title: The effect of ventricular assist devices on long-term post-transplant outcomes: a systematic review of observational studies.
abstract: OBJECTIVE
  Ventricular assist device (VAD) therapy is widely used as a bridge to cardiac transplant. Studies addressing the effect of VADs on post-transplant outcomes have shown conflicting results. It is imperative to review this evidence to inform clinical decision making and future research. Our aim was to systematically evaluate the effect of VAD therapy on long-term post-transplant outcomes in heart transplant recipients.
  
  
  RESULTS
  We searched online databases (Medline, PubMed, Embase, and CINAHL) and references of included articles. Comparative studies evaluating the effect of VADs on post-transplant outcomes in adults were included and study results were meta-analysed using random-effects models. We conducted subgroup analyses to assess the effect estimate of extra- vs. intra-corporeal VADs and to evaluate the impact of transplant era and listing status. Overall, we identified 31 observational studies. One-year post-transplant mortality in recipients bridged with an extra-corporeal VAD was significantly higher than in non-bridged recipients (RR 1.8, 95% CI 1.53-2.13, I(2)= 1%), while patients supported with an intra-corporeal VAD had similar mortality to non-bridged recipients (RR 1.08, 95% CI 0.95-1.22, I(2)= 0%). The risks of rejection within the first post-transplant year and coronary allograft vasculopathy were not significantly different between patients with or without VAD support prior to transplant. Publication bias was low; however, the risk of bias across studies was moderate to high.
  
  
  CONCLUSIONS
  Intra-corporeal VAD support does not have a deleterious impact on post-transplant outcomes. However, post-transplant survival may be poorer in the subgroup of patients supported with extra-corporeal devices. Studies with greater methodological rigour are warranted.
authors.affiliation: Division of Cardiology and Heart Transplantation, Toronto General Hospital, 585 University Avenue, Toronto, Ontario, Canada. carolina.alba@uhn.on.ca
authors.forename: Ana C
authors.initials: AC
authors.lastname: Alba
authors.forename: Michael
authors.initials: M
authors.lastname: McDonald
authors.forename: Vivek
authors.initials: V
authors.lastname: Rao
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Ross
authors.forename: Diego H
authors.initials: DH
authors.lastname: Delgado
mesh_terms: D016001:Confidence Intervals; D006333:Heart Failure / Q000453:epidemiology / Q000401:mortality / Q000601:surgery*; D016027:Heart Transplantation / Q000009:adverse effects / Q000706:statistics & numerical data*; D006353:Heart-Assist Devices / Q000009:adverse effects / Q000706:statistics & numerical data*; D006801:Humans; D012306:Risk; D018570:Risk Assessment; D013997:Time Factors; D014180:Transplantation; D016896:Treatment Outcome; D014481:United States