|Year : 2017 | Volume
| Issue : 1 | Page : 1-2
Challenges of acute kidney injury after open heart surgery in Sub-Saharan Africa
Dr. Joe Nwiloh Heart Center, St. Joseph's Hospital, Adazi-Nnukwu, Anambra State, Nigeria
|Date of Web Publication||12-Dec-2017|
Dr. Joe Nwiloh Heart Center, St. Joseph's Hospital, Adazi-Nnukwu, Anambra State
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Nwiloh J. Challenges of acute kidney injury after open heart surgery in Sub-Saharan Africa. Niger J Cardiovasc Thorac Surg 2017;2:1-2
Chronic kidney disease (CKD) is a major public health challenge in most of Sub-Saharan Africa (SSA) with very limited or nonexistent capacity for renal replacement therapy (RRT). Even though the incidence of CKD in Africa is 3–4 times higher than in the Western World, RRT practice only ranges from <20 per million population (pmp) in most of SSA to 70 pmp in South Africa compared to 1228 pmp in the developed countries.,
Acute kidney injury (AKI) requiring dialysis (AKI-D), a dreaded complication after open heart surgery (OHS) significantly increases the risk for morbidity and mortality. This is particularly so in low resource countries seen in SSA where treatment options are very limited. The pathophysiology of AKI after OHS has been reported to include perioperative renal ischemia, reperfusion injury, cardiopulmonary bypass-induced hemolysis and pigment nephropathy, oxidative stress and inflammation. Moreover, these AKI patients even after recovery are likely to progress in the future to CKD compared to non-AKI patients. Although AKI reportedly occurs in 7%–40% of patients after OHS depending on the diagnostic criteria, AKI-D averages only 1%–2% of patients undergoing OHS., The present consensus guidelines for diagnosing AKI uses the Kidney Disease Improving Global Outcomes (KDIGO) criteria  which is defined using any of the following:
- ≥0.3 mg/dl (≥26.5 mmol/l) serum creatinine (SCr) increase from baseline within 48 h of surgery
- 50% SCr increase from baseline within 7 days of surgery or
- A decrease in urine output below 0.5 ml/kg/h for 6 h.
In a review of 602,134 patients undergoing OHS between 1999 and 2008 extracted from the “Nationwide Inpatient Sample” which collects data from approximately 20% of US community hospitals, AKI and AKI-D occurred in 7.7% and 0.8%, respectively. Overall inpatient mortality was 3.8% in 1999 and 3.3% in 2008 (unadjusted odds ratio (OR) 0.79, 95% confidence interval (CI): 0.71–0.88, and multivariate-adjusted OR 0.55, 95% CI: 0.49–0.62). Whereas mortality for the subgroup with AKI and AKI-D was 27.9% and 45.9% in 1999, it had decreased to 12.8% and 35.3% by 2008, respectively. Although there is paucity of data on AKI after OHS in SSA, a 2015 review of noncardiac surgical patients from Cameroun identified 17 (8.5%) of 201 patients with postoperative AKI based on KDIGO criteria. The surgeries were mainly obstetrics and gynecology, general and orthopedics. Three (17.6%) of the seventeen patients needed RRT but only one (33.3%) received it. The hospital mortality was 23.5% versus 1.6% (P = 0.008) for AKI and non-AKI groups, respectively. Another SSA AKI outcomes review of 41 studies from 1990 to 2014 comprising 3340 patients found that only 666 (63.9%) of 1042 children and 58 (32.5%) of 178 adults needing RRT actually received it. The observed overall AKI mortality in children and adults was 34% and 32% respectively versus 73.0% and 86.0% in patients who needed RRT but did not receive it. This higher mortality in AKI-D patients who did not receive it is understandable given the inability to effectively combat hyperkalemia, uremia, volume overload, and acidosis without RRT. Currently, obstacles to achieving sustainable dialysis programs in SSA, include inadequate infrastructures, dearth of trained nephrologists and ancillary staff, and lack of third-party reimbursement or government subsidies. Even for patients who survive AKI and later go on to develop end-stage renal disease (ESRD), their long-term outlook still remains bleak. The life expectancy of ESRD patients in Nigeria, for instance, is an average of 3–6 months, as majority cannot afford or sustain the cost of required 3 times weekly maintenance dialysis (personal communications). Given this background of limited access and affordability for elective maintenance RRT, urgent/emergency dialysis for AKI complicating OHS in a likely hemodynamically unstable patient can present a monumental challenge in this environment. In view of these severe handicaps, therefore, the goal should be preventing AKI if possible and the aphorism “An ounce of prevention is worth a pound of cure” would be most apt. Obialo  in this Journal's issue has enumerated several AKI preventive measures including correction of anemia while avoiding excessive perioperative allogenic blood transfusion, maintenance of adequate perfusion pressure on cardiopulmonary bypass and cardiac output. Several predictive risk models have also been proposed ,, to identify patients at risk for AKI. The Cleveland Clinic predictive risk score based on a review of 33,217 OHS cases operated at their Institution from 1993 to 2002 has been shown in comparative validation studies to be the most accurate ,, [Table 1]. Available RRT modalities as outlined by Obialo  include intermittent hemodialysis (IHD), continuous RRT (CRRT) or a hybrid. High volume peritoneal dialysis (HVPD) with a cycler is a viable alternative in resource-poor countries despite its limitations and risk of peritonitis. HVPD is currently the only available option at our heart center. Because of the high capital cost of acquiring dialysis machines, water treatment systems, ongoing repairs/maintenance, constant power supply, gravity-driven peritoneal dialysis is seen as more cost-effective and therefore more commonly used for AKI in most of SSA countries.,
In conclusion, with limited available therapeutic options in SSA, the use of validated predictive scores can serve as a crystal ball in identifying high-risk patients for AKI. Accurate prediction can enable preoperative optimization of high-risk patients and also allow the opportunity for referral to centers with the capacity to provide hemodialysis should it be required postoperatively. Incorporating established AKI preventive measures in clinical pathway plans could further help reduce risk in other OHS patients.
| References|| |
Naicker S. End-stage renal disease in Sub-Saharan Africa. Ethn Dis 2009;19(S1):13-5.
Bello B. Identifying the barriers to achieving sustainable dialysis programs in Sub-Saharan Africa: Nigeria as a reference point. J Nephrol Ther 2014;4:1-4, 186.
O'Neal JB, Shaw AD, Billings FT 4th
. Acute kidney injury following cardiac surgery: Current understanding and future directions. Crit Care 2016;20:187.
Dardashti A, Ederoth P, Algotsson L, Brondén B, Bjursten H. Incidence, dynamics, and prognostic value of acute kidney injury for death after cardiac surgery. J Thorac Cardiovasc Surg 2014;147:800-7.
Lenihan CR, Montez-Rath ME, Mora Mangano CT, Chertow GM, Winkelmayer WC. Trends in acute kidney injury, associated use of dialysis, and mortality after cardiac surgery, 1999 to 2008. Ann Thorac Surg 2013;95:20-8.
Kristovic D, Horvatic I, Husedzinovic I, Sutlic Z, Rudez I, Baric D, et al.
Cardiac surgery-associated acute kidney injury: Risk factors analysis and comparison of prediction models. Interact Cardiovasc Thorac Surg 2015;21:366-73.
Khwaja A. KDIGO clinical practice guidelines for acute kidney injury. Nephron Clin Pract 2012;120:c179-84.
Olowu WA, Niang A, Osafo C, Ashuntantang G, Arogundade FA, Porter J, et al.
Outcomes of acute kidney injury in children and adults in sub-Saharan Africa: A systematic review. Lancet Glob Health 2016;4:e242-50.
Obialo C. Acute kidney injury following cardiopulmonary bypass surgery. Niger J Cardiovasc Thorac Surg 2017;2:3-8. [Full text]
Malov AA, Borisov AS, Lomivorotov VV, Efremov SM, Ponomarev DN, Mukhoedova TV, et al.
Mortality prediction in patients with dialysis-dependent acute kidney injury after cardiac surgery with cardiopulmonary bypass. Heart Lung Circ 2014;23:325-31.
Mehta RH, Grab JD, O'Brien SM, Bridges CR, Gammie JS, Haan CK, et al.
Bedside tool for predicting the risk of postoperative dialysis in patients undergoing cardiac surgery. Circulation 2006;114:2208-16.
Thakar CV, Arrigain S, Worley S, Yared JP, Paganini EP. A clinical score to predict acute renal failure after cardiac surgery. J Am Soc Nephrol 2005;16:162-8.
Kiers HD, van den Boogaard M, Schoenmakers MC, van der Hoeven JG, van Swieten HA, Heemskerk S, et al.
Comparison and clinical suitability of eight prediction models for cardiac surgery-related acute kidney injury. Nephrol Dial Transplant 2013;28:345-51.
Olivero JJ, Olivero JJ, Nguyen PT, Kagan A. Acute kidney injury after cardiovascular surgery: An overview. Methodist Debakey Cardiovasc J 2012;8:31-6.
Callegari JG, Kilonzo KG, Yeates KE, Handelman GJ, Finkelstein FO, Kotanko P, et al.
Peritoneal dialysis for acute kidney injury in sub-Saharan Africa: Challenges faced and lessons learned at Kilimanjaro Christian Medical Centre. Kidney Int 2012;81:331-3.
Callegari J, Antwi S, Wystrychowski G, Zukowska-Szczechowska E, Levin NW, Carter M, et al.
Peritoneal dialysis as a mode of treatment for acute kidney injury in sub-Saharan Africa. Blood Purif 2013;36:226-30.
Thakar CV. Predicting acute kidney injury after cardiac surgery: How to use the “crystal ball”. Am J Kidney Dis 2010;56:605-8.