Endoscopic vessel harvesting in coronary artery bypass graft surgery

An Artificial Cadaveric Leg Blood Flow System for Endoscopic Vein Harvesting Simulation

Despite being the most common training model for endoscopic vein harvesting, cadaveric legs are limited by their absence of blood flow, resulting in a faded vascular appearance. Because the saphenous vein and the surrounding tissue seem less distinguishable, dissection of the saphenous vein and bipolar coagulation of its branches becomes increasingly inefficient and difficult. An inexpensive artificial blood flow system was developed to overcome this limitation. A cadaveric leg was thawed to a soft and yielding degree, and the saphenous vein was dissected medial and proximal to the medial malleolus. An artificial blood solution was prepared by dissolving 4% protein powder, red dye, and a contrast agent—for x-ray visualization—in saline. The solution was perfused through the saphenous vein and artery. The open ends of the vessels were temporarily clamped after the perfusion had been completed. Blood flow within the vessels was confirmed via angiography and endoscopic visualization of the leg's vessels. A bleeding effect was observed when the saphenous vein was perforated or when a vascular branch was transected. Conversely, a tight seal indicated successful bipolar coagulation of a branch, providing an objective, quantifiable assessment parameter. The artificial blood flow system helps overcome the limitations of the cadaveric leg, creating a more realistic and inexpensive model for endoscopic vein harvesting simulation training.

The use of minimally invasive videoscopic technique in large vessel and cardiac surgery. Does the potentially increased difficulty bring benefits to the patient?

We present the clinical case of a 63-year-old patient who underwent in the Department of Cardiac Surgery implantation of an aorto-bifemoral graft prosthesis and coronary artery bypass revascularization with application of less invasive off-pump technique. Graft selection (arterial grafts, venous grafts) is very important during qualification for coronary artery bypass revascularization. Minimally invasive saphenous vein harvesting was performed during the presented case. The endoscopic technique of vein harvesting is a relatively rarely applied technique during myocardial revascularization surgery. The concept of minimally invasive videoscopic technique is presented. There is a discussion on why the team decided to prolong duration of the case consisting of two major operations performed simultaneously. Minimally invasive videoscopic technique may have a significant positive impact on postoperative outcome in a selected group of patients.

Prevention of vessel desiccation and maintenance of normal morphology during endovascular harvesting using humidified warmed gas

Dry, cold CO₂ gas was found to cause tissue damage during endovascular harvest. The use of warmed, humidified CO₂ gas appeared to maintain vessel morphology and integrity during endovascular harvest by preventing tissue desiccation.

Background and Objectives:

Endoscopic vessel harvesting (EVH) traditionally uses carbon dioxide (CO₂) gas for insufflation. The CO₂ based on government regulations is bone dry and room temperature. All previous EVH studies use this type of unconditioned gas. It is hypothesized that by changing the quality of CO₂ gas differences may occur that are attributable to dry gas versus wet gas exposure.

Methods:

A comparison of the effect(s) of traditional dry CO₂ gas compared to humidified exposure was done using a porcine model and evaluated in a double-blind randomized controlled fashion.

Results:

Vessels exposed to traditional dry cold gas had morphologic and structural changes noted on histologic evaluation. This included desiccation changes of the tunica adventitia desiccation and tunica media collagen and elastin. Vessels exposed to dry gas showed 10% to 12% contraction and constriction with tortuous changes to the intima and endothelial lining that were progressive with increasing volumes of gas exposure. No desiccation or morphologic changes were seen with humidified warmed gas produced using the VesselGuardian.

Conclusions:

Traditional dry cold CO₂ caused vascular tissue damage extending from the adventitia to intima, changing the vessel in morphologic and structural configuration. With the VesselGuardian humidified warmed, gas maintained vessel morphology and integrity by preventing desiccation. Changing the quality of CO₂ from dry and cold to wet and warm may offer clinical utility for a better quality conduit for coronary artery bypass graft procedures.

Initial Experience with Endoscopic Saphenous Vein Harvesting for Coronary Artery Bypass Graft ing in Chinese Patients

<p><b>Objective:</b> We aimed to investigate the initial experience of endoscopic vein harvesting (EVH) for coronary artery bypass grafting (CABG) in Chinese patients.</p><p><b>Methods:</b> Forty patients scheduled for isolated CABG were prospectively randomized into an EVH group (n = 20) and an open vein harvesting (OVH) group (n = 20). Clinical data were collected, and all of the vein grafts were assessed by macroscopic appearance, histologic quality (endothelial integrity), and functional characteristics of endothelial nitric oxide synthase.</p><p><b>Results:</b> The 2 groups were similar with respect to hospital mortality (EVH group, 0; OVH group, 1; <i>P</i> = 1). There were no postoperative myocardial infarctions in either group and no deaths or reinterventions in either group during the follow-up period. Harvesting times in the 2 groups were similar (EVH, 12.15 � 2.32 min; OVH, 12.55 � 2.11 min; <i>P</i> = .571). Three patients in the EVH group were converted to a partly open or skin-bridge technique. Electrocautery at least 2 mm distal to the origin of the side branch was the safety margin.</p><p><b>Conclusions:</b> The use of EVH in Chinese patients was not related to adverse events and may be safely used for CABG procedures. Preoperative duplex mapping, systemic heparinization before harvesting, minimal surgical manipulation, and sectioning of side branches at least 2 mm distal to the origin may help improve the quality of vein grafts harvested with EVH and maximize the benefit of this less-invasive technique.</p>

Endoscopic versus open vein-graft harvesting in coronary-artery bypass surgery

BACKGROUND

Vein-graft harvesting with the use of endoscopy (endoscopic harvesting) is a technique that is widely used to reduce postoperative wound complications after coronary-artery bypass grafting (CABG), but the long-term effects on the rate of vein-graft failure and on clinical outcomes are unknown.

METHODS

We studied the outcomes in patients who underwent endoscopic harvesting (1753 patients) as compared with those who underwent graft harvesting under direct vision, termed open harvesting (1247 patients), in a secondary analysis of 3000 patients undergoing CABG. The method of graft harvesting was determined by the surgeon. Vein-graft failure was defined as stenosis of at least 75% of the diameter of the graft on angiography 12 to 18 months after surgery (data were available in an angiographic subgroup of 1817 patients and 4290 grafts). Clinical outcomes included death, myocardial infarction, and repeat revascularization. Generalized estimating equations were used to adjust for baseline covariates associated with vein-graft failure and to account for the potential correlation between grafts within a patient. Cox proportional-hazards modeling was used to assess long-term clinical outcomes.

RESULTS

The baseline characteristics were similar between patients who underwent endoscopic harvesting and those who underwent open harvesting. Patients who underwent endoscopic harvesting had higher rates of vein-graft failure at 12 to 18 months than patients who underwent open harvesting (46.7% vs. 38.0%, P<0.001). At 3 years, endoscopic harvesting was also associated with higher rates of death, myocardial infarction, or repeat revascularization (20.2% vs. 17.4%; adjusted hazard ratio, 1.22; 95% confidence interval [CI], 1.01 to 1.47; P=0.04), death or myocardial infarction (9.3% vs. 7.6%; adjusted hazard ratio, 1.38; 95% CI, 1.07 to 1.77; P=0.01), and death (7.4% vs. 5.8%; adjusted hazard ratio, 1.52; 95% CI, 1.13 to 2.04; P=0.005).

CONCLUSIONS

Endoscopic vein-graft harvesting is independently associated with vein-graft failure and adverse clinical outcomes. Randomized clinical trials are needed to further evaluate the safety and effectiveness of this harvesting technique.