Clinical Images
Saphenous Vein Graft Rheology Simulating a Thrombotic Lesion
February 2006
Case Presentation. A 59-year-old male was admitted for accelerated angina. Serial ECGs and cardiac enzymes ruled out a myocardial infarction. He had undergone coronary artery bypass grafting 4 years before, as well as coronary stenting of an ostial circumflex lesion 1 year after his bypass. After the procedure, he was doing well until his most recent presentation to us. Diagnostic coronary angiography documented severe native coronary artery disease with in-stent restenosis of the previously stented circumflex artery. A focal lesion was noted at the ostium of the large first septal perforator (Figure 1). Both the left internal mammary artery and saphenous vein grafts to the left anterior descending and right coronary arteries were widely patent. Oscillating flow with suggestion of a filling defect were noticed on angiography of the saphenous vein graft to the obtuse marginal branch (Figure 2, Movie 1*). Because of concern that this might represent a thrombus within the vein graft, intravascular ultrasound (IVUS) was performed to better define this filling defect. No thrombotic lesion was observed at the site of abnormality, and saline injection documented an unusual flow pattern (Figure 3, Movie 2). Following IVUS, repeat angiography document persistence of this abnormality. It was determined that the filling defect was consequent to abnormal flow in the vein graft and not a true lesion. The patient underwent percutaneous intervention of the septal perforator without complications and had complete resolution of his symptoms.
Flow within the saphenous vein graft is frequently nonphysiological and can be influenced by a variety of factors, including the diameter of the outflow into the native coronary artery. This alteration in flow profile can result in flow counter to the main lesion in contrast to a true thrombotic lesion. IVUS study with agitated saline is helpful when a firm diagnosis cannot be made on angiography.
*Movies are available with the online version of this article at www.invasivecardiology.com
