Patient-Prosthesis Mismatch in Contemporary Small-Size Mechanical Prostheses Does Not Impact Survival at 10 Years

Background: The effect of PPM in mechanical prostheses on long-term survival is not well-established. Methods: Patients who received a 21 mm or smaller aortic valve between 2000 and 2011 were retrospectively analyzed (n = 416). Propensity matching was used in order to account for baseline differences in patient subgroups (PPM vs. no PPM; severe PPM vs. no severe PPM). Results: Five- and ten-year survival was 78 +/- 3.52% and 64.51 +/- 4.51% in patients with PPM, versus 83.3 +/- 3.12% and 69.37 +/- 4.36% in patients without (p = 0.28) when analyzed at 10.39 +/- 5.25 years after the primary procedure. Independent risk factors for impaired survival, after matching, were age, serum creatinine, and severe pulmonary hypertension. Five- and ten-year survival in patients with severe PPM was 73.34 +/- 6.01% and 61.76 +/- 8.17%, respectively, versus 74.72 +/- 5.68% and 67.50 +/- 7.09% in those without (p = 0.49), at 8.82 +/- 5.17 years after SAVR. Age was the only independent variable that influenced long-term survival when severe PPM was added to the model. Conclusions: PPM or severe PPM does not impact long-term survival up to 10 years in mechanical valve recipients when matching for preoperative variables.