312 Exercise testing coupled with Doppler echocardiography: a simple, safe and effective method to assess the severity of coarctation of the aorta

Abstract

Peak systolic Doppler velocity at the aortic isthmus alone is not a good predictor of severity in patients with native or residual coarctation (CoA). A major argument in favour of a hemodynamically significant CoA is the presence of a diastolic gradient (DG) with characteristic “sawtooth” appearance of the Doppler pattern. to evaluate, in patients with some degree of aortic isthmus narrowing but without significant DG at rest, if exercise could unmask DG and thus hemodynamically significant CoA. Fourteen patients aged from 12 to 56 years underwent treadmill exercise testing coupled with Doppler echocardiography. Thirteen had previous CoA repair 8 to 43 years before, one had aortic kinking with mild isthmic narrowing on CT-scan. MRI or CT-scan were performed in 11 patients, showing significant residual stenosis (narrowing > 30%) in 8/11. Doppler measurements were performed during exercise testing and 5 minutes after at the suprasternal notch, using a CW-Doppler 2 MHz pedoff probe. The peak systolic and diastolic gradients through aortic isthmus were measured at rest and at the end of the exercise. A peak DG > 17 mmHg was considered significant. Mean peak systolic gradient increased from 29 to 65 mmHg with exercise. Significant DG appeared in 4 of 8 patients without any DG at rest. Among the 6 patients with non significant DG at rest, DG remained non significant in 2 and became significant in 4. For the 11 patients with MRI or CT-scan aortic arch evaluation, the specificity of significant DG at exercise was 100%, the sensitivity 75%, predictive positive value 100%, negative predictive value 60%. Apparition of a significant isthmic Doppler DG at exercise can reliably predict the hemodynamic significance of restenosis after CoA repair, as well as native narrowing of the aorta. This simple, safe and effective non-invasive method may help to identify patients requiring surgery or percutaneous stenting.