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    Early Oxidative Stress Response in Patients with Severe Aortic Stenosis Undergoing Transcatheter and Surgical Aortic Valve Replacement: A Transatlantic Study
    (2019)
    Michael Mahmoudi
    ;
    Juan Guillermo Gormaz
    ;
    Marcia Erazo
    ;
    Michael Howard
    ;
    Cristian Baeza
    Myocardial ischemia/reperfusion-related oxidative stress as a result of cardiopulmonary bypass is thought to contribute to the adverse clinical outcomes following surgical aortic valve replacement (SAVR). Although the acute response following this procedure has been well characterized, much less is known about the nature and extent of oxidative stress induced by the transcatheter aortic valve replacement (TAVR) procedure. We therefore sought to examine and directly compare the oxidative stress response in patients undergoing TAVR and SAVR. A total of 60 patients were prospectively enrolled in this exploratory study, 38 patients undergoing TAVR and 22 patients SAVR. Reduced and oxidized glutathione (GSH, GSSG) in red blood cells as well as the ferric-reducing ability of plasma (FRAP) and plasma concentrations of 8-isoprostanes were measured at baseline (S1), during early reperfusion (S2), and 6-8 hours (S3) following aortic valve replacement (AVR). TAVR and SAVR were successful in all patients. Patients undergoing TAVR were older (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mn>79.3</mml:mn><mml:mo>±</mml:mo><mml:mn>9.5</mml:mn></mml:math> vs. <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mn>74.2</mml:mn><mml:mo>±</mml:mo><mml:mn>4.1</mml:mn></mml:math> years; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mi>P</mml:mi><mml:mo>&lt;</mml:mo><mml:mn>0.01</mml:mn></mml:math>) and had a higher mean STS risk score (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mn>6.6</mml:mn><mml:mo>±</mml:mo><mml:mn>4.8</mml:mn></mml:math> vs. <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M5"><mml:mn>3.2</mml:mn><mml:mo>±</mml:mo><mml:mn>3.0</mml:mn></mml:math>; <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M6"><mml:mi>P</mml:mi><mml:mo>&lt;</mml:mo><mml:mn>0.001</mml:mn></mml:math>) than patients undergoing SAVR. At baseline, FRAP and 8-isoprostane plasma concentrations were similar between the two groups, but erythrocytic GSH concentrations were significantly lower in the TAVR group. After AVR, FRAP was markedly higher in the TAVR group, whereas 8-isoprostane concentrations were significantly elevated in the SAVR group. In conclusion, TAVR appears not to cause acute oxidative stress and may even improve the antioxidant capacity in the extracellular compartment.
    Scopus© Citations 4  4
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    Scopus© Citations 64  5
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    Continuous prolonged prone positioning in COVID-19-related ARDS: a multicenter cohort study from Chile
    (2022)
    Rodrigo A. Cornejo
    ;
    Jorge Montoya
    ;
    Abraham I. J. Gajardo
    ;
    ;
    Leyla Alegría
    <jats:title>Abstract</jats:title><jats:sec> <jats:title>Background</jats:title> <jats:p>Prone positioning is currently applied in time-limited daily sessions up to 24 h which determines that most patients require several sessions. Although longer prone sessions have been reported, there is scarce evidence about the feasibility and safety of such approach. We analyzed feasibility and safety of a continuous prolonged prone positioning strategy implemented nationwide, in a large cohort of COVID-19 patients in Chile.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>Retrospective cohort study of mechanically ventilated COVID-19 patients with moderate-to-severe acute respiratory distress syndrome (ARDS), conducted in 15 Intensive Care Units, which adhered to a national protocol of continuous prone sessions  ≥ 48 h and until PaO<jats:sub>2</jats:sub>:FiO<jats:sub>2</jats:sub> increased above 200 mm Hg. The number and extension of prone sessions were registered, along with relevant physiologic data and adverse events related to prone positioning. The cohort was stratified according to the first prone session duration: Group A, 2–3 days; Group B, 4–5 days; and Group C, &gt; 5 days. Multivariable regression analyses were performed to assess whether the duration of prone sessions could impact safety.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>We included 417 patients who required a first prone session of 4 (3–5) days, of whom 318 (76.3%) received only one session. During the first prone session the main adverse event was grade 1–2 pressure sores in 97 (23.9%) patients; severe adverse events were infrequent with 17 non-scheduled extubations (4.2%). 90-day mortality was 36.2%. Ninety-eight patients (24%) were classified as group C; they exhibited a more severe ARDS at baseline, as reflected by lower PaO<jats:sub>2</jats:sub>:FiO<jats:sub>2</jats:sub> ratio and higher ventilatory ratio, and had a higher rate of pressure sores (44%) and higher 90-day mortality (48%). However, after adjustment for severity and several relevant confounders, prone session duration was not associated with mortality or pressure sores.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Nationwide implementation of a continuous prolonged prone positioning strategy for COVID-19 ARDS patients was feasible. Minor pressure sores were frequent but within the ranges previously described, while severe adverse events were infrequent. The duration of prone session did not have an adverse effect on safety.</jats:p> </jats:sec>
    Scopus© Citations 17  1