Poor long-term patency rates have been documented for saphenous vein grafts; only 50–60% of saphenous vein grafts are patent 10 years post-operation.1 On the other hand, excellent long-term patency of the left internal mammary artery for coronary revascularization has been demonstrated, which may explain improved long-term patient survival.2 Thus, the expanded use of arterial grafts and minimized use of vein grafts has been advocated. Various arterial grafts, such as the inferior epigastric artery, right gastroepiploic artery and radial artery, have been utilized to supplement the internal mammary artery to achieve complete arterial coronary revascularization.3–10 The radial artery graft is rapidly gaining popularity because of its length, diameter and encouraging mid-term results.3–10 As a free arterial graft, the proximal anastomosis of the radial artery graft may be located at various arteries, although the majority are anastomosed to the ascending aorta.3,5–8 Thus, percutaneous revascularization procedures may be performed in lesions located in radial arterial grafts with the proximal anastomosis site at a location other than the ascending aorta.11 In the present case, percutaneous coronary intervention was performed in a lesion located in a sequential radial artery graft anastomosed to the descending aorta, distal circumflex artery and obtuse marginal artery. Case Report. A 55-year-old male, status post-coronary bypass surgery with previous stent placements at the left main, left circumflex, obtuse marginal and left anterior descending coronary arteries, was admitted due to unstable angina. Coronary angiography demonstrated total occlusions of the left anterior descending and right coronary arteries. There were 90% in-stent restenoses in the left main, left circumflex, and obtuse marginal arteries. Total occlusion was observed in saphenous vein grafts to the right coronary and diagonal arteries. The left internal mammary artery to the left anterior descending coronary artery was patent. The patient was referred for minimally invasive coronary artery bypass grafting using a radial artery graft in a sequential fashion anastomosed to the descending aorta, distal left circumflex artery and obtuse marginal artery. The patient’s hospital course was uneventful and he had been free of angina. Two months later, the patient was readmitted due to unstable angina. Coronary angiography revealed development of 80% stenosis in the mid-segment of the free radial artery graft and 60% stenosis in the distal left circumflex artery distal to the anastomosis (Figure 1A). The patient had been given an intravenous infusion of nitroglycerin (200 µg/minute). A bolus of nitroglycerin (100 µg) was administered into the radial artery graft, but did not change the degree of the stenoses. Left ventriculogram demonstrated reduced systolic function with an ejection fraction of 35%. The patient was referred for coronary angioplasty for a lesion in the mid-segment of the radial artery graft. A 7 French AR2 guiding catheter (Cordis Corporation, Miami Lakes, Florida) was positioned at the ostium of the radial artery graft through the right femoral artery. A 0.014´´ Balance guidewire (Guidant Corporation, Temecula, California) was advanced into the distal radial artery graft. A 2.5 mm Adante balloon catheter (Boston Scientific/Scimed, Inc., Maple Grove, Minnesota) was passed through the lesion and multiple balloon inflations up to 12 atmospheres for a total of 320 seconds were performed (Figure 1B). Spasm of the radial artery graft was not observed during the procedure. The final angiogram demonstrated a good result (Figure 1C). The patient’s course after the procedure was uncomplicated. The patient remains free of angina 1 year after the procedure. Discussion. Introduced into clinical practice by Carpentier in the early 1970s,12 the radial artery graft was quickly abandoned because of a high incidence of graft failure secondary to spasm and traumatic harvest techniques.13 In 1989, Carpentier’s group reintroduced the radial artery graft for coronary artery bypass grafting because follow-up angiography of patients in whom the radial artery graft had been thought to be totally or partially occluded revealed patent, angiographically normal radial artery grafts.14 Technical modifications such as intraluminal dilation with papaverine and post-operative administration of calcium-channel blockers to limit graft spasm were adopted. Previous studies showed early patency rates of 86.9–100%.4,14,15 Encouraging 5-year radial artery graft patency rates of 83% and 87% were reported.9,10 Previous case reports11,16–18 demonstrated successful percutaneous coronary intervention in radial artery grafts. However, caution is advised when radial artery grafts are the target vessels for coronary intervention. Radial artery grafts are potentially spastic in nature and the procedure should be covered with the liberal use of vasorelaxant drugs.11,17 This complication was not observed in the present case (probably because an intravenous infusion of nitroglycerin was administered for frequent angina attacks).19 One may suspect that the early radial artery graft failure was caused by spasm. The balloon catheter is fully expanded at a low inflation pressure in lesions caused by spasm.20 In the present case, it was necessary to inflate the balloon catheter up to 12 atmospheres. Thus, the stenosis might be caused by arterial remodeling and/or progressive atherosclerosis that were associated with the interruption of vasovasorum and endothelial damage of the radial artery due to the surgery.16 Radial artery grafts, which are free and long in length, may be proximally anastomosed to various arteries; in most cases, the proximal anastomosis sites are the ascending aorta. Some surgeons may prefer to perform a composite arterial graft with the radial artery coming off the left mammary artery.3 In some selected cases, the radial artery can also be proximally anastomosed to a saphenous vein graft,5 to the right internal mammary artery,5 to another radial artery graft,6 to the innominate artery7 or to another coronary artery8 (a coronary-to-coronary bypass graft). Recently, minimally invasive coronary bypass grafting using the radial artery graft anastomosed to the descending aorta and left circumflex artery has been reported as redo coronary artery bypass graft surgery, especially when there is a patent internal mammary graft to the left anterior descending coronary artery.21 Thus, coronary interventionalists may encounter cases where the proximal anastomosis of the radial artery graft is not located at the ascending aorta.11 Percutaneous coronary intervention through the radial artery graft anastomosed to the descending aorta may be performed using the techniques that are used for coronary intervention in native coronary arteries and other grafts.11 An Amplatz guiding catheter may be appropriate to engage the ostium at the descending aorta through the femoral artery. In the present case, the radial artery graft was a very tortuous sequential graft. Thus, a floppy guidewire (Balance) and a low-profile balloon (Adante) were selected. Although there were no complications in this case, percutaneous cardiopulmonary support should be available when percutaneous coronary intervention is performed in such cases, because intraaortic balloon pump is not feasible due to the origin of the radial graft from the descending aorta.11 This case report demonstrates percutaneous coronary intervention in a sequential radial artery graft anastomosed to the descending aorta, left circumflex artery and obtuse marginal artery. With the increasing use of the radial artery in coronary artery bypass surgery, coronary interventionalists may encounter cases with a lesion in a radial artery graft with the proximal anastomosis site at a location other than the ascending aorta.
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