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Renal Artery Aneurysm Secondary to Fibromuscular Dysplasia in a Young Patient
Renal Artery Aneurysm Secondary to Fibromuscular Dysplasia in a Young Patient Bryce D. Beseth, MD, and William J. Quinones-Baldrich, MD, Los Angeles, California
An 8-year-old male was found on routine physical examination to have a blood pressure of 220/ 110. Renal angiography demonstrated bilateral renal artery stenosis and an aneurysm of the distal left renal artery with branch involvement. At operation, the left renal artery stenosis and aneurysm was repaired by ex vivo arterial reconstruction and autotransplantation of the kidney. Pathologic evaluation of the resected aneurysm confirmed the diagnosis of fibromuscular dysplasia. Fibromuscular dysplasia is the most common cause of renal artery stenosis in children over 1 year of age and can in rare cases be associated with the development of renal artery aneurysms. In complex cases of renal artery stenosis with involvement of renal artery branches, ex vivo repair and orthotopic autotransplantation is an excellent approach for surgical management.
Renal artery stenosis (RAS) is the most common cause of surgically correctable hypertension in children.1 In North America, fibromuscular dysplasia is the most common etiology of pediatric RAS.1-4 Both surgical and endovascular approaches have been described for the treatment of renovascular hypertension (RVH) in children. In recent years, surgical treatment has shifted away from nephrectomy and aortorenal bypass and favored instead direct reimplantation of the renal arteries to the aorta. We report an interesting case of an 8-year-old male with bilateral renal artery stenosis and a left renal artery aneurysm managed with ex vivo repair and orthotopic autotransplantation.
CASE REPORT An 8-year-old Hispanic male presented to his primary care physician for a routine visit and was
Department of Surgery, UCLA School of Medicine, UCLA Medical Center, Los Angeles, CA, USA. Presented at the Twenty-second Annual Meeting of the Southern California Vascular Surgery Society, La Jolla, CA, April 30-May 2, 2004. Correspondence to: William J. Quinones-Baldrich, MD, Department of Surgery, UCLA School of Medicine, 72-167 CHS UCLA Medical Center, Los Angeles, CA 90095, USA, E-mail: [email protected] Ann Vasc Surg 2005; 19: 605-608 DOI: 10.1007/s10016-005-6610-5 Ó Annals of Vascular Surgery Inc. Published online: July 29, 2005
found to have a blood pressure of 220/110. The remainder of the patientÕs physical examination was within normal limits. With the exception of a brief hospitalization at age 4 for presumed viral pneumonia, the patient had an otherwise unremarkable birth, family, and past medical history. The patient reported experiencing occasional headaches but denied any symptoms of fatigability or dyspnea. Laboratory studies demonstrated a creatinine of 0.4 and a normal erythrocyte sedimentation rate (ESR). Further workup included an echocardiogram, which demonstrated mild left ventricular hypertrophy, and a renal ultrasound, which showed normal-sized kidneys. A magnetic resonance (MR) angiogram showed an aneurysm of the left renal artery and probable RAS. Selective renal angiography demonstrated a right segmental RAS, a proximal stenosis of the left renal artery, and aneurysmal dilation of the distal left renal artery involving multiple branches (Fig. 1). The patient was then referred to our institution for further management. The patient was taken to the operating room, and the left kidney was explored via a retroperitoneal approach. The aneurysm was found to involve half of the circumference of the artery, and three branch vessels were observed to be arising from it. We elected to perform an ex vivo renal artery repair. The left kidney was completely mobilized, and the renal artery and renal vein were transected. After perfusion with cold lactated
605
606 Beseth and Quinones-Baldrich
Annals of Vascular Surgery
Fig. 1. A Aortogram with bilateral nephrograms. B Selective right renal angiogram. C Selective left renal angiogram.
RingerÕs solution containing 1 unit of heparin/cc, the kidney was placed in slushed iced saline (Fig. 2). The patient received systemic heparin. The aneurysm was resected, and the renal artery and two of its branches were repaired with autogenous saphenous vein. The upper polar branch required reimplantation on the vein patch used to repair the artery. After reconstruction of the branch vessels, the renal artery was sewn end-to-side to the aorta and renal vein anastomosis was performed in an end-to-end manner. The kidney was then replaced in its orthotopic position. The patient had an uncomplicated postoperative course with normal creatinine. Pathologic evaluation of the resected aneurysm demonstrated fibrosis of the media as well as intimal fibromuscular hyperplasia most consistent with fibromuscular dysplasia, medial type. Three months after surgery, renal scintigraphy demonstrated normal renal flow to the left kidney. The patientÕs hypertension is markedly improved, although he still requires medication for blood pressure control. Intervention for correction of the patientÕs right renal artery branch stenosis is planned in the near future.
DISCUSSION RVH is the most common cause of surgically correctable hypertension in children. Although hypertension in children can result in neurologic symptoms and congestive heart failure, many patients are asymptomatic. Even in asymptomatic
patients, however, echocardiography frequently discloses evidence of left ventricular hypertrophy.4 In North America and Western Europe, fibromuscular dysplasia is the most common etiology of pediatric RVH, whereas in Asia and Africa, aortoarteritis is the most common cause.5 The fibromuscular dysplasia that is observed in the pediatric population does not demonstrate the classic ‘‘string of beads’’ pattern seen in adults. Instead, the stenoses generally appear as discrete narrowings on angiography. The focal medial hyperplasia with associated intimal fibromuscular hyperplasia found on pathologic examination in our patient is typical of that observed in other series.3,4 A variety of noninvasive modalities have been investigated for the diagnosis of RVH in children, including captopril renal scintigraphy, computed tomographic (CT) angiography, and MR angiography.6-8 At this time, however, contrast angiography remains the gold standard for evaluation of RAS because of its superior sensitivity and specificity and the greater detail it provides for planning complex reconstructions. Over the past 30 years, the operative strategy for surgical treatment of RAS in children has changed significantly. Nephrectomy, while frequent in the past, is now rarely performed. In current practice, renal autotransplantation is the surgical treatment of choice for pediatric RAS.2,4 When aortorenal bypass must be performed, autogenous arterial grafts or reinforced vein grafts are used preferentially instead of vein bypass.3,9 Stanley et al.4 reported marked aneurysmal dilation in 11 of 31 vein
Vol. 19, No. 5, 2005
Renal artery aneurysm and fibromuscular dysplasia 607
Fig. 2. A Perfusion of the left kidney with heparinized lactated RingerÕs, demonstrating the main renal artery stenosis and distal aneurysm with branch involvement. B Reimplantation of repaired artery to aorta and renal vein end-to-end anastomosis.
grafts used for aortorenal bypass, necessitating revision and plication in three patients and nephrectomy in two patients following microembolization to the kidney. When autogenous arterial grafts are unavailable, vein grafts may be reinforced by placing them within a tube of DacronTM mesh. These reinforced vein grafts do not become aneurysmal, unlike unsupported vein grafts.9 Although there is a theoretical risk of future aneurysmal dilation at the site of the vein patch angioplasty described in this case, degeneration of renal vein patch angioplasties has not been described in the pediatric literature. Repair with autogenous hypogastric artery is an alternative approach, but harvest of the hypogastric artery is complicated by the long-term potential for sexual dysfunction. Recently, the use of radial artery as a conduit for distal renal artery reconstruction has been reported in adults, but this has not been reported in the pediatric population.10 Following surgery for RAS, 9698% of children will experience a reduction in blood pressure and 70-79% of patients will have a normal blood pressure without medication.2-4 However, up to 24% of patients will require a secondary procedure to treat complications such as graft thrombosis, aneurysmal dilation of vein grafts, and continued hypertension caused by unsuccessfully revascularized kidneys.
There has been increasing interest in endovascular treatment of RVH in children. Angioplasty has been reported to improve hypertension in 6794% of children with RAS and to cure 34-94% of patients.5,11-13 When evaluating these results, it is important to note that the duration of follow-up in most series reporting angioplasty for treatment of RAS is much shorter than that in surgical series. This makes a comparison between long-term success rates of angioplasty and surgery difficult. Restenosis following angioplasty for fibromuscular dysplasia in adults has been found in 23% of patients at 1 year.14 In a series of hypertensive pediatric patients treated with angioplasty for RAS due to aortoarteritis and fibromuscular dysplasia, a similar restenosis rate of 25.8% was observed at 41 months.5 The success of angioplasty for treatment of RAS is highly dependent on the morphology of the renal artery lesion. The best results are obtained in the treatment of short, discrete lesions located in the middle or distal part of the renal artery. Lower success rates are seen with angioplasty of long ostial stenoses or multiple stenoses.12,13 Furthermore, some lesions that appear as discrete stenoses on angiography may actually represent arterial hypoplasia and are therefore not amenable to percutaneous intervention. Additionally, failed angioplasty
608 Beseth and Quinones-Baldrich
can make subsequent surgical repair more difficult. This underscores the importance of patient selection in determining which patients should be treated with angioplasty and which patients should go directly to surgery. In the case presented here, the left renal artery clearly required operative repair. Angioplasty could have been attempted for dilation of the RAS, but there is currently no effective endovascular approach for treatment of a renal artery aneurysm involving the segmental renal arteries. Following left renal artery repair, the patient still requires medication for treatment of hypertension due to his uncorrected right segmental RAS. Because it is a discrete focal stenosis, this lesion could be considered for angioplasty, but its proximity to the right renal artery branch point may make angioplasty in this area difficult. We plan to reevaluate the patient with selective angiography to help decide whether to proceed with angioplasty or with open surgical repair. Surgery was for many years the standard therapy for treatment of RVH in children. The surgical approach to RVH has evolved away from nephrectomy and aortorenal vein bypass to the use of autogenous arterial grafts and ideally autotransplantation following renal artery repair. Although the success rates reported in some angioplasty series are comparable to those achieved with surgery, the length of follow-up in these series is significantly shorter. Angioplasty may have a role in the treatment of carefully selected patients whose renal artery lesions appear favorable on angiography; however, for multiple stenoses and complex lesions, surgical therapy, in particular renal autotransplantation, remains the most effective treatment.
Annals of Vascular Surgery
REFERENCES 1. Hiner LB, Falkner B. Renovascular hypertension in children. Pediatr Clin North Am 1993;1:123-140. 2. Martinez A, Novick AC, Cunningham R, Goormastic M. Improved results of vascular reconstruction in pediatric and young adult patients with renovascular hypertension. J Urol 1990;3:717-720. 3. OÕNeill JA, Jr. Long-term outcome with surgical treatment of renovascular hypertension. J Pediatr Surg 1998;1:106-111. 4. Stanley JC, Zelenock GB, Messina LM, Wakefield TW. Pediatric renovascular hypertension: a thirty-year experience of operative treatment. J Vasc Surg 1995;2:212-226. 5. Tyagi S, Kaul UA, Satsangi DK, Arora R. Percutaneous transluminal angioplasty for renovascular hypertension in children: initial and long-term results. Pediatrics 1997;1:44-49. 6. Bosmans JL, De Broe ME. Renovascular hypertension: diagnostic and therapeutic challenges. JBR-BTR 2004;1:32-35. 7. Lagomarsino E, Orellana P, Munoz J, Velasquez C, Cavagnaro F, Valdes F. Captopril scintigraphy in the study of arterial hypertension in pediatrics. Pediatr Nephrol 2004;1:66-70. 8. Vade A, Agrawal R, Lim-Dunham J, Hartoin D. Utility of computed tomographic renal angiogram in the management of childhood hypertension. Pediatr Nephrol 2002;9:741-747. 9. Berkowitz HD, OÕNeill JA, Jr. Renovascular hypertension in children. Surgical repair with special reference to the use of reinforced vein grafts. J Vasc Surg 1989;1:46-55. 10. Patterson RB, Smail D. Radial artery as conduit for distal renal artery reconstruction. J Vasc Surg 2003;3:609-612. 11. Casalini E, Sfondrini MS, Fossali E. Two-year clinical followup of children and adolescents after percutaneous transluminal angioplasty for renovascular hypertension. Invest Radiol 1995;1:40-43. 12. Courtel JV, Soto B, Niaudet P, Gagnadoux MF, Carteret M, Quignodon JF, Brunelle F. Percutaneous transluminal angioplasty of renal artery stenosis in children. Pediatr Radiol 1998;1:59-63. 13. Mali WP, Puijlaert CB, Kouwenberg HJ, et al. Percutaneous transluminal renal angioplasty in children and adolescents. Radiology 1987;2:391-394. 14. Birrer M, Do DD, Mahler F, Triller J, Baumgartner I. Treatment of renal artery fibromuscular dysplasia with balloon angioplasty: a prospective follow-up study. Eur J Vasc Endovasc Surg 2002;2:146-152.
An 8-year-old male was found on routine physical examination to have a blood pressure of 220/ 110. Renal angiography demonstrated bilateral renal artery stenosis and an aneurysm of the distal left renal artery with branch involvement. At operation, the left renal artery stenosis and aneurysm was repaired by ex vivo arterial reconstruction and autotransplantation of the kidney. Pathologic evaluation of the resected aneurysm confirmed the diagnosis of fibromuscular dysplasia. Fibromuscular dysplasia is the most common cause of renal artery stenosis in children over 1 year of age and can in rare cases be associated with the development of renal artery aneurysms. In complex cases of renal artery stenosis with involvement of renal artery branches, ex vivo repair and orthotopic autotransplantation is an excellent approach for surgical management.
Renal artery stenosis (RAS) is the most common cause of surgically correctable hypertension in children.1 In North America, fibromuscular dysplasia is the most common etiology of pediatric RAS.1-4 Both surgical and endovascular approaches have been described for the treatment of renovascular hypertension (RVH) in children. In recent years, surgical treatment has shifted away from nephrectomy and aortorenal bypass and favored instead direct reimplantation of the renal arteries to the aorta. We report an interesting case of an 8-year-old male with bilateral renal artery stenosis and a left renal artery aneurysm managed with ex vivo repair and orthotopic autotransplantation.
CASE REPORT An 8-year-old Hispanic male presented to his primary care physician for a routine visit and was
Department of Surgery, UCLA School of Medicine, UCLA Medical Center, Los Angeles, CA, USA. Presented at the Twenty-second Annual Meeting of the Southern California Vascular Surgery Society, La Jolla, CA, April 30-May 2, 2004. Correspondence to: William J. Quinones-Baldrich, MD, Department of Surgery, UCLA School of Medicine, 72-167 CHS UCLA Medical Center, Los Angeles, CA 90095, USA, E-mail: [email protected] Ann Vasc Surg 2005; 19: 605-608 DOI: 10.1007/s10016-005-6610-5 Ó Annals of Vascular Surgery Inc. Published online: July 29, 2005
found to have a blood pressure of 220/110. The remainder of the patientÕs physical examination was within normal limits. With the exception of a brief hospitalization at age 4 for presumed viral pneumonia, the patient had an otherwise unremarkable birth, family, and past medical history. The patient reported experiencing occasional headaches but denied any symptoms of fatigability or dyspnea. Laboratory studies demonstrated a creatinine of 0.4 and a normal erythrocyte sedimentation rate (ESR). Further workup included an echocardiogram, which demonstrated mild left ventricular hypertrophy, and a renal ultrasound, which showed normal-sized kidneys. A magnetic resonance (MR) angiogram showed an aneurysm of the left renal artery and probable RAS. Selective renal angiography demonstrated a right segmental RAS, a proximal stenosis of the left renal artery, and aneurysmal dilation of the distal left renal artery involving multiple branches (Fig. 1). The patient was then referred to our institution for further management. The patient was taken to the operating room, and the left kidney was explored via a retroperitoneal approach. The aneurysm was found to involve half of the circumference of the artery, and three branch vessels were observed to be arising from it. We elected to perform an ex vivo renal artery repair. The left kidney was completely mobilized, and the renal artery and renal vein were transected. After perfusion with cold lactated
605
606 Beseth and Quinones-Baldrich
Annals of Vascular Surgery
Fig. 1. A Aortogram with bilateral nephrograms. B Selective right renal angiogram. C Selective left renal angiogram.
RingerÕs solution containing 1 unit of heparin/cc, the kidney was placed in slushed iced saline (Fig. 2). The patient received systemic heparin. The aneurysm was resected, and the renal artery and two of its branches were repaired with autogenous saphenous vein. The upper polar branch required reimplantation on the vein patch used to repair the artery. After reconstruction of the branch vessels, the renal artery was sewn end-to-side to the aorta and renal vein anastomosis was performed in an end-to-end manner. The kidney was then replaced in its orthotopic position. The patient had an uncomplicated postoperative course with normal creatinine. Pathologic evaluation of the resected aneurysm demonstrated fibrosis of the media as well as intimal fibromuscular hyperplasia most consistent with fibromuscular dysplasia, medial type. Three months after surgery, renal scintigraphy demonstrated normal renal flow to the left kidney. The patientÕs hypertension is markedly improved, although he still requires medication for blood pressure control. Intervention for correction of the patientÕs right renal artery branch stenosis is planned in the near future.
DISCUSSION RVH is the most common cause of surgically correctable hypertension in children. Although hypertension in children can result in neurologic symptoms and congestive heart failure, many patients are asymptomatic. Even in asymptomatic
patients, however, echocardiography frequently discloses evidence of left ventricular hypertrophy.4 In North America and Western Europe, fibromuscular dysplasia is the most common etiology of pediatric RVH, whereas in Asia and Africa, aortoarteritis is the most common cause.5 The fibromuscular dysplasia that is observed in the pediatric population does not demonstrate the classic ‘‘string of beads’’ pattern seen in adults. Instead, the stenoses generally appear as discrete narrowings on angiography. The focal medial hyperplasia with associated intimal fibromuscular hyperplasia found on pathologic examination in our patient is typical of that observed in other series.3,4 A variety of noninvasive modalities have been investigated for the diagnosis of RVH in children, including captopril renal scintigraphy, computed tomographic (CT) angiography, and MR angiography.6-8 At this time, however, contrast angiography remains the gold standard for evaluation of RAS because of its superior sensitivity and specificity and the greater detail it provides for planning complex reconstructions. Over the past 30 years, the operative strategy for surgical treatment of RAS in children has changed significantly. Nephrectomy, while frequent in the past, is now rarely performed. In current practice, renal autotransplantation is the surgical treatment of choice for pediatric RAS.2,4 When aortorenal bypass must be performed, autogenous arterial grafts or reinforced vein grafts are used preferentially instead of vein bypass.3,9 Stanley et al.4 reported marked aneurysmal dilation in 11 of 31 vein
Vol. 19, No. 5, 2005
Renal artery aneurysm and fibromuscular dysplasia 607
Fig. 2. A Perfusion of the left kidney with heparinized lactated RingerÕs, demonstrating the main renal artery stenosis and distal aneurysm with branch involvement. B Reimplantation of repaired artery to aorta and renal vein end-to-end anastomosis.
grafts used for aortorenal bypass, necessitating revision and plication in three patients and nephrectomy in two patients following microembolization to the kidney. When autogenous arterial grafts are unavailable, vein grafts may be reinforced by placing them within a tube of DacronTM mesh. These reinforced vein grafts do not become aneurysmal, unlike unsupported vein grafts.9 Although there is a theoretical risk of future aneurysmal dilation at the site of the vein patch angioplasty described in this case, degeneration of renal vein patch angioplasties has not been described in the pediatric literature. Repair with autogenous hypogastric artery is an alternative approach, but harvest of the hypogastric artery is complicated by the long-term potential for sexual dysfunction. Recently, the use of radial artery as a conduit for distal renal artery reconstruction has been reported in adults, but this has not been reported in the pediatric population.10 Following surgery for RAS, 9698% of children will experience a reduction in blood pressure and 70-79% of patients will have a normal blood pressure without medication.2-4 However, up to 24% of patients will require a secondary procedure to treat complications such as graft thrombosis, aneurysmal dilation of vein grafts, and continued hypertension caused by unsuccessfully revascularized kidneys.
There has been increasing interest in endovascular treatment of RVH in children. Angioplasty has been reported to improve hypertension in 6794% of children with RAS and to cure 34-94% of patients.5,11-13 When evaluating these results, it is important to note that the duration of follow-up in most series reporting angioplasty for treatment of RAS is much shorter than that in surgical series. This makes a comparison between long-term success rates of angioplasty and surgery difficult. Restenosis following angioplasty for fibromuscular dysplasia in adults has been found in 23% of patients at 1 year.14 In a series of hypertensive pediatric patients treated with angioplasty for RAS due to aortoarteritis and fibromuscular dysplasia, a similar restenosis rate of 25.8% was observed at 41 months.5 The success of angioplasty for treatment of RAS is highly dependent on the morphology of the renal artery lesion. The best results are obtained in the treatment of short, discrete lesions located in the middle or distal part of the renal artery. Lower success rates are seen with angioplasty of long ostial stenoses or multiple stenoses.12,13 Furthermore, some lesions that appear as discrete stenoses on angiography may actually represent arterial hypoplasia and are therefore not amenable to percutaneous intervention. Additionally, failed angioplasty
608 Beseth and Quinones-Baldrich
can make subsequent surgical repair more difficult. This underscores the importance of patient selection in determining which patients should be treated with angioplasty and which patients should go directly to surgery. In the case presented here, the left renal artery clearly required operative repair. Angioplasty could have been attempted for dilation of the RAS, but there is currently no effective endovascular approach for treatment of a renal artery aneurysm involving the segmental renal arteries. Following left renal artery repair, the patient still requires medication for treatment of hypertension due to his uncorrected right segmental RAS. Because it is a discrete focal stenosis, this lesion could be considered for angioplasty, but its proximity to the right renal artery branch point may make angioplasty in this area difficult. We plan to reevaluate the patient with selective angiography to help decide whether to proceed with angioplasty or with open surgical repair. Surgery was for many years the standard therapy for treatment of RVH in children. The surgical approach to RVH has evolved away from nephrectomy and aortorenal vein bypass to the use of autogenous arterial grafts and ideally autotransplantation following renal artery repair. Although the success rates reported in some angioplasty series are comparable to those achieved with surgery, the length of follow-up in these series is significantly shorter. Angioplasty may have a role in the treatment of carefully selected patients whose renal artery lesions appear favorable on angiography; however, for multiple stenoses and complex lesions, surgical therapy, in particular renal autotransplantation, remains the most effective treatment.
Annals of Vascular Surgery
REFERENCES 1. Hiner LB, Falkner B. Renovascular hypertension in children. Pediatr Clin North Am 1993;1:123-140. 2. Martinez A, Novick AC, Cunningham R, Goormastic M. Improved results of vascular reconstruction in pediatric and young adult patients with renovascular hypertension. J Urol 1990;3:717-720. 3. OÕNeill JA, Jr. Long-term outcome with surgical treatment of renovascular hypertension. J Pediatr Surg 1998;1:106-111. 4. Stanley JC, Zelenock GB, Messina LM, Wakefield TW. Pediatric renovascular hypertension: a thirty-year experience of operative treatment. J Vasc Surg 1995;2:212-226. 5. Tyagi S, Kaul UA, Satsangi DK, Arora R. Percutaneous transluminal angioplasty for renovascular hypertension in children: initial and long-term results. Pediatrics 1997;1:44-49. 6. Bosmans JL, De Broe ME. Renovascular hypertension: diagnostic and therapeutic challenges. JBR-BTR 2004;1:32-35. 7. Lagomarsino E, Orellana P, Munoz J, Velasquez C, Cavagnaro F, Valdes F. Captopril scintigraphy in the study of arterial hypertension in pediatrics. Pediatr Nephrol 2004;1:66-70. 8. Vade A, Agrawal R, Lim-Dunham J, Hartoin D. Utility of computed tomographic renal angiogram in the management of childhood hypertension. Pediatr Nephrol 2002;9:741-747. 9. Berkowitz HD, OÕNeill JA, Jr. Renovascular hypertension in children. Surgical repair with special reference to the use of reinforced vein grafts. J Vasc Surg 1989;1:46-55. 10. Patterson RB, Smail D. Radial artery as conduit for distal renal artery reconstruction. J Vasc Surg 2003;3:609-612. 11. Casalini E, Sfondrini MS, Fossali E. Two-year clinical followup of children and adolescents after percutaneous transluminal angioplasty for renovascular hypertension. Invest Radiol 1995;1:40-43. 12. Courtel JV, Soto B, Niaudet P, Gagnadoux MF, Carteret M, Quignodon JF, Brunelle F. Percutaneous transluminal angioplasty of renal artery stenosis in children. Pediatr Radiol 1998;1:59-63. 13. Mali WP, Puijlaert CB, Kouwenberg HJ, et al. Percutaneous transluminal renal angioplasty in children and adolescents. Radiology 1987;2:391-394. 14. Birrer M, Do DD, Mahler F, Triller J, Baumgartner I. Treatment of renal artery fibromuscular dysplasia with balloon angioplasty: a prospective follow-up study. Eur J Vasc Endovasc Surg 2002;2:146-152.