Distensibility of the pulmonary autograft under systemic pressure.

Background And Aims Of The Study: Although the Ross procedure has recently been recognized as one of the best replacements of the aortic valve, regurgitation has occasionally been observed with dilatation of the sinotubular junction (STJ) and/or basal ring (BR). This study was designed to evaluate the native distensibility of the free pulmonary root under systemic pressure.

Methods: Pulmonary arterial grafts (n = 7) were taken from pig hearts and pressurized (20-100 cmH2O) with crystal sensors attached around the STJ and BR. Dimensions of the STJ and BR were measured using a digital 3-D ultrasonic sonomicrometer at different pressures (20-100 cmH2O) with and without the STJ and/or BR plicated with felt-strip to prevent overdistension. Valve insufficiency was evaluated macroscopically and endoscopically.

Results: All grafts showed no obvious valve insufficiency at 20 cmH2O. Grafts pressurized at 100 cmH2O showed 125+/-6% and 113+/-5% enlargement of dimensions compared with baseline (20 cmH2O) data at the STJ and BR respectively, with recognizable insufficiency. When the STJ was plicated to prevent overdistension at 100 cmH2O with less dilated BR (106%), mild excentric insufficiency was observed. In case of the BR plicated at 100 cmH2O with a less dilated STJ (112%), central slight regurgitation was observed. Both the STJ and BR plications resulted in no recognizable regurgitation.

Conclusion: Free pulmonary arterial grafts were remarkably enlarged under systemic pressure with recognizable valve insufficiency; this could be prevented by maintaining the original dimensions of the graft STJ and BR.