Coarctation of the aorta in the adult: Medical management and evaluation

Associate Professor of Medicine, McGill University,
Director, MAUDE Unit (McGill Adult Unit for Congenital Heart Disease),
McGill University Health Center, Canada
Ariane Marelli

Prevalence and Anatomy: Aortic coarctation is a common congenital lesion in the infant population in whom the presentation can be that of a severe low output state. In adolescence and adults, the diagnosis should always be sought in the event of unexplained hypertension of the upper extremities. The anatomy of coarctation, typically consists of a constriction just distal to the left subclavian at the site of the aortic ductal attachment or its residual ligamentum arteriosum. Less commonly the coarctation ridge lies proximal to the left subclavian, giving rise to a differential blood pressure in the upper extremities. When aortic coarctation is diagnosed, careful assessment of the mitral inflow and the aortic outflow in its entirety is necessary for assessment of associated lesions. A bicuspid aortic valve is the most common coexisting anomaly, but obstruction above or below the valve as well as malformations of the mitral-valve apparatus should not be missed. The coexistence of a VSD or a patent ductus arteriosus is well documented. The transverse arch should be carefully examined for tubular hypoplasia.“Pseudocoarctation” refers to buckling or kinking of the aortic arch without presence of a significant gradient.
Outcome: Complications of aortic coarctation include secondary left-ventricular hypertrophy, systemic hypertension, heart failure, aortic dissection, premature coronary disease, and cerebrovascular complications. With untreated coarctation a mean survival of 35 years with a 75% mortality by age 50 years can be expected.
In a long-term study from the Mayo clinic, of over 500 patients who underwent coarctation repair, estimated survival at 30 years was 76％. Outcome after repair is closely related to the age at operation, with long-term survivorship maximized when surgery is performed prior to age 10. Fifty percent of patients repaired after age 40 have residual hypertension, while those having undergone surgery between the ages of 1 and 5 have a less than 10％ prevalence of hypertension on long-term follow-up. Not surprisingly, for those who have required surgery before the age of 1, the incidence of residual systemic hypertension is higher, reflecting the severity of neonatal coarctation syndrome. Even in the absence of systolic hypertension at rest after successful coarctectomy, an abnormal hypertensive response to exercise and a persistently elevated left-ventricular mass have been documented. Cerebral vascular complications, myocardial infarction, and aortic dissection can occur in 2 to 6％ of patients. After the age of 40, heart failure becomes increasingly frequent in the presence of unoperated coarctation and may persist after coarctation repair.
Management: Intervention in patients with coarctation or recoarctation, should be performed with gradients greater than 50 mm Hg documented by cardiac catheterization. For patients with gradients above 20mmHg, the occurrence of symptoms and/or systemic hypertension warrants consideration for intervention.
Aortic coarctation can safely and effectively be treated with balloon dilatationwith or without stent implantation particularly for adult patients with re-coarctation following surgical repair. Incomplete relief is observed in 25% of patients with recoarctation vs 19% of patients with native coarctation. Restenosis remains a concern and appears to occur more frequently in children with native coarctation. The incidence of incomplete relief and restenosis is decreased in adolescents and adults with endovascular stent implantation. Aortic aneurysm formation is reported 7-17% of adult patients and aortic rupture occurs rarely. Percutaneous coarctoplasty is contraindicated in those with transverse arch hypoplasia. Percutaneous coarctoplasty is being increasingly used as an alternative to surgical intervention. It is the treatment of choice for focal recoarctation in adult patients who are previously operated. For adults with native coarctation, the choice of surgery or percutaneous coarctoplasty depends the coarctation anatomy, the presence or absence of associated anomalies as well as on local expertise.
Surgical intervention is well established. Complications include paraplegia due to spinal cord injury, and late complications as described above. Surgery is more hazardous in adults than in children. When patients of all ages are considered, peri-operative death rates are 3% or less. The incidence of paraplegia is less than 1%. The preferred surgical approach is resection with end-to-end anastomosis of the descending aorta. This approach has the advantage of removing the site of cystic medial necrosis, which has been observed at the site of coarctation, thereby decreasing susceptibility to aneurysm formation and dissection. Recoarctation is least common when an end-to-end anastomosis is performed, but the prevalence varies from 11% requiring a re-operation to as high as 30%, depending on the age of repair and the surgical approach used. Latent development of coronary artery disease and systemic hypertension require lifelong monitoring.