Impact of wall thickness on the tissue cooling effect of cryoballoon ablation.

AIMS: Understanding of the tissue cooling properties of cryoballoon ablation during pulmonary vein (PV) isolation is lacking. The purpose of this study was to delineate the depth of the tissue cooling effect during cryoballoon freezing at the pulmonary venous ostium. METHODS AND RESULTS: A left atrial-PV model was constructed using a three-dimensional printer with data from a patient to which porcine thigh muscle of various thicknesses could be affixed. The model was placed in a 37°C water tank with a PV water flow at a rate that mimicked biological blood flow. Cryofreezing at the PV ostium was performed five times each for sliced porcine thigh muscle of 2, 4, and 6 mm thickness, and sliced muscle cooling on the side opposite the balloon was monitored. The cooling effect was assessed using the average temperature of 12 evenly distributed thermocouples covering the roof region of the left superior PV. Tissue cooling effects were in the order of the 2, 4, and 6 mm thicknesses, with an average temperature of -41.4 ± 4.2°C for 2 mm, -33.0 ± 4.0°C for 4 mm, and 8.0 ± 8.7°C for 6 mm at 180 s (P for trend <0.0001). In addition, tissue temperature drops were steeper in thin muscle (maximum temperature drop per 5 s: 5.2 ± 0.9°C, 3.9 ± 0.7°C, and 1.3 ± 0.7°C, P for trend <0.0001). CONCLUSION: The cooling effect of cryoballoon freezing is weaker in the deeper layers. Cryoballoon ablation should be performed with consideration to myocardial thickness.

Correlation between the Bayley-III at 3 years and the Wechsler Intelligence Scale for Children, Fourth Edition, at 6 years.

BACKGROUND: Although several studies have investigated the association between Bayley-III results in infancy and future intellectual development, conclusions remain unclear. We used the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) at 3 years of age and the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) at 6 years of age to assess the neurodevelopment of very low birthweight infants. METHODS: We investigated the correlation between Bayley-III's cognitive, language, and motor scores and the WISC-IV's Full-Scale Intelligence Quotient (FSIQ). We also determined the optimal cut-off value of Bayley-III to enter the normal development zone (FSIQ ≥ 85). RESULTS: We found a strong correlation between the Bayley-III and the FSIQ. Optimal cut-off scores of the Bayley-III to enter the normal range on the WISC-IV were 95 for the cognitive scale, 89 for the language scale, and 91 for the motor development scale. CONCLUSIONS: Although Bayley-III scores strongly correlated with the WISC-IV FSIQ, the lower normal limit of 85 on the Bayley-III suggests a potential overestimation of development in children who were VLBW infants.

Early ambulation after general and digestive surgery: a retrospective single-center study.

PURPOSE: Postoperative early ambulation contributes to the improvement of postoperative outcomes; however, the definition of "early" ambulation is unclear. In this study, we aimed to define desirable "early" ambulation after digestive surgery in terms of short-term outcomes and to identify the risk factors for delayed ambulation. METHODS: We retrospectively analyzed 718 patients who underwent major digestive surgery between January 2016 and May 2019 in our hospital. The timing of first ambulation after surgery was reviewed and correlated with short-term postoperative outcomes and perioperative patient characteristics. RESULTS: Of 718 patients, 55% underwent first ambulation at postoperative day (POD) 1, 31% at POD 2, and the remaining patients at POD 3 or later. Whereas short-term outcomes were equivalent among patients with first ambulation at POD 1 and those at POD 2, patients who delayed ambulation until POD 3 or after had an increased incidence of infectious complications (P = 0.004), longer hospitalization (P < 0.001), and a decreased home discharge rate (P < 0.001). Multivariate analysis showed that significant predictors of delayed ambulation (POD ≥ 3) were poor Eastern Cooperative Oncology Group performance status (ECOG-PS), low controlling nutritional status (CONUT), nonlaparoscopic surgery, and transvenous opioid use. Of these factors, the combination of ECOG-PS, CONUT, and nonlaparoscopic surgery clearly stratified patients into four-grade risk groups regarding delayed ambulation (P for trend < 0.001). CONCLUSION: Our results suggest that first ambulation before POD 2 could be desirable for better short-term outcomes. Active preoperative intervention, such as nutritional care and prehabilitation, in patients with multiple risk factors for delayed ambulation could improve the postoperative course.