Bypass to the Distal Right Coronary Artery Using In Situ Gastroepiploic Artery*

Refinement of Coronary Artery Bypass Grafting at Juntendo University Hospital

Surgical treatment of ischemic heart disease began in 1945. After 1970, coronary artery bypass grafting (CABG) with cardiopulmonary bypass was developed along with coronary angiography. Juntendo University has been treating ischemic heart disease since 1980, and is actively performing off-pump CABG (OPCAB) since 2002. Besides the age of patients undergoing surgery, complications such as chronic hemodialysis, cerebrovascular disease, and malignancies make it challenging to reduce postoperative complications using OPCAB as graft preservation. OPCAB is technically challenging, and the CORONARY trial did not reveal its superiority over conventional CABG. Furthermore, high revascularization rates and technical differences among surgeons are important concerns. While not widely accepted in Europe and the United States, OPCAB comprises 65% of all stand-alone CABG in Japan. Japan reported a 2.5% hospital mortality rate in 2018, while the US reported 2.2% (according to the American Association of Thoracic Surgeons). In contrast, Juntendo University Hospital has maintained a 1% hospital mortality rate since 1984. To reduce the incidence of remote stroke in CABG patients, Juntendo has been using stroke-free management since 2010. Postoperative atrial fibrillation is 4-5 times more likely to recur than normal sinus rhythm after a 5-year course. In our study, 20% of patients suffered from chronic atrial fibrillation after ten years. Furthermore, left atrial appendage closure or amputation significantly reduces stroke in patients who undergo CABG and develop postoperative atrial fibrillation. Thus, OPCAB is a minimally invasive procedure with fewer complications; prevention of cardiogenic cerebral infarction can help improve remote outcomes.

How does the right gastroepiploic artery compare with the saphenous vein for revascularization of the right coronary artery?

A best evidence topic was written according to a structured protocol. The question addressed was 'is the saphenous vein graft or right gastroepiploic artery a better conduit for revascularization of the right coronary artery?' One hundred and five articles were found using a designated search, of which 10 articles were found to represent the best available evidence to answer the clinical question. Of these 10 articles, two were reports of a randomized controlled trial and represented the highest level of evidence, whereas eight articles were retrospective observational studies. All were published between 2002 and 2012. Outcome measures varied considerably, but mostly included graft patency at varying periods of follow-up. The randomized evidence suggested that the saphenous vein had better early (6-month) and mid-term (3-year) graft patency than the right gastroepiploic artery when used for right coronary artery revascularization. The use of the saphenous vein was also found to be predictive of superior graft function using multivariate regression; however, a more recent propensity score analysis identified gastroepiploic-right coronary grafts to yield superior very long-term (>10 years) clinical outcomes. Overall, based on the best quality evidence and in view of technical limitations and flow characteristics of the right gastroepiploic artery, it appears that saphenous vein grafts may offer superior outcomes for revascularization of the right coronary artery in most cases, and should be preferentially used.

Off-pump coronary artery bypass grafting as re-do surgery in two cases in which the right gastroepiploic artery was grafted to the right coronary artery

Transdiaphragmatic off-pump coronary artery bypass grafting (OPCAB) to the right coronary artery, is an effective way to reduce the risks of second bypass surgery as well as the risk of graft injury after coronary artery bypass grafting (CABG). We report two cases of successful OPCAB as re-do surgery in which the right gastroepiploic artery (RGEA) was grafted to the right coronary artery. The first case was a 58-year-old woman, who underwent CABG 10 years ago. OPCAB (RGEA to right coronary artery) was performed since myocardial perfusion scintigraphy revealed ischemia in the inferior wall. The second case was a 67-year-old man who had hypertension, hyperlipidemia, peripheral arterial disease, and was undergoing dialysis (for 6 years). Six years previously, he developed a mycotic aneurysm of the right coronary artery and underwent open-heart surgery. He often had episodes of angina at night or during dialysis, and then developed congestive heart failure and was hospitalized. Since ischemia was considered to be in the inferior wall, the RGEA was grafted to the right coronary artery.

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.

Gastroepiploic Artery Grafting Does Not Improve the Late Outcome in Patients With Bilateral Internal Thoracic Artery Grafting

BACKGROUND

Bilateral internal thoracic artery grafting in coronary artery bypass surgery has a better long-term outcome than single internal thoracic artery grafting. However, the efficacy of gastroepiploic artery (GEA) grafting in addition to bilateral internal thoracic artery grafting is still not well-established.

METHODS

From 1989 to 1999, 311 patients underwent coronary artery bypass grafting using in situ bilateral internal thoracic arteries anastomosed to the left coronary arteries and either an in situ GEA or a saphenous vein graft (SVG) anastomosed to the right coronary artery. Ninety-nine patients using the in situ GEA (GEA group) were compared with 212 patients using the SVG (SVG group) anastomsed to the right coronary artery. Young patients and patients with hyperlipidemia were more prevalent in the GEA group.

RESULTS

The seven-year survival rate in the GEA group and the SVG group were 94.7% and 87.2%, respectively (p = 0.068). In a multivariate analysis, the age, renal failure, and a low ejection fraction (<0.40) were all significant predictors of survival. The GEA was not a significant predictor. The seven-year freedom rates from cardiac events were similar in both groups (GEA group, 76.5%; SVG group, 78.6%; p = 0.455). The seven-year freedom rates from recurrent angina were also similar between the groups (GEA group, 85.3%; SVG group, 88.8%; p = 0.700).

CONCLUSIONS

In comparison with SVG grafting, GEA grafting to the right coronary artery did not significantly improve the late outcomes in patients with bilateral internal thoracic artery grafting.