Coarctation of the aorta in adults: do we need surgeons?

Coarctation of the aorta is a common congenital defect, which although normally detected and surgically repaired in childhood may present in adolescence or adulthood, usually in the context of investigation for hypertension. The morphological spectrum of abnormalities range from a discrete stenosis distal to the left subclavian, often with extensive collateral formation, to a hypoplastic transverse arch and aortic isthmus, that typically presents in infancy. In some patients coarctation is caused by a long tubular stenosis of the descending thoracic aorta. The natural history of untreated coarctation is that of premature death from stroke and coronary heart disease or sudden death and relief of anything but the mildest of obstructions is usually indicated. The techniques for surgical repair of aortic coarctation have progressively evolved over the past 50 years. In the largest series to date, representing 646 operations performed between 1946 and 1981, perioperative mortality was highest in infants, lowest in children aged 1–14 years, before gradually increasing in the adolescent and adult population to a peak of 4.5% in adults > 30 years old. While undoubtedly, improvements in technique have significantly reduced operative risk in younger children, few data are available on morbidity and mortality in adult populations and the technical difficulties which underlie the increased risk will remain. 6 The most devastating complication of coarctation surgery is paraplegia, related to long cross clamp times and injury to spinal arteries, which occurs in approximately 0.5–1% of cases. Other complications include paradoxical hypertension, postcoarctectomy syndrome related to reperfusion of viscera, injury to the phrenic or recurrent laryngeal nerve, and pleural effusion or complications of thoracotomy. Recoarctation and aneurysm formation, although relatively rare in the current surgical era, are important late complications. Against this backdrop the development of interventional techniques inevitably led to attempts at transcatheter relief of coarctation. Balloon angioplasty has been used for over 20 years. It is an inherently traumatic treatment and effects an increase in vessel diameter through disruption of the aortic intima and media. As a result its use in native coarctation, where the artery is already intrinsically weakened by cystic medial necrosis, remains controversial. A degree of recoil is inevitable following balloon dilatation and the obstruction may not be adequately relieved, resulting in a high rate of reintervention, particularly in non-discrete coarctation. In early studies this may have led to overdilatation, explaining the high incidence of aneurysm formation reported to occur in between 5–20% of cases following balloon angioplasty and occasional catastrophic and fatal disruption of the aorta. Despite this, results comparable with that achieved at surgery have been reported. 10 More recently, with improvements in technology, endovascular stents have been used to treat coarctation. Unlike balloon dilatation, stents utilise the elastic properties of the aortic wall to affect an increase in luminal diameter, which would otherwise recoil. While in children their use is limited by the size of current delivery systems and the intrinsic need for redilatation in line with somatic growth, in older children and adults stents represent a viable alternative to surgery.