Aortic valve replacement with the Medtronic Mosaic bioprosthesis: a 13-year follow-up

Background: This study evaluated the long-term clinical performance of the Mosaic bioprosthesis (Medtronic Inc, Minneapolis, MN) after aortic valve replacement.

Methods: From 1995 to 2008, 178 patients (48 women; mean age, 74±6 years) had aortic valve replacement. Mean functional class was 2.3±0.5, and 157 patients (88%) were in sinus rhythm. Prosthetic sizes were 23 mm in 98 patients and 25 mm in 66. Follow-up was completed in December 2009 with a cumulative duration of 1,015 patient/years (mean, 5.7±3.5 years, maximum, 13.7 years).

Results: Early mortality was 4%, none being valve-related; of 38 late deaths 7 were valve-related. Actuarial survival at 13 years was 48%±8%. Mean functional class of current survivors was 1.2±0.6. Six embolic episodes occurred and four cases of endocarditis, with respective actuarial freedom of 92%±5% for embolism and 97%±2% for endocarditis at 13 years. Four patients required reoperations for endocarditis and 2 for structural deterioration. Actuarial freedom from structural deterioration and from reoperation for all causes was 89%±7% and 86%±7% at 13 years, with an actuarial freedom from prosthesis-related deaths of 86%±5%. Results of echocardiographic evaluation at 1 year were mean peak gradient, 20±6 mm Hg and mean effective orifice area index, 1.07±0.21 cm2/m2 for size 23 mm and 22±6 mm Hg and 1.11±0.26 cm2/m2 for size 25 mm; at 10 years, mean peak gradient and mean effective orifice area index were 28±13 mm Hg and 1.01±0.19 cm2/m2 for size 23 mm and 26±8 mm Hg and 1.08±0.18 cm2/m2 for size 25 mm.

Conclusions: The Mosaic bioprosthesis showed good overall performance, with low incidence of structural valve deterioration and hemodynamic stability in the long-term. Expected increased durability of this device should be verified at longer follow-up intervals.