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Pragliola et al. Vessel Plus 2019;3:22 I http://dx.doi.org/10.20517/2574-1209.2019.003 Page 5 of 9

temperature, at 10 °C the oxygen requirements should be in the 15% to 20% range of the baseline. Hence ice
slush for local temperature control is added by the surgeon in the pericardium at the aortic cross clamp time.
However, continuous myocardial temperature is not routinely used.

The cardioplegia can also be infused directly into the coronary arteries in case of severe Aortic regurgitation,
as can be infused retrogradely at the some doses used in the aortic root although this is not common practice
according to the literature. Unlikely other blood cardioplegias, we strongly advise not to use a continuous
infusion. This can result either in an excess of volume or Lidocaine and magnesium. Najjar et al. in a series
[12]
of 14 patients undergoing re-operative surgery and continuous infusion reported a mean total volume of
4367 mL ± 751 mL for an aortic cross clamp time of 81 min ± 35 min. With retrograde continuous infusion
in patients submitted to aortic valve reimplantation, Jiang et al. reported a 26% incidence of postoperative
[13]
heart block resulting in 6.7% incidence of permanent heart block. Due to the limited number of patients and
the inherent surgery they were submitted to, it is not possible to reach a definite conclusion, but caution is
advised.

EXPERIMENTAL STUDIES
The conflicting evidences on the premature myocardium metabolism which were evident at the time the
DNC was developed at Boston Children Hospital have been stressed by Matte in his report. In brief the Del
+
+
Nido was conceived as a hyperpolarizing (K ), extracellular (Na ) glucose free (Plasmalyte), hyperosmolar
(Mannitol), buffered (Bicarbonate, blood proteins) solution controlling the calcium influx into the cells
(Magnesium and Lidocaine). The presence of lidocaine in an unperfused coronary bed (slowly wiped off
by the collateral coronary flow) allows for long intervals between the infusion of the solution. This is as
important as the maintenance of a low myocardial temperature and the use of the cold cardioplegic solution
when manually testing the anastomosis during CABG surgery. These details are collateral, but not less
important parts of the technique in adults .
[14]

However, there are at least two experimental studies supporting the use of the DNC in aged hearts. During
cardioplegic arrest induced by DNC in an isolated cells model from senescent rats, the intracellular Calcium
content was lower and the cells were not reactive to electric filed stimulation as well as they did not develop
hypercontraction at reperfusion contrary to the same model treated with conventional cardioplegias. The
Authors concluded that according to these results, the DNC had the potential to better protect senescent hearts
preventing electromechanical activity during the arrest and hypercontraction at the time of reperfusion .
[15]
Similarly, in an isolated working model of senescent hearts, the treatment group that underwent 60 min of
cardiac arrest induced by DNC had better contractility and lower enzyme release compared to the group
treated with conventional cardioplegia .
[16]

EXPERIENCES IN ADULT PATIENTS
Interestingly, although it is now clear that major cardiothoracic units are regularly using the DNC solution,
available studies deal only with limited subpopulations.

Matte et al. , describing the development of the DNC reports the regular use in Adult Congenital cases
[10]
at Boston Children Hospital. Ota et al. and Sorabella et al. published their experiences with first time
[18]
[17]
and re-operative Aortic Valve surgery, all with safe and comparable results. Mongero state that the DN
[19]
cardioplegia is the only solution in use in their Centre, the Columbia University Presbiterian Hospital NY,
since 2011 and call for a broader use of it in adults. O’Donnell et al. reports that the DNC is the cardioplegia
[20]
of choice in CABG since 2015.