Treatment of aortoiliac aneurysms with use of single-piece tapered stent-grafts

Restrictive bare stent prevents distal stent graft-induced new entry in endovascular repair of type B aortic dissection

OBJECTIVE

Distal stent graft-induced new entry (SINE) can occur after thoracic endovascular aortic repair (TEVAR) of type B aortic dissection. This study investigated the mechanism of distal SINE and its prevention using a restrictive bare stent (RBS) technique.

METHODS

From January 2013 to December 2014, 68 consecutive type B aortic dissection patients received endovascular repair at our center. The RBS technique was used with distal oversizing (between the diameter of the thoracic stent graft and the descending aorta true lumen diameter at the level of the intended distal edge of the thoracic stent graft) >20%.

RESULTS

Twenty-three patients received TEVAR with a single thoracic stent graft (TEVAR group, n = 23); the rest received TEVAR combined with the RBS technique (TEVAR + RBS group, n = 45). Four distal SINEs occurred in the TEVAR group. Distal oversizing (69.7% ± 35.5% vs 31.2% ± 24.5%; P = .005) and expansion mismatch ratio (132.2% ± 16.9% vs 106.5% ± 11.6%; P < .05) were significantly higher in the SINE patients. Compared with standard TEVAR, TEVAR + RBS was associated with significantly lower distal oversizing (TEVAR vs TEVAR + RBS group, 59.8% ± 24.7% vs 16.7% ± 7.6%; P < .05), lower expansion mismatch ratio (113.8% ± 14.6% vs 103.8% ± 11.7%; P = .012), and lower distal SINE rate (4/23 [17.4%] vs 0/45 [0%]; P = .011). Compared with the TEVAR group, the false lumen was reduced significantly at the level of the RBS distal edge (P = .029).

CONCLUSIONS

Excessive distal oversizing and distal expansion mismatch ratio may contribute to the occurrence of distal SINE. The RBS technique reduced the incidence of distal SINE. Based on our midterm and long-term observations, implantation of an RBS may improve aortic remodeling.

Application of protective stents in endovascular repair of acute complicated Stanford type B aortic dissections

PURPOSE

To describe the use of protective stents in the endovascular repair of acute complicated Stanford type B aortic dissections.

METHODS

From 2009 to 2011, 33 patients (27 men; mean age 47 years, range 31-73) with acute complicated Stanford type B aortic dissection underwent thoracic endovascular aortic repair (TEVAR) assisted by protective stents. In all cases, the proximal and distal landing zones differed in size by >5 mm, and the primary entry tear was in the proximal descending aorta. A bare self-expanding stent (protective stent) was deployed initially at the intended distal landing site of the primary stent-graft in the true lumen. The intention was that the bare stent would prevent excessive dilation of the distal end of the stent-graft in the vicinity of the entry tear, thus avoiding intimal rupture.

RESULTS

Successful stent deployment and sealing of the entry tear was achieved in all patients. The median diameter and length of the protective bare stents was 20.3 mm (range 18-24) and 72.7 mm (range 60-80), respectively, while the corresponding dimensions of the covered stent-grafts were 32.8 mm (range 26-40) and 157.4 mm (range 120-200 mm), respectively. There was no stent twisting, migration, of rupture of the false or true lumen. Computed tomography 1 week postoperatively demonstrated closure of the primary entry tear with thrombosis of the false lumen in all cases. No patients were lost to follow-up, which has ranged from 3 months to 3 years. No late endoleaks or stent complications, such as angulation, dislodgment, persistent leaks, branch obstruction, or stent-graft migration, have been observed, and there has been no chronic progressive true or false lumen dilatation, recurrences, or deaths.

CONCLUSION

Adjunctive use of a protective stent when treating acute Stanford type B aortic dissections in which the diameters of the proximal and distal landing zones differ by >5 mm is feasible and safe and provides good short-term outcomes.

Systematic Review and Meta-analysis of 12 Years of Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

Endovascular repair (ER) of abdominal aortic aneurysm (AAA) is a new technique, and reported rates of endoleak, conversion to open repair, rupture and mortality vary widely. The aim of this study was to estimate these rates from the published data, and examine how this has changed as more patients have undergone ER.

METHODS

A systematic review and meta-analysis of publications identified through searches of the electronic databases EMBASE and Medline. All publications quoting endoleak, conversion to open repair, rupture and mortality rates for a series of patients undergoing ER were included.

RESULTS

163 studies pertaining to 28,862 patients undergoing ER were identified as relevant for the review and meta-analysis. The pooled estimate for operative mortality was 3.3% (95% confidence interval 2.9 to 3.6%). The pooled estimate for type 1 endoleaks was 10.5% (95% confidence interval 9.0 to 12.1%), with an annual rate of 8.4% (95% confidence interval 5.7% to 12.2%). The pooled estimate of type 2,3 and 4 endoleaks was 13.7% (95% confidence interval 12.3 to 15.3%), with an annual rate of 10.2% (95% confidence interval 7.4% to 14.1%). The pooled estimate for primary conversion to open repair was 3.8% (95% confidence interval 3.2 to 4.4%), and for secondary conversion to open repair 3.4% (95% confidence interval 2.8 to 4.2%). The pooled estimate for post-operative rupture was 1.3% (95% confidence interval 1.1 to 1.7%), with an annual rupture rate of 0.6% (95% confidence interval 0.5% to 0.8%). Multivariate meta-regression analysis showed that rates of operative mortality, post-operative rupture and total number of endoleaks all fell significantly (p<0.05) over time.

CONCLUSIONS

This study demonstrates a low mortality and a gradual reduction in vascular morbidity and mortality associated with endovascular repair since it was first introduced.

Endovascular treatment of abdominal aortic aneurysms--6 years of experience with Ella stent-graft system

PURPOSE

Evaluation of 6-year results of abdominal aortic aneurysm (AAA) treatment by Ella stent-grafts with regard to safety and effectivity in relation to morphology of the aneurysm.

METHODS

From a group of 172 patients with AAA, in whom elective endovascular treatment was considered, 120 of them (69.8%) were found to be suitable for this type of therapy. The bifurcated type of stent-graft was implanted in 97 patients, uniiliacal type in 19 patients and only four patients were found to be suitable for tubular type of stent-graft. Additional necessary procedures (internal iliac artery occlusion or contralateral common iliac artery occlusion in a group of patients with uniiliacal type of stent-graft) were performed surgically during the stent-graft implantation. CT and US controls were performed at 3, 6 and 12 months after implantation, later every 12 months.

RESULTS

Primary technical success was achieved in 109 of the 120 patients (91%). Primary endoleak was recorded in 11 patients (primary endoleak type Ia in seven patients, type Ib in three patients and type IIIa in one patient). Assisted technical success after reintervention or spontaneous seal was 98.3%. Surgical conversion was indicated in two patients (1.7%). Perioperative mortality rate was 3.3%. Total average follow-up period was 20.7 months (range from 2 to 60 months). In nine patients (7.5%) secondary endoleak type II was found at control CT or US, in three patients partial thrombosis of the stent-graft was found. There was no aneurysm rupture during follow-up.

CONCLUSION

Treatment of AAA with Ella stent-graft system is effective and safe. Bifurcated stent-graft is the most frequently used type. Uniiliacal type of stent-graft is used by us only in cases of complicated morphology.

Early vascular complications after endovascular repair of aortoiliac aneurysms

The purpose of this study was to estimate the frequency of and review the treatment options for intraoperative endograft access-related vascular complications and early postoperative vascular complications of endovascular repair for aortoiliac aneuryms (EVAR). Between February 1998 and April 2000, 53 patients (46 males, 7 females) with aneurysms of the abdominal aorta (AAA) and iliac arteries were treated with endovascular grafts (48 AAA, and 5 iliac aneurysms). All procedures were performed using open exposure of the femoral arteries. One patient with an AAA was converted to open repair (primary technical success, 98.1%). We recorded the need for adjunctive vascular procedures or intervention to the access arteries (iliofemoral) or the endograft because of thrombosis or distal embolization. Events were classified as either intraoperative, early postoperative (< 30 postoperative days), or late postoperative. Their etiology and treatment were recorded. The results were compared to those from other series reported in the literature and to published registry data. From our results we concluded that the need for adjunctive vascular procedures to the iliofemoral arteries at the time of EVAR is significant. These procedures are necessary to either repair damage to the access arteries from the delivery system or provide a conduit for graft delivery in cases where the access arteries are inadequate. Early postoperative vascular complications are due to technical factors resulting in residual graft limb stenoses. Both intraoperative and early postoperative vascular complications after EVAR are more common in female patients. These complications can be effectively treated with a variety of open surgical and transfemoral endovascular techniques.

Internal iliac artery embolization before endovascular repair of abdominal aortic aneurysms: frequency, efficacy, and clinical results

OBJECTIVE

The aim of our study was to assess the frequency, efficacy, and incidence of adverse effects of internal iliac artery embolization.

MATERIALS AND METHODS

Of 343 patients examined for stent-graft repair, 147 were suitable for endovascular treatment. Fifty-five patients underwent preprocedural embolization of the internal iliac artery either unilaterally (46 patients) or bilaterally (nine patients). Successful embolization was assessed angiographically and with helical CT follow-up examinations. Colonic ischemia was ruled out clinically or colonoscopically. Buttock claudication, and sexual dysfunction in men, were evaluated through a questionnaire.

RESULTS

Embolization of the internal iliac artery increased by 16% the percentage of patients for whom endovascular repair was suitable. After successful embolization in all patients, routine CT follow-up examinations after a mean time of 16.7 months showed no evidence of endoleaks related to retrograde perfusion via embolized internal iliac arteries. Nevertheless, in all patients who had undergone embolization, a primary endoleak was detected in 43.4% at the first postoperative CT examination. None of our patients had evidence of colonic ischemia. Clinical follow-up data of 46 patients were available. Of these patients, mild to severe new onset buttock claudication was found in 13 (36.1%) of 36 patients with unilateral, and in eight (80%) of 10 patients with bilateral, internal iliac artery embolization (p = 0.03). Five (25%) of 20 men had an erectile dysfunction after the procedure.

CONCLUSION

Embolization of the internal iliac artery is a safe and efficient procedure that increases the applicability for endovascular repair of aortoiliac aneurysms. However, buttock claudication and erectile dysfunction are a drawback in a substantial number of patients.

Analysis of initial CT findings after endovascular repair of abdominal aortic aneurysm

PURPOSE

To determine the spectrum and frequency of specific computed tomographic (CT) findings in the acute period after endovascular repair of abdominal aortic aneurysm (AAA).

MATERIALS AND METHODS

CT images obtained 1--3 days after endograft placement were evaluated in 88 patients. The images were analyzed for stent position, appearance of endograft components, perigraft leak, and postoperative findings including air and acute thrombus within the aneurysm and air surrounding the femoral-femoral bypass graft. Findings that could be misinterpreted as perigraft leak were evaluated.

RESULTS

Fifteen (17%) of 88 patients had perigraft leak in the acute postoperative period. The bare segment of the proximal self-expanding stent covered one or both renal arteries in 54 (61%) patients. One patient had CT evidence of renovascular compromise. Postoperative air was within the aneurysmal sac in 51 (58%) patients and surrounded the femoral-femoral bypass graft in 67 (94%) of 71 patients in whom the grafts were evaluated with CT. Mottled attenuation within the aneurysmal sac was seen in 50 (57%) patients. Forty-six (52%) patients had calcifications within longstanding thrombus. In 31 (35%) patients, findings that could have been misinterpreted as perigraft leak were identified.

CONCLUSION

Accurate analysis of CT findings after endovascular AAA repair requires careful review of all available CT images (preprocedural and pre- and postcontrast) and clear understanding of specific stent-graft components and placement.

Balloon-expandable common iliac artery occluder device for endovascular aneurysm repair

This study was performed to evaluate the efficacy of a balloon-expandable Palmaz stent common iliac artery occluder device for endovascular stent-graft repair of aortoiliac aneurysms. Eighty-four patients (79 men, 5 women; age range 60-95 yr; mean age, 76 yr) with aortoiliac aneurysms underwent endovascular stent-graft repair. The repair consisted of a stent-graft extending from the abdominal aorta to the iliac or common femoral artery, a cross-femoral bypass graft, and an endovascular arterial occluder device within the contralateral common iliac artery. The occluder device consisted of a 5-cm segment of 6-mm diameter polytetrafluoroethylene (PTFE) graft with a purse-string suture occluding the leading end and a Palmaz stent sutured to the trailing end. The occluder device was delivered through a 17F catheter via an arteriotomy. Eighty-three of the 84 patients received aortic endografts. In one case, infrarenal aortic rupture occurred during deployment of the aortic stent requiring conversion to an open surgical repair. Initial technical success for occluder device insertion was achieved in 78 of the remaining 83 patients. Failure to advance the occluder device delivery sheath through a diseased iliac artery occurred in one patient. Common iliac artery rupture occurred during balloon expansion and occluder device deployment in two patients. Two patients required additional coil embolization of the common iliac artery adjacent to the occluder device at the time of stent-graft insertion to correct incomplete iliac occlusion. Delayed occluder device-related complications included one patient with a postoperative iliac endoleak who required percutaneous coil embolization and one patient with a postoperative iliac endoleak in whom a contained aortic aneurysm rupture developed that was treated by surgical ligation of the common iliac artery. Use of the Palmaz stent-based iliac artery occluder device is an effective technique to induce common iliac artery thrombosis to facilitate endoluminal stent-graft aneurysm repair.

Accuracy of plastic replica of aortic aneurysm using 3D-CT data for transluminal stent-grafting: experimental and clinical evaluation

PURPOSE

To plan stent-grafting for aortic aneurysms with complicated morphology, we prepared life-sized aortic replicas by laser stereolithography using helical 3D--CT data. The accuracy of the replica was evaluated by measurement of vessel phantoms and clinical 3D--CT data.

METHOD

An imaginary aortic wall was created from helical CT images of the aorta, and a hollow plastic replica was produced by laser stereolithography. The accuracy of the replica was evaluated in five abdominal aortic aneurysms by experimental phantom studies and measurements of the replicas.

RESULTS

The mean difference in measurements between 3D--CT images and model vessels and between 3D--CT images and aortic replicas was 0.2 mm each. Therefore, the difference in measurements between real aortic aneurysms and the replicas was at most 0.4 mm.

CONCLUSION

The accuracy of the replica is satisfactory, making it useful for preoperative evaluation and simulation for stent-grafting.

Dilatation of stent-grafts by luminal pressures: experimental evaluation of polytetrafluoroethylene (PTFE) and woven polyester grafts

PURPOSE

To evaluate the effect on dilatation of three types of covering materials used for endovascular stent-grafts.

METHODS

Stent-grafts with three types of covering material [0.1-mm polytetrafluoroethylene (PTFE), 0.2-mm PTFE, and 0.15-mm woven polyester] were placed in a fluid circuit. For the pulsatile pressure test, the luminal pressure of 190/130 mmHg was loaded up to 300,000 pulses. For the static pressure test, the luminal pressure was increased from 50 to 300 mmHg at 50-mmHg increments. The percent of dilatation of each stent-graft was compared.

RESULTS

The 0.1-mm PTFE stent-graft was significantly more dilated than the 0.2-mm PTFE and the 0.15-mm woven polyester stent-graft (p < 0.005) in both examinations. There was no significant difference between the 0.2-mm PTFE and the 0.15-mm woven polyester stent-grafts. The dilatation of the 0.1-mm PTFE stent-graft was irreversible.

CONCLUSION

The 0.15-mm woven polyester and the 0.2-mm PTFE stent-grafts may be preferable to the 0.1-mm PTFE stent-graft with regard to dilatation and deformity.

Short-term (30-day) outcome of endovascular treatment of abdominal aortic aneurism: results from the prospective Registry of Endovascular Treatment of Abdominal Aortic Aneurism (RETA)

OBJECTIVES

to assess the early morbidity and mortality of a new treatment, the endovascular repair of abdominal aortic aneurysms, during its introduction into clinical practice.

DESIGN

a prospective voluntary registry collecting demographic and risk factor data, details of aneurysm morphology, procedure performed, immediate and 30-day outcomes.

SETTING

thirty-one U.K. centres performing endovascular repair submitted data.

RESULTS

six hundred and eleven cases were registered in three years of data collection (January 1996 to December 1998). Four per cent of patients received an aortic tube device, 60% an aorto-bi-iliac device and 36% an aorto-uni-iliac device and a crossover graft (AUIC). Conversion to open repair was required in 5% of cases, with more conversions in the AUIC group (OR 2.9 (95% CI: 1.3-6.4)p=0.01). Post procedure complications occurred in 25% of cases. Unfit patients had significantly more complications than fit patients (35% vs 20% for fit patients (OR 1.8 (95% CI: 1.2-2.7)p=0.007)). At 30 days aneurysms were excluded in 90% of cases. Endoleaks were more common in larger aneurysms (2% if aneurysms were <6 cm in diameter vs 10% if >6 cm, OR 5.6 (95% CI: 2.1-14.9)p=0.0006). The overall mortality was 7% but was significantly higher for AUIC devices, (4% for combined aortic tube and bi-iliac devices (AT/BI) vs 12%, OR 2.6 (95% CI: 1.2-5.9 p=0.018)), and unfit patients (4% for fit patients vs 18%, OR 4.3 (95% CI: 2.0-9.5)p<0.001).

CONCLUSIONS

endovascular repair is feasible with short-term outcomes comparable to those of conventional surgical repair. In unfit patients the possible benefit in life expectancy gain must be balanced against the morbidity and mortality of the procedure.

Utility and reliability of endovascular aortouniiliac with femorofemoral crossover graft for aortoiliac aneurysmal disease

OBJECTIVE

The purpose of this study was to determine the early efficacy of endovascular aortouniiliac stent grafts with femorofemoral bypass graft in the treatment of aortoiliac aneurysmal disease.

METHODS

We analyzed 51 consecutive patients from January 1997 to March 1999 with a mean follow-up of 15.8 months. Patients ranged in age from 44 to 93 years (mean, 75 years) with a mean aortic aneurysm diameter of 6.2 cm. Technical success was achieved in 50 patients; one patient required conversion to open repair intraoperatively. We placed 28 custom-made and 22 commercial devices. The mean operative time was 223 minutes. The endograft was extended to the external iliac artery in 42% of cases. The contralateral common iliac artery was occluded using either a closed covered stent or intraluminal coils.

RESULTS

The median hospital stay was 4 days with an average intensive care unit stay of 0.25 days. There were no operative mortalities. Two patients died during follow-up from unrelated conditions. Endoleaks occurred in 11 patients (22%); seven patients (14%) required intervention (four catheter based, three operative). Other complications occurred in 38% of patients but were largely remote or wound related. One femorofemoral bypass graft occluded immediately postoperatively as a result of an intraprocedural external iliac dissection yielding a 98% primary patency and 100% secondary patency. Clinical success was achieved in 88% of patients.

CONCLUSIONS

These data suggest that this strategy represents a reliable method of repair of aortoiliac aneurysmal disease and extends the capability of an endoluminal approach to patients with complex iliac anatomy.

Internal iliac artery embolization in the stent-graft treatment of aortoiliac aneurysms: analysis of outcomes and complications

PURPOSE

To analyze the complications of internal iliac artery (IIA) embolization in conjunction with stent-graft treatment of aortoiliac aneurysms.

MATERIALS AND METHODS

Seventy-one patients with aortoiliac (n = 47) or iliac (n = 24) aneurysms were treated with endoluminal placement of stent-grafts. Thirty-two patients (31 men, one woman; mean age, 73 years; range, 56-88 years) had embolization or occlusion of one (n = 27) or both (n = 5) IIAs. Status of the IIAs and the collateral circulation was assessed by retrospective review of angiographic images. Follow-up consisted of a standardized patient questionnaire and review of radiologic and medical records.

RESULTS

The mean follow-up time was 35 months (range, 5-64 months). Eleven of the 47 patients with abdominal aortic aneurysms (AAA) (23%) and 19 of the 24 patients with iliac aneurysms (79%) required IIA embolization. One patient with AAA and another with iliac aneurysm had unintentional occlusion of an IIA by extension of the stent-graft over their origins. A total of seven patients had bilateral occlusion of the IIAs after the procedure. Additionally, the inferior mesenteric arteries (IMAs) of two other patients with AAA were also embolized. In six patients, all three vessels were occluded after placement of the stent-grafts. Symptoms were reported in nine of the 20 (45%) patients with iliac aneurysms and in three of the 12 (25%) patients with AAA. Symptoms consisted of buttock claudication (nine of 32, 28%), new sexual dysfunction (two of 16, 12%), and transient urinary retention (3%). Seven of the claudicants had resolution of symptoms after a mean interval of 14 months (range, 1-36 months). There were no instances of bowel ischemia, neurologic sequelae, or buttock necrosis related to these procedures.

CONCLUSION

Embolization of the IIA is associated with symptoms in a significant number of patients. While symptoms are transient in most patients, they can be problematic. Efforts should be made to preserve the pelvic circulation if possible.

Endovascular repair of abdominal aortic aneurysms: where do we stand?

Endovascular repair of abdominal aortic aneurysms has evolved dramatically within the past few years. In light of the potential to reduce morbidity and mortality associated with open surgical repair, endoluminal grafting offers therapeutic options to patients who are not surgical candidates because of comorbidities. With the development of bifurcated devices, more complex aneurysms may be treated by endovascular grafting. Although successful placement of endovascular grafts requires a pronounced learning curve, including appropriate patient selection, midterm results seem consistent with those of traditional open repair of aneurysms. This review describes the current indications, minimal requirements, different devices and associated techniques, and potential complications of endoluminal repair of abdominal aortic aneurysms. Future aspects of endoluminal grafting are also discussed.

Embolotherapy of persistent endoleaks after endovascular repair of abdominal aortic aneurysm with the ancure-endovascular technologies endograft system

PURPOSE

Endoleak is a potential complication after endovascular repair of abdominal aortic aneurysm (AAA). It may result in continued growth of the aneurysm and potentially result in aneurysm rupture. The authors present their experience with embolotherapy in patients with persistent perigraft flow treated with the Ancure-Endovascular Technologies endograft system.

MATERIALS AND METHODS

Between February 1996 and August 1998, 54 patients underwent successful repair of AAA with use of the Ancure system. All underwent operative angiography and discharge computed tomography (CT). Follow-up included CT at 6, 12, and 24 months, and CT was also performed at 3 months if an endoleak was present on the discharge CT. Persistent endoleak was defined as perigraft flow still present on the 6-month CT. Seven of 21 initial endoleaks persisted at 6 months. Six patients returned for embolization of the perigraft space and outflow vessels including lumbar arteries and the inferior mesenteric artery (IMA).

RESULTS

Five of the six patients had leaks from the proximal (n = 1) or distal attachment sites (n = 4) of the Ancure system with outflow into lumbar arteries and/or the IMA; one leak was caused by retrograde IMA flow. The six patients underwent nine embolization procedures with only one minor complication. Follow-up CT showed complete resolution of endoleak and decrease in size of the aneurysm sac in all patients.

CONCLUSIONS

Although endoleak is commonly seen initially with the Ancure system, persistent leak occurred in 13% of the patients in the study. Persistent flow in most patients arises from a graft attachment site combined with patent outflow vessels such as the IMA or lumbar arteries. Persistent endoleaks can be effectively and safely embolized with use of a combination of coil embolization of the perigraft space and embolization of outflow vessels. Such intervention resulted in a decrease in size of the aneurysm sac.

Custom bifurcated stent-graft for abdominal aortic aneurysms: initial experience

PURPOSE

To describe a custom bifurcated stent-graft for possible treatment of abdominal aortic aneurysm (AAA).

MATERIALS AND METHODS

Five male patients (mean age, 76 +/- 6 years), who had AAA (mean diameter, 4.7 +/- 0.4 cm) and who were considered to be at high risk for conventional surgery, were treated with a custom modular bifurcated stent-graft constructed with bifurcated 24-mm x 12-mm (upper body diameter x iliac limb diameter) Cooley Veri-Soft Woven polyester grafts and Gianturco-Rösch Z stents. The stent-graft body was delivered through 20-22-F sheaths, and the contralateral iliac limb was delivered through a 16-F sheath by means of surgical exposure of the common femoral arteries. A flared distal limb extender (12 mm to 14 mm) was created for one patient to accommodate a large common iliac artery.

RESULTS

Stent-grafts were successfully deployed without complications in all five patients. There were no proximal or distal leaks. A lumbar-to-inferior mesenteric artery leak was seen in one patient at 24 hours. At 6-month follow-up, all devices were intact, with complete exclusion and shrinkage of the aneurysm in four of five patients. Aneurysm size remained stable in the one patient with a lumbar-to-inferior mesenteric artery leak.

CONCLUSION

A custom, bifurcated stent-graft was utilized for endovascular treatment of AAA. Long-term follow-up is necessary for the device.