Skeletonized gastroepiploic artery as a composite graft for total arterial revascularization

Clinical application of individualized total arterial coronary artery bypass grafting in coronary artery surgery

BACKGROUND

Total arterial revascularization is associated with increased patency and long-term efficacy and decreased perioperative morbidity and mortality and incidence of cardiac-related events and sternal wound infection compared with conventional coronary artery bypass surgery (CABG), in which the left internal mammary artery (LIMA) is typically grafted to the left anterior descending artery with additional saphenous vein grafts often used. This study determined whether these favorable clinical results could be realized at the authors’ institute.

AIM

To summarize the early efficacy and clinical experience of individualized total arterial coronary artery bypass grafting surgery.

METHODS

CABG was performed on 35 patients with non-single-vessel coronary artery disease by adopting total arterial grafts at Fourth Affiliated Hospital of Harbin Medical University between April 2016 and December 2019. LIMA was used in 35 patients, radial artery (RA) was used in 35 patients, and right gastroepiploic artery (RGEA) was used in 9 patients. Perioperative complications were observed, short-term graft patency rate was followed-up, and quality of life was assessed.

RESULTS

All patients underwent off-pump coronary artery bypass and the surgeries were successful. All of them were discharged without any complications or deaths. During the follow-up, it was found that patients’ angina symptoms were relieved and New York Heart Association classification for cardiac function was class I to class II. A total of 90 vessels were grafted with no occlusion for internal mammary artery, three occlusions for RA, and one occlusion for RGEA.

CONCLUSION

The individualized total arterial strategy based on the vessels targeting individual anatomic characteristics can achieve complete revascularization with satisfactory short-term grafting patency rate.

Composite Y Grafts From the Left Internal Mammary Artery: Current Considerations

The use of composite coronary artery bypass grafts from the left internal mammary artery (LIMA) has increased over the last 20 years. Total arterial revascularisation can be achieved with two arterial conduits and is associated with a reduced risk of stroke. However, the traditional coronary bypass graft configurations of the in situ LIMA and aorto-coronary saphenous vein grafts remain as the mainstay of coronary bypass surgery in most centres. Concerns regarding composite Y grafts relate to (1) the adequacy of a single inflow for all coronary bypass grafts; (2) the risk of compromising the LIMA flow to the left anterior descending coronary artery; (3) the effects of competitive flow on graft patency; and (4) the use of sequential coronary anastomoses. The evidence upon which these concerns are based will be discussed along with the evidence relating to the use of the various second conduit options.

Composite arterial grafting

The success of coronary artery bypass grafting, the gold standard for the treatment of multivessel coronary artery disease, is limited by poor long-term vein-graft patency. By contrast, the left internal mammary artery has been demonstrated to have a superior graft patency rate and has provided excellent clinical results. This suggests that the use of arterial conduits for coronary artery bypass grafting may be beneficial for long-term results. Recently, there has been an upsurge in the use of arterial grafts for myocardial revascularization based on the clinical advantage of the use of the left internal mammary artery as a bypass conduit. Many retrospective studies have supported the safety and the effectiveness of arterial grafting, and it has become apparent that the free arterial graft can be used as a branched or a lengthened conduit to the in situ arterial graft by adopting one or more of the several composite grafting techniques. Arterial composite grafts with or without sequential grafting techniques appear an attractive strategy as increased number of distal coronary anastomoses can be performed, with a limited number of grafts, avoiding proximal aortic anastomoses. However, concerns regarding the total dependence of the coronary bypass flow on the flow of one in situ arterial graft and technical error, resulting in compromised flow in one or both limbs of the composite graft have prevented composite arterial grafting from being universally adopted. It is expected that in the near future a prospective, multi-institutional, randomized controlled trial, to compare the short- and long-term outcomes of exclusive arterial grafting using composite and conventional aortocoronary revascularization strategies, will be undertaken to validate the safety and efficacy of composite arterial grafting.

Does a skeletonized or pedicled right gastro-epiploic artery improve patency when used as a conduit in coronary artery bypass graft surgery?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether skeletonization of the right gastro-epiploic artery (RGEA) improves graft patency in coronary artery bypass grafting (CABG). Altogether >25 papers were found using the reported search, of which 11 papers represented the best evidence to answer this clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes and results are tabulated. Four out of the 11 papers were comparative studies (skeletonized conduits vs. pedicled conduits) and four studies produced one-year follow-up data. No studies revealed long-term patency rates as there was no follow-up data beyond five years. It is important to note that the evidence in the literature is based in a Japanese population. The vast majority of the target vessel which had been grafted by the RGEA was the right coronary artery and more specifically the posterior descending artery (PDA). The association between off-pump technique, sequential grafting, skeletonization of the RGEA with the harmonic scalpel and angiographic patency has not been adequately assessed. The studies reveal excellent patency rates for both early and mid-term skeletonized RGEA conduits. Overall patency rates were 97.7% within three months, 92.4% at a mean of approximately 1 year, 91.5% at a mean of approximately 2 years, and 86.4% at 4 years. In the four comparative studies, skeletonization patency was at least comparable and in one study superior to pedicled conduits. One study revealed a higher four-year cumulative patency rate for skeletonized conduits in comparison to a previous study by the same author where pedicled grafts were used. In conclusion, patency rates exceeded 95% in 10 studies for a follow-up of up to three months postoperatively. The evidence which supports the use of a 'skeletonized' RGEA is growing and this paper demonstrates clearly that in terms of patency, a skeletonized RGEA to the PDA should be considered as a conduit for CABG surgery especially when total arterial revascularization strategy with in situ conduits and no manipulation of the ascending aorta is the treatment of choice.

Y grafting for coronary artery bypass: is it as good as single grafting?

PURPOSE OF REVIEW

The use of multiple arterial grafting has gained popularity in recent years due to its clinical advantages when compared with conventional CABG surgery. The purpose of the present review is to focus in particular on the safety and efficacy of composite Y grafting in coronary surgery.

RECENT FINDINGS

Several studies demonstrated mid-term and long-term benefits of total arterial myocardial revascularization when compared with conventional CABG, that is utilizing the left internal mammary artery and multiple veins. Nevertheless, there have been concerns whether it is safe to have a single inflow rather than multiple aorto-coronary grafts. There is evidence in literature that composite arterial grafting is nowadays a well established technique, and several configurations can be performed according to the specific patients' needs. Moreover, the use of Y grafting completely avoids aortic manipulation, especially when used in association with the off-pump technique.

SUMMARY

Composite Y grafting with the exclusive use of arterial conduits is a well tolerated and effective technique. The choice of the second arterial conduit should be tailored according to the specific patients' characteristics. The association of composite arterial grafting and off-pump technique allows a no-touch technique of the ascending aorta, thereby also minimizing the risk of neurological events.

Preoperative evaluation of the right gastroepiploic artery on multidetector computed tomography in coronary artery bypass graft surgery

BACKGROUND

The right gastroepiploic artery (GEA) is commonly used in coronary artery bypass grafting, but a method for preoperative assessment of the suitability of the GEA has not been established. Here, we assessed the efficacy of 64-slice multidetector computed tomography (MDCT) for this purpose.

METHODS

Multidetector computed tomography was performed for 32 patients (24 males, 8 females; mean age, 65.9 +/- 7.4 years) undergoing coronary artery bypass graft surgery. Preoperative MDCT criteria for GEA suitability were no significant stenosis or calcification and a diameter of 2.0 mm or more in the middle portion of the GEA. The skeletonized GEA was inspected in 30 patients to determine the accuracy of evaluation of arteriosclerosis by MDCT (2 patients were excluded owing to severe GEA stenosis). The internal diameter at the anastomotic site was compared with the diameters of the proximal, distal, and middle regions of the GEA on MDCT.

RESULTS

The GEA was used to bypass a target coronary artery in 30 patients. The diameter of the middle of the GEA on MDCT correlated strongly with the actual internal diameter at the anastomotic site (r = 0.72, p < 0.0001). The diameter at the anastomotic site calculated from MDCT using the distance from the GEA origin to the anastomotic site and the actual diameter did not differ significantly (2.76 +/- 0.6 versus 2.87 +/- 0.5 mm, p = 0.06).

CONCLUSIONS

Preoperative MDCT imaging of the GEA is reliable for diagnosis, and a middle diameter of 2.0 mm or greater can be used to indicate GEA suitability for coronary artery bypass grafting.

The right gastroepiploic artery in coronary artery bypass grafting

The right gastroepiploic artery (RGEA) has been used as a conduit in coronary artery bypass grafting. Although some reports presenting good results justify its use in clinical settings, there is still much concern about using the RGEA in bypass surgery. The RGEA demonstrates different behaviors from the internal thoracic artery (ITA) in bypass surgery due to its histological characteristics and anatomical difference, which might contribute to the long-term outcome. Now that left ITA (LITA) to left anterior descending artery (LAD) is the gold standard, other grafts are expected to cover the rest of the coronary arteries. It should be elucidated how we can use other grafts and what we can expect from them. RGEA, as an arterial graft, can be used as an in situ graft or a free graft. The RGEA is mainly used to graft to the right coronary artery (RCA) because of its anatomical position, and its patency is not inferior to that of the saphenous vein (SVG). The RGEA can cover the lateral walls when its length is long enough or by making a composite graft with other grafts. However, when used to graft to the LAD, its mid-term patency is not favorable.

Configurations and classifications of composite arterial grafts in coronary bypass surgery

The aim of this review is to present the configurations and classifications of composite arterial grafts in coronary bypass surgery. Articles were collected by tracking references cited in the literature with regard to the configurations of composite arterial grafts in coronary bypass surgery. Figures of the configurations were drawn in accordance to the schematic drawings, angiograms, photographs, table contents or written captions of the literature. According to their structural nature, composite arterial grafts can be classified as: (i) alphabetical (Y, T, I, U, K, X and H) and (ii) complex grafts (TY, loop, pi and sling grafts). According to the conduits that form the composite graft, they can be classified as: (i) definite (all standard alphabetical grafts, classic pi and sling grafts); (ii) varying [internal mammary artery (IMA) loop, modified pi graft]; and (iii) indefinite conduit graft (TY graft). According to their application in coronary artery bypass grafting (CABG), they can be divided into complete arterial revascularization for: (i) triple vessel disease (T, Y, K, X, TY, pi and sling grafts); (ii) two vessel disease (U, right Y, and two-thirds right IMA T grafts); and (iii) single vessel disease, mainly the left anterior descending artery with or without the diagonal branch (H, I, IMA loop and left IMA T grafts). According to the CABG method, they can be classified as: (i) for conventional CABG (sling graft); (ii) for minimally invasive direct coronary artery bypass (H graft); and (iii) for both conventional CABG and off-pump coronary artery bypass (T, Y, U, K, I, TY, IMA loop, and pi grafts). Standard Y and T grafts have been accepted as the common figurations of composite arterial grafts to maximum graft length for the bypass of triple vessel disease. Composite arterial grafts overcome the limited availability of arterial conduits for performing total arterial myocardial revascularization, allow a gain in conduit length, and minimize the ascending aorta manipulation.

Twenty Years Experience With the Gastroepiploic Artery Graft for CABG

BACKGROUND

To improve the longterm outcome after CABG, several strategies have been used using arterial conduits. Our 20 years experience with the right gastroepiploic artery (GEA) graft was evaluated.

METHODS AND RESULTS

In 1352 patients having CABG with the GEA graft, (1092 men, mean 63 years, 99% multivessel disease, and mean EF 0.51), internal thoracic artery, saphenous vein, and radial artery grafts were concomitantly used in 1312 (97%), 783 (58%), and 128 (8%) patients, respectively. The mean number of distal anastomoses was 3.1, and 2.4 coronary arteries were bypassed with arterial grafts. The sites for GEA grafting were 70 anterior descending, 268 circumflex, and 1089 right coronary arteries. The operative mortality was 1.26%. In 1118 follow-up patients (82.6%), 5, 10, and 15 years survival rates were 91.7%, 81.4%, and 71.3%, and the cardiac death-free survival rates were 95.8%, 91.7%, and 88.6%, respectively. The cumulative patency rate of the GEA graft was 97.1% at 1 month, 92.3% at 1 year, 85.5% at 5 years, and 66.5% at 10 years, respectively. In 172 skeletonized GEA grafts with 233 distal anastomoses, the patency rate at immediate, 1, and 4 years after surgery was 97.6%, 92.9%, and 86.4%, respectively. In 124 patients with late (5 to 17 years) restudy, patency rate was 96% (114/119) in the left internal thoracic artery, 87% (108/124) in GEA, and 68% (67/98) in saphenous vein grafts. New stenosis was uncommon in GEA.

CONCLUSION

The GEA graft is a safe and effective arterial conduit for CABG.

Skeletonization of radial and gastroepiploic conduits in coronary artery bypass surgery

The use of a skeletonized internal thoracic artery in coronary artery bypass graft surgery has been shown to confer certain advantages over a traditional pedicled technique, particularly in certain patient groups. Recent reports indicate that radial and gastroepiploic arteries can also be harvested using a skeletonized technique. The aim of this study is to systematically review the available evidence regarding the use of skeletonized radial and gastroepiploic arteries within coronary artery bypass surgery, focusing specifically on it's effect on conduit length and flow, levels of endothelial damage, graft patency and clinical outcome. Four electronic databases were systematically searched for studies reporting the utilisation of the skeletonization technique within coronary revascularisation surgery in humans. Reference lists of all identified studies were checked for any missing publications. There appears to be some evidence that skeletonization may improve angiographic patency, when compared with pedicled vessels in the short to mid-term. We have found no suggestion of increased complication rates or increased operating time. Skeletonization may increase the length of the conduit, and the number of sequential graft sites, but no clear clinical benefits are apparent. Our study suggests that there is not enough high quality or consistent evidence to currently advocate the application of this technique to radial or gastroepiploic conduits ahead of a traditional pedicled technique.

Midterm Results for Use of the Skeletonized Gastroepiploic Artery Graft in Coronary Artery Bypass

BACKGROUND

To improve the long-term results of coronary artery bypass grafting (CABG), several arterial conduits have been used, including the skeletonized right gastroepiploic artery (GEA) graft.

METHODS AND RESULTS

The skeletonized GEA graft was used for CABG in 223 patients over a 6-year period (208 males, 15 females, mean age 64 years). 1-, 2- and 3-vessel and left main trunk disease was noted in 1, 28, 122 and 72 patients, respectively. Internal thoracic artery, radial artery and saphenous vein grafts were concomitantly used in 217 (97%), 73 (33%) and 41 (18%) patients, respectively, and the mean number of grafts was 3.5. The sites of GEA grafting were 1 anterior descending, 10 diagonal, 97 circumflex, and 185 right coronary arteries, with 154 single in-situ, 33 free and 36 composite grafts, including 56 sequential grafts. There was 1 (0.4%) operative death. New Q wave was noted in 2 (0.9%) patients. Postoperative angiography revealed 97.6% early postoperative (within 1 month) and 91.5% midterm (mean 27 months) patency rates for GEA grafts. The cumulative 4-year patency rate of the skeletonized GEA graft was 86.4%.

CONCLUSION

The skeletonized GEA is a safe and effective arterial conduit for CABG.