Anastomotic Graft Markers in PVD
This simple technique is good for the interventionalist and the endovascular surgeon, but most of all it is good for the patient.
To view the tables related to this article, please refer to the print version of our July/August issue, page 27.
Proximal aortocoronary anastomotic graft markers (AGM) were described more than 30 years ago but are still utilized in only 60.5% of all CABGs performed annually in the US and in <50% performed worldwide.1,2 The Society of Thoracic Surgery has never published a definitive position paper recommending AGM use in all cases because of what most cardiothoracic surgeons perceive as a “lack of benefit”;1,3 despite several reports objectively identifying and quantifying the following clinical and economic benefits to the angiographer, interventionalist, hospital lab staff, surgeon, hospital, and patient:4,5
• 30% reduction in radiation exposure corresponding to an equivalent radiation dose equal to 1,500 PA chest x-rays;
• 22% reduction in contrast volume;
• 17% reduction in number of angiographic catheters used per case;
• 8.6-minute decrease in fluoroscopic time with a significant reduction in overall procedural time, catheter exchanges, and manipulations.
These factors should result in a direct reduction in procedural risk for the patient and hospital cost savings during subsequent angiography or intervention if AGMs are used during CABG. Additionally, no perioperative or postoperative complications directly related to an AGM insertion have ever been reported. Vascular surgeons are not traditionally exposed to AGMs in their training; therefore use of AGMs in peripheral vascular surgical procedures is rare and has not been reported in the PVD literature. The potential clinical benefits of AGMs are summarized in Table 1.
Several types of AGMs have been described during CABG, each with proposed advantages and perceived disadvantages.1,4,6 Circumferential metallic or opaque nonmetallic AGMs appear to offer graft intubation advantages after CABG; however, concerns by surgeons include increased operative time and difficult placement in a crowded aorta, and an increased risk of graft kinking, aortic scarring, infection, and decreased graft patency. None of these concerns has ever been proven in a scientific evidenced-based report, and Eisenhauer et al5 reported an increased patency rate in marked versus unmarked vein grafts after CABG (71.1% versus 50% patency rate at 5 years), suggesting that AGM may have a positive effect on patency rates.
Our AGM of choice is the 0.108-mm-diameter metallic Precision Washer (PIC Design, Middleburg, CT), which is low-profile yet opaque, simple to use, and effectively kink resistant. The Washer AGM is secured at the anastomosis after the last throw of the anastomotic suture by passing the uncut needle through the center of the washer and making three more suture throws before cutting the suture securing the AGM at the anastomosis (Figure 1A). Leaving one needle uncut during tying will facilitate AGM placement (Figure 1B). We recommend placing the AGM at the 12-o’clock position for a femoral bypass graft (FBG) proximal anastomosis (Figure 2A) and at the 6-o’clock position for the distal anastomosis (Figure 2A). We now recommend AGM on all surgical bypass anastomoses (including composite) and the proximal and distal limits of all surgical patch angioplasty procedures (including carotid).
AGM USE IN ACUTE LIMB ISCHEMIA
Because a greater number of PVD patients are treated interventionally, AGM can play an important clinical role, especially in the treatment of infrainguinal PVD and acute limb ischemia (ALI). Reports have shown improved outcomes with an interventional first approach in ALI.6 Many of these patients present with an acutely thrombosed bypass graft, oftentimes arriving as an emergency with incomplete records and information regarding their surgical history. Thrombosed FBGs can be salvaged with interventional techniques but the initial imaging of these thrombosed grafts can be troublesome. Fluoroscopic identification of previously placed AGM could potentially facilitate and improve the clinical care and overall outcomes of this patient population.
An FBG or prosthetic patch can originate at different angles and multiple sites from the femoral artery (Figure 3A,B); therefore, an AGM could greatly facilitate FBG intubation, angiography, and intervention with less time, catheter manipulations, trauma, radiation exposure, and contrast use. These benefits are especially important to patients with PVD because they have a higher incidence of diabetes and renal insufficiency than the coronary patient and oftentimes must undergo complex PVD procedures require long procedural times, catheter exchanges, and higher contrast volume.7 AGM identification could give clinical information relating to the exact transition between surgical prosthetic material and native vascular endothelium, which may have clinical implications. Examples would include balloon angioplasty inflation pressures, PTA with or without stenting across an anastomosis, and the exact placement of lytic or thrombectomy catheters.
AMG IN FBG SURVEILLANCE
Elective tibial and femoral bypass grafts have excellent 3-year, 5-year, and even 10-year primary assisted patency rates, but 30% to 40% will require postoperative angiography and a secondary intervention.8,9 Ultrasound FBG surveillance studies have indicated that 26% of grafts will need a secondary procedure to facilitate long-term patency.10,11 AGMs could facilitate these elective secondary interventions, which will include angiography and oftentimes a percutaneous intervention. With the emergence of carotid stenting, we now recommend an AGM on the distal and proximal limits of the carotid patch because exact identification of these sites may also carry clinical implications and affect treatment strategy.
As the vascular surgeon develops catheter-based skills and techniques, increasingly performs angiography, and develops closer relationships with the interventionalist, the clinical benefits of AGM use during open vascular surgical procedures for PVD will become increasingly apparent. We believe AGM use in the endovascular surgical treatment of PVD is equally, if not more, important than AGM use during CABG.
David E. Allie, MD, is Director of Cardiothoracic and Endovascular Surgery at the Cardiovascular Institute of the South in Lafayette, Louisiana. He holds no financial interest in any product or manufacturer mentioned herein. Dr. Allie may be reached at (800) 582-2435; David.Allie@cardio.com.
Chris J. Hebert, RT, RCIS, is Director of Technology at the Cardiovascular Institute of the South in Lafayette, Louisiana. He holds no financial interest in any product or manufacturer mentioned herein. Mr. Hebert may be reached at (800) 582-2435; Chris.Hebert@cardio.com.
Mohamed H. Khan, MD, is Medical Director of the Cardiovascular Institute of the South in Opelousas, Louisiana. He holds no financial interest in any product or manufacturer mentioned herein. Dr. Khan may be reached at (800) 553-2394; Mohamed.Khan@cardio.com.
Craig M. Walker, MD, is Medical Director of the Cardio-vascular Institute of the South in Houma, Louisiana. He holds no financial interest in any product or manufacturer mentioned herein. Dr. Walker may be reached at (800) 445-9676; Craig.Walker@cardio.com.
1. Eisenhauer MD, Wicks AB, Olson JP, et al. Prevalence of aortocoronary graft marker use and the factors affecting this decision. J Card Surg. 1998;13:194-199.
2. Peterson LR, McKenzie CR, Ludbrook PA, et al. Value of saphenous vein graft markers during subsequent diagnostic cardiac catheterization. Ann Thorac Surg. 1999;68:2263-2266.
3. Practice guidelines in cardiothoracic surgery. Ad Hoc Committee for Cardiothoracic Surgical Practice Guidelines. Ann Thorac Surg. 1995;60(Suppl):S1-S59.
4. Eisenhauer MD, Malik JA, Coyle LC, et al. Impact of aorto-coronary graft markers on subsequent graft patency: a retrospective review. Cathet Cardiovasc Diagn. 1997;42:259-261.
5. Eisenhauer MD, Collier HE, Eisenhauer TL, et al. Beneficial impact of aorto-coronary graft markers on post-operative angiography. Cathet Cardiovasc Diagn. 1997;40:249-253.
6. Halseth WL, Elliot EL, Walker EL, et al. Angiographic restudy of coronary artery bypass grafts simplified by a marker. Clin Radiol. 1978;1:169-172.
7. Allie DE, Lirtzman MD, Walker CM, et al. Bivalirudin as a foundation anticoagulant in peripheral vascular disease: a safe and feasible alternative to renal and iliac interventions. J Invas Cardiol. 2003;15:334-342.
8. Pomposelli FB, Kansal N, Hamdan AD, et al. A decade of experience with dorsalis pedis artery bypass: analysis of outcome in more than 1000 cases. J Vasc Surg. 2003;37:307-314.
9. Landry ZGJ, Moneta GL, Taylor LM, et al. Long-term outcome of revised lower-extremity bypass grafts. J Vasc Surg. 2002;35:56-63.
10. Bandyk DF, Shmitt DD, Seabrook GR, et al. Monitoring functional patency of in situ saphenous vein bypasses: the impact of a surveillance protocol and elective revision. J Vasc Surg. 1989;9:286-96.
11. Ferris BL, Mills JL, Hughes JD, et al. Is early postoperative duplex scan surveillance of leg bypass grafts clinically important? J Vasc Surg. 2003;37:495-500.
Figure 1. A metallic AGM adjacent to a 4-mm-diameter composite vein bypass anastomosis (top). Needle and suture being passed through the center of an AGM during ePTFE bypass (middle). Example of a metallic AGM after PTA/stent deployment at a composite vein bypass postoperative anastomotic stricture (bottom).
Figure 2. A metallic AGM at the 12-o’clock position (proximal anastomosis) during femoral-tibial bypass. Note the anterior position of the AGM to facilitate graft intubation (top). An AGM at the 6-o’clock position (distal anastomosis) during femoral-peroneal bypass. Note that the distal AGM position marks the transition to native vessel (bpttom).
Figure 3. Fluoroscopic magnification of a complex postoperative left CFA. Note the multiple random surgical staples and the precision washer AGM marking the proximal and distal limits of a prosthetic patch angioplasty (top). AGM assists identification and localization of a distal patch stricture, potentially affecting clinical decision making (bottom).