Differential effect of unfractionated heparin and low molecular weight heparin on intravascular tissue factor pathway inhibitor: evidence for a difference in antithrombotic action

PURPOSE: Successful endovascular repair of an abdominal aortic aneurysm (AAA) requires the creation of a hemostatic seal between the endograft and the underlying aortic wall. A short infrarenal aortic neck may be responsible for incomplete aneurysm exclusion and procedural failure. Sixteen patients who had an endograft positioned completely below the lowest renal artery and 37 patients in whom a porous portion of an endograft attachment system was deliberately placed across the renal arteries were studied to identify if endograft positioning could impact on the occurrence of incomplete aneurysm exclusion. METHODS: Fifty-three patients underwent aortic grafting constructed from a Palmaz balloon expandable stent and an expandable polytetrafluoroethylene (ePTFE) graft implanted in an aorto-ilio-femoral, femoral-femoral configuration. Arteriography, duplex ultrasonography and spiral CT scans were performed in each patient before and after endografting to evaluate for technical success, the presence of endoleaks, and renal artery perfusion. RESULTS: There was no statistically significant difference in patient demography, AAA size, or aortic neck length or diameter between patients who had their endografts placed below or across the renal arteries. However, significantly more proximal aortic endoleaks occurred in those patients with infrarenal endografts (P < or = .05). Median serum creatinine level before and after endografting was not significantly different between the 2 patient subgroups, with the exception of 2 patients who had inadvertent coverage of a single renal orifice by the endograft. Median blood pressure and the requirement for antihypertensive therapy remained the same after transrenal aortic stent grafting. Significant renal artery compromise did not occur after appropriately positioned transrenal stents as shown by means of angiography, CT scanning, and duplex ultrasound scan. Mean follow-up time was 10.3 months (range, 3 to 18 months). Patients who had significant renal artery stenosis (> or =50%) before aortic endografting did not show progression of renal artery stenosis after trans-renal endografting. Two patients with transrenal aortic stent grafts had inadvertent coverage of 1 renal artery by the endograft because of device malpositioning, which resulted in nondialysis dependent renal insufficiency. In addition, evidence of segmental renal artery infarction (<20% of the kidney), which did not result in an apparent change in renal function, was shown by means of follow-up CT scans in 2 patients with transrenal endografts. CONCLUSION: Transrenal aortic endograft fixation using a balloon expandable device in patients with AAAs can result in a significant reduction in the risk of proximal endoleaks. Absolute attention to precise device positioning, coupled with the use of detailed imaging techniques, should reduce the risk of inadvertent renal artery occlusion from malpositioning. Long-term follow-up is essential to determine if there will be late sequelae of transrenal fixation of endografts, which could adversely effect renal perfusion.     

Natural history of the residual infrarenal aorta after infrarenal abdominal aortic aneurysm repair

PURPOSE: We determined the natural history of the residual native infrarenal aortic segment after conventional abdominal aortic aneurysm (AAA) repair. METHODS: For the retrospective arteriographic case series, 800 hundred translumbar aortograms (TLAs) were obtained for 272 patients, before and after conventional AAA repair. The main outcome measures were changes in the aortographic diameter and the length of the infrarenal aortic segment, corrected and uncorrected for magnification by normalization to the first lumbar vertebral body height. RESULTS: The mean follow-up time from the preoperative TLA to the most recent postoperative TLA was 42 months (range, 1 to 257 months). Vertebral body height did not change (p = 0.35). The length of the native infrarenal aorta cephalad to the proximal anastomosis increased a mean of 3 mm, from 23 to 26 mm (p = 0.001). However, in 115 patients (43%), this aortic segment elongated more than 5 mm, and in 63 patients (24%), it elongated more than 10 mm. The native residual infrarenal aorta above the proximal anastomosis dilated a mean of 1 mm, from 23 to 24 mm (p = 0.001), but in 21 patients (8%), it dilated more than 5 mm. There was a weak positive correlation between the increase in residual native aortic diameter and duration of follow-up. There was a negative correlation between this increase and the initial size. The diameters of the proximal anastomosis and proximal graft did not change. Marked variability in the changes in aortic dimensions was observed. CONCLUSIONS: A mean period of 42 months after conventional AAA repair, the native infrarenal aortic segment elongates and dilates. Although such enlargement is statistically significant, the average increase appears to be small. However, residual aortic cuff diameter increased more than 5 mm and neck length more than 10 mm in a significant number of patients, with potentially serious implications for endovascular treatment of AAA.     

Congenital malformations in infants of 517 pregestational diabetic mothers

PURPOSE: To explore a method of combined endovascular/conventional treatment of abdominal aortic aneurysm (AAA), in which the iliac arteries are reconstructed by conventional surgical techniques to provide the anatomic substrate for subsequent endovascular repair of the aortic aneurysm. METHOD: A 77-year-old patient with severe cardiac disease was found to have a 6.5-cm AAA, bilateral common iliac artery (CIA) aneurysms, and diffusely narrowed, tortuous external iliac arteries. The left internal iliac artery was occluded. At operation, the right CIA was exposed through a transverse retroperitoneal incision under epidural anesthesia. An iliobifemoral bypass was constructed using a preformed bifurcated graft. A stent-graft was delivered through the right limb of the bifurcated iliobifemoral graft. The proximal end of the stent-graft was implanted in the neck of the aneurysm, and the distal end was deployed in the common trunk of the iliobifemoral graft, thereby excluding the AAA and both native iliac arteries from prograde arterial flow. RESULTS: Completion angiography and follow-up contrast computed tomography showed the aneurysm to be excluded from the circulation. The patient was not intubated, was never hemodynamically unstable, and had aortic blood flow interrupted for no more than 20 seconds. In addition, he was able to resume his usual diet on the first postoperative day. He continues to be well and without evidence of endoleak at 6-month follow-up. CONCLUSIONS: This case demonstrates that iliac artery stenosis, tortuosity, and aneurysmal dilatation are not impediments to endovascular AAA exclusion. Any necessary surgical modifications of pelvic arterial anatomy can be performed before stent-graft insertion to minimize aortic occlusion time.     

Andersen''s syndrome: a distinct periodic paralysis

PURPOSE: To develop a stable, transluminally created abdominal aortic aneurysm (AAA) within a live animal model. MATERIALS AND METHODS: Eight mongrel dogs were utilized to evaluate a new, catheter-based technique for the creation of an AAA. With use of a standard angioplasty balloon and a balloon-expandable intravascular metallic stent, the infrarenal abdominal aorta was overdilated to twice its measured diameter into a fusiform shape AAA in eight dogs. At 30 days, aortography was performed, the dogs were killed, and the aorta was resected and evaluated for histopathology. RESULTS: Seven of the eight dogs that underwent transluminal AAA creation survived the initial procedure. A stable, fusiform AAA was successfully created in these seven dogs. At 30 days, repeat angiography and histologic examination confirmed that the seven AAAs were still twice the diameter of the normal aorta (a four-fold increase in luminal area), that the branch arteries remained patent, and that the lumen was endothelialized. One of the eight dogs was killed 9 hours after the procedure because of inability to awaken from anesthesia. Gross and histopathologic results in this one dog also demonstrated an intact aorta containing an AAA. CONCLUSIONS: A stable, infrarenal AAA model can be successfully created in the canine species with use of standard catheter-based techniques and equipment. This model can be used to test emerging endovascular treatments of AAA.     

Chronic rupture of abdominal aortic aneurysms

INTRODUCTION: Rupture of abdominal aortic aneurysms (RAAA) can take place in one of the 4 following ways: 1. "Open" rupture in the free peritoneal cavity; 2. "Closed" rupture with formation of retroperitoneal haematoma; 3. Rupture into surrounding cavity structures, such as veins and bowels; 4. In rare cases rupture is effectively "sealed of" by the surrounding tissue reaction, and retroperitoneal haematoma is "chronically" contained [1]. The terms "sealed" [2], "spontaneously healed" [3], "leakig" [4] RAAA, were also used in the previous papers connected to this situation. The "sealed" rupture was first described by Szilagyi and associates in 1961 [2]. In their case the rupture was small and haemorrhage was effectively encircled by the tissue surrounding the aortic wall. The slow rate of blood loss contributed to the patient's haemodinamically stable condition. Christenson et al. reported a case of "spontaneously healed" RAAA [3]. Rosenthal and associates described 2 patients who had aortic aneuryms that ruptured several months before repair and contributed to the term "leaking AAA" [4], while Jones et al. introduced the term "chronic contained rupture" [1]. The aim of this paper is the presentation of 5 such patients. CASE REPORT: Between December 1, 1988 and May 30, 1997 411 patients with abdominal aortic aneurysms (AAA) have been operated at our institute. Of this number 137 (33%) had RAAA, while 5 patients (12%) had a contained RAAA (CRAAA). CRAAA were found in 3 male and two female patients, average age 62 years. All of them had a previously proved AAA and initial symptoms lasted for days or months before the admission. In all patients haematocrit, pulse rate and arterial tension during the admission, were normal. All typical signs of RAAA were absent in these patients. Patient 1. A 56-year-old man, smoker, with previous history of arterial hypertension had an isolated episode of abdominal pain and collapse 30 days before the admission. Physical examination revealed a pulsatile abdominal mass. Doppler ultrasonography identified an infrarenal AAA, with right lobular extraaneurysmal mass which displaced the inferior vena cava (ICV). Angiographically (Figure 1a) an unusual saccular intrarenal AAA was detected, while simultaneous cavography (Figure 1b) confirmed the-dislocated inferior vena cava to the right. The intraoperative finding showed infrarenal CRAAA with organized retroperitoneal haematoma between AAA, ICV and duodenum. After aortic cross clamping and aneurysmal opening, the rupture at the right posterior aneurysmal wall was discovered. The partial aneurysmactomy and aortobilliar bypass procedure with bifurcated knitted Dacron graft (16 x 8 mm), were performed. The patient recovered very well. After a 4-year follow-up period the graft is still patent. Patient 2. A 72-year-old woman with low back pain, fever and disuric problems was urgently admitted to the Institute of Urology and Nephrology. The standard urological examination (X-ray, intravenous pyelography, retrograde urography, kidney Duplex ultrasonography) excluded urological diseases. However, intrarenal AAA an a giant aneurysm of the right common iliac artery, were found. The proximal dilatation of the right excretory urinary system was also found by retrograde urography. The patient was transported to our Institute 20 days after the initial symptoms. Translumbar aortography (Figure 3) showed the right common iliac artery aneurysm and gave the false negative picture of normal abdominal aorta because of parietal thrombosis of AAA. The intraoperative finding showed chronic rupture of the posterior wall of the right common artery aneurysm. The retroperitoneal haematoma compressed the right ureter. Both aneurysm have been resected and replaced by bifurcated Dacron graft (16 x 8 mm). The patient recovered successfully. After a 2-year period of follow-up the graft is still patent. Patient 3. (ABSTRACT TRUNCATED)     

Experience of reoperations followed by repairs of abdominal aortic aneurysms

We experienced 8 cases who required reoperations, including 2 re-redo operations, after repairs of infrarenal abdominal aortic aneurysms. Of 8 patients, one patient developed a new aneurysm due to atherosclerosis in thoraco-abdominal aorta involving all visceral arteries and other 7 patients had aneurysmal formations at proximal anastomotic sites, including 3 suprarenal, 2 juxtarenal and 2 infrarenal aortic lesions. Etiology at initial operation in patients who subsequently developed anastomotic aneurysms included vasculo-Beh?et disease in 4, atherosclerosis in 2 and dissecting aortic aneurysms type III due to Marfan syndrome in 1. At reoperation, all who had vasculo-Beh?et disease had ruptures of anastomotic sites and 2 patients underwent repairs of dehiscent patch, 1 extra-anatomic bypass between ascending and abdominal aorta and 1 interposition of graft. One patient who had graft infection after repair of abdominal aortic aneurysm required axillo-femoral bypass with removal of infected graft. A patient who had dehiscence of proximal anastomosis after repair of aortoiliac occlusive disease required interposition of graft. Two patients, Marfan syndrome and aneurysm in thoraco-abdominal aorta, underwent graft replacement of thoraco-abdominal aorta concomitant with reconstruction of all visceral arteries. There were 8 patients who required reoperations for aneurysms at distal anastomotic sites after repairs of abdominal aortic aneurysms. Five patients underwent repairs of new aneurysms, including replacement of total arch in 3, descending aorta in 1 and iliac artery in 1. In all cases, no hospital death was noted, however, late deaths were occurred in vasculo-Beh?et disease, Marfan syndrome and graft infection. Thus, late result depends on etiology of disease. Although patients who requires reoperation after repair of abdominal aortic aneurysms have higher operative risk factors, early and late results are satisfactory compared to initial operations.     

Successful embolization of persistent endoleak from a patent inferior mesenteric artery

PURPOSE: To report the successful endovascular occlusion of a persistent endoleak owing to collateral perfusion in a 1-year-old bifurcated aortic endograft. METHODS AND RESULTS: An 81-year-old man underwent endovascular repair of a 5.5-cm abdominal aortic aneurysm (AAA) with a bifurcated stent-graft in 1995; collateral perfusion of the excluded aneurysm by retrograde filling of the patent inferior mesenteric artery (IMA) was noted postoperatively. At his 1-year follow-up, the mid-sac endoleak persisted on contrast-enhanced computed tomography. Using the superior mesenteric artery for access, the stump of the IMA was successfully embolized with glue. CONCLUSIONS: This case, which highlights the importance of documenting a patent IMA prior to AAA endografting, illustrates one option for the management of persistent collateral perfusion of endovascularly excluded aneurysms.     

Screening for chromosomal abnormality

PURPOSE: To investigate if stents with hooks and barbs will improve stent-graft fixation in the abdominal aorta. METHODS: Sixteen- to 24-mm-diameter Dacron grafts were deployed inside cadaveric aortas. The grafts were anchored by stents as in endovascular abdominal aortic aneurysm repair. One hundred thirty-seven stent-graft deployments were carried out with modified self-expanding Z-stents with (A) no hooks and barbs (n = 75), (B) 4 5-mm-long hooks and barbs (n = 39), (C) 8 10-mm-long, strengthened hooks and barbs (n = 19), or (D) hooks only (n = 4). Increasing longitudinal traction was applied to determine the displacement force needed to extract the stent-grafts. The radial force of the stents was measured and correlated to the displacement force. RESULTS: The median (interquartile range) displacement force needed to extract grafts anchored by stent A was 2.5 N (2.0 to 3.4), stent B 7.8 N (7.4 to 10.8), and stent C 22.5 N (17.1 to 27.9), p < 0.001. Both hooks and barbs added anchoring strength. During traction, the weaker barbs were distorted or caused intimal tears. The stronger barbs engaged the entire aortic wall. The radial force of the stents had no impact on fixation, while aortic calcification and graft oversizing had marginal effects. CONCLUSIONS: Stent barbs and hooks increased the fixation of stent-grafts tenfold, while the radial force of stents had no impact. These data may prove important in future endograft development to prevent stent-graft migration after aneurysm exclusion.     

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.     

Role of magnetic resonance angiography for assessment of abdominal aortic aneurysm before endoluminal repair

BACKGROUND: A detailed knowledge of the morphology of the aorta and iliac arteries is an important prerequisite for successful endoluminal abdominal aortic aneurysm (AAA) repair. The best method of preoperative evaluation remains to be determined. METHODS: A prospective study was undertaken between January 1994 and July 1995 to assess the ability of computed tomography (CT), magnetic resonance angiography (MRA), colour duplex imaging and intra-arterial digital subtraction angiography (IA-DSA) to visualize AAA morphology. RESULTS: Eighty-two consecutive patients (64 men, 18 women) with AAA were assessed with MRA, contrast-enhanced CT, colour duplex imaging and IA-DSA. Median age was 74 (range 59-87) years and median AAA diameter was 5.7 (range 3.5-9.7) cm. Five patients were unable to tolerate CT or MRA examination. Seventy-seven patients underwent both CT and MRA. Of these, 55 also had a colour duplex scan and 32 underwent arteriography. The scans were assessed by an independent blinded observer. MRA was significantly better (P < 0.01) at visualizing AAA morphology compared with CT and colour duplex imaging. There was no statistically significant difference between MRA and arteriography. CONCLUSION: MRA is useful in patient selection for endoluminal AAA repair, as it avoids use of iodinated contrast medium and ionizing radiation.     

Comparative efficacy of chloroquine plus chlorpheniramine and halofantrine in acute uncomplicated falciparum malaria in Nigerian children

A 47-year-old woman on long-term hemodialysis due to a chronic isolated abdominal aortic dissection was admitted to our department with severe abdominal pain. She had not suffered any hematemesis or melena. An emergency laparotomy revealed an abdominal aortic aneurysm with a diameter of 60mm, densely adhered to the ileum. An aortoenteric fistula manifesting as intramural rupture into the ileum was found after infrarenal abdominal aortic and bilateral common iliac cross-clamping. The fistula on the ileac side was nontransmural, but that on the aortic side communicated with the pseudolumen of the abdominal aorta, and contained mural thrombus. The infrarenal abdominal aorta and bilateral common iliac arteries were replaced with a collagen-sealed woven Dacron bifurcated graft. Histological examination of the ileum in this portion showed intramural bleeding and xanthomatous granulation with foam cell infiltration in the thickened subserosa. While it is difficult to diagnose nonpenetrating aortoenteric fistula preoperatively, such a fistula must be considered in a patient with severe abdominal pain, for whom previous abdominal aortic surgery has been performed or when an abdominal aneurysm is observed. To our knowledge, no other case of an aortoenteric fistula presenting as an intramural rupture into the ileum in an isolated abdominal aortic dissection has ever been reported.     

Undiagnosed scleroderma in a patient with a difficult airway

BACKGROUND: We report one case of symptomatic aneurysm of infrarenal abdominal aorta in a patient symptomatic for acute abdomen. METHODS: The patient was accepted at the Emergency Care Unit and the routine admission tests were taken. US of the abdomen revealed a (SVI) disposition of the organs and an aneurysm of the abdominal aorta below the renal arteries. Patient underwent an aorto-aortic straight graft CONCLUSIONS: In this case-report we show SVI cannot be considered a problem in the surgical treatment of symptomatic abdominal aortic aneurysms.     

Infrarenal aortic dimensions in siblings of patients with infrarenal abdominal aortic aneurysm or aortoiliac occlusive disease

OBJECTIVE: To compare the dimensions of the infrarenal aorta and the prevalence of undiagnosed infrarenal abdominal aortic aneurysms in the siblings of patients operated on for either infrarenal abdominal aortic aneurysm or aortoiliac occlusive disease. DESIGN: Prospective screening study. SETTING: University hospital, Finland. SUBJECTS: 220 siblings of patients operated for either abdominal aortic aneurysm or aortoiliac occlusive disease. INTERVENTIONS: Abdominal aortic ultrasound. MAIN OUTCOME MEASURES: Anteroposterior and transversal diameters of infrarenal and suprarenal aorta. RESULTS: There was a group of 5 siblings (4 men and 1 woman, aged 59 years or more) among the aneurysm patients who had a disposition to infrarenal aneurysm formation defined as a dilatation of 30 mm or more. This contrasted with none among the siblings of the patients with aortoiliac occlusive disease (p = 0.07, 95% confidence interval 0.49 to 165.3). The two factors affecting the diameter of the infrarenal aorta were age and sex. The aortic dimensions tended to be bigger in the siblings of the aneurysm patients but the differences were not significant. The ratio of infrarenal to suprarenal diameter was bigger in the siblings of the aneurysm patients also after excluding the cases with detected dilatations (p = 0.05) and in the multivariate analysis the only factor explaining this difference was the type of the disease of the proband. CONCLUSIONS: The screening of male siblings (over 55 years old) of patients with infrarenal abdominal aortic aneurysms might be justified.     

Endovascular management of "endoleaks" after transluminal infrarenal abdominal aneurysm repair

PURPOSE: To investigate the reasons for endoleaks after transluminal infrarenal abdominal aneurysm management and the potential for transluminal interventions in subsequent management. METHODS: Prospective analysis of 50 consecutive patients undergoing endovascular aneurysm repair at a single institution with Stentor and Vanguard grafts from March 1995 to March 1997. SETTING: Academic teaching hospital. RESULTS: Two procedures were converted for other reasons than leak. In the remaining 48 successful procedures endoleaks were detected in 11 (22.9%): proximal aortic leak (2.1%), distal aortic leak (8.3%), iliac leak (12.5%). Leaks were treated at the initial procedure in five patients, resulting in 87.5% excluded aneurysms. Twelve and a half per cent were discharged with a primary leak. Redo was performed on all iliac leaks within 7 weeks. All aortic leaks showed spontaneous thrombosis within 3 months, but reappeared with local aneurysm expansion. Aortic redo-procedures were performed by proximal tubular extension or converting a tube graft into a bifurcation graft. All rescue procedures were successful. Secondary leaks have been observed twice in this series, both treated by endovascular means. CONCLUSIONS: Endovascular treatment of primary and secondary endoleaks is possible, and may be a safe alternative to a difficult open procedure.     

Fate of the excluded abdominal aortic aneurysm sac: long-term follow-up of 831 patients

PURPOSE: Nonresective treatment of the infrarenal abdominal aortic aneurysm by proximal and distal ligation of the aneurysm sac (exclusion) combined with aortic bypass has been previously reported. A 10-year experience with 831 patients undergoing this procedure was reviewed. METHODS: From 1984 to 1994, 831 (761 elective, 70 urgent) of 1103 patients being treated for abdominal aortic aneurysm underwent repair with the retroperitoneal exclusion technique. Perioperative morbidity and mortality, estimated blood loss, transfusion requirements, natural history of the excluded aneurysm sac, and long-term survival were all assessed. RESULTS: The operative mortality rate for patients undergoing exclusion and bypass was 3.4%. The incidence of nonfatal perioperative complications was 5.2%. Colon ischemia requiring resection occurred in 2 (0.2%) of the 831 patients. Estimated blood loss was 638 +/- 557 cc (50 to 330 cc). On follow-up 17 (2%) patients were found to have patent aneurysm sacs as detected by duplex examination. Fourteen patients required surgical intervention. No cases of graft infection or aortoenteric fistula have been noted. CONCLUSION: Retroperitoneal exclusion and bypass is a viable alternative to traditional open endoaneurysmorraphy in surgery for abdominal aortic aneurysm. Most excluded aneurysm sacs have thrombosis without any long- or short-term complications; however, in a small number of patients delayed rupture of patent aneurysm occurs, thus emphasizing the need for diligent follow-up and appropriate intervention.     

Endovascular treatment of abdominal aortic aneurysms. Morphology of aneurysms as one of the deciding indicating factors

Endovascular treatment of aneurysms of the abdominal aorta is based on intravascular bridging of the aneurysm using of an endovascular prosthesis. The prosthesis must be safely anchored above and below the sac of the aneurysm in the non-dilated artery. Therefore the indication of endovascular treatment depends on the morphology of the aneurysm. The objective of the work was to analyse the morphology of the aneurysm with regard to the possibility of endovascular treatment. The morphology of the aneurysm was evaluated with regard to the angiographic examination and examination by computed tomography. The following parameters were investigated: diameter and length of the proximal and distal neck, diameter of the sac in two planes, diameter and tortousity of the iliac arteries, tortousity of the infrarenal aorta. A total of 70 patients with aneurysms of the abdominal aorta were examined. The patients were divided into three groups according to the morphology of the aneurysm. I. infrarenal aneurysms not affecting common iliac artery (n = 20) 28.5%, II. infrarenal aneurysms affecting common iliac artery (n = 38) 54.2%, III. juxtarenal aneurysms regardless of the affection of common iliac arteries (n = 12) 17.1%. Of the total of 70 examined patients 24 (34.2%) with infrarenal aneurysm and 6 (8.57%) with juxtarenal aneurysm were suitable for endovascular treatment.     

Abdominal aortic aneurysms in sheep: prevention of rupture with endoluminal stent-grafts

PURPOSE: The authors evaluated the ability of an aortic balloon-expandable endovascular stent-graft to prevent rupture in a model of spontaneously rupturing abdominal aortic aneurysms in sheep. MATERIALS AND METHODS: Aneurysms were created in 16 sheep by inserting a 60 x 18-mm segment of the left internal jugular vein, end-to-end anastomosed, to the sectioned infrarenal abdominal aorta. The sheep were randomly assigned into two groups; eight animals underwent endovascular implantation of an 80 x 12-mm balloon expandable stent-graft (group A), and eight were only followed up (group B). RESULTS: In group B, seven of eight animals had died of aneurysmal rupture by 3 months. In group A, six of the eight aortic aneurysms were immediately excluded, and six animals were alive at 3 months without rupture. The 3-month survival rate was 100% in group A and 12% in group B (P = .0023). Macro- and microscopic analysis of the section of the aorta in which the stent-graft had been placed revealed rapid retraction of the aneurysmal sac. CONCLUSION: Placement of an endovascular stent-graft induced regression of a branchless aneurysm and prevented rupture.     

Anterior patch aortic aneurysm model for the study of endoluminal grafts

Endovascular graft repair for aortic aneurysms has led to concerns regarding the healing characteristics of the graft within a thrombus-lined aneurysm and the effect that collateral flow may have on the endoluminal prosthesis and the aneurysm. An anterior aortic patch aneurysm model that preserved collateral arteries was examined and modified to address these issues. In canines (n = 30) a Dacron knitted patch (n = 27) or a rectus fascia patch (n = 3) was sutured into a 3.5-cm anterior aorotomy. Dacron patch aneurysm diameter was an average of 21.8 +/- 2.2 mm (mean canine normal aortic diameter 9.06 +/- 0.79 mm). Canines underwent angiogram, computed tomography, and/or intravascular ultrasound from 1 to 11 weeks later, at which time an endoluminal prosthesis was deployed and followed 30 to 60 days until harvest. Aneurysms accumulated minimal thrombus through the initial 11 weeks. Significant stenosis (mean 21.2% +/- 19%) occurred at aneurysm necks in association with a patch imbrication suture technique (n = 11). Following modification (n = 16), this decreased to a mean of 3.6 +/- 9.7%. Collateral lumbar artery patency was 95% at the time of imaging prior to graft placement. Following successful graft implantation, 16 of 18 aneurysms were filled with thrombus and in most cases the collateral circulation occluded. One of three fascial patch aneurysms ruptured 21 days after creation. This model more accurately depicts abdominal aortic aneurysms with the inherent thrombus and collateral flow that is important when studying aspects of endovascular aortic graft repair.     

The fate of the infrarenal aortic neck after open aneurysm surgery

PURPOSE: The long-term success of the endovascular repair of abdominal aortic aneurysms is dependent on the secure fixation of the stent graft at the proximal and distal attachment sites. A progressive dilatation of the infrarenal neck may jeopardize this success. The data regarding this issue are scarce. However, the long-term fate of the infrarenal neck can be studied in patients who have undergone open aneurysm surgery. This was the purpose of the present investigation. METHODS: Between January 1989 and December 1993, 64 patients underwent open repair of infrarenal abdominal aortic aneurysms. Of the 36 patients who were eligible for the study, 19 had preoperative computed tomography scans that were available. The 19 patients also underwent a new computed tomography scanning at a mean of 71 +/- 12 months after surgery. RESULTS: The mean preoperative aortic diameter was 25.4 +/- 3.7 mm at the infrarenal neck, 24.8 +/- 3.4 mm at the level of the renal arteries, and 26.7 +/- 3.0 mm at the level of the superior mesenteric artery (SMA). The mean aortic diameter increased at all of the 3 levels: +2.8 +/- 3.1 mm (P =.0014) at the infrarenal neck, +2.8 +/- 3.0 mm (P =.0013) at the level of the renal arteries, and +1.3 +/- 3.0 mm (P = .080) at the level of the SMA. The annual growth rate was 0.48 mm/y (P = .0023) at the infrarenal neck, 0.46 mm/y (P =.0010) at the level of the renal arteries, and 0.21 mm/y (P = .5811) at the level of the SMA. No correlation was found between the preoperative infrarenal neck diameter (r = .295, P = .2194), the preoperative aortic diameter at the level of the renal arteries (r = .302, P = .2088), and the preoperative aortic diameter at the level of the SMA (r = .314, P =. 2043) and the corresponding growth rates. The patients were stratified into 2 groups one with a small annual growth rate at the infrarenal neck (n = 11; 0.3 mm/y) and no differences in the preoperative infrarenal neck diameter or the clinical characteristics were found between the groups. CONCLUSION: This investigation shows an aortic dilatation of the infrarenal neck and of the aorta at the level of the renal arteries of approximately 0.5 mm annually after open aneurysm surgery. This dilatation raises concern regarding the long-term success after endovascular repair. The data also indicate that 2 populations might exist with regard to the annual growth rate of the infrarenal neck one with low growth rate and one with higher growth rate. This might be of interest for the future selection of patients for endovascular repair.     

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.