Risk Factors, Dynamics, and Clinical Consequences of Aortic Neck Dilatation after Standard Endovascular Aneurysm Repair.

OBJECTIVE: Aortic neck dilatation (AND) occurs after endovascular aneurysm repair (EVAR) with self expanding stent grafts (SESs). Whether it continues, ultimately exceeding the endograft diameter leading to abdominal aortic aneurysm (AAA) rupture, remains uncertain. Dynamics, risk factors, and clinical relevance of AND were investigated after EVAR with standard SESs. METHODS: All intact EVAR patients treated from 2000 to 2015 at a tertiary institution were included. Demographic, anatomical, and device related characteristics were investigated as risk factors for AND. Outer to outer diameters were measured at a single standardised aortic level on reconstructed computed tomography (CT) images. RESULTS: A total of 460 patients were included (median follow up 5.2 years, interquartile range [IQR] 3.0, 7.7 years; CT imaging follow up 3.3 years, IQR 1.3, 5.4). Baseline neck diameter was 24 mm (IQR 22, 26) and increased 11.1% (IQR 1.5%, 21.9%) at last CT imaging. Endograft oversizing was 20.0% (IQR 13.6, 28.0). AND was greater during the first year (5.2% [IQR 0, 11.7]) decreasing subsequently (two to four years to 1.4%/year [IQR 0.0, 4.5%], p ≤ .001) and was associated with suprarenal fixation endografts (t value = 7.9, p < .001) and oversizing (t value = 4.4, p < .001). AND exceeding the endograft was 3.5% (95% CI 2.2% - 4.8%) and 14.4% (95% CI 11.0% - 17.8%) at five and eight years, respectively. Excessive AND was associated with baseline neck diameter (OR 1.2/mm, 95% CI 1.05 - 1.41) while the Excluder endograft had a protective effect (OR 0.15, 95% CI 0.04 - 0.58). Excessive AND was associated with type 1A endoleak (HR 3.3, 95% CI 1.1 - 9.7) and endograft migration > 5 mm (HR 3.1, 95% CI 1.4 - 6.9). CONCLUSION: AND after EVAR with SES is associated with endograft oversizing and radial force but decelerates after the first post-operative year. Baseline aortic neck diameter and suprarenal stent bearing endografts were associated with an increased risk of AND beyond nominal stent graft diameter. However, it remains unclear whether patient selection, differences in endograft radial force or the suprarenal stent are accountable for this difference.

Long-term results after standard endovascular aneurysm repair with the Endurant and Excluder stent grafts.

OBJECTIVE: Many endografts are currently available for standard endovascular repair of infrarenal abdominal aortic aneurysms. Comparison of long-term outcomes between devices might aid in this decision process, but comparative data are scarce. The purpose of this study was to report long-term clinical outcomes of two commercially available endoprosthesis, the Endurant (Medtronic Vascular, Inc, Minneapolis, Minn) and the Excluder (W. L. Gore & Associates, Flagstaff, Ariz) stent grafts. METHODS: Patients undergoing standard endovascular repair from July 2004 to December 2011 in a single institution with the Endurant or the Low-Porosity Excluder endografts were eligible. Only patients treated for intact degenerative abdominal infrarenal aneurysms were included. All measurements were performed on center-lumen line reconstructions obtained on dedicated software. The primary end point was primary clinical success, defined as clinical success without the need for an additional or secondary surgical or endovascular procedure. Neck-related events (a composite of type IA endoleak, neck-related secondary intervention, or migration of >5 mm), neck morphology changes, renal function, and overall survival were secondary end points. RESULTS: The study included 277 patients (156 Endurants; 121 Excluders). The median follow-up was 5.8 years (range, 0.1-12.4 years) and did not differ between groups (P = .18). Patients treated with the Endurant stent graft had wider (neck diameter of >28 mm, 27.3% vs 1.7% [P < .001]; neck diameter of 27 mm, [interquartile range (IQR), 24-29 mm] for Endurant and 24 mm [IQR, 22-25 mm] for Excluder; P < .001) and more angulated necks (ß-angle of >60°, 26.7% vs 12.5%; P = .004). Oversizing was greater in the Endurant group (16% [IQR, 12%-22%] vs 13% [IQR, 8%-17%], respectively; P < .001). Patients were treated outside device instructions for use regarding proximal neck: 16.7% in the Endurant and 17.3% in the Excluder group (P = .720). The 7-year primary clinical success was 54.7% for the Endurant and 58.1% for the Excluder groups (P = .53). Freedom from neck-related events at 7 years was 76.7% for the Endurant and 78.8% for Excluder group (P = .94). The Endurant stent graft (hazard ratio [HR], 2.7; 95% confidence interval [CI], 1.3-5.8; P = .009) was an independent predictor of significant renal function decline. Neck dilatation was greater in Endurant-implanted patients (13% [95% CI, 2%-22%] vs 4% [95% CI, 0%-10%]; P < .001). Overall survival at 7 years was 61.4% in the Endurant and 50.3% (n = 50; standard error, 0.047) in the Excluder group (P = .39). CONCLUSIONS: This study reveals that durable and sustainable results can be obtained with either of these late generation devices. This finding suggests that careful planning and a tailored device selection taking into account the patient's anatomy are more relevant determinants than the graft model itself to obtain clinical success. The Endurant endoprosthesis seems to be associated with a higher rate of neck dilatation and faster decrease in the estimated glomerular filtration rate, but further studies with longer follow-up are necessary to determine the clinical relevance of these findings.

Comparison of midterm results of endovascular aneurysm repair for ruptured and elective abdominal aortic aneurysms.

OBJECTIVE: Endovascular aneurysm repair (EVAR) became an increasingly preferred modality for abdominal aortic aneurysm (AAA) repair both in elective AAA repair (el-EVAR) and EVAR of a ruptured AAA (r-EVAR) setting. Ruptured AAAs usually have more hostile anatomies and less time for planning. Consequently, more complications may arise after r-EVAR. The purpose of this study was to compare mi-term outcomes between r-EVAR and el-EVAR. METHODS: A retrospective cohort analysis of patients undergoing EVAR from 2000 to 2015 at a tertiary institution was performed. Patients with previous aortic surgery, nonatherosclerotic AAA and isolated iliac aneurysms were excluded. In-hospital casualties or patients who were intraoperatively converted to open repair were also excluded. For the midterm outcome analysis, only patients with at least two postoperative examinations (a 30-day computed tomography scan and a second postoperative examination performed 6 months or later) were considered. The primary end point was freedom from aneurysm-related complications (a composite of type I or III endoleak, aneurysm sac growth, migration of more than 5 mm, device integrity failure, AAA-related death, late postimplant rupture, or AAA-related secondary intervention). Freedom from secondary interventions, neck-related events (defined as a composite of type IA endoleak, migration of more than 5 mm, or preemptive neck-related secondary intervention) and late survival were secondary end points. The impact of device instructions for use (IFU) compliance on neck events was also assessed. RESULTS: The study included 565 patients (65 r-EVAR and 500 el-EVAR). Eighty-two patients were treated outside proximal neck IFU, 13 in the r-EVAR group (21.3%) and 69 (14.5%) in the el-EVAR (P = .16). During the index hospitalization, there were more complications (12.3% vs 3.2%; P = .001) and reinterventions (12.3% vs 2.8%; P < .001) in the r-EVAR group. After discharge, median clinical follow-up time was 4.3 years (interquartile range, 2.1-7.0 years) without differences between both groups. Five-year freedom from AAA-related complications was 53.9% in the r-EVAR group and 65.4% in the el-EVAR (P = .21). In multivariable analysis the r-EVAR group was not at increased risk for late complications (hazard ratio [HR], 0.94; 95% confidence interval [CI], 0.54-1.61; P = .81). Five-year freedom from neck-related events was 74% in r-EVAR and 82% in the el-EVAR group (P = .345). Patients treated outside neck IFU were at greater risk for neck-related events both in r-EVAR (HR, 6.5; 95% CI, 1.8-22.9; P = .004) and el-EVAR group (HR, 2.6; 95% CI, 1.5-4.5; P < .001). Freedom from secondary interventions at 5 years was 63.0% for r-EVAR and 76.9% for el-EVAR (P = .16). Survival at 5 years was 68.8% in the r-EVAR group and 73.3% in the el-EVAR group (P = .30). CONCLUSIONS: Durable and sustainable midterm outcomes were found for both r-EVAR and el-EVAR patients who survived the postoperative period. Patients treated outside the IFU are at greater risk for late complications. Surveillance protocols may be tailored according to individual anatomy and IFU compliance rather than timing of repair.

Patients with large neck diameter have a higher risk of type IA endoleaks and aneurysm rupture after standard endovascular aneurysm repair.

OBJECTIVE: Standard endovascular aneurysm repair (EVAR) is the most common treatment of abdominal aortic aneurysms (AAAs). EVAR has been increasingly used in patients with hostile neck features. This study investigated the outcomes of EVAR in patients with neck diameters ≥30 mm in the prospectively maintained Endurant Stent Graft Natural Selection Global Postmarket Registry (ENGAGE). METHODS: This is a retrospective study comparing patients with neck diameters ≥30 mm with patients with neck diameters <30 mm. The primary end point was type IA endoleak (EL1A). Secondary end points included secondary interventions to correct EL1A, aneurysm rupture, and survival. RESULTS: This study included 1257 patients (mean age, 73.1 years; 89.4% male) observed for a median 4.0 years (interquartile range, 2.7-4.8 years). A total of 97 (7.7%) patients had infrarenal neck diameters ≥30 mm and were compared with the remaining 1160 (92.3%) with neck diameters <30 mm. At baseline, there were no differences between groups regarding demographics and comorbidities other than cardiac disease, which was more frequent in the ≥30-mm neck diameter group (P = .037). There were no significant differences between the groups regarding neck length, angulation, thrombus, or calcification. Mean preoperative AAA diameter was 64.6 ± 11.3 mm in the ≥30-mm neck diameter group and 60.0 ± 11.6 mm in the <30-mm neck diameter group (P < .001). Stent graft oversizing was significantly less in the ≥30-mm neck diameter group (12.2% ± 8.9% vs 22.1% ± 11.9%; P <. 001). Five patients (5.2%) in the ≥30-mm neck diameter group and 30 (2.6%) with neck diameters <30 mm developed EL1A, yielding a 4-year freedom from EL1A of 92.4% vs 96.6%, respectively (P = .09). Oversizing was 21.8% ± 13.0% for patients developing EL1A and 21.3% ± 12.4% for the remaining cohort (P = .99). In adjusting for neck length, AAA diameter, and device oversizing, patients with neck diameter ≥30 mm were at greater risk for development of EL1A (hazard ratio, 3.0; 95% confidence interval, 1.0-9.3; P = .05). Secondary interventions due to EL1A did not differ between groups (P = .36). AAA rupture occurred in three patients with neck diameter ≥30 mm (3.1%) and in eight patients with neck diameter <30 mm (0.7%; hazard ratio, 5.1; 95% confidence interval, 1.4-19.2; P = .016); two cases were EL1A related in each group. At 4 years, overall survival was 61.6% for the ≥30-mm neck diameter group and 75.2% for the <30-mm neck diameter group (P = .009), which remained significant on correcting for sex and AAA diameter (P = .016). CONCLUSIONS: In this study, patients with infrarenal neck diameter ≥30 mm had a threefold increased risk of EL1A and fivefold risk of aneurysm rupture after EVAR as well as worse overall survival. This may influence the choice of AAA repair and underlines the need for regular computed tomography-based imaging surveillance in this subset of patients. Furthermore, these results can serve as standards with which new, possibly improved technology, such as EndoAnchors (Medtronic, Santa Rosa, Calif), can be compared.

Anatomic predictors for late mortality after standard endovascular aneurysm repair.

OBJECTIVE: Abdominal aortic aneurysm (AAA) management involves a decision process that takes into account anatomic characteristics, surgical risks, patients' preferences, and expected survival. Whereas larger AAA diameter has been associated with increased mortality after both standard endovascular aneurysm repair (EVAR) and open repair, it is unclear whether survival after EVAR is influenced by other anatomic characteristics. The purpose of this study was to determine the importance of baseline anatomic features on survival after EVAR. METHODS: All patients treated at a tertiary teaching center with EVAR for intact standard infrarenal AAA from 2000 to 2014 were included. The civil data registry was queried to determine survival status; causes of death were obtained from death certificates. The primary study end point was to determine the impact of baseline morphologic features on all-cause and cardiovascular mortality after EVAR. RESULTS: This study included 404 EVAR patients (12.1% women; mean age, 73 years) with a median follow-up of 5.8 years (interquartile range, 3.1-7.4 years). The 5- and 10-year overall survival rates for the entire population after EVAR were 70% (95% confidence interval [CI], 66%-75%) and 43% (95% CI, 37%-50%), respectively. Only AAA diameter >70 mm (hazard ratio [HR], 1.75; 95% CI, 1.20-3.56) was identified as an independent anatomic predictor of all-cause mortality. Death due to cardiovascular causes occurred in 60 (38.5%) patients. Aneurysm-related mortality was responsible for six of the cardiovascular-related deaths. In multivariable analysis, both neck diameter ≥30 mm (HR, 2.16; 95% CI, 1.05-4.43) and AAA diameter >70 mm (HR, 2.45; 95% CI, 1.34-4.46) were identified as independent morphologic risk factors for cardiovascular mortality, whereas >25% circumferential neck thrombus (HR, 0.32; 95% CI, 0.13-0.77) was protective. CONCLUSIONS: This study suggests that patients with AAA diameters >70 mm are at increased risk of all-cause and cardiovascular mortality. In addition, patients with infrarenal neck diameters ≥30 mm have a greater risk of cardiovascular mortality, although AAA-related deaths were not more frequent in this group of patients. Consequently, a more aggressive management of cardiovascular medical comorbidities may be warranted to improve survival after standard EVAR in these patients.

Long-term outcomes of standard endovascular aneurysm repair in patients with severe neck angulation.

OBJECTIVE: Severe neck angulation is associated with complications after endovascular aneurysm repair (EVAR). Newer endografts may overcome this limitation, but the literature lacks long-term results. We studied the long-term outcomes of EVAR in patients with severe neck angulation. METHODS: A retrospective case-control study of a prospective multicenter database was performed. All measurements were made with dedicated software with center lumen line reconstruction. A study group including patients with neck length >15 mm, infrarenal angle (ß) >75 degrees or suprarenal angle (α) >60 degrees, and neck length 10 to 15 mm with ß >60 degrees or α >45 degrees was compared with a control group matched for demographics and other morphologic neck features. The primary end point was type IA endoleak (EL1A). Secondary end points were freedom from neck-related secondary interventions, primary clinical success, and overall survival. RESULTS: Forty-five patients were included in the angulated neck group and compared with 65 matched patients. Median follow-up was 7.4 years (interquartile range, 4.8-8.5 years). In the angulated neck group, mean α was 51.4 degrees (±21.1 degrees) and the mean ß was 80.8 degrees (±15.6 degrees); in the nonangulated group, these were 17.9 degrees (±17.0 degrees) and 35.4 degrees (±20.0 degrees), respectively. At 7 years, five patients in the angulated neck group and two nonangulated patients developed EL1A, yielding a freedom from EL1A of 86.1% (n = 14; standard error [SE], 0.069) and 96.6% (n = 34; SE, 0.023), respectively (P = .056). After exclusion of a patient who developed an EL1A secondary to an endograft infection, this difference was significant: 86.1% (n = 14; SE, 0.069) in the angulated neck group and 98.2% (n = 34; SE, 0.018) in the nonangulated group (P = .016). At 7 years, freedom from neck-related secondary interventions was 91.7% (n = 14; SE, 0.059) and 91.6% (n = 29; SE, 0.029), respectively. The 7-year primary clinical success estimates were 41.2% (n = 11; SE, 0.085) and 56.6% (n = 20; SE, 0.072) for the angulated neck and nonangulated groups, respectively (P = .12). The 7-year survival rates were 44.3% (n = 18; SE, 0.076) vs 66.7% (n = 42; SE, 0.059) for the angulated neck and nonangulated groups, respectively (P = .25). Device integrity failure was not observed. CONCLUSIONS: Despite satisfactory results early and in the midterm, a higher rate of EL1A was identified among patients with severely angulated necks in the long term. However, mortality was not affected by this difference. These findings suggest that EVAR should be used judiciously in patients with extreme angulation of the proximal neck and highlight the need for close follow-up of EVAR, especially in the long term and in patients treated outside instructions for use.