Saphenous vein harvesting techniques for coronary artery bypass grafting: a systematic review and meta-analysis

No-touch saphenous vein: current understanding of the conduit 'less handled'

PURPOSE OF REVIEW

The no-touch technique is an established method to harvest the saphenous vein (NT-SV), which is the most commonly used conduit in coronary artery bypass grafting. Herein, we summarize the foundational evidence, as well as highlight recent innovations and ongoing clinical trials involving NT-SV.

RECENT FINDINGS

Through preservation of perivascular tissue for atraumatic handling and omission of manual distension, the NT-SV maintains endothelial nitrous oxide synthase levels and experiences less vascular smooth muscle cell activation, which translates to slower progression of atherosclerosis and less size mismatch of the graft and target vessel. These biomolecular advantages allow NT-SV to provide superior graft patency compared to conventional skeletonized saphenous vein and approximating that of the radial artery. Nonetheless, the clinical benefits of NT-SV for mortality and reduction in major adverse cardiac and cerebrovascular events are insufficiently studied in the long-term. The drawback of NT-SV is the short-term harvest site complications, which may potentially be addressed by the advent of endoscopic no-touch technique.

SUMMARY

NT-SV is a promising conduit, and its role will be further clarified in upcoming clinical trials and as follow-up lengthens. However, conduit selection and harvest technique should ultimately be personalized to the individual patient.

A Comprehensive Clinical Outcome Analysis of Endoscopic Vessel Harvesting for Coronary Artery Bypass Surgery

Background: The long saphenous vein is routinely used for coronary bypass graft (CABG) surgery, and two primary techniques are commonly utilized: endoscopic vessel harvesting (EVH) and open vessel harvesting (OVH). The aim of this study was to compare the clinical outcomes of the EVH and OVH techniques used for CABG within the confines of a tertiary hospital. Methods: The clinical data of all patients subjected to either EVH or OVH for CABG surgery between 2014 and 2018 were retrospectively analyzed. Statistical analysis was performed to discern variations in the rates of postoperative complications between EVH and OVH. Results: A cohort of 1884 individuals were included in this study, 75.3% of whom underwent EVH. Notably, the incidence of postoperative leg wound complications was significantly different between the patients who underwent OVH and the patients who underwent EVH, with incidence rates of 18.6% and 32%, respectively (p < 0.001). Leg wound complications (p < 0.001; OR 1.946; 95% CI 1.528-2.477) and leg wound infections (p = 0.050, OR 1.517, 95% CI 0.999-2.303) were significantly associated with OVH. Moreover, leg wound hematoma (p = 0.039, OR = 0.402, 95% CI = 0.169-0.957) and EVH were strongly associated. Conclusions: The large sample of patients and the inclusion of a range of Asian ethnic groups provided notable insights into postoperative complications related to different modalities. EVH was associated with a lower incidence of postoperative leg wound complications, which suggests that EVH is a better modality for those undergoing CABG surgery.

Linking the region-specific tissue microstructure to the biaxial mechanical properties of the porcine left anterior descending artery

Coronary atherosclerosis is the main cause of death worldwide. Advancing the understanding of coronary microstructure-based mechanics is fundamental for the development of therapeutic tools and surgical procedures. Although the passive biaxial properties of the coronary arteries have been extensively explored, their regional differences and the relationship between tissue microstructure and mechanics have not been fully characterized. In this study, we characterized the passive biaxial mechanical properties and microstructural properties of the proximal, medial, and distal regions of the porcine left anterior descending artery (LADA). We also attempted to relate the biaxial stress-stretch response of the LADA and its respective birefringent responses to the polarized light for obtaining information about the load-dependent microstructural variations. We found that the LADA extensibility is reduced in the proximal-to-distal direction and that the medial region exhibits more heterogeneous mechanical behavior than the other two regions. We have also observed highly dynamic microstructural behavior where fiber families realign themselves depending on loading. In addition, we found that the microstructure of the distal region exhibited highly aligned fibers along the longitudinal axis of the artery. To verify this microstructural feature, we imaged the LADA specimens with multi-photon microscopy and observed that the adventitia microstructure transitioned from a random fiber network in the proximal region to highly aligned fibers in the distal region. Our findings could offer new perspectives for understanding coronary mechanics and aid in the development of tissue-engineered vascular grafts, which are currently limited due to their mismatch with native tissue in terms of mechanical properties and microstructural features. STATEMENT OF SIGNIFICANCE: The tissue biomechanics of coronary arteries is fundamental for the development of revascularization techniques such as coronary artery bypass. These therapeutics require a deep understanding of arterial mechanics, microstructure, and mechanobiology to prevent graft failure and reoperation. The present study characterizes the unique regional mechanical and microstructural properties of the porcine left anterior descending artery using biaxial testing, polarized-light imaging, and confocal microscopy. This comprehensive characterization provides an improved understanding of the collagen/elastin architecture in response to mechanical loads using a region-specific approach. The unique tissue properties obtained from this study will provide guidance for the selection of anastomotic sites in coronary artery bypass grafting and for the design of tissue-engineered vascular grafts.

Radial artery or saphenous vein for Coronary artery bypass grafitng

Coronary artery disease (CAD) is the most common cardiovascular disease worldwide, affecting over 18 million American adults. Coronary artery bypass grafting (CABG) is the standard of care for patients with left main or triple vessel CAD. Historically, the saphenous vein (SV) has been utilized to bypass the majority of the coronary vessels in patients undergoing CABG, but more recent data suggest that the use of the radial artery (RA), rather than the SV, is associated with improved cardiac outcomes and better survival. The aim of this review is to summarize the current literature on the use of RA and SV for CABG in patients with multivessel CAD.