Vascular stents and development of endoluminal therapy of aortic aneurysm

Intravascular stents have played an important role in improving early and long-term patency in the treatment of arterial occlusive disease, particularly in the iliac arteries after failed balloon angioplasty. The development of covered stents opened a new dimension for non-operative therapy of aneurysmal disease. Transluminally placed stent-grafts represent a blending of technologies with use of intravascular stents and prosthetic vascular grafts. Stent-graft combinations were first envisioned by Dotter in 1969 as devices that would ultimately be useful to treat aneurysms, pseudoaneurysms and arterio-venous fistulas. Animal studies of endovascular stented grafts demonstrated the potential feasibility of these devices to treat arterial lesions. Parodi et al. first implanted stent-grafts in patients with abdominal aortic aneurysms and demonstrated its clinical feasibility. Newly developed stent-grafts allowed to treat successfully a limited number of patients with AAA. Although much has been reported about the healing properties of prosthetic grafts in extraluminal locations, there are only little data concerning the arterial response to a prosthetic graft placed within the lumen or anchored into the wall of a human vessel. Therefore, long-term evaluation of these new devices will be crucial.     

Endovascular grafts for noninfected aortoiliac anastomotic aneurysms

PURPOSE: This report describes our experience with endovascular repair of aortic and iliac anastomotic aneurysms. METHODS: Between June 1994 and March 1996, 12 noninfected aortic or iliac anastomotic aneurysms in 10 patients who had serious comorbid medical conditions that precluded or made difficult standard operative repair were treated using endovascular grafts. No patient in this study had a history of fever, leukocytosis, or computed tomographic evidence of a periprosthetic fluid collection that was suggestive of infection of the original graft. Endovascular grafts composed of polytetrafluoroethylene and balloon-expandable stents were introduced through a femoral arteriotomy and were placed using over-the-wire techniques under C-arm fluoroscopic guidance. RESULTS: Endovascular grafts were successfully inserted in all patients with aortic or iliac anastomotic aneurysms. There were no procedure-related deaths, and complications included one postprocedure wound hematoma and one perioperative myocardial infarction. Graft patency has been maintained for a mean of 16.1 months, with no computed tomographic evidence of aneurysmal enlargement or perigraft leakage. CONCLUSIONS: Endovascular grafts appear to be a safe and effective technique for excluding some noninfected aortoiliac anastomotic aneurysms in high-risk patients and may become a treatment option in all patients who have clinically significant lesions.     

Endoleaks after endovascular graft treatment of aortic aneurysms: classification, risk factors, and outcome

PURPOSE: Incomplete endovascular graft exclusion of an abdominal aortic aneurysm results in an endoleak. To better understand the pathogenesis, significance, and fate of endoleaks, we analyzed our experience with endovascular aneurysm repair. METHODS: Between November 1992 and May 1997, 47 aneurysms were treated. In a phase I study, patients received either an endovascular aortoaortic graft (11) or an aortoiliac, femorofemoral graft (8). In phase II, procedures and grafts were modified to include aortofemoral, femorofemoral grafts (28) that were inserted with juxtarenal proximal stents, sutured endovascular distal anastomoses within the femoral artery, and hypogastric artery coil embolization. Endoleaks were detected by arteriogram, computed tomographic scan, or duplex ultrasound. Classification systems to describe anatomic, chronologic, and physiologic endoleak features were developed, and aortic characteristics were correlated with endoleak incidence. RESULTS: Endoleaks were discovered in 11 phase I patients (58%) and only six phase II patients (21%; p < 0.05). Aneurysm neck lengths 2 cm or less increased the incidence of endoleaks (p < 0.05). Although not significant, aneurysms with patent side branches or severe neck calcification had a higher rate of endoleaks than those without these features (47% vs 29% and 57% vs 33%, respectively), and patients with iliac artery occlusive disease had a lower rate of endoleaks than those without occlusive disease (18% vs 42%). Endoleak classifications revealed that most endoleaks were immediate, without outflow, and persistent (71% each), proximal (59%), and had aortic inflow (88%). One patient with a persistent endoleak had aneurysm rupture and died. CONCLUSIONS: Endoleaks complicate a significant number of endovascular abdominal aortic aneurysm repairs and may permit aneurysm growth and rupture. The type of graft used, the technique of graft insertion, and aortic anatomic features all affect the rate of endoleaks. Anatomic, chronologic, and physiologic classifications can facilitate endoleak reporting and improve understanding of their pathogenesis, significance, and fate.     

Aortoiliac stent deployment versus surgical reconstruction: analysis of outcome and cost

PURPOSE: The purpose of this study is to compare complication rate, primary patency, and cost of stent deployment with direct surgical reconstruction for the treatment of severe aortoiliac occlusive disease. METHODS: From March 1, 1992, to May 31, 1996, 119 patients receiving treatment for aortoiliac occlusive disease were analyzed after exclusions. Sixty-five patients had stent deployment and 54 patients had surgical reconstruction. Data were evaluated within and between the groups by univariate and multivariate logistic regression, life-table, t-test, and cross tabulation with chi2 analysis. RESULTS: There was no significant difference between the groups with regard to demographic features or presenting symptoms (all p values > 0.07). Incidence of procedure-related complications was similar (p = 0.30). However, there were more systemic complications in the surgery group (15 versus 2; RR = 5.5, p < 0.01) and more vascular complications in the stent group (16 versus 3; RR = 12, p < 0.002). Incidence and type of late complications were not appreciably different (all p values > 0.05). Cumulative primary patency rate of bypass grafts was significantly better than stented iliac arteries at 18 months (93% versus 77%), 30 months (93% versus 68%) and 42 months (93% versus 68%); p = 0.002, log rank. Multivariate analysis identified female gender (RR = 4.6, p = 0.03), ipsilateral SFA occlusion (RR = 5.6, p = 0.01), procedure-related vascular complication (RR = 9.7, p = 0.002), and hypercholesterolemia (RR = 5.0, p = 0.02) as independent predictors of bypass graft or stent thrombosis. Mean total hospital cost per limb treated did not differ significantly between surgery and stent deployment groups ($9383 versus $8626, respectively; p = 0.66, t-test). CONCLUSIONS: Treatment of severe aortoiliac occlusive disease by surgical reconstruction or stent deployment has a similar complication rate. Mean hospital cost per limb treated is essentially equal. However, cumulative primary patency rate of bypass grafts is superior to stents. Therefore, considering the elements of cost and patency, surgical revascularization has greater value. The benchmark for cost-effective treatment of severe aortoiliac occlusive disease is direct surgical reconstruction.     

Transfemoral endovascular aortic graft placement

PURPOSE: The purpose of this study was to develop an endovascular system for transfemoral placement of straight aortic grafts and bifurcated aortoiliac grafts. METHODS: Both types of graft consist of barbed, self-expanding stents attached to a woven polyester fabric. Survival studies of straight-graft function were performed in six large mongrel dogs. Digital subtraction fluoroscopic equipment was used to guide insertion and record angiograms at 0, 1, and 3 months. Bifurcated grafts were inserted in an additional eight dogs, four with distal stents and four without. Straight grafts were inserted into six cadaveric aortas (five atherosclerotic and one aneurysmal; age 68.7 + 5.7 years) to assess stent attachment. RESULTS: Angiograms obtained immediately after straight-graft insertion showed placement to be within 4.6 + 1.6 mm of the intended level. Follow-up angiograms at 1 and 3 months showed no migration, no leakage, and patency of all six grafts. After bifurcated graft insertion there were no angiographic signs of perigraft leakage, with or without distal stents. The mean force required to displace straight grafts 10 mm from their original position in cadaveric aortas was 1388 + 127 g. CONCLUSION: These preliminary results show that straight and bifurcated endovascular grafts can be positioned accurately and securely in the abdominal aorta.     

Initial experience with endovascular aneurysm repair: comparison of early results with outcome of conventional open repair

PURPOSE: To determine the safety, effectiveness, and problems encountered with endovascular repair of abdominal aortic aneurysm (AAA). Initial experience with endoluminal stent grafts was examined and compared with outcome for a matched concurrent control group undergoing conventional operative repair of AAA. METHODS: Over a 3-year period, 30 patients underwent attempts at endovascular repair of infrarenal AAA. Of the 28 (93%) successfully implanted endografts, 8 were tube endografts, 8 bifurcated grafts, and 12 aortouniiliac grafts combined with femorofemoral bypass. Most of the procedures were performed in the past year because the availability of bifurcated and aortoiliac endografts markedly expanded the percentage of patients with AAA who might be treated with endoluminal methods. The follow-up period ranged from 1 to 44 months, with a mean value of 11 months. RESULTS: Endovascular procedures demonstrated significant advantages with respect to reduced blood loss (408 versus 1287 ml), use of an intensive care unit (0.1 versus 1.75 days), length of hospitalization (3.9 versus 10.3 days), and quicker recovery (11 versus 47 days). Although the total number of postoperative complications was identical for the two groups, the nature of the complications differed considerably. Local and vascular complications characteristic of endovascular repair could frequently be corrected at the time of the procedure and tended to be less severe than systemic or remote complications, which predominated among the open surgical repair group. On an intent-to-treat basis, 23 (77%) of the 30 AAAs were successfully managed with endoluminal repair. The seven (23%) failures were attributable to two immediate conversions caused by access problems, three persistent endoleaks, one late conversion caused by AAA expansion, and one late rupture. CONCLUSIONS: Although less definitive than those for conventional operations, these early results suggest that endovascular AAA repair offers considerable benefits for appropriate patients. The results justify continued application of this method of AAA repair, particularly in the treatment of older persons at high risk.     

Patient tolerance of craniotomy performed with the patient under local anesthesia and monitored conscious sedation

PURPOSE: To determine whether preoperative aortoiliac arteriography can be replaced with noninvasive evaluation in the management of some patients with chronic lower extremity ischemia. METHODS: Preoperative evaluation was performed on 184 ischemic limbs (119 patients) over 19 months by means of aortoiliac arteriography with runoff and noninvasive studies, which included common femoral artery duplex scanning, waveform and acceleration time (normal <140 msec), and aortoiliac duplex scanning. An algorithm was proposed for combining indirect (common femoral artery evaluation) and direct (aortoiliac evaluation) noninvasive studies to decrease the need for aortoiliac arteriography when possible. RESULTS: Aortoiliac occlusive disease (> or =50% stenosis to occlusion) was present at arteriography in 48 limbs (30%), and there was no inflow disease in 114 (70%). Aortoiliac lesions were identified by means of noninvasive studies. The accuracies of femoral waveform, acceleration time, and aortoiliac duplex studies were 85%, 89% and 87%. The negative predictive values were 92%, 94% and 100%. The acceleration time results were not affected by runoff status but were significantly different for various categories of stenosis (p < 0.05). The algorithm was applied to the data obtained. When acceleration time and waveform were normal, 84 of 86 patients (98%) had no stenosis at arteriography. When aortoiliac duplex findings were normal, the arteriographic findings were normal in all examinations. CONCLUSION: A combination of indirect and direct noninvasive studies can be used reliably to rule out clinically significant inflow occlusive disease and allows selective use of aortoiliac arteriography in patients with lower extremity ischemia.     

Three-year experience with the White-Yu Endovascular GAD Graft for transluminal repair of aortic and iliac aneurysms

PURPOSE: To report a > 3-year experience with a modular, balloon-expandable endovascular graft used for aneurysm exclusion in the aorta and other arteries. METHODS: The customized White-Yu Endovascular GAD Graft, a woven polyester prosthesis with an intrinsic Elgiloy wire graft attachment system along the body of the graft, is a flexible endograft design available in straight, tapered, and bifurcated versions that can be delivered transluminally through 18F to 24F sheaths. RESULTS: Since July 1993, 93 patients have received the White-Yu endograft for treatment of 76 abdominal aortic, 3 thoracic aortic, 13 iliac, and 1 popliteal aneurysms. Of the 79 aortic procedures, 39 involved straight tube grafts, 20 were tapered aortoiliac models, and 20 were bifurcated devices. Success rates for tube grafts were 81% in the abdominal aorta and 100% for the thoracic aorta; 5 primary endoleaks (14%) and 2 conversions to surgery (5.6%) occurred with this graft type. Aortoiliac grafts were deployed successfully in 95% (19/20) of cases with 1 conversion (5%) due to thrombosis. Seventy-five percent of the bifurcated endograft procedures were successful, with 4 conversions (20%) for technical failures and 1 graft thrombosis. Four additional endografts were deployed to treat two primary and two secondary endoleaks in tube graft patients. Two access-related arterial injuries were treated surgically. There was one case of embolus to the distal femoral artery but no microembolization. Overall perioperative (30-day) mortality was 3.1%. Over a mean 18-month follow-up (range 2 to 39), no late graft thrombosis, stenosis, or graft migration has been seen on CT scans or X ray. Endoleak has not been detected in any aortoiliac or bifurcated graft. Aneurysm size has diminished consistently in successfully treated cases. CONCLUSIONS: The White-Yu endograft appears to offer a safe, efficacious, and minimally invasive means of excluding aneurysms from the circulation. Improvements in patient selection, surgical techniques, and equipment have reduced the incidence of endoleak and conversion to open repair over the course of the evaluation.     

Long-term results after open and semiclosed thrombendarterectomy for aortoiliac occlusive disease

OBJECTIVES: This study reviews the long-term results of 514 aortoiliac thrombendarterectomies (TEA's). DESIGN: A prospective study in a major university hospital in Switzerland. SUBJECTS: 353 male and 62 female patients with aortoiliac occlusive disease. Operative indications: disabling claudication (n=334), rest pain (n=44), and gangrene (n=37). METHODS: Open and semiclosed TEA's were performed on 167 and 347 limbs, respectively. Follow-up was continuous and complete in 97.1 % of patients over a period of more than 15 years. RESULTS: The overall life-table patency rate at 5, 10, and 15 years postoperatively were 93.4 %, 90.4 %, and 84.2 %, respectively. Fifteen years postoperatively, the patency rate of 92.3 % after open TEA was significantly higher (p<0.04) than after semiclosed TEA (79.5 %). However, similar patency rates of 69.5 % and 69.8 % were observed 20 years postoperatively. Further significant prognostic factors on patency were: anatomic localization (p<0.004), preoperative stage of arterial occlusive disease (p<0.008), and gender (p<0.007). Patient's age did not influence the outcome in terms of patency. Hospital mortality rate was 1.2 %. Early obstruction occurred in 2.2 %, leading to subsequent early amputation of 1.4 % and reoperations in 1.2 %. The long-term actuarial survival rates of the patients were 55 %, 36 %, and 18 % after 10, 15, and 20 years postoperatively. CONCLUSION: Both open and semiclosed TEA give highly satisfactory long term results in aortoiliac occlusive disease with a low morbidity and low mortality.     

Early predictors of neurodevelopmental outcome in high risk infants

The purpose of this study was to investigate mortality and morbidity rates and long-term outcome of patients who underwent emergency treatment of abdominal aortic prosthetic graft infection. Between January 1984 and December 1993, 18 men aged fifty-nine +/- sixteen years were operated on as an emergency for an acute life-threatening complication of aortic prosthetic graft infection. The grafts had been implanted for abdominal aortic aneurysm in 9 patients and aortoiliac occlusive disease in 9, from one to one hundred seventy months previously. Five (28%) patients presented with a hemorrhagic shock due to a fistula between the vascular reconstruction and the small bowel (4 patients) or the right ureter (1 patient) and 13 (72%) had generalized sepsis. The grafts were always radically explanted. Extraanatomic revascularization procedures included 6 axillopopliteal and 12 axillofemoral bypass grafts. Operative mortality was 39% (7 patients), and 3 (9%) limbs were amputated within thirty days. Two (11%) patients died after seven and twelve months, respectively, of septic complications, and 1 (5%) patient died after six months from an unrelated cause. Eight (73%) patients are still alive at a mean follow-up of fifty +/- thirty-four months, but in 3 the extraanatomic bypass was removed for infection and 5 major amputations were performed. Two-year survival and limb salvage rates were 44% and 50%, respectively. Aortic prosthetic graft infections that require emergent treatment continue to demonstrate high early and late mortality and limb loss rates despite aggressive intervention and limb salvage procedures. Newer methods of managing these complications should continue to be investigated.     

Aortic corset syndrome

The majority of proximal anastomotic complications of aortofemoral bypass grafts are related to the formation of pseudoaneurysms or true proximal aneurysmal dilation of the residual infrarenal aorta. The late development of occlusive disease at the proximal anastomosis is an extremely rare event. We report two patients in whom symptomatic stenoses developed involving the proximal anastomoses of aortofemoral bypass grafts originally placed for aortoiliac occlusive disease. Surgical exploration demonstrated the presence of a constricting prosthetic corset wrapped around the proximal suture line of each graft. Exuberant neointimal hyperplasia was responsible for both stenoses.     

Intraoperative endovascular angioplasty and stenting of iliac artery: an adjunct to femoro-popliteal bypass

BACKGROUND: With the rapid development of endovascular techniques, the management strategy of patients with multilevel atherosclerotic arterial occlusive disease is also evolving. Iliac artery stenting is a means whereby multiple bypass operations can be avoided in such patients. The early results of preoperative iliac artery stenting seem promising but the role of intraoperative iliac artery angioplasty and stenting is less clear. STUDY DESIGN: This study was undertaken to evaluate our early results of a combined endovascular and operative approach to patients with multilevel atherosclerotic arterial occlusive disease. Between June 1995 and March 1997, primary intraoperative iliac artery balloon angioplasty and stent placement were performed on 13 affected limbs of 12 patients undergoing an infrainguinal bypass operation. Indications for operation, patient demographics, and risk factors were noted. The outcome of surgery and the patency rates of bypass graft and stent were also recorded. RESULTS: The initial technical success of primary iliac artery angioplasty and stenting was 93%. An improvement of the ankle-brachial index by a mean value of 0.38 was attained after operation (p < 0.001). Clinical success, based on the criteria suggested by the Society for Vascular Surgery/International Society for Cardiovascular Surgery, was achieved in all patients. There was no operative or hospital mortality. Postoperative morbidity rate was 8% (n = 1). The cumulative 1-year patency rates of iliac stent and infra-inguinal bypass grafts were 100% and 85%, respectively. The limb loss rate was 7%. CONCLUSIONS: The technique of intraoperative angioplasty and stenting can be easily mastered by an experienced and skilled vascular surgeon, using a portable C-arm fluoroscopic unit, in the operation theater. A combined endovascular and operative approach optimizes the therapeutic option to this selected group of patients.     

Selection of surgical approaches in the treatment of aortoiliac arterial occlusive disease

31 patients with aortoiliac occlusive disease with or without infrainguinal occlusion was treated with thromboendarterectomies, aortoiliac or aortofemoral arterial bypasses, extra-anatomic bypasses and sequential arterial bypasses in the past 5 years. The results were satisfactory. The surgical mortality was 3.2%, the primary 5-year patent rate was 84.2%, and the secondary 5-year patent rate was 96.5%. We emphasize the value of ABI to indicate arterial reconstruction.     

Transluminal balloon angioplasty, stents, and atherectomy

Arterial bypass grafting for occlusive disease is still considered the gold standard in the treatment of arterial occlusive disease. However, less invasive methods are available for select patients. Percutaneous balloon angioplasty has been shown to be effective in focal iliac artery stenosis, with patency rates of 50% to 90% at 5 years. Patency rates for femoropopliteal lesions are generally less than 50% at 2 years. Complications seen with balloon angioplasty often can be treated with arterial stents. Stents can be categorized into balloon-expandable, which provide a rigid scaffold to support the artery, self-expanding, which exert radial force to resist external compression, and thermal expanding stents, which allow for the use of a smaller introducer sheath. Another treatment option is atherectomy, in which the offending lesion is removed instead of fracturing and dilating the lumen. Although overall initial results of atherectomy have not been favorable, short lesions with eccentric atheroma or intimal hyperplasia, such as those seen in dialysis access fistulas or vein graft stenoses, may respond well.     

Endoluminal grafting for aneurysmal and occlusive disease in the superficial femoral artery: early experience

PURPOSE: To examine whether endoluminal grafts (ELGs) of radically expandable polytetrafluoroethylene (PTFE) can successfully form durable internal conduits to revascularize lengthy occlusive disease and exclude aneurysms in the femoropopliteal (FP) arteries. METHODS: Under protocol, implantation of an unpredilated PTFE tube ELG anchored with Palmaz stents using a low-profile percutaneous delivery system was attempted in 50 symptomatic patients for a variety of pathologies: (1) restenosis; (2) complex lesions unlikely to be treated successfully with other endoluminal therapies; (3) acute angioplasty failure; and (4) aneurysms. There were 37 occlusions, 14 stenoses, and 2 long, combined stenotic-aneurysmal lesions in 47 native arteries, 5 FP grafts, and 1 femorotibial (FT) vein graft. Thirty-two percent of the patients had < or = vessel runoff. The average lesion length was 20.4 +/- 11.4 cm (range 1.5 to 40), and the mean preoperative ankle-brachial index (ABI) at rest was 0.53 +/- 0.14. RESULTS: In a 20-month period through April 1995, 50 patients (34 males, 16 females; mean age 69.5 years, range 45 to 87) underwent 54 procedures in 53 limbs; 55 ELGs were successfully deployed in 51 limbs; 2 patients were converted to FP bypass owing to technical problems (96% procedural success). There were 18 inhospital complications: 1 distal wire dissection repaired with an additional ELG; 2 hematomas requiring surgical repair; 1 graft collapse; 1 pseudoaneurysm at the site of a mid-ELG leak; 7 minor access sequelae; and 6 acute ELG thromboses, 4 treated with lytic therapy and balloon dilation, 1 with open thrombectomy, and 1 with bypass grafting. The mean postoperative ABI was 1.01 +/- 0.10. During the 30-day postprocedure period, 2 ELGs rethrombosed and 2 other limbs (3 ELGs) occluded; 1 thrombosis and 1 rethrombosis were lysed successfully, but the other 2 patients had an FP bypass. Over the mean 8.3 +/- 5.5 month follow-up, 6 additional ELGs occluded and 1 reoccluded; 4 were successfully treated by endovascular techniques for a primary patency of 72% and secondary patency of 84% by life-table analysis. CONCLUSIONS: Endovascular grafting is a conceptually attractive technique that has the potential to expand the current boundaries of interventional treatment. This preliminary experience attests to the feasibility and safety of ELG deployment in the superficial femoral arteries. Whether such a device can match the durability of classical revascularization techniques remains to be determined in clinical trials when device configurations and deployment techniques have been standardized.     

Combination endovascular and open treatment of peripheral arterial occlusive disease performed by surgeons

The endovascular treatment of peripheral arterial occlusive disease has historically been performed by interventional radiologists and cardiologists. With additional training in endovascular techniques, surgeons become uniquely suited to manage arterial lesions with both endovascular and conventional surgical techniques. Over a 14-month period, 13 patients underwent combination endovascular and open reconstruction on limbs with peripheral arterial occlusive disease. There were 10 males and 3 females. The mean age was 66 years. All procedures were performed in the operating room by surgery residents under the direct supervision of vascular surgeons. After intraoperative angiography, 26 arterial lesions underwent percutaneous transluminal angioplasty (aorta, 1; common iliac, 14; external iliac, 10; superficial femoral, 1). Twenty-five of 26 lesions were further treated with intraluminal stent placement, the lone exception being a case of superficial femoral artery angioplasty. Concomitant open reconstruction was performed on all limbs, 14 as outflow and 1 as inflow. There were two cases of procedural morbidity and one perioperative death secondary to myocardial infarction. There were no wound-related complications. The mean ankle-brachial index of the affected lower extremity improved from 0.41 (+/- 0.15) to 0.74 (+/- 0.14) at 30 days. Mean follow-up was 8 months (range, 2-14). Based on our early experience, simultaneous combination endovascular and open reconstruction of multisegment arterial occlusive disease can be performed safely and efficiently by surgeons.     

Clinical results of endovascular stent graft repair for fifty cases of thoracic aortic aneurysms

Between February 1995 and December 1997, 50 cases (55 lesions) of thoracic aortic aneurysms including 20 cases of aortic dissections were treated with an endovascular technique using the stent grafts. All patients were treated in the operating room under general anesthesia and the stent grafts were implanted through 18 Fr. or 20 Fr. sheaths via femoral arteries under fluoroscopic guidance. The stent graft was composed of several units of self-expanding stainless-steel Z stents covered with an ultra-thin polyester fabric. Stent graft deployment was technically successful in 53 of 55 lesions (delivery success rate: 96.4%). Exclusion of the aneurysms and entry closing without endoleak were achieved within two weeks after the operation in 43 of 53 lesions (initial success rate: 81.1%). Endoleak was found in 10 lesions (minor endoleak: 8 and major endoleak: 2 lesions). Two patients died in the periopertive period of delivery failures as injury to external iliac artery and damage to the delivery sheath caused by tortuous and narrow access routes. Endovascular stent graft repair of thoracic aortic aneurysms is minimally invasive operation in comparison with conventional surgical graft replacement with extracorporeal circulation. These early results suggest that the stent graft repair is possibly safe and useful treatment for the patients of thoracic aortic aneurysms especially in high risk patients. However, careful long-term follow-up is necessary to prove the value and the effects of this endovascular treatment and improvement of the stent graft system and technical training of endovascular surgery for operators are required to reduce the delivery failure and to determine the stent graft repair is reliable treatment.     

Results and complications after endovascular reconstruction of aortic aneurysms

Between August 1994 and December 1996 137 patients (10 female and 127 male, mean age 66 yrs., range 27-85) with aortoiliac aneurysmal disease were treated with endovascular stent grafts. Pathology included 5 thoracic, 131 abdominal and 1 isolated iliac artery aneurysm. 88 straight tube grafts (75 Mintec, 12 EVT, 1 Chuter) and 43 bifurcated grafts (21 Mintec, 20 EVT, 2 Chuter) were implanted in the infrarenal aorta. 5 (Mintec) tube grafts were used for the thoracic aneurysms. One tapered tube graft was used to exclude the isolated iliac aneurysm. 11 patients (8%) required conversion to open surgical repair. This was due to defective devices in 5, device related occlusion of a renal artery in 2, aortic dissection in 1, occlusion of iliac outflow in 1, a large unmanageable proximal endoleak in 1 and a retroperitoneal bleeding resulting in hemorrhagic shock in 1 patient. There was one procedure related death for a mortality of 0.7%. Patients were followed every 3-6 months using CT with i.v. contrast and ultrasound duplex examinations with adjunctive usage of an intravenous ultrasound contrast agent (Levovist, Schering AG). Intraarterial DSA was used only when called for by thrombotic or stenotic complications. At a mean follow-up of 9.2 months (range 2-24 months) 16 (17%) primary and 8 (8.5%) secondary leaks (at the distal anchoring zone) were detected after implantation of tube grafts. 11 (25.6%) leaks were detected after implantation of bifurcated grafts. Iliac artery occlusion was observed in 2 patients after placement of a straight endograft, 6 times after reconstruction with a Mintec bifurcated device and 3 times after implantation of an EVT bifurcated endograft. Successful treatment of iliac artery occlusion without the need for subsequent amputation or major disability included extraanatomic bypass in 7 patients, PTA (3 patients) and implantation of wallstents (2 patients) or conservative management (1 patient).     

Current status of the use of retroperitoneal approach for reconstructions of the aorta and its branches

OBJECTIVE: The objective of this article is to determine whether retroperitoneal approach for aortic surgery has certain physiologic, technical advantages. SUMMARY BACKGROUND DATA: The retroperitoneal approach for abdominal aortic reconstruction classically had been reserved for select patients with either high-risk comorbid disease or specific anatomic problems that preclude the transabdominal approach. With increasing appreciation of the physiologic, anatomic, and technical advantages of the extended posterolateral retroperitoneal approach, the authors have expanded its use for repair of all types of aortic visceral and renal artery disease as well as ruptured abdominal aortic aneurysm and infected aortic grafts. METHODS: From January 1981 to September 1995, 2340 retroperitoneal aortoiliac reconstructions were performed in 2243 patients. Aortic reconstructions accounted for 1756 cases: 1109 for elective abdominal aortic aneurysms, 210 for ruptured and symptomatic aortic aneurysms, 399 for occlusive disease, 18 for infected aortic grafts, and 20 for other indications. Iliofemoral disease was the indication for 584 procedures. As experience was gained, this approach also was used for 417 renal and 50 celiac and superior mesenteric artery reconstructions. RESULTS: The mean age was 67 years with 1590 men and 653 women. Overall mortality was 5.2% for all aortic cases: 2.4% for elective, 12.6% for symptomatic, and 29.0% for ruptured aortic aneurysms. Major complications occurred in 12.5% of the elective procedures and in 38.3% of emergency procedures. Over the past 5 years, the average length of hospital for uncomplicated elective abdominal aortic aneurysms was 6.1 days, intensive care unit stay was 0.7 day, and diet was resumed by postoperative day 1. Five-year graft patency was 99% for aneurysms and 95% for occlusive disease. CONCLUSIONS: The retroperitoneal approach offers certain physiologic advantages associated with minimal disturbance of gastrointestinal and respiratory function, thereby reducing the length of intensive care unit and hospital stay. In addition, its technical advantages and flexibility facilitates visceral and juxtarenal aortic reconstructions without the need for thoracotomy.     

Ultrasmall superparamagnetic iron oxide particles (AMI 227) as a blood pool contrast agent for MR angiography: experimental study in rabbits

We report a case of successful surgical management of a potentially life-threatening complication of aortoiliac stent placement. A 59-year-old man who had Leriche syndrome underwent bilateral iliac artery and infrarenal aortic stent placement at another institution. His history was significant for retroperitoneal lymph node dissection at 19 years of age for testicular cancer. One week after stent placement, the patient was readmitted with abdominal pain, poor oral intake, and diffuse intermittent tenderness. Evaluation with computed tomographic scanning and endoscopy was unremarkable, and the patient was discharged. He was admitted to our institution 1 week later with persistent abdominal pain. A computed tomographic scan of the abdomen revealed a large pseudoaneurysm of the abdominal aorta. The patient underwent urgent exploration, and exclusion of his infrarenal aorta was achieved with aortobifemoral bypass grafting. After the operation, the patient's course was complicated by a large paraduodenal hematoma, which resulted in a gastric outlet obstruction, which was managed without operation. This case illustrates a potential life-threatening complication of extensive stent placement for aortoiliac occlusive disease. Injury to the abdominal aorta must be considered in a symptomatic patient after the placement of stents in the aortoiliac region, beyond the immediate periprocedural period.