title: The effect of off-pump coronary artery bypass on mortality after acute coronary syndrome: a meta-analysis.
abstract: BACKGROUND
  Patients requiring surgical revascularisation for acute coronary syndrome (ACS) form a clinically heterogeneous group ranging from haemodynamic stability to cardiogenic shock. Whilst 'off-pump' revascularisation (OPCAB) is often considered, patient selection and operative timing remain controversial. This study aims to identify whether OPCAB may confer a mortality benefit over ONCAB in revascularisation for ACS. Secondly, we review the impact of OPCAB on completeness of revascularisation (CR) and long-term re-intervention.
  
  
  METHODS
  A systematic literature review identified 9 studies (1 randomised controlled trial) of which 8 fulfilled criteria for meta-analysis. Outcomes for a total of 3001 patients (n=817 OPCAB, 2184 'on-pump' (ONCAB)) were meta-analysed using random effects modelling. Heterogeneity, subgroup analysis and quality scoring were assessed. Primary endpoints were 30-day and mid-term mortality. Secondary endpoints were CR, revascularisation index and re-intervention.
  
  
  RESULTS
  OPCAB conferred comparable mortality to ONCAB at both 30-days and mid-term follow up (p=0.08 and p=0.46 respectively). OPCAB was also associated with less CR (WMD -0.60, 95% CI [-0.82, -0.38], p<0.00001) and a lower revascularisation index (WMD -0.25, 95% CI [-0.30, -0.19], p<0.00001), although no difference was observed in re-intervention rate (OR 1.33; 95% CI [0.99, 2.07], p=0.99).
  
  
  CONCLUSIONS
  We conclude that OPCAB may be a safe and comparable alternative to ONCAB in clinically stable ACS patients requiring urgent/emergent revascularisation. However, in order to finally determine whether OPCAB may provide any more than just comparability to ONCAB in the setting of ACS, further research must clearly define selection criteria, better characterize this heterogeneous patient group and assess the effects of incomplete revascularisation on long-term outcomes.
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London, United Kingdom.
authors.forename: Leanne
authors.initials: L
authors.lastname: Harling
authors.forename: Marco
authors.initials: M
authors.lastname: Moscarelli
authors.forename: Emaddin
authors.initials: E
authors.lastname: Kidher
authors.forename: Khalil
authors.initials: K
authors.lastname: Fattouch
authors.forename: Hutan
authors.initials: H
authors.lastname: Ashrafian
authors.forename: Thanos
authors.initials: T
authors.lastname: Athanasiou
mesh_terms: D054058:Acute Coronary Syndrome / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy*; D047549:Coronary Artery Bypass, Off-Pump / Q000401:mortality* / Q000639:trends; D006801:Humans; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic / Q000401:mortality; D013997:Time Factors; D016896:Treatment Outcome
keywords: Acute coronary syndrome; Cardiopulmonary bypass; Emergency surgery; Mortality; Off pump