Case Presentation. A 58-year-old male presented with substernal chest pain that started while mowing his lawn. The chest pain radiated to the left shoulder and was not relieved with sublingual nitroglycerin. He had controlled hypertension and type II diabetes mellitus. He had undergone percutaneous intervention with bare-metal stenting of the ostial circumflex (CFX) and ostial left anterior descending (LAD) arteries. The patient developed in-stent restenosis of his CFX and LAD stents. He underwent coronary artery bypass surgery (CABG), involving placement of a left internal mammary artery (LIMA) graft to the left anterior descending (LAD) artery, and a Y radial artery graft to the second obtuse marginal artery. He also underwent dual-chamber pacemaker implantation for symptomatic sinus bradycardia. A persantine sestamibi stress test performed during this hospitalization revealed a reversible anterolateral defect (Figure 1).

Coronary angiography showed 30% stenosis in the distal left main artery, 80% in-stent restenosis in the ostial CFX, and 60% in-stent restenosis of the ostial LAD. The tortuous LIMA graft to the LAD and the radial graft to the obtuse marginal branch were free of atherosclerotic disease, but a transient occlusion of the LIMA in mid-segment was observed during the expiratory phase of respiration (Figures 2 A and B). The patient’s symptoms and the reversible anterolateral defect observed on the functional study were felt to be secondary to the transient occlusion of the LIMA graft that occurred with expiration. He underwent stenting of the left main, ostial LAD and CFX coronary arteries, with relief of symptoms.

Discussion. This case illustrates that kinking of bypass grafts during the expiratory phase should be considered in the differential diagnosis of chest pain in patients who have undergone CABG. Ischemia due to kinking has been reported to occur as a rare phenomenon with both LIMA and saphenous vein grafts.^1,2 Percutaneous and surgical intervention has been attempted to relieve occlusion due to kinking in such cases.^2,3 Our patient showed marked symptomatic relief after placement of a stent in the native coronary circulation.