2 research outputs found
Longâterm surveillance biopsy: Is it necessary after pediatric heart transplant?
Due to limited and conflicting data in pediatric patients, longâterm routine surveillance endomyocardial biopsy (RSB) in pediatric heart transplant (HT) remains controversial. We sought to characterize the rate of positive RSB and determine factors associated with RSBâdetected rejection. Records of patients transplanted at a single institution from 1995 to 2015 with >2Â year of postâHT biopsy data were reviewed for RSBâdetected rejections occurring >2Â year postâHT. We illustrated the trajectory of significant rejections (ISHLT Grade â„3A/2R) among total RSB performed over time and used multivariable logistic regression to model the association between time and risk of rejection. We estimated KaplanâMeier freedom from rejection rates by patient characteristics and used the logârank test to assess differences in rejection probabilities. We identified the bestâfitting Cox proportional hazards regression model. In 140 patients, 86% did not have any episodes of significant RSBâdetected rejection >2Â year postâHT. The overall empirical rate of RSBâdetected rejection >2Â year postâHT was 2.9/100 patientâyears. The percentage of rejection among 815 RSB was 2.6% and remained stable over time. Years since transplant remained unassociated with rejection risk after adjusting for patient characteristics (ORÂ =Â 0.98; 95% CI 0.78â1.23; PÂ =Â 0.86). Older age at HT was the only factor that remained significantly associated with risk of RSBâdetected rejection under multivariable Cox analysis (PÂ =Â 0.008). Most pediatric patients did not have RSBâdetected rejection beyond 2Â years postâHT, and the majority of those who did were older at time of HT. Indiscriminate longâterm RSB in pediatric heart transplant should be reconsidered given the low rate of detected rejection.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147767/1/petr13330_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/147767/2/petr13330.pd
Microtextured Materials for Circulatory Support Devices: Preliminary Studies
Thromboembolic events (TE) associated with circulatory support devices are a major source of mortality and morbidity. Clinically, the lowest TE rates are claimed with devices that incorporate textured blood-contacting materials. The textured materials currently used in circulatory assist devices are composed of small, attached fibers that form the boundaries of connected cavities. These cavities entrap blood components to form a \ neointimal\ layer, which is believed to minimize thromboembolic events. We believe that the three-dimensional surface topography of blood-contacting materials is a major controlling factor in the formation of a stable neointimal layer upon the material. Particle-cast cavities were used to form geometric features in segmented polyurethane. This microtextured material was incorporated as part of a flexible blood-contacting surface in a blood pump that was implanted as a left ventricular assist device in calves. The structure, thickness, stability, and development of the neointimal layer were then evaluated. These preliminary studies have shown that a stable neointimal layer can be formed upon the particle-cast surfaces. The results also indicate that the cavity size on the particle-cast surfaces has a significant effect on neointimal adhesion. The methods employed can be used in the design of future circulatory support devices. © American Society of Artificial Internal Organs