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We present the case of a 62-year-old woman who presented with recoarctation and then experienced rupture of the aorta and severe clinical deterioration after a stent was deployed. She was treated immediately by intrastent deployment of a stent-graft, which resolved the extremely serious situation.
Treatment of coarctation and recoarctation with a balloon catheter was first described in 1982 by Singer and colleagues.1 This procedure, however, was associated with a significant incidence of intimal lesions, dissections, and aneurysms.2 To improve the outcome, O'Laughlin and associates3 started using stent deployment in 1991, achieving good clinical results and reducing the incidence of complications.
In subsequent years, a number of articles proposed stent deployment without predilation as an alternative that could prevent, to a certain degree, migration of the stent.4–7 We report the successful treatment of an elderly patient who developed aortic rupture after Palmaz stent deployment and recoarctation.
In December 2005, a 62-year-old woman with a history of treated hypothyroidism, hypertension, and aortic coarctation was admitted to our hospital with effort angina of 1 year's progression and clinical data indicative of severe aortic valvular stenosis and recoarctation. At the age of 29 years, she had undergone resection and end-to-end anastomosis in treatment of the coarctation. At the present admission, Doppler echocardiographic study revealed the presence of a calcified bicuspid aortic valve with a maximum gradient of 100 mmHg, and a 60-mmHg gradient in the aortic isthmus.
We explained the nature of the therapeutic procedure and obtained the patient's informed consent. Cardiac catheterization via the femoral artery yielded normal coronary arteriographic findings. Aortography showed a calcified and stenotic bicuspid aortic valve, moderate dilatation of the aortic root, and severe narrowing in the isthmus due to recoarctation, with a 60-mmHg pressure gradient. Cardiac magnetic resonance imaging confirmed the findings (Fig. 1).
After discussing the case with the surgical team, we decided to deploy a stent in the recoarctation and to replace the valve in a 2nd operation. The procedure was performed by means of the right transfemoral catheter technique, with the patient under general anesthesia. Aortography in the 50° left anterior oblique projection disclosed a severe recoarctation segment 2 cm distal to the origin of the left subclavian artery (Fig. 2A); this measured 16 mm in the precoarctation segment, 18 mm in the postcoarctation segment, and 5 mm in the recoarctation site. An Amplatz extra-stiff 0.035-in, 300-cm guidewire (Boston Scientific Corporation; Natick, Mass) was introduced and looped just over the plane of the aortic valve. A 14F Mullins sheath (Cook Medical; Bloomington, Ind) was advanced over the wire and positioned in the distal aortic arch. Then a Palmaz 4014 XL stent (Johnson & Johnson Interventional; Miami, Fla) mounted on a BIB® dilatation catheter (inner balloon, 9 × 35 mm; outer balloon, 18 × 45 mm) (NuMED, Inc.; Hopkinton, NY) was advanced through the sheath to the recoarctation site. The Mullins sheath was withdrawn and the BIB balloon was inflated to a maximum pressure of 5 atm. Despite repeated inflations (Fig. 2B), the stent expanded only partially—which created a pronounced, persistent medial waist and the overall shape of a diabolo. At this point, we withdrew the BIB catheter and substituted a high-pressure 16 × 30-mm Mullins balloon (NuMED), which eliminated the stenotic waist at a pressure of 9 atm, thereby completing expansion of the stent (Fig. 2C).
Aortography performed immediately after deployment confirmed adequate apposition of the stent with the aortic wall but disclosed extravasation of contrast medium to the thorax as a fine jet, which, in angiographic images, spread to the posterior thorax (Fig. 2D). On the basis of recent reports of aortic rupture caused by stent deployment in the recoarctation segment,8–10 we already had prepared material to deal with this ominous complication, a measure that proved its worth.
Within minutes, the patient's systolic pressure fell to 50 mmHg, and severe bradycardia ensued. Anticoagulation was reversed with protamine, and blood was ordered urgently while plasma expanders were administered. Then the Mullins 14F sheath was rapidly removed and replaced with a 16F sheath (Cook), while the Amplatz guidewire was left in position. An 8-zig, 34-mm ePTFE Covered CP Stent™ (NuMED; not approved for this indication in the United States) was mounted on a high-pressure 18 × 40-mm Mullins balloon, which was advanced through the sheath and deployed intrastent at a pressure of 8 atm. This sealed the leak immediately, as confirmed by postoperative aortography (Figs. 2E–2G).
The clinical response was immediate, with stabilized blood pressure and heart rate. Blood transfusion was started and the patient was transferred to the intensive care unit, where a chest radiograph showed extensive opacification of the left hemithorax caused by a large acute hemothorax. A chest drainage tube was placed to enable complete evacuation.
The patient was discharged 7 days after the operation in good condition, with no obstruction at the stent on Doppler ultrasound study; she was directed to take aspirin as a platelet antiaggregant. Four months later, she underwent prosthetic replacement of the aortic valve, and 18 months after that, she remained asymptomatic.
Although good results have been reported with the deployment of stents for aortic coarctation and recoarctation, this technique is not without sequelae, such as aneurysm, pseudoaneurysm, and dissection of the aorta; migration, embolism, and incomplete expansion of the stent; and vascular complications associated with the femoral approach itself.2–5 The patient described here had the most life-threatening complication that can occur—aortic rupture—which was detected in its early stages, thanks to information from several recent papers,8–10 so it was dealt with promptly.
We are aware of 4 other cases involving aortic rupture subsequent to balloon angioplasty or stent deployment, 2 of which resulted in death of the patient.5,8–10 Our case is very similar to the one reported by Tan and Mullen10: it involved an adult with aortic recoarctation secondary to end-to-end anastomosis, with rupture caused by endovascular stenting, which was resolved by using a premounted stent-graft.
According to reports published about a decade ago,11,12 the formation of periaortic fibrous scarring subsequent to surgically repaired coarctation prevents, to a certain extent, the onset of aortic ruptures or fissures. Therefore, balloon angioplasty is considered to be a safe treatment option in cases of postsurgical recoarctation. However, aortic rupture has been reported occasionally, particularly after end-to-end anastomosis,8–10 which produces a rigid circumferential scar that cannot expand and eventually cracks, rupturing the wall. In adults, the likelihood of rupture is increased by calcification and by the use of oversized balloons and repeated inflations.
In our patient, the association between coarctation and the bicuspid valve should be considered not only as an obstructive focal process, but as genuine aortic disease, because it can cause structural changes in the aortic wall. Histopathologic findings in the wall of the aorta adjacent to the coarctation showed evidence of medial cystic necrosis. With aging, polysaccharide deposits can rupture the medial elastic fibers, an event followed by fibrosis and proliferation of collagen fibers, which further weakens the aorta and makes rupture more likely.8,13,14 To reduce the risks that are associated with vascular rupture, dissection, and aneurysm formation, Duke and colleagues15 suggested redilating previously implanted stents to obtain better results.
Sound advice was provided in an editorial comment by Hijazi,16 who underscored the following points: 1) The coarcted segment should be measured carefully with methods such as magnetic resonance imaging, in addition to angiography. 2) The diameter of the balloon must never exceed the diameter of the aortic isthmus or of the aorta at the level of the diaphragm. 3) Stent-grafting must be considered the treatment of choice and therefore be readily available at all laboratories where coarctation in adults is treated percutaneously. 4) If stent-grafting is unavailable, conventional stenting should be used as long as expansion does not exceed 3 times the diameter at the coarctation site, and as long as it never surpasses the diameter of the isthmus or the aorta at the level of the diaphragm.
In addition to these recommendations, Hijazi16 pointed out that when discrepancies are found between angiographic and MRI findings, intravascular ultrasound can be used to measure the aorta accurately at different locations to ensure the correct choice of balloon diameters. Intravascular ultrasound appears to be a promising and reliable means of guiding stent placement and expansion and of seeing changes in the diameter and structure of the vascular wall that may be early signs of complications.
Although it would have been possible to implant a self-expandable stent-graft in our patient as the treatment of choice after aortic rupture, our group has more experience with conventional balloon-expandable stents, which exert much greater radial stress in obstructive processes such as coarctation. In cases that involve aneurysmal formation after the deployment of stents in weakened aortic walls, self-expandable stents are safer, because the lower radial stress is less likely to cause rupture.17
We chose a hybrid sequential approach to manage the aortic recoarctation and valve disease in our patient, in order to diminish the morbidity and risk of death that are associated with 2 consecutive surgical procedures. Anumber of factors put our patient at risk of rupture: herage, recoarctation as the cause of the intrinsic alterations in her aortic wall, our use of a high-pressure balloon toachieve full expansion of the stent, and our inflation of that balloon to a diameter slightly larger than the isthmus. But an additional cause of rupture in our patient was the end-to-end anastomotic scar, which would not easily distend. Finally, intravascular ultrasonography was not available at our center at the time that this patient was treated, so we could not obtain more detailed information on the length and diameter of the coarctation site. Currently, in accordance with the recommendation of Hijazi,16 stent-grafting is, in our catheterization laboratory, the treatment of choice for endovascular stenting for all types of coarctation and recoarctation in adults.
In common with earlier reports, the case that we describe here confirms the importance of making stent-grafts available in the catheterization laboratory to cope with complications that have potentially fatal consequences, such as acute aortic rupture after stenting of recoarctation.
We thank K. Shashok for improving the use of English in the manuscript.
Address for reprints: Juan Alcibar, MD, PhD, Department of Hemodynamics, Hospital de Cruces, Pza. de Cruces s/n, 48903 Baracaldo, Vizcaya, Spain. E-mail: ten.aztedikaso.urch@rabiclaj