Self- and balloon-expandable stent implantation for severe native coarctation of aorta in adults.

BACKGROUND: Balloon angioplasty for native coarctation of the aorta (CoA) in adults, though promising, is sometimes limited by significant residual gradient (>20 mm Hg). Few studies available have reported on use of balloon-expandable stents in such a situation. We evaluated the use of self- and balloon-expandable stents in patients with suboptimal response to balloon angioplasty (BA).
METHODS: Twenty-one hypertensive patients (age, 18 to 61 years; mean, 28.6 +/- 11.2 years) with native CoA and in whom results of BA were suboptimal (ie, residual peak systolic gradient [PSG] >20 mm Hg) underwent stent implantation. Balloon-expandable Palmaz stents were implanted in 5 patients (group A) and self-expandable nitinol aortic stents in the remaining 16 patients (group B).
RESULTS: In group A, PSG decreased from 62.8 +/- 10.6 (53 to 80) mm Hg to 28.1 +/- 6.3 (22 to 39) mm Hg after BA. Systolic gradient further decreased to 8.3 +/- 3.9 (2 to 16) mm Hg (P <.001) after implantation of the balloon-expandable Palmaz stent. In group B, PSG decreased from 70.2 +/- 24.6 (40 to 110) mm Hg to 28.4 +/- 9.8 (22 to 42) mm Hg after BA and further reduced to 9.0 +/- 5.5 (4 to 16) mm Hg (P <.001). One of these patients had a nitinol self-expandable stent implanted after a Palmaz stent embolized immediately after deployment. Nitinol stents were easier to deploy and conformed better to aortic anatomy compared with balloon-expandable stents. In group A, the diameter of the coarcted segment increased from 3.8 +/- 0.8 mm to 13.3 +/- 0.8 mm (P <.001) after stent implantation and in group B it increased from 4.5 +/- 1.1 mm to 14.1 +/- 2.1 mm (P <.001). There was no significant difference between the two groups in the PSG and diameter of the coarcted segment before and after stent implantation. With the exception of one case, in which a Palmaz stent embolized, there was no other complication in our series. On follow-up of 12 to 71 months (mean, 40.7 +/- 5.8 months) all the implanted stents remained in their original position and none showed evidence of fracture. Improvement in hypertension was seen in 20 of 21(95.2%) of the patients. On recatheterization and angiography 1.2 +/- 0.6 years after implantation in 19 patients, one patient showed an increase in PSG to 27 mm Hg across the nitinol stent and underwent successful redilation. No increase in gradient was seen in other patients. Beneficial late remodeling was seen in 10 of 14(71.4%) of patients restudied after implantation of self-expandable stent. None of the patients showed aneurysm formation.
CONCLUSIONS: Stent implantation is safe and effective in improving suboptimal results after BA for CoA. Self-expandable stents were easier to implant, adapted better to the wall of the aorta, and in most patients had similar efficacy in reducing coarctation as balloon-expandable stents.