Since CABG was first brought into daily practice,
several attempts have been made to develop an ideal
graft. However, the superiority of the arterial grafts into
the venous grafts was proven: the ITA was introduced in 1960s, and since then, it has been the optimal conduit of
choice.[
2,
4,
6,
14-
16] The ITA has higher long-term patency
rates, compared to other grafts.[
13-
15] While the typical
atherosclerotic changes and intimal hyperplasia can
develop faster in the venous grafts, they are seen much
rarely and later with the ITA grafts.[
17-
21]
Currently, one of the most commonly used
techniques in the ITA harvesting is pedicled preparation
of the conduit with the surrounding soft tissue, satellite
veins, and endothoracic fascia.[2-4,14] This method
facilitates harvesting and reduces the possibility
of vascular injury.[4] In addition, sustainability of
venous and lymphatic drainage ensures the protection
of vasa vasorum and continued activity of the
conduit.[4,5] Since the very first cases for CABG, it has
been prepared using electrocautery.[22] The main goal
of using electrosurgery is to ensure a clean and clear
incision and coagulation with minimum collateral
heat injury.[23,24] The PlasmaBlade™ tissue dissection
devices are introduced as novel surgical devices with
pulsed-plasma technology to avoid adverse effects of
conventional electrocautery.[23,24] It has been developed
to induce minimal thermal damage during the tissue
dissection and coagulation and the device is called as
PEAK® Surgery System together with PULSAR®
Generator.[23-25] Most electrosurgical cutting tools use continuous radio-frequency (RF) waveforms which
thermally vaporize the soft tissue through heating
and via an electric arc.[23-25] This results in cutting
and coagulation which leaves a wide zone of collateral
thermal tissue damage. As the PlasmaBlade™ device
receives RF energy in short pulses via a highly
insulated cutting electrode, it has an ability to cut at
a much lower mean temperature than conventional
electrosurgery.[4]
Furthermore, the basic operating principle of this
system is that it creates a vapor cloud with the device
end contacting with the tissue. The ionization of the
water molecules in the vapor cloud creates a specific
environment for the dissection. It has been shown that
the dissection is performed at a lower temperature
(approximately 45 ˚C) with a lower power, a lower
voltage, and a lower current due to the ionization of
the water molecules.[23,24] The mean temperature for
the conventional cautery is 250 to 350 ˚C.[23,24] Unlike
conventional electrocautery systems, this device does not provide a fixed voltage. Its pulsed-voltage values
ranging between +300 and -100 within nanoseconds
ensure maximum ionization of the water molecules.
As the device end is covered with a glass-based silicon
agent, the active region becomes narrow and only
the crescent-shaped region which is approximately
0.5 mm thick at the tip is active.[7-11] As the impedance
of the tissue decreases within this specifically created
environment, less tissue necrosis and thermal damage
occur and such a dissection is obtained closer to that
performed with a scalpel.[23-25]
A variety of preclinical and clinical studies were
carried out in different surgical zones while and
after developing the peak surgery system.[23] The
studies were initially started with in vivo and ex vivo
preclinical testing on animals and, then, clinical
studies were performed.[23] It has been shown through
these studies that such a dissection which has a scalpel
precision and causes hardly any thermal damages at
lower power levels can be performed using the PEAK
surgery system and that the system has a hemostasis
capability equal to the conventional electrocautery at
higher power levels.[23]
No matter how much lower the power is kept in
conventional electrocautery during ITA harvesting,
the resulting collateral heat may cause damage to
both the surrounding tissue and the ITA itself. The
traction induced by the perivascular hematoma and
electrocautery burn creates a local turbulent flow
in the artery. Such turbulent flow may accelerate
atherosclerosis due to the endothelial damage as
previously reported in the literature and pose an
adverse effect on the graft patency.[5] In our study,
severe bleeding areas in the perivascular tissue were
found significantly higher in the electrocautery group. Therefore, we believe that less perivascular bleeding in
the pedicle with the PlasmaBlade™ system may reduce
the turbulent flow and increase the patency rates.
It has been shown that an intact elastic
lamina following the ITA harvesting may prevent
atherosclerosis. In our study, the width of the injury
zone was found to be significantly lower in the
patients treated with the PlasmaBlade™ rather than
electrocautery. Thus, it suggests that the PlasmaBlade™
may reduce collateral thermal injuries, and accordingly,
increase the graft patency rates.
In another study, Lehtola et al.[26] demonstrated that
an endothelial injury and mural thrombosis developed,
when the tip of the electrocautery contacted with the
ITA wall or the hemostatic metallic clips, which might
be a reason for early and late graft failures. In this study,
histopathological examination of the electrocautery
group revealed thermal damage-induced extensive
cautery artefacts in the arterioles of the ITA.
Several preclinical studies have shown that the
PlasmaBlade™ requires less than half of the energy
produced in the conventional electrocautery devices
to achieve similar dissection and coagulation results
due to the advance level insulation of its electrode
configuration, and its pulsed electric wave forms.[23]
This ensures that the temperature during the procedure
is less than half of the temperature of the conventional
devices, thereby, providing a decrease in the heat
transfer by more than a half and a decrease by 50 to 90%
in the depth of the thermal injury of the surrounding
tissues.[23] Similarly, in our study, the width of the
injury zone and severe perivascular bleeding were
significantly lower in the PlasmaBlade™ group than
the conventional electrocautery group.
Moreover, postoperative sensorial abnormalities
on the thoracic wall (i.e. hypoesthesia, hyperalgesia,
and allodynia) are associated with the utilization
of electrocautery, which may adversely affect the
wound healing.[27] It is well-known that the surgical
smoke impairs the image quality and the cautery
smoke increases the risk of cancer.[28] In addition, the
requirement for the cautery tip to be frequently cleaned
may be challenging; however, more importantly,
burn injuries have been reported in case of improper
grounding.[28] In the literature, the advantages of the
PlasmaBlade™ have been published.[23] Nonetheless,
the ability of the PlasmaBlade™ to provide
surgical hemostasis and its effects on postoperative
bleeding and blood product utilization should be
further evaluated in clinical studies. The major
concern of bilateral ITA harvesting is the sternal
wound infections, particularly in diabetic patients.
Therefore, it should also be investigated whether the
Plasmablade™ would make a difference in wound
infections.
In conclusion, our study results suggest that the
PlasmaBlade™ is safer and more effective in preserving
the integrity of the intima and pedicle of the internal
thoracic artery than electrocautery for internal thoracic
artery harvesting in coronary artery bypass grafting. No
matter how much easier electrocautery makes internal
thoracic artery harvesting, therefore, novel technologies
such as PlasmaBlade™ are needed to be developed to
minimize side effects. A well-preserved endothelial
function may provide higher graft patency rates.
Declaration of conflicting interests
The authors declared no conflicts of interest with
respect to the authorship and/or publication of this
article.
Funding
The authors received no financial support for the
research and/or authorship of this article.