A 20-Year Analysis of Ruptured Abdominal Aortic Aneurysm Outcomes and Associated Factors in Korea

BACKGROUND

Unlike western countries, which have reported distinct decreases in incidence of ruptured abdominal aortic aneurysm (rAAA) over the last few decades, epidemiologic studies in Korea have not shown significant changes in incidence or mortality of rAAA. The purpose of this study was to analyze the changes in rAAA treatment outcomes and various associated risk factors over the past 2 decades.

METHODS

A 20-year retrospective multicenter review for rAAA cases from the period of January 2000 to December 2020 was undertaken. Preoperative, intraoperative and postoperative clinical data were extracted for patients diagnosed with rAAA. For analysis, outcomes from the early era, defined as patients treated between January 1, 2000, and December 31, 2010, were compared with outcomes from the late era, defined as patients treated between January 1, 2011, and December 31, 2020.

RESULTS

The total in-hospital mortality was 34.1% in the early era compared to 44.8% in the late era. Patients in the late era were older than those in the early era (75.2 ± 10.3 years vs. 70.3 ± 8.9 years; P = 0.009). Treatment with rAAA endovascular aneurysm repair increased from 2.3% in early to 13.8% in late era (P = 0.031). In the early era, more patients were operated by experienced surgeons than the late era (78.1% vs. 45.9%; P = 0.002). The emergency room to operating room time did not show improvement over the 20 years.

CONCLUSIONS

The results indicate that mortality rate of rAAA in Korea has not changed over the last 2 decades. The study suggests the need for national preventive strategies, improved systemic coordination, and potential centralization of vascular services to enhance survival rates for rAAA.

Predicting factors for early failure of vascular access in hemodialysis patients

Purpose

This study aimed to investigate the incidence of early failure of vascular access for hemodialysis, and determine which factors measured in duplex ultrasound study could predict early failure.

Methods

We performed a retrospective review of patients who underwent arteriovenous fistula (AVF) or arteriovenous graft (AVG) creation for hemodialysis between September 2019 and January 2023. Early failure was defined as any event that required surgical or endovascular intervention within 6 months following AVF or AVG creation.

Results

A total of 189 patients were included. Early failure occurred in 36 patients (19.0%), which included 22 AVFs and 14 AVGs. In the patients who underwent AVF, the preoperative venous diameter, postoperative venous and arterial diameters, and flow volume of AVF all were significantly smaller in the early failure group compared to the patent group. In AVG, the preoperative venous diameter was the only parameter that differed between the 2 groups. A sonographic score was defined based on these factors. In a multivariable analysis, male sex, a previous history of AVF or AVG creation, and sonographic score were found to be significantly associated with early failure. The postoperative venous diameter in AVF and the preoperative venous diameter in AVG were highly predictive of early failure (areas under the curves 0.92 and 0.82, respectively).

Conclusion

Venous diameter measured 6 weeks following AVF operation and preoperative venous diameter in AVG were highly predictive of early failure among the duplex ultrasound parameters. Surveillance strategies in the early phase following vascular access creation can be based on these factors.

Tripartite motif-containing protein 26 promotes colorectal cancer growth by inactivating p53

Tripartite motif-containing protein 26 (TRIM26) is an E3 ubiquitin ligase that exhibits divergent roles in various cancer types (oncogenic and anti-oncogenic). This study investigates the interaction of TRIM26 with the tumor suppressor protein p53 in colorectal cancer (CRC) cells by performing a comprehensive set of biochemical, cell-based assays, and xenograft experiments. As a result, we found that overexpression of TRIM26 significantly enhances CRC cell proliferation and colony formation, while knockdown of TRIM26 suppresses these processes. Xenograft experiments further validated the tumor-promoting role of TRIM26 in CRC. Supporting this is that TRIM26 is highly expressed in human CRC tissues as revealed by our analysis of the TCGA database. Biochemically, TRIM26 directly bound to the C-terminus of p53 and facilitated its ubiquitination, resulting in proteolytic degradation and attenuated p53 activity independently of MDM2. Also, TRIM26 increased the MDM2-mediated ubiquitination of p53 by binding to MDM2's C-terminus. This study uncovers the oncogenic potential of TRIM26 in CRC by inhibiting p53 function. Through its ubiquitin ligase activity, TRIM26 destabilizes p53, consequently promoting CRC cell proliferation and tumor growth. These findings shed light on the complex involvement of TRIM26 in cancer and identify this ubiquitin ligase as a potential therapeutic target for future development of CRC treatment.

Clinical significance of the living kidney donor profile index for predicting long-term posttransplant outcomes: results from the Korean Organ Transplantation Registry

Background

The usefulness of the living kidney donor profile index (LKDPI) has not been widely demonstrated; therefore, it requires verification before clinical application. We analyzed the LKDPI using data from the Korean Organ Transplantation Registry (KOTRY) to confirm whether the LKDPI can be used to predict the survival of allografts in living donor kidney transplantation (LDKT) patients in Korea.

Methods

The study population was obtained from the KOTRY database. A total of 2,598 kidney recipients registered in the KOTRY database were enrolled between May 2014 and December 2020. Donor and recipient information was observed, and the LKDPI was measured.

Results

Median LKDPI score was 15.5 with a follow-up duration of 33.7 ± 16.1 months. According to LKDPI scores (group 1, <0; group 2, 0-20; group 3, 20-40; and group 4, >40), LKDPI group 4 had significantly higher death-censored graft loss than LKDPI group 1 (hazard ratio [HR], 1.89; 95% confidence interval [CI], 1.06- 3.40; p = 0.03). When divided based on the cutoff value (LKDPI, 36.6), the high LKDPI group had higher graft loss than the low LKDPI group (HR, 2.14; 95% CI, 1.37-3.34; p < 0.001). When follow-up was repeated after transplantation, it was confirmed that the higher the LKDPI value was, the lower the average estimated glomerular filtration rate (p < 0.001).

Conclusion

This study confirmed that LKDPI can serve as an independent predictor for assessing the risk of allograft failure and transplant outcomes in Korean LDKT patients.

Spontaneous Celiac Artery Dissection with Splenic Infarction: A Report of Two Cases

Spontaneous isolated celiac artery dissection (SICAD) is a rare condition that is characterized by sudden onset abdominal pain, typically occurring in middle-aged men. Although its clinical course is mostly benign, it may progress to true lumen occlusion. No established therapeutic guidelines are available for SICAD associated with splenic infarction. This report describes two patients who presented with sudden onset abdominal pain and were diagnosed with SICAD with splenic infarction based on computed tomography (CT) findings. Patients were treated with bowel rest and anticoagulants. After a week of medical therapy, the abdominal pain resolved. Follow-up CT revealed no progression of the dissection flap. The patients received oral anticoagulants for 3 months and did not experience any symptom recurrence. Medical therapy with anticoagulants may be considered for patients with SICAD and splenic infarction. Associated splenic infarction itself is not an indication for endovascular or surgical intervention for SICAD.

Validation of I71.3 code for ruptured abdominal aortic aneurysm in Korea: misplaced diagnosis in claims data

Purpose

Studies in western countries have shown a decline in the incidence of ruptured abdominal aortic aneurysm (rAAA) with advancements in endovascular repair and screening. However, according to health insurance data in Korea based on rAAA code (I71.3), overall rAAA has been increasing. This study aimed to validate the I71.3 code for rAAA and attempt to define the true incidence of rAAA in Korea.

Methods

A 20-year multicenter retrospective review of rAAA was undertaken from the period of January 1, 2000 to December 31, 2020. All patients were diagnosed with the rAAA code I71.3 in each of the 4 hospitals. The CT images and surgical records of these patients were reviewed to differentiate true rAAA and misdiagnosis. Further data on true rAAA patient outcomes including mortality and treatment success were also collected.

Results

A total of 305 rAAA (I71.3) codes were identified in the 4 centers. However, medical record review showed true rAAA in only 131 (43.0%). The remaining 174 cases (57.0%) were misdiagnosed. Impending ruptures were the most common misdiagnoses (37.9%). The total in-hospital mortality including deaths before treatment was 38.9% (n = 51), while mortality of treated patients was 24.4% (n = 15).

Conclusion

The analysis of I71.3 code for rAAA showed that only 43.0% were true rAAA and the remaining 57.0% were misdiagnosed. This indicates that the I71.3 code is overestimated in National Health Insurance-based data and that the true incidence of rAAA could be much lower.

A multicenter, randomized, open-labelled, non-inferiority trial of sustained-release sarpogrelate versus clopidogrel after femoropopliteal artery intervention

Optimal antiplatelet therapy after endovascular therapy (EVT) for peripheral artery disease is controversial. This trial aimed to evaluate whether sarpogrelate plus aspirin was non-inferior for preventing early restenosis after femoropopliteal (FP) EVT compared to clopidogrel plus aspirin. In this open-label, prospective randomized trial, 272 patients were enrolled after successful EVT for FP lesions. Patients in each group received aspirin 100 mg and clopidogrel 75 mg or sarpogrelate 300 mg orally once per day for 6 months. The primary outcome was target lesion restenosis at 6 months, tested for noninferiority. Patient characteristics and EVT patterns were similar, except for increased inflow procedures in the sarpogrelate group and increased outflow procedures in the clopidogrel group. The sarpogrelate group showed a tendency of less restenosis at 6 months than the clopidogrel group (13.0% vs. 19.1%, difference 6.1 percentage points, 95% CI for noninferiority - 0.047 to 0.169). Secondary endpoints related to safety outcomes were rare in both groups. Risks of target lesion restenosis of the two intervention arm were uniform across most major subgroups except for those with coronary artery disease. In conclusion, Sarpogrelate plus aspirin is non-inferior to clopidogrel plus aspirin in preventing early restenosis after FP EVT. Larger multi-ethnic trials are required to generalize these findings. Trial registration: National Institutes of Health Clinical Trials Registry (ClinicalTrials.gov identifier: NCT02959606; 09/11/2016).

Laparoscopic total extra-peritoneal (TEP) inguinal hernia repair under local anesthesia by topical lidocaine injection

PURPOSE

Laparoscopic total extra-peritoneal (TEP) inguinal hernia repair is usually performed under general anesthesia (GA) for muscle relaxation. However, TEP hernia repair may be reluctant in high-risk patients of GA. The aim of this study was to compare the outcomes of the TEP under GA and local anesthesia (LA).

METHODS

We retrospectively analyzed patients with inguinal hernia who underwent TEP under GA or LA in a single center from December 2016 to May 2018. The outcomes, such as demographics, duration of surgery, length of hospital stay, visual analog scale (VAS), and postoperative complications, were compared in each group.

RESULTS

Seventy-six patients with inguinal hernia underwent TEP under GA (n = 52) or LA (n = 24). Total operation time (mean ± standard deviation; GA, 111.6 ± 23.0 min; LA, 76.3 ± 18.0 min; p < 0.001) and length of hospital stay (GA, 38.3 ± 11.6 min; LA, 30.3 ± 15.6 min; p < 0.014) were shorter in LA group compared to GA group. There were no significant differences in postoperative VAS (1 h, p = 0.247; 4 h, p = 0.086; 12 h, p = 0.469; 24 h, p = 0.411), postoperative adverse effects (vomiting, p = 0.570; urinary retention, p = 0.214; headache, p = 0.494), and postoperative complications (seroma, p = 0.348; scrotal edema, p = 0.178; recurrence, p = 0.822) between LA group and GA group.

CONCLUSION

Compared with GA, there were no differences in postoperative pain and complications in patients who underwent TEP hernia repair under LA. Furthermore, in LA group, total operation time and length of hospital stay were shortened.

Effects of tacrolimus intrapatient variability and CYP3A5 polymorphism on the outcomes of pediatric kidney transplantation

BACKGROUND

The intrapatient variability (IPV) of tacrolimus (Tac) is associated with the long-term outcome of kidney transplantation. The CYP3A single-nucleotide polymorphism (SNP) may affect the IPV of Tac. We investigated the impact of IPV and genetic polymorphism in pediatric patients who received kidney transplantation.

METHODS

A total of 202 pediatric renal transplant recipients from 2000 to 2016 were analyzed retrospectively. The IPV was calculated between 6 and 12 months after surgery. Among these patients, CYP3A5 polymorphism was analyzed in 67 patients.

RESULTS

The group with high IPV had a significantly higher rate of de novo donor-specific human leukocyte antigen antibodies (dnDSA) development (35.7% vs. 16.7%, p = .003). The high IPV group also had a higher incidence of T-cell-mediated rejection (TCMR; p < .001). The high IPV had no significant influence on Epstein-Barr virus, cytomegalovirus, and BK virus viremia but was associated with the incidence of posttransplant lymphoproliferative disorders (p = .003). Overall, the graft survival rate was inferior in the high IPV group (p < .001). The CYP3A5 SNPs did not significantly affect the IPV of Tac. In the CYP3A5 expressor group, however, the IPV was significantly associated with the TCMR-free survival rate (p < .001).

CONCLUSION

The IPV of Tac had a significant impact on dnDSA development, occurrence of acute TCMR, and graft failure in pediatric patients who received renal transplantation. CYP3A5 expressors with high IPV of Tac showed worse outcomes, while the CYP3A5 polymorphism had no impact on IPV of Tac.

Vein Graft Aneurysm after Aorto-Renal Bypass for Childhood Renovascular Hypertension Due to Fibromuscular Dysplasia

Renovascular hypertension (RVHT) is a major cause of surgically correctable secondary hypertension. Refractory hypertension despite multiple antihypertensive drugs requires angioplasty, surgical revascularization, or even nephrectomy. Herein, we report a pediatric patient who had been treated with angioplasty, nephrectomy, and aortorenal bypass surgery for RVHT due to fibromuscular dysplasia and re-do endoaneurysmal graft replacement for a vein graft aneurysm. This case highlights the various treatment modalities for RVHT and the recurrent nature of the disease with a rare presentation of a vein graft aneurysm after aortorenal bypass.

Activin Suppresses the Inflammatory Response of TNF-α -stimulated Human Umbilical Vein Endothelial Cells

Activins belong to the transforming growth factor (TGF)-β superfamily and are involved in the regulation of homeostasis, proliferation, differentiation, and inflammation. In the present study, we examined the mechanism by which activin regulates the transcription of tumor necrosis factor-α (TNF-α)-stimulated cytokines, chemokines, toll-like receptors (TLRs), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in human umbilical vein endothelial cells (HUVECs), and the involvement of the nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Cell viability was analyzed using MTS/PES solution, mRNA expression was measured by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and protein expression was measured by immunoblotting. TNF-α increased the mRNA expression of cytokines (IL-1β and IL-6), chemokines (IL-8 and MCP-1), and TLR2, as well as the mRNA and protein expression of iNOS and COX-2. Activin decreased TNF-α-induced cytokine, chemokine, and TLR mRNA expression as well as TNF-α-induced iNOS and COX-2 mRNA and protein expression. In addition, activin suppressed the phosphorylation of NF-κB p65 in TNF-α-stimulated HUVECs and reduced TNF-α-induced phosphorylation of AKT, JNK, ERK, and p38 MAPK. Our results demonstrate that the anti-inflammatory effects of activin are mediated by inflammatory response genes through the inhibition of NF-κB and AKT/JNK/MAPK signaling.

Causes and symptoms of varicose veins

Background: Varicose veins are a common disease that cause edema, heaviness, pigmentation, and skin ulcers, ultimately affecting the quality of life. Various treatments have recently been developed; therefore, clinicians need to understand the anatomy, pathophysiology, risk factors, and symptoms of varicose veins to provide optimal treatment.Current Concepts: Lower extremity veins are composed of deep, superficial, perforating, and communicating vein systems, and the main axial superficial veins are composed of the great and small saphenous veins. Venous circulation primarily relies on muscle pumps in the foot and calf. Pressure on the sole and contraction of calf muscles compress the veins, sending blood upward or to the deep vein system. Varicose veins are caused by valvular abnormalities, muscle pump failure, etc., and associated risk factors include age, pregnancy, obesity, and family history. The main symptoms include heaviness, fatigue, and edema.Discussion and Conclusion: Varicose veins have complex anatomical structures and are developed by various factors. Therefore, appropriate treatments should be selected considering patients’ symptoms, anatomical structure, and economic aspects.

A214 SIMPLIFICATION OF CARE FOR HCV IS EFFECTIVE DURING THE COVID PANDEMIC: A RETROSPECTIVE STUDY OF HCV TREATMENT UTILIZING THE BRITISH COLUMBIA HEPATITIS C NETWORK

Background

The COVID-19 pandemic has impacted healthcare access, including to curative treatment for hepatitis C (HCV) infection in the form of direct-acting antivirals (DAAs). A 49% decrease in DAA dispensations in Canada during the pandemic has been reported, but little is known about these treated populations.

Aims

To explore the patient characteristics and treatment patterns in those who were treated for HCV during the COVID pandemic.

Methods

A retrospective chart review was conducted at one site of utilizing the British Columbia Hepatitis C Network. Only patients included into the database were analyzed. Patients started on treatment between 03/17/2020-03/16/2021 were included as the “pandemic group” and patients from the 03/17/2019-03/16/2020 were included as a comparison “pre-pandemic group”. Data were extracted for clinicodemographic variables, laboratory investigations, treatment start date, regimen, and sustained virologic response at 12 weeks (SVR12).

Results

97 patients were treated during the pandemic compared to 143 patients the year prior, representing a 32% decline. Patients treated during the pandemic were predominantly new referrals (n=70, 72% vs n=64, 45% pre-pandemic, p&lt;0.01) and had fewer total appointments (median 2 per patient vs 4 per patient pre-pandemic, p&lt;0.01). There was a median of 1 in-person visit and 1 telehealth appointment per patient during the pandemic (vs median 2 per patient of each type pre-pandemic).

Pandemic patients were younger (mean age 56.0 years vs 59.6 pre-pandemic, p=0.04), and a greater proportion were on opioid agonist therapy (28% vs 13% pre-pandemic, p&lt;0.01). Less transient elastography (TE) was performed during the pandemic (69% vs 89% pre-pandemic). Amongst those with TE scores, a lower proportion of those treated during the pandemic were cirrhotic (13% vs 21% pre-pandemic).

During the pandemic, treatment patterns shifted towards more prescriptions for glecaprevir/pibrentasvir (56% of all prescriptions vs 44% pre-pandemic) and sofosbuvir/velpatasvir (37% vs 29% pre-pandemic). There was slightly less use of sofosbuvir/velpatasvir/voxilaprevir at (2% vs 4% pre-pandemic).

The proportion of patients who completed lab work for SVR was similar during the pandemic (n=83/97, 85.6%) compared to pre-pandemic (n=120/143, 83.9%). Similarly, SVR12 remained high during the pandemic at 98.7% (vs 99.3% pre-pandemic). Of all 97 patients prescribed DAAs during the pandemic, 92 (94.8%) completed treatment.

Conclusions

Less persons were treated during the COVID pandemic, which may deter progress towards HCV elimination targets. Very high SVR12 and treatment completion rates during the pandemic suggest that patients can be effectively treated with less pre-treatment investigations and fewer appointments.

Funding Agencies

None

Effects of Substance P for Liver Regeneration in Rat Hepatectomy Models: A Preliminary Experimental Animal Study

Background

Material/Methods

Results

Conclusions

Methylation and mutation of the inhibin‑α gene in human melanoma cells and regulation of PTEN expression and AKT/PI3K signaling by a demethylating agent

Inhibin suppresses the pituitary secretion of follicle‑stimulating hormone and has been reported to act as a tumor suppressor gene in the gonad in mice. Epigenetic modifications, mutations, changes in the loss of heterozygosity (LOH) of the inhibin‑α gene and regulation of gene expression in response to a demethylating agent [5‑aza‑2'‑deoxycytidine (5‑Aza‑dC)] in human melanoma cells were assessed. In addition, the association between a mutation in the 5'‑untranslated region (5'‑UTR) of the inhibin‑α subunit and the expression of phosphatidylinositol 3,4,5‑trisphosphate‑dependent Rac exchanger 2 (PREX2) and phosphatase and tensin homolog (PTEN) as well as AKT/PI3K signaling was determined. The methylation status of the CpG sites of the inhibin‑α promoter was analyzed by methylation‑specific PCR in bisulfite‑treated DNA. Cell viability was counted using the trypan blue assay, mRNA expression was examined via reverse transcription‑quantitative PCR, and protein expression was examined via western blot analysis. The inhibin‑α promoter was hypermethylated in G361, SK‑MEL‑3, SK‑MEL‑24 and SK‑MEL‑28 cells and moderately methylated in SK‑MEL‑5 cells. Inhibin‑α gene mutations were observed in the 5'‑UTR exon 1 of G361, SK‑MEL‑5, SK‑MEL‑24 and SK‑MEL‑28 cells as well as in exon 2 of SK‑MEL‑3 cells. Allelic imbalance, including LOH, in the inhibin‑α gene was detected in human melanoma cells. Treatment with 5‑Aza‑dC increased inhibin‑α mRNA and protein levels, inhibited cell proliferation, and delayed the doubling times of surviving melanoma cells. In 5‑Aza‑dC‑treated cells, PREX2 protein expression was slightly increased in G361 and SK‑MEL‑24 cells and decreased in SK‑MEL3, SK‑MEL‑5 and SK‑MEL‑28 cells. However, the protein expression of PTEN was decreased in melanoma cells. In addition, AKT and PI3K protein phosphorylation levels increased in all melanoma cells, except of G361 cells, demonstrating decreased PI3K protein phosphorylation. These data provided evidence that methylation, mutation and LOH are observed in the inhibin α‑subunit gene and gene locus in human melanoma cells. Furthermore, the demethylating agent reactivated inhibin‑α gene expression and regulated PREX2 expression. AKT/PI3K signaling increased as PTEN expression decreased. In addition, mutations in the tumor suppressor inhibin‑α, PTEN and p53 genes were not associated with transcriptional silencing, gene expression and cell growth as analyzed through experiments and literature reviews. These data demonstrated that methylation and mutations were associated with the inhibin‑α gene in human melanoma cells and indicated the regulation of PTEN expression and AKT/PI3K signaling by a demethylating agent.

Comparison between autogenous brachial-brachial upper-arm elevated direct arteriovenous fistulas and prosthetic brachial-antecubital indirect forearm arteriovenous grafts

OBJECTIVES

The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) guidelines recommend forearm arteriovenous grafts (AVGs) as an alternative procedure to transposed basilic vein fistulas for providing secondary access during hemodialysis. Recently, autogenous elevated brachial-brachial vein fistulas (BVE) have become increasingly popular. The aim of this study was to compare the outcomes of BVE and forearm loop AVG (AVG) for secondary access in hemodialysis.

METHODS

We retrospectively reviewed the medical records of patients who had received a BVE or forearm AVG at a single center from January 2015 to April 2019. In total, 19 BVE were created via two-stage operations and two via a one-stage operation; 53 forearm AVG's were performed.

RESULTS

The AVG group was twice as likely to suffer loss of primary patency compared with the BVE group (odds ratio [OR], 2.666; 95% confidence interval [CI], 1.108-6.412; p = 0.029) per the multivariate analysis. The primary patency and primary assisted patency of the BVE group were superior those of the AVG group, except for secondary patency (p = 0.02, p = 0.07, p = 0.879, respectively). In subgroup analysis, there were no significant differences in primary, primary assisted, or secondary patency between AVG and BVE when brachial vein was used for AVG outflow. In addition, no significant differences were noted regarding the infection rate (12.5% vs 12.3%, p = 0.331, severity >0), postoperative bleeding rate (14.5% vs 3.5%, p = 0.191, severity >1), early thrombus rate (0.0% vs 10.5%, p = 0.122), and early failure rate (7% vs 4.8%, p = 0.591).

CONCLUSIONS

The primary patency and primary assisted patency rates of BVE were significantly better than those observed in AVGs, but the complication rates were similar. The appropriate procedure to provide vascular access should be determined by the individual patient's condition and the surgical skill of the operating surgeon.

Stump Length Changes after Endovenous Cyanoacrylate Closure or Radiofrequency Ablation for Saphenous Vein Incompetence

Purpose

The aim of this study was to analyze changes in stump length over time in patients with saphenous vein incompetence treated with cyanoacrylate closure (CAC) or radiofrequency ablation (RFA).

Methods

Materials and We retrospectively analyzed data collected from patients with saphenous vein incompetence who underwent either CAC or RFA at Seoul National University Hospital between November 2015 and December 2018. The stump lengths were measured using duplex ultrasonography (DUS) within 1 month and 6 months after treatment. The Venous Clinical Severity Score (VCSS) and Aberdeen Varicose Vein Questionnaire (AVVQ) score were used to assess clinical outcomes.

Results

A total of 97 veins (64 great saphenous veins and 33 small saphenous veins) were analyzed. The stump length was not significantly different between the two groups at <1 month (P=0.311). However, the stump length in the CAC group was significantly longer than that in the RFA group at 6 months (P=0.004). At 6 months, the mean change in stump length was 1.41±2.28 cm in the CAC group and 0.51±0.54 cm in the RFA group (P=0.006). The VCSSs and AVVQ scores significantly improved after both procedures but were not significantly different between the two groups.

Conclusion

DUS at 6 months after treatment showed that the stump length in the CAC group increased more than that in the RFA group. No other factors affected the changes in stump length.

Better Efficacy of Balloon Assisted Maturation in Radial-Cephalic Arteriovenous Fistula for Hemodialysis

Purpose

Native arteriovenous fistula (AVF) is the first choice for hemodialysis access; however, the maturation failure rate remains high. Hence, balloon-assisted maturation (BAM) is increasingly being used to overcome maturation failure. This study evaluated the outcomes of BAM and compared the differences between radial-cephalic (RC) and brachial-cephalic (BC) AVF.

Methods

Materials and Between January 2013 and December 2017, 1,622 new AVFs were created. BAM was considered if the AVF did not satisfy the criteria for hemodynamic maturation (6-mm diameter and 500-mL/min flow rate within 8 weeks after the operation).

Results

Of the 1,622 AVFs, BAM was performed in 142 patients (8.75%). There were 92 RC and 50 BC AVFs. Multivariate analyses revealed that ipsilateral central vein catheter history was the sole risk factor for maturation failure after BAM. One-year functional primary patency (FPP) and functional secondary patency (FSP) in RC AVFs were higher than those in BC AVFs without statistical significance (FPP, RC vs. BC: 70.9% vs. 50.9%, P=0.099; FSP, 95.5% vs. 81.1%, P=0.146). Further, based on the multivariate analysis, the independent risk factors for FPP in the RC and BC AVFs were the number of BAMs (odds ratio [OR], 3.05; 95% confidence interval [CI], 1.11-8.37; P=0.03) and age (OR, 1.04; 95% CI, 1.00-1.07; P=0.04), respectively.

Conclusion

BAM is a relatively good salvage method with tolerable patency. However, the risk factors for patency and the outcomes of BAM differ between RC and BC AVFs.

A164 PATTERNS IN MEDICAL THERAPY AND CLINICAL OUTCOMES IN PATIENTS WITH CONCOMITANT INFLAMMATORY BOWEL DISEASE AND PRIMARY SCLEROSING CHOLANGITIS: A SINGLE CENTRE RETROSPECTIVE ANALYSIS

Background

Inflammatory bowel disease (IBD) in patients with primary sclerosing cholangitis (PSC) is characterized by pancolitis with rectal sparing and is associated with an increased risk of colorectal and biliary malignancies. Currently, pharmacologic management of IBD in the setting of PSC is the same as in IBD alone.

Aims

To assess patterns in medical therapy, and incidence of adverse outcomes in patients with concomitant IBD and PSC.

Methods

A retrospective review was conducted on all PSC-IBD patients followed between January 2010 and June 2018. The Endoscopic Mayo Score was used to grade IBD severity in PSC-ulcerative colitis (UC).

Results

69 patients were identified, 44 (63.8%) were male. The mean ages of IBD and PSC diagnosis were 28.6 (SD 14.9) and 37.0 (SD 18.9) years, respectively. The median length of follow up was 12 (range 2–49) years. 52 (75.4%) patients had UC, and 17 (24.6%) had Crohn’s disease (CD). 28 (87.5%) PSC-UC patients had pancolitis, and 4 (12.5 %) had proctitis. Among those with pancolitis, 8 (28.6%) had relative rectal sparing. 4 (14.3%) patients had more severe inflammation proximally, whereas only 1 (3.6%) had more severe distal inflammation. 23 (82.1%) patients had the same degree of inflammation throughout. 14 (93.3%) PSC-CD patients had colitis/ileocolitis and 1 (6.7%) had ileitis. Among those with PSC-UC, 16 (50.0%), 12 (37.5%), and 4 (12.5%) patients had grade 1, 2, and 3 disease, respectively. 62 (89.9%) PSC-IBD patients were treated with aminosalicylates, and 26 (37.7%) with biologics at some point in their IBD course. 26 (37.7%) were treated with aminosalicylates alone. 4 (5.8%) did not require any IBD therapy. Cholangiocarcinoma, colorectal cancer, and gallbladder cancer developed in 8 (11.6%), 1 (1.4%), and 1 (1.4%) PSC-IBD patients, respectively. 16 (23.2%) patients required partial or total colectomy. Indication for surgery was inflammation or stenosis, dysplasia, and neoplasia in 13 (81.3%), 2 (12.5%), and 1 (6.3%) patients, respectively.

Conclusions

The majority of this cohort had UC with mild disease activity. Pancolitis was common, with frequent rectal sparing and more severe right-sided inflammation. Despite the predominance of low-grade colitis, a large portion of patients required treatment with biologics. The incidence of adverse outcomes underscores the need for strict adherence to recommended surveillance practices. Low grade endoscopic activity, typical of the quiescent IBD course in PSC-IBD, may mask low grade histologic inflammation, which in turn may contribute to the increased risk of colonic neoplasia. Further studies are needed to determine the best management strategy for IBD in patients with PSC.

Funding Agencies

None

A208 PREDICTORS OF OUTCOMES IN PSC: RETROSPECTIVE ANALYSIS OF TWO TERTIARY CARE CENTERS IN BC

Background

Primary sclerosing cholangitis (PSC) is a chronic inflammatory disorder of the bile ducts. PSC can rapidly progress to cholangiocarcinoma and death. Many clinical features of PSC, as well as its relationship with diseases such as IBD, remain ill-defined. These features are important for disease modeling and clinical trial design.

Aims

To identify features of PSC that may aid in disease modeling and outcomes prediction.

Methods

Patients with a diagnosis of PSC with visits between 2012 and 2018 were identified and data were extracted. Survival analysis was performed, with time defined as time of PSC diagnosis to time at clinical endpoint. The clinical endpoint for survival analysis was defined as development of cholangiocarcinoma, liver transplantation or death. Univariate and multivariate Cox-regression was then performed.

Results

169 patients (99 male, 70 female) were identified. Of these, 102 (60.4%) had a diagnosis of IBD (84 UC). 138 were Caucasian, 9 East Asian, 9 South Asian and 13 Middle East. Mean age at PSC diagnosis was 39.3, IBD diagnosis 29.3 years. Mean time to next diagnosis in those with PSC-IBD was 7.7 years. Of those with PSC-IBD, IBD preceded the diagnosis of PSC in 69 (67.6%) patients. 22 (13.0%) had concurrent liver disease, including 14 AIH and 1 PBC overlap. In those with UC, disease was most often pancolitis (57.8%), with noticeable rate of backwash ileitis (23.3%). There were 26 patients with current or prior use of Infliximab, 14 with Humira, and 6 with Vedolizumab. 28 (16.6%) patients had a partial or total colectomy. 35 (20.7%) patients had diagnoses of cancer, including 16 cholangiocarcinoma, 2 gall bladder carcinoma, and 4 colorectal. 33 (19.5%) patients received liver transplant, and 31 (18.3%) died. Most frequent cause of death was cholangiocarcinoma (12, 38.7%). Univariate analysis identified increased age at PSC diagnosis, presence of IBD, increased age at IBD diagnosis, diagnosis of IBD prior to PSC, increased time from diagnosis of IBD to PSC, diagnosis of UC as opposed to Crohn’s, and lack of Infliximab use as significant predictors of our clinical endpoints (p&lt;0.05). Multivariate analysis only identified increased age at PSC diagnosis, presence of IBD, and diagnosis of IBD prior to PSC as predictors.

Conclusions

PSC affects persons of various ethnic backgrounds. Diagnosis of IBD appears to precede PSC in most PSC-IBD cases, and the temporal relationship may impact outcomes, possibly due to delayed diagnosis of PSC. UC has a worse disease course than Crohn’s. Cholangiocarcinoma still accounts for a large burden of overall death in PSC, and strategies for early diagnosis should be explored. More studies are required to delineate the relationship between biologic use and PSC outcomes. The major limitation of our study is the smaller sample size that may have limited statistical power.

Funding Agencies

NoneNone

Single versus en bloc kidney transplant from donors less than or equal to 15 kg to pediatric recipients

With small kidneys, EBKTs could provide sufficient renal mass but could lead to inefficient use of resources, while SKTs could result in insufficient function due to small renal mass. We aimed to compare the outcomes of EBKT and SKT from small donors weighing ≤15 kg to pediatric recipients. We retrospectively reviewed all pediatric patients who met the inclusion criteria between January 1, 1984, and April 30, 2019, at a single institution. Of a total of 23 patients, 12 received EBKT and 11 received SKT. The median age of donors, weight of donors, and weight of recipients were comparable between the two groups. The median age of recipients and median weight of allografts were greater in the EBKT group than in the SKT group. The median follow-up was 53.9 months. There was no significant difference in eGFR, protein creatinine ratios at 1-year follow-up, and overall graft survival. The size of the kidney increased by approximately 13%-43% in the EBKT group and 40%-60% in the SKT group. This study demonstrated that kidneys from small donors weighing 5-15 kg could be split in pediatric recipients without compromising the outcome.

Renal transplantation in patients with an augmentation cystoplasty

Background

The effects of renal transplantation in patients with augmentation cystoplasty are still controversial. We retrospectively analyzed nine patients who underwent renal transplantation after augmentation cystoplasty.

Methods

A total of nine patients who underwent augmentation cystoplasty prior to renal transplantation between January 1990 and May 2020 were reviewed. Basic information on augmentation cystoplasty, transplant procedures, and long-term outcomes of renal transplantation were analyzed.

Results

The bowel segments utilized for augmentation cystoplasty were the stomach in two patients (one patient needed revision using the ileum), the ileum in four patients, the ileocolic pouch in one patient, the sigmoid in one patient, and the ureter in one patient. All the cystoplasties were performed prior to renal transplantation. The mean follow-up period after transplantation was 161 months (range, 2–341 months). Two patients had an episode of acute rejection each; however, their graft functions were well-maintained. Five patients had recurrent urinary tract infections, and three of these patients progressed to allograft failure. One patient died from bladder cancer with a functioning graft. Five of nine patients showed well-maintained graft function.

Conclusions

Renal transplantation after bladder augmentation surgery is a major operation requiring a high level of surgical skill. Based on our long-term experiences, we recommend diligent postoperative monitoring for urinary tract infections, optimal catheter use, and use of appropriate antibiotic prophylaxis to avoid severe complications.

Uniform spatial pooling explains topographic organization and deviation from receptive-field scale invariance in primate V1

Receptive field (RF) size and preferred spatial frequency (SF) vary greatly across the primary visual cortex (V1), increasing in a scale invariant fashion with eccentricity. Recent studies reveal that preferred SF also forms a fine-scale periodic map. A fundamental open question is how local variability in preferred SF is tied to the overall spatial RF. Here, we use two-photon imaging to simultaneously measure maps of RF size, phase selectivity, SF bandwidth, and orientation bandwidth—all of which were found to be topographically organized and correlate with preferred SF. Each of these newly characterized inter-map relationships strongly deviate from scale invariance, yet reveal a common motif—they are all accounted for by a model with uniform spatial pooling from scale invariant inputs. Our results and model provide novel and quantitative understanding of the output from V1 to downstream circuits.

Two-photon imaging in macaque V1 captured maps of tuning selectivity for four spatial parameters, all of which correlated with peak spatial frequency. These inter-map relationships reveal a common motif—they are described by uniform spatial pooling from a family of scale invariant Gabor receptive fields.

Recanalization of an Occluded Vena Cava Filter and Iliac Veins with Kissing Stents to Treat Postthrombotic Syndrome with a Venous Stasis Ulcer

Inferior vena cava filters (IVCFs) are effective in preventing pulmonary embolism and their usage has rapidly increased over the past decades. However, complications have also significantly increased, as IVCF occlusion causes serious chronic venous insufficiency. Herein, we report a case of infrarenal IVCF occlusion that was successfully treated with the introduction of kissing stents through the IVCF into both iliac veins. A 54-year-old male presented with non-healing ulcers on his left leg. He had undergone IVCF implantation and warfarin medication due to deep vein thrombosis 4 years earlier in another hospital. Computed tomography (CT) revealed the filter-bearing IVC occlusion. Endovascular IVCF removal was attempted but failed. Kissing stents were deployed across the IVCF and extended into both iliac veins. Cone beam CT showed well-deployed stents just behind the occluded IVCF. Venous flow was restored without complications, and the recurrent ulcer healed immediately.

A136 PREDICTIVE FACTORS OF CIRRHOSIS IN HCV PATIENTS WITH LOW PRE-TREATMENT APRI AND/OR FIB-4 SCORES

Background

It is essential to evaluate the stage of hepatic fibrosis prior to the initiation of HCV therapy. In addition to being a major prognostic factor, the presence of cirrhosis requires monitoring for hepatocellular carcinoma (HCC), esophageal varices, and decompensated liver disease. In some cases the presence of cirrhosis may affect the choice of therapy. In tertiary hepatology clinics, transient elastography (TE) is routinely used to assess fibrosis; however access to TE is limited. Fibrosis-4 (FIB4) and AST-to-platelet ratio index (APRI) are simple, easily available non-invasive methods of fibrosis measurement based on routine serum biomarkers. Studies evaluating HCV treatment pathways have reported that the use of FIB4 and APRI are cost-effective strategies for excluding cirrhosis thereby reducing the need for TE prior to treatment. Although the NPV of these tests are well described, a minority of patients will have advanced fibrosis despite low APRI and/or FIB4 scores.

Aims

To investigate predictive factors of cirrhosis in HCV patients with low pre-treatment APRI and/or FIB-4 scores.

Methods

Retrospective observational study with data obtained from the Pacific Gastroenterology Associates (PGA), a tertiary care outpatient Gastroenterology clinic located in Vancouver, British Columbia. Inclusions: Chronic HCV patients treated between Jan 2015 to 2019, pre-treatment TE values ≥12.5 kPa, FIB-4 &lt;1.45 and/or APRI &lt;0.7. Exclusions: those without cirrhosis, or incomplete evaluation prior to HCV treatment. Cirrhosis was defined as those with TE ≥12.5 kPa with clinical, radiographic, or pathologic features of cirrhosis.

Results

52 patients were identified. 11 patients did not have clinical, radiographic, or pathologic features of cirrhosis and 3 patients were excluded for insufficient data. Thus, 39 patients were included in multivariate analysis. The mean age was 59 years and 66% (25/38) were male gender. 10% (4/38) were Genotype 3 (G3). Presence of G3 was not included in the multivariate analysis due to low number of observations.

Conclusions

Generally, an APRI &lt;0.7 and FIB-4 &lt;1.45 have good test characteristics for excluding fibrosis. Our study demonstrates that patients with obesity, dyslipidemia, excessive alcohol use, or known steatosis on ultrasound may have cirrhosis despite low serum biomarker scores. Co-existence of other liver diseases such as alcohol related or non-alcoholic fatty liver disease (NAFLD) should prompt further evaluation for fibrosis assessment beyond biomarkers as these persons may have more advanced liver disease.

Funding Agencies

None

A186 HEPATIC STEATOSIS PREDICTS FIBROSIS IN LONG-TERM METHOTREXATE USE

Background

Methotrexate (MTX) is effective for dermatologic and rheumatologic conditions such as psoriasis (Ps), psoriatic arthritis (PsO) and rheumatoid arthritis (RA). Long-term MTX use may be complicated by hepatic fibrosis, although patient, disease factors and the mechanism remain unclear. Transient elastography (TE) is a non-invasive measure of hepatic fibrosis that is often used as surveillance in this patient population.

Patients with Ps and PsO have higher rates of non-alcoholic fatty liver disease. The controlled attenuation parameter (CAP) measurement is a non-invasive test that correlates with histologic degree of steatosis. To our knowledge, no studies have evaluated hepatic steatosis via CAP scores in MTX use.

Aims

To determine the prevalence of steatosis and significant fibrosis (F≥stage 2) in persons on MTX therapy and to determine the predictive factors for these events.

Methods

A single centred retrospective cohort study was performed. Patients on &gt;6 months of MTX for a dermatologic or rheumatologic disease who had undergone TE from January 2015 to September 2019 were included. Demographic variables, laboratory investigations, TE and CAP scores were collected. Multivariate analysis was performed to determine predictors of steatosis and fibrosis.

Results

A total of 177 patients on methotrexate were included. Ps was the most frequent diagnosis (n=52) followed by RA (n=50) and PsO (n=38). Steatosis (CAP≥245 dB/m) was present in 73.9% of patients. Patients with steatosis had significantly more fibrosis and a higher BMI than those without steatosis (CAP&lt;245 dB/m). Higher CAP score was correlated with increased lifetime dose of methotrexate by Pearson correlation analysis (r=0.48, p=0.001) (n=85 patients). Multivariate regression analysis revealed that diabetes mellitus (OR 10.5, 95% CI 1.38–80.60), hypertension (OR 4.97, 95% CI 1.66–14.84), and BMI&gt; 30 (OR 10.1, 95% CI 1.88–37.14) were predictors of steatosis (CAP≥245 dB/m). Predictors of METAVIR≥F2 (TE≥8.0 kPa) by multivariate regression analysis included CAP score of ≥270 (OR 8.36, 95% CI 1.88–37.14), diabetes mellitus (OR 2.85, 95% CI 1.09–7.48), hypertension (OR 5.4, 95% CI 2.23–13.0), dyslipidemia (OR 3.71, 95% CI 1.50–9.18) and alcohol use (OR 3.06, 95% CI 1.2–7.49).

Conclusions

In patients on MTX for rheumatologic and dermatologic diseases, hepatic steatosis was common and predicted significant fibrosis. Additionally, increasing MTX exposure is correlated with steatosis. Features of the metabolic syndrome including diabetes, hypertension or obesity were predictors of both steatosis and fibrosis (F≥2). Further study is needed to evaluate if steatosis is a mechanism by which fibrosis occurs in patients on MTX, or if it due to other patient factors.

Funding Agencies

None

Thrombosis of a Long-Segment Aneurysm from the Iliac to Popliteal Artery Associated with Arteriovenous Malformation and Varicose Veins

A 58-year-old male patient with severe claudication due to thrombosis of the left ilio-femoro-popliteal artery aneurysm. He also had a venous stasis ulcer with a history of multiple embolotherapy of arteriovenous malformation. Duplex sonography revealed reflux and varicose veins of the left great saphenous vein (GSV). A sequential bypass surgery was performed that consisted of excision of the left external iliac and common femoral artery aneurysm, external iliac to deep femoral interposition with an expanded polytetrafluoroethylene graft, and femoro-posterior tibial artery bypass with the reversed left GSV. Symptoms of claudication were alleviated and the chronic ulcer was healed in time. To our knowledge, this is the first report of successful bypass in a patient with arterial aneurysm, arteriovenous malformation, and venous insufficiency that can be diagnosed as an atypical case of Parkes Weber syndrome. Long-term follow-up is needed to define the fate of aneurysms and varicose vein graft.

Twelve-day medium pumping into tubular cell-laden scaffold using a lab-made PDMS connector

In the current study, a method is proposed to supply culture medium into a two-layered cell-laden tubular scaffold in order to enhance cell proliferation, confluence, and viability. The two-layered cell-laden tubular scaffold was made of calcium-alginate mixed with fibroblast cells (NIH/3T3) using a lab-made double- coaxial laminar-flow generator. Afterwards, the tubular scaffold was connected to a syringe pump system using a polydimethylsiloxane (PDMS) micro-connector for long-term cell culture. Three medium pumping conditions were applied and compared: a heart-beat-mimicking pumping (20 µL/s, 1 s period, and 50 % pulse width), a continuous pumping (20 µL/s) and a non-pumping. Non-leaky connections between the tubular scaffolds and the micro-connector outlet were sustained for 13.5 ± 0.83 d in heartbeat-mimicking pumping and 11.8 ± 0.33 d in continuous pumping condition, due to the elasticity of the tubular scaffolds. Importantly, the two pumping conditions resulted in more cell proliferation, confluence, and viability than the non-pumping condition. Furthermore, analysis of newly-produced type-I collagen matrix indicated that the cells under the two pumping conditions formed a tissue-like structure. The proposed technique could further be applied to vascular co-culturing for vascular engineered tissue.

Bioinks and bioprinting technologies to make heterogeneous and biomimetic tissue constructs

The native tissues are complex structures consisting of different cell types, extracellular matrix materials, and biomolecules. Traditional tissue engineering strategies have not been able to fully reproduce biomimetic and heterogeneous tissue constructs because of the lack of appropriate biomaterials and technologies. However, recently developed three-dimensional bioprinting techniques can be leveraged to produce biomimetic and complex tissue structures. To achieve this, multicomponent bioinks composed of multiple biomaterials (natural, synthetic, or hybrid natural-synthetic biomaterials), different types of cells, and soluble factors have been developed. In addition, advanced bioprinting technologies have enabled us to print multimaterial bioinks with spatial and microscale resolution in a rapid and continuous manner, aiming to reproduce the complex architecture of the native tissues. This review highlights important advances in heterogeneous bioinks and bioprinting technologies to fabricate biomimetic tissue constructs. Opportunities and challenges to further accelerate this research area are also described.