Treatment Outcomes of Patients With Ruptured Abdominal Aortic Aneurysms.

BACKGROUND: Ruptured abdominal aortic aneurysm (rAAA) is a serious complication of abdominal aortic aneurysm associated with high operative mortality and morbidity rates. The present study evaluated the perioperative and long-term outcomes of Korean patients with rAAA based on national health insurance claims data. METHODS: The National Health Insurance Service (NHIS) database was searched retrospectively to identify patients with rAAA who underwent endovascular aneurysm repair (EVAR) and open surgical repair (OSR) from 2009 to 2018. Perioperative (≤ 30 days), early postoperative (≤ 3 month), and long-term (> 3 month) survival, reinterventions, and complications were assessed. RESULTS: The search identified 1,034 patients with rAAA, including 594 who underwent EVAR and 440 who underwent OSR. When the study period was divided into two, the total numbers of patients with rAAA, patients who underwent EVAR, and octogenarians were higher during the second half. The perioperative mortality rate was 29.8% in the EVAR and 35.0% in the OSR group (P = 0.028). Hartmann's procedure for bowel infarction was performed more frequently in the OSR than in the EVAR group (adjusted odds ratio, 6.28; 95% confidence interval [CI], 2.33-21.84; P = 0.001), but other complication rates did not differ significantly. All-cause mortality during the entire observation period did not differ significantly in the EVAR and OSR groups (adjusted hazard ratio, 1.17; 95% CI, 0.98-1.41; P = 0.087). Abdominal aortic aneurysm-related reintervention rate was significantly lower in the OSR group (adjusted hazard ratio, 0.31; 95% CI, 0.14-0.70; P = 0.005). CONCLUSION: Although EVAR showed somewhat superior perioperative outcomes for rAAA, the long-term outcomes of EVAR after excluding initial 3 months were significantly worse than OSR. When anatomically feasible for both treatments, the perioperative mortality risk and reasonable prospects of long-term survival should be considered in rAAA.

Twinfilin-1 is an essential regulator of myogenic differentiation through the modulation of YAP in C2C12 myoblasts.

Actin cytoskeletal dynamics play a critical role in the regulation of myogenesis through mechanotransduction, Hippo signaling modulation, cell proliferation, and morphological changes. Although Twinfilin-1 (TWF1), a highly conserved actin-depolymerizing factor, is known to regulate actin filament assembly by sequestering actin monomer and capping barbed ends, the biological significance of TWF1 during the differentiation of myogenic progenitor cells has not been investigated. In this study, we unveiled the roles played by TWF1 in the proliferation and differentiation of C2C12 myoblasts. TWF1 was the predominant isoform in myoblasts, and its expression was induced during the early stage of differentiation. Knockdown of TWF1 by siRNA (siTWF1) induced the accumulation of actin filaments (F-actin) and promoted the nuclear translocation of Yes-associated protein (YAP) in the Hippo signaling pathway. TWF1 depletion activated transcription of YAP target genes and induced cell cycle and proliferation in myoblasts. Furthermore, TWF1 knockdown markedly reduced the expressions of myogenic regulatory factors, such as MyoD and MyoG, and drastically hindered myoblast differentiation, fusion, and myotube formation. Collectively, this study highlights the essential role of TWF1 in the myogenic differentiation of progenitor cells via modulation of F-actin and YAP, and suggests TWF1 as a potential therapeutic target for muscle wasting and myopathies.

Impact of Chronic Kidney Disease Under Nephrology Care on Outcomes of Carotid Endarterectomy.

OBJECTIVE: This study aimed to investigate the impact of chronic kidney disease (CKD) and the delivery of nephrology care on outcomes of carotid endarterectomy (CEA). METHODS: This was a single centre, retrospective observational study. Between January 2007 and December 2014, 675 CEAs performed on 613 patients were stratified by pre-operative estimated glomerular filtration rate (eGFR) values (CKD [eGFR < 60 mL/min/1.73m2] and non-CKD [eGFR ≥ 60 mL/min/1.73m2] groups) for retrospective analysis. The study outcomes included the occurrence of major adverse cardiovascular events (MACEs), defined as fatal or non-fatal stroke, myocardial infarction, or all cause mortality, during the peri-operative period and within four years after CEA. RESULTS: The CKD group consisted of 112 CEAs (16.6%), and the non-CKD group consisted of 563 CEAs (83.4%). The MACE incidence was higher among patients with CKD compared with non-CKD patients during the peri-operative period (4.5% vs. 1.8%; p = .086) and within four years after CEA (17.9% vs. 11.5%; p = .066), with a non-statistically significant trend. In a subgroup analysis of patients with CKD under nephrology care (63/112, 56.3%; with better controlled risk factors and tighter medical surveillance by a nephrologist), patients with CKD without nephrology care (49/112, 43.8%), and non-CKD patients, the risk of both peri-operative (4.1% vs. 0.4%; p = .037) and four year post-operative (20.4% vs. 7.3%; p = .004) all cause mortality was statistically significantly higher among patients with CKD without nephrology care compared with non-CKD patients. However, there were no statistically significant differences between patients with CKD who received nephrology care and non-CKD patients in peri-operative and four year post-operative MACE occurrence, both in terms of the composite MACE outcome and the individual MACE components. CONCLUSION: Despite the higher risk of peri-operative and four year MACE after CEA among patients with CKD, and the statistically significantly higher peri-operative and four year post-operative all cause mortality rates among patients with CKD without nephrology care, patients with CKD under nephrology care had similar outcomes to non-CKD patients.

Effectiveness of Surgical Treatment with Complete Cyst Excision for Cystic Adventitial Disease of the Popliteal Artery.

BACKGROUND: Cystic adventitial disease is a rare, nonatherosclerotic disease that affects various arteries and veins, involving the formation of a mucinous cyst within the adventitia. The etiology of the cystic adventitial disease is currently unclear, with several hypotheses having been suggested. The purpose of this retrospective observational study was to evaluate the etiology of popliteal cystic adventitial disease based on imaging and surgical findings and to evaluate the efficacy of surgical treatment. METHODS: From April 2013 to January 2020, nine patients were diagnosed with the popliteal cystic adventitial disease and underwent surgical treatment. We performed complete resection of the cyst and the affected segment of the popliteal artery, followed by interposition with autologous reversed small saphenous vein or great saphenous vein. RESULTS: The resected adventitial cyst tissue was multilobular, filled with high-viscosity mucus. Pathologic examination of the surgical specimen revealed intramural cysts filled with gelatinous material located between the media and the adventitia, consistent with the clinical diagnosis of cystic adventitial disease. The median follow-up period was 27.5 months (range: 2-91 months). All patients underwent cyst excision with graft interposition, and the overall graft patency was 80.9 months (95% CI: 62.2-99.6 months). CONCLUSIONS: Computed tomography, magnetic resonance imaging, and surgical findings confirmed communication between the synovial cyst and arterial adventitia. It is recommended that priority be given to surgical resection and graft interposition because this can eliminate the disease's cause and reduce its recurrence.

Risk Factors for Early and Late Type Ib Endoleak Following Endovascular Abdominal Aortic Aneurysm Repair.

OBJECTIVES: A type Ib endoleak (T1bEL) is a postoperative complication that usually requires additional interventions following endovascular aortic aneurysm repair. Previous studies have focused on iliac artery tortuosity or common iliac artery (CIA) diameter. However, we investigated the various risk factors for early and late T1bELs more comprehensively. METHODS: This retrospective case-control study of a prospectively maintained database compared anatomical, demographic and technical factors between patients with early or late T1bELs and a control group. Early T1bEL was defined as a T1bEL occurring within 6 months of endovascular aneurysm repair (EVAR), while late T1bEL was defined as a T1bEL, initially identified more than 6 months after EVAR. Anatomical values including neck diameter, length, and angle; maximum sac diameter and length; CIA length, diameter, and tortuosity; and distal sealing length were measured and included in the analysis. We performed uni- and multivariable analyses using logistic regression and Cox proportional hazard models. RESULTS: This study included 635 iliac limbs of 383 patients. Overall, T1bELs occurred in 22 iliac limbs during the follow-up period (22/635, 3.5%). Among them, the early and late T1bEL groups each included 11 limbs. The median follow-up duration of the 383 patients was 23 (8-58) months, and in the early T1bEL and early control groups, the durations were 15 (9-35) and 29 (15-60) months, respectively (P = 0.01). The median overall follow-up durations in the late T1bEL and late control groups were 87 (76-102) and 62 (48-80) months, respectively (P = 0.01). The median follow-up duration until the occurrence of late T1bEL was 44 (32-82) months, which was shorter than that of the late control group (P = 0.03). No significant differences in sex, age, or brand of stent-graft were observed between the T1bEL and control groups. In the multivariable analysis, patients in the early T1bEL group had significantly more tortuous and short CIAs, and short distal sealing lengths (P = 0.02, P = 0.04, P = 0.03, respectively), and the late T1bEL group had significantly larger maximum aortic aneurysm sac diameters, short CIAs and short distal sealing lengths (P < 0.001, P = 0.02, P = 0.002, respectively). The suspected mechanisms of the T1bELs were CIA dilatation with or without sac expansion and aggravation of sac angulation. Except for one patient with aortic dissection, T1bELs were treated with iliac limb extensions. CONCLUSIONS: The various mechanisms of T1bELs differed depending on the time of onset from the procedure. An extensive sealing length may be protective against T1bEL, especially when the size of the aortic aneurysm sac is large or when the CIA has risky features, including large diameter or short length. Careful preoperative consideration of aortic aneurysm size and CIA length and tortuosity is essential, and patients with risky features should undergo strict postoperative surveillance.

Risk Factors for Early and Late Iliac Limb Occlusions of Stent Grafts Extending to the External Iliac Artery after Endovascular Abdominal Aneurysm Repair.

BACKGROUND: Iliac limb stent grafting to the external iliac artery (EIA) is a commonly performed procedure in various situation during endovascular abdominal aneurysm repair (EVAR). However, this procedure is associated with a risk of graft occlusion. We evaluated risk factors affecting occlusion among patients who underwent iliac limb stent-graft extension to the EIA. MATERIALS AND METHODS: We compared occluded limbs with patent limbs during the follow-up period using variables, including anatomical values, demographics, and other factors. Thereafter, we divided the occluded limbs into early and late occlusion subgroups. The main and subgroup analyses used the same variables. Survival analysis was performed to evaluate time-dependent risk factors for late limb occlusion. RESULTS: From 2007 to 2016, 766 iliac limbs from 383 patients who underwent EVAR were initially included in our analysis. Among them, 134 iliac limbs underwent limb extension to the EIA. The limb extension was a significant risk factor for occlusion (hazard ratio = 6.34, P < 0.001). Occlusion occurred in 10 patients who underwent iliac limb extension. The size of common iliac artery (CIA) was associated with occlusion. The most significant factor was iliac bifurcation diameter (patent vs. occluded limbs, 21.6 ± 7.6 vs. 27.5 ± 9.5 mm, P = 0.005). Subgroup analysis revealed that the CIAs of the early occlusion subgroup were generally more tortuous (1.16 ± 0.33 vs. 1.47 ± 0.25, P = 0.091) and longer (53 ± 24 vs. 74 ± 9, P = 0.01) than those of the patent limb group. In addition, the EIA diameters of the late occlusion subgroup were narrower than those of the patent limb group (10.9 ± 1.6 mm vs. 9.1 ± 0.8 mm, P = 0.011). Using the log-rank test, those patients with an EIA diameter narrower than 10.1 mm had a higher risk for late limb occlusion (log-rank χ2 = 5.73, P = 0.017) and the patients who did not take at least a single antiplatelet agent had a significantly higher chance of limb occlusion (log-rank χ2 = 11.029, P = 0.001). In addition, the patients who did not take a statin had a higher risk for late limb occlusion (log-rank χ2 = 7.41, P = 0.007). CONCLUSIONS: Among patients who underwent EVAR with iliac limb extension, the CIA length affected early limb occlusion and predisposed patients to vessel injury or stent-graft kinking, and there was the possibility that CIA tortuosity was associated with a higher risk. The late occlusion subgroup had narrower EIAs than the patent limb group. Appropriate antiplatelet and statin therapy is expected to play a key role in the prevention of late limb occlusion after EVAR.

Surgical Repair of Juxtarenal Abdominal Aortic Aneurysms and safety of Suprarenal Aortic Clamping.

BACKGROUND: Juxtarenal abdominal aortic aneurysm (AAA) comprises 15-20% of all AAAs and often requires open surgical repair (OSR) due to anatomical limitations associated with endovascular aneurysm repair (EVAR), particularly in the case of hostile proximal necks. This study aimed to evaluate short- and long-term outcomes of suprarenal clamping during OSR of juxtarenal AAAs and compare the outcomes of this technique with those of infrarenal clamping for AAAs. METHODS: Between January 1 2014, and December 31 2016, 289 consecutive patients aged ≥40 years underwent primary repair for infrarenal AAAs, including 141 OSRs and 148 EVARs. Of the 141 patients, 20 were excluded and totally, 121 patients were included. RESULTS: All patients had fusiform-type AAAs and were divided into infrarenal (N = 98) or suprarenal (N=23) clamp groups. The mean follow-up period was 51.4 months (95% CI: 48.6-54.2). Mean survival time was 51.4 months (95% CI: 48.6-54.2). Thirty-day mortality was 0.8%, and there was no significant difference between two groups (P > .999). Renal complication in infrarenal clamp group was 4.1% and suprarenal clamp group was 4.3% (P > .999). Old age (HR: 1.084; 95% CI: 1.025-1.147; P=.005) and high ASA score (HR: 2.361; 95% CI: 1.225-4.553; P = .010) were substantially associated with in-hospital complications. CONCLUSIONS: Although endovascular procedures for repairing juxtarenal AAAs, such as fenestrated EVAR, have been developed, surgical repair is the standard treatment for juxtarenal AAAs. Morbidity and mortality due to open surgery were not higher in the juxtarenal AAA group than in the infrarenal AAA group. Therefore, need for suprarenal clamp should not preclude OSR and also there is continued need for training in surgical exposure of juxtarenal AAA and OSR.

Outcomes of arteriovenous access among cancer patients requiring chronic haemodialysis.

BACKGROUND: There are limited data focusing specifically on the types of arteriovenous (AV) access used and outcomes of AV access among cancer patients as a consequence of cancer. We aimed to describe outcomes of AV access among cancer patients requiring chronic haemodialysis, and also to compare outcomes between patients with and without cancer. METHODS: In this single-centre, retrospective, observational cohort study, 84 patients diagnosed with cancer before AV access placement were included; we analysed outcomes of AV access among these patients and compared these outcomes with our previous results. The study endpoints were AV access patency and early failure, defined as AV access abandonment within 12 months after AV access placement. RESULTS: Various cancer types, stages, and treatments were identified in our analysis. Autologous arteriovenous fistulas (AVFs) were used for 92.9% of this study population. Using our previous results for comparison, we found no significant difference in death-censored primary (P = 0.546) and secondary (P = 0.266) patency of AV access between patients with and without cancer; however, the rate of early AVF failure was statistically significantly higher among cancer patients (25.6% vs 13.9%; P = 0.008), and the most common cause of AVF failure was patient death. The rate of early failure was significantly higher among patients with advanced-stage cancer (59.1%) than among those with early-stage cancer (12.9%) (P <  0.001). CONCLUSIONS: Although AV access patency rates were similar among patients with and without cancer in the death-censored analysis, cancer patients were more prone to early AVF failure, mainly due to cancer-associated deaths, and this consideration needs to be carefully balanced against individual patients' life expectancies, according to cancer type and stage.

Obturator bypass using a ringed polytetrafluoroethylene graft for inguinal graft infection.

OBJECTIVE: Inguinal vascular graft infections are high-risk events that cannot be controlled medically but require surgical intervention. This study reviewed the long-term clinical outcomes of obturator bypass using a ringed polytetrafluoroethylene graft for inguinal graft infection. METHODS: A total of eight consecutive patients who underwent obturator bypass using a ringed polytetrafluoroethylene graft for inguinal prosthetic graft infection at a single medical center between January 2006 and October 2017 were retrospectively analyzed. The demographics, clinical characteristics, surgical procedure, and clinical outcomes were evaluated. RESULTS: There was no perioperative death; however, there were three operative complications. On the 1st and 9th postoperative day, two patients underwent hematoma evacuation in the pelvic cavity, and the other patient underwent suture reinforcement for partial dehiscence of the distal anastomosis on the 49th postoperative day. The median length of hospital stay was 14.5 (range, 7-29) days. Only one graft occlusion was observed at postoperative month 40; however, there were no ischemic symptoms. There were no limb amputations and postoperative deaths during the long-term follow-up period. There were no infections of the previous residual and obturator bypass grafts and inguinal infection during the follow-up period of 49 (range, 7-154) months. CONCLUSION: Obturator bypass for inguinal graft infection is feasible and durable with excellent long-term outcomes. However, perioperative bleeding should be taken into consideration.

Relationship of Lower-extremity Deep Venous Thrombosis Density at CT Venography to Acute Pulmonary Embolism and the Risk of Postthrombotic Syndrome.

Background Acute deep venous thrombi (DVT) have higher Hounsfield unit values than chronic (bland) thrombi at CT venography. Purpose To determine the relationship between DVT thrombus density found on CT venography images to the presence of acute pulmonary embolism (PE) and the future risk of postthrombotic syndrome (PTS) in patients with DVT. Materials and Methods In this retrospective study, patients were divided into two groups: PE with DVT group and DVT-only group. Wells scores were recorded. Thrombus density ratios were calculated (DVT thrombus Hounsfield units/surrounding vein Hounsfield units). The presence or absence of PTS was determined from the results of the Venous Insufficiency Epidemiologic and Economic Study on Quality of Life (VEINES-QOL) questionnaires given to the patients with DVT. Statistical analyses used receiver operating characteristic curves and Spearman correlation analyses. Results Eighty-six patients were included; the mean age was 60 years ± 17 (51 men; PE with DVT group, 54 patients [63%]; DVT-only group, 32 patients [37%]). The mean thrombus density ratio was significantly higher in the PE with DVT group than in the DVT-only group (53.6% ± 12.4 [standard deviation] vs 42.8% ± 11.9, respectively; P < .001). At multivariable analysis, Wells score greater than 4 (odds ratio, 12.0; 95% confidence interval [CI]: 3.0, 47; P < .001) and higher thrombus density ratio (odds ratio, 1.1; 95% CI: 1.0, 1.2; P = .001) were independent predictors of PE. The diagnostic performance for the thrombus density ratio (area under the receiver operating characteristic curve, 0.74; 95% CI: 0.63, 0.85; P < .001) may be more discriminative than that of the Wells score (area under the receiver operating characteristic curve, 0.70; 95% CI: 0.59, 0.81; P = .002) for the presence of PE. In subgroup analysis, the thrombus density ratio and VEINES-QOL score were correlated (r = 0.61; 95% CI: 0.30, 0.80; P < .001). Conclusion Deep venous thrombosis (DVT) density ratio at CT venography was associated with acute pulmonary embolism in patients with lower-extremity DVT. © RSNA, 2019 Online supplemental material is available for this article.

Comparison of outcomes after carotid endarterectomy between type 2 diabetic and non-diabetic patients with significant carotid stenosis.

BACKGROUND: We aimed to compare early and late outcomes after carotid endarterectomy (CEA) between Korean type 2 diabetic and non-diabetic patients and to investigate the impact of diabetes on the overall incidence of cardiovascular events after CEA. METHODS: We retrospectively analyzed 675 CEAs, which were performed on 613 patients with significant carotid stenosis between January 2007 and December 2014. The CEAs were divided into a type 2 diabetes mellitus (DM) group (n = 265, 39.3%) and a non-DM group (n = 410, 60.7%). The study outcomes included the incidence of major adverse events (MAEs), defined as fatal or nonfatal stroke or myocardial infarction or all-cause mortality, during the perioperative period and within 4 years after CEA. RESULTS: Patients in the DM and non-DM groups did not differ significantly in the incidence of MAEs or any of the individual MAE manifestations during the perioperative period. However, within 4 years after CEA, the difference in the MAE incidence was significantly greater in the DM group (P = 0.040). Analysis of the individual MAE manifestations indicated a significantly higher risk of stroke in the DM group (P = 0.006). Multivariate analysis indicated that diabetes was not associated with MAEs or individual MAE manifestations during the perioperative period, whereas within 4 years after CEA, diabetes was an independent risk factor for MAEs overall (hazard ratio [HR], 1.62; 95% confidence interval [CI] 1.06-2.48; P = 0.026) and stroke (HR, 2.55; 95% CI 1.20-5.41; P = 0.015) in particular. CONCLUSIONS: Diabetic patients were not at greater risk of perioperative MAEs after CEA; however, the risk of late MAE occurrence was significantly greater in these patients. Within 4 years after CEA, DM was an independent risk factor for the occurrence of MAEs overall and stroke in particular.

New predictors of aneurysm sac behavior after endovascular aortic aneurysm repair.

OBJECTIVES: This study aimed to identify new predictors of sac behavior after endovascular aortic aneurysm repair (EVAR) and to investigate whether sac behavior is associated with long-term clinical outcomes. METHODS: A total of 168 patients undergoing successful EVAR for abdominal aortic aneurysms with CTA follow-up of at least 1 year were included. Predictors of aneurysm sac behavior and its impact on long-term clinical outcomes were retrospectively analyzed. RESULTS: According to sac behavior, eligible patients were stratified into the sac regression group (n = 79, 47.0%) and the sac non-regression group (n = 89, 53.0%). Patients in the regression group were younger (p = 0.036) and more likely to take sarpogrelate hydrochloride postoperatively (p = 0.011) than those in the non-regression group. The incidence of postimplantation syndrome (PIS) was significantly higher in the regression group (p = 0.005). On multivariate analysis, sac regression was more likely to occur in those with PIS (hazard ratio [HR], 1.68; 95% confidence interval [CI], 1.07-2.64; p = 0.023) and less likely to occur in those with transient type II endoleaks (HR, 0.43; 95% CI, 0.20-0.95; p = 0.037) and higher thrombus density within the sac on follow-up CTA (HR, 0.97; 95% CI, 0.95-0.99; p = 0.013). Non-regression of the sac was associated with significantly higher rates of re-intervention during the follow-up period (p = 0.001). CONCLUSIONS: In addition to type II endoleaks, PIS and thrombus density are new predictors of aneurysm sac behavior, and sac regression is significantly associated with lower rates of re-intervention. KEY POINTS: • After endovascular aortic aneurysm repair (EVAR), patients with sac regression were younger and more likely to take sarpogrelate hydrochloride postoperatively than those with sac non-regression. • The incidence of postimplantation syndrome (PIS) was significantly higher in patients with sac regression. • In our analysis, PIS and thrombus density within the sac were newly identified predictors of aneurysm sac behavior after EVAR.

Clinical Outcomes of Surgical Resection for Leiomyosarcoma of the Inferior Vena Cava.

BACKGROUND: Leiomyosarcoma of the inferior vena cava (IVC) is a rare mesenchymal tumor with poor prognosis. Surgical resection is currently the only potential curative treatment. This study analyzed long-term outcomes of patients who underwent surgical resection of leiomyosarcoma of the IVC. METHODS: The charts of 12 patients who underwent surgical resection of leiomyosarcoma of the IVC from January 1999 to December 2017 at a single center were retrospectively reviewed. RESULTS: Of the 12 patients, 10 (83.3%) were women. Median age at diagnosis was 63 years (range 42-67). Leiomyosarcoma involved the middle segment of the IVC in 9 patients (75.5%) and the lower segment in 3 (25.0%). Ten patients underwent IVC resection, followed by reconstruction with polytetrafluoroethylene in 9 patients and a bovine patch in 1. Two patients underwent IVC resection followed by ligation of the IVC. Eleven patients (91.7%) underwent grossly radical resection, with 1 (8.3%) having peritoneal seeding at the first operation. After resection, 8 patients received adjuvant chemotherapy and 7 received adjuvant radiotherapy. No patient experienced regional recurrence at the resection margins of the IVC, but 9 patients (75.5%) experienced distant metastases to sites such as the lungs, liver, bones, pelvis, peritoneum, and scalp. Median follow-up was 41 months (range 6-149). Median disease-free survival (DFS) was 49 months (range 8-88), and median overall survival (OS) was 127 months (range 25-149). The 3- and 5-year DFS rates were 77.9% and 39.0%, respectively, and the 3-, 5-, and 10-year OS rates were 87.5%, 75.0%, and 56.3%, respectively. CONCLUSIONS: Although there is no established treatment for leiomyosarcoma of the IVC and metastasis after surgery is frequent, surgical resection followed by chemotherapy and/or radiotherapy can enhance long-term survival.

Effects of patient age on patency of chronic hemodialysis vascular access.

BACKGROUND: In this single-center, retrospective observational study, we assessed the long-term patency of vascular access (VA) after first VA placement to uncover independent risk factors associated with VA patency in Asian hemodialysis (HD) patients stratified by age. We also investigated factors associated with VA patency among older HD patients according to the type of VA in the overall study population. METHODS: The study period was from January 2011 to December 2013. A total of 651 chronic HD patients with confirmed first upper-extremity VA placement were enrolled, and their records were analyzed retrospectively. A total of 445 patients (68.4%) made up the nonelderly group (< 65 years), and 206 patients (31.6%) were in the elderly group (≥ 65 years). Study outcomes were defined as primary or secondary VA patency. RESULTS: Autologous arteriovenous fistula (AVF) was more common in the nonelderly group (P <  0.01). Kaplan-Meier curve survival analysis indicated that primary patency was longer in the nonelderly group (P <  0.01); secondary patency, however, was similar between groups (P = 0.37). The multivariate analysis of factors associated with primary VA patency revealed that increased age (hazard ratio [HR], 1.02; 95% confidence interval [CI], 1.01-1.03; P <  0.01) was associated with shorter primary patency, and AVF (HR, 0.38; 95% CI, 0.28-0.51; P <  0.01) was associated with longer primary patency. AVF (HR, 0.57; 95% CI, 0.37-0.87; P = 0.010) and diabetes mellitus (HR, 1.56; 95% CI, 1.07-2.29; P = 0.02) were independently associated with longer and shorter secondary patency periods, respectively; however, increased age was not a risk factor for decreased secondary patency. CONCLUSIONS: Increased age was associated with shorter primary patency but not secondary patency, whereas AVF placement was associated with longer primary and secondary patency. Considering the similar rates of secondary patency between groups and the superior patency of AVF compared to arteriovenous graft, a fistula-first strategy should be applied to appropriate older patients.

Quantitative analysis of the effect of end-tidal carbon dioxide on regional cerebral oxygen saturation in patients undergoing carotid endarterectomy under general anaesthesia.

AIMS: Regional cerebral oxygen saturation (rSO2 ) is currently the most used measure in clinical practice to monitor cerebral ischaemia in patients undergoing carotid endarterectomy (CEA). Although end-tidal carbon dioxide (PET CO2 ) is known as a factor that influences rSO2 , the relationship between PET CO2 and rSO2 has not been quantitatively evaluated in patients with severe arteriosclerosis. This study aimed to evaluate the effect of PET CO2 on rSO2 in patients undergoing CEA under general anaesthesia. METHODS: The intervention to change PET CO2 was conducted between skin incision and clamping of the carotid artery. The rSO2 values were observed by changing PET CO2 in the range of 25-45 mmHg. The PET CO2 -rSO2 relationship was characterized by population analysis using a turnover model. RESULTS: In total, 1651 rSO2 data points from 30 patients were used to determine the pharmacodynamic characteristics. Hypertension (HTN) and systolic blood pressure (SBP) were significant covariates on the slope factor in the stimulatory effect of PET CO2 on rSO2 and fractional turnover rate constant (kout ), respectively. The estimates of the parameters were kout (min-1 ): 3.59 for SBP <90 mmHg and 0.491 for SBP ≥90 mmHg, slope: 0.00321 for patients with HTN and 0.00664 for patients without HTN. CONCLUSION: The presence of HTNattenuates the response of rSO2 after a change in PET CO2 . When cerebral blood flow is in a state of decline caused by a decrease in SBP to <90 mmHg, the response of rSO2 to PET CO2 is increased. It is advisable to maintain SBP >90 mmHg in patients with HTNduring CEA.

Clinical Outcomes of Conservative Treatment in Patients with Symptomatic Isolated Spontaneous Renal Artery Dissection and Comparison with Superior Mesenteric Artery Dissection.

OBJECTIVES: The aims of this study were to report the clinical outcomes of conservative medical treatment in patients with symptomatic isolated spontaneous renal artery dissection (SRAD) and compare them with those of spontaneous superior mesenteric artery dissection (SSMAD). METHODS: This was a single centre, observational comparative study between SRAD and SSMAD. Data from a prospective visceral artery dissection registry were analysed retrospectively. Between June 2010 and December 2016, 23 consecutive patients with symptomatic isolated SRAD who initially received conservative medical treatment were included. The primary outcomes were the aggravation of dissection requiring intervention and dissection related mortality. To evaluate the prognosis of symptomatic isolated SRAD, the clinical outcomes of isolated SRAD were compared with those of symptomatic isolated SSMAD (n = 40) during the same study period. RESULTS: The primary outcome incidence was 39% (9/23) in patients with symptomatic isolated SRAD during the median follow up period of 20 months (range 0-63 months). The dissection related mortality rate was 17% (4/23), and the cause of death in all cases was an abrupt rupture of the dissecting aneurysm with significant true lumen stenosis. None of the patients without aneurysm or with true lumen occlusion had dissection related mortality. During the same study period, compared with the patients with symptomatic isolated SSMAD who initially received conservative medical treatment, the primary outcome incidence (39% vs. 10%, p = .009) and dissection related mortality rate (17% vs. 0%, p = .016) were statistically significantly higher in patients with symptomatic isolated SRAD. CONCLUSIONS: Although the present analysis involved only a small number of patients, it revealed that symptomatic isolated SRAD with dissection related aneurysm and true lumen stenosis is a potentially life threatening condition and that aggressive surgical or endovascular interventions should be considered in these patients, who are refractory to conservative medical treatment.

Effect of systemic immunosuppressive drugs on the patency of hemodialysis accesses
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AIM: Intimal hyperplasia remains the leading cause of late hemodialysis access stenosis or occlusion. This study assessed the influence of conventional immunosuppressive drugs on the patency of hemodialysis accesses in patients with a history of organ transplantation. MATERIALS AND METHODS: Between January 2002 and December 2007, 1,654 patients underwent an operation for hemodialysis access. 135 patients received immunosuppressive therapy (IT); of these, 115 underwent an operation for hemodialysis access after transplanted graft failure and 20 patients after liver transplantation. The 5-year primary patency rates of hemodialysis access were compared twice between the entire study population and the matched cohorts using a 1 : 4 propensity score. RESULTS: A total of 82.2% of the nontransplanted (NT) patients and 71.9% of the IT patients had arteriovenous fistulas (AVFs). The 5-year primary patency rate was 74.0% for the NT group and 51.5% for the IT group (p < 0.001). The characteristics of the matched cohorts (135 IT patients and 536 NT patients) were well balanced; the 5-year primary patency rates were 70.0% and 54.9% for the NT and IT groups, respectively (p = 0.030). A significant impact of IT on primary patency was not observed in the matched cohort (hazard ratio, 0.930; 95% confidence interval, 0.706 - 0.226; p = 0.608). CONCLUSION: Systemic administration of immunosuppressive drugs did not significantly affect the patency of AVF or arteriovenous graft (AVG) access in the present study.
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The Results of In Situ Prosthetic Graft Replacement for Infected Aortic Disease.

BACKGROUND: Infected aortic disease is a serious clinical condition associated with significant morbidity and mortality. This study reviewed the outcomes of in situ aortic replacement with a prosthetic graft for infected aortic disease, including primary infected abdominal aortic aneurysms (PIAAA), infected aortic prosthetic grafts (IAPG), and infected aortic stent grafts (IASG). METHODS: Twenty-eight consecutive patients who underwent in situ aortic replacement with a prosthetic graft for PIAAA, IAPG, and IASG at a single center from January 2001 to December 2015 were retrospectively analyzed. Demographics, clinical characteristics, medical management, surgical procedure, and clinical outcomes were included. RESULTS: Nineteen patients with a PIAAA, three with an IAPG following open repair of abdominal aortic aneurysm (AAA), and six with an IASG following endovascular aortic repair underwent in situ prosthetic graft replacement with infected tissue and graft removal. In-hospital mortality was 7.1% (2/28). One died of bleeding on postoperative day 12, and the other died of hepatic failure on postoperative day 32. Of six patients with an IASG, two had major complications that were related to barb injury at the proximal aorta. The reinfection rate was 14.3% (4 of 28) during a mean follow-up of 35.7 months (1-142 months). All new grafts of three patients with IAPG were reinfected. The other patient became reinfected after surgery for PIAAA with iatrogenic small bowel perforation that was not detected during surgery. CONCLUSIONS: In situ graft replacement of PIAAA and IASG is feasible with acceptable outcomes, but the outcome for IAPG is questionable.

Early and Late Outcomes of Endovascular Aortic Aneurysm Repair versus Open Surgical Repair of an Abdominal Aortic Aneurysm: A Single-Center Study.

BACKGROUND: The objective of the study was to compare the treatment outcomes and cost of endovascular aortic aneurysm repair (EVAR) and open surgical repair (OSR) in patients with an abdominal aortic aneurysm (AAA) at a single center. METHODS: Patients treated for an AAA at a single center between January 2007 and December 2012 were retrospectively identified and classified based on the treatment they received (EVAR or OSR). Patient demographics and in-hospital costs were recorded. Long-term survival was calculated using the Kaplan-Meier method. RESULTS: During the study period, 401 patients with AAA were treated at Asan Medical Center. Among these cases, 226 were treated with EVAR (56%) and 175 received OSR (44%). The mean age of the EVAR group was higher than that of the OSR group (71.25 ± 7.026 vs. 61.26 ± 8.175, P < 0.001). The need for intraoperative transfusion and total length of in-hospital stay were significantly lower in the EVAR group (P < 0.001). The OSR group showed significantly reduced rates of overall mortality (P = 0.003), overall reintervention (P = 0.001), and long-term survival (63.98 ± 1.86 vs. 99.54 ± 3.17, P < 0.001). The OSR group was charged significantly less than the EVAR group ($12,879.21 USD vs. $18,057.78 USD, P < 0.001). CONCLUSIONS: EVAR has advantages over OSR in terms of short-term mortality, in-hospital length of stay, and rates of perioperative transfusion. However, OSR is associated with better long-term survival, lower reintervention rates, and lower costs.

Chronic Nonatherosclerotic Occlusive Popliteal Artery Disease.

BACKGROUND: The outcomes of revascularization of nonatherosclerotic occlusive popliteal artery disease are unknown. Therefore, the objective of this study was to analyze the outcomes of recanalization of nonatherosclerotic occlusive popliteal artery disease, the results of which would be useful in creating surgical strategies for such cases. METHODS: From January 2000 to December 2015, a total of 22 patients with nonatherosclerotic occlusive popliteal artery disease underwent open surgical repair. We retrospectively analyzed the data of these patients. Thrombectomy with angioplasty on the occluded popliteal artery, graft interposition, and bypass surgery were conducted for revascularization of the affected region. We analyzed the overall primary patency rate, type of graft, and surgical approach. Furthermore, we compared the primary patency rate after surgical treatment. RESULTS: Of 22 patients, 3 (13.6%) had cystic adventitial disease, 16 (72.7%) had popliteal artery entrapment syndrome, and 3 (13.6%) were diagnosed as having thromboangiitis obliterans. Five patients (22.7%) underwent thrombectomy with patch angioplasty, 8 (36.3%) underwent bypass surgery, and 9 (40.9%) underwent graft interposition of the popliteal artery. All graft interpositions and thrombectomies with patch angioplasty were performed through a posterior approach, whereas all bypass surgeries were performed through a medial approach except in 1 case. The mean follow-up period was 54.95 ± 42.99 months. The overall primary patency rate at 1, 3, and 10 years was 100%, 86.9%, and 69.5%, respectively. In the bypass group, the primary patency rate at 1, 3, and 10 years was 100%, 66.7%, and 44.4%, respectively. In the other groups, the primary patency rate was 100% during the follow-up period. The difference in primary patency rate was statistically significant (P ≤ 0.05). CONCLUSIONS: The result of surgical treatment for nonatherosclerotic occlusive popliteal artery disease was better than that of atherosclerotic popliteal artery disease. Direct popliteal artery reconstruction, such as graft interposition or thrombectomy with patch angioplasty, showed better short- and long-term patency than did bypass surgery.