• Arterial Access via a Bypass Graft

    December 12, 2018

    Mazen Abu-Fadel MD, FSCAI, and Joaquin Cigarroa MD, FSCAI

    Femoral arterial access via a synthetic bypass graft for coronary/peripheral endovascular procedures is infrequent in this era due to advancements in accessing the radial/ulnar arteries as well as accessing the popliteal and tibial arteries for peripheral interventions. However, for interventionalists who perform peripheral arterial angiography and interventions in patients with severe peripheral arterial disease, angiography via aorto-bifemoral bypass grafts may be required. Other specific clinical scenarios that may necessitate accessing a bypass graft include patients with bilateral subclavian stenosis or occlusion and patients on hemodialysis who have an arteriovenous (AV) fistula. Aorto-femoral graft access site complications have been reported to be as high as 12 percent (4 percent major). However, most published data comes from a small case series and older retrospective data.1–4 Tips and tricks for obtaining vascular access through an arterial bypass graft are presented below.

    1. First and most important, avoid access through a bypass graft, if at all possible. With contemporary techniques of radial and ulnar access, only a small number of patients will require access through a bypass graft.

    2. Employ all efforts to review the surgical operative report to understand the arterial anatomy and bypass anatomy prior to accessing the bypass graft. Furthermore, assess distal pulses by palpation and Doppler and assess distal perfusion of the feet. Patients with poor distal runoff may be at increased risk of periprocedural graft thrombosis.

    3. Use a combination of fluoroscopy and ultrasound guidance to access the graft in the middle of the femoral head. Avoid the anastomosis site, as it is a frequent site of aneurysmal dilatation — which may result in the strongest palpable pulse and lead inexperienced operators to inappropriately access at the site of anastomosis.

    4. Use a micropuncture needle, preferably with an echogenic tip (for ultrasound visualization), to obtain access and avoid through-and-through access in the graft. Unlike the femoral artery, the graft will not recoil in case of inadvertent posterior wall puncture. The use of ultrasound will decrease the number of access attempts and allow one to avoid calcified segments and posterior wall puncture. It is important to be aware that there may be residual pulsatile flow in the original vessel lumen posterior to the graft, but cephalad advancement of the guidewire will be impossible due to upstream native vessel occlusion.

    5. After access is obtained, dilate the tract serially starting with a dilator smaller than the sheath size and proceed to a dilator equal to or one French size larger than the size of the sheath to be used. Unlike the femoral artery, the graft wall is stiffer with associated scar tissue in the femoral area due to previous surgery. An extra-stiff wire should be used to provide support for the passage of dilators and the sheath.

    6. Use the smallest-sized sheath possible to complete the procedure. When appropriate, consider the use of a hydrophilic radial sheath with a smaller outer diameter, such as the Slender Sheath or the Prelude IDEAL sheath (Merit Medical, South Jordan, UT), which has a reinforced wall that is more kink resistant. To overcome sheath kinking, a 0.035” wire should be maintained across the sheath when performing catheter exchanges.

    7. Change the dilator that comes with the sheath to another dilator that can accommodate a 0.035” wire, instead of using the smaller diameter wire that comes with the thin-walled sheath. This will allow the necessary wire support, as mentioned above in #5.

    8. After the sheath is inserted, perform a routine femoral angiogram to understand the anatomy and to assess the runoff vessels beyond the bypass graft. Knowledge of the baseline anatomy will prove helpful in case a post-procedure complication occurs.

    9. Note that the utility of routine anticoagulation to lower the risk of graft thrombosis is unknown.

    10. After the procedure is over, have an experienced operator remove the sheath as soon as possible by utilizing a patent hemostasis technique (ensuring that a distal pulse is palpable while holding pressure). If anticoagulation is given, then follow the hospital policy on sheath removal to determine when the sheath can be removed. Again, the priority should be to limit sheath dwell time.

    11. Although there are case reports regarding the use of vascular closure devices with bypass grafts, do not use vascular closures devices, FemoStop devices, and C-clamps. Instead, utilize manual hemostasis employing a patent hemostasis technique, as mentioned above. A femoro-femoral bypass graft is especially susceptible to thrombotic occlusion with excessive and prolonged manual compression. Distal pulses must be monitored and documented pre- and post-sheath removal.

    12. During bypass graft access and sheath removal, pay meticulous attention to a sterile technique. The role of routine antibiotics is not clear, but their use should be considered. The patient should be instructed to immediately seek medical attention in the event of persistent pain, discharge, or pus from the access site. If that is noted, it should raise an immediate concern for graft infection, which requires prompt consultation with a vascular surgeon.

     

    Conclusion

    Aorto-femoral bypass grafts should be accessed only in the absence of alternate vascular access. Meticulous attention to pre-procedure assessment, an aseptic technique, and sheath insertion and removal should be undertaken to minimize complications.

     

    References

    1. Michael GJ, Simon DR, Robert SD, et. al. Safety of Percutaneous Transfemoral Coronary and Peripheral Procedures Via Aortofemoral Synthetic Vascular Grafts. Am J Cardiol, 2005; 96(3):382-385.
    2. Abu Rahma AF, Robinson PA, Boland JP. Safety of arteriography by direct puncture of a vascular prosthesis. Am J Surg 1992; 164:233-236.
    3. Lesnefsky EJ, Carrea FP, Groves BM. Safety of cardiac catheterization via peripheral vascular grafts. Cathet Cardiovasc Diagn. 1993 Jun; 29(2):113-6.
    4. Da Silva, JR, Marlene ER, Vasilios K, et. al. Aortofemoral bypass grafts: Safety of percutaneous puncture. Journal of Vascular Surgery. 1984; 1(5):642-645.