Valve Prosthesis Patient Mismatch

The problem of VPPM needs to be addressed in patients with small aortic annuli. The options for such patients are implantation of stentless valves or of homografts. The enlargement of the aortic root could also be performed. These techniques, however, can be very demanding. The implantation of a stented valve is easier but carries the risk for VPPM.

The type of stentless valves and their implantation techniques are described very briefly. Of more importance are the postoperative results. These are difficult to compare for two reasons:

1) Stentless valves do no form a homogenous group.

2) Patients series can differ in age, co-morbid conditions and other characteristics.

Therefore, patients baseline characteristics should be described as completely as possible. The postoperative results for stentless valves seemed to be comparable with those of stented counterparts. For both, stented ans stentless devices, patient related factors have the most impact on the outcome.

The presence or absence of VPPM could be related to hemodynamic parameters, such as EOAI and TVG. This relationship, however, is not straightforward. Moreover, VPPM needs to be defined and graded properly. VPPM seems only to be clinically relevant in patients with a decreased LVF. In patients with a normal LVF, VPPM does not seem to affect the postoperative outcome in terms of survival, LVM regression and freedom of CHF.

The development of SVD could be held responsible for a recurrent hemodynamic burden on the LV. This burden could play a role in reappearance of LVH. SVD was thought to occur less in stentless valves, since turbulence and hence stress on the leaflets would be reduced. In some stentless devices this seems not to be the case.

Availability of 15 year results is needed, but this is not easy to obtain since the median age in patient series is rather high.

Keywords: Aortic root enlargement, effective orifice area, left ventricular function, left ventricular mass, stentless heart valves, structural valve degeneration, survival, transvalvular gradients, valve prosthesis patient mismatch, valve size.