Share this page on LinkedIn
Share This Page on Google+
Share This Page on Twitter
tell someone about this page print this page
You are here: Contents > 2013 > Volume 22 Number 6 November 2013 > DEVICE EVALUATION > Risk-Adjusted Survival after Tissue versus Mechanical Aortic Valve Replacement: A 23-Year Assessment

Risk-Adjusted Survival after Tissue versus Mechanical Aortic Valve Replacement: A 23-Year Assessment

Jeffrey G. Gaca1, Robert M. Clare1, J. Scott Rankin2, Mani A. Daneshmand1, Carmelo A. Milano1, G. Chad Hughes1, Walter G. Wolfe1, Donald D. Glower1, Peter K. Smith1

1Duke University Medical Center, Durham, NC, 2Vanderbilt University, Nashville, TN, USA

Background and aim of the study: Detailed analyses of risk-adjusted outcomes after mitral valve surgery have documented significant survival decrements with tissue valves at any age. Several recent studies of prosthetic aortic valve replacement (AVR) also have suggested a poorer performance of tissue valves, although analyses have been limited to small matched series. The study aim was to test the hypothesis that AVR with tissue valves is associated with a lower risk-adjusted survival, as compared to mechanical valves.

Methods: Between 1986 and 2009, primary isolated AVR, with or without coronary artery bypass grafting (CABG), was performed with currently available valve types in 2,148 patients (1,108 tissue valves, 1,040 mechanical). Patients were selected for tissue valves to be used primarily in the elderly. Baseline and operative characteristics were documented prospectively with a consistent variable set over the entire 23-year period. Follow up was obtained with mailed questionnaires, supplemented by National Death Index searches. The average time to death or follow up was seven years, and follow up for survival was 96.2% complete. Risk-adjusted survival characteristics for the two groups

were evaluated using a Cox proportional hazards model with stepwise selection of candidate variables.

Results: Differences in baseline characteristics between groups were (tissue versus mechanical): median age 73 versus 61 years; non-elective surgery 32% versus 28%; CABG 45% versus 35%; median ejection fraction 55% versus 55%; renal failure 6% versus 1%; diabetes 18% versus 7% (p<0.01). Unadjusted Kaplan-Meier survival was significantly lower with tissue than mechanical valves; however, after risk adjustment for the adverse profiles of tissue valve patients, no significant difference was observed in survival after tissue or mechanical AVR. Thus, the hypothesis did not hold, and risk-adjusted survival was equivalent, of course qualified by the fact that selection bias was evident.

Conclusion: With selection criteria that employed tissue AVR more frequently in elderly patients, tissue and mechanical valves achieved similar survival characteristics across the spectrum of patient risk. Further studies of the relative outcomes of mechanical versus tissue valves across the spectrum of patient age seem indicated.

The Journal of Heart Valve Disease 2013;22:810-816

Risk-Adjusted Survival after Tissue versus Mechanical Aortic Valve Replacement: A 23-Year Assessment

Click the above hyperlink to view the article, right click (Ctrl click on a Mac) to open in a new browser window or tab.

Purchase this Article

Please click the button below to purchase this article. Single article purchases are provided at $50.00 per article. Upon clicking the button below, single article user account subscription details are requested and, upon successful payment, a single article user account is created. Single articles are availble in your account for seven days after purchase.