Author + information
- Øystein Pettersen, MD∗ (, )
- Rune Wiseth, MD, PhD,
- Knut Hegbom, MD and
- Dag Ole Nordhaug, MD, PhD
- ↵∗Department of Cardiothoracic Surgery, St. Olavs University Hospital, 7006 Trondheim, Norway
Despite strong evidence for superior patency and improved clinical endpoints using arterial grafts in coronary artery bypass graft surgery, the saphenous vein (SV) is still the most widely used graft in addition to left internal mammary artery (LIMA) (1). Consequently, improving SV patency continues to be a major goal. Souza et al. (2) introduced a “no-touch” harvesting technique, reporting significantly slower progression of atherosclerosis and long-term patency comparable to that of the LIMA (2). In this technique, the SV is harvested with an extensive pedicle of surrounding tissue, aiming to preserve the entire vein wall, including the vasa vasorum. The vein is then connected to the aortic cannula to test for leakage and is stored in heparinized blood. Unfortunately, this technique has been hampered by its complexity, as well as concerns of leg wound complications and a proposed increased risk of perioperative bleeding.
We compared conventional vein harvesting to a simplified “no-touch” vein harvesting technique. Vein grafts were harvested as a pedicle with <5 mm of tissue on each side. Grafts were manually distended to check for leakage and stored in a solution of heparinized blood and saline, as in conventional vein harvesting. Our hypothesis was that the perivascular tissue contributed to reduced intimal hyperplasia compared with conventional, skeletonized veins at 6 months and subsequently improved patency at 5-year follow-up. From April 2013 to December 2014, 100 patients undergoing first time on-pump coronary artery bypass graft surgery using at least 1 SV graft were included. Patients were randomized to conventional or pedicled vein harvesting. Main exclusion criteria were insulin-dependent diabetes mellitus, smoking during the last 6 months, and serum creatinine >120 μmol/l. All patients received high-dose statin therapy and acetylsalicylic acid. The first 60 patients were offered a 6-month angiographic follow-up (mean age was 64.3 ± 6.9 years, 8 of 60 were female). Intimal hyperplasia was measured using optical coherence tomography (OCT) following conventional angiography. OCT uses near-infrared light to produce ultra-high-resolution images, enabling separate investigation of the intima and media layers of the vein wall. An OCT pullback was performed in 1 graft in each patient (Ilumien PCI Optimization System, St. Jude Medical, St. Paul, Minnesota). Intimal thickness was measured throughout the whole pullback. External investigators blinded to randomization performed offline image analysis. Full study details are available online (NCT01834846). Examples of OCT images are given in Figure 1.
All patients received a LIMA to left anterior descending artery graft in addition to 1 or more SV grafts. There was no significant difference in mean graft flow or in the number of single versus sequential grafts in the 2 study groups. A total of 54 patients underwent follow-up (conventional vein: n = 26, time to follow-up 216 ± 24 days; pedicled vein n = 28, time to follow-up: 207 ± 23 days). In the conventional group, 5 single and 21 sequential grafts supplying the left coronary artery were examined using OCT. In the pedicled group, 6 single and 21 sequential vein grafts supplying the left coronary artery and 1 single graft supplying the right coronary artery were examined. OCT revealed significant differences in mean intima thickness between the 2 study groups (conventional vein 0.36 ± 0.11 mm; pedicled vein 0.27 ± 0.06 mm; p < 0.001). Additionally, the intima of pedicled vein grafts were more uniform in thickness, with a significantly lower SD of the intima thickness along the length of the grafts (conventional vein: 0.06 ± 0.04 mm; pedicled vein: 0.04 ± 0.02 mm; p = 0.035). As expected at this early follow-up, there was no difference in occlusion rates (conventional vein: 6 of 50; pedicled vein: 4 of 50).
Our study demonstrates that the pedicled vein graft harvesting technique has a significant effect on intimal hyperplasia as early as 6 months post-operatively. It remains to be seen whether this difference translates into a difference in long-term patency. However, it is clear that the intimal hyperplasia is an early and important stage in vein graft disease with the areas of intimal hyperplasia prone to develop atherosclerosis at longer term (3). Mid-term occlusion rates will be investigated at the 5-year follow-up. Additional data from the 5-year follow-up will provide information on how the intima in these grafts develops over time.
Please note: This study was funded by the Department of Cardiology and the Department of Cardiothoracic Surgery at St. Olav’s University Hospital, Trondheim, Norway; the Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology; and the Norwegian Health Association (Nasjonalforeningen for Folkehelsen). The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- American College of Cardiology Foundation