Acute and follow-up intravascular ultrasound findings after balloon dilation of coarctation of the aorta

Background: The study objective was to examine the vascular wall changes caused by balloon dilation of coarctation of the aorta (CoA) acutely and at short-term follow-up using intravascular ultrasound imaging. Intravascular ultrasound has been valuable in assessing the vessel wall changes in coronary and peripheral arteries after balloon dilation, often with more detail than angiography. Methods and Results: Intravascular ultrasound imaging, using 4.8F, 20-MHz or 6.2F, 12.5-MHz catheters on either Diasonics or HP scanners, was performed in 17 patients during balloon angioplasty for native (n=12) and recurrent (n=5) CoAs. Nine patients were also studied at the time of follow- up cardiac catheterization 28.1±18.0 months after angioplasty. Immediately after dilation, the mean pressure gradient across the CoA decreased from 42.9±16.4 to 9.0±5.4 mm Hg (P<.001) and the mean diameter of the coarcted segment increased from 4.4±1.9 to 7.9±2.4 mm (P<.001). An intimal tear or flap was noted by ultrasound in 12 of the 12 native CoAs and 4 of the 5 recoarctations. In contrast, only 6 of the native CoAs and 2 of the recoarctations had an intimal flap or dissection detected by angiography. At follow-up, the residual pressure gradient did not significantly change from that measured immediately after dilation, but the CoA diameter increased from 7.8±1.5 to 9.9±2.3 mm (P<.01). No aneurysms were detected. Four of the 9 patients showed ultrasonic and angiographic evidence of healing and remodeling with diminution in size or disappearance of the intimal tears. Conclusions: There is a high incidence of intimal tears and dissections immediately after balloon angioplasty for native and recurrent CoAs. Intravascular ultrasound is more sensitive than angiography in detecting the vascular wall changes. Even significant intimal tears are not necessarily associated with aneurysm formation, and many decrease in size or disappear at short-term follow-up.