Aortic valve stenosis is prevalent in the elderly and valve replacement for severe symptomatic obstruction improves symptoms and prolongs life. However, some patients have persistent symptoms after intervention because the functional valve area of the prosthetic valve is too small for the patient's body size–a situation termed patient-prosthesis mismatch (PPM). The hemodynamics of PPM have been well described but the actual clinical impact of PPM is controversial. In this issue of Heart, Dr Price and colleagues (see page 1099) report that PPM was associated with decreased survival and persistent symptoms only in patients with a low left ventricular ejection fraction who were under age 70 years at the time of valve surgery. In older adults, although PPM was associated with impaired regression of LV hypertrophy, PPM was not associated with increased mortality or heart failure symptoms (figure 1). This data has important implications for clinical management suggesting that additional procedures to allow implantation of a larger prosthesis may not be necessary in older adults or in younger patients with normal left ventricular function. On Heart online you also can listen to …