Case Report

In-Stent Restenosis and Aneurysm Development After Bare Stent Implantation: Rescue by e-PTFE-Covered Cheatham-Platinum Stent

Gianfranco Butera, MD, PhD, Davide Marini, MD*, Mario Carminati, MD

Gianfranco Butera, MD, PhD, Davide Marini, MD*, Mario Carminati, MD

ABSTRACT: We report on three cases of primary endovascular bare stenting for native aortic coarctation complicated by aortic aneurysm or in-stent stenosis because of neointimal proliferation that were successfully treated by covered stent. These cases show how the deployment of a covered stent may be a safe and definitive therapeutical option in the management of these complications.
J INVASIVE CARDIOL 2010;22:E209–E212
Key words: aortic coarctation, aortic aneurysm, covered stent endovascular stenting, congenital heart disease
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Aortic aneurysm development and intra-stent restenosis because of intimal build-up may complicate successful aortic coarctation endovascular stenting.1 We report on three cases in which a covered stent deployment was used as a rescue treatment to exclude aortic aneurysm or to relieve in-stent restenosis secondary to previous native coarctation bare stenting.

Case Reports

Patient #1. A 26-year-old female was referred to our Unit for percutaneous treatment of a native aortic coarctation. The cardiac magnetic resonance imaging (MRI) confirmed the presence of a subatretic isthmic coarctation (diameter, 2.7 mm) with pre- and post-stenotic aortic dilatation. At cardiac catheterization, the coarctation was treated by using a 39-mm long Genesis stent (Cordis, Miami, Florida) dilated up to 12 mm with a 50-mm long BIB balloon (NuMED, Hopkinton, New York) without any complications and achieving a satisfying anatomic and hemodynamic result (residual peak pressure gradient, 10 mmHg). Following the procedure, the hemodynamic gradient did not significantly change over 6 months of follow-up. However, at 12 months, echocardiography revealed progressive growth of the gradient across the isthmus with diastolic run-off on Doppler analysis. The patient underwent computed tomography angiography, revealing mild intra-stent restenosis because of neo-intimal proliferation with a marked persistent discrepancy between the stented isthmic aorta diameter and the proximal and distal descending aortic diameters. It was decided to perform a further interventional cardiac catheterization with serial dilation of the previous stent. The patient underwent general anesthesia and orotracheal intubation. Intravenous heparin (5,000 IU) was given after femoral artery cannulation achieved using an 8 French (Fr) introducer. The stenotic segment was crossed with a 6 Fr multipurpose catheter and exchanged for a 6 Fr pigtail catheter. The peak pressure gradient was measured between the 8 Fr femoral sheath and the 6 Fr pigtail in the ascending aorta at 24 mmHg. Anteroposterior, 40° left anterior oblique and lateral angiograms were obtained. The diameter of the stenotic area was 10 mm, while the diameter of the horizontal aorta at the level of the subclavian artery was 16 mm (Figure 1A). Redilatation was performed using a 15-mm crystal balloon (BALT, Montmorency, France) (Figure 1B). Unexpectedly, beyond the stenosis, aortic angiography revealed a discrete aortic aneurysm originating at the level of the proximal stent edge, with a maximum width of 4 mm (Figure 1C). In order to treat both the residual in-stent stenosis and the aneurysm, we decided to deploy a 34-mm, 8-zig Cheatham-Platinum (CP)-covered stent (NuMED) into the previous Genesis bare stent. A 15 x 50 mm BIB balloon was used to implant it. The stent was inflated by sequential manual inflation of inner and outer balloons until the covered stent was fully anchored within the previously deployed stent, covering and occluding the aortic aneurysm and sealing it without complication. Simultaneous pressure measurements showed no residual gradient across the aortic stented segment and final angiograms showed no evidence of residual stenosis nor aneurysm (Figures 1E and 1F). The patient was discharged the following day on aspirin. During follow-up, the patient underwent physical examinations, including blood pressure measurements, electrocardiograms and echocardiography at 1, 3, 6 and 12 months, and every 12 months thereafter. No residual pressure gradient appeared over a 5-year follow-up. Computed tomography angiography 6 months after the procedure showed no contrast filling of the aortic aneurysm and complete relief of the restenosis.
Patient #2. A 17-year-old boy was diagnosed with native subatretic aortic coarctation with dilatation of the aortic root. He underwent catheterization under general anesthesia in January 2002 (Figure 2A). An extremely severe coarctation (Patient #3.A 46-year-old female was referred to our department because of native aortic coarctation revealed by persistent and treatment refractory systemic arterial hypertension. The patient underwent cardiac catheterization under general anesthesia, which showed a complex native coarctation associated with diffuse hypoplasia of the descending aorta. The aortic hypoplasia and the isthmus measured 12 mm and 4 mm, respectively. The coarctation was successfully treated with a 48-mm XL AndraStent (Andramed GmbH, Germany) first dilated to 10 mm and then only in the proximal part with a 12-mm crystal balloon (BALT, Montmorency, France). Systolic arterial pressure decreased from 150 mmHg to 100 mmHg and the hemodynamic gradient fell from 53 mmHg to 6 mmHg. However, during follow-up, systemic arterial hypertension reappeared. The patient underwent a further cardiac catheterization 8 months later, which revealed a 40-mmHg peak-to-peak systolic gradient across the stent due to severe intrastent neointimal proliferation (Figure 3A). 45 mm, 8 zig and 34 mm, 8 zig covered CP stents were crimped onto a 10 mm BIB balloon and sequentially deployed. The first stent was expanded with its middle part aligned inside the proximal end of the previously placed AndraStent (Figure 3B), while the second stent was delivered with its middle part inside the distal edge (Figure 3C), with a short overlapping segment (Figure 3D). The residual pressure gradient was 2 mmHg and the final angiogram demonstrated no complications after the procedure (Figure 3E). At 3-month follow up, the blood pressure was normal and there was no residual Doppler abnormality at echocardiographic examination. Computed tomography angiography is scheduled at her 5-month follow-up exam. Discussion. Although the technical immediate success of stent implantation for aortic coarctation is established and relatively safe, data on the mid- and long-term safety and efficacy of percutaneous repair are just emerging.1–3 Neointimal hyperplasia, which is not clinically relevant in most patients, in rare cases may eliminate the successful hemodynamic effects of stent implantation.1 Aortic aneurysm is a known complication following both surgical and percutaneous treatment of native and recurrent coarctation.1,4 It is rare and mild in most cases, but may be the harbinger of aortic rupture, a potentially catastrophic dangerous complication of coarctation treatment. Both complications require reintervention and an optimal solution. We have already reported the successful use of the covered CP stent to treat recoarctation, native coarctation with aneurysm, and aortic aneurysm after balloon angioplasty or surgical repair.2,3,5 Here, we report on three patients in whom aortic aneurysms following previous coarctation stenting (Patients #1 and #2) and intrastent obstruction secondary to massive intrastent neointimal proliferation (Patient #3) were successfully treated using a covered CP stent in bare stent deployment technique. All procedures were performed without complications. In two of the patients, the follow-up was over 5 years. A recent multi-institutional study on intermediate outcomes of intravascular stenting for treatment of aortic coarctation using invasive or non-invasive techniques revealed that post-procedure aortic wall abnormalities (neointimal hyperplasia, aneurysms, dissections, intimal tear and stent fractures) are not infrequent.1 In this study, patients with abnormal findings at follow-up imaging had significantly small pre-stent and post-stent coarctation diameters. The risk of encountering dissections and aneurysms was related to the increase in coarctation diameter post-stent implantation, increasing balloon/coarctation ratio, and pre-stent angioplasty. Additionally, the development of in-stent restenosis was associated with a small post-stent diameter and post-stent systolic gradient.1 According to these data, both Patients #1 and #2 (who developed aortic aneurysm) had subatretic aortic coarctation with a balloon/coarctation ratio > 3,5 and Patient #3 (who developed intrastent stenosis) had a relatively small post-stent coarctation diameter and relatively large residual gradient. Of note, none of our patients underwent pre-stent balloon angioplasty, a recognized risk factor for aortic aneurysm.6 Patient #1 developed an aneurysm immediately after serial dilation of the Genesis stent. This occurred 18 months after successful bare stent deployment. Even if serial dilation of a covered CP stent has been recently described as a safe and effective technique, this may not be the case for serial dilation of a bare stent for coarctation.7,8 To our knowledge, there are no large published series focusing on this topic. In all of our cases, the use of the E-PTFE covered CP stent anchored into the bare stent resulted in a feasible and effective rescue technique for these aortic wall complications. Interestingly, the patients had three different bare stents implanted: Genesis, Palmaz and AndraStent. All these uncovered stents provided adequate support for the covered CP stent deployment. Only in Patient #3 were two covered CP stents necessary to cover the long segment of intrastent neointimal proliferation. Emergency stent graft deployment has also been successfully adopted for acute aortic rupture or after stent fracture following primary stenting for aortic coarctation.9 This supports our opinion that the covered stent is an important option in cases of aortic wall complications. Conclusion. We report on the successful deployment of an E-PTFE covered stent into a bare stent as a rescue procedure for aortic wall complications after coarctation stenting in three patients. This procedure is feasible, effective and safe at a mid-term follow up of 5 years. Life-long attentive follow up remains mandatory to rule out the late complications of endovascular leaks, aneurysm or restenosis.

References

1. Forbes TJ, Moore P, Pedra CA, et al. Intermediate follow-up following intravascular stenting for treatment of coarctation of the aorta. Catheter Cardiovasc Interv 2007;70:569–577. 2. Butera G, Piazza L, Chessa M, et al. Covered stents in patients with congenital heart defects. Catheter Cardiovasc Interv 2006;67:466–472. 3. Chessa M, Carrozza M, Butera G, et al. Results and mid-long-term follow-up of stent implantation for native and recurrent coarctation of the aorta. Eur Heart J 2005;26:2728–2732. 4. von Kodolitsch Y, Aydin MA, Koschyk DH, et al. Predictors of aneurysmal formation after surgical correction of aortic coarctation. J Am Coll Cardiol 2002;39:617–624. 5. Butera G, Piazza L, Chessa M, et al. Covered stents in patients with complex aortic coarctations. Am Heart J 2007;154:795–800. 6. Forbes TJ, Garekar S, Amin Z, et al. Procedural results and acute complications in stenting native and recurrent coarctation of the aorta in patients over 4 years of age: A multi-institutional study. Catheter Cardiovasc Interv 2007;70:276–285. 7. Butera G, Gaio G, Carminati M. Redilation of e-PTFE covered CP stents. Catheter Cardiovasc Interv 2008;72:273-–277. 8. Bruckheimer E, Dagan T, Amir G, Birk E. Covered Cheatham-platinum stents for serial dilation of severe native aortic coarctation. Catheter Cardiovasc Interv 2009;74:117–123. 9. Tan JL, Mullen M. Emergency stent graft deployment for acute aortic rupture following primary stenting for aortic coarctation. Catheter Cardiovasc Interv 2005;65:306–309.
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From the Pediatric Cardiology and GUCH unit, Policlinico San Donato, IRCCS, Italy and *Pediatric Cardiology, OIRM Sant’Anna, Torino, Italy. The authors report no conflicts of interest regarding the content herein. Manuscript submitted February 19, 2010, provisional acceptance given March 29, 2010, final version accepted April 12, 2010. Address for correspondence: Dr. Gianfranco Butera, Pediatric Cardiology, Policlinico San Donato IRCCS, Via Morandi, 30, 20097 San Donato Milanese, Italy. E-mail: gianfra.but@lycos.com