Vessel harvesting is a surgical technique that may be used in conjunction with a coronary artery bypass graft (CABG). For patients with coronary artery disease, a vascular bypass may be recommended to reroute blood around blocked arteries to restore and improve blood flow and oxygen to the heart. To create the bypass graft, a surgeon will remove or "harvest" healthy blood vessels from another part of the body, either arteries from an arm or the chest, or veins from a leg. This vessel becomes a graft, with one end attaching to a blood source above and the other end below the blocked area, creating a "conduit" channel or new blood flow connection across the heart. The success of a coronary artery bypass graft may be influenced by the quality of the conduit and how it is handled or treated during the vessel harvest and preparation steps prior to grafting. Success can be measured in terms of:
The need for repeat revascularization to treat a new blockage Morbidity Mortality (minimal)
Method Coronary artery bypass graft surgery has been in practice since the 1960s. Historically, vessels—such as the great saphenous vein in the leg or the radial artery in the arm—were obtained using a traditional "open" procedure that required a single, long incision from groin to ankle, or a "bridging" technique that used three or four smaller incisions. The most minimally invasive technique is known as endoscopic vessel harvesting (EVH), often described as endoscopic vein harvesting when a saphenous vein is used. This type of procedure requires a single 2 cm incision plus one or two smaller incisions of 2–3 mm in length. Each method involves carefully cutting and sealing off smaller blood vessels that branch off the main vessel conduit prior to removal from the body. This practice does not harm the remaining blood vessel network, which heals and maintains sufficient blood flow to the extremities, allowing the patient to return to normal function without noticeable effects. There is no evidence on the risk of surgical site infection and wound dehiscence when using staples or sutures to close the wound after vein graft harvesting.
Usage Endovascular vessel harvesting (EVH) uses small incisions and specialized minimally invasive instruments to internally view, cut and seal side branches and remove the healthy blood vessel with minimal trauma to the vessel or surrounding tissues. In clinical studies, EVH has shown important benefits, including a reduced risk of infection and wound complications; less postoperative pain and swelling; and faster recovery with minimal scarring. The reduction in pain allows patients to get back on their feet and return to normal mobility much sooner, and have a reduced length of hospital stay. Thus they may be able to begin their cardiac rehabilitation program sooner. Developed in 1995, adoption of EVH accelerated in 2005 after the International Society for Minimally Invasive Cardiothoracic Surgery (ISMICS) concluded that EVH should be the standard of care for vessel harvest. EVH is now the de facto standard of care, and is performed at most hospitals in the United States. However, a 2009 study published by Dr. Renato Lopes et al. in the New England Journal of Medicine concluded that the clinical outcomes of EVH were inferior to open vessel harvesting (OVH), prompting a flurry of articles in mainstream media. This study was performed between 2002 and 2007. Some clinicians challenged the study's conclusion, while others questioned the methodology of the study. Other seasoned clinicians wondered if EVH adoption and practitioners' experience have affected the data, as practitioners' experiences, techniques and technologies have evolved since the study began in 2002. Many clinicians called for more long-term studies to be conducted. In randomized clinical trials as well as other studies looking specifically at EVH, the endoscopic harvesting technique has been found to offer comparable graft patency at six months—meaning that, in these studies, EVH did not compromise the grafted vessel's ability to remain open and unblocked. In 2011, a large study by Dr. Lawrence Dacey et al. was published in Circulation supporting the use of endoscopic vessel harvesting in cardiac surgery. The study compared more than 8,500 propensity-adjusted patients and revealed that EVH significantly reduced wound complications without compromising long-term survival or freedom from repeat revascularization. These findings contradicted the conclusion drawn by Lopes et al. that EVH is inferior to OVH with respect to long-term survival. EVH was not associated with increased mortality or need for repeat revascularization at four years follow up. An accompanying editorial in Circulation further concluded that "EVH is here to stay" and predicted that "OVH will be obsolete in a few years." Dacey's study supported the findings of two other large, observational studies and reaffirmed the significant benefits of EVH in reducing wound complications. Totaling more than 16,000 patients tracked, these three studies provide strong evidence that EVH is a safe and viable technique to use to obtain a saphenous vein conduit for CABG surgery. Additional support that EVH does not adversely affect the integrity of the conduit and has equivalent clinical outcomes has recently been published by Krishnamoorthy et al. in Circulation.
Conduit quality for successful vessel harvesting As mentioned above, the success of CABG surgery may be influenced by the quality of the "conduit" vessel and how it is handled or treated during the harvest and preparation steps prior to grafting. The harvested blood vessel used in coronary artery bypass graft surgery must be free from damage to ensure proper long-term function and good patient outcomes. Conduit quality is a significant factor in long-term patient results. Conduit quality is not always visibly evident when looking at the exterior of the harvested vessel. Damage to the endothelium, the interior of the vessel, has been shown to increase the likelihood of graft occlusion or blockage. Specifically, damage can be caused during the procedure by:
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