A Percutaneous Technique for Preservation of Arch Branch Patency During Thoracic Endovascular Aortic Repair (TEVAR):Retrograde Catheterization and Stenting

PURPOSE

To report a percutaneous endovascular technique to deal with stent-graft encroachment and coverage (partial or total) of the origin of the left common carotid artery (CCA) or the left subclavian artery during thoracic endovascular aortic repair.

TECHNIQUE

Percutaneous retrograde puncture of the left CCA was accomplished with guidewire advancement into the ascending aorta and insertion of a 6-F sheath. Balloon angioplasty and deployment of a stent across the origin of the left CCA successfully recanalized the vessel and restored normal antegrade flow and pressure. It was reasoned that the stent would maintain vessel patency by focally displacing the endograft device, preventing partial or total coverage (and obstruction) of the arch branch origin. This technique has been used successfully in 8 patients, 6 involving the left CCA and 2 the left subclavian artery. Two of the patients were lost to follow-up after 6 and 12 months. The other 6 patients have been followed from 10 to 32 months; the stented vessels have remained patent in all.

CONCLUSION

While the "interposition" of a bare metal stent between a thoracic endograft and the aortic wall is theoretically unappealing and potentially detrimental, as the direct interaction between the devices might undermine the integrity of one or both, we have not seen such problems in this limited clinical experience.

Carotid artery stenting with emboli protection surveillance study: Thirty-day results of the CASES-PMS study

OBJECTIVE

This study examined whether physicians with varying carotid stent experience would obtain safety and efficacy outcomes as good as those from the pivotal SAPPHIRE trial following participation in a comprehensive carotid stent training program.

BACKGROUND

This study was performed as a condition of approval study for the PRECISE(R) Nitinol Stent and the ANGIOGUARD XP Emboli Capture Guidewire.

METHODS

Patients at high surgical risk who were either symptomatic with >or=50% stenosis or asymptomatic with >or=80% stenosis of the common or internal carotid artery received carotid artery stenting with distal emboli protection using the PRECISE Nitinol Stent and the ANGIOGUARD XP Emboli Capture Guidewire. Physicians were qualified based on either prior experience in carotid stenting with the ANGIOGUARD XP Emboli Capture Guidewire or following participation in a formal training program. The primary endpoint of major adverse events (MAE) at 30 days (death, myocardial infarction (MI), or stroke) was tested for non-inferiority compared with an objective performance criterion (OPC) of 6.3% established from the stent cohort of the SAPPHIRE trial.

RESULTS

The 30-day MAE rate was 5.0%, meeting the criteria for non-inferiority to the prespecified OPC (95% CI [3.9%, 6.2%] P<0.001). Asymptomatic patients (N=1,158, 78.2%) had similar outcomes to the overall results (MAE 4.7%). Outcomes were similar across levels of physician experience, carotid stent volume, geographic location, presence/absence of training program.

CONCLUSIONS

Utilizing a comprehensive training program, carotid artery stenting by operators with differing experience in a variety of practice settings yielded safety and efficacy outcomes similar to those reported in the SAPPHIRE trial.

Will carotid stenting eclipse carotid endarterectomy and, if so, when and how?

Treatment of carotid artery stenosis to prevent stroke ranks amongst the most significant roles for vascular surgeons and specialists as a whole. Carotid endarterectomy (CEA) is the acknowledged standard of care, and is based on solid scientific evidence. However, its pedestal position has been challenged on several fronts, mainly because approximately 20% of such operations are performed on patients who may be at high-risk for poor outcomes (or higher than usual complications) owing to unfavorable factors related to anatomical and/or medical comorbidity factors. Additionally, and as attitudes towards less invasion reach the carotid territory, CEA is increasingly viewed with some suspicion (and even disdain) by those who glorify everything endovascular simply for being so. The result is that percutaneous carotid-stent intervention has evolved into a formidable competitor to CEA. But it will not have a free ride. While it is arguably true that the high-risk territory has been conquered by carotid angioplasty stenting (CAS), the bulk of the CEA market remains unaffected. Treatment of nonhigh-risk patients with CAS remains highly controversial and essentially unproven, especially for those who are asymptomatic. CEA remains the only intervention whose application is based on level 1 evidence. Thus, it would be fair to say that rise of CAS to domination has a long way to go.

Endovascular Repair of the Thoracic Aorta: Lessons Learned

BACKGROUND

Available information on outcome and best strategies for thoracic endovascular repair is somewhat limited and unclear. We sought to gain a better understanding of these issues through a retrospective review of our 8-year clinical experience in the treatment of thoracic aortic aneurysms and dissections.

METHODS

A retrospective chart review of 186 patients undergoing stent-graft repair of thoracic aortic lesions at our institution during the 92-month period ending on December 31, 2004 was performed. Patients were divided into two groups based on the indication for treatment; group A had thoracic aortic aneurysms (TAA) and group B had type B aortic dissections (TBAD). Both groups were analyzed for outcome variables including technical success, mortality, major morbidity, endoleak rate and type, secondary endovascular interventions, and long-term survival. Mean follow-up was 40 months (range, 1 to 92 months).

RESULTS

Compared to group B, group A patients were older and had a higher incidence of peripheral vascular disease and chronic obstructive pulmonary disease. Sixty percent of all patients were American Society of Anesthesiologists class III and the remainder were class IV (38.3%) and V (1.7%). The procedure was completed in 180 patients (96.7%), with all 6 failures being access-related. The average procedure time was 149 minutes (range, 72 to 405). The 30-day mortality was 4.7% (9 patients), and serious morbidity was 19.9% (37 patients). Eight patients (4.3%) developed spinal cord ischemia, 4 immediately after the procedure and 4 delayed (1 to 3 days). Total hospital length of stay averaged 6.7 days. Secondary endovascular interventions were successful in 17 patients with angiographically confirmed endoleaks (type I and III). At an average follow-up of 40 months, freedom from all-cause mortality was 62.5% in group A and 58.1% in group B.

CONCLUSIONS

Stent-graft repair for TAA and TBAD can be achieved with high technical success and comparatively low rates of morbidity and mortality. Midterm survival appears to be favorable. Further refinements in device technology and procedural techniques are needed.

Endograft repair of acute aortic dissection. Promises and challenges

Acute dissection is a uniquely complex, relatively common, and frequently lethal aortic catastrophe. Historically, surgical treatment has been reserved for cases with complications including rupture; the results have been less than optimal because of excessive morbidity and mortality. This is the main reason why conservative management emerged as the standard of care for management of acute type B aortic dissection (TBAD). While more patients would appear to survive with a conservative treatment strategy, the outcome in terms of 30-day mortality (20%) and occurrence of late complications - such as enlarging aneurysms of the thoracic false lumen (30-40%) - leaves (again) much to be desired. Stent-graft endovascular repair has emerged as a very promising, less invasive treatment option. These devices, when used appropriately, can achieve the important therapeutic goals of entry-site coverage, depressurization of the false lumen, and expansion of the compressed true lumen - overcoming ischemic (malperfusion) manifestations. The early results of stent-graft repair of TBAD are encouraging, and even exciting, but much more work needs to be done in various critical areas surrounding this condition. Thoracic endograft technology has lagged behind its abdominal counterpart. The design of acute dissection-specific devices is imperative, reflecting the significant differences between TBAD and degenerative thoracic aortic aneurysm disease. Needs for this and other important developments notwithstanding, it is generally acknowledged that stent-graft intervention does represent an important advance in the treatment of patients with TBAD. Well-designed, controlled clinical trials will be necessary to elucidate the relative value of several endovascular thoracic strategies.

Suprarenal endograft fixation avoids adverse outcomes associated with aortic neck angulation

The advent of endovascular therapy has had a profound impact on repair of abdominal aortic aneurysms (AAA). Prudent patient selection, particularly in regard to unfavorable anatomy, is emerging as perhaps the most important determinant of endovascular abdominal aortic aneurysm repair (EVAR) outcome. The aim of this study was to examine the association of one such anatomic factor, proximal aortic neck angulation, with the incidence of adverse events following EVAR. Prospectively collected data on 289 EVAR repairs with the Talent endograft (Medtronic, Inc., Minneapolis, MN) from March 1998 to June 2000 were analyzed. Stent graft-specific adverse events studied were migration, endoleak, kinking, thrombosis, and AAA expansion. Computed tomography (CT) scanning with three-dimensional post-processing and/or aortography was used to measure aortic neck angle. Patients were categorized into one of four groups according to their neck angle: I (0-10 degrees); II (11-39 degrees); III (40-59 degrees); or IV (60-85 degrees). Outcomes were evaluated by chi-squared analysis and ANOVA. There was a direct correlation between AAA diameter and neck angle (p = 0.002). There was no difference in endoleak rate (p = 0.877), stent migration (p = 0.850), or AAA expansion rate (p = 0.599) between groups. Device kinking >45 degrees was associated with neck angulation > or = 60 degrees (p = 0.013), but not with other adverse outcomes. The average neck angle was 30 degrees in patients with endoleaks and 31 degrees in patients without endoleaks. Increasing aortic neck angulation was not associated with the selected adverse outcomes within 1 year following EVAR with the Talent stent graft using suprarenal fixation with the exception of graft kinking. This may be related to the graft design that permits suprarenal aortic fixatiou of the proximal stent graft, Whether severe degrees of angulation of 60 degrees or greater can be safely treated with suprarenal fixation requires further study.

Suprarenal Endograft Fixation Avoids Adverse Outcomes Associated with Aortic Neck Angulation

The advent of endovascular therapy has had a profound impact on repair of abdominal aortic aneurysms (AAA). Prudent patient selection, particularly in regard to unfavorable anatomy, is emerging as perhaps the most important determinant of endovascular abdominal aortic aneurysm repair (EVAR) outcome. The aim of this study was to examine the association of one such anatomic factor, proximal aortic neck angulation, with the incidence of adverse events following EVAR. Prospectively collected data on 289 EVAR repairs with the Talent endograft (Medtronic, Inc., Minneapolis, MN) from March 1998 to June 2000 were analyzed. Stent graft-specific adverse events studied were migration, endoleak, kinking, thrombosis, and AAA expansion. Computed tomography (CT) scanning with three-dimensional post-processing and/or aortography was used to measure aortic neck angle. Patients were categorized into one of four groups according to their neck angle: I (0-10 degrees); II (11-39 degrees); III (40-59 degrees); or IV (60-85 degrees). Outcomes were evaluated by chi-squared analysis and ANOVA. There was a direct correlation between AAA diameter and neck angle (p = 0.002). There was no difference in endoleak rate (p = 0.877), stent migration (p = 0.850), or AAA expansion rate (p = 0.599) between groups. Device kinking >45 degrees was associated with neck angulation > or = 60 degrees (p = 0.013), but not with other adverse outcomes. The average neck angle was 30 degrees in patients with endoleaks and 31 degrees in patients without endoleaks. Increasing aortic neck angulation was not associated with the selected adverse outcomes within 1 year following EVAR with the Talent stent graft using suprarenal fixation with the exception of graft kinking. This may be related to the graft design that permits suprarenal aortic fixatiou of the proximal stent graft, Whether severe degrees of angulation of 60 degrees or greater can be safely treated with suprarenal fixation requires further study.

Endovascular Repair of Nontraumatic Ruptured Thoracic Aortic Pathologies

Endovascular repair of ruptured infrarenal abdominal aortic aneurysms (AAA) is receiving increased attention as the number of experienced users increases. Development of thoracic aortic stent grafts has lagged behind infrarenal advancements because of the reported prevalence of disease. In a few centers, however, the experience in performing thoracic stent graft procedures is quite substantial, such that endovascular therapy has been applied to ruptured thoracic aortic pathologies even though data remain limited and this novel therapy remains controversial. We report our combined experience with endovascular repair of ruptured thoracic aneurysms (RTA) and ruptured thoracic dissections (RTD). One hundred eighty-four thoracic stent graft procedures at the University of North Carolina (UNC) and Union Memorial Hospital (UMH) were reviewed and those patients undergoing RTA or RTD repair from January 1, 2000 to December 31, 2003 identified. Patients having procedures for elective repair or aortic transections were excluded from the analysis. Patient presentation, preoperative condition, procedural variables, mortality, and morbidity were examined. Seventy-four percent of the collective procedures were undertaken in high-risk patients (UNC, 38 of 40; UMH, 99 of 144). Twenty-two patients (8.7%; UNC, n = 6; UMH, n = 16) underwent treatment for either an RTA (n = 11) or an RTD (n = 11). The average age of this cohort was 66.5 +/- 15.6 years and the average aneurysm diameter was 73.1 +/- 31.4 mm. The mean duration of symptoms prior to repair was 103.1 +/- 122 hr, influenced primarily by transport times and device availability. Stent graft exclusion was accomplished in 100% of patients with a procedural mortality of 0%. Commercial Talent devices were used in 19 patients (86.4%) and AneuRx device was used in 1 patient (4.5%). In the remaining two (9.1%) patients hand-made devices constructed of Gianturco stents and Dacron fabric were used because of active hemorrhage and lack of appropriate device sizes. Operative time was 135.5 +/- 48.5 min and was associated with an average blood loss of 242.0 +/- 232.4 cc. Thirty-day mortality was 45.5% (RTA, 27.3%; RTD, 63.6%; p = 0.099). Length of stay in the intensive care unit was 6.1 +/- 7.9 days and the mean hospital stay was 11.7 +/- 10.6 days. Major complications were present in 54.5% of RTA (cardiac, 1; pulmonary, 3; cardiovascular accident, 2; spinal cord ischemia, 2; pulmonary embolism, 1), and 81.2% of RTD (multisystem organ failure, 7; pulmonary, 1; common femoral artery injury, 1) but not statistically different between groups. There were only two late complications (cardiac death, endoleak-Ia, 1) that occurred during the mean follow-up of 12.5 +/- 11.3 (range, 1-32) months. These results indicate that endovascular repair of ruptured thoracic pathologies can be accomplished with an acceptable morbidity and mortality. There were no immediate procedural mortalities and complete exclusion was accomplished in all patients. Most postoperative complications arose from preexisting medical conditions and were not procedure related. The benefit of endovascular repair of ruptured thoracic aortic pathologies is promising.

Post-Endograft Abdominal Aortic Aneurysm Shrinkage Varies Among Hospitals:Observations From Multicenter Trials

PURPOSE

To evaluate differences in abdominal aortic aneurysm (AAA) shrinkage among hospitals following protocol-driven patient selection and using endografts from a single manufacturer.

METHODS

Standardized inclusion criteria for the Talent endograft multicenter trials included AAA diameter >/=40 mm and proximal neck limits of length >/=5 mm, diameter 14 to 32 mm, and angle </=60 degrees. AAA reporting standards categories were used to classify distal aorta and common iliac artery involvement. Serial computed tomographic scans through 12-month follow-up were examined by independent core laboratory review. Significant shrinkage was defined as a >/=5-mm decrease in the AAA largest minor axis diameter. Trial sites with >10 complete study cases were selected for stepwise logistic regression analysis. In the 13 trial sites meeting this criterion, 323 patients (mean age 74; 93% men) were treated for aneurysms with a mean pretreatment diameter of 53 mm.

RESULTS

At 12 months, significant AAA shrinkage occurred in 192 (59%) cases. The AAA shrinkage rate was 71% to 82% at 3 sites, 60% to 64% at 4 sites, 45% to 50% at 4 sites, and 35% and 27% at the 2 remaining sites. In the multivariate analysis, the hospital site showed a strong, independent association with aneurysm shrinkage (p<0.04). Neck and pretreatment AAA diameters were also found to be important factors (p<0.04). Age, gender, AAA classification, neck length, and angle were not significant correlates. Sixty-four (20%) endoleaks (29 type I, 34 type II, and 1 type III) were observed. The incidence of proximal endoleak was significantly different among sites (p<0.001) and highest in the 3 sites with the lowest AAA shrinkage rate.

CONCLUSIONS

AAA shrinkage rates vary significantly among hospitals using the same endograft and protocol-defined patient selection criteria. Site-specific factors appear to be an important variable leading to successful endograft repair, as defined by post-endograft aneurysm shrinkage.

Carotid stenting with a new system for distal embolic protection and stenting in high-risk patients: The carotid revascularization with ev3 arterial technology evolution (CREATE) feasibility trial

The purpose of this study was to evaluate the feasibility of carotid artery revascularization using a new system for carotid stenting and distal embolic protection in 30 patients with severe carotid stenosis and high risk for carotid endarterectomy (Carotid Revascularization With ev3 Arterial Technology Evolution, or CREATE). Previous studies suggest that patients with carotid stenosis and serious comorbid cardiopulmonary and anatomic conditions are at high risk for carotid endarterectomy. All patients underwent percutaneous revascularization using the Protégé GPS self-expanding nitinol stent (ev3, Plymouth, MN) and the Spider distal embolic protection system (ev3). In-hospital and 30-day outcomes were analyzed. High-risk features included age > 75 years (63%), left ventricular ejection fraction < 35% (20%), and restenosis after prior carotid endarterectomy (53%). Procedural success was 100%. In-hospital complications included severe vasovagal reactions in six patients (20%) and a popliteal embolus in one patient (3.3%), treated by successful embolectomy. During 30 days of follow-up, two patients (6.6%) experienced minor neurological deficits, including transient expressive aphasia that resolved without therapy in one patient and homonymous hemianopsia due to contralateral posterior circulation stroke in one patient. This study supports the feasibility of percutaneous carotid artery revascularization with the Protégé GPS self-expanding stent and Spider distal embolic protection system, which will be evaluated in a large multicenter pivotal trial (CREATE Pivotal Trial).