Patient-prosthetic mismatch (PPM) occurs when the effective flow area for a normally functioning prosthetic valve is smaller than needed to provide an adequate cardiac output at rest and with exercise in that specific patient. Current recommendations for avoiding PPM focus on implantation of a valve adequate to the patient's body size. There has been little attention to avoiding PPM by ensuring the patient's body size is appropriate, an approach that may become relevant with the increasing prevalence of obesity in many countries. PPM is a particular problem in patients with congenital heart disease because the patient's body size often continues to increase, due to normal growth, after the prosthetic valve is implanted. Thus, an adequate size prosthetic valve at the time of implantation may be too small once the patient reaches adult stature (figure 1). PPM has deleterious physiologic consequences and may be associated with adverse clinical outcomes. In adults with acquired valve disease, aortic valve PPM is associated with persistent left ventricular hypertrophy, reduced exercise capacity and higher mortality rates in some patient subsets. However, the impact of PPM in adults with congenital heart disease (ACHD) has not previously been studied.

In a Dutch registry of ACHD patients with prosthetic heart valves, Pieper and colleagues (see page 107) found that PPM was present in 42% of 207 ACHD patients with a prosthetic aortic valve. Severe PPM, defined as an indexed effective orifice area ≤0.65 cm²/m …