Measurements to Detect Signicant Coarctation of the Aorta

Evaluation for the presence and severity of coarctation of the aorta (CoA) by two-dimensional echocardiography alone can be difcult. The purpose of this study was to use Doppler velocity and pressure gradient half-time in systole and diastole to estimate CoA severity. Doppler echocardio-grams of children with suspected CoA and either an aortic angiogram or thoracic magnetic resonance imaging (MRI) performed within 1 month of the echocardiogram were evaluated. Patients with patent ductus arteriosus, signicant aortic insufciency, long tubular CoA, or CoA outside the thorax were excluded. Measured Doppler variables, indexed for heart rate, included systolic velocity half-time (sVHTi), diastolic velocity half-time (dVHTi), systolic pressure half-time (sPHTi), and diastolic pressure half-time (dPHTi). For each of these variables, sensitivity and specicity to detect a signicant CoA were determined. A signicant CoA was dened as a ratio of the CoA diameter to the diaphragmatic aortic diameter of 0.5 as imaged by MRI or angiography. Indexed systolic velocity and pressure half-times were found not to be signicant predictors for CoA. For the Doppler parameter dVHTi, using a critical value of 200 msec indexed, we found a positive predictive value of 87 % and a negative predictive value of 80%. The parameter dPHTi, using a critical value of 7