THE 20 MM MEDTRONIC-HALL PROSTHESIS IN THE SMALL AORTIC ROOT

Background and aims of the study: The choice of prosthesis becomes cru cial in the narrow aortic annulus. The 20 mm Medtronic Hall valve has a reduced sewing ring that fits in an annulus where only a 19 mm valve would fit. This study assesses the hemodynamic performance of this pr osthesis at rest and at exercise, and compares it with two 19 mm mecha nical prostheses. Materials and methods: Forty-two patients were studi ed by Doppler echocardiography, a mean of 34 months following surgery. Twenty-six had a 19 mm prosthesis implanted (12 standard St. Jude Med ical and 14 Monostrut valves) and 16 had a 20 mm Medtronic Hall. Param eters studied were peak velocity and transvalvular gradient, both at r est and at exercise, effective orifice area and valve index. Results: No differences were found between the two 19 mm valves, but when compa red with the Medtronic Hail valve at rest, this valve showed significa ntly lower peak velocity and gradient (2.9 vs. 3.3 m/sec, p<0.01, and 17 vs. 23 mmHg, p<0.003, respectively) and higher effective orifice ar ea and valve index (1.3 vs. 1.0 cm(2), p<0.01 and 0.81 vs. 0.62 cm(2), p<0.006, respectively). There were also significant differences under exercise. Conclusions: The 20 mm Medtronic Hall prosthesis shows a si gnificantly better hemodynamic performance, both at rest and under exe rcise, than other, 19 mm mechanical prostheses and represents a superi or choice in valve replacement with a small aortic root.