The aim of this study is to investigate the histological and immunohistochemical findings of the saphenous vein graft, to rule out endothelial damage as a direct result of manipulation or instrumentation by endoscopic and open conventional harvesting methods. Furthermore, to investigate if there are any differences in the surgical site infection, cardiac event and functional status between the two harvest strategies at 1-year of follow-up.

BACKGROUND Ischemic heart disease is the leading cause of death globally that accounts for about 7.4 million mortalities worldwide annually as published by the World Health Organization. Coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) are the options for revascularization in patients suffering from coronary artery disease (CAD). The choice of the most appropriate modality is affected by the clinical presentation, comorbidities, anatomical complexity of the CAD, and baseline characteristics of the patient. Although advances in PCI with drug-eluting stents have provide good outcomes, CABG remains an important revascularization strategy in the treatment of CAD.

The initial experience of using saphenous vein as coronary bypass conduits was first published from the Cleveland clinic in 1967. Minimally invasive endoscopic vein harvest (EVH) was first reported in 1996 as an alternative to open vein harvest (OVH). An endoscope is introduced adjacent to the vein, allowing its dissection under direct vision via a small incision. Over the last decade, EVH has become the preferred technique for conduit harvest in many cardiothoracic centers owing to the overall reduction in complications compared with OVH and the obvious cosmetic advantage. However, concerns persist regarding the risk of microscopic damage incurred during EVH, and the consequences of this for long-term graft patency.

OBJECTIVES The aim of this study is to investigate the histological and immunohistochemical findings of the saphenous vein graft, to rule out endothelial damage as a direct result of manipulation or instrumentation by endoscopic and open conventional harvesting methods. Furthermore, to investigate if there are any differences in the surgical site infection, cardiac event and functional status between the two harvest strategies at 1-year of follow-up.

METHODS This is a prospective, single-center randomized controlled trial conducted in the department of cardiac surgery at the Sheba Medical Center. It will include a sample size of 50 patients (randomization ratio 1:1), who are planned to undergo an elective isolated CABG surgery, and a vein graft is necessary for the revascularization.

Inclusion Criteria:

• Male or female patients over the age of 18;
• Patients with ischemic heart disease who are planned to undergo CABG surgery;
• A vein graft in necessary for the revascularization;
• There is no indication for one specific method for vein harvesting;
• Informed consent obtained.

Exclusion Criteria:

• Patients who undergo a non-elective surgery
• Concomitant procedures during the CABG surgery;
• Any known infection in the past 6 months;
• Evidence of vein thrombosis in an ultrasound study prior to surgery;
• Morbid obesity patients;
• Patients with peripheral vascular disease;
• Patients who would gain from one technique more than the other by any reason (according to the surgeon or investigator opinion);
• Severe primary mitral and aortic valve stenosis or regurgitation;
• Patients who have undergone a previous cardiac surgery from any kind;
• Patients who underwent any surgery in the lower extremities in the past (i.e. orthopedic, vascular, etc.);
• Any serious disease likely to interfere with the conduct of the study;
• Participation in other clinical trial;
• Patients geographically not stable or unavailable for follow-up.