ALTURA™ Stent Graft Shortening and Its Implications After EVAR

Abstract

Objectives: The ALTURA™ stent graft system is designed for the treatment of abdominal aortic and/or aorto-iliac aneurysms. This study evaluates the performance of the ALTURA™ stent graft, focusing on AAA diameter, landing zones, stent graft length, and migration following endovascular aortic repair (EVAR). Methods: This is a retrospective analysis of computed tomography (CT) images focuses on patients with infrarenal abdominal aortic aneurysm (AAA) treated with the ALTURA™ stent graft system (Lombard, Ltd., Didcot, UK) at Pauls Stradins Clinical University Hospital in Riga, Latvia, and University Hospital Düsseldorf in Düsseldorf, Germany. The study population consisted of patients with asymptomatic AAAs who underwent elective treatment between January 2014 and June 2017. Follow-up CT scans were performed at one month, six months, one, two, and three years after implantation. Changes in stent graft length, aneurysm sac diameter, and the proximal and distal sealing zones were evaluated. Results: A retrospective analysis was conducted on computed tomography (CT) images from 40 patients (mean age 70.4 ± 8.5 years, 34 males, 6 females) who were treated with the ALTURA™ stent graft system for infrarenal abdominal aortic aneurysms (mean aneurysm diameter 5.6 ± 1.0 cm). The mean follow-up duration was 24.2 ± 10.6 months, with CT scans completed for all patients at one month and for 80% at one year. The mean total shortening of the stent graft one year after EVAR was 4 ± 3 mm (p < 0.001), 7 ± 5 mm after two years (p < 0.001), and 9 ± 6 mm after three years (p < 0.001). The iliac extensions shortened by 4 ± 3 mm after one year (p < 0.001), 6 ± 4 mm after two years (p < 0.001), and 8 ± 4 mm after three years (p < 0.001). Significant shortening was observed in the iliac extension, while changes in the aortic stent graft were not statistically significant. The reduction in the distal sealing zone and upward migration of the stent graft were 3 ± 3 mm after one year (p < 0.001), 5 ± 5 mm after two years (p < 0.001), and 7 ± 7 mm after three years (p < 0.001). Over the follow-up period, significant stent graft shortening and loss of the distal sealing zone were observed. However, these changes remained within a clinically acceptable range and did not lead to type I endoleak. Aneurysm sac shrinkage greater than 10 mm one year after treatment was observed in 25% of patients (p < 0.001). No aneurysm ruptures or AAA-related deaths were reported. Conclusions: Significant shortening of ALTURA™ stent graft, migration, and sealing zone reduction were observed without clinical impact after three years. However, in patients with short distal sealing zones, these changes could increase the risk of type Ib endoleak. Longer follow-up is needed to assess long-term durability.

Keywords: ALTURA™ stent graft system; aneurysm sack shrinkage; endoleak; endovascular aortic repair; stent graft migration; stent graft shortening.

Figure 1

The ALTURA™ stent graft system is uniquely designed with two bilateral ‘D’-shaped proximal aortic stent grafts, complemented by iliac extensions.

Figure 2

Abdominal aortic aneurysm showing the instructions for use for the ALTURA™ stent graft system.

Figure 3

Proximal sealing zone. A—distance from renal artery to renal radiopaque marker, B—renal artery radiopaque marker, C—renal artery. The red line is the central line of the stent graft and artery.

Figure 4

Distal sealing zone. A—distance from end of the stent graft to external iliac artery, B—internal iliac artery. The red line is the central line of the stent graft and artery.

Figure 5

ALTURA™ stent graft parts and segments. A—proximal part of aortic stent graft, B—overlapping zone of aortic stent graft and iliac extension, A and B—aortic stent graft, C—distal part of iliac extension, B and C—iliac extension, D—renal artery, E—renal artery radiopaque marker, F—total length of stent graft. The red line is the central line of the stent graft and artery.

Figure 6

Changes of maximal aneurysm sac cross sectional area over time. (A)—before treatment 27.1 cm², (B)—1st month follow-up 27.7 cm², (C)—6th month follow-up 22.1 cm², (D)—1st year follow-up 15.9 cm², (E)—2nd year follow-up 12.4 cm², (F)—3rd year follow-up 10.7 cm².

Figure 7

Shortening of Altura stent graft. (A)—1st month follow-up with stent graft length 17.3 cm, (B)—1st year—16.6 cm, (C)—2nd year—15.9 cm (D)—3rd year—15.7 cm, a—aortic stent graft renal artery radiopaque marker, b—end of the iliac stent graft.

Figure 8

Stent graft upward migration in iliac arteries and reduction of distal sealing zone in patient with aneurysmatic common iliac artery. (A)—1st month follow-up, (B)—1st year with stent graft upward migration 0.5 cm, (C)—2nd year—1.0 cm, (D)—3rd year—2.5 cm, a—end of the iliac stent graft, b—external iliac artery. The green line is a central line of stent graft and artery.

Figure 9

Stent graft downward movement in infrarenal aortic neck and reduction of proximal sealing zone. (A)—1st month follow-up, (B)—1st year with stent graft downward movement 4 mm, (C)—2nd year 5 mm, (D)—3rd year 6 mm, a—lowermost renal artery, b—aortic stent graft renal artery radiopaque marker. The green line is a central line of stent graft and artery.