First-generation Stent-grafts Research Articles

Overall outcome after endovascular aneurysm repair with a first-generation stent graft (Vanguard): A 20-year single-center experience

ObjectiveThe problems with first-generation stent grafts for endovascular aneurysm repair are well known, but their long-term outcome remains to be established. The purpose of the study was to characterize the outcome of patients treated for abdominal aortic aneurysm (AAA) with a first-generation stent graft, Vanguard (Boston Scientific, Natick, Mass), in a single academic center with a follow-up of up to 20 years. MethodsThere were 48 AAA patients electively treated with a Vanguard stent graft between February 1997 and November 1999. The patients were monitored annually until the end of 2018. The outcomes were overall survival and the number of graft-related complications and reinterventions. ResultsThe mean age was 70 years (range, 54-85 years), and the mean follow-up was 107 months (range, 6-262 months). All stent grafts were successfully implanted, but 90% of the patients encountered graft-related complications during follow-up. The most common complications were endoleaks (type I, 27%; type II, 29%; type III, 31%), stent fracture (46%), graft thrombosis (31%), and migration (40%). A total of 40 (83%) patients required a secondary procedure during long-term follow-up. The endovascular method for treating the complication was successful in 73 (87%) of 84 cases. There were no primary conversions, but 10 patients (21%) required a late conversion. In five cases, the complications required relining with a newer device. There were four AAA ruptures (8.3%), two of them fatal. The cumulative overall survival rates were 94%, 69%, 33%, 15%, and 13% at 1 year, 5 years, 10 years, 15 years, and 20 years, respectively. ConclusionsThe use of the Vanguard, a first-generation stent graft, was associated with multiple graft-related complications. However, these complications could mainly be treated by endovascular means. The Vanguard stent graft is a good example of how new technology can cause unpredictable problems that can magnify the workload and endanger the patient's well-being even decades after the initial procedure.

A 15-Year Single-Center Experience of Endovascular Repair for Elective and Ruptured Abdominal Aortic Aneurysms

Purpose: To evaluate the differences in technical outcomes and secondary interventions between elective endovascular aneurysm repair (el-EVAR) procedures and those for ruptured aneurysms (r-EVAR). Methods: Of the 906 patients treated with primary EVAR from September 1998 until July 2012, 43 cases were excluded owing to the use of first-generation stent-grafts. Among the remaining 863 patients, 773 (89.6%) patients (mean age 72 years; 697 men) with asymptomatic or symptomatic abdominal aortic aneurysms (AAAs) were assigned to the el-EVAR group; 90 (10.4%) patients (mean age 73 years; 73 men) were assigned to the r-EVAR group based on blood outside the aortic wall on preoperative imaging. The primary study outcome was technical success; secondary endpoints, including freedom from secondary interventions and late survival, were examined with Kaplan-Meier analyses. Results: At baseline, r-EVAR patients had larger aneurysms on average (p<0.001) compared to el-EVAR patients. Technical success was comparable (p=0.052), but there were more type Ia endoleaks at completion angiography in the r-EVAR group (p=0.038). As anticipated, more patients died in the first month in the r-EVAR group (18.9% vs 2.2% el-EVAR, p<0.001). At 5 years, there was an overall survival of 65.1% for the el-EVAR patients vs 48.1% in the r-EVAR group (p<0.001). The freedom from AAA-related mortality was 95.7% for el-EVAR and 71.0% for r-EVAR (p<0.001). Five-year freedom from type I/III endoleaks was significantly lower in the r-EVAR group (78.7% vs 90.0%, p=0.003). Five-year freedom from secondary intervention estimates were not significantly different (el-EVAR 84.2% vs r-EVAR 78.2%, p=0.064). Conclusion: Within our cohort of primary EVAR patients, r-EVAR cases showed comparable stent-graft–related technical outcome. Although there was a higher incidence of type Ia endoleaks on completion angiography in the r-EVAR group, the overall secondary intervention rate was comparable to el-EVAR.

Acute Traumatic Thoracic Aortic Injury: Considerations and Reflections on the Endovascular Aneurysm Repair.

Traumatic rupture of the thoracic aorta is a life-threatening lesion and it occurs in 10 to 30% of fatalities from blunt thoracic trauma and is the second most common cause of death after head injury. Immediate surgery is often characterized by a high mortality and morbidity rate. Delayed repair of traumatic aortic injuries has significant survival benefits and a much lower mortality rate compared with early open repair. Despite developments in operative techniques, there still remains considerable operative mortality and morbidity associated with a surgical approach even if delayed. Endovascular stent grafts for the thoracic aorta represents an alternative to the conventional approach for traumatic aortic rupture. Because of the lower invasivity avoiding thoracotomy and use of heparin, endovascular repair can be applied in acute patients without the risk of destabilizing pulmonary, head or abdominal traumatic lesions. However, despite the good deal of convincing evidence for endovascular treatment for thoracic aortic diseases and for traumatic aortic injuries as a valid and efficacious alternative to surgery, several reports show a variety of late complications of thoracic endografts especially for first-generation stent-grafts. In light of this, is the endovascular treatment really safe, efficacious and free from complications in the long term? This manuscript aims to offer a moment of reflection on this important chapter of aortic pathology.

Impact of Stent-Graft Development on Outcome of Endovascular Repair of Acute Traumatic Transection of the Thoracic Aorta

To analyze the impact of stent-graft design on the outcome of endovascular repair of acute traumatic thoracic aortic transection. Forty-eight patients (38 men; mean age 37 ± 11 years) underwent endovascular repair for an acute traumatic aortic rupture between April 2001 and March 2011. Up to October 2007, 32 patients (mean age 41 ± 16 years; group 1) were treated with the first generation of commercially available thoracic stent-grafts (10 Talent, 20 Excluder/TAG, 2 Zenith). From November 2007, 16 patients (mean age 42 ± 19 years; group 2) were treated with second-generation thoracic stent-grafts (13 Valiant and 3 C-TAG). The 2 groups were statistically comparable. Follow-up computed tomography was performed at 1 week; at 3 and 6 months; and annually thereafter. In the 2 groups, the mortality rate related to aortic repair was nil. All the patients have completed each of their scheduled follow-up evaluations and CT scans. The morbidity rate was significantly reduced (p = 0.0003) from 18.7% (first generation) to 6.2% (second generation). Type I endoleak (n = 1), inadvertent coverage of the supra-aortic trunks (n = 3), and stent-graft collapse (n = 2) occurred only with the first-generation stent-grafts. One iliac artery rupture occurred with a second-generation stent-graft. Enhanced stent-graft conformability and more accurate delivery systems have significantly decreased the morbidity of endovascular repair of acute traumatic transection of the thoracic aorta. The increasing clinical experience may also have contributed to improved results.

Complete ten-year follow-up after endovascular abdominal aortic aneurysm repair: Survival and causes of death

To analyze the hazard and causes of death after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms during a complete ten year follow-up. This is a retrospective clinical study of 130 consecutive patients undergoing EVAR between 1995 and 1998. One-hundred twenty-one patients (93.1%) were treated with first-generation stentgrafts and nine patients (6.9%) received second-generation devices. All patients completed a follow-up of at least 10 years, unless death occurred before then. Time and causes of death were provided by the Austrian central register of deaths. The median follow-up was 7.6 years, and the 130 patients had 968.5 person-years of follow-up. The ten-year mortality rate was 62.3%. Cardiovascular events were the most frequent causes of death, with a 3.9 incidence rate per 100 person-years. Cancer death and death due to other causes occurred in 2.1 and 1.8 cases per 100 person-years, respectively. Lethal late aneurysm rupture happened in 4.6% (n=6), which corresponds to an annual incidence rate of 0.6 per 100 person-years. All of those patients had been treated with first-generation devices. Cardiovascular events were the most frequent cause of death after EVAR, followed by malignancy and other diseases. The risk of dying from secondary rupture was clearly lower than that of death due to other reasons during ten years after EVAR, even in patients with first-generation stentgrafts.

Early Elective Conversion for Failing Evar

The aim of the study was to assess the long term results of endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms at the Helsinki University Central Hospital 1996-2004 with a special emphasis on elective conversion procedures and their outcome. Treatment results and follow-up data of all 110 elective EVAR procedures performed in our institution were gathered prospectively and evaluated. Conversion to open surgery was performed in 23 (21%) of 110 EVAR patients. 30-day mortality after elective stent-graft deployment was 0% as it was also on elective conversions (n = 20). Secondary elective conversions were performed due to infection in two and after failing stent-graft treatment in 12 patients. Six of the conversions were performed primarily. Three urgent conversions (3% overall) were performed: two of these patients died, corresponding to an overall mortality of 9% (2/23) in all conversions. Five-year aneurysm-related mortality after EVAR among patients with elective conversion was 0% and 19% in patients with secondary procedures other than elective conversions. As conversions seem to be hazardous only when performed in urgent situations, elective conversion could be an alternative treatment method in complex failing first-generation stent-grafts as it may reduce mortality associated with urgent conversions or repeated attempts to maintain graft integrity with endovascular procedures.

Midterm results of endovascular repair of descending thoracic aortic aneurysms with first-generation stent grafts

Objective Five years after reporting our initial stent-graft repair of descending thoracic aortic aneurysms experience, we determined the 5- to 10-year results of stent-graft treatment and identified risk factors for adverse late outcomes. Methods Between 1992 and 1997, 103 patients (mean age 69 ± 12 years) underwent repair using first-generation (custom-fabricated) stent grafts. Sixty-two patients (60%) were unsuitable candidates for conventional open surgical repair (“inoperable”). Follow-up was 100% complete (mean 4.5 ± 2.5 years; maximum 10 years). Outcome variables included death and treatment failure (endoleak, aortic rupture, reintervention, and/or aortic-related or sudden death). Results Overall actuarial survival was 82% ± 4%, 49% ± 5%, and 27% ± 6% at 1, 5, and 8 years. Survival in open surgical candidates was 93% ± 4% and 78% ± 6% and at 1 and 5 years compared with 74% ± 6% and 31% ± 6% in those deemed inoperable ( P < .001). Independent risk factors for death were older age (hazard ratio = 1.1; P = .008), previous stroke (hazard ratio = 2.8; P = .003), and being designated an inoperable candidate (hazard ratio = 1.9; P = .04). Actuarial freedom from aortic reintervention and treatment failure at 8 years was 70% ± 6% and 39% ± 8%, respectively. Earlier operative year (hazard ratio = 1.2; P = .07), larger distal landing zone diameter (hazard ratio = 1.1; P = .001), and transposition of the left subclavian artery (hazard ratio = 3.3; P = .008) were determinants of treatment failure. Conclusions Survival after aneurysm repair using crude, first-generation stent grafts was satisfactory in good operative candidates but bleak in the inoperable cohort, raising the question of whether asymptomatic patients should have even been treated. Late aortic complications were detected in many patients, reemphasizing the importance of serial imaging surveillance.

Endovascular Placement of a Nitinol–ePTFE Stent-Graft for Abdominal Aortic Aneurysms: Initial and Midterm Results

Because first-generation stent-grafts did not meet initial expectations, a recently designed nitinol-expanded polytetrafluoroethylene (ePTFE) stent-graft was tested for treatment of abdominal aortic aneurysms (AAAs) in a prospective clinical study. The primary study endpoints were technical success and safety. A nitinol-ePTFE self-expandable stent-graft (Excluder) was used to treat 72 patients with AAAs. The median follow-up period was 21.5 months +/- 13 (range, 1-46 mo). Primary technical success in accurate placement of the device was achieved in 70 of 72 patients (97%). Complete exclusion of the aneurysm from arterial flow was achieved in 57 of 72 patients (79.2%). Three type I leaks were observed during implantation and were immediately corrected with a proximal cuff prosthesis in two patients. Fourteen of 72 patients (19.4%) had a type II leak. Major complications were observed in three patients (4.1%), including one death in the early postinterventional period (one of 72, 1.4%). At 3 months, aneurysms were excluded in 70 of 71 patients (98.6%), and at 12 months, aneurysms were occluded in 29 of 30 patients (96.7%). The maximum diameter of the aneurysm decreased from 55 mm +/- 11 (median +/- SD) before intervention to 53 mm +/- 13 at 6 and 12 months. None of the patients showed aneurysm growth. This newly designed stent-graft proved to be effective and safe for treatment of AAAs.

The evolution of Z stent–based stent-grafts for endovascular aneurysm repair:

The purpose of this study was to analyze the impact of stent-graft design and operator skills on outcomes after endovascular abdominal aortic aneurysm repair. One hundred sixty-four patients (mean age 71 years) underwent stent-graft repair. Patients were treated with four different types of stent-graft: first-generation (n = 58) and second-generation (n = 17) Ivancev-Malmö monoiliac stent-grafts (IM I and IM II, respectively) combined with femoral-femoral crossover, Chuter bifurcated stent-graft (n = 15), and the Zenith stent-graft (n = 74). Patients underwent digital subtraction angiography and contrast CT preoperatively and were then followed with CT scans postoperatively. Recently, followup was changed to CT scanning at 1 month and 1 year postoperatively and annually thereafter. Ultrasonographic duplex scanning substitutes in the remaining followup. Changes in aneurysm diameters and occurrence of endoleaks were recorded. Short- and midterm mortality and complications and postoperative secondary interventions were recorded, and life-table analysis for intervention-free stent-graft survival was calculated. Immediate and late conversions and 30-day mortality were reduced for second- (IM II and Zenith) compared with first-generation stent-grafts (IM I and Chuter). Stent-graft migrations occurred only with the IM I and Chuter stent-grafts. Type I endoleak was significantly more common in first-generation stent-grafts. First-generation stent-grafts required significantly more secondary interventions than second-generation stent-grafts up to 30 months postoperatively. Enhanced stent-graft design has improved the probability of stent-graft success after endovascular abdominal aortic aneurysm repair. Better technical skills and increased use of intraoperative adjunctive procedures may also have contributed to improved results.