INTRODUCTION
The advent of deep hypothermic circulatory arrest (DHCA) was a key point
for the surgical treatment of the pathologies involving the aortic arch.
The level of hypothermia ≤20°C revolutionized and made approachable,
with reasonable results, partial or total aortic arch replacement.
However, the relatively high incidence of neurologic events (NEs) argued
for the use of cerebral protection, retrograde cerebral perfusion (RCP)
or antegrade cerebral perfusion (ACP), selective (SACP) or unilateral
(UCP). Indeed, both methods were successful and the possibility to
perform more and more complex surgery increased the confidence of
surgeons, improving the clinical outcomes.
More recently, the widespread use of ACP pushed to increase the nadir
temperature to 28°C (moderately hypothermic circulatory arrest, MHCA) to
reduce some complications related to long cardiopulmonary bypass (CPB).
DHCA was perceived as a strategy not only less effective, but
potentially harmful, and MHCA+ACP became the standard of care. An
experimental study1, published in 2001, suggested that
a 20-minute cold reperfusion after DHCA before rewarming reduces the
cerebral damages due to excess of glutamate, but this finding was not
followed by clinical application. Another research, published more than
10 years after, found a reduction of NDs after 10-minute of cold
perfusion before rewarming2 after DHCA, but there were
no further studies and consequently delayed rewarming (DR) was never
included as a strategy of neuroprotection during arch surgery.
Aim of the study is to evaluate early results of aortic arch surgery and
if DHCA with 10-minute of cold reperfusion at the same nadir temperature
of the CA before rewarming (delayed rewarming, DR) can provide a
neuroprotection and a lower body protection similar to that provided by
MHCA+ACP.