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.