Pitfalls in Interpreting the Patient-Prosthesis Mismatch Outcome

We read with interest the article by Wilbring et al,[1] pointing out to the poor outcome following aortic valve replacement (AVR) in patients with small aortic roots, especially if they are female, obese, and older than 75 years. This study represents a large series' experience; however, we believe that there are some points which merit further discussion.

The primary concern when dealing with small aortic annulus is the fear for creating a patient-prosthesis mismatch (PPM), which is implanting too small a prosthesis for the patient's size. A stenotic prosthetic valve may cause unsatisfactory symptom relief and left ventricle mass regression, less evident improvements in functional capacity, life quality and life expectancy, ending up with congestive heart failure or sudden death, as reported by many. Unfortunately, the number of affected people is increasing with the current liberal use of small-size mechanical prostheses in aortic position. The incidental reports denying the importance of PPM or overstating the hemodynamic performance of small-size prosthetic valves encourage this trend. A small annulus may represent a challenge for the surgeon, yet can be best managed at the initial operation using relatively simple techniques. Later on, correction is often far more challenging.

Although this study focuses on small aortic valve annulus, the subject of PPM is not so much emphasized as we expected. This is partly because the analysis failed to show any association between PPM and long-term mortality/morbidity. As there may be several reasons possibly masking the real impact of PPM, the present data should be interpreted with caution to avoid a potentially misleading perception.

• Reference

• 1 Wilbring M, Alexiou K, Schumann E, Matschke K, Tugtekin SM. Isolated aortic valve replacement in patients with small aortic annulus-a high-risk group on long-term follow-up. Thorac Cardiovasc Surg 2013; 61 (5) 379-385