Endoscopic vessel harvesting in coronary artery bypass graft surgery

Since its inception in 1997, EVH has considerably reduced the morbidity associated with vessel conduit harvesting and has virtually eliminated patients’ postoperative leg pain.

Christopher W. Nickum, MPAS, PA-C

The author is the Chief PA in the Section of Cardiothoracic Surgery, Cleveland Clinic Florida, Weston, Fla. He has a consulting agreement with Ethicon/Johnson & Johnson, who manufacture the CLEARGLIDE Endoscopic Vessel Harvesting System.

   If you prefer to view this article in PDF form, click here.

Here and on the cover: Christy Krames

For an explanation of competencies, click here.

According to the Society of Thoracic Surgeons’ National Database, Spring 2005 Executive Summary Report, 160,185 coronary artery bypass graft (CABG) procedures were performed in the United States in 2004.¹ The various techniques employed to harvest conduits used to perform these procedures range from the conventional open approach employing a single linear incision to the robotically assisted endoscopic technique resulting in three pencil-size puncture sites in the chest. The morbidity associated with the conventional open technique and patient complaints of considerable postoperative pain have served as a catalyst for the development of less invasive means of vessel harvesting.

After briefly reviewing the conventional approach to vessel harvesting as well as some of the less invasive techniques, this article discusses endoscopic vessel harvesting (EVH), ending with the most recent and technologically challenging of EVH techniques, robotic-assisted endoscopic internal thoracic artery (ITA) harvesting. The objective is to inform primary care providers of the progression, development, and benefits of EVH, thereby inspiring them to request its use for their patients who are referred for myocardial revascularization.  

Vessel harvesting techniques

Conventional open technique In May 1967 at the Cleveland Clinic, Favoloro and Effler utilized the greater saphenous vein obtained by open saphenectomy to perform the first CABG procedure on a 51-year-old woman.² Subsequently, the open technique became the gold standard for procurement of the saphenous vein for CABG. Typically, this approach involves a single linear incision through the subcutaneous tissue, starting at the ankle and extending to the groin. The vein is then dissected with Metzenbaum scissors, and vein tributaries are ligated and secured with either vascular clips or suture ties. Closure is characteristically performed in multiple layers of running Vicryl sutures with either skin staples or a running subcuticular stitch for skin closure.

The morbidity associated with this technique has ranged from 1.5% to 24%, and problems can vary from superficial cellulitis that responds to oral antibiotics and local wound care to deep tissue infections or osteomyelitis necessitating extensive wound care, debridement, and even, in rare instances, limb amputation (see Figure 1).^3-7 From 1967 to the late 1970s, the morbidity associated with conventional vessel harvesting, although not insignificant, was considered to be an acceptable risk of CABG.

Bridging technique One of the earliest and most common methods employed to help circumvent morbidities associated with open saphenectomies, the basic bridging technique (BT) involves creation of four to six 4-cm incisions, starting at the ankle, with subcutaneous tunnels created at 7- to 8-cm intervals (see Figure 2).⁸ Using direct visualization via Army-Navy retractors, the operator uses standard instrumentation to perform vein dissection and branch ligations beneath the skin bridges until the vein is completely free and can be easily removed from the leg.

While bridging has reduced the wound morbidity associated with saphenectomy for CABG,⁸ concerns have been raised about whether this technique causes undue trauma to the vein through excessive manipulation that results in endothelial and intimal disruption.^9,10 Multiple studies have been performed in which vein segments obtained through bridging or minimally invasive harvesting were subjected to light and electron micros-copy to evaluate endothelial integrity.^8,11 To date, how-ever, no prospective, randomized study has been performed to assess long-term or even mid-term vein patency obtained through the BT. This lack of evidence, combined with concerns about vessel stretching, led to the development and utilization of instruments equipped with light sources for better visualization, resulting in less manipulation and presumably less vessel trauma.

Minimally invasive greater saphenous vein harvesting In this review, minimally invasive vein harvesting (MIVH) and the BT are differentiated based on the lighted laryngoscope-type instruments utilized during MIVH, which are typically absent in the BT. In 1997, Tevaearai and colleagues first described an MIVH technique using the MiniHarvest System (US Surgical Corporation, Norwalk, Conn) in 30 patients.¹² This system employed a laryngoscope-type blade coupled with a light source and was used to visualize the vein beneath the skin bridges to facilitate vein dissection and tributary control. Tevaearai reported a significant reduction in postoperative pain (0%) and a high incidence of healing (100%) with MIVH compared to the conventional method of saphenectomy, previously reported at 27% and 73%, respectively. Despite these benefits, he described a 27% incidence of hematoma formation in the MIVH group, which was significantly higher than that in subsequent reports on MIVH techniques.^13,14    

Although MIVH techniques were performed successfully and demonstrated a clear superiority to conventional techniques, they were still considered a significant cause of morbidity for the cardiac surgical patient. The benefits of laparoscopic general surgery were soon apparent to cardiac surgeons, who sought the same benefits for their patients. By the mid 1990s, technology used in laparoscopic general surgery was translated and applied to vessel harvesting for CABG in the form of EVH.

Endoscopic greater saphenous vein harvesting In 1997, Allen and Shaar first described endoscopic saphenous vein harvesting (ESVH) in 30 patients.¹⁵ The instrumentation consisted of a 5-mm endoscope with a 30-degree angled lens, endoscopic vessel dissector, modified vein stripper, and standard endoscopic equipment including a television monitor, light source, fiberoptic camera, and CO₂ insufflator. The endoscope was inserted and advanced over the anterior portion of the vein in a cephalad direction. With continuous CO₂ insufflative assistance, a space was created in the subcutaneous tissue within which the dissection was carried out. Branches were clipped with vascular clips and cut with endoscopic scissors. Once the vein was freed, the proximal portion was first ligated with a large clip and then cut with endoscopic scissors. Two to four transverse incisions measuring 2.5 cm each were employed for the procedure.

Over the ensuing years, the technique and instrumentation were modified with the addition of a cone- shaped optical dissector and replacement of clips and scissors with bipolar cauterization for vein tributary control. Today, the two most widely utilized systems in cardiac surgery are CardioVations’ CLEARGLIDE System (CardioVations, Somerville, NJ), which is the current generation of Allen’s “endodissector,” and Guidant’s VasoView Uniport Plus System (Guidant Corporation, Santa Clara, Calif). Both systems allow the user the potential to safely and effectively remove the saphenous vein from the leg through as little as one 2.5-cm incision (see Figure 3).

Along with the introduction of ESVH came concerns about its potential for vein trauma with resulting intimal disruption, ischemic stricture, and reduced graft patency. In response, histologic, light, and electron micros-copy examinations were performed comparing vein segments obtained endoscopically to vein segments ob-tained by open saphenectomy. The results demonstrated no significant disruption of the vein intima with enscopic harvest compared with open saphenectomy.^11,16,17 These conclusions were key to the ongoing development and adoption of ESVH since determina-tion of vein intimal trauma would likely have resulted in abandonment of the technique.

Additional concerns with ESVH were the increased expense of instrumentation, time in the operating room during the learning curve, and equipment associated with the technique. Though to date no specific, prospective, randomized studies have compared the costs of ESVH versus open saphenectomies, Brandt and associates performed a retrospective analysis of 1,909 Medicare patients who had undergone either ESVH or open saphenectomy and compared the costs associated with wound complications in both subsets of patients.¹⁸ They concluded that there appeared to be a trend toward lower treatment costs per patient and less re-source utilization with ESVH when compared to open saphenectomy. Furthermore, extrapolation of data from studies that have demonstrated shorter hospitalizations suggests that the cost effectiveness of ESVH is superior to that of conventional saphenectomies in cardiac surgical patients.¹⁹ Typical ESVH kits are currently priced from $400 to $700, which is significantly less than the cost incurred by staying in an ICU bed one extra day, let alone the cumulative costs of remaining hospitalized one extra day.

Endoscopic radial artery harvesting In 1989, Acar detected patent 18-year-old radial artery grafts, which had previously demonstrated angiographic occlusion.²⁰ A resurgence was seen in the use of the radial artery as a conduit for CABG, with the hope that a conduit superior to the greater saphenous vein would be found. Subse-quently, more patients began receiving linear incisions on the forearm from open radial artery harvesting. Although the infection rates of these incisions were significantly lower than those for open saphenectomies,²⁰ the incisions were long and unsightly. Anecdotal reports emerged of patients (particularly women) who refused utilization of their radial artery as a conduit for CABG because of unwillingness to accept the incision.

In 1998, Terada and colleagues first described endoscopic radial artery harvesting (ERAH) in five patients.²¹ Utilizing a retractable scope sheath, 4-mm/30-degree endoscope, and bipolar electrocautery, the approach consisted of two transverse 2-cm incisions in the forearm and one mid-arm helper incision with dissection starting proximally in the antecubital fossa and concluding distally at the wrist. Since that time, the technique has been refined to the current method, which is typically performed through one 2- to 3.5-cm incision slightly proximal and medial to the radial styloid (see Figure 4). Dissection is characteristically started distally at the wrist incision and advances proximally to the antecubital fossa. Instrumentation consists of ultrasonic harmonic coagulating shears or bipolar electrocautery, tailored subcutaneous retractors, and vessel dissectors.

Although the learning curve for ERAH can be steep, the benefits include significantly better cosmesis and may also include decreased morbidity compared to open radial artery harvesting. The cosmetic appearance is felt by many to have a two-fold benefit. First and most obvious is overall postoperative patient satisfaction, which cannot be understated. Of additional value, however, is its potential impact on the willingness of patients to accept radial artery harvesting who otherwise may have refused it because of the unpleasant cosmetic appearance associated with open radial artery harvesting. Over the past 2 years, ERAH has continued to increase in popularity and is now the preferred method of radial artery harvesting at the author’s institution.

Endoscopic internal thoracic artery harvesting with robotic assistance In 1986, Loop and colleagues demonstrated that utilization of the left internal thoracic artery (LITA) in CABG conferred the highest long-term survival rate, lowest incidence of cardiac events, and lowest incidence of reoperation for patients compared to those receiving vein grafts only.²² For this reason, LITA harvesting for CABG soon became the standard in most surgical myocardial revascularization procedures.

Between September 1998 and February 2000, 45 consecutive patients underwent robotic-assisted ITA harvest at the University of Western Ontario, London Health Sciences Centre, London, Ontario.²³ With the left lung collapsed, Kodera and colleagues harvested ITAs with CO₂ insufflation through three 5-mm ports in the left chest. The average harvest time was 57.8 ± 23.2 minutes, with measured intraoperative arterial Doppler flows of 34.3 ± 20.5 mL/min.

The achievements of Kodera and associates demonstrate the untapped potential of robotic assistance in minimally invasive cardiac surgery. This technique opened the door for future applications of robotic assistance in cardiac surgery beyond vessel harvesting, including deployment of distal anastomotic devices, valvular repairs, and placement of left ventricular leads for cardiac resynchronization therapy.

Complications associated with EVH

Complications, although uncommon, can occur with EVH (see Table 1). Mostcomplications are related more to the harvesting of the vessel itself than to the way in which the vessel is harvested and accordingly may also be seen with the conventional open technique, the BT, and MIVH.

ESVH complications The most common complication associated with ESVH is donor leg edema. Vein harvesting reduces the number of venous drainage routes from the lower extremity. The outcome is delayed venous emptying and increased intravenous hydrostatic pressure, which in turn favor unilateral lower extremity peripheral edema. Resolution is time dependent and based on the development of collateral venous pathways. An additional cause of edema is related to division of lymphatics in the lower extremity, which is more commonly seen with open vein harvesting than with ESVH. Less common complications associated with ESVH include hematoma and seroma formation in the endoscopic surgical tunnel, incisional cellulitis, frank infection involving the surgical tunnel, and below-knee skin paresthesia. Paresthesias are secondary to division of the saphenous nerve, which can often encircle the greater saphenous vein in the lower leg.

ERAH complications Complications associated with ERAH are analogous to those with ESVH, with the exception of peripheral edema and infection. Paresthesias from ERAH are characteristically related to stretching or division of a superficial branch of the radial nerve through wound manipulation, wound closure, or inadvertent cauterization. Symptoms consist of numbness to the thenar eminence and/or on the dorsal aspect of the hand and numbness to the proximal portion of the first three digits. Most symptoms are transient.

Endoscopic ITA harvesting complications Left sternal border and left anterior thorax paresthesias and hyperesthesias are the most common complications related to ITA harvesting. These typically result from the close proximity of the ITA to its accompanying sensory nerve. As the nerve regenerates, the paresthesias often convert to hyperesthesia, both of which eventually resolve.

Conclusion

From the first coronary artery bypass procedure by Favoloro and Effler in 1967² until one of the first attempts at less invasive saphenous vein harvesting in 1983 by Rashid and colleagues,²⁴ the morbidity and patient dissatisfaction associated with vessel harvesting for CABG were accepted as a component of coronary revascularization. Soon, however, those performing coronary revascularization procedures realized the benefits of laparoscopic general surgical procedures and imported these to cardiac surgical procedures in the form of vessel harvesting. It quickly became apparent that the morbidity and patient dissatisfaction associated with vessel harvesting was not a mandate. However, creating techniques that would not compromise the quality of the vessel or extend the expected operative time was considered to be of paramount importance and ultimately proved to be difficult. Nevertheless, with operator perseverance and the peer-review process, vessel harvesting progressed from a conventional approach to one relying totally on endoscopic techniques, and these goals were achieved. Further refinements of current techniques continue to emerge and will likely result in continued validation of the benefits associated with EVH in CABG.  

The author would like to thank W. Douglas Boyd, MD, for his contribution to this paper.

© 2007 Haymarket Media, Inc. and the American Academy of Physician Assistants. All rights reserved.
Use of jaapa.com subject to License agreement. Please read our Disclaimer and Privacy policy.