RIFLE Classifications in Acute Renal Failure Developing After Cardiac Surgery

Background: Renal dysfunction is common after cardiac surgery, ranging from minor changes in serum creatinine without clinical manifestations to frank anuria and severe metabolic dysfunction. In recent years two scores were developed to diagnose renal dysfunction. The aim of our study was to compare the prognostic value of these scores in acute renal failure associated with cardiac surgery.
Materials and methods: In our prospective clinical observational study we calculated and compared the AKIN (Acute Kidney Injury Network) and RIFLE (Risk, Injury, Failure, Loss, Endstage kidney disease) scores in 178 patients undergoing open heart surgery at the Clinic of Cardiovascular Surgery in Târgu Mureș, Romania, between October 1, 2010 and March 31, 2011, and studied the morbidity and mortality in patients with renal dysfunction in terms of these scores.
Results: According to AKI criteria, we identified 39 patients having high risk for developing renal injury (stage I) (with 16 cases more than with RIFLE criteria, class R), but we observed no differences in the number of renal dysfunction (28 patients) or renal failure (18 patients). The patients enrolled in high risk group according to AKI score, but not with RIFLE criteria, had a good outcome with diuretics and avoidance of nephrotoxic agents. Two patients needed renal replacement therapy, both of them were classified in the renal failure group. Mortality was higher in renal failure according to both RIFLE and AKI criteria.
Conclusions: AKI criteria are more sensitive in identifying patients at risk for renal injury, but the RIFLE criteria are more accurate in the estimation of postoperative morbidity and mortality.

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