Case 8: What is the risk for developing ARF after surgery?

Preoperative Care of Patients with Kidney Disease
Author: V. Dimov, M.D., Department of General Internal Medicine, Cleveland Clinic

76 yo male with DM2 on insulin, COPD, HTN, CKD is diagnosed with severe triple-vessel CAD and is here for preoperative evaluation for CABG. Serum creatinine has been 1.4-1.6 mg/dL for the last 2 years. The patient and his family are worried about worsening of his kidney function after the surgery.

What is his risk for developing ARF after cardiac surgery?

You can use a clinical score to predict the risk for ARF after cardiac surgery (Thakar et al, 2005).

Risk Factor	Points
Female	1
CHF	1
LVEF <35%	1
Preoperative use of IABP	2
COPD	1
Insulin-requiring DM	1
Previous cardiac surgery	1
Emergency surgery	2
Valve surgery only	1
CABG + valve	2
Other cardiac surgeries	2
Preoperative Cr 1.2 to 2.1	2
Preoperative Cr 2.1	5

Table 1. ARF score after cardiac surgery, modified from the original source. Used with author's permission.

Risk score / Frequency of ARF-Dialysis

0–2 / 0.4%
3–5 / 1.8%
6–8 / 7.8%
9–13 / 21.5%

Our patient's risk is:

76 yo male with DM2 on insulin (1 point), COPD (1 point), HTN, CKD is diagnosed with severe triple-vessel CAD and is here for preop eval for CABG (2 points). Serum creatinine has been 1.4-1.6 (2 points) for the last 2 years.

1+1+2+2 = 6 points --> 7.8 % risk for developing ARF after surgery. This is higher than the usually reported frequency of postoperative ARF of less than 5%.

What are the risk factors for developing ARF after noncardiac surgery?

A study by Kheterpal et al. (Anesthesiology, 2007) listed the following 7 independent preoperative predictors for postoperatve ARF: age, emergent surgery, liver disease, body mass index, high-risk surgery, peripheral vascular occlusive disease, and chronic obstructive pulmonary disease necessitating chronic bronchodilator therapy. Several intraoperative management variables were independent predictors of ARF: total vasopressor dose administered, use of a vasopressor infusion, and diuretic administration.

The Department of Hospital Medicine and the Department of Nephrology at the Cleveland Clinic are currently conducting a study to develop a risk score for acute renal failure after noncardiac surgery (RANCS).

References

A clinical score to predict acute renal failure after cardiac surgery. Thakar CV, Arrigain S,Worley S, Yared JP, Paganini EP. Journal of the American Society of Nephrology 16(1):162-8, 2005.
Minimizing perioperative complications in patients with renal insufficiency (PDF). Martin J. Schreiber, Jr., MD, Cleveland Clinic. Cleveland Clinic Journal of Medicine, Proceedings of the Perioperative Medicine Summit, Suppl. 1 to Vol. 73, March 2006.
Acute renal failure - definition, outcome measures, animal models, fluid therapy and information technology needs: the Second International Consensus Conference of the Acute Dialysis Quality Initiative (ADQI) Group. Bellomo R, Ronco C, Kellum JA, Mehta RL, Palevsky P; Acute Dialysis Quality Initiative workgroup. Crit Care. 2004 Aug;8(4):R204-12. Epub 2004 May 24. Review.
Derivation and Validation of a Simplified Predictive Index for Renal Replacement Therapy After Cardiac Surgery. JAMA, 2007.
Predictors of Postoperative Acute Renal Failure after Noncardiac Surgery in Patients with Previously Normal Renal Function. Anesthesiology. 107(6):892-902, December 2007.
Acute Renal Failure in a General Surgical Population: Risk Profiles, Mortality, and Opportunities for Improvement. Anesthesiology:Volume 107(6)December 2007pp 869-870.

Created: 05/31/2006
Updated: 04/03/2008