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Hydrodynamic Characteristics of Bovine Pericardial and Porcine Valves Using a Mock Circulatory System Mimicking the Aortic and Pulmonary Positions

Wed, 01 Apr 2026 00:00:00 GMT

Title: Hydrodynamic Characteristics of Bovine Pericardial and Porcine Valves Using a Mock Circulatory System Mimicking the Aortic and Pulmonary Positions Authors: Shin, Yu Rim; Lee, Seung-Hyun; Shim, Jae-Kwang; Kim, Yongwoo; Lee, Sak Abstract: Purpose: Aortic prostheses are used in pulmonary positions due to structural similarities between the pulmonary and aortic valves. However, there are no available studies that have comprehensively evaluated the mechanism of bioprosthetic aortic valves under pulmonary conditions. Materials and Methods: Using a mock circulatory system, we evaluated the hydrodynamic characteristics of bovine pericardial and porcine valves. Geometric orifice area, regurgitant and leakage volume, regurgitant fraction, peak pressure gradient, and forward flow volume were evaluated in different pulmonary pressure conditions (from 15/5 mm Hg to 75/35 mm Hg) and normal aortic pressure (110/80 mm Hg). Results: Bovine pericardial valves were associated with larger opening area (0.93 +/- 0.01 vs.1.70 +/- 0.01 for 23-mm valve; 0.99 +/- 0.01 vs.1.75 +/- 0.01 for 25-mm valve; 1.58 +/- 0.01 vs. 2.25 +/- 0.02 for 27-mm valve; all p<0.01) and forward flow volume (42.27 +/- 0.05 vs. 64.79 +/- 0.14 for 23-mm valve; 46.41 +/- 0.06 vs. 64.28 +/- 0.18 for 25-mm valve; 72.64 +/- 0.17 vs.73.25 +/- 0.07 for 27-mm valve; all p<0.01). Porcine valves were associated with incomplete opening, smaller opening area, and lower regurgitant fraction. Bovine pericardial valves demonstrated lower peak pressure gradients (15.75 +/- 0.14 vs. 12.57 +/- 0.47 for 23-mm valve; 14.85 +/- 0.05 vs. 12.87 +/- 0.28 for 25-mm valve; 15.72 +/- 0.32 vs. 7.91 +/- 0.03 for 27-mm valve). Conclusion: Bovine pericardial and porcine bioprosthetic valves has different hydrodynamic characteristics under various pulmonary pressure conditions.

Comparison of Dexmedetomidine Administration Strategy for Propofol-Based Pediatric Sedation for Magnetic Resonance Imaging: A Retrospective Study

Wed, 01 Apr 2026 00:00:00 GMT

Title: Comparison of Dexmedetomidine Administration Strategy for Propofol-Based Pediatric Sedation for Magnetic Resonance Imaging: A Retrospective Study Authors: Kim, Tae-Won; Ji, Sang-Hwan; Park, Jung-Bin; Kang, Pyoyoon; Jang, Young-Eun; Kim, Eun-Hee; Lee, Ji-Hyun; Kim, Hee-Soo; Kim, Jin-Tae; 강표윤 Abstract: Background Intravenous dexmedetomidine is a safe and effective adjunct in propofol-based sedation. Dexmedetomidine is typically administered as a loading dose, followed by continuous infusion or not. Whether the addition of a maintenance infusion of dexmedetomidine after a loading dose in propofol-based sedation for pediatric magnetic resonance imaging (MRI) can be beneficial in terms of propofol consumption or adverse events is not clear.Aims We aimed to study whether maintaining dexmedetomidine infusion after loading dose can help reduce propofol consumption and minimize airway and cardiovascular interventions during sedation.Methods We retrospectively reviewed 884 medical records of pediatric sedation for MRI using both propofol and dexmedetomidine, performed at a single tertiary hospital between May 2021 and January 2023. We compared patients who received dexmedetomidine loading + maintenance (group LM) and dexmedetomidine loading only (group L) as an adjunct to propofol-based sedation. The consumption of propofol and time to recovery were measured. We also compared the incidence of airway rescue maneuver and hypotension requiring intervention during sedation.Results Overall, 695 patients were included in the analysis (group LM, n = 351, group L, n = 344). The total sedation duration was similar between the two groups (52 vs. 50 min, p = 0.255). Group LM showed significantly less total propofol consumption (6.62 vs. 7.63 mg & centerdot;kg-1 & centerdot;h-1, p = 0.001). The incidence of airway rescue maneuver did not differ significantly between the two groups (0.9 vs. 1.5%, p = 0.501); however, the incidence of hypotension requiring intervention was lower in group LM than in group L (4.3 vs. 8.1%, p = 0.040). The recovery time did not differ significantly between the two groups (34 vs. 34 min, p = 0.932).Conclusion In propofol-based sedation for pediatric MRI, maintenance infusion of dexmedetomidine after a loading dose reduces total propofol consumption and hemodynamic instability requiring intervention without prolonging recovery time, compared with dexmedetomidine bolus without maintenance.

The Association Between Early Postoperative Temperature Trajectories and Severe Acute Kidney Injury After Valvular Heart Surgery: A Retrospective Cohort Study

Sun, 01 Mar 2026 00:00:00 GMT

Title: The Association Between Early Postoperative Temperature Trajectories and Severe Acute Kidney Injury After Valvular Heart Surgery: A Retrospective Cohort Study Authors: Cho, Jin Sun; Suh, Sungmin; Shim, Jae-Kwang; Lee, Hye Sun; Choi, Hee Won; Yang, Hyejin; Kwak, Young-Lan Abstract: Background/Objectives: Postoperative body temperature abnormalities are common yet underrecognized, and their association with acute kidney injury (AKI) remains unclear. In this study, we aimed to identify early postoperative temperature trajectories and evaluate their associations with AKI. Methods: This retrospective cohort study included 3274 adults undergoing valvular heart surgery with cardiopulmonary bypass. The patients' temperatures were continuously measured using a pulmonary artery catheter for 12 postoperative hours, and temperature trajectories were identified using data-driven latrend class modeling. The primary outcome was severe AKI (KDIGO stage >= 2), and the secondary outcome was non-recovery AKI (>= 72 h). Multivariable logistic regression and E-value sensitivity analysis were performed. Results: Four distinct temperature trajectories were identified: Class 1 (32.8%), initial normothermia progressing to mild hyperthermia (37.5-38.0 degrees C); Class 2 (27.4%), mild hypothermia (36.0-36.5 degrees C) with rapid normalization; Class 3 (24.4%), stable normothermia; and Class 4 (15.4%), lower-range mild hypothermia (35.5-36.0 degrees C) with delayed recovery. Severe AKI and non-recovery AKI occurred most frequently in Class 4 patients (15.1% vs. 2.9%, 3.9%, and 4.8% in Classes 1-3, p < 0.001; 15.1% vs. 1.7%, 4.0%, and 4.4%, p < 0.001, respectively). After adjusting for key clinical variables, Class 4 remained independently associated with severe AKI (OR 2.44, 95% CI: 1.69-3.57; E-value 4.33) and non-recovery AKI (OR 2.78, 95% CI: 1.89-4.00; E-value 4.97). Conclusions: Early postoperative temperature trajectories were significantly associated with severe AKI, with the highest risks in patients exhibiting lower-range mild hypothermia with delayed recovery. These findings suggest that early postoperative temperature patterns may be useful for risk stratification for severe AKI after cardiac surgery.

Monitoring sympathectomy in regional anesthesia: pulse wave transit time variability after interscalene block

Sun, 01 Feb 2026 00:00:00 GMT

Title: Monitoring sympathectomy in regional anesthesia: pulse wave transit time variability after interscalene block Authors: Song, Jong Wook