Exercise testing is useful to screen for residual coarctation in children

Twenty-seven children (ages 8 to 18 years) who had a history of successful coarctation repair (mean transisthmic Doppler gradient [TI-D] <20 mmHg at rest) and had not received antihypertensive medications underwent echocardiogram at rest and immediately following peak exercise with a standard treadmill test. All were normotensive or had isolated systolic hypertension at rest. Right arm-ankle (RA-A) systolic blood pressure (SBP) difference and TI-D were measured. Eleven children (41%) demonstrated exercise-induced hypertension (peak exercise SBP >98th percentile per body surface area) and 17 (63%) had a mean TI-D > or =40 mmHg. Eight underwent MRI or angiography; a residual coarctation (RCoA) was confirmed in three and excluded in five. RCoA was excluded in three other children who were normotensive at rest and had normal postoperative echocardiographic findings. No individual test (SBP, RA-A SBP, TI-D) at rest or with exercise testing was statistically useful to identify RCoA. However, the requirement for a RA-A SBP difference > or =20 mmHg and a TI-D > or =40 mmHg during exercise testing was a useful screen: RCoA was present in three of five children who fit these criteria but was absent in six of six who did not.