Left ventricular mass regression after aortic valve replacement with the Mosaic bioprosthesis

Background and aims of the study: The study aim was to evaluate the hemodynamic performance and extent of left ventricular (LV) mass regression after aortic valve replacement (AVR) with the Mosaic bioprosthesis within the first postoperative year. Methods: Between 1994 and 1999, 366 patients (203 males, 163 females) underwent AVR with the Mosaic bioprosthesis at five centers in Europe. Mean age at implant was 71.1 years (range: 34.5-86.8 years). LV mass assessment and hemodynamic evaluation were performed using transthoracic echocardiography within six days postoperatively, after six months, and at annual intervals thereafter. Results: LV mass index decreased significantly in patients with valve sizes 21 to 27 mm, from 184.4 ± 56.2 g/m² postoperatively to 157.3 ± 45.5g/m² after one year (14.7% decrease). The 19-mm valve group did not show significant LV mass index reduction (from 210.4 ± 39.4 to 195.0 ± 59.4g/m²; 7.3%). Patients with significant LV mass index regression had survival benefits after seven years. Mean pressure gradients after one year were 16.0 ± 4.3, 14.2 ± 5.4, 12.8 ± 5.3, 11.1 ± 4.0 and 10.5 ± 3.7 mmHg for 19, 21, 23, 25 and 27 mm valves, respectively. Conclusion: Implantation of the Mosaic bioprosthesis resulted in a significant regression of LV mass for the valves sizes 21 to 27 mm, corresponding to very low pressure gradients for a stented bioprosthesis.