A 48-year-old woman with coarctation of the aorta, ventricular septal defect (VSD), and bicuspid aortic stenosis was followed with progressive aortic root dilation and severe aortic regurgitation. She also had moderate aortic valvular stenosis and underwent aortic valve and root replacement with a 22-mm homograft and reimplantation of the coronary arteries in 2002 at 38 years of age. This operation was complicated by right brachial artery occlusion requiring surgical bypass graft. She also developed third-degree heart block and underwent dual-chamber transvenous pacemaker placement. In the distant past, she had undergone initial repair of her coarctation and VSD closure at age 14 months in 1965 (coarctation resection with end-to-end anastomosis, required reoperation for residual coarctation in 1973 at 9 years of age). She had developed systemic hypertension and was managed with dual therapy using a beta-blocker and angiotensin-converting enzyme (ACE) inhibitor. She continued to have frequent headaches, fatigue with exertion, bilateral lower extremity pain, and fatigue with ambulation.
On physical examination, the patient had evidence of right brachial to left femoral pulse delay, the right femoral pulse was only faintly palpable. A 2/6 mid-systolic murmur was auscultated at the right upper sternal border. A soft systolic murmur was heard over the left scapula, no continuous murmurs or diastolic murmurs were appreciated. An S4 gallop was auscultated over the apex.
A stress echocardiogram in 2009 demonstrated a peak resting instantaneous gradient of 63 mm Hg, mean 32 mm Hg across the coarctation site, increased to PIG of 132 mm Hg with exercise. She had poor exercise capacity, went 6 minutes on a Bruce protocol with right upper extremity (RUE) blood pressure (BP) rising to greater than 200 mm Hg systolic, lower extremity exercise BP could not be measured. The decision was made to proceed with invasive catheterization to further assess anatomy and hemodynamics and to perform palliative intervention if deemed feasible and necessary.
The patient was brought to the catheterization laboratory and placed under general anesthesia in expectation of possible trans-catheter intervention. The right femoral pulse was faintly palpable, evaluation with ultrasound suggested an obstructed right femoral artery. The left femoral arterial pulse was palpated and a 6-French (F) sheath was placed under fluoroscopic and ultrasound guidance using the modified Seldinger technique.
Hemodynamic evaluation demonstrated a minimal gradient across the aortic homograft, an elevated left ventricular end-diastolic pressure (LVEDP) of 20 mm Hg, and a peak-to-peak gradient of 40 mm Hg across a focal area of re-coarctation in the proximal descending aorta (Figure 14-1).
Angiography demonstrated a focal narrowing at the site of prior coarctation repair, the transverse aorta, and descending aorta at the diaphragm measured 17 mm in diameter, the area of stenosis measured 8 mm in minimum diameter. A left femoral angiogram demonstrated complete occlusion of the left femoral artery by the 6-F arterial sheath (Figure 14-2). Intra-arterial nitroglycerin was given and the sheath was downsized to 4 F with manual pressure used to maintain hemostasis. Repeat angiography demonstrated an open but small caliber (<5 mm) common femoral artery. The decision was made to not proceed with percutaneous intervention via the femoral approach given the small-caliber left femoral artery (cannot abide the 12-F sheath needed for large-diameter stent placement).
The patient was taken off the table and bought back for a hybrid intervention with surgical exposure of the right subclavian artery. A 3-cm horizontal incision was made below the right clavicle and the artery was exposed (Figure 14-3). A micropuncture kit was used to access the artery and “preclosed” the artery with 2 Proglide sutures. A 10-F flexor sheath was positioned in the descending aorta. An EV-3 LD max 26 mm × 12-mm stent was mounted on a 14 mm × 3.5-cm BIB balloon and deployed, residual waist noted despite inflating to 8 atmosphere (atm) (Figure 14-4A). Angiogram performed post deployment, no evidence of dissection or aneurysm. The stent was postdilated with an Atlas PTA 14 mm × 2-cm balloon to a maximum pressure of 10 atm with minimal residual waist noted (Figure 14-4B).
Rotational angiography post deployment demonstrated a focal outpouching at the site of stent deployment, consistent with a controlled rupture of the aorta (Figure 14-5). Over 15 minutes, the pseudoaneurysm progressed from 1.5 mm in diameter to 3.5 mm in diameter. The decision was made to proceed with covered stent placement. A Melody valve was used as a “covered stent” by cutting out the valve leaflets (Figure 14-6A) and mounting the covered stent on an 18-mm BIB, placed through an 18-F sheath.
Angiography demonstrated a patent left subclavian artery, complete coverage of the pseudoaneurysm without residual “leak,” and a widely patent aorta at the prior coarctation site (Figure 14-6B). Simultaneous ascending and descending aorta pressure measurement did not demonstrate a residual gradient. The sheath was withdrawn and the Proglide sutures were tightened and cut. The incision was then surgically closed with running sutures (Figure 14-7).
The patient was discharged within 23 hours of the procedure. A chest computed tomography (CT) angiogram was performed 3 months following the operation and demonstrated excellent stent apposition, no evidence of endovascular leak, and a widely patent aorta (Figure 14-8). Her systemic blood pressure control improved appreciably and the ACE inhibitor was discontinued within 3 months of the procedure.
FIGURE 14-2
A. Complete occlusion of the left common femoral artery by a 6-F sheath. B. One hundred micrograms of intra-arterial nitroglycerine was infused and the 6-F sheath was exchanged for a 4-F sheath with subsequent improvement in distal flow. The common femoral artery measures 4.2 +/- 0.4 mm in minimal diameter and was deemed too narrow to accommodate a large-diameter long sheath necessary for coarctation angioplasty and stenting.
FIGURE 14-4
A. EV-3 LD max 26 × 12-mm large-diameter balloon expandable stent following deployment at a pressure of 8 atm on a 14 mm × 3.5-cm balloon. Note the residual waist at the area of residual coarctation. B. Redilation using a 14-mm Atlas balloon, inflated to 10 atm with resolution of residual stenosis.
FIGURE 14-8
A. 3D reconstruction, right posterior view of a chest CT angiogram 3 months postprocedure demonstrating excellent stent apposition, no evidence of endovascular leak, a widely patent aorta, and a patent left subclavian artery. B. Multiplanar reconstruction demonstrating minimal residual narrowing of the stented segment.
Transcatheter balloon angioplasty of aortic coarctation was first performed in 1982 and has been applied to discrete native coarctation and recurrent narrowing with considerable immediate success and a low rate of procedural complications.1 While the risk of death is low (<1%), the risk of dissection, aneurysm, or pseudoaneurysm formation is higher with angioplasty alone than with stenting.
While the immediate results of angioplasty are favorable, the intermediate and long-term results are less impressive, up to 50% of subjects require repeat intervention within a decade.2 Repeat interventions were for recurrent stenosis or aneurysm formation. The para-coarctation segments of the aorta harbor medial abnormalities that increase the risk of aneurysm and pseudoaneurysm formation (in up to 35% of patients) following angioplasty.3 Stent placement relieves obstruction and carries a lower risk of aneurysm formation.
Stent placement has become the treatment of choice for de novo and postsurgical residual coarctation in adults. The immediate, intermediate, and long-term outcomes of stent implantation are excellent. The resting gradient is virtually eliminated in most patients but most patients will continue to have an inducible gradient with exercise given the noncompliant nature of the stented segment.4
Procedural success (<20 mm Hg residual peak-to-peak gradient) occurs in 96% of cases, 4% of patients require repeat interventions and 1.3% may have aortic complications such as dissection or pseudoaneurysm formation.5 Other complications include stent fracture, access site complications, stent migration, balloon rupture, and arterial embolization. At long-term follow-up, 23% of patients continued to have systemic hypertension, 9% had an upper-to-lower limb blood pressure gradient in excess of 20 mm Hg, and 32% were taking antihypertensive medication.5
Covered stents can be used as a “bailout” in patients with dissection, aneurysm, or pseudoaneurysm formation. Internationally, the Cheatham-Palmaz stent from NuMed has become the stent of choice for most coarctations in adults. Currently, US Food and Drug Administration (FDA) approval of this device is pending in the United States.
