Introduction
What is total arterial revascularisation?
Have you ever heard of total arterial revascularization (TAR)? You most likely have not. TAR is a surgical approach used in coronary artery bypass grafting (CABG). The process includes using different arterial grafts, such as the radial and internal mammary arteries, to bypass blocked coronary arteries. This approach aims to improve long-term outcomes.1
What is the significance of TAR in CABG procedures?
Total arterial revascularization provides a different approach to conventional CABG as it utilises multiple arterial grafts, potentially improving overall patient outcomes and the patency of the grafts.1
Continue reading this article to learn more about total arterial revascularization, especially if you or someone you know may need to undergo it.
Rationale for total arterial revascularisation
Comparison with traditional CABG
Single arterial graft vs multiple arterial graft
Traditionally, in CABG procedures, a single arterial graft is used, whereas in total arterial revascularisation, multiple arterial grafts are used.1 Saphenous vein grafts (SVG) and the left internal mammary artery (LIMA) are used in around 95% of CABG procedures.1 However, using saphenous vein grafts comes with some problems:
- Short-term complications: Vein grafts are associated with a significant risk of postoperative graft thrombosis, with as many as 12% of occlusion cases within the first six months following CABG. This makes antiplatelet and antithrombotic medication extremely important.2
- Delayed complications: almost all vein grafts are predisposed to intimal hyperplasia within the first year of grafting due to the high thrombosis rate.2
- Late complications: thrombosis and intimal thickening will inevitably lead to graft atherosclerosis. Pharmacological therapies, including lipid-lowering medications, have been demonstrated to enhance graft patency. However, within ten years of the introduction of SVG, about 10% of patients required repeat revascularisation due to atherosclerosis, which continues to be the leading cause of poor patency and graft failure.2
Total arterial revascularisation exclusively uses arterial conduits without saphenous vein grafts.1 As multiple arterial grafts are used, blood flow is improved, which may have better long-term patency rates. CABG performed with multiple arterial grafts (MAG) has been shown to have better clinical outcomes than using a single arterial graft3, especially in people assigned female at birth4 (AFAB). People with AFAB generally have worse outcomes following CABG, but when MAG has been used in CABG, the long-term outcomes are improved.4
Long-term outcomes and survival rates
For patients requiring CABG who have a reasonable expectation of survival, total arterial revascularisation may be the preferred surgery since it has been linked to greater long-term freedom from major adverse cardiac and cerebrovascular events (MACCE), mortality, and myocardial infarction.5
Around 30% of patients referred to cardiac surgery have diabetes. Patients with diabetes have a 2 to 4-fold increased risk of developing coronary heart disease, with ischemic coronary heart disease being a leading cause of diabetes-related deaths. Diabetic patients are prone to atherosclerosis progressing rapidly, which leads to an increased likelihood of them requiring revascularization. Evidence has shown that the use of total arterial revascularisation in diabetic patients has improved overall outcomes.6
Types of arterial grafts used in total arterial revascularization
Internal mammary artery (IMA)
The internal mammary artery (IMA) is also known as the internal thoracic artery (ITA),7 so if you do some research and see ITA, it is the same as IMA, and if you see ‘R’ or ‘L’ before IMA, it is simply stating right or left. It is an artery that supplies the anterior chest wall and the breast.7
Advantages and benefits
The internal mammary artery (IMA) is the gold standard conduit that significantly improves patients' survival and short- and long-term results after CABG surgery. Approximately 90% of grafts are still free of significant stenosis after ten years, demonstrating the extremely high long-term patency rate of IMA bypass conduits. There are a few key factors that are responsible for the long-term patency of IMA bypass:7
- Resistance against atherosclerosis's development7
- Reactivity to vasodilators7
- Low thrombotic threshold velocity7
- High flow velocities – mean flow is 3x that of SVG7
These factors are why IMA is used in surgery and why it is associated with improved long-term survival and a reduced risk of cardiac events.
Clinical evidence supporting IMA use
Many studies have shown the efficacy of IMA in TAR, the higher graft patency rates, and the improved long-term survival. In the third decade following CABG, it has been demonstrated that up to 80% of ITA conduits are failure-free.8
Radial Artery
Characteristics and suitability
The radial artery (RA) is the second most used graft after IMA due to its ease of harvesting and larger diameter.9 Studies have shown that the radial artery has demonstrated low rates of graft failure and high rates of short, and long-term patency.2 This makes the radial artery suitable for use in TAR.
In terms of surgery, RA has a reduced operation time,1 which may benefit the patient. When harvested endoscopically, the incision size and pain are reduced.9
Comparative effectiveness with other grafts
The radial artery has a similar patency to IMA and is superior to SVG. It also has similar clinical outcomes to IMA used in TAR2. So, from this, we can say that using the RA in TAR will have a high chance of success and a better patient outcome than traditional CABG.
Surgical techniques used in TAR
Sequencing grafting
Sequential grafting creates several distal anastomoses for each conduit segment used, resulting in two or more distal anastomoses for each proximal anastomosis. This technique is thought to improve blood flow in the graft and its patency. Furthermore, it improves survival and outcomes.10
Composite Y graft
A composite Y graft is where two arterial conduits are combined – either the left or right IMA with the radial artery.11 Typically, the left IMA is used for left anterior descending (LAD) anastomosis as it is believed to be the better conduit.12 Combining the two creates a Y shape, hence it being called a Y graft.
Patient selection criteria
Factors influencing the choice of TAR
- Age – age is not an issue in TAR13; however, younger patients may benefit more than elderly patients as they would have a longer life expectancy
- Co-morbidities – co-morbidities could influence the choice of TAR; however, depending on the co-morbidities, they could be dealt with by medication.13
Challenges and considerations
Complications that might occur during TAR:
- Inability to control any bleeding14
- Compromising graft patency14
- Damage to artery14
- Deep sternal wound infection (DSWI)14
Summary
In Coronary Artery Bypass Grafting (CABG), Total Arterial Revascularization (TAR) utilises radial and internal mammary artery grafts to bypass blocked coronary arteries. It uses arteries from the arm (radial) and chest (internal mammary) to bypass blockages. What makes TAR special is that it only uses these artery paths, and it could be better than the usual method of CABG.
TAR seems to have better long-term results and higher survival rates, which is especially good news for people with diabetes and a higher risk of heart problems. The internal mammary artery (IMA) plays a big role in TAR and is known for being top-notch, fighting against artery problems and keeping a strong blood flow, ultimately helping people live longer.
When choosing TAR for a patient, clinicians consider factors like age and other health issues. Surprisingly, age doesn't stop someone from getting TAR. But like any procedure, there could be issues, such as bleeding, graft problems, or infections in the chest area.
As we keep exploring the benefits of TAR and finding ways to improve it, there's a chance it could become the go-to surgical method. This shift could completely change how clinicians approach heart surgery, offering patients a stronger and longer-lasting solution for heart issues. TAR shows a lot of potential for the future of fixing arteries of the heart.
TAR shows promise in Coronary Artery Bypass Grafting (CABG), providing enhanced long-term outcomes and fewer complications compared to traditional methods. In simple terms, TAR looks really promising for fixing the heart arteries, and it seems to be better than the usual way of doing things.
References
- Ren J, Royse C, Royse A. Late clinical outcomes of total arterial revascularization or multiple arterial grafting compared to conventional single arterial with saphenous vein grafting for coronary surgery. J Clin Med [Internet]. 2023 Mar 27;12(7):2516. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10094905/
- Samak M, Fatullayev J, Sabashnikov A, Zeriouh M, Schmack B, Ruhparwar A, et al. Total arterial revascularization: bypassing antiquated notions to better alternatives for coronary artery disease. Med Sci Monit Basic Res [Internet]. 2016 Oct 4;22:107–14. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5063431/
- Davierwala PM, Gao C, Thuijs DJFM, Wang R, Hara H, Ono M, et al. Single or multiple arterial bypass graft surgery vs. percutaneous coronary intervention in patients with three-vessel or left main coronary artery disease. European Heart Journal [Internet]. 2022 Apr 1;43(13):1334–44. Available from: https://academic.oup.com/eurheartj/article/43/13/1334/6354120
- Robinson NB, Lia H, Audisio K, Soletti G, Demetres M, Leonard JR, et al. Coronary artery bypass with single versus multiple arterial grafts in women: a meta-analysis. J Thorac Cardiovasc Surg [Internet]. 2021 Aug 10;165(3):1093–8. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8828799/
- Rocha RV, Tam DY, Karkhanis R, Wang X, Austin PC, Ko DT, et al. Long-term outcomes associated with total arterial revascularization vs non–total arterial revascularization. JAMA Cardiol [Internet]. 2020 May;5(5):507–14. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7042852/
- Di Bacco L, Repossini A, Muneretto C, Torkan L, Bisleri G. Long-term outcome of total arterial myocardial revascularization versus conventional coronary artery bypass in diabetic and non-diabetic patients: a propensity-match analysis. Cardiovascular Revascularization Medicine [Internet]. 2020 May;21(5):580–7. Available from: https://www.sciencedirect.com/science/article/pii/S1553838919306438
- Ahmed I, Yandrapalli S. Internal mammary artery bypass. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023. Available from: http://www.ncbi.nlm.nih.gov/books/NBK560835/
- Papakonstantinou NA, Baikoussis NG. Total arterial revascularization: A superior method of cardiac revascularization. Hellenic Journal of Cardiology [Internet]. 2016 May;57(3):152–6. Available from: https://www.sciencedirect.com/science/article/pii/S1109966616300732
- Vervoort D, Elbatarny M, Rocha R, Fremes SE. Reconstruction technique options for achieving total arterial revascularization and multiple arterial grafting. Journal of Clinical Medicine [Internet]. 2023 Mar 15;12(6):2275. Available from: https://www.mdpi.com/2077-0383/12/6/2275
- Saleh AEEH, Salah RM, Makram M. Sequential anastomosing technique in coronary artery bypass grafting surgery cabg, efficacy and short term outcome. The Medical Journal of Cairo University [Internet]. 2022 Jun;90(6):689–93. Available from: https://mjcu.journals.ekb.eg/article_253118.html
- Doha O, Felix F, Andreas M, Serghei C, Axel H, Gregor W, et al. Total arterial revascularization with radial artery and internal thoracic artery t-grafts is associated with superior long-term survival in patients undergoing coronary artery bypass grafting. Ann Thorac Cardiovasc Surg [Internet]. 2020 Jan 18;26(1):30–9. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7046926/
- Limanto DH, Chang HW, Kim DJ, Kim JS, Park KH, Lim C. Coronary artery size as a predictor of Y-graft patency following coronary artery bypass surgery. Medicine (Baltimore) [Internet]. 2021 Jan 15;100(2):e24063. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7808508/
- Tatoulis J. Total arterial coronary revascularization—patient selection, stenoses, conduits, targets. Annals of Cardiothoracic Surgery [Internet]. 2013 Jul;2(4):499–506. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3741872/14. Total arterial coronary grafting: outcomes, concerns and controversies. Vessel Plus [Internet]. 2019 Jul 11;3:23. Available from: https://www.oaepublish.com/articles/2574-1209.2019.05