INTRODUCTION
Different hypothermia regimens alone or combined with selective cerebral
perfusion can be used for cerebral protection during surgical
interventions involving the aortic arch. Historically, cooling of the
brain to profoundly hypothermic levels seemed safe. However, transitions
to warmer hypothermic temperatures in conjunction with antegrade
cerebral perfusion has become the trend in the last decades1-3. Despite favorable clinical results reported with
newer techniques, a variation in hypothermia regimes persists to exist
between centers worldwide.
Evidence on outcome differences between the proposed techniques and
different levels of hypothermia during aortic arch surgery is scattered
across many publications. Over the last decades, several meta-analyses
have compared different levels of hypothermia in different combinations
in a pairwise fashion 4-7. However, no meta-analysis
has compared all 3 levels of hypothermia, deep, moderate and mild.
Network meta-analysis (NMA) allows comparisons between more than 2
treatment arms. The advantage of network meta-analysis is that it
facilitates indirect comparisons of multiple interventions that have not
been studied in a head-to-head fashion 8. Hence we
have used a network meta-analysis approach to compare the effect of deep
hypothermic circulatory arrest (DHCA), moderate hypothermic circulatory
arrest (MHCA) and mild hypothermic circulatory arrest (mild HCA) on the
operative mortality, postoperative occurrence of stroke and acute kidney
renal failure (AKI) after aortic arch surgery.