Clinical impact of patient-prosthesis mismatch after aortic valve
replacement with a mechanical or biological prosthesis
Objectives: Patient-prosthesis mismatch (PPM) may impair
functional capacity and survival after aortic valve replacement (AVR). A
mechanical prosthesis tends to have less PPM than a biological
prosthesis, but these differences in clinical outcomes remain unclear.
This study aimed to investigate the impact of PPM on long-term survival
and quality of life (QoL) after mechanical and biological AVRs.
Methods: The presence of PPM was defined in 595 consecutive
patients who had undergone isolated AVR. Patients were divided into two
groups according to whether they had received a biological or mechanical
prosthesis. The groups with and without PPM present were compared with
regard to baseline characteristics, operative characteristics, survival,
severe complications, freedom from angina and QoL up to 6 years of
follow-up. PPM calculation was performed using the EOA value provided by
the manufacturer for every prosthesis divided by the patient’s body
surface area. Results: The moderate-to-severe PPM rates were
69.8% and 3.7% after biological and mechanical prostheses
implantation, respectively. Patients with a biological prosthesis
implanted had mean survival significantly shorter in the PPM group (50.2
months, 95% confidence interval [CI] 45.2-55.3) when compared to
the no-PPM group (60.1 months, 95% CI 55.7-64.4) (p = 0.035). In the
mechanical prosthesis group, there was no difference in mean survival
between the PPM group (66.6 months, 95% CI 58.3-74.9) when compared to
the no-PPM group (64.9 months, 95% CI 62.6-67.2) (p = 0.50). The
physical score of the QoL questionnaire was significantly lower in the
PPM group when compared to the no-PPM group with a biological prosthesis
(39.4 ± 8.4 vs. 45.7 ± 10.1, p < 0.001) compared to patients
with a mechanical prosthesis (43.9 ± 9.4 vs. 46.9 ± 8.3, p = 0.18).
Conclusions: PPM is common after biological valve implantation
and significantly impacts long-term survival and QoL. If the risk of PPM
after implantation of a biological prosthesis is suspected, prospective
strategies to avoid PPM at the time of operation are warranted.