Treatment of distal anastomotic lesions


 * Associate Editors-In-Chief: David M. Leder, M.D., Brian C. Bigelow, M.D.

Overview
Anastomotic lesions occur where a saphenous vein graft or internal mammary artery is attached to the native coronary vessel and these lesions are the result of fibrosis and intimal hyperplasia, as opposed to thrombus burden as seen in the body of saphenous vein grafts.

The Diameter of the Saphenous Vein Graft May Be Larger Than the Native Vessel
In the setting of a size mismatch, it is most appropriate to match the stent size to the native vessel, and flare the proximal part of the stent that lies within the saphenous vein graft.

Tortuosity of Internal Mammary Artery Grafts
Stiffer wires may be required to straighten the proximal segment of the internal mammary artery so that the anastomotic lesion can be reached by balloons and stents. To effectively reach distal lesions, shorter guiding catheters or PTCA balloon catheters with long shafts may be reqired. Additionally, small catheters with side holes should be chosen for IMA PCI to avoid catheter damping, vasospasm, and injury to the IMA ostium. Soft guidewires and/or hydrophilic wires for PCI of tortuous IMAs should be considered, as this helps avoid pleating and allows for the delivery of equipment.

Difficulty Delivering Devices Due to Distal Location
In order to allow balloons to reach anastomotic site, a short 100 cm guiding catheter may be required.

Extreme Agulation of the Lesion
Stiffer wires may be required to straighten angulated segments so that both balloons and stents can be advanced.

Balloon angioplasty (PTCA)
PTCA is the simplest approach for treating distal anastomotic lesions, and it also has the greatest chance of overcoming the limitations listed above.

Stenting
Stenting distal anastomotic lesions, particularly with drug eluting stents, reduces the risk of restenosis. However, proper placement and sizing of the stent may be challenging, due to differences in the diameter of the graft and the native vessel. Furthermore, stenting across the anastomotic lesion may limit retrograde access of the native vessel proximal to the anastomosis.

Rotational Atherectomy
Rotational atherectomy may facilitate balloon expansion, but it may also be difficult to deliver in tortuous IMA grafts. Additionally, it is important to note that rotational atherectomy is contraindicated in thrombotic or degenerated vein grafts.

Transluminal Extraction Catheter (TEC)
TEC is rarely used for anastomotic lesions because anastomotic lesions are not usually thrombotic or diffusely degenerated. When compared with PTCA and stenting, transluminal extraction catheters are associated with increased difficulty in delivering the device, as well as higher risks of dissection and possibly distal embolization.

Excimer Laser Coronary Angioplasty (ELCA)
ELCA is associated with a high initial success rate for the treatment of distal anastomotic lesions, but it also has a high rate of restenosis.

Complications
Although rare, rupture of distal anastomotic lesion can occur, particularly if the CABG was recently performed. Management is similar to that of vessel perforation.