1.Novel non-invasive and quantitative assessment of the renal function of transplanted kidneys using Doppler ultrasonography with the vascular index of superb microvascular imaging
Sung Hwan BAE ; Eun Ji LEE ; Jiyoung HWANG ; Seong Sook HONG ; Yun-Woo CHANG ; Boda NAM
Ultrasonography 2025;44(2):160-169
Purpose:
This study assessed the reproducibility and clinical value of the vascular index (VI), derived from superb microvascular imaging (SMI) using Doppler ultrasonography, for evaluating renal function in transplanted kidneys.
Methods:
This retrospective study included 63 renal transplant patients who underwent grayscale and Doppler ultrasonography with SMI from January 2022 to February 2023. The VI of the transplanted kidneys was measured using three methods (VIbox, VIF1, VIF2). The VI was compared across chronic kidney disease (CKD) groups categorized by estimated glomerular filtration rate (eGFR) and Kidney Disease: Improving Global Outcomes (KDIGO) CKD risk groups based on eGFR and albuminuria. The correlation between VI and renal function was evaluated. Univariate and multivariate linear regression analyses were used to identify predictors of eGFR.
Results:
Significant differences in VI were observed among CKD groups based on eGFR (VIbox, P=0.001; VIF1, P<0.001; VIF2, P<0.001) and KDIGO CKD groups based on eGFR and albuminuria (VIbox, P=0.039; VIF1, P=0.001; VIF2, P<0.001). VIF1 and VIF2 demonstrated moderate/high correlations with eGFR (r=0.627, P<0.001 and r=0.657, P<0.001, respectively) and serum creatinine (r=-0.626, P<0.001 and r=-0.649, P<0.001, respectively). VIbox moderately correlated with eGFR (r=0.445, P<0.001). Multivariate regression identified the urine albumincreatinine ratio (ACR) (adjusted odds ratio [aOR], 1.122; 95% confidence interval [CI], -0.007 to, 0.000; P=0.030) and VIF2 (aOR, 1.114; 95% CI, 0.466 to 1.235; P<0.001) were independently associated with eGFR.
Conclusion
The VI measured by drawing a region of interest along the border of the transplanted kidney in SMI (VIF2) is highly reproducible and correlates well with eGFR. Both VIF2 and ACR independently predict eGFR.
2.Elevated Soluble Suppressor of Tumorigenicity 2Levels in Gout Patients and Its Association with Cardiovascular Disease Risk Indicators
Jiyoung Agatha KIM ; Ji Eun LEE ; Kunhyung BAE ; Sung Soo AHN
Yonsei Medical Journal 2025;66(3):151-159
Purpose:
To investigate the association between soluble suppressor of tumorigenicity 2 (sST2) levels and cardiovascular disease predictors in patients with gout.
Materials and Methods:
We retrospectively reviewed the medical records of patients with gout who were tested for sST2 but did not receive uric acid-lowering therapy. These patients were classified into elevated and normal sST2 groups using a cut-off of >49.6 ng/mL and >35.4 ng/mL in males and females, respectively. Correlations between clinical and laboratory variables, sST2 levels, and elevated sST2 level predictors were assessed using linear and logistic regression analyses.
Results:
Notably, 27 (11.3%) and 211 (88.7%) of the 238 identified patients had elevated and normal sST2 levels, respectively. Linear regression analysis revealed that male sex (β=-0.190, p=0.002), body mass index (BMI) (β=-0.184, p=0.002), white blood cell count (β=0.231, p<0.001), C-reactive protein (β=0.135, p=0.031), and fasting blood glucose (β=0.210, p<0.001) were independently associated with sST2 levels. In multivariate logistic regression analysis, male sex [odds ratio (OR) 0.112, p=0.001], BMI (OR 0.836, p=0.008), creatinine (OR 5.730, p=0.024), and fasting blood glucose (OR 1.042, p=0.002) predicted elevated sST2 levels. Patients with increased sST2 levels had a significantly higher atherosclerotic cardiovascular disease risk score and a greater proportion of high-risk Framingham Risk Score compared to the normal sST2 group (p=0.002 and p<0.001).
Conclusion
Patients with gout and elevated sST2 levels have a higher risk of future cardiovascular disorders, which may provide insights into risk stratification and the implementation of intervention strategies.
3.Novel non-invasive and quantitative assessment of the renal function of transplanted kidneys using Doppler ultrasonography with the vascular index of superb microvascular imaging
Sung Hwan BAE ; Eun Ji LEE ; Jiyoung HWANG ; Seong Sook HONG ; Yun-Woo CHANG ; Boda NAM
Ultrasonography 2025;44(2):160-169
Purpose:
This study assessed the reproducibility and clinical value of the vascular index (VI), derived from superb microvascular imaging (SMI) using Doppler ultrasonography, for evaluating renal function in transplanted kidneys.
Methods:
This retrospective study included 63 renal transplant patients who underwent grayscale and Doppler ultrasonography with SMI from January 2022 to February 2023. The VI of the transplanted kidneys was measured using three methods (VIbox, VIF1, VIF2). The VI was compared across chronic kidney disease (CKD) groups categorized by estimated glomerular filtration rate (eGFR) and Kidney Disease: Improving Global Outcomes (KDIGO) CKD risk groups based on eGFR and albuminuria. The correlation between VI and renal function was evaluated. Univariate and multivariate linear regression analyses were used to identify predictors of eGFR.
Results:
Significant differences in VI were observed among CKD groups based on eGFR (VIbox, P=0.001; VIF1, P<0.001; VIF2, P<0.001) and KDIGO CKD groups based on eGFR and albuminuria (VIbox, P=0.039; VIF1, P=0.001; VIF2, P<0.001). VIF1 and VIF2 demonstrated moderate/high correlations with eGFR (r=0.627, P<0.001 and r=0.657, P<0.001, respectively) and serum creatinine (r=-0.626, P<0.001 and r=-0.649, P<0.001, respectively). VIbox moderately correlated with eGFR (r=0.445, P<0.001). Multivariate regression identified the urine albumincreatinine ratio (ACR) (adjusted odds ratio [aOR], 1.122; 95% confidence interval [CI], -0.007 to, 0.000; P=0.030) and VIF2 (aOR, 1.114; 95% CI, 0.466 to 1.235; P<0.001) were independently associated with eGFR.
Conclusion
The VI measured by drawing a region of interest along the border of the transplanted kidney in SMI (VIF2) is highly reproducible and correlates well with eGFR. Both VIF2 and ACR independently predict eGFR.
4.Elevated Soluble Suppressor of Tumorigenicity 2Levels in Gout Patients and Its Association with Cardiovascular Disease Risk Indicators
Jiyoung Agatha KIM ; Ji Eun LEE ; Kunhyung BAE ; Sung Soo AHN
Yonsei Medical Journal 2025;66(3):151-159
Purpose:
To investigate the association between soluble suppressor of tumorigenicity 2 (sST2) levels and cardiovascular disease predictors in patients with gout.
Materials and Methods:
We retrospectively reviewed the medical records of patients with gout who were tested for sST2 but did not receive uric acid-lowering therapy. These patients were classified into elevated and normal sST2 groups using a cut-off of >49.6 ng/mL and >35.4 ng/mL in males and females, respectively. Correlations between clinical and laboratory variables, sST2 levels, and elevated sST2 level predictors were assessed using linear and logistic regression analyses.
Results:
Notably, 27 (11.3%) and 211 (88.7%) of the 238 identified patients had elevated and normal sST2 levels, respectively. Linear regression analysis revealed that male sex (β=-0.190, p=0.002), body mass index (BMI) (β=-0.184, p=0.002), white blood cell count (β=0.231, p<0.001), C-reactive protein (β=0.135, p=0.031), and fasting blood glucose (β=0.210, p<0.001) were independently associated with sST2 levels. In multivariate logistic regression analysis, male sex [odds ratio (OR) 0.112, p=0.001], BMI (OR 0.836, p=0.008), creatinine (OR 5.730, p=0.024), and fasting blood glucose (OR 1.042, p=0.002) predicted elevated sST2 levels. Patients with increased sST2 levels had a significantly higher atherosclerotic cardiovascular disease risk score and a greater proportion of high-risk Framingham Risk Score compared to the normal sST2 group (p=0.002 and p<0.001).
Conclusion
Patients with gout and elevated sST2 levels have a higher risk of future cardiovascular disorders, which may provide insights into risk stratification and the implementation of intervention strategies.
5.Obstructive Sleep Apnea as an Underrecognized Cause of Nocturnal Arrhythmia: A Case Report
Jae Wook CHO ; Gha-Hyun LEE ; Jiyoung KIM
Journal of Sleep Medicine 2025;22(1):35-38
Obstructive sleep apnea (OSA), characterized by nocturnal airway obstruction, hypoxia, and arousal, is a significant risk factor for cardiovascular diseases, including arrhythmia. This case report describes the association between OSA and nocturnal sinus tachycardia in a 58-year-old woman who presented with sleep maintenance difficulties and recurrent nocturnal tachycardia. Polysomnography confirmed a direct correlation among the apnea/hypopnea episodes, tachycardia, and sleep maintenance difficulties. Continuous positive airway pressure therapy effectively resolved tachycardia and sleep maintenance difficulties, reducing the number of medications required to alleviate the symptoms. This report highlights the importance of considering OSA as a possible cause of unexplained nocturnal tachycardia.
6.Standardized learner simulation for debriefer training through video conference
Korean Journal of Medical Education 2025;37(1):35-45
Purpose:
Debriefing after simulation-based healthcare education (SBHE) is challenging. Educators’ debriefing skills are essential to the success of learning. For debriefing skill training, we designed a simulation course with the standardized learner (SL) through video conference. The purpose of this study was to describe the implementation process of the SL simulation course and evaluate its effectiveness on educators’ self-confidence and debriefing skills.
Methods:
This simulation course involved six trainees and two trainers. After watching a 5-minute sample video of SBHE, each trainee conducted their role as a debriefer in this video and the trainer acted as a learner (SL) in this video. Following each simulation, individual feedback by the trainer was immediately implemented. To evaluate the course’s effectiveness, trainees’ self-confidence questionnaire was collected, and objective structured assessment of debriefing (OSAD) scores were evaluated.
Results:
After completing five SL simulation sessions in 2 weeks, the trainees’ self-confidence level and OSAD scores improved significantly (estimate=0.114, standard error=0.020, p<0.001, and p=0.006).
Conclusion
This debriefer training course using SL simulation via video conference could improve self-confidence and debriefing skills of trainees. This SL simulation can be used as a new and flexible method for training debriefers.
7.Nationwide big data analysis of inguinal hernia surgery trends in South Korea (2016–2022)
Hyunjeong KI ; Seyoung KOO ; Gil Ho KANG ; Jiyoung SUL ; Junbeom PARK
Annals of Surgical Treatment and Research 2025;108(4):211-218
Purpose:
This study aimed to analyze nationwide trends and regional disparities in inguinal hernia surgeries in South Korea between 2016 and 2022. Additionally, we aimed to evaluate changes in surgery frequency, including urban concentration and the introduction of robotic surgery.
Methods:
This retrospective review used nationwide data on inguinal hernia surgeries from the Health Insurance Review and Assessment Service database.
Results:
From 2016 to 2022, 254,367 inguinal hernia surgeries were performed in South Korea, with males accounting for 88.9% of cases. The annual number of surgeries fluctuated, particularly in 2020, owing to the coronavirus disease 2019 pandemic. Medical costs increased from $1,218.4 to $1,970 on average, whereas patient copayments rose from $180.2 to $293.3. Robotic inguinal hernia surgeries, introduced in 2019, increased to 226 cases in 2022. Pediatric surgeries steadily declined, whereas adult surgeries remained stable, with a slight increase in 2022. The average hospital stay did not change significantly but varied between pediatric and adult patients. Regional disparities were notable, especially in pediatric surgery rates between metropolitan areas, such as Seoul and the surrounding provinces.
Conclusion
This study highlights stable overall surgery rates, a decline in pediatric cases, and an increase in robotic inguinal hernia surgeries. The persistent concentration of healthcare services in metropolitan areas suggests a need for policy interventions to address regional disparities and ensure equitable healthcare access. The findings underscore the importance of ongoing efforts to improve healthcare distribution and the need for long-term strategies to address changing surgical trends.
8.Outcomes of pancreas transplantation over two decades:a single-center retrospective cohort study
Jiyoung SHIN ; Hye Young WOO ; Eun-Ah JO ; Ara CHO ; Ahram HAN ; Sanghyun AHN ; Sangil MIN ; Jongwon HA
Annals of Surgical Treatment and Research 2025;108(5):271-278
Purpose:
Pancreas transplantation (PT) is a definitive treatment for diabetes mellitus (DM), restoring endogenous insulin secretion and improving glycemic control. Despite its efficacy, PT is less common in South Korea compared to Western nations. This study aims to report the clinical outcomes of PT over 2 decades at a single center, focusing on surgical techniques, complications, and graft survival.
Methods:
A retrospective analysis of 69 PT recipients at Seoul National University Hospital between January 2002 and December 2023 was conducted. Data on recipient and donor demographics, surgical details, immunosuppressive regimens, and graft outcomes were collected. Graft survival was evaluated using Kaplan-Meier analysis, with subgroup comparisons using the log-rank test. Graft failure was defined as graft removal, PT re-registration, insulin dependence exceeding 0.5 units/kg/day for more than 90 days, or patient death.
Results:
Among the 69 recipients, 50 (72.5%) had type 1 DM, and 18 (26.1%) had type 2 DM. Simultaneous pancreaskidney (SPK) transplantations comprised 84.1% (n = 58), and pancreas-after-kidney (PAK) transplantations accounted for 10.1%. The 1-year and 5-year death-censored pancreas graft survival rates were 92.7% and 89.6%, respectively, with no significant difference between SPK and PAK (P = 0.330). Graft failure occurred in 10 patients, primarily due to pancreatitis and rejection. Donor-related factors, particularly anoxic brain injury, were significantly associated with lower graft survival (P = 0.045).
Conclusion
PT outcomes in this cohort align with international standards, emphasizing the importance of donor selection and tailored immunosuppression. Expanding PT indications to include selective type 2 DM patients could benefit South Korea’s PT programs with adequate resource allocation.
9.Novel non-invasive and quantitative assessment of the renal function of transplanted kidneys using Doppler ultrasonography with the vascular index of superb microvascular imaging
Sung Hwan BAE ; Eun Ji LEE ; Jiyoung HWANG ; Seong Sook HONG ; Yun-Woo CHANG ; Boda NAM
Ultrasonography 2025;44(2):160-169
Purpose:
This study assessed the reproducibility and clinical value of the vascular index (VI), derived from superb microvascular imaging (SMI) using Doppler ultrasonography, for evaluating renal function in transplanted kidneys.
Methods:
This retrospective study included 63 renal transplant patients who underwent grayscale and Doppler ultrasonography with SMI from January 2022 to February 2023. The VI of the transplanted kidneys was measured using three methods (VIbox, VIF1, VIF2). The VI was compared across chronic kidney disease (CKD) groups categorized by estimated glomerular filtration rate (eGFR) and Kidney Disease: Improving Global Outcomes (KDIGO) CKD risk groups based on eGFR and albuminuria. The correlation between VI and renal function was evaluated. Univariate and multivariate linear regression analyses were used to identify predictors of eGFR.
Results:
Significant differences in VI were observed among CKD groups based on eGFR (VIbox, P=0.001; VIF1, P<0.001; VIF2, P<0.001) and KDIGO CKD groups based on eGFR and albuminuria (VIbox, P=0.039; VIF1, P=0.001; VIF2, P<0.001). VIF1 and VIF2 demonstrated moderate/high correlations with eGFR (r=0.627, P<0.001 and r=0.657, P<0.001, respectively) and serum creatinine (r=-0.626, P<0.001 and r=-0.649, P<0.001, respectively). VIbox moderately correlated with eGFR (r=0.445, P<0.001). Multivariate regression identified the urine albumincreatinine ratio (ACR) (adjusted odds ratio [aOR], 1.122; 95% confidence interval [CI], -0.007 to, 0.000; P=0.030) and VIF2 (aOR, 1.114; 95% CI, 0.466 to 1.235; P<0.001) were independently associated with eGFR.
Conclusion
The VI measured by drawing a region of interest along the border of the transplanted kidney in SMI (VIF2) is highly reproducible and correlates well with eGFR. Both VIF2 and ACR independently predict eGFR.
10.Novel non-invasive and quantitative assessment of the renal function of transplanted kidneys using Doppler ultrasonography with the vascular index of superb microvascular imaging
Sung Hwan BAE ; Eun Ji LEE ; Jiyoung HWANG ; Seong Sook HONG ; Yun-Woo CHANG ; Boda NAM
Ultrasonography 2025;44(2):160-169
Purpose:
This study assessed the reproducibility and clinical value of the vascular index (VI), derived from superb microvascular imaging (SMI) using Doppler ultrasonography, for evaluating renal function in transplanted kidneys.
Methods:
This retrospective study included 63 renal transplant patients who underwent grayscale and Doppler ultrasonography with SMI from January 2022 to February 2023. The VI of the transplanted kidneys was measured using three methods (VIbox, VIF1, VIF2). The VI was compared across chronic kidney disease (CKD) groups categorized by estimated glomerular filtration rate (eGFR) and Kidney Disease: Improving Global Outcomes (KDIGO) CKD risk groups based on eGFR and albuminuria. The correlation between VI and renal function was evaluated. Univariate and multivariate linear regression analyses were used to identify predictors of eGFR.
Results:
Significant differences in VI were observed among CKD groups based on eGFR (VIbox, P=0.001; VIF1, P<0.001; VIF2, P<0.001) and KDIGO CKD groups based on eGFR and albuminuria (VIbox, P=0.039; VIF1, P=0.001; VIF2, P<0.001). VIF1 and VIF2 demonstrated moderate/high correlations with eGFR (r=0.627, P<0.001 and r=0.657, P<0.001, respectively) and serum creatinine (r=-0.626, P<0.001 and r=-0.649, P<0.001, respectively). VIbox moderately correlated with eGFR (r=0.445, P<0.001). Multivariate regression identified the urine albumincreatinine ratio (ACR) (adjusted odds ratio [aOR], 1.122; 95% confidence interval [CI], -0.007 to, 0.000; P=0.030) and VIF2 (aOR, 1.114; 95% CI, 0.466 to 1.235; P<0.001) were independently associated with eGFR.
Conclusion
The VI measured by drawing a region of interest along the border of the transplanted kidney in SMI (VIF2) is highly reproducible and correlates well with eGFR. Both VIF2 and ACR independently predict eGFR.

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