How should we treat coarctation of the aorta?

Coarctation is a narrowing of the aorta located between the first brachiocephalic vessel and the aortic bifurcation. When isolated coarctation is associated with congestive heart failure, it is considered clinically important,2 but what is "important" when the child is asymptomatic? Shaddy et all use as an entrance criterion "hemodynamically significant native coarctation of the aorta" without giving parameters for "significant." Is it an elevated right arm blood pressure at rest? A resting arm-leg gradient of 20 mm Hg,3,4 or 30 mm Hg5? Is it an exercise-induced gradient of 52 mm Hg without gradient at rest6? Not considered in the study by Shaddy et al, exercise effect in coarctation further complicates the issue because of limited data,7-9 especially simultaneous arm-to-leg measurements.10'1' Surgical repair has been standard therapy for coarctation since 1945.12 Many now recommend balloon dilatation for previously operated coarctation3'4"13"14; some extend this preference to the unoperated or "native" coarctation.5"15"16 Shaddy and colleagues performed a randomized, prospective study on 36 children with unoperated isolated coarctation (ages 3-10 years), comparing surgery (resection and end-to-end anastomosis in 13 of 16) with balloon dilatation (20 patients). There were no deaths. By the authors' assessment, complication rates and types were considered similar (to be discussed later). Residual stenosis was present in 25% of patients after balloon dilatation and 6% after surgery. Shaddy et all found a higher incidence of pressure gradient after balloon dilatation than has been reported by other centers after either surgery'0'11"7 or balloon dilatation.5"8"9 Residual obstruction can result from stenosis incompletely resolved by the procedure and/or stenosis not addressed by the procedure, usually proximal hypoplasia of the transverse aortic arch.