Refractory Cardiogenic Shock Treated By Veno-Arterial Ecmo; Prognostic Role Of Lactate

Refractory cardiogenic shock is characterized by severe hemodynamic instability with high mortality rate. In most critical patients extracorporeal membrane oxygenation (ECMO) is the only therapy available nowadays that gives a possibility to survive. It guarantees continuous organs perfusion with consequent normalization of serum lactates which is expression of aerobic metabolism. On these bases we investigated the use of percutaneous veno-arterial ECMO as treatment for cardiogenic shock in our Cardiac Intensive Care Unit and tried to define prognostic factors.

Results: from 1st January 2009 to 30th April 2015 we enrolled 52 patients affected by myocardial infarction (30%), acute decompensated chronic heart failure (25%), myocarditis (12%), pulmonary embolism (4%), ventricular malignant arrhythmias (29%), who developed refractory cardiogenic shock which required ECMO. 52 patients (72% male; median age 57). Duration of support: 10 ± 9 days. Outcome: 14 patients (27%) died during ECMO because of multi organ failure, sepsis and bleeding; recovery: 13 patients (25%); bridge to ventricular assist device as destination therapy: 15 patients (29%); bridge to heart transplantation: 10 patients (19%). 12/38 patients died during hospitalization after ECMO removal; 26/52 (50%) were discharged with one year overall survival of 88%. The mean peak value of serum lactate level was 3.1 mmol/L. Applying binary logistic regression model we found that lactate’s level was the most important prognostic factor; serum peak value over than 5.2 mmol/L during ECMO support predicted in ECMO mortality with an area under the curve (AUC) of 0.9236 and a p value < 0.001; combination between Sequential Organ Failure Assessment (SOFA) score and peak lactate's level during ECMO support over than 2.9 mmol/L predicted in hospital mortality with an AUC of 0.8426 and a p value of 0.003. Conclusion: in literature different scores have been proposed to predict cardiogenic shock mortality as SOFA, APACHE (Acute Physiology and Chronic Health Evaluation) and SAVE (Survival After Veno-arterial ECMO). In our experience we obtained better results in predicting outcome with seriated dosage of serum lactate in addition to these scores.