Background and Objectives: Angiographic assessment of coronary stenosis severity using quantitative coronary angiography (QCA) is often inconsistent with that based on fractional flow reserve (FFR) or intravascular ultrasound (IVUS). We investigated the incidence of discrepancies between QCA and FFR or IVUS, and the outcomes of FFR- and IVUS-guided strategies in discordant coronary lesions. Methods: This study was a post-hoc analysis of the FLAVOUR study. We used a QCA-derived diameter stenosis (DS) of 60% or greater, the highest tertile, to classify coronary lesions as concordant or discordant with FFR or IVUS criteria for percutaneous coronary intervention (PCI). The patient-oriented composite outcome (POCO) was defined as a composite of death, myocardial infarction, or revascularization at 24 months. Results: The discordance rate between QCA and FFR or IVUS was 30.2% (n=551). The QCAFFR discordance rate was numerically lower than the QCA-IVUS discordance rate (28.2% vs. 32.4%, p=0.050). In 200 patients with ≥60% DS, PCI was deferred according to negative FFR (n=141) and negative IVUS (n=59) (15.3% vs. 6.5%, p<0.001). The POCO incidence was comparable between the FFR- and IVUS-guided deferral strategies (5.9% vs. 3.4%, p=0.479).Conversely, 351 patients with DS <60% underwent PCI according to positive FFR (n=118) and positive IVUS (n=233) (12.8% vs. 25.9%, p<0.001). FFR- and IVUS-guided PCI did not differ in the incidence of POCO (9.5% vs. 6.5%, p=0.294). Conclusions The proportion of QCA-FFR or IVUS discordance was approximately one third for intermediate coronary lesions. FFR- or IVUS-guided strategies for these lesions were comparable with respect to POCO at 24 months.

Background and Objectives: Angiographic assessment of coronary stenosis severity using quantitative coronary angiography (QCA) is often inconsistent with that based on fractional flow reserve (FFR) or intravascular ultrasound (IVUS). We investigated the incidence of discrepancies between QCA and FFR or IVUS, and the outcomes of FFR- and IVUS-guided strategies in discordant coronary lesions. Methods: This study was a post-hoc analysis of the FLAVOUR study. We used a QCA-derived diameter stenosis (DS) of 60% or greater, the highest tertile, to classify coronary lesions as concordant or discordant with FFR or IVUS criteria for percutaneous coronary intervention (PCI). The patient-oriented composite outcome (POCO) was defined as a composite of death, myocardial infarction, or revascularization at 24 months. Results: The discordance rate between QCA and FFR or IVUS was 30.2% (n=551). The QCAFFR discordance rate was numerically lower than the QCA-IVUS discordance rate (28.2% vs. 32.4%, p=0.050). In 200 patients with ≥60% DS, PCI was deferred according to negative FFR (n=141) and negative IVUS (n=59) (15.3% vs. 6.5%, p<0.001). The POCO incidence was comparable between the FFR- and IVUS-guided deferral strategies (5.9% vs. 3.4%, p=0.479).Conversely, 351 patients with DS <60% underwent PCI according to positive FFR (n=118) and positive IVUS (n=233) (12.8% vs. 25.9%, p<0.001). FFR- and IVUS-guided PCI did not differ in the incidence of POCO (9.5% vs. 6.5%, p=0.294). Conclusions The proportion of QCA-FFR or IVUS discordance was approximately one third for intermediate coronary lesions. FFR- or IVUS-guided strategies for these lesions were comparable with respect to POCO at 24 months.

Objective: There has been a rapid increase in the utilization of emergency departments (EDs), especially for non-emergent cases. The challenges of accessing medical services at night cause disparities in ED utilization between the day and night. Additionally, the coronavirus disease-2019 (COVID-19) pandemic has had a notable impact on ED visits. This study aimed to compare the characteristics of patients visiting the EDs in the daytime and at night before and after COVID-19. Methods: A retrospective observational study was conducted on adults (≥18 years) at three metropolitan EDs from January 1, 2019 to December 31, 2020. Data, including the Korean Triage Acuity System, Tenth Revision (ICD-10) codes, and ICU admissions, were collected. Characteristics of patients visiting the ED during the day (06:00-18:00) and night (18:00-06:00) periods before and after COVID-19 were analyzed. Results: During the pre-COVID-19 and COVID-19 periods, 117,896 and 92,915 patients visited the ED, respectively. Non-emergency nighttime visits were increased than daytime visits during both the pre-COVID-19 period (37.9% vs. 30.9%) and the COVID-19 period (35.4% vs. 28.8%) (P<0.01). During COVID-19, non-emergency patient visits to the ED during the nighttime decreased compared to those during the day (odds ratio, 0.96; 95% confidence interval [CI], 0.93-0.99, P=0.01). Among the top five diagnoses, the number of patients declined during the COVID-19 pandemic in most categories, except for the category of “Fever of other and unknown origin,” which saw an increase both during the day (incident rate ratio [IRR], 1.10; 95% CI, 1.05-1.17) and night (IRR, 1.23; 95% CI, 1.17-1.30). Conclusion The COVID-19 pandemic significantly influenced ED visit patterns, particularly by reducing non-emergent visits during nighttime.

Objective: There has been a rapid increase in the utilization of emergency departments (EDs), especially for non-emergent cases. The challenges of accessing medical services at night cause disparities in ED utilization between the day and night. Additionally, the coronavirus disease-2019 (COVID-19) pandemic has had a notable impact on ED visits. This study aimed to compare the characteristics of patients visiting the EDs in the daytime and at night before and after COVID-19. Methods: A retrospective observational study was conducted on adults (≥18 years) at three metropolitan EDs from January 1, 2019 to December 31, 2020. Data, including the Korean Triage Acuity System, Tenth Revision (ICD-10) codes, and ICU admissions, were collected. Characteristics of patients visiting the ED during the day (06:00-18:00) and night (18:00-06:00) periods before and after COVID-19 were analyzed. Results: During the pre-COVID-19 and COVID-19 periods, 117,896 and 92,915 patients visited the ED, respectively. Non-emergency nighttime visits were increased than daytime visits during both the pre-COVID-19 period (37.9% vs. 30.9%) and the COVID-19 period (35.4% vs. 28.8%) (P<0.01). During COVID-19, non-emergency patient visits to the ED during the nighttime decreased compared to those during the day (odds ratio, 0.96; 95% confidence interval [CI], 0.93-0.99, P=0.01). Among the top five diagnoses, the number of patients declined during the COVID-19 pandemic in most categories, except for the category of “Fever of other and unknown origin,” which saw an increase both during the day (incident rate ratio [IRR], 1.10; 95% CI, 1.05-1.17) and night (IRR, 1.23; 95% CI, 1.17-1.30). Conclusion The COVID-19 pandemic significantly influenced ED visit patterns, particularly by reducing non-emergent visits during nighttime.

Background and Objectives: Angiographic assessment of coronary stenosis severity using quantitative coronary angiography (QCA) is often inconsistent with that based on fractional flow reserve (FFR) or intravascular ultrasound (IVUS). We investigated the incidence of discrepancies between QCA and FFR or IVUS, and the outcomes of FFR- and IVUS-guided strategies in discordant coronary lesions. Methods: This study was a post-hoc analysis of the FLAVOUR study. We used a QCA-derived diameter stenosis (DS) of 60% or greater, the highest tertile, to classify coronary lesions as concordant or discordant with FFR or IVUS criteria for percutaneous coronary intervention (PCI). The patient-oriented composite outcome (POCO) was defined as a composite of death, myocardial infarction, or revascularization at 24 months. Results: The discordance rate between QCA and FFR or IVUS was 30.2% (n=551). The QCAFFR discordance rate was numerically lower than the QCA-IVUS discordance rate (28.2% vs. 32.4%, p=0.050). In 200 patients with ≥60% DS, PCI was deferred according to negative FFR (n=141) and negative IVUS (n=59) (15.3% vs. 6.5%, p<0.001). The POCO incidence was comparable between the FFR- and IVUS-guided deferral strategies (5.9% vs. 3.4%, p=0.479).Conversely, 351 patients with DS <60% underwent PCI according to positive FFR (n=118) and positive IVUS (n=233) (12.8% vs. 25.9%, p<0.001). FFR- and IVUS-guided PCI did not differ in the incidence of POCO (9.5% vs. 6.5%, p=0.294). Conclusions The proportion of QCA-FFR or IVUS discordance was approximately one third for intermediate coronary lesions. FFR- or IVUS-guided strategies for these lesions were comparable with respect to POCO at 24 months.

Objective: There has been a rapid increase in the utilization of emergency departments (EDs), especially for non-emergent cases. The challenges of accessing medical services at night cause disparities in ED utilization between the day and night. Additionally, the coronavirus disease-2019 (COVID-19) pandemic has had a notable impact on ED visits. This study aimed to compare the characteristics of patients visiting the EDs in the daytime and at night before and after COVID-19. Methods: A retrospective observational study was conducted on adults (≥18 years) at three metropolitan EDs from January 1, 2019 to December 31, 2020. Data, including the Korean Triage Acuity System, Tenth Revision (ICD-10) codes, and ICU admissions, were collected. Characteristics of patients visiting the ED during the day (06:00-18:00) and night (18:00-06:00) periods before and after COVID-19 were analyzed. Results: During the pre-COVID-19 and COVID-19 periods, 117,896 and 92,915 patients visited the ED, respectively. Non-emergency nighttime visits were increased than daytime visits during both the pre-COVID-19 period (37.9% vs. 30.9%) and the COVID-19 period (35.4% vs. 28.8%) (P<0.01). During COVID-19, non-emergency patient visits to the ED during the nighttime decreased compared to those during the day (odds ratio, 0.96; 95% confidence interval [CI], 0.93-0.99, P=0.01). Among the top five diagnoses, the number of patients declined during the COVID-19 pandemic in most categories, except for the category of “Fever of other and unknown origin,” which saw an increase both during the day (incident rate ratio [IRR], 1.10; 95% CI, 1.05-1.17) and night (IRR, 1.23; 95% CI, 1.17-1.30). Conclusion The COVID-19 pandemic significantly influenced ED visit patterns, particularly by reducing non-emergent visits during nighttime.

Background and Objectives: Angiographic assessment of coronary stenosis severity using quantitative coronary angiography (QCA) is often inconsistent with that based on fractional flow reserve (FFR) or intravascular ultrasound (IVUS). We investigated the incidence of discrepancies between QCA and FFR or IVUS, and the outcomes of FFR- and IVUS-guided strategies in discordant coronary lesions. Methods: This study was a post-hoc analysis of the FLAVOUR study. We used a QCA-derived diameter stenosis (DS) of 60% or greater, the highest tertile, to classify coronary lesions as concordant or discordant with FFR or IVUS criteria for percutaneous coronary intervention (PCI). The patient-oriented composite outcome (POCO) was defined as a composite of death, myocardial infarction, or revascularization at 24 months. Results: The discordance rate between QCA and FFR or IVUS was 30.2% (n=551). The QCAFFR discordance rate was numerically lower than the QCA-IVUS discordance rate (28.2% vs. 32.4%, p=0.050). In 200 patients with ≥60% DS, PCI was deferred according to negative FFR (n=141) and negative IVUS (n=59) (15.3% vs. 6.5%, p<0.001). The POCO incidence was comparable between the FFR- and IVUS-guided deferral strategies (5.9% vs. 3.4%, p=0.479).Conversely, 351 patients with DS <60% underwent PCI according to positive FFR (n=118) and positive IVUS (n=233) (12.8% vs. 25.9%, p<0.001). FFR- and IVUS-guided PCI did not differ in the incidence of POCO (9.5% vs. 6.5%, p=0.294). Conclusions The proportion of QCA-FFR or IVUS discordance was approximately one third for intermediate coronary lesions. FFR- or IVUS-guided strategies for these lesions were comparable with respect to POCO at 24 months.

Viral load and the duration of viral shedding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are important determinants of the transmission of coronavirus disease 2019.In this study, we examined the effects of viral doses on the lung and spleen of K18-hACE2 transgenic mice by temporal histological and transcriptional analyses. Approximately, 1×105 plaque-forming units (PFU) of SARS-CoV-2 induced strong host responses in the lungs from 2 days post inoculation (dpi) which did not recover until the mice died, whereas responses to the virus were obvious at 5 days, recovering to the basal state by 14 dpi at 1×102 PFU. Further, flow cytometry showed that number of CD8+ T cells continuously increased in 1×102 PFU-virusinfected lungs from 2 dpi, but not in 1×105 PFU-virus-infected lungs. In spleens, responses to the virus were prominent from 2 dpi, and number of B cells was significantly decreased at 1×105PFU; however, 1×102 PFU of virus induced very weak responses from 2 dpi which recovered by 10 dpi. Although the defense responses returned to normal and the mice survived, lung histology showed evidence of fibrosis, suggesting sequelae of SARS-CoV-2 infection. Our findings indicate that specific effectors of the immune response in the lung and spleen were either increased or depleted in response to doses of SARS-CoV-2. This study demonstrated that the response of local and systemic immune effectors to a viral infection varies with viral dose, which either exacerbates the severity of the infection or accelerates its elimination.

Cytomegalovirus (CMV) is the most important opportunistic viral pathogen in solid organ transplant (SOT) recipients.The Korean guideline for the prevention of CMV infection in SOT recipients was developed jointly by the Korean Society for Infectious Diseases and the Korean Society of Transplantation. CMV serostatus of both donors and recipients should be screened before transplantation to best assess the risk of CMV infection after SOT. Seronegative recipients receiving organs from seropositive donors face the highest risk, followed by seropositive recipients. Either antiviral prophylaxis or preemptive therapy can be used to prevent CMV infection. While both strategies have been demonstrated to prevent CMV infection post-transplant, each has its own advantages and disadvantages. CMV serostatus, transplant organ, other risk factors, and practical issues should be considered for the selection of preventive measures. There is no universal viral load threshold to guide treatment in preemptive therapy. Each institution should define and validate its own threshold.Valganciclovir is the favored agent for both prophylaxis and preemptive therapy. The evaluation of CMV-specific cellmediated immunity and the monitoring of viral load kinetics are gaining interest, but there was insufficient evidence to issue recommendations. Specific considerations on pediatric transplant recipients are included.

Background: The benefits of transradial access (TRA) over transfemoral access (TFA) for bifurcation percutaneous coronary intervention (PCI) are uncertain because of the limited availability of device selection. This study aimed to compare the procedural differences and the in-hospital and long-term outcomes of TRA and TFA for bifurcation PCI using secondgeneration drug-eluting stents (DESs). Methods: Based on data from the Coronary Bifurcation Stenting Registry III, a retrospective registry of 2,648 patients undergoing bifurcation PCI with second-generation DES from 21 centers in South Korea, patients were categorized into the TRA group (n = 1,507) or the TFA group (n = 1,141). After propensity score matching (PSM), procedural differences, in-hospital outcomes, and device-oriented composite outcomes (DOCOs; a composite of cardiac death, target vessel-related myocardial infarction, and target lesion revascularization) were compared between the two groups (772 matched patients each group). Results: Despite well-balanced baseline clinical and lesion characteristics after PSM, the use of the two-stent strategy (14.2% vs. 23.7%, P = 0.001) and the incidence of in-hospital adverse outcomes, primarily driven by access site complications (2.2% vs. 4.4%, P = 0.015), were significantly lower in the TRA group than in the TFA group. At the 5-year follow-up, the incidence of DOCOs was similar between the groups (6.3% vs. 7.1%, P = 0.639). Conclusion The findings suggested that TRA may be safer than TFA for bifurcation PCI using second-generation DESs. Despite differences in treatment strategy, TRA was associated with similar long-term clinical outcomes as those of TFA. Therefore, TRA might be the preferred access for bifurcation PCI using second-generation DES.