- Check each risk factor that applies to the patient. Each item is worth 1 or 2 points as labeled.
- For Surgery Type and Preoperative Creatinine, select the appropriate value from the dropdown menus.
- The total score updates automatically. The result shows the score, risk category, and estimated probability of AKI requiring dialysis.
- Use as a preoperative counseling and risk-mitigation tool — not as a decision to withhold surgery.
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When to Use
Use the Thakar score preoperatively in adults scheduled for cardiac surgery to estimate the risk of postoperative acute renal failure (ARF) requiring dialysis. The model was derived and validated in a large Cleveland Clinic cohort and includes eleven readily available clinical predictors.
Appropriate population
Adults undergoing cardiac surgery (CABG, valve surgery, combined CABG + valve, or other cardiac surgical procedures) with available preoperative clinical data. Particularly useful for preoperative nephrology consultation, shared decision-making, and perioperative risk mitigation planning.
When NOT to rely on it
The score was developed for elective and urgent cardiac surgery; applicability to emergent thoracic aortic surgery or transcatheter procedures is uncertain. It predicts dialysis-requiring ARF, not milder AKI stages. Do not use this score alone to refuse or delay surgery — integrate findings with the full clinical picture and a multidisciplinary cardiac team.
Pearls & Pitfalls
Preoperative risk mitigation
A high or very high Thakar score should prompt nephrology consultation before surgery, optimization of preoperative creatinine if time allows (e.g., treating heart failure, holding nephrotoxins), explicit patient counseling about dialysis risk, and heightened perioperative monitoring (early hemodynamic optimization, avoidance of hypotension, minimizing contrast, careful fluid balance).
Key drivers of risk
Preoperative creatinine ≥2.1 mg/dL (5 points) and emergency surgery (2 points) carry the heaviest individual weights. Combined CABG + valve or other cardiac surgery also adds 2 points versus isolated CABG. IABP placement (2 points) usually reflects severely reduced cardiac output or unstable hemodynamics — itself a major AKI driver. Multiple moderate-weight factors compound rapidly: a diabetic woman in CHF with a creatinine of 1.5 mg/dL can easily reach score 6 (High risk) before even considering surgery type.
Pitfalls
(1) The score predicts dialysis-requiring ARF — it does not capture all postoperative AKI stages. (2) KDIGO AKI staging should still guide postoperative monitoring regardless of score. (3) "Female sex" in this model is a biological risk variable reflecting hormonal and physiologic differences in renal reserve — it does not reflect gender identity. (4) The score was derived in a single-center North American cohort; local calibration may differ. Always confirm with current literature and institutional protocols.
Why Use It
Cardiac surgery-associated AKI requiring dialysis carries in-hospital mortality exceeding 50–60% and dramatically increases ICU length of stay, resource utilization, and the risk of CKD progression in survivors. Identifying high-risk patients before the operating room creates an actionable window for nephrology-cardiac co-management, targeted hemodynamic preparation, and explicit shared-decision conversations about dialysis risk and recovery trajectory. The Thakar score remains the most widely validated preoperative AKI prediction model for cardiac surgery, referenced in major nephrology and cardiac surgery guidelines.
Thakar Score — AKI Requiring Dialysis After Cardiac Surgery
Check all risk factors present and select surgery type and preoperative creatinine. The score and risk category update automatically.
Patient Risk Factors (checkboxes)
⚕ Thakar CV et al. J Am Soc Nephrol. 2005;16(1):162–168. Risk estimates are from the original derivation cohort; local rates may differ. Score ranges 0–13. This tool is for licensed clinicians and does not replace individualized surgical risk assessment.
Next Steps
Use the result to guide preoperative risk communication and nephrology co-management.
- For Low risk (0–2): standard perioperative renal monitoring; document baseline creatinine; ensure adequate hydration on the day of surgery.
- For Moderate risk (3–5): consider nephrology input; optimize modifiable factors (heart failure, hyperglycemia); hold nephrotoxins; explicit informed-consent discussion.
- For High or Very High risk (≥6): nephrology consultation recommended; shared decision-making about dialysis risk; preoperative optimization of creatinine if feasible; postoperative ICU monitoring plan; early furosemide or CRRT threshold discussion.
- Apply KDIGO AKI staging criteria postoperatively regardless of preoperative score.
- Document the score and risk discussion in the surgical consent note.
Evidence & References
Scoring Model
| Risk Factor | Points |
|---|---|
| Female sex | 1 |
| Congestive heart failure | 1 |
| LVEF < 35% | 1 |
| Preoperative IABP | 2 |
| COPD | 1 |
| Insulin-requiring diabetes | 1 |
| Previous cardiac surgery (reoperation) | 1 |
| Emergency surgery | 2 |
| Surgery type: CABG only | 0 |
| Surgery type: Valve only | 1 |
| Surgery type: CABG + valve or Other | 2 |
| Preop creatinine < 1.2 mg/dL | 0 |
| Preop creatinine 1.2 to < 2.1 mg/dL | 2 |
| Preop creatinine ≥ 2.1 mg/dL | 5 |
Published Risk Bands
| Score | Category | Estimated ARF Risk (dialysis) |
|---|---|---|
| 0–2 | Low | ~0.5% |
| 3–5 | Moderate | ~1.8% |
| 6–8 | High | ~7.8% |
| 9–13 | Very High | ~21.5% |
References
- 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(1):162–168.
- Kidney Disease: Improving Global Outcomes (KDIGO) AKI Work Group. KDIGO Clinical Practice Guideline for Acute Kidney Injury. Kidney Int Suppl. 2012;2(1):1–138.
- Hobson CE, Yavas S, Segal MS, et al. Acute kidney injury is associated with increased long-term mortality after cardiothoracic surgery. Circulation. 2009;119(18):2444–2453.
