Abstract
Background:
In the abdominal aorta, the use of knitted rather than woven dacron prostheses has shown an early and slow late dilation. The dilation of woven versus knitted dacron prostheses in the thoracic aortic position has not yet been investigated.
Method:
From 1992, 25 patients entered a prospective study: 13 Gelweave® and 12 Gelseal® prostheses (diameter 18–26 mm) were implanted in the descending thoracic aorta. Computed tomography (CT) scans without contrast-enhancement were performed 2 weeks, and 1 and 2 years postoperatively. The full length of the grafts was scanned and the diameter was measured in mm measured at a level outside the areas of intercostal artery reimplantation. Patient determinants analysed were age, hypertension and implantation diameter of the grafts. The Gelseal group had a mean age of 63.7 years and seven were males. The Gelweave group had a mean age of 67.8 years and seven were males.
Results:
The mean implantation diameters were 19.6 ± 1.7 mm and 22.0 ± 2.7 mm (P = 0.02) for the Gelseal and Gelweave grafts, respectively. On the CT-scans at 2 weeks postoperatively, the diameter had increased by 18.8 ± 4.8% (P = 0.0001) in the Gelseal and by 5.7 ± 6.4% (P = 0.007) in the Gelweave grafts. This difference in diameter at 2 weeks between the two prostheses was significant (P < 0.00001). At 1 year the diameter had increased by 28.4 ± 5.2% (P = 0.0001) and by 8.4 ± 4.6% (P = 0.0003) for the Gelseal and Gelweave grafts, respectively, compared with the implantation diameter. The increase in diameter between the postoperative values at 2 weeks and those at 1 year was statistically significant in the Gelseal grafts (P = 0.0002) but not in the Gelweave grafts (P = 0.56). At 2 years an increase in diameter by 31.4 ± 5.2% (P = 0.0001) and by 7.4 ± 7.1% (P = 0.014) for the knitted and woven prosthetic grafts, respectively, was noted compared with the initial implantation diameter. The increase in diameter between the CT measurements at 2 weeks and those at 2 years was statistically significant in the Gelseal group (P = 0.001) but not in the Gelweave group (P = 0.86). The difference in this late increase in diameter between the two implanted grafts was also significant (P < 0.005). Age, hypertension and initial diameter did not appear to be significant determinants.
Conclusion:
In contrast to the Gelseal prosthesis in the descending aorta, the Gelweave prosthesis does not show any late dilation.