Biological Versus Mechanical Aortic Prosthesis? A Nineteen-year Comparison in a Propensity-matched Population
Departments of Cardiovascular Surgery and Pathology, University of Padua Medical School, Padua, Italy
Background and aim of the study: The choice of
aortic valve substitutes remains controversial. Malfunction and systemic
valve complications affect the results of mechanical and tissue valves.
Two devices - the Sorin Monocast (tilting disk) valve and the Hancock
Standard valve were compared, the study aim being to determine whether
the valve model is a marker or a causal influence of poor outcome after
aortic valve replacement (AVR).
Meier freedom from valve-related mortality was 84% (group
S) and 82% (group HcK) (p = NS), while overall survival was 42% (group
S) and 35% (group HcK) (p = NS). Structural valve deterioration (SVD)
was the major cause of reoperation in the HcK group. The 19-year freedom
from all valve-related complications was 43% (group S) versus 19% (group
HcK) (p = 0.0001). By propensity score, 61% of the valve replacements
(247/405) were perfectly matched for available risk factors, with an
equal distribution of risk covariates. When SVD and reoperation due to
SVD were excluded, survival and freedom from all valve-related complications
of the matched patients were identical between the prostheses under comparison.