1. Prosthetic Heart Valves: Objective Performance Criteria Versus Randomized Clinical Trial 
Gary L. Grunkemeier, PhD, Ruyun Jin, MD, Albert Starr, MD 
The Annals of Thoracic Surgery 
Volume 82, Issue 3, Pages (September 2006)
DOI: /j.athoracsur
Copyright © 2006 The Society of Thoracic Surgeons Terms and Conditions

2. Fig 1
Cumulative patient-years of follow-up (smooth, almost identical curves, indexed by the left vertical axis) and the number of major leaks (dashed step functions, indexed by the right vertical axis) for the Silzone and Standard arms of the Artificial Valve Endocarditis Reduction Trial. The scale of the left axis is 100 times that of the right axis, so that the cumulative leak curve from a valve with a rate of 1 leak per 100 patient-years (1%/year) would fall directly on top of its cumulative follow-up curve. The dotted horizontal line indicates the objective performance criteria follow-up requirement of 800 patient-years, and the unshaded area on the left indicates the follow-up observed by that time, during which there were 14 and 3 leaks in the Silzone and Standard valve arms of the study, respectively (height of the black circles, as read on the right vertical axis).
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2006 The Society of Thoracic Surgeons Terms and Conditions

3. Fig 2
Major leak rates with 90% confidence intervals (horizontal axis), after 800 valve-years, for various numbers of observed events (vertical axis). The dashed vertical line indicates the objective performance criteria (OPC) of 0.6%/year for major paravalvular leak. The Food and Drug Administration criterion for approval is that the upper limit of the confidence interval is less than two times the OPC (the solid vertical line). The Silzone arm (14 leaks) of the study violates the acceptance criterion, and the Standard arm (3 leaks) satisfies it (identified by the two thicker horizontal lines). Note that the upper limit of a two-sided 90% confidence interval, as plotted in this figure, is the same as the limit of a one-sided 95% confidence interval, as required by the FDA guidance document.
The Annals of Thoracic Surgery  , DOI: ( /j.athoracsur )
Copyright © 2006 The Society of Thoracic Surgeons Terms and Conditions