The radial artery: An important component of multiarterial coronary surgery and considerations for its optimal harvest

Intra-operative and post-operative management of conduits for coronary artery bypass grafting: a clinical consensus statement of the European Society of Cardiology Working Group on Cardiovascular Surgery and the European Association for Cardio-Thoracic Surgery Coronary Task Force

The structural and functional integrity of conduits used for coronary artery bypass grafting is critical for graft patency. Disruption of endothelial integrity and endothelial dysfunction are incurred during conduit harvesting subsequent to mechanical or thermal injury and during conduit storage prior to grafting, leading to acute thrombosis and early graft failure. Late graft failure, in particular that of vein grafts, is precipitated by progressive atherogenesis. Intra-operative management includes appropriate selection of conduit-specific harvesting techniques and storage solutions. Arterial grafts are prone to vasospasm subsequent to surgical manipulation, and application of intra-operative vasodilatory protocols is critical. Post-operative management includes continuation of oral vasodilator therapy and selection of antithrombotic and lipid-lowering agents to attenuate atherosclerotic disease progression in conduits. In this review, the scientific evidence underlying the key aspects of intra- and post-operative management of conduits for coronary artery bypass grafting is examined. Clinical consensus statements for best clinical practice are provided, and areas requiring further research are highlighted.

Intra-operative and post-operative management of conduits for coronary artery bypass grafting: a clinical consensus statement of the European Society of Cardiology Working Group on Cardiovascular Surgery and the European Association for Cardio-Thoracic Surgery Coronary Task Force

The structural and functional integrity of conduits used for coronary artery bypass grafting is critical for graft patency. Disruption of endothelial integrity and endothelial dysfunction are incurred during conduit harvesting subsequent to mechanical or thermal injury and during conduit storage prior to grafting, leading to acute thrombosis and early graft failure. Late graft failure, in particular that of vein grafts, is precipitated by progressive atherogenesis. Intra-operative management includes appropriate selection of conduit-specific harvesting techniques and storage solutions. Arterial grafts are prone to vasospasm subsequent to surgical manipulation, and application of intra-operative vasodilatory protocols is critical. Post-operative management includes continuation of oral vasodilator therapy and selection of antithrombotic and lipid-lowering agents to attenuate atherosclerotic disease progression in conduits. In this review, the scientific evidence underlying the key aspects of intra- and post-operative management of conduits for coronary artery bypass grafting is examined. Clinical consensus statements for best clinical practice are provided, and areas requiring further research are highlighted.

Low Calcium-High Magnesium Krebs-Henseleit Solution Combined with Adenosine and Lidocaine Improved Rat Aortic Function and Structure Following Cold Preservation

Background and objectives: The main problem of vascular preservation is the maintenance of vessel graft quality and function following extended storage. Conventional preservation solutions such as histidine-tryptophan-ketoglutarate (HTK) solution, Phosphate-Buffer Solution (PBS), or sodium chloride 0.9% has been shown to be inadequate in preserving vascular physiological function after 3 days of cold storage. This study aimed to evaluate whether adenosine and lidocaine (AL) in a modified Krebs-Henseleit (KH) solution can preserve the function and histological structure of rat aortic rings after 6 days. Materials and Methods: Thirty-five aortic rings from male Wistar rats (200-300 g) were harvested and immediately immersed in one of the assigned cold preservation solutions: standard KH, modified KH (mod KH) with lower calcium (Ca2+) and higher magnesium content (Mg2+) with or without adenosine and lidocaine (mod KH-AL), and modified KH with AL, insulin, and melatonin (Mod KH-ALMI). The contraction and relaxation function of the aortic rings were examined using an isometric force transducer after 6 days of cold preservation. Hematoxylin and eosin staining were used to analyze the rings' histological structure. Results: Vascular contraction and relaxation functions were severely affected after a 6-day cold storage period in standard KH. Modifying the KH solution by reducing the Ca2+ and increasing the Mg2+ levels greatly recovered the vessel functions. The addition of AL or ALMI to the modified KH did not further recover vascular contractility. However, only the addition of AL to the modified KH increased the ACh-induced relaxation at 6 days when compared to the conventional KH, suggesting that endothelium preservation is improved. From histological analysis, it was found that the addition of AL but not ALMI further improved the endothelial lining and the structure of the elastic membrane layers of the preserved vessels after 6 days of cold preservation. Conclusions: The addition of AL to low calcium-high magnesium KH solution significantly enhanced endothelial preservation and improved endothelial-induced relaxation of preserved vessels after 6 days of cold storage.

Clinical and financial outcomes associated with the utilization of right internal mammary artery versus radial artery in multivessel coronary artery bypass grafting

BACKGROUND

Multi-arterial coronary bypass grafting with the left internal mammary artery as a conduit has been shown to offer superior long-term survival compared to single-arterial coronary bypass grafting. Nevertheless, the selection of a secondary conduit between the right internal mammary artery and the radial artery remains controversial. Using a national cohort, we examined the relationships between the right internal mammary artery and the radial artery with acute clinical and financial outcomes.

METHODS

Adults undergoing on-pump multivessel coronary bypass grafting with left internal mammary artery as the first arterial conduit were identified in the 2016 to 2020 Nationwide Readmissions Database. Patients receiving either the right internal mammary artery or the radial artery, but not both, were included in the analysis. Multivariable regression models were fitted to examine the association between the conduits and in-hospital mortality, as well as additional secondary outcomes.

RESULTS

Of an estimated 49,798 patients undergoing multi-arterial coronary bypass grafting, 29,729 (59.7%) comprised the radial artery cohort. During the study period, the proportion of multi-arterial coronary bypass grafting utilizing the radial artery increased from 51.3% to 65.2% (nptrend <0.001). Following adjustment, the radial artery was associated with reduced odds of in-hospital mortality (adjusted odds ratio 0.44), prolonged mechanical ventilation (adjusted odds ratio 0.78), infectious complications (adjusted odds ratio 0.69), and 30-day nonelective readmission (adjusted odds ratio 0.77, all P < .05).

CONCLUSION

Despite no definite endorsement from surgical societies, the radial artery is increasingly utilized as a secondary conduit in multi-arterial coronary bypass grafting. Compared to the right internal mammary artery, the radial artery was associated with lower odds of in-hospital mortality, complications, and reduced healthcare expenditures. These results suggest that whenever feasible, the radial artery should be the favored conduit over the right internal mammary artery. Nevertheless, future studies examining long-term outcomes associated with these vessels remain necessary.

A Superficial Anatomical Variation in the Radial Artery Renders It Unsuitable as a Graft in Coronary Revascularization

In our experience, employing a radial artery in combination with an internal thoracic artery under specific conditions represents a superior option compared to using a vein graft in coronary artery surgery. Additionally, this combination is a remarkable alternative to utilizing bilateral thoracic arteries. We had planned the left radial artery as the second target graft in two patients undergoing coronary artery bypass surgery; the left internal thoracic artery to the left anterior descending branch would be the main graft in both patients. Anatomic variation of the radial artery, which presented as a superficial radial artery in both patients, led us to forego the use of the radial artery graft. This decision aimed to ensure sufficient blood supply to the palmar arch and prevent any potential inadequacy in the length of the coronary graft. The occurrence of this variation is exceptionally rare, accounting for approximately 0.02% based on our experience with radial artery harvesting. Furthermore, globally, the documentation of photographs depicting a superficial radial artery is even more infrequent.

Angiographic Outcomes for Arterial and Venous Conduits Used in CABG

Coronary artery bypass grafting is the most commonly performed cardiac surgical procedure. Conduit selection is crucial to achieving early optimal outcomes, with graft patency being likely the main driver to long-term survival. We present a review of current evidence on the patency of arterial and venous bypass conduits and of differences in angiographic outcomes.

Characteristics of Radial Artery Coronary Bypass Graft Failure and Outcomes Following Subsequent Percutaneous Coronary Intervention

BACKGROUND

When patients with prior coronary artery bypass grafting (CABG) undergo percutaneous coronary intervention (PCI), targeting the native vessel is preferred. Studies informing such recommendations are based predominantly on saphenous vein graft (SVG) PCI. There are few data regarding arterial graft intervention, particularly to a radial artery (RA) graft.

OBJECTIVES

The aim of this study was to report the characteristics of arterial graft stenoses and evaluate the feasibility of RA PCI.

METHODS

This study included 2,780 consecutive patients with prior CABG undergoing PCI between 2005 and 2018 who were prospectively enrolled in the MIG (Melbourne Interventional Group) registry. Data were stratified by PCI target vessel. RA graft PCI was compared with both native vessel (native PCI) and SVG PCI. Internal mammary graft PCI data were reported. The primary outcome was 3-year mortality.

RESULTS

Overall, 1,928 patients (69.4%) underwent native PCI, 716 (25.6%) SVG PCI, 86 (3.1%) RA PCI, and 50 (1.8%) internal mammary graft PCI. Compared with SVG PCI, the RA PCI cohort presented earlier after CABG, less frequently had acute coronary syndrome, and more commonly had ostial or distal anastomosis intervention (P < 0.005 for all). Compared with patients who underwent native PCI, those who underwent RA PCI were more likely to have diabetes and peripheral vascular disease (P < 0.001 for both) and to present with non-ST-segment elevation myocardial infarction (P = 0.010). The RA PCI group had no perforations or in-hospital myocardial infarctions, though no significant difference was found in periprocedural outcomes compared with either native or SVG PCI. No differences were found between RA PCI and either native or SVG PCI in 30-day outcomes or 3-year mortality.

CONCLUSIONS

Presenting and lesion characteristics differed between patients undergoing arterial compared with SVG PCI, implying a varied pathogenesis of graft stenosis. RA PCI appears feasible, safe, and where anatomically suitable, may be a viable alternative to native PCI.