片側および両側内胸動脈グラフトの成績は良好である

ART：片側および両側内胸動脈グラフトの主要な臨床上のイベントに差はない
ART: Trial of single and bilateral mammary artery grafts shows no difference in major clinical events
動脈血行再建術トライアル（Arterial Revascularization Trial：ART）の1年間の安全性データから、片側内胸動脈（SIMA）および両側内胸動脈（BIMA）はバイパス術を必要とする患者のほとんどにおいて施行可能であることが示された。これまでに行われた心臓手術トライアルでは最大規模のトライアルの1つであるARTは、BIMAグラフトとSIMAグラフトを比較した無作為化トライアルであり、一次アウトカムは10年生存率であった。二次エンドポイントには臨床イベント、QOLおよび費用対効果が含まれた。7ヵ国28施設の患者3,100人余りがSIMAまたはBIMAを受ける群に無作為に割り付けられた（両群ともに静脈グラフトで補足された）。その結果、両群ともに30日間の総死亡率は1.2%であり、1年間のそれは2.4%であった。従ってこの結果から、両側の内胸動脈を使用することはほとんどの患者において可能であり早期死亡率、脳卒中、心筋梗塞または入院期間を増加させないことが示された。しかし、両側内胸動脈バイパス術により胸骨創部再建手術のリスクは軽度（1.3%）増加した。このスタディの結果は2010年European Society of Cardiology学会のホットラインセッションで発表された。
Full Text

One year safety data from the Arterial Revascularization Trial (ART) show that both single internal mammary artery (SIMA) and bilateral internal mammary arteries (BIMA) grafts are feasible in most patients requiring bypass graft surgery. The study was reported during a Hotline session at the European Society of Cardiology Congress 2010.

Recent trial data indicate that coronary artery bypass graft (CABG) surgery remains the most effective intervention for patients with severe coronary artery disease (CAD). Moreover, for over two decades it has been recognized that the use of a single internal mammary artery (SIMA) during CABG improves survival and freedom from myocardial infarction, recurrent angina and repeat intervention. While most patients need three or four bypass grafts, revascularization can usually be effectively achieved with a combination of SIMA and supplementary vein grafts. However, while internal mammary arteries tend to remain patent almost indefinitely, there is a constant attrition of vein grafts such that by ten years after the operation half of the vein grafts are occluded and half of the remainder are severely diseased; by contrast more than 90% of the internal mammary arteries are still patent.

Observational data have also suggested that use of bilateral internal mammary arteries (BIMA) may provide superior revascularization with improved long-term survival and reduced need for repeat CABG. However, studies indicate that few patients having CABG in Europe and the USA actually receive BIMA because of concerns that it is technically more challenging and may increase early mortality and major morbidity.

The Arterial Revascularization Trial (ART), one of the largest trials ever conducted in cardiac surgery, was a randomized trial of BIMA grafts versus SIMA grafts whose primary outcome was survival at 10 years. Secondary end-points included clinical events, quality of life and cost effectiveness. Results reported at the ESC Congress are on safety data in the whole cohort up to one year after randomization.

"We felt that a trial was necessary because fewer than 10% of patients in Europe - and fewer than 5% in the United States - currently receive two internal mammary arteries," said principal investigator David Taggart, Professor of Cardiovascular Surgery at the John Radcliffe Hospital, Oxford, UK, "mainly because of a perception that the use of bilateral artery grafts increases the early mortality and major morbidity of the operation."

The ART trial enrolled more than 3100 patients (mean age 64 years) in 28 hospitals in seven countries, who were randomized to receive SIMA or BIMA (both with supplementary venous grafts). According to Professor Taggart, results showed that the one year outcome "is a testament to the remarkable safety of coronary artery bypass grafting", with an overall mortality rate of 1.2% at 30 days (in each group) and 2.4% at one year.

Results therefore showed that the use of two internal mammary arteries is indeed feasible in most patients and does not increase early mortality, stroke, myocardial infarction or duration of hospital stay. It did, however, lead to a small (1.3%) increase in the risk of sternal wound reconstruction.

ART is an investigator-initiated trial funded by the UK Medical Research Council and British Heart Foundation, and the first to compare SIMA and BIMA in a large-scale randomized trial.