Surgery can in- clude reimplantation of the right coronary artery directly into the aorta with or without an interpo- sition graft. Ligation or closure of the right cor- onary artery at the level of the PA with coronary artery bypass grafting can also be performed, usually using the right internal mammary artery anastomosed to the right coronary or posterior descending coronary artery. 4.4.8. Coronary Artery Fistula Coronary artery fistula is an abnormal communication between a coronary artery and another cardiovascular Table 35. High-Impact Research Questions in ACHD General Pathophysiology What are the mechanisms of heart failure that can be prevented, reversed, or treated? Why does the systemic right ventricle fail? Will all patients with Fontan physiology develop clinically important cirrhosis, and how can we prevent this? Who is at risk of aortic rupture and dilation? Are patients with manipulated coronary arteries (eg, ASO, Ross repair) at risk of premature coronary artery disease? What is the impact of radiation exposure on long-term health? Can we predict who will develop pulmonary hypertension/pulmonary vascular disease? Medical and surgical treatment How can we modify current CHD surgical procedures to prevent or reduce later development of heart failure and/or arrhythmias? Which patients with ACHD can use direct oral anticoagulants instead of warfarin? What is the best algorithm for contraception choices? Beyond those with severe PAH, which patients will benefit from PAH therapies? Do patients with ACHD with systemic right ventricles and HF benefit from standard therapies (beta blockers, ACE inhibitors/ARBs, aldosterone antagonist)? Which one(s)? What medical therapies benefit patients with failing Fontan physiology? Do asymptomatic patients with ACHD with PAH benefit from PAH-specific therapy? Who will benefit from ventricular assist devices? What should be the threshold(s) for aortic aneurysm surgery? What pacing and resynchronization strategies are of most benefit, and when should they be used? 