The Sheath-Through-Graft Technique
This hybrid endovascular surgical technique utilizes a PTFE bypass graft for vascular access, facilitating simultaneous interventional procedures.
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As the patient population ages and more surgical and interventional procedures are performed, clinicians will increasingly be challenged with more complex clinical scenarios, oftentimes presenting as simultaneous critical diseases in multiple vascular beds. Adding to this dilemma, many of these patients will have limited vascular access, requiring creative revascularization strategies. Combinations of surgical and nonsurgical interventions have been described in both the treatment of coronary artery disease and peripheral vascular disease (PVD), but have gained little acceptance.1-4 As endovascular surgeons rapidly acquire catheter-based skills and stronger relationships develop between surgeons and interventionalists, creative, less-invasive revascularization options or combined hybrid PVD procedures must be developed to improve outcomes for patients with increasingly complex PVD clinical scenarios.
The sheath-through-graft (STG) technique is a hybrid PVD procedure developed for patients presenting with limited percutaneous vascular access due to severe iliofemoral disease or previous femoral grafts and require femoral surgical revascularization and could simultaneously benefit from a more proximal (iliac, aorta, renal, subclavian, mesenteric, vertebral, or carotid) or distal (popliteal or infrapopliteal) interventional procedure. Severe lower-extremity symptoms requiring surgical revascularization may also present with simultaneous symptomatic critical disease in other vascular beds, thus providing an opportunity for surgical revascularization of the common femoral artery (CFA) and/or superficial femoral artery (SFA), while providing simultaneous interventional revascularization options for a more proximal or distal vascular segment.
THE STG TECHNIQUE
The STG technique utilizes very standard surgical and interventional principles, techniques, devices, and technologies (Figure 2). The central concept is to use the bypass graft conduit as vascular access for a simultaneous peripheral intervention. Preoperative strategic planning is imperative. The sequence of performing the proximal or distal surgical anastomosis first depends on the vessel requiring interventional revascularization. In a CFA or SFA bypass procedure, the proximal anastomosis would be made first in those patients requiring more proximal interventions, and the distal anastomosis would be performed first in patients requiring distal interventions. This sequencing will facilitate the STG technique, which has been utilized at our center in iliac, aortic, carotid, and renal proximal revascularizations and several distal revascularizations, including infrapopliteal excimer laser-assisted PTA (Spectranetics, Colorado Springs, CO) for limb salvage.
A 68-year-old man with severe diffuse PVD with a history of two CABGs, two aortobifemoral bypass grafts (ABFG), bilateral carotid endarterectomies (CEA), a repeat left CEA, an ejection fraction of 10% to 15%, and a recent (1 month) PTCA/stent via a left groin approach, presented with a left hemispheric TIA and a cold left leg with rest pain, which required analgesics. A diagnostic angiogram (left brachial approach) revealed a critical (>95%) left common carotid artery (CCA) stenosis at the presumed previous CEA proximal clamp site (Figure 1A) and 100% occlusion of the left CFA at the previous ABFG anastomotic site and probable recent PTCA stick site (Figure 1B). A creative, minimally invasive revascularization option simultaneously addressing both the left CFA and CCA seemed attractive in this patient with limited vascular access who was at high risk for cardiopulmonary mortality and morbidity during general anesthesia and second repeat CEA. If revascularization could not be achieved, the natural history of these two lesions might result in stroke and limb loss. A percutaneous contralateral limb approach was thought to be inadequate for left leg revascularization and at high risk for access site complication due to the multiple previous femoral surgical procedures (ABFGs). The subacute thrombosis of the left CCA was thought to be secondary to intimal injury during the recent PTCA performed through the postsurgical left leg vascular access.
Under local anesthesia in the endovascular operative suite, the left CFA and ABFG limb were surgically exposed and resected and an interposition seal PTFE (Vascutek USA Inc, a Terumo Company, Ann Arbor, MI) bypass graft was placed for revascularization of the left leg. Simultaneously, the left CCA stenosis was revascularized (stented) using the STG technique. The proximal anastomosis was performed and a long segment of excess graft was left available for the interventional procedure to be performed through; this excess portion of the graft was to be discarded later (Figure 1C). Standard needle, guidewire, and sheaths for the planned CCA intervention were then introduced through the excess graft, therefore utilizing the bypass graft as vascular access.
The CCA intervention was performed without a distal protection device using a 10-mm Protégé, nitinol, self-expanding stent (ev3, Minneapolis, MN), without complications (Figure 1D). The OEC 9800 plus mobile vascular unit (GE OEC Medical Systems, Salt Lake City, UT) was used for intraoperative vascular imaging and fluoroscopy. The excess graft was discarded and the distal anastomosis was performed, completing the limb revascularization (Figure 1E). Metallic anastomotic graft markers (AGMs) were placed to facilitate any future angiography and/or intervention (Figure 1E) because there has been documented reduction of contrast use, radiation exposure, procedural times, and catheter changes and manipulations after CABG when AGMs have been placed.5,6 The patient was asymptomatic at 12-month follow-up.
PTFE GRAFT AS VASCULAR ACCESS
Utilizing the graft as vascular access has several advantages, including facilitating the performance of angiography and the exchange of wires, sheaths, catheters, balloons, and stents, which can be cumbersome when attempted through a sheath placed in the native vessel or through a native vessel arteriotomy. Both of these native routes of intraoperative vascular access often offer limited space and mobility and are fraught with bleeding. Arterial repair can be difficult in these often calcified, fragile vessels, which are prone to dissections and postoperative stricture. We always advocate that endovascular interventions performed during open vascular surgical procedures in the endovascular operative suite be made through a sheath.
The STG technique allows ample room for sheath placement and manipulation within the graft conduit, avoiding the sheath space limitations of working within the native vessel. The length of the planned graft should be at least 10 cm longer than the needed bypass length, and the sheath “graftotomy” is placed well beyond the needed bypass length allowing disposal of that portion of the graft.
One patient population that may be particularly well suited for the STG technique is the true limb-salvage patient who presents with established tissue loss or ulceration (Rutherford Class 5-6) and inadequate or no venous bypass conduits, a long complex flush total occlusion of the SFA, a patent popliteal artery, and severe infrapopliteal disease with minimal or no distal runoff to the foot. Classically, these patients would require femoral-tibial bypass with a long autogeneous vein for limb salvage because these patients have no viable totally percutaneous options. The STG technique would allow an above-the-knee PTFE bypass, of which the 5-year patency rates are encouraging.7 It would also allow simultaneous popliteal and/or infrapopliteal outflow interventional revascularization options to this patient population that, if left unrevascularized, will have an amputation rate of 60% to 90%.8-10 The recent encouraging results of the LACI study11 (93% 6-month limb salvage rate) make excimer laser-assisted balloon angioplasty combined with the STG technique an attractive option for this patient population that would otherwise have minimal revascularization options.
Limited percutaneous vascular access continues to be a dilemma for the peripheral interventionalist, and it may necessitate a recommendation for surgical revascularization. As vascular surgeons gain catheter-based skills or develop a clinical partnership with interventional cardiologists or interventional radiologists, creative less-invasive revascularization options or combined hybrid procedures can be developed that will provide patients with improved outcomes. The hybrid STG technique has been utilized in our practice for simultaneous proximal and distal interventions during surgical bypass procedures, but this technique has not been well described in the literature. We believe this to be the first carotid intervention described using this technique. Surgeons and interventionalists alike need to be aware of its usefulness. Just as vascular surgeons are now becoming familiar with the interventional suite, the STG technique may allow the interventionalist to become more acquainted with the endovascular operative suite, therefore improving revascularization options in patients with complex PVD.
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 Cardiovascular 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.
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