LEFT PULMONARY-ARTERY KINKING CAUSED BY OUTFLOW TRACT DILATATION AFTER TRANSANNULAR PATCH REPAIR OF TETRALOGY OF FALLOT

Background. Stenosis of the branch pulmonary arteries after tetralogy of Fallot repair can result from several mechanisms. In patients with free pulmonary regurgitation and right ventricular dilatation after tr ansannular patch repair, we have observed that the pulmonary outflow t ract can dilate and elongate craniad and rotate to the left, resulting in kinking and obstruction of the previously normal left pulmonary ar tery. Methods. Ten patients referred for reoperation after tetralogy r epair with severe pulmonary regurgitation and right ventricular outflo w tract dilatation were found to have left pulmonary artery kinking. I n 8 of these patients kinking was the sole or partial cause of left pu lmonary artery obstruction, whereas there was no documented obstructio n in the other 2. All patients underwent right ventricular outflow tra ct reconstruction and left pulmonary artery repair with removal of the redundancy at the kink point. Patching alone is not an effective meth od of repair in this condition, because the mechanism of obstruction i s not corrected and the patch material can become redundant and lead t o recurrent obstruction. Results. All patients underwent successful pu lmonary outflow tract reconstruction. Left pulmonary artery kinking wa s corrected in all patients, and relief of obstruction was attained in the 8 patients with stenosis. At follow-up ranging from 9 to 58 month s, no patient has evidence of recurrent left pulmonary artery stenosis . Conclusions. Left pulmonary artery kinking should be suspected at lo ng-term follow-up after tetralogy repair in patients with significant pulmonary regurgitation and right-sided dilatation, even if previous e valuations showed no evidence of left pulmonary arterial abnormality. Because unilateral obstruction caused by kinking may lead to asymmetri c pulmonary flow it can exacerbate pulmonary regurgitation and right v entricular dilatation, in effect accelerating the processes that led t o kinking in the first place. Kinking can be relieved successfully wit h the techniques described in this report. (C) 1998 by The Society of Thoracic Surgeons.