How can we prevent and treat cardiogenic shock in patients who present to non-tertiary hospitals with myocardial infarction? A systematic review.

Objective: To evaluate current evidence in support of therapies for preventing and treating cardiogenic shock (CS) after acute myocardial infarction that can be initiated in hospitals without invasive cardiac facilities. Study design: Systematic review. Data sources: MEDLINE and PubMed were searched from January 1985 to May 2008 using the MeSH terms "myocardial infarction", "thrombolytic therapy", "shock, cardiogenic", "angioplasty, transluminal, percutaneous coronary", "intra-aortic balloon pumping" and "platelet aggregation inhibitors". Additional keyword and reference list searches were performed. Articles in English relating to adults were included. Study selection: Meta-analyses and comparative studies were included if they reported mortality or prevention of CS as an endpoint. In total, 35 articles were analysed (four meta-analyses, eight randomised controlled trials and 23 cohort studies). Data extraction: Studies were summarised by the first author and the level of evidence graded. Each study was checked by the second author and consensus was reached about inclusion and levels of evidence. Data synthesis: In the management and prevention of CS, the following are supported by high-level evidence: prehospital thrombolysis, transfer for emergency revascularisation (patients aged < 75 years) and thrombolysis for older patients (patients aged ≥75 years). In established CS, evidence supporting inhospital thrombolysis and intra-aortic balloon pump use in patients aged < 75 years and emergency revascularisation in older patients is limited to subgroup analyses and observational studies. Conclusions: In regional centres, prevention of CS is achieved with early fibrinolysis, preferably before hospital arrival. Patients of all ages should be considered for thrombolysis, early transfer for coronary revascularisation, and intra-aortic balloon pump insertion unless contraindicated. Glycoprotein inhibitors have no role in the management of CS in non-tertiary hospitals.