Valvar pulmonary stenosis (PS) is far less common in the adult population than in children and young adults, but when left untreated into adulthood, it can cause significant symptoms. Unlike the aortic valve, the pulmonary valve does not
generally calcify and is thus typically amenable to balloon dilatation. The long-term follow-up of repaired valvar PS, by surgical or balloon valvuloplasty, demonstrates that in most cases it is a highly successful, if not curative, procedure.¹ Late valvar insufficiency may also cause symptoms of shortness of breath, or fatigue, on exertion, but is more frequently a product of surgical intervention.²

Severe infundibular stenosis after valvuloplasty, which has been termed the “suicide” right ventricle³ in surgical series, is physiologically identical to left ventricular outflow tract obstruction in hypertrophic cardiomyopathy; hypovolemia and increased inotropic states augment the degree of obstruction, which is typically a product of long-standing PS with RV hypertrophy. The cyanosis in this patient was driven by long-standing RV hypertrophy and reduced RV diastolic compliance sufficient to elevate RA pressures and resistance to filling, contributing to preferential right-to-left shunt across the patent foramen ovale.

In children, in whom most PS repairs are performed, standard valvuloplasty balloons are very effective, and also inexpensive. In adults and in teenagers, the size of the valve annulus is such that a double-balloon technique is often required to obtain enough dilating force and diameter. The Inoue balloon (see earlier discussion) can be selected to suit larger diameters and is variable in its inflation size, so that a larger inflation size can be used without needing to change the catheter.⁴

Balloon valvuloplasty is a highly effective and extremely safe catheter intervention. It should be considered the procedure of choice for valvar PS.

De novo diagnosis of coarctation in the adult population is uncommon, but patients who have had previous aortic coarctation surgery may have residual obstruction at surgical sites. Any patient with systemic arterial hypertension should have examination of the lower extremity pulses, and the four extremity pressures should be checked at least once during their lifetime to rule out this disease. In children who have not reached full adult size, surgery was historically the preferred therapy for native coarctation, although increasingly, centers with appropriate expertise offer primary balloon angioplasty when it is both anatomically and physiologically suitable. For recurrent coarctation after surgical repair in children, however, balloon angioplasty is accepted as the procedure of choice, when feasible. Stenting is generally not used in younger children given their growth potential, but has become widely accepted in older children, as well as in adults with coarctation.⁵,⁶ Stenting appears to provide more control in dilating the coarcted segment and eliminates the need for oversizing of the balloon with attendant risks of aortic rupture, tear, or dissection.

Many centers are increasingly performing “predilation” (balloon expansion at the site intended to ultimately receive a stent) in a staged fashion and with limitations in permitted waist-balloon diameter ratio, so as to assess compliance of the aortic wall and to presumably decrease
the risk of both underdilation and vessel rupture. In this patient’s case, predilation was not chosen by the intervention center—though dilation was performed in a staged approach—owing to the small size of the native vessel. The initial stent size was limited to 4 to 5 times the initial diameter of the coarctation lesion; the patient returned after 6 months (with presumptive healing of the stent site) for fuller stent expansion.

Stent placement is also possible in more proximal lesions, such as coarctation that involves the transverse arch and isthmus, and may impinge on the left subclavian or even the carotid vessels. Lesions in each of these locations have been successfully treated with stent angioplasty without adverse neurologic events or arm ischemia.⁷ Some congenital interventional cardiologists have endorsed the use of covered stents to reduce the risk of acute aortic injury. These stents have been utilized as “rescue” treatment in patients with periprocedural dissection, rupture, or aneurysm formation, and have been suggested for use (a) for postprocedural (surgery or percutaneous) aneurysms located at or near the coarctation site, (b) in patients in need of repair with native or repaired coarctation, who have particular risk of procedural complication (e.g., anatomy with atretic/near atretic coarctation, tortuosity, and long segmental involvement), and (c) for stent failure (stent fracture or in-stent restenosis). Anecdotal data support use of covered stents under specific local and FDA protocol for periprocedural dissection or rupture. For any other indication, it should be noted that covered stents do not have FDA approval for treatment of aortic coarctation in the United States. They have been utilized as implantation therapy mainly in Europe, but very scarce data are available on the longer-term follow-up in patients who have undergone
this treatment. The ongoing Coarctation of the Aorta Stent Trial (COAST) is a nonrandomized, multicenter, open-label study addressing the safety and efficacy profile of covered Cheatham Platinum stent use in children, adolescents, and adults with coarctation of the aorta and estimated or measured transcoarctation pressure gradient of at least 20 mmHg. This study will be useful to better define the clinical indications and efficacy of this type of stent in percutaneous treatment of coarctation of the aorta.