eComment. The current bioprosthesis of choice for aortic valve replacements.

ference in postoperative aortic valve area, maximum velocity across the valve and mortality. Pelletier et al. [8] performed a cohort study comparing 878 CE porcine and 715 Ionescu-Shiley, CE and Mitroflow bovine valves in AVR, MVR or MR from 1976–88. It showed similar late survival rates and clinical improvement. However, the freedom from all valve-related complications was significantly better in porcine valves. Eichinger et al. [9] conducted an RCT comparing 68 MM porcine valve and 70 CE Perimount bovine valves in AVR in the years 2000 to 2002. There was no difference in patient– prosthesis mismatch. The bovine valve had lower mean pressure gradient at rest and during exercise 10 months after operation. Walther et al. [10] carried out an RCT on 100 patients from 2000–2003 comparing MM porcine and Perimount bovine valves. Transvalvular blood flow velocity and mean pressure were assessed. Both valves showed acceptable haemodynamic function with significant LV mass regression with overall better haemodynamic profile in bovine valves. Czer et al. [11] conducted a cohort study on 656 patients comparing Hancock standard and CE porcine valves with St Jude Medical bileaflet bovine valves in AVR, MVR or MR positions from 1976–1984. Both porcine and bovine valves had a similar mortality rate. Porcine valves had higher structural failure rates with higher reoperation rates. Bovine valves showed better functional status postoperatively. Dalmau et al. [12] performed an RCT in Spain comparing 43 MM porcine valves with 43 Edward Perimount Magna bovine valves in AVR position. Mean pressure gradient, EOA and LV mass regression were examined. Bovine valves showed better haemodynamic function with lower patient–prosthesis mismatch prevalence at 1-year follow-up. Borger et al. [13] performed a cohort study comparing 57 Medtronic Hancock II porcine valves with 57 CE Perimount Magna bovine valves in AVR and/or concomitant procedures in 2004 to 2005. Bovine valves showed better peak and mean transvalvular gradients with lower patient–prosthesis mismatch. Wagner et al. [14] compared 50 CE Perimount bovine valves, 70 Perimount Magna bovine valves, 44 MM porcine valves and 28 Soprano bovine valves through a cohort study in Germany. They demonstrated that generally bovine valves had better haemodynamic performance compared with porcine valves. Suri et al. [15] conducted an RCT from 2004 to 2006 examining 76 Edwards Perimount bovine and 76 MM Porcine valves. Despite small differences in haemodynamic performance, both valves had similar LV regression after 1 year follow-up. An RCT performed by Dalmau et al. [16] from 2004 to 2006 comparing 54 Edwards Perimount Magna bovine and 54 MM showed superior haemodynamic function in bovine valves leading to LV regression. Patients with bovine valves also had better overall survival rate at 5 years.