RADIOGRAPHIC DETECTION OF SINGLE STRUT LEG SEPARATIONS AS A PUTATIVE BASIS FOR PROPHYLACTIC EXPLANTATION OF BJORK-SHILEY CONVEXO-CONCAVE HEART-VALVES

Cineradiography, using higher kVp and two or more specified profiles f or each outlet strut leg, was used to evaluate Bjork-Shiley convexo-co ncave (C/C) heart valves with epidemiologically defined > 0.1% per yea r estimated fracture rates. Among 828 mitral valves, eight radiographs were assessed as definite single leg separations (SLS) and 23 were re ad as probable SLS. Explantation confirmed SLS in 24 valves; 4 probabl es were false positives, and 3 patients with probable SLS ratings deci ded against explantation. Four patients with SLS died, an operative mo rtality of 14%. Only 23 mitral and 6 aortic valves receiving ratings r anging from apparently normal to suspicious have become available for verification; 1 rated apparently normal was found to have a SLS. Two p atients experienced fatal fractures and 1 SLS valve was explanted 3 to 15 months after apparently normal x-ray studies; it cannot be known i f a SLS was or was not present at the time of these examinations. As 9 7% of negatively rated valves remain in situ, the sensitivity of the t est is similarly not known. Only 1 SLS has been detected among 136 aor tic valves. Uncertainty about test accuracy and SLS progression condit ion the clinical utility of radiographic SLS detection, particularly w ith respect to assurance from apparently normal readings. However, rad iographic identification of an SLS substantially enhances epidemiologi cally derived risk categorization as a basis for consideration of prop hylactic replacement for the approximately 12,000 valves with a > 0.1% estimated annual fracture risk, currently thought to be implanted in living patients.