Browsing by Author "Chang, Yuchiao"

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    International, multicenter evaluation of a new D-dimer assay for the exclusion of venous thromboembolism using standard and age-adjusted cut-offs.
    (Thrombosis research, 2018-04-05) Parry, Blair Alden; Chang, Anna Marie; Schellong, Sebastian M; House, Stacey L; Fermann, Gregory J; Deadmon, Erin K; Giordano, Nicholas J; Chang, Yuchiao; Cohen, Jason; Robak, Nancy; Singer, Adam J; Mulrow, Mary; Reibling, Ellen T; Francis, Samuel; Griffin, S Michelle; Prochaska, Jürgen H; Davis, Barbara; McNelis, Patricia; Delgado, Joao; Kümpers, Philipp; Werner, Nikos; Gentile, Nina T; Zeserson, Eli; Wild, Philipp S; Limkakeng, Alexander T; Walters, Elizabeth Lea; LoVecchio, Frank; Theodoro, Daniel; Hollander, Judd E; Kabrhel, Christopher
    We sought to determine the test characteristics of an automated INNOVANCE D-dimer assay for the exclusion of pulmonary embolism (PE) and deep venous thrombosis (DVT) in emergency department (ED) patients using standard and age-adjusted cut-offs.Cross-sectional, international, multicenter study of consecutive patients with suspected DVT or PE in 24 centers (18 USA, 6 Europe). Evaluated patients had low or intermediate Wells PE or DVT scores. For the standard cut-off, a D-dimer result <500 ng/ml was negative. For the age adjusted cut-off, we used the formula: Age (years) ∗ 10. The diagnostic standard was imaging demonstrating PE or DVT within 3 months. We calculated test characteristics using standard methods. We also explored modifications of the age adjustment multiplier.We included 3837 patients and excluded 251. The mean age of patients evaluated for PE (n = 1834) was 48 ± 16 years, with 676 (37%) male, and 1081 (59%) white. The mean age of evaluated for DVT (n = 1752) was 53 ± 16 years, with 710 (41%) male, and 1172 (67%) white. D-dimer test characteristics for PE were: sensitivity 98.0%, specificity 55.4%, negative predictive value (NPV) 99.8%, positive predictive value (PPV) 11.4%, and for DVT were: sensitivity 92.0%, specificity 44.8%, NPV 98.8%, PPV 10.3%. Age adjustment increased specificity (59.6% [PE], 51.1% [DVT]), but increasing the age-adjustment multiplier decreased sensitivity without increasing specificity.INNOVANCE D-dimer is highly sensitive and can exclude PE and DVT in ED patients with low- and intermediate- pre-test probability. Age-adjustment increases specificity, without increasing false negatives.
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    Periodic Breathing and Behavioral Awakenings at High Altitude.
    (Sleep Disord, 2015) Shogilev, Daniel J; Tanner, John B; Chang, Yuchiao; Harris, N Stuart
    Objectives. To study the relationship between nocturnal periodic breathing episodes and behavioral awakenings at high altitude. Methods. Observational study. It is 6-day ascent of 4 healthy subjects from Besisahar (760 meters) to Manang (3540 meters) in Nepal in March 2012. A recording pulse oximeter was worn by each subject to measure their oxygen saturation and the presence of periodic breathing continuously through the night. An actigraph was simultaneously worn in order to determine nocturnal behavioral awakenings. There were no interventions. Results. 187-hour sleep at high altitude was analyzed, and of this, 145 hours (78%) had at least one PB event. At high altitude, 10.5% (95% CI 6.5-14.6%) of total sleep time was spent in PB while 15 out of 50 awakenings (30%, 95% CI: 18-45%) occurring at high altitudes were associated with PB (P < 0.001). Conclusions. Our data reveals a higher than expected number of behavioral awakenings associated with PB compared to what would be expected by chance. This suggests that PB likely plays a role in behavioral awakenings at high altitude.