Invited commentary

Abstract

The ultimate test of a new heart valve prosthesis remains the implantation of the device in humans. This is not without risk, and unexpected catastrophic results can be obtained in spite of extensive pre-clinical testing. Therefore it is a relief to see the report of a first clinical trial demonstrating uneventful early results. To justify such clinical implantation of newly developed heart valves, one expects at least significant advantages on the existing and generally accepted prostheses. In case of the newly designed low-profile Medtronic Advantage valve (Medtronic, Inc, Minneapolis, MN), there could be superior hemodynamics and reduced thrombogenicity. The present study [1Guenzinger R. Eichinger W.B. Botzenhardt F. et al.Rest and exercise performance of the Medtronic advantage bileaflet valve in the aortic position.Ann Thorac Surg. 2005; 80: 1319-1326Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar] reveals that the Medtronic Advantage valve performs well hemodynamically as demonstrated by low mean pressure gradients, large effective orifice areas, and indices. Furthermore, the authors performed hemodynamic studies during treadmill exercise 1 year after valve replacement, the ultimate test of heart valve performance. They also found a low incidence of patient–prosthesis mismatch and a significant regression of left ventricular (LV) mass 1 year after valve replacement. The authors are to be congratulated not only for their carefully performed study, but also for their realistic interpretation of the results. Indeed, a mean pressure gradient ranging from 10.8 to 20.0 mm Hg across all valve sizes during treadmill exercise at 100 W workload is excellent but not superior to the results of existent bileaflet valves. The same holds true for effective orifice area index (EOAI) values between 0.93 and 1.37 cm2/m2, the low incidence of patient-prosthesis mismatch, and an 18% reduction of LV mass at 1 year. It is unquestionably true that “second generation” bileaflet heart valves perform better than their “first generation” counterparts and that actual heart valves designs did “a good job.” In a comparable series of patients for example, we observed EOAI values between 0.60 to 0.92 (across all valve sizes, including size 19) for the older St. Jude Standard bileaflet valve versus 0.91 to 1.37 cm2/m2 for the actual St. Jude Regent valve (St. Jude Medical, St. Paul, MN). We may confirm the conclusion of the present study that this new bileaflet valve has an excellent hemodynamic profile, but we feel that the advantage of the Medtronic Advantage valve on the existing second generation bileaflet heart valves remains to be elucidated.