Stent-graft Exclusion Research Articles

Endovascular treatment of postlaminectomy aortic pseudoaneurysm

Aortic pseudoaneurysm following lumbar laminectomy is a rare but potentially life-threatening complication. We report a case of a 49-year-old female patient who developed a pulsatile abdominal mass and pain following a lumbar laminectomy procedure. An aortic pseudoaneurysm was diagnosed which was successfully treated with endovascular stent-graft exclusion. This report represents the first case of endovascular exclusion of a laminectomy-related aortic pseudoaneurysm. Physicians should be aware of this complication in patients who developed abdominal pulsatile mass with pain following lumbar laminectomy procedure.

Total Robotic Ligation of Inferior Mesenteric Artery for Type II Endoleak after Endovascular Aneurysm Repair

We present a case of totally robotic ligation of the inferior mesenteric artery (IMA) for treatment of a persistent endoleak from the IMA into the aneurysm sac after endovascular aneurysm repair (EVAR). An 84-year-old male underwent EVAR with a Gore Excluder stent graft for an asymptomatic infrarenal abdominal aortic aneurysm. Follow-up computed tomographic (CT) scan showed persistent type II endoleak from the IMA, with progressive enlargement of the aneurysm sac from 5 to 6.1 cm over an 18-month period. In this case, the patient underwent ligation of the IMA using the da Vinci Surgical System for the treatment of retrograde flow into the aneurysm sac. The total operating time was 249 min; of this, the robotic assistance time was approximately 180 min. No intraoperative complications occurred. The estimated blood loss was 50 mL and the urine output 650 mL. The patient was extubated immediately after the procedure and tolerated a regular diet the following day. He was discharged home with a urinary catheter on postoperative day 2. CT scan postoperatively and at 3-month follow-up demonstrated an occluded IMA and stabilization of the aneurysm sac size.

Endovascular Repair of an Actively Hemorrhaging Stab Wound Injury to the Abdominal Aorta

Traumatic injury of the abdominal aorta is rare and potentially lethal (Yeh et al., J Vasc Surg 42(5):1007-1009, 2005; Chicos et al., Chirurgia (Bucur) 102(2):237-240, 2007) as it can result in major retroperitoneal hemorrhage, requiring an urgent open surgery. In case of concomitant bowel injury or other conditions of hostile abdomen, endovascular repair can be an alternative treatment. This case report deals with a 50-year-old man presenting at the emergency ward with three stab wounds: two in the abdomen and one in the chest. During explorative laparotomy, liver laceration and bowel perforation were repaired. One day later, abdominal CT-scan revealed an additional retroperitoneal hematoma associated with an aortic pseudoaneurysm, located anteriorly 3 cm above the aortic bifurcation. Because of the risk of graft infection, an endovascular repair of the aortic injury using a Gore excluder stent-graft was performed. Radiological and clinical follow-up revealed a gradual shrinkage of the pseudo-aneurysm and no sign of graft infection at two years' follow-up.

Effect of the size of abdominal aortic aneurysm on endovascular exclusion and its results

To evaluate the effect of the diameter of abdominal aortic aneurysm (AAA) on endovascular exclusion (EVE) and its results. From March 1997 to June 2007, 429 AAA patients were treated with endovascular stent-graft exclusion. According to the maximal diameter of abdominal aortic aneurysm, the patients were divided into two groups: group A (diameter < 55 mm, n = 274) and group B (diameter > or = 55 mm, n = 155). The diameter of AAA, involvement of iliac artery, length, diameter and distortion of aneurismal neck in the two groups were recorded and compared retrospectively. Patients in group B were significantly older than group A (73.7 vs 71.1 years, P < 0.05). More patients in group B was complicated with coronary artery disease than those in group A (P < 0.05). The mean diameter of AAA in group A was (46.6 +/- 6.8) mm, and (66.8 +/- 11.2) mm in group B (P < 0.05). Proximal aneurysmal necks were shorter, wider and more tortuous in group B than those in group A (P < 0.05). Extraperitoneal approach, embolism of inner iliac artery and reconstruction of another inner iliac artery and stretch technique were more applied in group B. There were more endoleak during operation in group B and more stent-grafts were used. There was significant difference in morbidity rate between the two groups, while no statistic difference in mortality. And in group B, there were a high rate of endoleak and secondary intervention post operation. The diameter of AAA affects EVE and its results. In small aneurysms, EVE carries better outcome than in big aneurysms.

Staged endovascular stent grafts for concurrent mobile/ulcerated thrombi of thoracic and abdominal aorta causing recurrent spontaneous distal embolization

Mobile thrombus of the thoracic aorta is an uncommon pathology with potentially catastrophic complications. Recurrent spontaneous distal embolization may also occur from an ulcerated thrombus of the abdominal aorta. The simultaneous presence of a mobile thrombus in the thoracic aorta and ulcerated thrombus of the abdominal aorta is extremely rare and poses a significant treatment dilemma. Although various approaches have been reported, there is no standard treatment. Direct replacement of the thoracoabdominal aorta is extremely morbid, while continued embolization despite anticoagulation mandate intervention. We herein present the first case report of successful treatment of symptomatic mobile/ulcerated thrombi of the thoracic and abdominal aorta using staged endovascular stent graft repair. Successful treatment of the thoracic component with a thoracic aortic graft (TAG, Gore-Tex, W. L. Gore & Assoc., Flagstaff, Ariz.) was followed one week later by exclusion of the infrarenal aortic lesion with a bifurcated stent graft. Endovascular stent graft exclusion of mobile/ulcerated thoracic and abdominal aortic thrombi is a minimal invasive operation. It can be employed as an alternative procedure in treatment of aortic thrombus with embolization in high risk patients. Long-term follow-up will be necessary to assess the durability of this technique.

Endovascular Repair of Traumatic Superior Mesenteric Artery to Splenic Vein Fistula

Traumatic mesenteric arterioportal fistulas (APF) are rare but serious and life-threatening. This article reports the case of a 24-year-old female who suffered a gunshot wound to the abdomen and subsequently developed a superior mesenteric artery (SMA) pseudoaneurysm and APF, which caused secondary right heart failure and pulmonary hypertension. The patient underwent a successful endovascular stent-graft exclusion of the pseudoaneurysm/APF. The patient was asymptomatic 18 months post procedure and leading an active life with a normal arterial flow in the SMA confirmed by duplex ultrasonography.

Invited commentary

Invited commentary

Endovascular Exclusion of Popliteal Artery Aneurysms With Expanded Polytetrafluoroethylene Stent-Grafts: Early Results

There is increasing interest in using endovascular methods instead of surgical reconstruction to treat popliteal artery aneurysms. Exclusive use of the Viabahn stent-graft, a nitinol stent covered with expanded polytetrafluoroethylene, was assessed in the treatment of patients who presented with popliteal artery aneurysms in the absence of acute limb ischemia. Technical success, endoleaks, graft patency, freedom from amputation, and aneurysm sac flow and size changes were assessed by duplex ultrasound. From June 2004 to March 2006, 16 men (mean age, 76 years; range, 65-83) underwent endovascular exclusion of 23 popliteal artery aneurysms (mean diameter, 2.5 cm; range, 1.3-6.7 cm). Nine lesions had partial thrombus on preprocedural duplex imaging. Nineteen of the 23 limbs treated had at least 2-vessel tibial artery runoff. Procedures were performed under local anesthesia using ipsilateral percutaneous antegrade arterial access. All patients received 75 mg/day of clopidogrel afterward. Follow-up assessments included direct clinical examinations and duplex ultrasonography performed 1, 3, 6, and 12 months after the procedure. Primary patency and amputation-free survival were calculated using Kaplan-Meier analysis. Complete aneurysm exclusion (technical success) was achieved in all cases. During the mean follow-up of 7 months (range, 1-21 months), 22 of 23 treated limbs remained asymptomatic. One stent-graft thrombosis occurred 6 months after the procedure and was successfully treated with percutaneous mechanical thrombectomy, balloon angioplasty of a stent-graft stenosis, and insertion of an uncovered nitinol stent. No popliteal artery aneurysm sac size enlargements or endoleaks were detected. At 12 months, the treated limb mean ankle-brachial index was 1.0 (range, 0.82-1.31) and the primary and secondary patency rates were 93% and 100%, respectively. Early results with Viabahn endovascular stent-graft exclusion of asymptomatic popliteal artery aneurysms are promising. Patient selection for endovascular repair depends on suitable popliteal artery anatomy, extent of aneurysmal degeneration, and quality of tibial arterial runoff.

Percutaneous Endovascular Repair of Ruptured Abdominal Aortic Aneurysms

Percutaneous endovascular repair of ruptured abdominal aortic aneurysms (RAAAs) has better outcomes than traditional open surgical repair. Single-center retrospective review. University hospital tertiary referral center. Thirty-seven RAAAs treated using endovascular repair (n = 15) or open surgery (n = 22). From January 1, 2000, through December 31, 2005, 15 RAAAs were treated with endovascular stent graft exclusion using commercially available systems. Twenty-two other patients undergoing standard open surgical repair during the same interval comprised a control group for comparison. Early outcomes of percutaneous endovascular repair of RAAAs. Among the endovascular group, the mean +/- SD age was 73 +/- 9.8 years, 86.6% were men (n = 13), and 20.0% had a preoperative systolic blood pressure of 80 mm Hg or lower (n = 3). An entirely percutaneous procedure was performed in the final 11 patients using arterial closure systems. Technical success of attempted endovascular exclusion was 100.0%. The mean +/- SD procedure time (107 +/- 30 minutes), transfusion requirements (6.6 +/- 4.7 U), and length of stay (3.0 +/- 6.8 days) were statistically significantly reduced compared with open surgery. The 30-day mortality was 6.7% (1 of 15) compared with an open surgery 30-day mortality of 13.6% (3 of 22). No late complications (pseudoaneurysm, infection, lymphocele, or neuropathy) occurred after a completely percutaneous technique during a mean follow-up of 12 months. Percutaneous endovascular repair of RAAAs is a more expedient and less morbid alternative than open surgical repair.

Evaluation of pressure transmission and intra-aneurysmal contents after endovascular repair using the Trivascular Enovus expanded polytetrafluoroethylene stent graft in a canine model of abdominal aortic aneurysm

Endotension has been defined as persistently increased pressure within the excluded sac of an abdominal aortic aneurysm (AAA) resulting in increasing aneurysm size after endovascular repair in the absence of endoleak. Devices that use expanded polytetrafluoroethylene (ePTFE) have been associated with the development of endotension and continued AAA enlargement. In this study, intra-aneurysmal pressure and aneurysm content were evaluated after endovascular repair with the Enovus ePTFE stent graft in a canine model. Prosthetic ePTFE aneurysms, each containing a solid-state, strain-gauge pressure transducer, were implanted in the infrarenal aorta of 13 mongrel dogs (25-35 kg). A second pressure transducer was inserted into the native aorta for systemic arterial pressure measurement. The stent graft was then deployed to exclude the aneurysm via distal aortic access. Comparison was made among three distinct stent grafts: the Trivascular Enovus (nonporous ePTFE; four animals), the original Gore Excluder (porous ePTFE; five animals), and the Medtronic AneuRx (Dacron; four animals). Daily systemic and intra-AAA pressures were measured for 4 weeks. Intra-aneurysmal pressures were indexed to simultaneously measured systemic pressures. After 4 weeks, the aorta, the prosthetic aneurysm, and its contents were harvested, photographed, and processed for histologic investigation with hematoxylin and eosin and Masson trichrome staining. Within 24 hours after exclusion, the mean arterial pressure and pulse pressure within the AAA sac tapered to less than 20% of systemic pressure for all three stent graft types. Throughout the postoperative period, significantly lower indexed intra-aneurysmal pressures were present in the Enovus- and AneuRx-treated aneurysms as compared with those treated with the original Excluder stent graft (0.05 +/- 0.04, 0.16 +/- 0.06, and 0.06 +/- 0.03 for the Enovus, Excluder, and AneuRx, respectively). Histologic analysis of the Enovus-treated aneurysms demonstrated intraluminal content characterized almost entirely by erythrocytes and infrequent white blood cells without the fibrin organization-characteristics of acute or chronic thrombus. This contrasted with the content of the Excluder-treated aneurysms, which contained poorly organized fibrin deposition suggestive of acute thrombus, and of the AneuRx-treated aneurysms, which demonstrated mature, well-organized collagenous connective tissue. Exclusion of the AAA with the Enovus stent graft resulted in nearly complete elimination of intra-aneurysmal pressure in this model. Histologic analysis of the aneurysm content further suggested complete exclusion, including elimination of circulating clotting factors and fibroblasts responsible for thrombus formation and reorganization. Ultimately, clinical evaluation will be necessary to demonstrate the effectiveness of this stent graft in preventing the development of endotension.

Ruptured femoropopliteal artery aneurysms in von Recklinghausen neurofibromatosis

A 38-year-old woman with neurofibromatosis type 1 was referred for massive swelling of the left thigh, pain, and anemia. Angiography demonstrated three saccular aneurysms of the femoropopliteal artery. The largest measured 3 cm in diameter. Resection of the aneurysms and femoropopliteal interposition grafting using reversed saphenous vein was performed through a medial surgical approach. Arterial involvement in neurofibromatosis is a well known but infrequent occurrence. Stenotic lesions predominate. Aneurysmal defects are less common, and rupture of peripheral arteries is exceptional. Neurofibromatous invasion and dysplasia of the tunica media of the femoropopliteal vessel were confirmed by means of pathologic study. We think this is the second reported case of a femoropopliteal artery aneurysm and rupture associated with neurofibromatosis.

Acute Compartment Syndrome Related to Stent-Graft Exclusion of a Popliteal Arterial Aneurysm

The purpose of this morbidity and mortality case report is to discuss a characteristic of the Viabahn (W.L. Gore, Newark, DE) stent-graft deployment as well as a complication related to wire trauma during endovascular exclusion of a popliteal artery aneurysm. We encountered a phenomenon not described in the literature during deployment of a Viabahn stent graft. This necessitated further wire purchase, which resulted in perforation of a branch vessel within the calf. The rapid recognition of the clinical findings and prompt diagnosis of compartment syndrome was essential to early intervention, which prevented further complication and permanent sequelae.

Successful Covered Stent-Graft Exclusion of Carotid Artery Pseudo-aneurysm: Two Case Reports and Review of Literature

Postendarterectomy carotid artery pseudo-aneurysm (CPA) is a relatively infrequent complication with an estimated incidence of 0.3%-0.6%. A report from a single center experience on open-surgical repair of CPA has shown the associated high morbidity and mortality. Endovascular therapy is emerging as a safer alternative to open-surgical therapy. We describe two cases of CPA treated with commercially available Viabahn stent graft system (Gore AL, Flagstaff, AZ).

Influence of Severe Infrarenal Aortic Neck Angulation on Complications at the Proximal Neck Following Endovascular AAA Repair: A EUROSTAR Study

To examine the influence of severe infrarenal neck angulation (SNA) on complications after endovascular repair of abdominal aortic aneurysm (AAA). From October 1996 to January 2006, 5183 patients who underwent endovascular aneurysm repair using a Talent, Zenith, or Excluder stent-graft were enrolled into the EUROSTAR registry. Incidence of proximal type I endoleak, stent-graft migration, proximal neck dilatation, aneurysm rupture, secondary interventions, and all-cause and aneurysm-related mortality were compared between patients with and without severe infrarenal neck angulation (>60 degrees angle between the infrarenal aortic neck and the longitudinal axis of the aneurysm). In the short term (before discharge), proximal type I endoleak (OR 2.32, 95% CI 1.60 to 3.37, p<0.0001) and stent-graft migration (OR 2.17, 95% CI 1.20 to 3.91, p=0.0105) were observed more frequently in patients with SNA. Over the long term, higher incidences of proximal neck dilatation > or =4 mm (HR 1.26, 95% CI 1.11 to 1.43, p=0.0004), proximal type I endoleak (HR 1.80, 95% CI 1.25 to 2.58, p=0.0016), and need for secondary interventions (HR 1.29, 95% CI 1.00 to 1.67, p=0.0488) were seen in patients with SNA. All-cause mortality, aneurysm-related mortality, and rupture of the aneurysm were similar in patients with and without severe neck angulation. In the subgroup of patients with an Excluder endograft, proximal endoleak at the completion angiogram (OR 4.49, 95% CI 1.31 to 15.32, p=0.0166) and long-term proximal neck dilatation (HR 1.67, 95% CI 1.20 to 2.33, p=0.0026) were more frequently observed in patients with SNA. In the Zenith subgroup, proximal endoleak at the completion angiogram (OR 2.62, 95% CI 1.49 to 4.63, p=0.0009) and proximal stent-graft migration before discharge (OR 2.34, 95% CI 1.06 to 5.19, p=0.0353) were more common in patients with SNA. In the Talent subgroup, long-term proximal endoleak (HR 2.09, 95% CI 1.27 to 3.44, p=0.0036), proximal neck dilatation (HR 1.29, 95% CI 1.05 to 1.60, p=0.0168), and secondary interventions (HR 1.54, 95% CI 1.05 to 2.24, p=0.0259) were more frequently observed in patients with SNA. Severe infrarenal aortic neck angulation was clearly associated with proximal type I endoleak, while the relationship with stent-graft migration was not clear. Excluder, Zenith, and Talent stent-grafts perform well in patients with severe neck angulation, with only a few differences among devices.

Thoracic Stent Grafting for Acute Aortic Pathology

Elective endovascular repair of the thoracic aorta has shown reduced morbidity and mortality when compared with open surgery. The number of studies describing the use of thoracic endovascular stent grafts for acute pathology is limited, however. The purpose of this study was to describe our increasing experience with stent grafting for acute thoracic aortic pathology. Since January 2002, 28 patients underwent endovascular stent graft treatment for various types of acute thoracic aorta diseases, including complicated Stanford type B dissection (n = 12), ruptured descending aorta aneurysms (n = 7), intramural hematoma (n = 4), traumatic rupture of the thoracic aorta (n = 2), aortopulmonary fistula (n = 2), and penetrating aortic ulcer (n = 1). These acute thoracic aortic syndromes were predominantly localized in the proximal descending thoracic aorta (75%). Talent stent grafts were used in 26 patients and Excluder stent grafts in 2 patients. Stent graft deployment at the intended position was successful in all patients. There was 1 intraoperative death (3.6%), due to acute myocardial infarction, after successful exclusion of the lesion with a stent graft. Hospital mortality was 21.4% (n = 6). Four of 6 hospital deaths, however, were directly related to the severely compromised clinical status preoperatively, including extensive bowel ischemia and irreversible cerebral damage after resuscitation. New neurologic symptoms were seen in 4 patients. The majority of the neurologic symptoms improved and faded away during hospital stay. Mean follow-up was 11 months (range, 1 to 31), and all the hospital survivors (n = 22) were alive. There was 1 nonrelated stroke 4 months postoperatively. During follow-up, 2 patients required transposition of the left subclavian artery for malperfusion, and 2 patients required a second stent graft procedure for endoleak. Additionally, 2 patients with early type II endoleaks were treated conservatively, and 1 of them sealed spontaneously at 6 months. Thoracic stent grafting for acute aortic pathology is feasible in critically ill patients. Postoperative morbidity and mortality is predominantly related to the compromised preoperative clinical status, illustrating its use as salvage strategy.

Endovascular Aneurysm Repair Alters Renal Artery Movement: A Preliminary Evaluation Using Dynamic CTA

To observe the natural renal artery motion during cardiac cycles in patients with abdominal aortic aneurysm (AAA) and how the implantation of stent-grafts may distort this movement. Data on 29 renal arteries from 15 male patients (mean age 72.6 years, range 66-83) treated with Talent or Excluder stent-grafts were acquired using an electrocardiographically (ECG)-gated dynamic 64-slice CT scanner. ECG-triggered retrospective reconstructions were made at 8 equidistant time points over the R-R cardiac cycle. The gated datasets were reconstructed perpendicular to the center flow lumen of each renal artery at 1.2 and 2.4 cm from the renal ostium. Center of mass displacement was determined per cardiac cycle for pre- and post-EVAR renal arteries and compared. Normal renal artery motion in AAA patients was impressive, with up to 3-mm movement both near and distant from the aorta (mean 2.0+/-0.6 mm, range 1.1-3.0). EVAR inhibited proximal renal motion, resulting in a 31% decrease in maximal movement (mean 1.4+/-0.7 mm, range 0.7-2.0; p < or = 0.05). Distal renal artery motion was unaffected by EVAR, with motion similar to the pre-EVAR state. ECG-gated dynamic CTA is feasible on a 64-slice scanner with a standard radiation dose and can detect potentially serious consequences of EVAR. EVAR alters renal artery motion by limiting proximal motion while leaving distal motion unaffected.

Late type III endoleak from graft erosion of an Excluder stent graft: A case report

We report a case of a late type III endoleak from a hole in the expanded polytetrafluoroethylene graft material of an Excluder bifurcated stent-graft approximately 12 months after implantation. The endoleak was successfully repaired by relining the defect site with an Excluder iliac limb. To our knowledge, this is the first reported case of late graft-material related Type III endoleak involving the Excluder device.

Open stent-grafting: aborted procedure in a patient with mega aorta syndrome

Open stent-grafting is a recent technical modification of endoluminal stent-grafting, in which a stent-graft is inserted into the descending thoracic aorta through an opening in the aortic arch, to treat distal arch aneurysms or aortic dissection. Controversy remains as to whether patients with mega aorta syndrome, or those with very wide aneurysm necks, could be candidates for stent-graft treatment--open or endoluminal. We recently attempted open stent-grafting in a patient with mega aorta syndrome who had a distal aortic arch aneurysm. A previous attempt at surgical resection of the aneurysm through left thoracotomy ended in failure because of severe adhesion in the left lung. This time, we planned total arch replacement with open stent-graft exclusion of the aneurysm. However, open stent-grafting had to be abandoned intraoperatively due to technical difficulties as well as our lack of experience with such difficult cases. Conventional total arch replacement with elephant trunk was performed instead. Due to its deep location, the distal neck of the aneurysm could not be reached through median sternotomy and, therefore, the distal aortic anastomosis was performed within the aneurysm cavity. Thus, the distal portion of the aneurysm was not excluded from circulation. The future treatment plan in the present case is further complicated by the fact that a second-stage surgery through left thoracotomy will not be possible. Conventional total arch replacement proved rather inappropriate as a treatment strategy in the present case. Open stent-grafting might have been a more useful approach is spite of the challenges posed by the aneurysm. There needs to be a consensus as to whether patients with mega aorta syndrome or those with very wide aneurysm necks could be candidates for stent-graft treatment--open or endoluminal in difficult circumstances.

The development of endotension is associated with increased transmission of pressure and serous components in porous expanded polytetrafluoroethylene stent-grafts: Characterization using a canine model

This study used a canine model of abdominal aortic aneurysms (AAAs) to compare intra-aneurysmal pressure and thrombus formation after exclusion with Dacron and expanded polytetrafluoroethylene (ePTFE) stent-grafts. Prosthetic AAAs with implanted strain-gauge pressure transducers were treated by stent-graft exclusion using Food and Drug Administration-approved devices in 10 mongrel dogs: five Dacron (AneuRx) and five ePTFE (original Excluder). Intra-aneurysmal pressure was measured over 4 weeks after AAA exclusion and indexed to the systemic pressure, represented as a percentage of a simultaneously obtained systemic pressure (value = 1.0). Magnetic resonance imaging (MRI) of the intra-aneurysmal thrombus was performed at 1, 2, and 4 weeks after exclusion and expressed as a signal-to-noise ratio (S:N) to control for background signal intensity. Comparisons of pressures and S:N between the two stent-grafts was analyzed with the Student's t test. Intra-aneurysmal thrombus was characterized histologically. In animals excluded with both Dacron and ePTFE stent-grafts, the intra-aneurysmal pressure was nonpulsatile and reduced to <30% of systemic pressure. Significantly greater pressure transmission was observed after AAA exclusion using ePTFE compared with Dacron stent grafts (systolic pressure: ePTFE, 0.28 +/- 0.12 vs Dacron, 0.11 +/- 0.02, P < .001; mean pressure: ePTFE, 0.16 +/- 0.08 vs Dacron, 0.06 +/- 0.02, P < .001). MRI confirmed the absence of perfusion in all aneurysms. The T1-weighted signal intensity remained persistently elevated (S:N at 1 week, 2.7 +/- 0.4 vs 2 weeks, 4.0 +/- 0.2 vs 4 weeks, 5.4 +/- 1.3) in ePTFE-treated intra-aneurysmal thrombus, suggesting an absence of thrombus organization. In contrast, progressive evolution of T1 signal intensity in aneurysms excluded by Dacron stent-grafts was consistent with maturation from intact red blood cells (S:N at 1 week, 3.3 +/- 0.4) to methemoglobin (S:N at 2 weeks, 6.1 +/- 0.8), and then hemosiderin and ferritin (S:N at 4 weeks, 2.4 +/- 0.5). Histologically, ePTFE-excluded aneurysms contained poorly organized thrombus with red blood cell fragments and haphazardly arranged fibrin deposition indicative of active remodeling and continued influx of transudated serum. In aneurysms excluded by Dacron stent-grafts, dense, mature collagenous connective tissue and organized fibrin were present, indicative of greater thrombus organization. Stent-graft treatment reduces intra-aneurysmal pressure to <30% of systemic pressure when no endoleak is present; however, significantly greater pressure is present in aneurysms treated with porous ePTFE stent-grafts than Dacron grafts. Histologic and MRI imaging analysis suggest that active transudation of serous blood components may be contributing to this increased intra-aneurysmal pressure.

Midterm clinical success and behavior of the aneurysm sac after endovascular AAA repair with the Excluder graft

Recent studies have reported different sac behavior after endovascular repair of abdominal aortic aneurysms, depending on the endografts. This study was designed to evaluate mid-term outcome and sac behavior after treatment with the Gore Excluder stent-graft. Between June 1999 and January 2005, 109 selected patients with suitable anatomy were treated electively for abdominal aortic aneurysm with the Excluder stent graft. Data were prospectively collected in a computerised database and included demographics, details of the aortoiliac anatomy, procedural and clinical success, and postoperative complications. Postoperative sac size and the presence of endoleaks were assessed with computed tomography scans obtained at 1, 6, and 12 months, and yearly thereafter. All diameter measures in patients followed for > 1 year (84.4%) were analyzed. Assisted primary technical success was achieved in 108 cases (99.1%). No type I endoleaks and 12 (11.1%) type II endoleaks were recorded < or = 1 month from the procedure. Mean follow-up was 29.6 +/- 16.1 months. We recorded one new-onset type IA endoleak, complete resolution of five type II endoleaks, and eight new-onset type II endoleaks. The overall prevalence of type II endoleaks was 14%. Shrinkage at 1, 2, 3, and 4 years was observed in 20.7%, 30.5%, 38.9%, and 36.8% of cases. The presence of type II endoleak influenced the trend of aneurysm size throughout the 4 years. Aneurysms without endoleak shrank more than aneurysms with type II endoleak (P < .0001). We observed two cases of sac enlargement due to the presence of endoleaks. No cases of endotension with sac enlargement, late open conversion, or aneurysm-related deaths were observed. Unchanged aneurysmal sacs remained stable during follow-up, with no adverse events. Endovascular treatment with the Excluder device in selected patients produces low rates of shrinkage, but this peculiar sac behavior does not affect mid-term clinical success.