Veno-Arterial Extracorporeal Membrane Oxygenation for Cardiogenic Shock : An Introduction for the Busy Clinician

Cardiogenic shock is a high-acuity, potentially complex, and hemodynamically diverse state of end-organ hypoperfusion that is frequently associated with multisystem organ failure. Despite improving survival in recent years, patient morbidity and mortality remain high, and there are few evidence-based therapeutic interventions known to clearly improve patient outcomes. This scientific statement on cardiogenic shock summarizes the epidemiology, pathophysiology, causes, and outcomes of cardiogenic shock; reviews contemporary best medical, surgical, mechanical circulatory support, and palliative care practices; advocates for the development of regionalized systems of care; and outlines future research priorities.

The objective of the EuroHeart Failure Survey II (EHFS II) was to assess patient characteristics, aetiology, treatment, and outcome of acute heart failure (AHF) in Europe in relation to the guidelines on the diagnosis and treatment of AHF published by the European Society of Cardiology. Patients hospitalized for AHF were recruited by 133 centres in 30 European countries. Three thousand five hundred and eighty patients were entered into the database by the end of August 2005. Mean age was 70 years, and 61% of patients were male. New-onset AHF (de novo AHF) was diagnosed in 37%, of which 42% was due to acute coronary syndromes (ACS). Clinical classification according to the guidelines divided AHF patients into (i) decompensated HF (65%), (ii) pulmonary oedema (16%), (iii) HF and hypertension (11%), (iv) cardiogenic shock (4%), and (v) right HF (3%). Coronary heart disease, hypertension, and atrial fibrillation were the most common underlying conditions. Arrhythmias, valvular dysfunction, and ACS were each present as precipitating factor in one-third of cases. Preserved left ventricular ejection fraction (> or =45%) was observed in 34%. Valvular disorders were common, especially mitral regurgitation (MR) which was reported on echocardiography in 80% of patients. Median length of stay was 9 days, and in-hospital mortality 6.7%. At discharge, 80% of patients were on angiotensin-converting enzyme-inhibitors or angiotensin receptor blockers, whereas 61% were taking beta-blocker medication. Decompensated HF is the most common clinical presentation of AHF patients. More than one-third of AHF patients do not have a previous history of HF, and new-onset HF is often caused by ACS. Preserved systolic function is found in a substantial proportion of the patients. The prevalence of valvular dysfunction is strikingly high and contributes to the clinical presentation. The EHFS II on AHF verified that the use of evidence-based HF medication was well adopted to clinical practice.

Extracorporeal life-support as an adjunct to cardiac resuscitation has shown encouraging outcomes in patients with cardiac arrest. However, there is little evidence about the benefit of the procedure compared with conventional cardiopulmonary resuscitation (CPR), especially when continued for more than 10 min. We aimed to assess whether extracorporeal CPR was better than conventional CPR for patients with in-hospital cardiac arrest of cardiac origin. We did a 3-year prospective observational study on the use of extracorporeal life-support for patients aged 18-75 years with witnessed in-hospital cardiac arrest of cardiac origin undergoing CPR of more than 10 min compared with patients receiving conventional CPR. A matching process based on propensity-score was done to equalise potential prognostic factors in both groups, and to formulate a balanced 1:1 matched cohort study. The primary endpoint was survival to hospital discharge, and analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00173615. Of the 975 patients with in-hospital cardiac arrest events who underwent CPR for longer than 10 min, 113 were enrolled in the conventional CPR group and 59 were enrolled in the extracorporeal CPR group. Unmatched patients who underwent extracorporeal CPR had a higher survival rate to discharge (log-rank p<0.0001) and a better 1-year survival than those who received conventional CPR (log rank p=0.007). Between the propensity-score matched groups, there was still a significant difference in survival to discharge (hazard ratio [HR] 0.51, 95% CI 0.35-0.74, p<0.0001), 30-day survival (HR 0.47, 95% CI 0.28-0.77, p=0.003), and 1-year survival (HR 0.53, 95% CI 0.33-0.83, p=0.006) favouring extracorporeal CPR over conventional CPR. Extracorporeal CPR had a short-term and long-term survival benefit over conventional CPR in patients with in-hospital cardiac arrest of cardiac origin.