Intraluminal ultrasound imaging through a balloon dilation catheter in an animal model of coarctation of the aorta

Anatomy of coarctation, hypoplastic and interrupted aortic arch: relevance to interventional/surgical treatment

Obstructive lesions in the aortic arch are comprised of discrete coarctation, tubular hypoplasia and interruption. This review discusses the anatomy of the lesions relevant to interventional treatment. Catheter intervention, using not only balloon angioplasty but also stent implantation for coarctation, has been developed over the past couple of decades as an alternative treatment to surgery. Several studies have reported long-term outcome and the benefits of surgery and catheter intervention for treating obstructive lesions in the aortic arch but more studies are needed for comparable evaluations. The development of imaging and further improvement of surgical and catheter intervention, such as hybrid intervention or new devices, will help in removing the obstruction safely.

Middle aortic syndrome treated by stent implantation

OBJECTIVES

To determine outcome of stent implantation in patients with middle aortic syndrome.

DESIGN

Prospective study, case series.

SETTING

A tertiary paediatric cardiology centre in a children's hospital.

PATIENTS

Five patients, aged 4 to 17 years (mean 11.4 years), with upper limb hypertension due to middle aortic syndrome.

INTERVENTION

Stents were implanted in the mid/lower thoracic/upper abdominal aorta.

MAIN OUTCOME MEASURE

Satisfactory deployment of stents and blood pressure control.

RESULTS

In all patients, angiocardiography showed long segment stenosis in the mid or lower thoracic/upper abdominal aorta. The pressure gradient was between 40 and 90 mm Hg (mean 63.2 mm Hg). Seven Palmaz stents were implanted. Immediately after implantation, the gradient decreased to between 0 and 35 mm Hg (mean 13.6 mm Hg). Angiography showed a satisfactory result with widely patent stents in all. In one patient, thrombosis of the stent occurred six days after implantation. This was successfully treated with infusion of alteplase, further balloon dilatation, and implantation of a second stent overlapping the first, both dilated to 10 mm diameter. One patient had elective redilatation of the stent six months after implantation, with further reduction of the gradient from 35 mm Hg to 10 mm Hg. At the latest follow up between three and 20 months (mean 12.2 months) after stent implantation, in four patients blood pressure was better controlled with antihypertensive drugs. One patient was normotensive without drugs. Computed tomography showed no aneurysm formation in the region of the stents.

CONCLUSIONS

Stent implantation is a preferable alternative to surgery in the treatment of patients with middle aortic syndrome and merits further evaluation.

Mechanism of balloon angioplasty in children with arterial stenosis assessed by intravascular ultrasound and angiography

Fifteen patients were examined before and immediately after balloon angioplasty with a 4.3F, 30 MHz rotational tip intravascular ultrasound system. In 12 (80%) patients, 13 procedures could be analyzed because of sufficient image quality. The lesions for intravascular ultrasound (IVUS) study consisted of pulmonary arterial stenosis in 4 patients, Blalock-Taussig shunt stenosis in 3, coarctation of the aorta in 2, subclavian artery stenosis in 1, renal artery stenosis in 1, and ductus arteriosus in 1. Three distinctive morphologic types were identified: Group I had arterial stretching (3 patients); group IIa had superficial tearing (3); group IIb had deep intimal-medial tearing (5); group III had dissection (2). In the narrowest site, minimal and maximal luminal diameters, luminal area before and after balloon angioplasty were 3.5 +/- 1.8 mm vs 4.5 +/- 2.5 mm, 4.1 +/- 2.1 mm vs 5.4 +/- 3.5 mm, and 49.8 +/- 30.2 mm vs 88.3 +/- 45.2 mm2, respectively. The recoil value of group IIb with appropriate balloon angioplasty was approximately 0.3. IVUS may be an useful modality for evaluating the morphologic mechanism of dilatation after balloon angioplasty.