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Recanalization of an Occluded Aortoiliac Bypass Graft with Palmaz Stents
Case Report
Recanalization of an Occluded Aortoiliac Bypass Graft with Palmaz Stents 1 Michael C. Soulen, MD2 Joseph Bonn, MD Marcelle J. Shapiro, MD
Index terms: Arteries, grafts and prostheses, 98.452, 98.456 • Grafts, interventional procedures, 98.452, 98.456 • Grafts, stenosis or obstruction, 98.452 • Stents JVIR 1991; 2:497-501
Four tandem Palmaz balloon-expandable vascular stents were used to recanalize the completely occluded limb of an aortoiliac bypass graft after failure of thrombolysis and conventional angioplasty. The resting peak-systolic pressure gradient across the occluded limb was reduced from 68 to 13 mm Hg. The patient's rest pain resolved, and the anklebrachial index rose from 0.54 to 0.78. No embolization or stent-related complications occurred. The graft remains patent as determined with noninvasive studies obtained 8 months later. PERCUTANEOUS recanalization of occluded suprainguinal bypass grafts has a technical failure rate of approximately 10% (1-3). We describe salvage of an occluded limb of an aortoiliac bypass graft with Palmaz balloon-expandable stents (Johnson & Johnson Interventional Systems, Warren, NJ) after the failure of recanalization with thrombolysis and conventional angioplasty.
CASE REPORT
1 From the Division of Cardiovascular IInterventional Radiology, Thomas Jefferson University Hospital, 111 S 11th St, Suite 5609 Gibbon Bldg, Philadelphia, PA 19107. Received April 8, 1991; revision requested July 5, revision received August 20, accepted August 26. Address reprint requests to J.B. 2 Current address: Department of Radiology, Hospital of the University ofPennsylvania, Philadelphia.
©
SCVIR, 1991
A 60-year-old woman presented with a 6-month history of recurrent bilateral lower extremity claudication progressing gradually to rest pain. An end-toside Dacron aorto-bi-common-iliac bypass graft had been placed 3 years previously for a distal aortic occlusion, after which she had been asymptomatic. At that time the runoff vessels distal to the graft were normal bilaterally. Her past medical history was significant for hypertension requiring threedrug therapy, obesity, placement of an ileal conduit for a neuropathic bladder secondary to cerebral palsy, and a failed synthetic mesh abdominal herniorrhaphy. She had no history of diabetes, cardiac or cerebrovascular disease, or smoking. On physical examination her legs were pale. No pulses were palpable in the right leg, and only a weak femoral pulse was felt on the left. There was no dependent rubor or skin changes. She ambulated slowly with a walker due to neuromuscular deficits from her
cerebral palsy. Plain radiographs of the pelvis revealed a mild chronic deformity of the left hip. Ankle-brachial indexes were 1.07 on the left and 0.54 on the right. Results of serum laboratory studies were normal except for a mildly elevated creatinine level of 1.6 mg/dL (141 fLmol!L) (normal, < 1.5 mg/dL [133 fLmol!L)). Her subjective complaints of rest pain were out of proportion to her ankle-brachial indexes. It was difficult to determine how much of her pain was due to vascular insufficiency and how much may have been musculoskeletal pain related to her cerebral palsy, but the deterioration of her right anklebrachial index and loss of pulses in the right leg were new, objective findings according to the referring surgeon. Diagnostic arteriography was performed from a distal left brachial artery puncture due to an absent right femoral pulse and a markedly diminished left femoral pulse in this obese patient, leading to a suspicion of bilateral graft disease prior to arteriography. The right limb of the graft was found to be occluded just distal to its origin, with reconstitution of the distal right common iliac artery via collaterals (Fig 1a). The left limb of the graft and the runoff vessels of both lower extremities were patent. The origin of the occluded right graft limb was selectively cannulated with a 5-F H1H catheter (Argon, Athens, Tex), and the occlusion was crossed with the catheter and a 0.038-inch Glidewire (manufactured by Terumo, Piscataway, NJ; distributed by Meditech/Boston Scientific, Watertown,
497
498 • Journal of Vascular and Interventional Radiology November 1991
~
~
~
Figure 1. (a) Digital subtraction angiogram of the abdominal aorta obtained from a brachial approach. An end-to-side aorto-biiliac graft originates from the distal aorta. The right limb is occluded proximally. Collaterals reconstitute the iliac bifurcation (not shown). (b) Mer 4 hours of high-dose intraarterial urokinase, the catheter tip is at the proximal end of the occluded graft limb. A tract through the thrombus is present from the initial passage of the catheter; no further clot lysis has occurred. This appearance was unchanged after 23 hours of infusion. (c) Digital subtraction angiogram obtained immediately after graft angioplasty shows irregular filling defects in the graft lumen (Fig 1 continues).
Mass). There was moderate resistance to passage of the catheter along the entire occluded segment, with the greatest resistance at the level of the distal anastomosis. The graft limb was laced with 250,000 U of urokinase (Abbokinase; Abbott Laboratories, North Chicago, Ill), and urokinase was then infused at 240,000 U /h for 2 hours followed by 120,000 U /h for 2 more hours with the catheter at the proximal end of the occlusion. No angiographic change was seen after 4 hours (Fig Ib), so the infusion was continued overnight at 60,000 U/h with the catheter position unchanged. Systemic anticoagulation with intravenously administered heparin to achieve a partial thromboplastin time of one and one-halftimes the controllevel was initiated at the start of thrombolysis and maintained throughout the entire procedure.
After 2.11 million U of intraarterial urokinase was infused over 23 hours, a repeat arteriogram revealed no significant change in the appearance of the occlusion. The referring surgeon believed that operative repair of the graft would be technically difficult and entail a significant risk because of the patient's medical condition, the existing ileal conduit, and the failed synthetic mesh herniorrhaphy, with its concomitant fibrotic reaction, and agreed that percutaneous intervention would be preferable. The right common femoral artery was opacified and punctured under fluoroscopic guidance during injection of contrast material through the brachial catheter. The resting peaksystolic pressure gradient across the occluded graft limb measured 68 mm Hg. A TAD wire (Peripheral Systems Group, Mountain View, Calif) was ma-
nipulated through the channel previously created through the occlusion, and the channel was dilated to 9 F with a Van Andel catheter (Cook, Bloomington, Ind). Endovascular ultrasound (US) was performed with an 8-F, 20MHz transducer (Cardiovascular Imaging Systems, Sunnyvale, Calif). This demonstrated flattening and deformity of the graft with echogenic material filling the graft lumen (Fig 2a). No flow was seen. The occluded segment then was dilated with two inflations of a 9-mm x 4-cm Olbert balloon (MeadoxSurgimed, Stenl~se, Denmark) at 13 atm for 1 minute each. Digitally subtracted arteriograms obtained immediately after dilation revealed a markedly irregular, stenotic lumen containing several large filling defects (Fig lc). A conventional arteriogram obtained a few minutes later demonstrated com-
Soulen et al • 499 Volume 2 Number 4
d. e. £ Figure 1 (continued). (d) Cut-film arteriogram obtained several minutes after graft angioplasty shows reocclusion of the right graft limb. (e, f) Images obtained without (e) and with (f) contrast material from arteriography following tandem placement offour Palmaz stents (between arrows). The right graft limb is now widely patent. Contrast material seen centrally in the pelvis is in the patient's ileal conduit.
plete reocclusion (Fig Id). This was recrossed in a retrograde direction with a TAD wire. Four 8-mm X 3-cm Palmaz stents were balloon expanded in tandem, slightly overlapping each other from the patent proximal portion of the graft limb distally into the proximal external iliac artery (Fig Ie). A final cut-film arteriogram showed excellent flow through the graft lumen after stent placement, with no embolism to the distal vessels. Mter stent placement, the resting peak-systolic pressure gradient across the graft limb decreased to 13 mm Hg from the preprocedural value of 68 mm Hg. Repeat endovascular US demonstrated a dramatic change in the shape of the graft, pulsatile flow, and a thin echogenic layer between the stent struts and the graft (Fig 2b). A small amount of echogenic material appeared to have extruded over a portion of the upper margin of the most proximal
stent, projecting into the lumen (Fig 2c). This material occupied 31 % of the cross-sectional area of the stent lumen (measured by means of pianimetry), equivalent to a 17% diameter stenosis. No defect could be discerned angiographically. We elected not to place an additional stent proximally to cover the region of the sonographic abnormality because (a) a more proximal stent would protrude over the origin of the left graft limb, potentially compromising flow or serving as a site for thrombus formation and embolization, and (b) flow appeared to be brisk and the clinical improvement in the extremity adequate to justify no further intervention, despite the modest residual gradient. Systemic anticoagulation with heparin was resumed after removal of the femoral and brachial catheters and was continued until the following day. Her symptoms resolved completely. The right ankle-brachial index increased to
0.78 from the preprocedural value of 0.54. The reasons for her left leg symptoms and their resolution after the procedure are unclear. Perhaps ischemic symptoms in her right leg led to abnormal weight bearing superimposed on the previously noted neuropathic joint changes in her left hip. The patient suffered mild, transient renal insufficiency after the procedure. Mter discontinuation of heparin, she experienced numbness in her left hand and loss of distal pulses in her left arm. Segmental brachial artery thrombosis at the puncture site with collaterals reconstituting the radial, ulnar, and median arteries was demonstrated angiographically. She was treated conservatively with intravenously administered heparin, and her hand symptoms resolved. Three months after the procedure, she remained asymptomatic and her right ankle-brachial index had increased to 0.93. Eight months after the
500 • Journal of Vascular and Interventional Radiology November 1991
a. b. c. Figure 2. Endovascular sonograms of the thrombosed right graft limb. (a) On the initial image, the graft (curved arrows) is deformed and contracted, probably due to retraction ofthe organized thrombus and lack of flow. Echogenic material fills the entire graft lumen. No flow was seen on real-time images. The transducer (T) appears as a round signal void in the center of the image. The ring of brighter echoes (straight arrow) around the transducer is due to near-field reverberation artifact. (b) Image obtained through the middle of the graft after stent placement shows a widely patent lumen within a ring of bright echoes from the steel stent struts (straight arrow). Note the change in shape of the graft (curved arrows). A thin layer of echogenic material is present between the stent struts and the graft. (c) Image obtained at the upper margin of the proximal stent shows a small amount of echogenic material extruding into the stent lumen (arrow).
procedure she was asymptomatic, ambulating with a walker. Right femoral, dorsalis pedis, and posterior tibial pulses were palpable. Her ankle-brachial index decreased to 0.73. She refused repeat arteriography. Doppler evaluation demonstrated normal velocities of 118 em/sec in the right external iliac artery and 93 em/sec in the right common femoral artery without turbulence. The stented segment could not be visualized sonographically because of overlying bowel. Twelve months after the procedure her clinical status was unchanged. Right femoral, dorsalis pedis, and posterior tibial pulses were palpable. Her ankle-brachial index was 1.0.
DISCUSSION Late occlusion of one limb of aortic bifurcation grafts occurs in 50/0-20% of
patients (4-6). Treatment is usually thrombectomy or femoral-femoral bypass, with correction or bypass of causative outflow lesions as indicated. Replacement of the graft or placement of a new bypass graft from the thorax is necessary in a minority of cases. The secondary patency after a single operative repair is approximately 70% at 1 year and 50% at 5 years, improving to 83% at 1 year and 74% at 5 years with multiple operations for rethrombosis (4-6). Mortality from repeated operation ranges from 1.9% to 9%. It is difficult to assess the morbidity of surgical repair from the available surgical literature, but Ascer et al (7) report a fivefold increase in the prevalence of graft infection after a repeat operation compared to primary bypass procedures. Little data exist on the percutaneous salvage of occluded iliac grafts. McNamara and Bomberger, Durham et al, and Gardiner et al have each reported
small series totaling 30 occluded aortofemoral grafts treated with urokinase followed by angioplasty of underlying lesions (1-3). Technical success for the 30 grafts was 90%, with a 6-month clinical patency rate of 500/0-77% for successfully treated grafts. The reasons given for technical failure of percutaneous methods include the presence of hard, fibrotic thrombus or high-grade stenoses due to intimal hyperplasia (3). The presence of a residual flow-limiting lesion following thrombolysis and angioplasty was the major determinant of early (less than 6 months) reocclusion. Secondary patency is improved if these lesions are corrected surgically. Specific morbidity and mortality figures for thrombolysis of suprainguinal grafts is not available. It is likely that the risk parallels that of regional thrombolytic therapy in general, with reported major morbidity of approximately 10% and mortality of 0.8% (8).
Soulen et al • 501 Volume 2 Number 4
To our knowledge, the use of stents for recanalization of peripheral arterial bypass grafts has not been reported previously. In the case presented, thrombolysis of an occluded aortoiliac graft limb failed despite early recanalization of the lumen with a guide wire and catheter, and lacing of the thrombus with urokinase prior to high-dose thrombolytic therapy. Presumably, this reflected the presence of highly organized thrombus within the graft. Balloon dilation of occluded grafts is problematic, since the nondistensible nature of the synthetic material would seem to make embolization more likely than in a native vessel. Vorwerk and Guenther advocate underdilation of iliac thrombus with a balloon a few millimeters smaller than the normal arterial lumen followed by stent placement to decrease the risk of embolization (9). There were no embolizations in their series of 68 chronic native iliac occlusions treated by means of this method, compared with the 3%-20% prevalence of symptomatic emboli with conventional angioplasty of iliac occlusions. We performed conventional angioplasty with a 9-mm balloon in a 10-mm graft limb. No embolization occurred, but the graft remained occluded. The 8-mm stents compressed the thrombus between the metal struts and the graft, as demonstrated on the endovascular sonogram, creating and maintaining an ample lumen without embolization of the intragraft material. The long-term patency of metal stents in synthetic arterial bypass grafts is unknown. There is one case report of placement ofa Wallstent (Schneider, Minneapolis, Minn) into a composite polytetrafluoroethylene/vein
aortomesenteric graft. The patient was asymptomatic 9 months later (10). Stents have been advocated for treatment of vein grafts and dialysis shunts, which respond poorly to conventional angioplasty, but long-term clinical data are lacking (10,11). In summary, Palmaz balloon-expandable metal stents were used to salvage an occluded aortoiliac graft limb after technical failure of thrombolysis and angioplasty, with an acceptable clinical result and no complications directly related to stent placement. The role of stents in graft salvage remains to be determined. Although most technical failures are due to inability to cross the occluded segment, stents may be helpful in cases in which the lesion is crossed but conventional angioplasty fails. It is conceivable that intravascular stent placement may offer a means to improve the long-term clinical success of revascularization of suprainguinal grafts by eliminating residual flow-limiting lesions (such as hard, chronic thrombus or intimal hyperplasia at anastomotic sites), which do not respond well to conventional angioplasty and are the major determinants of reocclusion. References 1. McNamara TO, Bomberger RA. Factors affecting initial and six month patency rates after intraarterial thrombolysis with high-dose urokinase. Am J Surg 1986; 152:709-712. 2. Durham JD, Geller SC, Abbott WM, et al. Regional infusion of urokinase into occluded lower-extremity bypass grafts: long-term clinical results. Radiology 1989; 172:83-87.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Gardiner GAJr, Harrington DP, Koltun W, Whittemore A, Mannick JA, Levin DC. Salvage of occluded arterial bypass grafts by means of thrombolysis. J Vasc Surg 1989; 9:426-431. Brewster DC, Meier GH III, Darling RC, Moncure AC, LaMuraglia GM, Abbott WM. Reoperation for aortofemoral graft limb occlusion: optimal methods and long-term results. J Vasc Surg 1987; 5:363-374. Bernhard VM, Ray LI, Towne JB. The re-operation of choice for aortofemoral graft occlusion. Surgery 1977; 82:867-874. Crawford ES, Manning LG, Kelly TF. "Redo" surgery after operations for aneurysm and occlusion of the abdominal aorta. Surgery 1977; 81:41-52. Ascer E, Collier P, Gupta SK, Veith FJ. Reoperation for polytetrafluoroethylene bypass failure: the importance of distal outflow site and operative technique in determining outcome. J Vasc Surg 1987; 5:298-310. Gardiner GA Jr, Sullivan KL. Complications of regional thrombolytic therapy. In: Kadir S, ed. Current practice ofinterventional radiology. Philadelphia: BC Decker, 1991; 87-91. Vorwerk D, Guenther RW. Mechanical revascularization of occluded iliac arteries with use of self-expandable endoprostheses. Radiology 1990; 175: 411-415. Zollikofer CL, Largiader I, Bruhlmann WF, Uhlschmid GK, Marty AH. Endovascular stenting of veins and grafts: preliminary clinical experience. Radiology 1988; 167:707-712. Gunther RW, Vorwerk D, BohndorfK, et al. Venous stenoses in dialysis shunts: treatment with self-expanding metallic stents. Radiology 1989; 170: 401-405.
Recanalization of an Occluded Aortoiliac Bypass Graft with Palmaz Stents 1 Michael C. Soulen, MD2 Joseph Bonn, MD Marcelle J. Shapiro, MD
Index terms: Arteries, grafts and prostheses, 98.452, 98.456 • Grafts, interventional procedures, 98.452, 98.456 • Grafts, stenosis or obstruction, 98.452 • Stents JVIR 1991; 2:497-501
Four tandem Palmaz balloon-expandable vascular stents were used to recanalize the completely occluded limb of an aortoiliac bypass graft after failure of thrombolysis and conventional angioplasty. The resting peak-systolic pressure gradient across the occluded limb was reduced from 68 to 13 mm Hg. The patient's rest pain resolved, and the anklebrachial index rose from 0.54 to 0.78. No embolization or stent-related complications occurred. The graft remains patent as determined with noninvasive studies obtained 8 months later. PERCUTANEOUS recanalization of occluded suprainguinal bypass grafts has a technical failure rate of approximately 10% (1-3). We describe salvage of an occluded limb of an aortoiliac bypass graft with Palmaz balloon-expandable stents (Johnson & Johnson Interventional Systems, Warren, NJ) after the failure of recanalization with thrombolysis and conventional angioplasty.
CASE REPORT
1 From the Division of Cardiovascular IInterventional Radiology, Thomas Jefferson University Hospital, 111 S 11th St, Suite 5609 Gibbon Bldg, Philadelphia, PA 19107. Received April 8, 1991; revision requested July 5, revision received August 20, accepted August 26. Address reprint requests to J.B. 2 Current address: Department of Radiology, Hospital of the University ofPennsylvania, Philadelphia.
©
SCVIR, 1991
A 60-year-old woman presented with a 6-month history of recurrent bilateral lower extremity claudication progressing gradually to rest pain. An end-toside Dacron aorto-bi-common-iliac bypass graft had been placed 3 years previously for a distal aortic occlusion, after which she had been asymptomatic. At that time the runoff vessels distal to the graft were normal bilaterally. Her past medical history was significant for hypertension requiring threedrug therapy, obesity, placement of an ileal conduit for a neuropathic bladder secondary to cerebral palsy, and a failed synthetic mesh abdominal herniorrhaphy. She had no history of diabetes, cardiac or cerebrovascular disease, or smoking. On physical examination her legs were pale. No pulses were palpable in the right leg, and only a weak femoral pulse was felt on the left. There was no dependent rubor or skin changes. She ambulated slowly with a walker due to neuromuscular deficits from her
cerebral palsy. Plain radiographs of the pelvis revealed a mild chronic deformity of the left hip. Ankle-brachial indexes were 1.07 on the left and 0.54 on the right. Results of serum laboratory studies were normal except for a mildly elevated creatinine level of 1.6 mg/dL (141 fLmol!L) (normal, < 1.5 mg/dL [133 fLmol!L)). Her subjective complaints of rest pain were out of proportion to her ankle-brachial indexes. It was difficult to determine how much of her pain was due to vascular insufficiency and how much may have been musculoskeletal pain related to her cerebral palsy, but the deterioration of her right anklebrachial index and loss of pulses in the right leg were new, objective findings according to the referring surgeon. Diagnostic arteriography was performed from a distal left brachial artery puncture due to an absent right femoral pulse and a markedly diminished left femoral pulse in this obese patient, leading to a suspicion of bilateral graft disease prior to arteriography. The right limb of the graft was found to be occluded just distal to its origin, with reconstitution of the distal right common iliac artery via collaterals (Fig 1a). The left limb of the graft and the runoff vessels of both lower extremities were patent. The origin of the occluded right graft limb was selectively cannulated with a 5-F H1H catheter (Argon, Athens, Tex), and the occlusion was crossed with the catheter and a 0.038-inch Glidewire (manufactured by Terumo, Piscataway, NJ; distributed by Meditech/Boston Scientific, Watertown,
497
498 • Journal of Vascular and Interventional Radiology November 1991
~
~
~
Figure 1. (a) Digital subtraction angiogram of the abdominal aorta obtained from a brachial approach. An end-to-side aorto-biiliac graft originates from the distal aorta. The right limb is occluded proximally. Collaterals reconstitute the iliac bifurcation (not shown). (b) Mer 4 hours of high-dose intraarterial urokinase, the catheter tip is at the proximal end of the occluded graft limb. A tract through the thrombus is present from the initial passage of the catheter; no further clot lysis has occurred. This appearance was unchanged after 23 hours of infusion. (c) Digital subtraction angiogram obtained immediately after graft angioplasty shows irregular filling defects in the graft lumen (Fig 1 continues).
Mass). There was moderate resistance to passage of the catheter along the entire occluded segment, with the greatest resistance at the level of the distal anastomosis. The graft limb was laced with 250,000 U of urokinase (Abbokinase; Abbott Laboratories, North Chicago, Ill), and urokinase was then infused at 240,000 U /h for 2 hours followed by 120,000 U /h for 2 more hours with the catheter at the proximal end of the occlusion. No angiographic change was seen after 4 hours (Fig Ib), so the infusion was continued overnight at 60,000 U/h with the catheter position unchanged. Systemic anticoagulation with intravenously administered heparin to achieve a partial thromboplastin time of one and one-halftimes the controllevel was initiated at the start of thrombolysis and maintained throughout the entire procedure.
After 2.11 million U of intraarterial urokinase was infused over 23 hours, a repeat arteriogram revealed no significant change in the appearance of the occlusion. The referring surgeon believed that operative repair of the graft would be technically difficult and entail a significant risk because of the patient's medical condition, the existing ileal conduit, and the failed synthetic mesh herniorrhaphy, with its concomitant fibrotic reaction, and agreed that percutaneous intervention would be preferable. The right common femoral artery was opacified and punctured under fluoroscopic guidance during injection of contrast material through the brachial catheter. The resting peaksystolic pressure gradient across the occluded graft limb measured 68 mm Hg. A TAD wire (Peripheral Systems Group, Mountain View, Calif) was ma-
nipulated through the channel previously created through the occlusion, and the channel was dilated to 9 F with a Van Andel catheter (Cook, Bloomington, Ind). Endovascular ultrasound (US) was performed with an 8-F, 20MHz transducer (Cardiovascular Imaging Systems, Sunnyvale, Calif). This demonstrated flattening and deformity of the graft with echogenic material filling the graft lumen (Fig 2a). No flow was seen. The occluded segment then was dilated with two inflations of a 9-mm x 4-cm Olbert balloon (MeadoxSurgimed, Stenl~se, Denmark) at 13 atm for 1 minute each. Digitally subtracted arteriograms obtained immediately after dilation revealed a markedly irregular, stenotic lumen containing several large filling defects (Fig lc). A conventional arteriogram obtained a few minutes later demonstrated com-
Soulen et al • 499 Volume 2 Number 4
d. e. £ Figure 1 (continued). (d) Cut-film arteriogram obtained several minutes after graft angioplasty shows reocclusion of the right graft limb. (e, f) Images obtained without (e) and with (f) contrast material from arteriography following tandem placement offour Palmaz stents (between arrows). The right graft limb is now widely patent. Contrast material seen centrally in the pelvis is in the patient's ileal conduit.
plete reocclusion (Fig Id). This was recrossed in a retrograde direction with a TAD wire. Four 8-mm X 3-cm Palmaz stents were balloon expanded in tandem, slightly overlapping each other from the patent proximal portion of the graft limb distally into the proximal external iliac artery (Fig Ie). A final cut-film arteriogram showed excellent flow through the graft lumen after stent placement, with no embolism to the distal vessels. Mter stent placement, the resting peak-systolic pressure gradient across the graft limb decreased to 13 mm Hg from the preprocedural value of 68 mm Hg. Repeat endovascular US demonstrated a dramatic change in the shape of the graft, pulsatile flow, and a thin echogenic layer between the stent struts and the graft (Fig 2b). A small amount of echogenic material appeared to have extruded over a portion of the upper margin of the most proximal
stent, projecting into the lumen (Fig 2c). This material occupied 31 % of the cross-sectional area of the stent lumen (measured by means of pianimetry), equivalent to a 17% diameter stenosis. No defect could be discerned angiographically. We elected not to place an additional stent proximally to cover the region of the sonographic abnormality because (a) a more proximal stent would protrude over the origin of the left graft limb, potentially compromising flow or serving as a site for thrombus formation and embolization, and (b) flow appeared to be brisk and the clinical improvement in the extremity adequate to justify no further intervention, despite the modest residual gradient. Systemic anticoagulation with heparin was resumed after removal of the femoral and brachial catheters and was continued until the following day. Her symptoms resolved completely. The right ankle-brachial index increased to
0.78 from the preprocedural value of 0.54. The reasons for her left leg symptoms and their resolution after the procedure are unclear. Perhaps ischemic symptoms in her right leg led to abnormal weight bearing superimposed on the previously noted neuropathic joint changes in her left hip. The patient suffered mild, transient renal insufficiency after the procedure. Mter discontinuation of heparin, she experienced numbness in her left hand and loss of distal pulses in her left arm. Segmental brachial artery thrombosis at the puncture site with collaterals reconstituting the radial, ulnar, and median arteries was demonstrated angiographically. She was treated conservatively with intravenously administered heparin, and her hand symptoms resolved. Three months after the procedure, she remained asymptomatic and her right ankle-brachial index had increased to 0.93. Eight months after the
500 • Journal of Vascular and Interventional Radiology November 1991
a. b. c. Figure 2. Endovascular sonograms of the thrombosed right graft limb. (a) On the initial image, the graft (curved arrows) is deformed and contracted, probably due to retraction ofthe organized thrombus and lack of flow. Echogenic material fills the entire graft lumen. No flow was seen on real-time images. The transducer (T) appears as a round signal void in the center of the image. The ring of brighter echoes (straight arrow) around the transducer is due to near-field reverberation artifact. (b) Image obtained through the middle of the graft after stent placement shows a widely patent lumen within a ring of bright echoes from the steel stent struts (straight arrow). Note the change in shape of the graft (curved arrows). A thin layer of echogenic material is present between the stent struts and the graft. (c) Image obtained at the upper margin of the proximal stent shows a small amount of echogenic material extruding into the stent lumen (arrow).
procedure she was asymptomatic, ambulating with a walker. Right femoral, dorsalis pedis, and posterior tibial pulses were palpable. Her ankle-brachial index decreased to 0.73. She refused repeat arteriography. Doppler evaluation demonstrated normal velocities of 118 em/sec in the right external iliac artery and 93 em/sec in the right common femoral artery without turbulence. The stented segment could not be visualized sonographically because of overlying bowel. Twelve months after the procedure her clinical status was unchanged. Right femoral, dorsalis pedis, and posterior tibial pulses were palpable. Her ankle-brachial index was 1.0.
DISCUSSION Late occlusion of one limb of aortic bifurcation grafts occurs in 50/0-20% of
patients (4-6). Treatment is usually thrombectomy or femoral-femoral bypass, with correction or bypass of causative outflow lesions as indicated. Replacement of the graft or placement of a new bypass graft from the thorax is necessary in a minority of cases. The secondary patency after a single operative repair is approximately 70% at 1 year and 50% at 5 years, improving to 83% at 1 year and 74% at 5 years with multiple operations for rethrombosis (4-6). Mortality from repeated operation ranges from 1.9% to 9%. It is difficult to assess the morbidity of surgical repair from the available surgical literature, but Ascer et al (7) report a fivefold increase in the prevalence of graft infection after a repeat operation compared to primary bypass procedures. Little data exist on the percutaneous salvage of occluded iliac grafts. McNamara and Bomberger, Durham et al, and Gardiner et al have each reported
small series totaling 30 occluded aortofemoral grafts treated with urokinase followed by angioplasty of underlying lesions (1-3). Technical success for the 30 grafts was 90%, with a 6-month clinical patency rate of 500/0-77% for successfully treated grafts. The reasons given for technical failure of percutaneous methods include the presence of hard, fibrotic thrombus or high-grade stenoses due to intimal hyperplasia (3). The presence of a residual flow-limiting lesion following thrombolysis and angioplasty was the major determinant of early (less than 6 months) reocclusion. Secondary patency is improved if these lesions are corrected surgically. Specific morbidity and mortality figures for thrombolysis of suprainguinal grafts is not available. It is likely that the risk parallels that of regional thrombolytic therapy in general, with reported major morbidity of approximately 10% and mortality of 0.8% (8).
Soulen et al • 501 Volume 2 Number 4
To our knowledge, the use of stents for recanalization of peripheral arterial bypass grafts has not been reported previously. In the case presented, thrombolysis of an occluded aortoiliac graft limb failed despite early recanalization of the lumen with a guide wire and catheter, and lacing of the thrombus with urokinase prior to high-dose thrombolytic therapy. Presumably, this reflected the presence of highly organized thrombus within the graft. Balloon dilation of occluded grafts is problematic, since the nondistensible nature of the synthetic material would seem to make embolization more likely than in a native vessel. Vorwerk and Guenther advocate underdilation of iliac thrombus with a balloon a few millimeters smaller than the normal arterial lumen followed by stent placement to decrease the risk of embolization (9). There were no embolizations in their series of 68 chronic native iliac occlusions treated by means of this method, compared with the 3%-20% prevalence of symptomatic emboli with conventional angioplasty of iliac occlusions. We performed conventional angioplasty with a 9-mm balloon in a 10-mm graft limb. No embolization occurred, but the graft remained occluded. The 8-mm stents compressed the thrombus between the metal struts and the graft, as demonstrated on the endovascular sonogram, creating and maintaining an ample lumen without embolization of the intragraft material. The long-term patency of metal stents in synthetic arterial bypass grafts is unknown. There is one case report of placement ofa Wallstent (Schneider, Minneapolis, Minn) into a composite polytetrafluoroethylene/vein
aortomesenteric graft. The patient was asymptomatic 9 months later (10). Stents have been advocated for treatment of vein grafts and dialysis shunts, which respond poorly to conventional angioplasty, but long-term clinical data are lacking (10,11). In summary, Palmaz balloon-expandable metal stents were used to salvage an occluded aortoiliac graft limb after technical failure of thrombolysis and angioplasty, with an acceptable clinical result and no complications directly related to stent placement. The role of stents in graft salvage remains to be determined. Although most technical failures are due to inability to cross the occluded segment, stents may be helpful in cases in which the lesion is crossed but conventional angioplasty fails. It is conceivable that intravascular stent placement may offer a means to improve the long-term clinical success of revascularization of suprainguinal grafts by eliminating residual flow-limiting lesions (such as hard, chronic thrombus or intimal hyperplasia at anastomotic sites), which do not respond well to conventional angioplasty and are the major determinants of reocclusion. References 1. McNamara TO, Bomberger RA. Factors affecting initial and six month patency rates after intraarterial thrombolysis with high-dose urokinase. Am J Surg 1986; 152:709-712. 2. Durham JD, Geller SC, Abbott WM, et al. Regional infusion of urokinase into occluded lower-extremity bypass grafts: long-term clinical results. Radiology 1989; 172:83-87.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Gardiner GAJr, Harrington DP, Koltun W, Whittemore A, Mannick JA, Levin DC. Salvage of occluded arterial bypass grafts by means of thrombolysis. J Vasc Surg 1989; 9:426-431. Brewster DC, Meier GH III, Darling RC, Moncure AC, LaMuraglia GM, Abbott WM. Reoperation for aortofemoral graft limb occlusion: optimal methods and long-term results. J Vasc Surg 1987; 5:363-374. Bernhard VM, Ray LI, Towne JB. The re-operation of choice for aortofemoral graft occlusion. Surgery 1977; 82:867-874. Crawford ES, Manning LG, Kelly TF. "Redo" surgery after operations for aneurysm and occlusion of the abdominal aorta. Surgery 1977; 81:41-52. Ascer E, Collier P, Gupta SK, Veith FJ. Reoperation for polytetrafluoroethylene bypass failure: the importance of distal outflow site and operative technique in determining outcome. J Vasc Surg 1987; 5:298-310. Gardiner GA Jr, Sullivan KL. Complications of regional thrombolytic therapy. In: Kadir S, ed. Current practice ofinterventional radiology. Philadelphia: BC Decker, 1991; 87-91. Vorwerk D, Guenther RW. Mechanical revascularization of occluded iliac arteries with use of self-expandable endoprostheses. Radiology 1990; 175: 411-415. Zollikofer CL, Largiader I, Bruhlmann WF, Uhlschmid GK, Marty AH. Endovascular stenting of veins and grafts: preliminary clinical experience. Radiology 1988; 167:707-712. Gunther RW, Vorwerk D, BohndorfK, et al. Venous stenoses in dialysis shunts: treatment with self-expanding metallic stents. Radiology 1989; 170: 401-405.