TIME-COURSE OF DIMENSION AND FUNCTION OF THE AUTOLOGOUS PULMONARY ROOT IN THE AORTIC POSITION

Although the autologous, fully vital, and compatible pulmonary root th eoretically offers the prospect of an ideal aortic valve substitute, t his type of replacement is performed in only a few centers. Major conc ern relates to the fate of root dimension and function in the systemic circulation and is largely unknown. To investigate the fate of the ao rtic root, we conducted echocardiographic examinations of eight freest anding pulmonary roots used for aortic valve replacement in adults. Th e studies were performed at discharge from the hospital and up to 21 m onths (mean 12.5 +/- 6.6 months) after the operation, as well as in 26 matched control subjects. There were no significant differences betwe en the first and second postoperative studies regarding the root diame ter (mean 26.6 +/- 2.1 mm and 27.6 +/- 2.6 mm, respectively), which wa s within control limits, the maximum transvalvular pressure gradient ( mean 4.6 +/- 1.2 mm Hg and 6.6 +/- 2.1 mm Hg, respectively), the maxim um leaflet separation (mean 22.1 +/- 1.4 mm and 22.1 +/- 1.8 mm, respe ctively), and the degree of insufficiency. At the first study, grade I aortic regurgitation was found in four patients and grade I-II in one patient. Regurgitation increased slightly in one patient with an abno rmal leaflet. In three patients primary grade I regurgitation disappea red. These data suggest that the pulmonary root in the aortic position can withstand systemic circulation without changes in dimension and f unction for up to 21 months. Furthermore, some evidence is provided to indicate that in certain cases the viable autograft may adapt to syst emic pressure, as indicated by the disappearance of primary regurgitat ion.