Aki after cardiac surgery

1. CARDIAC SURGERY
ASSOCIATED
ACUTE KINEY INJURY

2. Overview
- Acute kidney injury (AKI) is a major medical problem after cardiac
surgery.
- Prevalence of cardiacsurgery-associated acute kidney injury (CSA-AKI)
is up to 30%, RRT cases (severe form) is 4%.
- CSA-AKI is independently associated with an increase of:
Short-term morbidities
Mortality (4-32% with AKI, 63% with RRT)
Costs of treatment

3. Pathogenesis
- The pathophysiology of CSA-AKI is complex, multifactorial ,
interrelated and synergistic
- CSA-AKI is the most common cause of AKI in intensive care unit (ICU)
after sepsis.
- The mechanism involved:
• Microembolization
• Neurohormonal activation
• Exogenous and endogenous toxins
• Metabolic,hemodynamic and inflammation factors
• Ischemia–reperfusion injury
• Oxidative stress

4. Cardio-pulmonary bypass
- Alter vasomotor tone, ↓renal parenchymal oxygen tension, ↓ the
renal perfusion pressure up to 30%, ↑the ischemia–reperfusion
injury.
- Microemboli (<40mcm) can damage renal capilaries directly.
- Releasing of free hemoglobin secondary to hemolysis cause renal
tubular damage, ↑ systemic vascular resistance, platelets and
coagulation activity dysfunction and increased mortality.

6. Risk factors:
The following risk factors are independently associated with AKI after
cardiac surgery:
- Preoperative renal dysfunction: eGFR <60 mL/min, creatinine
>2.1 mg/dL
- Preoperative cardiac dysfunction (preoperative use of an intra-
aortic balloon pump, NYHA IV, cardiogenic shock,↓LVEF,
congestive heart failure).
- Emergent surgery.
- Cross-clamp time and duration of CPB

7. Risk factors:
- Preoperative anemia, transfusion of RBC and haemodilution
during CPB
- Peripheral arterial disease.
- Reintervention.
- Insulin-requiring diabetes
- Elderly and female sex
- COPD
- Intraoperative use of aprotinin.

8. Surgery ‘s risk factors:
- “Valvular surgery, with or without coronary artery bypass graft
(CABG) are at a greater risk for the development of AKI compared
with those undergoing CABG alone”.
- CORONARY trial : off-pump CABG was associated with a lower rate of
mild AKI
- Veterans Affairs trial : off-pump CABG led to lower rates of 5-year
survival and event-free survival than on-pump CABG

9. Define and Diagnosis AKI
-More than 30 different
definitions for AKI
-Diagnostic scales use
variations in sCr values
and urinary output to
define the presence
and severity of AKI

11. RRT indications:
“With either IHD, or
CRRT or SLEDD, there
are limited data on
what is the ‘adequate’
intensity of dialysis.”

12. RRT targets:
No matter what technique is used, the following outcomes are predictable:
1. Continuous control of fluid status
2. Haemodynamic stability
3. Control of acid-base status
4. Ability to provide protein-rich nutrition while
achieving uraemic control
5. Control of electrolyte balance, including phosphate
and calcium balance
6. Prevention of swings in intracerebral water
7. Minimal risk of infection
8. High level of biocompatibility.

13. Predicted tools for RRT initiation:
-The Cleveland Clinic score
-The Mehta score
-The Simplified Renal Index (SRI) score

14. Prophylasis strategies

15. THANK YOU!