Does the type of prosthesis influence the incidence of permanent pacemaker implantation following isolated aortic valve replacement

Background: The incidence of conduction disorders requiring permanent pacing (PPM) in patients operated on for aortic valve replacement (AVR) has been reported to be 5.7%. However, perioperative risk predictors for PPM following AVR are not well characterized and debate exists regarding selection of the prosthesis-type most likely to minimize this incidence. The aim of the study was to assess whether the type of the prosthesis used influences the prevalence of PPM following aortic valve replacement. Methods: A total of 782 consecutive patients with predominant aortic stenosis accepted for isolated non-emergent AVR were studied over a 3 year period; of which 305 patients ( Group A) received mechanical prostheses, 335 received stented tissue prostheses ( Group B), and the remaining 142 received stentless tissue valves ( Group C). A stepwise logistic regression analysis was used to identify the independent predictors for PPM and statistical significance was accepted at a level of P <.05. Results: Univariate and multivariate analyses showed a significant relationship between the preoperative factors ( poor ejection fraction < 35%; P <.001), left atrial enlargement (LAE; P <.001) and left bundle branch block (LBBB; P <.001), the perioperative variables ( bypass time > 100 minutes with x-clamp time > 70 minutes; P <.001) and the incidence of PPM. Conclusions: The proposed predictive model correlated highly with actual pacemaker use, suggesting that the requirement for PPM results from either operative trauma or increased ischemic burden and the incidence of PPM is independent of prosthesis-type implanted.