From the Research
Predictors of Outcome in STEMI with Cardiogenic Shock
- Serum lactate and mixed venous oxygen saturation are both used as markers of tissue oxygenation in shock states, but their relationship and predictive value for outcome in STEMI with cardiogenic shock are not well established 1.
- A study found that serum lactate levels at all time points and lactate clearance after 6 hours were associated with mortality in cardiogenic shock treated with temporary mechanical circulatory support, suggesting that serum lactate is an important prognostic biomarker in this context 2.
- Another study found that lactate and mixed venous oxygen saturation correlated poorly, and that lactate can predict mixed venous oxygen saturation only when patients are at or below the critical oxygen delivery threshold, which is not often met in shock patients 1.
- A review of optimal perfusion targets in cardiogenic shock highlighted the utility of serum lactate metabolism and venous oxygen saturation as prognostic markers and guides for therapy, but did not establish a clear relationship between the two 3.
- A study of STEMI patients with cardiogenic shock treated with IMPELLA found that lactate levels on admission were associated with in-hospital mortality, and that a lactate cut-off value of 6.9 mmol/L showed the best discrimination for in-hospital mortality 4.
- A comparison of central and mixed venous oxygen saturation in circulatory failure found that central venous oxygen saturation overestimated mixed venous oxygen saturation, and that the two measurements are not interchangeable numerically 5.
Comparison of Serum Lactate and Mixed Venous Oxygen Saturation
- The available evidence suggests that serum lactate and mixed venous oxygen saturation are not interchangeable markers of tissue oxygenation, and that serum lactate may be a more reliable predictor of outcome in STEMI with cardiogenic shock 2, 1, 4.
- However, mixed venous oxygen saturation may still have a role in guiding therapy and predicting outcome in certain clinical contexts, such as when lactate levels are not available or are elevated due to non-hypoxic causes 3, 5.
- Further research is needed to fully establish the relationship between serum lactate and mixed venous oxygen saturation, and to determine the optimal perfusion targets for STEMI patients with cardiogenic shock 3, 4.