- Email: [email protected]
Stent Implantation for Acute Iliac Artery Occlusions: Initial Experience
Stent Implantation for Acute Iliac Artery Occlusions: Initial Experience Viktor Berczi, MD, PhD, Steven M. Thomas, MRCP, FRCR, Douglas R. Turner, MRCP, FRCR, John R. Bottomley, MB, ChB, FRANZCR, Trevor J. Cleveland, FRCS, FRCR, and Peter A. Gaines, FRCP, FRCR
PURPOSE: Treatment options for acute occlusion of the iliac arteries include surgical thrombectomy, surgical bypass, and endovascular interventions such as thrombolysis and mechanical thrombectomy with or without adjunctive angioplasty or stent implantation. Acute lesions are not usually treated by stent implantation for fear of distal embolism. The purpose of this study was to retrospectively review a single-center experience of primary iliac stent implantation for acute ischemia secondary to acute thrombosis. MATERIALS AND METHODS: Between April 2004 and August 2005, seven patients (five men and two women; mean age, 69.9 y; range, 53–93 y) underwent iliac stent implantation for the acute onset (within 12 days before presentation) of ipsilateral ischemic symptoms. Diagnostic angiography revealed occlusion of the common and external iliac arteries (n ⴝ 3) or external iliac artery (n ⴝ 4). Patients with rest pain (n ⴝ 6) were treated with unfractionated heparin. RESULTS: All acute occlusions were traversed by the guide wire with relative ease. Recanalization with stent implantation was successful in all cases without distal embolization. Five patients showed noticeable clinical improvement. Two elderly patients with isolated patent profunda segments with no demonstrable distal runoff vessels did not have long-term clinical improvement despite successful iliac recanalization. CONCLUSIONS: This small case series suggests that primary stent implantation for acute iliac occlusions with a patent common femoral artery under intravenous heparin protection may be a reasonable endovascular alternative to thrombolysis for patients who cannot tolerate the time delay to achieve thrombolysis or who have contraindications to thrombolysis. The safety of this technique may be comparable to that of primary stent implantation for chronic occlusions, but larger series would be necessary to confirm this. J Vasc Interv Radiol 2006; 17:645– 649 Abbreviation:
US ⫽ ultrasound
TREATMENT options for acute occlusion of the iliac arteries include surgical thrombectomy, surgical bypass, and endovascular interventions such as thrombolysis and mechanical thrombectomy with or without ad-
From the Sheffield Vascular Institute, Northern General Hospital, Sheffield, United Kingdom. Received September 8, 2005; revision requested; revision received and accepted December 25. Address correspondence to V.B., Vascular Radiology, Northern General Hospital, Herries Road, Sheffield, S5 7AU, UK; E-mail: [email protected] V.B. is undertaking an Endovascular Fellowship funded by Cordis/Johnson & Johnson UK. None of the authors have identified a conflict of interest. © SIR, 2006 DOI: 10.1097/01.RVI.0000203918.91835.73
junctive angioplasty or stent implantation (1–5). The incidences of perioperative mortality and morbidity associated with the surgical options can be high (8%–27%) (1– 4). Primary endovascular stent placement in the context of acute lesions is not usually considered because of the fear of distal embolism, but few data support or refute this assertion. Additional concerns include the lack of knowledge of issues such as patency rates, length of stent coverage required, stent placement across the internal iliac artery, and incomplete stent opening as a result of compressed thrombus between the stent and arterial wall. The purpose of this study was to retrospectively review technical success, perioperative complications, and
clinical outcomes in patients treated at a single center with primary iliac stent implantation for ischemia as a result of acute occlusion of an iliac artery.
MATERIALS AND METHODS Between April 2004 and August 2005, seven patients (five men and two women; mean age, 69.9 y; range, 53–93 y) were identified who underwent iliac stent implantation after acute onset of ipsilateral ischemic symptoms (mean duration from onset, 4.3 d; range, 1–10 d). Diagnostic angiography revealed occlusion of the common and external iliac arteries (n ⫽ 3) or external iliac artery (n ⫽ 4), which was considered in all cases to be a result of acute arterial thrombosis complicating
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•
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Stent Implantation for Acute Iliac Artery Occlusions
atheromatous arterial disease. Our institution does not require any approval for retrospective analysis of our practice. All patients gave their consent after receiving detailed information about the risks and benefits of the endovascular procedure and other treatment options, including surgery and thrombolysis. Diagnostic angiography was performed with placement of a 4-F pigtail catheter (Cordis Europa, Roden, The Netherlands) in the infrarenal abdominal aorta from the contralateral common femoral artery (to the acute iliac occlusion). In all cases, an iliac occlusion with patency of the common femoral artery was found. The patent common femoral artery allowed access for endovascular intervention. In all instances, the ipsilateral common femoral artery was then accessed with use of US guidance. A 6-F Britetip sheath (Cordis Europa) was positioned in the common femoral artery. The acute iliac occlusion was generally traversed with a straight 0.035-inch guide wire (TSF-35-145; William Cook Europe, Bjaeverskov, Denmark) or a Terumo Radiofocus guide wire (Terumo, Tokyo, Japan) directed by a curved catheter (Cobra; Cordis Europa). A 3-mm J-tipped guide wire (William Cook Europe) was used in one case of an acutely occluded stent to decrease the risk of crossing the stent struts during recanalization. Guide wire passage across the occluded segments was achieved easily in all cases. The acute occlusion was treated by primary placement of Luminexx (Bard, Karlsruhe, Germany; n ⫽ 5) or Smart (Cordis Europa; n ⫽ 2) stents (8 –10 mm in diameter and 50 – 100 mm long as appropriate) followed by dilation with balloons 7–9 mm in diameter. Hemostasis was achieved by manual compression (n ⫽ 5) or with use of closure devices, namely the Perclose (Abbott Vascular, Redwood City, CA; n ⫽ 1) or Angioseal device (St. Jude Medical, Minnetonka, MN; n ⫽ 1). Patients with rest pain (n ⫽ 6) received unfractionated heparin (Leo Laboratories, Princess Risborough, UK) according to hospital protocol before the endovascular procedure. Patients received a 5,000-U loading dose followed by weight-adjusted administration of 20 U/kg/h, and activated partial thromboplastin time was
checked 6 hours after infusion. If the ratio was in the therapeutic range (ie, 1.8 –2.7), activated partial thromboplastin time was checked daily. If it was out of the therapeutic range, the dose was adjusted and the activated partial thromboplastin time was rechecked every 6 hours. All procedures were performed with the patient receiving therapeutic anticoagulation.
RESULTS Acute stent placement and subsequent angioplasty was technically successful in all seven cases. In two cases of common and external iliac artery occlusion, two overlapping stents were inserted. Good morphologic results were achieved and residual stenosis was less than 30% in each instance. An illustrative case is shown in the Figure. Distal embolization was not seen in any of the cases; direct imaging of the outflow vessels was performed in five cases. In two cases, the lack of distal embolization was assessed on the basis of the rapid flow in the femoral arteries; there were no clinically significant embolic complications in these patients. Foot pulses were restored in cases in which the superficial femoral artery was not occluded. Presenting symptoms included acute-onset, short-distance (⬍10 meters) intermittent claudication (n ⫽ 1) that improved to several hundred meters after stent implantation. Six other patients had rest pain with concomitant numbness or decreased movement; rest pain was no longer present (n ⫽ 5) or was eased (n ⫽ 1) after stent placement. In one case, iliac stent implantation was performed immediately after diagnostic arteriography on the severely ischemic limb to achieve improved lower limb perfusion without any delay. Diagnostic angiography also showed diseased common femoral and profunda femoral arteries and an embolic occlusion of the popliteal artery (that had occurred before iliac stent implantation); on the same day, popliteal embolectomy, common femoral endarterectomy, and patch angioplasty and fasciotomy were performed after acute iliac stent placement. In another patient, despite a technically successful revascularization procedure, muscle necrosis was found
JVIR
during fasciotomy the following day, and amputation was performed. In this patient, angiography before revascularization showed a sole runoff in the form of a patent profunda femoris artery. After acute iliac stent implantation, the profunda femoris artery remained patent with distal reconstitution of the above-knee popliteal artery and runoff in the form of the posterior tibial artery as the sole crural vessel. In a 93-year-old patient with questionable viability of the foot, angiography showed an isolated patent profunda femoris artery segment with no demonstrable distal runoff vessels; rest pain was reduced after successful iliac stent placement, but the foot remained ischemic as a result of a lack of crural flow, and the patient died 10 days later of septicemia and heart failure.
DISCUSSION The cases presented involve an established endovascular technique— endovascular stent placement—in circumstances in which many interventionalists believe there are increased risks, namely in acutely thrombosed vessels. The main concern is that the artery contains fresh soft thrombus that will prolapse through the stent struts and/or embolize distally. This did not appear to be a problem in the cases described herein. Recently, successful stent placement and the use of the stent-in-stent technique were also reported in cases of progressive stroke to treat acute intracranial internal carotid artery occlusion (6). Easy traversal of the occlusion with the guide wire suggests that the thrombus was indeed soft in all cases, but presumably the stent was able to trap the thrombus against the arterial wall. In all our cases, we were able to achieve angiographic improvement, and we were able to achieve clinical improvement in five of seven cases, indicating effective revascularization. The clinical circumstances we encountered in these cases were those of acutely ischemic limbs that required revascularization secondary to thrombotic occlusion of the iliac artery. Complete vascular occlusion with severe ischemia will lead to extensive tissue necrosis within 6 –24 hours unless the limb is revascularized. If the ischemic tissue damage is extensive
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Figure. A 53-year-old man presented with acute right lower limb ischemia and severe rest pain. (a) Femoral angiography demonstrates occluded right common and external iliac arteries with a patent common femoral artery. Patency of the underfilled right common femoral is confirmed on US before intervention. (b) Diagnostic angiography also reveals an occluded popliteal artery. Insertion of 10-mm ⫻ 100-mm and 9-mm ⫻ 50-mm Luminexx stents with subsequent angioplasty (9 mm for the common iliac artery, 8 mm for the external iliac artery) results in successful recanalization of the acutely occluded iliac arteries (c) without distal embolization.
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and there is a risk of reperfusion injury or little likelihood that the limb will return to function, even with limb revascularization, urgent amputation should be performed. In many cases, the degree of acute ischemia does not require such urgent treatment, even though the limb may still be threatened. Initial management in all cases should involve the use of intravenous heparin to prevent or limit propagation of thrombus and to protect collateral vessels. In six of the seven cases described herein, heparin administration was instituted before angiography and intervention. In the other case, the degree of limb ischemia was not believed to be limb threatening, and heparinization was not instituted. As is our usual practice, heparin was used for the stent implantation procedure. The risk of distal embolization during iliac percutaneous transluminal angioplasty and stent implantation is usually lower than 10% (7–11). Many studies suggest that primary stent implantation decreases the risk of distal embolization in comparison with angioplasty alone (8 –10). A study of 101 patients with chronic occlusions demonstrated a 10% overall incidence of distal embolization (8); the two subgroups in the study (stent implantation after angioplasty vs primary stent implantation) had remarkably different distal embolization rates (30% vs 4%, respectively). Rees et al (12) treated five acutely occluded iliac arteries with urokinase, percutaneous transluminal angioplasty, and stent placement without any distal embolization. In the same study (12), there were two cases of embolization among the seven patients who underwent the same treatment regimen for chronically occluded iliac arteries. Our study showed no clinically significant embolic complications in seven cases; this was proved angiographically in five of the cases. We are not aware of any other report of stent implantation alone in acute iliac occlusions. Therefore, the data compiled thus far do not support the fear that distal embolization would occur more frequently in acute than in chronic iliac occlusions. Treatment of more cases is needed to enable the compilation of robust data. An alternative approach might have involved the use of a covered stent (ie, stent-graft), but our results
suggest this is unnecessary, and the use of these devices would considerably increase the cost of the procedure and may require much larger access sheaths, requiring percutaneous closure device placement (as a result of aggressive anticoagulation in these patients) or a cutdown. A problem with the approach described herein is that it is possible only if the common femoral artery and at least one runoff vessel are patent to achieve effective limb revascularization. Traditional surgical approaches may involve thrombectomy with use of a Fogarty balloon, direct extraction of thrombus, or bypass grafting. For in situ thrombosis of the iliac artery, thrombectomy with a Fogarty balloon would probably be the first-line surgical approach. Even though this may extract the thrombus, any residual stenotic disease requires further treatment with balloon angioplasty or stent implantation. The advantage of this approach is that the runoff is protected as the thrombus is extracted, and if there is evidence of distal embolization requiring treatment, this can be achieved at the same time. However, mortality rates after surgical thrombectomy can be high (8%–27%) (1– 4). Another alternative would be to consider thrombolysis to chemically dissolve the thrombus. Again, for iliac thrombosis, this will usually reveal underlying arterial occlusive disease requiring further endovascular treatment. If, as in the majority of our cases, the runoff is preserved before treatment, there is a risk that thrombus will embolize distally during thrombolysis. Even though this may be treated with further thrombolysis, success is not guaranteed. Thrombolysis procedures per se may be prolonged and labor intensive, and they can have serious side effects, the most dangerous of which are hemorrhage and stroke (3). To avoid the risks of thrombolysis, the use of mechanical thrombectomy devices is another way to remove thrombus. Most of these rely on producing a Venturi effect at their tip mechanically or with a jet of fluid and macerating the thrombus. There is little evidence that they are effective, and adjuvant thrombolysis is often required, even though the amount of lytic agent required may be reduced as
April 2006
JVIR
a result of thrombus debulking by the thrombectomy device (5). Limitations of this preliminary study include its retrospective nature and the lack of direct imaging of the outflow vessels after stent placement and angioplasty in two of the seven cases. However, in both these cases, rapid flow in the femoral arteries and clinical improvement indicated the lack of significant distal embolization. This small case series suggests that primary stent implantation for acute iliac occlusions with a patent common femoral artery with intravenous heparin protection may be a reasonable endovascular alternative to thrombolysis for patients who cannot tolerate the time delay to achieve thrombolysis or who have contraindications to thrombolysis or surgery. The safety of this technique may be comparable to that of primary stent implantation of chronic occlusions, but larger series would be necessary to confirm this. References 1. Blaisdell FW, Steele M, Allen RE. Management of acute lower extremity arterial ischemia due to embolism and thrombosis. Surgery 1978; 84: 822–834. 2. The STILE investigators. Results of a prospective randomized trial evaluating surgery versus thrombolysis for ischemia of the lower extremity: the STILE trial. Ann Surg 1994;220: 251–266. 3. Ouriel K, Veith FJ, Sasahara AA. A comparison of recombinant urokinase with vascular surgery as initial treatment for acute arterial occlusion of the legs. Thrombolysis or Peripheral Arterial Surgery (TOPAS) Investigators. N Engl J Med 1998; 338:1105–1111. 4. Kaliszky P, Jambor G, Nagy Z, et al. Early results after aortoiliac reconstruction in our department in the past six years. Magy Seb 2003; 56:103–107. 5. Gould D. Mechanical thrombectomy: is it worthwhile? In: Wyatt MG, Watkinson AF, eds. Endovascular intervention: current controversies. Shrewsbury, UK: TFM Publishing Ltd, 2004;187–198. 6. Okazaki T, Satomi J, Satoh K, et al. Rescue revascularization therapy with a stent-in-stent technique for acute intracranial internal carotid artery occlusion. Neurol Med Chir (Tokyo) 2005; 45:253–258. 7. Vorwerk D, Guenther RW, Schurmann K, et al. Primary stent placement for
Volume 17
Number 4
chronic iliac artery occlusions: follow-up results in 103 patients. Radiology 1995; 194:745–749. 8. Sapoval MR, Long AL, Pagny JY, et al. Outcome of percutaneous intervention in iliac artery stents. Radiology 1996; 198:481–486. 9. Dyet JF, Gaines PA, Nicholson AA, et al. Treatment of chronic iliac artery
Berczi et al
occlusions by means of percutaneous endovascular stent placement. J Vasc Interv Radiol 1997; 8:349–353. 10. Reyes R, Maynar M, Lopera J, et al. Treatment of chronic iliac artery occlusions with guide wire recanalization and primary stent placement. J Vasc Interv Radiol 1997; 8:1049–1055. 11. Gaines PA, Schulte KL, Muller-Huls-
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beck S, et al. A multicentre evaluation of the Medtronic AVE flexible Iliac Bridge stent in the iliac arteries (the first study). Eur J Vasc Endovasc Surg 2005; 29:124–130. 12. Rees CR, Palmaz JC, Garcia O, et al. Angioplasty and stenting of completely occluded iliac arteries. Radiology 1989; 172(suppl 2):953–959.
PURPOSE: Treatment options for acute occlusion of the iliac arteries include surgical thrombectomy, surgical bypass, and endovascular interventions such as thrombolysis and mechanical thrombectomy with or without adjunctive angioplasty or stent implantation. Acute lesions are not usually treated by stent implantation for fear of distal embolism. The purpose of this study was to retrospectively review a single-center experience of primary iliac stent implantation for acute ischemia secondary to acute thrombosis. MATERIALS AND METHODS: Between April 2004 and August 2005, seven patients (five men and two women; mean age, 69.9 y; range, 53–93 y) underwent iliac stent implantation for the acute onset (within 12 days before presentation) of ipsilateral ischemic symptoms. Diagnostic angiography revealed occlusion of the common and external iliac arteries (n ⴝ 3) or external iliac artery (n ⴝ 4). Patients with rest pain (n ⴝ 6) were treated with unfractionated heparin. RESULTS: All acute occlusions were traversed by the guide wire with relative ease. Recanalization with stent implantation was successful in all cases without distal embolization. Five patients showed noticeable clinical improvement. Two elderly patients with isolated patent profunda segments with no demonstrable distal runoff vessels did not have long-term clinical improvement despite successful iliac recanalization. CONCLUSIONS: This small case series suggests that primary stent implantation for acute iliac occlusions with a patent common femoral artery under intravenous heparin protection may be a reasonable endovascular alternative to thrombolysis for patients who cannot tolerate the time delay to achieve thrombolysis or who have contraindications to thrombolysis. The safety of this technique may be comparable to that of primary stent implantation for chronic occlusions, but larger series would be necessary to confirm this. J Vasc Interv Radiol 2006; 17:645– 649 Abbreviation:
US ⫽ ultrasound
TREATMENT options for acute occlusion of the iliac arteries include surgical thrombectomy, surgical bypass, and endovascular interventions such as thrombolysis and mechanical thrombectomy with or without ad-
From the Sheffield Vascular Institute, Northern General Hospital, Sheffield, United Kingdom. Received September 8, 2005; revision requested; revision received and accepted December 25. Address correspondence to V.B., Vascular Radiology, Northern General Hospital, Herries Road, Sheffield, S5 7AU, UK; E-mail: [email protected] V.B. is undertaking an Endovascular Fellowship funded by Cordis/Johnson & Johnson UK. None of the authors have identified a conflict of interest. © SIR, 2006 DOI: 10.1097/01.RVI.0000203918.91835.73
junctive angioplasty or stent implantation (1–5). The incidences of perioperative mortality and morbidity associated with the surgical options can be high (8%–27%) (1– 4). Primary endovascular stent placement in the context of acute lesions is not usually considered because of the fear of distal embolism, but few data support or refute this assertion. Additional concerns include the lack of knowledge of issues such as patency rates, length of stent coverage required, stent placement across the internal iliac artery, and incomplete stent opening as a result of compressed thrombus between the stent and arterial wall. The purpose of this study was to retrospectively review technical success, perioperative complications, and
clinical outcomes in patients treated at a single center with primary iliac stent implantation for ischemia as a result of acute occlusion of an iliac artery.
MATERIALS AND METHODS Between April 2004 and August 2005, seven patients (five men and two women; mean age, 69.9 y; range, 53–93 y) were identified who underwent iliac stent implantation after acute onset of ipsilateral ischemic symptoms (mean duration from onset, 4.3 d; range, 1–10 d). Diagnostic angiography revealed occlusion of the common and external iliac arteries (n ⫽ 3) or external iliac artery (n ⫽ 4), which was considered in all cases to be a result of acute arterial thrombosis complicating
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Stent Implantation for Acute Iliac Artery Occlusions
atheromatous arterial disease. Our institution does not require any approval for retrospective analysis of our practice. All patients gave their consent after receiving detailed information about the risks and benefits of the endovascular procedure and other treatment options, including surgery and thrombolysis. Diagnostic angiography was performed with placement of a 4-F pigtail catheter (Cordis Europa, Roden, The Netherlands) in the infrarenal abdominal aorta from the contralateral common femoral artery (to the acute iliac occlusion). In all cases, an iliac occlusion with patency of the common femoral artery was found. The patent common femoral artery allowed access for endovascular intervention. In all instances, the ipsilateral common femoral artery was then accessed with use of US guidance. A 6-F Britetip sheath (Cordis Europa) was positioned in the common femoral artery. The acute iliac occlusion was generally traversed with a straight 0.035-inch guide wire (TSF-35-145; William Cook Europe, Bjaeverskov, Denmark) or a Terumo Radiofocus guide wire (Terumo, Tokyo, Japan) directed by a curved catheter (Cobra; Cordis Europa). A 3-mm J-tipped guide wire (William Cook Europe) was used in one case of an acutely occluded stent to decrease the risk of crossing the stent struts during recanalization. Guide wire passage across the occluded segments was achieved easily in all cases. The acute occlusion was treated by primary placement of Luminexx (Bard, Karlsruhe, Germany; n ⫽ 5) or Smart (Cordis Europa; n ⫽ 2) stents (8 –10 mm in diameter and 50 – 100 mm long as appropriate) followed by dilation with balloons 7–9 mm in diameter. Hemostasis was achieved by manual compression (n ⫽ 5) or with use of closure devices, namely the Perclose (Abbott Vascular, Redwood City, CA; n ⫽ 1) or Angioseal device (St. Jude Medical, Minnetonka, MN; n ⫽ 1). Patients with rest pain (n ⫽ 6) received unfractionated heparin (Leo Laboratories, Princess Risborough, UK) according to hospital protocol before the endovascular procedure. Patients received a 5,000-U loading dose followed by weight-adjusted administration of 20 U/kg/h, and activated partial thromboplastin time was
checked 6 hours after infusion. If the ratio was in the therapeutic range (ie, 1.8 –2.7), activated partial thromboplastin time was checked daily. If it was out of the therapeutic range, the dose was adjusted and the activated partial thromboplastin time was rechecked every 6 hours. All procedures were performed with the patient receiving therapeutic anticoagulation.
RESULTS Acute stent placement and subsequent angioplasty was technically successful in all seven cases. In two cases of common and external iliac artery occlusion, two overlapping stents were inserted. Good morphologic results were achieved and residual stenosis was less than 30% in each instance. An illustrative case is shown in the Figure. Distal embolization was not seen in any of the cases; direct imaging of the outflow vessels was performed in five cases. In two cases, the lack of distal embolization was assessed on the basis of the rapid flow in the femoral arteries; there were no clinically significant embolic complications in these patients. Foot pulses were restored in cases in which the superficial femoral artery was not occluded. Presenting symptoms included acute-onset, short-distance (⬍10 meters) intermittent claudication (n ⫽ 1) that improved to several hundred meters after stent implantation. Six other patients had rest pain with concomitant numbness or decreased movement; rest pain was no longer present (n ⫽ 5) or was eased (n ⫽ 1) after stent placement. In one case, iliac stent implantation was performed immediately after diagnostic arteriography on the severely ischemic limb to achieve improved lower limb perfusion without any delay. Diagnostic angiography also showed diseased common femoral and profunda femoral arteries and an embolic occlusion of the popliteal artery (that had occurred before iliac stent implantation); on the same day, popliteal embolectomy, common femoral endarterectomy, and patch angioplasty and fasciotomy were performed after acute iliac stent placement. In another patient, despite a technically successful revascularization procedure, muscle necrosis was found
JVIR
during fasciotomy the following day, and amputation was performed. In this patient, angiography before revascularization showed a sole runoff in the form of a patent profunda femoris artery. After acute iliac stent implantation, the profunda femoris artery remained patent with distal reconstitution of the above-knee popliteal artery and runoff in the form of the posterior tibial artery as the sole crural vessel. In a 93-year-old patient with questionable viability of the foot, angiography showed an isolated patent profunda femoris artery segment with no demonstrable distal runoff vessels; rest pain was reduced after successful iliac stent placement, but the foot remained ischemic as a result of a lack of crural flow, and the patient died 10 days later of septicemia and heart failure.
DISCUSSION The cases presented involve an established endovascular technique— endovascular stent placement—in circumstances in which many interventionalists believe there are increased risks, namely in acutely thrombosed vessels. The main concern is that the artery contains fresh soft thrombus that will prolapse through the stent struts and/or embolize distally. This did not appear to be a problem in the cases described herein. Recently, successful stent placement and the use of the stent-in-stent technique were also reported in cases of progressive stroke to treat acute intracranial internal carotid artery occlusion (6). Easy traversal of the occlusion with the guide wire suggests that the thrombus was indeed soft in all cases, but presumably the stent was able to trap the thrombus against the arterial wall. In all our cases, we were able to achieve angiographic improvement, and we were able to achieve clinical improvement in five of seven cases, indicating effective revascularization. The clinical circumstances we encountered in these cases were those of acutely ischemic limbs that required revascularization secondary to thrombotic occlusion of the iliac artery. Complete vascular occlusion with severe ischemia will lead to extensive tissue necrosis within 6 –24 hours unless the limb is revascularized. If the ischemic tissue damage is extensive
Volume 17
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Berczi et al
•
647
Figure. A 53-year-old man presented with acute right lower limb ischemia and severe rest pain. (a) Femoral angiography demonstrates occluded right common and external iliac arteries with a patent common femoral artery. Patency of the underfilled right common femoral is confirmed on US before intervention. (b) Diagnostic angiography also reveals an occluded popliteal artery. Insertion of 10-mm ⫻ 100-mm and 9-mm ⫻ 50-mm Luminexx stents with subsequent angioplasty (9 mm for the common iliac artery, 8 mm for the external iliac artery) results in successful recanalization of the acutely occluded iliac arteries (c) without distal embolization.
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and there is a risk of reperfusion injury or little likelihood that the limb will return to function, even with limb revascularization, urgent amputation should be performed. In many cases, the degree of acute ischemia does not require such urgent treatment, even though the limb may still be threatened. Initial management in all cases should involve the use of intravenous heparin to prevent or limit propagation of thrombus and to protect collateral vessels. In six of the seven cases described herein, heparin administration was instituted before angiography and intervention. In the other case, the degree of limb ischemia was not believed to be limb threatening, and heparinization was not instituted. As is our usual practice, heparin was used for the stent implantation procedure. The risk of distal embolization during iliac percutaneous transluminal angioplasty and stent implantation is usually lower than 10% (7–11). Many studies suggest that primary stent implantation decreases the risk of distal embolization in comparison with angioplasty alone (8 –10). A study of 101 patients with chronic occlusions demonstrated a 10% overall incidence of distal embolization (8); the two subgroups in the study (stent implantation after angioplasty vs primary stent implantation) had remarkably different distal embolization rates (30% vs 4%, respectively). Rees et al (12) treated five acutely occluded iliac arteries with urokinase, percutaneous transluminal angioplasty, and stent placement without any distal embolization. In the same study (12), there were two cases of embolization among the seven patients who underwent the same treatment regimen for chronically occluded iliac arteries. Our study showed no clinically significant embolic complications in seven cases; this was proved angiographically in five of the cases. We are not aware of any other report of stent implantation alone in acute iliac occlusions. Therefore, the data compiled thus far do not support the fear that distal embolization would occur more frequently in acute than in chronic iliac occlusions. Treatment of more cases is needed to enable the compilation of robust data. An alternative approach might have involved the use of a covered stent (ie, stent-graft), but our results
suggest this is unnecessary, and the use of these devices would considerably increase the cost of the procedure and may require much larger access sheaths, requiring percutaneous closure device placement (as a result of aggressive anticoagulation in these patients) or a cutdown. A problem with the approach described herein is that it is possible only if the common femoral artery and at least one runoff vessel are patent to achieve effective limb revascularization. Traditional surgical approaches may involve thrombectomy with use of a Fogarty balloon, direct extraction of thrombus, or bypass grafting. For in situ thrombosis of the iliac artery, thrombectomy with a Fogarty balloon would probably be the first-line surgical approach. Even though this may extract the thrombus, any residual stenotic disease requires further treatment with balloon angioplasty or stent implantation. The advantage of this approach is that the runoff is protected as the thrombus is extracted, and if there is evidence of distal embolization requiring treatment, this can be achieved at the same time. However, mortality rates after surgical thrombectomy can be high (8%–27%) (1– 4). Another alternative would be to consider thrombolysis to chemically dissolve the thrombus. Again, for iliac thrombosis, this will usually reveal underlying arterial occlusive disease requiring further endovascular treatment. If, as in the majority of our cases, the runoff is preserved before treatment, there is a risk that thrombus will embolize distally during thrombolysis. Even though this may be treated with further thrombolysis, success is not guaranteed. Thrombolysis procedures per se may be prolonged and labor intensive, and they can have serious side effects, the most dangerous of which are hemorrhage and stroke (3). To avoid the risks of thrombolysis, the use of mechanical thrombectomy devices is another way to remove thrombus. Most of these rely on producing a Venturi effect at their tip mechanically or with a jet of fluid and macerating the thrombus. There is little evidence that they are effective, and adjuvant thrombolysis is often required, even though the amount of lytic agent required may be reduced as
April 2006
JVIR
a result of thrombus debulking by the thrombectomy device (5). Limitations of this preliminary study include its retrospective nature and the lack of direct imaging of the outflow vessels after stent placement and angioplasty in two of the seven cases. However, in both these cases, rapid flow in the femoral arteries and clinical improvement indicated the lack of significant distal embolization. This small case series suggests that primary stent implantation for acute iliac occlusions with a patent common femoral artery with intravenous heparin protection may be a reasonable endovascular alternative to thrombolysis for patients who cannot tolerate the time delay to achieve thrombolysis or who have contraindications to thrombolysis or surgery. The safety of this technique may be comparable to that of primary stent implantation of chronic occlusions, but larger series would be necessary to confirm this. References 1. Blaisdell FW, Steele M, Allen RE. Management of acute lower extremity arterial ischemia due to embolism and thrombosis. Surgery 1978; 84: 822–834. 2. The STILE investigators. Results of a prospective randomized trial evaluating surgery versus thrombolysis for ischemia of the lower extremity: the STILE trial. Ann Surg 1994;220: 251–266. 3. Ouriel K, Veith FJ, Sasahara AA. A comparison of recombinant urokinase with vascular surgery as initial treatment for acute arterial occlusion of the legs. Thrombolysis or Peripheral Arterial Surgery (TOPAS) Investigators. N Engl J Med 1998; 338:1105–1111. 4. Kaliszky P, Jambor G, Nagy Z, et al. Early results after aortoiliac reconstruction in our department in the past six years. Magy Seb 2003; 56:103–107. 5. Gould D. Mechanical thrombectomy: is it worthwhile? In: Wyatt MG, Watkinson AF, eds. Endovascular intervention: current controversies. Shrewsbury, UK: TFM Publishing Ltd, 2004;187–198. 6. Okazaki T, Satomi J, Satoh K, et al. Rescue revascularization therapy with a stent-in-stent technique for acute intracranial internal carotid artery occlusion. Neurol Med Chir (Tokyo) 2005; 45:253–258. 7. Vorwerk D, Guenther RW, Schurmann K, et al. Primary stent placement for
Volume 17
Number 4
chronic iliac artery occlusions: follow-up results in 103 patients. Radiology 1995; 194:745–749. 8. Sapoval MR, Long AL, Pagny JY, et al. Outcome of percutaneous intervention in iliac artery stents. Radiology 1996; 198:481–486. 9. Dyet JF, Gaines PA, Nicholson AA, et al. Treatment of chronic iliac artery
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