Study designs of evaluations included in the review
Randomised controlled trials (RCTs) and observational studies were eligible for inclusion. The designs of the observational studies included in the review were unclear. The included observational studies compared outcomes for those admitted to hospitals with or without catheterisation facilities, and those carried out in different geographical regions. The follow-up periods ranged from 3 months to 3 years in the RCTs, and from 30 days to 2 years in the observational studies.
Specific interventions included in the review
Studies that compared a routine invasive management with noninvasive management were eligible for inclusion. Protocols used in the included studies were broadly similar: invasive management involved routine cardiac catheterisation, followed by revascularisation with percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery; noninvasive management involved risk stratification according to symptoms, with catheterisation and revascularisation only for those with reversible ischaemia. Studies differed in the delay between onset of AMI and the use of routine catheterisation in the invasive groups: from 0.1 hours to 48 hours after thrombolysis or 72 hours after admission. In some studies, people in the noninvasive arm had routine cardiac catheterisation before leaving hospital.
Studies that compared admissions to hospitals with and without availability of cardiac catheterisation, or in different geographical locations, were also sought. In these studies between 47 and 85% of the invasive group underwent catheterisation, compared with between 3 and 52% of the noninvasive group.
Participants included in the review
Studies on people with uncomplicated ST-elevation AMI were sought. People with previous infarction or cardiogenic shock were excluded from some of the studies, whilst they were included in others. The authors stated that the participants in the included studies were relatively young and had a low risk of recurrent cardiac events.
Outcomes assessed in the review
The primary outcomes of interest were the incidence of mortality or reinfarction. The incidence of revascularisation (PCI and CABG) were also reported.
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.