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 change s caused by balloon dilation of coarctation of the aorta (CoA) acutely and at short-term follow-up using intravascular ultrasound imaging. I ntravascular ultrasound has been valuable in assessing the vessel wall changes in coronary and peripheral arteries after balloon dilation, o ften with more detail than angiography. Methods and Results Intravascu lar 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 duri ng balloon angioplasty for native (n=12) and recurrent (n=5) CoAs. Nin e patients were also studied at the time of follow-up cardiac catheter ization 28.1+/-18.0 months after angioplasty. Immediately after dilati on, 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 s egment increased from 4.4+/-1.9 to 7.9+/-2.4 mm (P<.001). An intimal t ear 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 an giography. At follow-up, the residual pressure gradient did not signif icantly 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 aneu rysms were detected. Four of the 9 patients showed ultrasonic and angi ographic evidence of healing and remodeling with diminution in size or disappearance of the intimal tears. Conclusions There is a high incid ence of intimal tears and dissections immediately after balloon angiop lasty for native and recurrent CoAs. Intravascular ultrasound is more sensitive than angiography in detecting the vascular wall changes. Eve n significant intimal tears are not necessarily associated with aneury sm formation, and many decrease in size or disappear at short-term fol low-up.