Successful Ultrasound-Accelerated Thrombolysis of Acutely Occluded Right Aorto-Femoral Gore-Tex Bypass Graft

Acute peripheral artery thrombotic occlusion is a major clinical problem with significant long-term morbidity and mortality. If circulation is not rapidly restored, amputation/limb loss and/or death may occur. Multiple treatment approaches have been used for the treatment of acute limb ischemia: endovascular mechanical and chemical thrombolysis, surgical thrombectomy or direct percutaneous transluminal angioplasty and stent implantation, with varying degrees of success.¹ Occlusion of a bypass graft often results in recurrence of symptoms, ranging from intermittent claudication to acute or critical limb ischemia, depending on the acuity of occlusion and the presence of collateral circulation. 

Although studies have demonstrated that surgical thrombectomy and revascularization methods have a higher chance of technical success, these modalities also have a greater mortality risk.² Treatment options for acutely occluded bypass grafts are limited, as there is a paucity of data in the literature. 

Catheter-directed thrombolysis allows high-concentration therapeutic agents to be delivered directly to the affected vascular segments. High-frequency ultrasound is thought to increase the permeability of the thrombolytic agent into the thrombus through the fibrin strands, resulting in increased effectiveness. Ultrasound-accelerated catheter-directed thrombolysis through the EkoSonic Endovascular System (EKOS Corporation) has been successfully used for the management of deep venous thrombosis and pulmonary embolism. Its published use for the management  of acute lower extremity bypass occlusion is limited, however; only one 10-patient case series from Germany has been published³ as well as an additional case report.⁴ There are no studies using an ultrasound-enhanced EkoSonic catheter to treat acute thrombotic aorto-femoral bypass graft occlusions. Here, we present a patient who had an acute thrombotic occlusion of the right aorto-femoral bypass (Gore-Tex, Gore Medical) graft, following an endovascular infra-renal aortic stent placement, treated with Ekos thrombolytic therapy. 

Case study

A 72-year-old male with a history of aorto-bifemoral bypass grafting with a Gore-Tex graft 15 years prior presented with severe Rutherford Class III claudication pain that gradually worsened despite optimal medical therapy. Computed tomography (CT) angiography of the abdominal aorta revealed a severe stenosis of the infra-renal aorta and a mid-aortic stenosis. Invasive angiography (Figure 1) confirmed this finding and demonstrated stenosis of the proximal anastomosis of the infra-renal aorta and aorto-bifemoral bypass graft. It was felt that an endovascular stent cuff/graft would be the ideal treatment option in light of the prior bypass grafting. 

This was performed as a hybrid procedure. The surgeon performed an oblique incision in the right groin and carried the dissection down to the distal end of the aorto-femoral bypass, common femoral artery, and the bifurcation. An 18 French (Fr) sheath was placed in the right Gore-Tex graft. The interventional cardiologist cannulated the left side percutaneously and placed a 5 Fr sheath. An Endurant II stent (24 x 24 x 8.2 mm) (Medtronic) was deployed in the infra-renal aorta. Further angiography revealed some persistent narrowing in the graft, which was believed to be a thrombus (Figure 2), and an additional graft (25 x 25 x 4.9 mm) was placed. A Fogarty thrombectomy device (Edwards Lifesciences) was employed but did not retrieve a thrombus. 

The following morning, the patient developed pain, paresthesia, and coldness in his right lower extremity. CT angiogram revealed a massive clot in the right limb of the aorto-bifemoral graft. After a detailed discussion, it was decided that an endovascular approach would be optimal, as re-exploration of the right groin incision site would considerably increase chances of bleeding and infection. 

In the cardiac catheterization laboratory, the patient’s right posterior tibial artery was assessed with ultrasound guidance. A Glidewire Advantage wire (Terumo) with an .035-inch Quick-Cross catheter (Spectranetics) was used to cross the lesion retrograde. The wire repeatedly went to the native occluded iliac artery. Radial access was obtained, and angiography revealed stump occlusion of the right limb of the aorto-bifemoral graft (Figure 3), with the thrombus burden extending to the proximal portion of the superficial femoral artery and profunda femoris artery. An .035-inch Glidewire Advantage wire with a Quick-Cross catheter was used to cross the occluded segment. A 50 cm EkoSonic catheter was sent antegrade through the radial access site to the profunda femoris artery and a 30 cm Ekos catheter was sent retrograde through the posterior tibial access site (Figure 4). In each of the catheters, a 1 mg bolus of tissue plasminogen activator (tPA) was given. The drip was started at 0.5mg/hr through each catheter for a total of 1 mg/hr. A FemoStop device (St. Jude Medical) was placed at the femoral incision site to decrease the chance of bleeding from the previous day’s open repair and the patient was transferred to the intensive care unit (ICU). 

After 20 hours, the Ekos catheters were removed and angiography was repeated, which showed almost complete resolution of the thrombus in the right bypass graft, and the proximal superficial femoral artery and profunda femoris artery (Figure 5). There was haziness and stenosis at the edge of the stent graft to the right limb. After using an 8 x 20 mm balloon for predilation, a 9 x 29 mm Genesis stent (Cordis, a Cardinal Health company) was placed at the right limb of the graft at the ostial right common iliac. Angiography revealed no dissection or perforation, and good blood flow and runoff. At our patient’s two-month follow-up, CT angiography demonstrated a patent aorto-bifemoral graft and he was free of claudication pain. 

Discussion

Acute limb ischemia constitutes a medical emergency with significant morbidity and mortality. For our patient, who’d had an open repair of the right femoral graft the day before thrombosis developed in the graft, conventional surgical and endovascular techniques would have increased the risk of bleeding and infection. The ULTIMA trial, which randomized patients with intermediate-risk pulmonary embolism to unfractionated heparin and low-dose ultrasound-assisted catheter-directed thrombolysis or to unfractionated heparin alone, excluded patients who’d had major surgery from the Ekos group because of concerns of increased bleeding at the surgical sites.⁵ In our patient, surgical-site bleeding was a risk, so a FemoStop device was used at low pressure as a precaution. Also, a dual-access strategy with posterior tibial and radial accesses allowed us to double the delivery of ultrasound energy into the thrombus, while keeping the maximum thrombolytic dose at 1 mg/hr. This strategy was effective in our patient, as the flow was restored with near complete resolution of thrombus and no bleeding complications.

Optimal outcomes of endovascular techniques are limited by distal embolization and the no-reflow phenomenon, as is seen in coronary circulation thrombus. This is the Achilles’ heel of endovascular techniques. The pharmaco-mechanical thrombolysis methods described in the literature involve an initial mechanical strategy with prolonged duration of thrombolytic therapy.⁶ We believe initial Ekos catheter-guided thrombolytic therapy with subsequent percutaneous angioplasty/stent could be a better strategy to significantly decrease the chances of distal embolization.

Using the EkoSonic Endovascular System to manage acute thrombotic occlusion of bypass grafts is an intuitive approach that may also be faster, safer, and provide more complete thrombolysis than initial surgical or pharmaco-mechanical thrombolysis. Recent surgery might not be an absolute contraindication for Ekos thrombolytic therapy if appropriate precautions are taken. This could have potential implications in patients with post-surgical deep venous thrombosis, pulmonary embolism, and arterial thrombosis.

References

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3. Wissgott C, Kamusella P, Richter A, Klein-Weigel P, Schink T, Steinkamp HJ. Treatment of acute femoropopliteal bypass graft occlusion: Comparison of mechanical rotational thrombectomy with ultrasound-enhanced lysis. Rofo. 2008; 180(6): 547-552.
4. Marmagkiolis K, Lendel V, Cilingiroglu M. EKOS ultrasound-accelerated catheter-directed thrombolysis for acutely occluded femoro-popliteal graft. Cardiovasc Revasc Med. 2014; 15(1):43-45.
5. Kucher N, Boekstegers P, Müller OJ, Kupatt C, Beyer-Westendorf J, Heitzer T, et al. Randomized, controlled trial of ultrasound-assisted catheter-directed thrombolysis for acute intermediate-risk pulmonary embolism. Circulation. 2014; 129(4): 479-486.
6. Byrne RM, Taha AG, Avgerinos E, Marone LK, Makaroun MS, Chaer RA. Contemporary outcomes of endovascular interventions for acute limb ischemia. J Vasc Surg. 2014; 59(4): 988-995.

Disclosures: Dr. Joji Varghese and Dr. David Carlson report no conflicts of interest regarding the content herein.