Use of the Harmonic Scalpel for harvesting arterial conduits in coronary artery bypass

Abstract

A simple and effective technique is described here for harvesting the gastroepiploic artery (GEA) and radial artery (RA) using the Harmonic Scalpel. The mean time of harvesting GEA was 9 min and that of RA was 17 min. There were no injuries or spasms of those grafts and the postoperative angiograms performed in 28 patients. This shows 100% patency of the conduits. The GEA and RA are safely harvested by using the Harmonic Scalpel and the use of arterial conduits in coronary artery bypass grafting (CABG) seems to be easily achieved.

Harmonic Scalpel, Coronary artery bypass grafting, Radial artery, Gastroepiploic artery, Thermal injury

Introduction

In coronary artery bypass grafting (CABG) the gastroepiploic artery (GEA) is ordinarily harvested by ligating the fatty tissue using a silk tie or large hemostatic clips. In radial artery (RA) harvesting, multiple clips are required to manage the multiple branches of the artery for preventing radial nerve injury which is caused by thermal damage by the electrocautery. We had been harvesting the RA or GEA in this fashion. In this paper, however, we employed the technique to harvest the conduits by using the Harmonic Scalpel (Ethicon Endo-Surgery, CVG, Cincinnati, OH) and found it easy and effective for harvesting such arterial conduits.

Operative technique

Harvest of the RA (Fig. 1)

Fig. 1

In harvesting of the radial artery (RA) upward traction is provided and the branches are clipped and coagulated using the coagulating shears of the Harmonic Scalpel (H.S.). Then each branch is held using the similar technique and the entire RA between the superficial palmal artery distally and the recurrent radial artery proximally is harvested.

Simultaneous with the harvesting of the internal thoracic artery (ITA) after median sternotomy, the skin incision is made in the forearm. After opening the fascia, the lateral antebrachial cutaneous nerve is preserved on the lateral side of the incision, and a small vessel loop is passed underneath the artery. Upward traction is provided and the branches are ultrasonically coagulated using the straight hand piece Harmonic Scalpel (coagulating shears). The entire RA between the superficial palmal artery distally and the recurrent radial artery proximally is harvested.

Harvest of GEA (Fig. 2)

Fig. 2

In harvesting of the gastroepiploic artery (GEA) the omental and gastric branches including fatty tissue are cut and coagulated at 1 cm apart from the GEA using the Harmonic Scalpel (H.S.). There are three modes (flat, blunt, and shear) and five levels (from slowest, level 1 to fastest, level 5) for coagulation shears in the Harmonic Scalpel. The blunt mode at level 3 is applied to dissect the branch of the RA or GEA and the shear mode at level 5 is applied to dissect fatty tissue surrounding the arterial conduit, while bleeding may occur if there is small branch in the fatty tissue at level 5.

After harvesting the ITA a skin incision is extended 3–6 cm distally. Following to the laparotomy, the stomach, GEA, and omentum are exposed and the omental artery at the middle portion of the GEA is ligated and divided. At this point, the omental side of the GEA is proximally treated using the Harmonic Scalpel. The fatty tissue surrounding the stomach and omentum is cut and coagulated at 1 cm apart from the GEA using the Harmonic Scalpel. No clips and ties are required and the omental side of the GEA is dissected to the portion of the pyloric region. The gastric branches are then similarly dissected between the midportion of the grater curvature of the stomach and the pyloric ring.

Results

Between April and September 1997, CABG was performed in 35 patients using the ITA and GEA and/or RA. There were 30 males and five females, age ranged from 48 to 75 years. The distal number of anastomosis was two to five (mean three) per patient and besides the use of ITA in all patients, RA was used in 32, GEA in 13 and the SV in 13. The time of harvesting RA ranged from 15 to 20 min (mean, 17 min) and the incision was closed before installation of the ECC. The time for harvesting the GEA ranged from 7 to 12 min (mean, 9 min). During the harvesting the GEA two to three hemoclips were use for hemostasis of oozing from the branches which were coagulated at level five (fastest coagulation of the Harmonic Scalpel). There were no injuries or spasms of the arterial conduits during the procedures. After the harvesting RA, numbness around the thumb was noticed in one patient. However, functional symptom of the hand, hematoma, or infection was not seen. No patient required re-exploration for bleeding after the operation. During and after the operation, a calcium channel blocker was administered in all patients and a postoperative angiogram was performed in 28 patients between 7 and 18 days (mean, 12 days) after the operation. The RA or GEA graft was patent in all studied patients.

Discussion

In CABG mid-term patency of the GEA or RA has been reported and the results have encouraged the use of those arterial conduits [1],[2]. In harvesting those conduits, fat pedicle and branches of the GEA have been either tied or clipped and the multiple small branches of the RA have been clipped and cut. The Harmonic Scalpel is a disposable instrument and it causes mechanical vibration at 55 000 cycles/s and the ultrasonic coagulation is caused by denaturation of the protein. The temperature in the tissue is <80°C, while it is >300°C by the use of electrocautery. Therefore there is minimal tissue charring and thermal injury of the surrounding tissue or vessel using the Harmonic Scalpel. In the histological study regarding the depth of thermal injury it was reported that the depth, volume and lateral damage were significantly less for the ultrasonically activated scalpel (Harmonic Scalpel) compared with electrosurgery (electrocautery) [3]. The application of the Harmonic Scalpel is mostly reported in laparoscopic surgery [4] and rarely seen in the cardiac surgery. In the described technique, the GEA and RA are easily and quickly harvested by the Harmonic Scalpel and the use of arterial conduit is easily used for CABG and may be expected to improve the long term results after CABG.

Addendum

This technique of harvesting the RA and GEA and CABG was demonstrated at the Live teleconference on Complete Arterial Grafting in Melbourne, October 9, 1997.