Preparation of Internal Thoracic Artery Clinical Trial
Official title:
Skeletonized Internal Thoracic Artery Harvesting: A Low Thermal Electrosurgical Device Provides Improved Endothelial Layer and Better Integrity of the Vessel Wall
Electrosurgery is fundamental to the precise, fast and bloodless preparation of internal thoracic artery grafts in cardiac surgery. The PEAK PlasmaBlade is a monopolar electrosurgical device that uses pulsed radiofrequency energy to generate a plasma-mediated discharge along an insulated electrode, creating a cutting edge while the blade stays near body temperature. The aim of this study is to compare the histological samples, cardiac computed-tomography of graft patency, and clinical outcomes of patients after off-pump coronary artery bypass grafting with preparation of the internal thoracic arteries by a conventional electrosurgical device and the PlasmaBlade.
Electrosurgery is fundamental to the precise, fast and bloodless preparation of internal
thoracic artery grafts in cardiac surgery. The fundamental performance of electrosurgical
dissection is created by using a continuous radiofrequency energy waveform, which thermally
ablates soft tissue, leaving a collateral damage zone of 100-400 µm. The basic mechanism of
tissue ablation and dissection in electrosurgery involves Joule heating of the conductive
tissue by electric current, that leads to vaporization and ionization of the water content in
the tissue adjacent to the electrode, and ultimately to vapor expansion and tissue
fragmentation. Tissue heated below the vaporization threshold remains in place, but can
undergo thermal denaturation determined by the temperature levels and duration of the
hyperthermia. Thus, to confine the collateral damage zone in tissue, both of these factors
should be minimized.
In contrast to continuous radiofrequency energy, pulsed electric waveforms with burst
durations ranging from 10 to 100 µsec applied via an insulated planar electrode with 12 µm
wide exposed edge produces a plasma-mediated, precise dissection of tissues with a lower
collateral damage zone ranging from 2 to 10 µm. The greatly reduced zone of thermal damage,
compared to conventional electrosurgical devices, may provide faster healing and less
scarring.
The PEAK PlasmaBlade (Medtronic Advanced Energy, Portsmouth, NH USA) (FDA 510(k), CE-No.
540861, Model Number PS200-040) is an electrosurgical device that uses pulsed radiofrequency
energy to generate a plasma-mediated discharge along the exposed rim of an insulated blade,
creating an effective, precise cutting edge while the blade stays near body temperature.
Plasma is an electrically conductive cloud created when the energy contacts tissue. This
conductive cloud or "plasma" allows the radiofrequency energy to cross at much lower overall
power levels. This use of less energy via plasma results in lower operating temperatures and
less thermal damage. This technology has been shown to effectively dissect ophthalmologic and
cutaneous tissues as precisely as a scalpel with the hemostatic control of conventional
electrosurgery in clinical and experimental settings.
Concentrating on bypass grafts, the thoracic internal arteries (ITAs) demonstrate our most
valuable conduit for revascularization of the coronary arteries. Compared to pedicled
arteries, skeletonized ITAs have demonstrated a tendency to better long term patency.
Additionally, skeletonized conduits are useful in expanding the number of anastomoses per
patient and reducing the incidence of sternal complications.
The use of a dissection device that provides precise preparation, including optimal bleeding
control without overly damaging the surrounding tissue, might be an optimizing factor for the
protection of these valuable bypass grafts. The aim of this study was to compare the
histological assessment, cardiac computed-tomography and clinical outcomes of patients
following off-pump coronary artery bypass grafting with preparation of the ITAs by
conventional electrosurgery and the PlasmaBlade.
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