Operative Management – Patient-Prosthesis Mismatch

The main objective of aortic valve replacement (AVR) is to relieve left ventricular (LV) burden and normalized LV mass (LVM). During AVR, many surgeons make final decision to select the size of the prosthetic valve based on intraoperative measurement. It is ideal to place an aortic prosthesis that is appropriately sized to the patient. However, this is not always possible owing to insufficient aortic annular dimensions. Patients receive a prosthesis that is too small in relation to their body size have persistent abnormally high gradients across the valve and may even show deterioration of symptoms and hemodynamics after AVR. Rahimtoola first described the concept of patient-prosthesis mismatch (PPM), which was defined as existing “when the effective prosthetic valve area, after insertion into the patient, is less than that of a normal valve” 1. The optimal prosthetic valve should have several characteristics, including a sufficiently large effective orifice area (EOA) with a reduced transvalvular pressure gradient around zero, long-term durability, and anticoagulability. There is no optimal, commercially available prosthesis. The normal aortic valve has 3.0-4.5 cm2 of EOA, but this is rarely achieved with present commercially available prostheses, which means that the result of AVR may be suboptimal in many patients. In general, PPM is considered to be present when an indexed EOA (IEOA) adjusted for body surface area (BSA) is <0.85 cm2/m2 2-4. Although, many studies have shown that PPM adversely affects survival and postoperative cardiac function 2-4, many studies contradict these findings 5-12. Thus, there is considerable controversy regarding the effects of PPM on survival and postoperative recovery of cardiac functions. Patients with a small aortic annulus is still challenging and usually require several surgical measures to minimize the PPM, such as use of supra-annular implantation technique, high-performance prostheses, aortic annular enlargement, or the Ross procedure. The surgical strategy is determined based on the individual patient’s conditions, including the size of the aortic annulus, patient’s age, BSA, preoperative activity level, and ventricular function. Avoiding the risk of severe PPM defined as an IEOA <0.70 cm2/m2, which may prevent symptom resolution and regression of left ventricular hypertrophy and may adversely affect late cardiac events and survival, must always be considered by taking appropriate surgical strategies, but, it is more important