Hyung Jik Kim

Obesity-related decrease in intraoperative blood flow is associated with maturation failure of radiocephalic arteriovenous fistula

OBJECTIVEnSuccessful arteriovenous fistula (AVF) maturation is often challenging in obese patients. Optimal initial intraoperative blood flow (IOBF) is essential for adequate AVF maturation. This study was conducted to elucidate the effect of obesity on IOBF and radiocephalic AVF maturation.nnnMETHODSnPatients with a newly created radiocephalic AVF were included (N = 252). Obesity was defined as a baseline body mass index (BMI) ≥25 kg/m(2), and primary maturation failure was defined as failure to use the AVF successfully by 3 months after its creation. IOBF was measured immediately after construction of the AVF with a VeriQ system (MediStim, Oslo, Norway).nnnRESULTSnThe mean BMI was 24.1 ± 3.9 kg/m(2), and the prevalence of obesity was 31.3%. Particularly, 8.3% (21 patients) had a BMI ≥30 kg/m(2). Primary maturation failure occurred in 100 patients (39.7%), and an IOBF <190 mL/min was closely associated with the risk of maturation failure (relative risk, 3.05; 95% confidence interval, 1.52-6.11). Compared with nonobese patients, obese subjects had a significantly higher prevalence of diabetes and elevated high-sensitivity C-reactive protein levels, whereas diameters of vessels were similar. When the patients were further divided into three groups as BMI <25, 25 to 29.9, and ≥30 kg/m(2), patients in the higher BMI group showed significantly lower IOBF and higher maturation failure rate. According to multivariate analysis, the statistically significant variables that determined maturation failure were obesity, previous vascular disease, increased high-sensitivity C-reactive protein levels, and IOBF <190 mL/min.nnnCONCLUSIONSnObese patients had a significantly lower IOBF, and both obesity and low IOBF contributed to the primary maturation failure of AVF. Obesity-associated inflammation and atherosclerosis might play roles in this association.

A Low Baseline Glomerular Filtration Rate Predicts Poor Clinical Outcome at 3 Months after Acute Ischemic Stroke

Background and Purpose Chronic kidney disease (CKD) is an established risk factor for numerous cardiovascular diseases including stroke. The relationship between the baseline estimated glomerular filtration rate (eGFR) and clinical 3-month outcomes in patients with acute ischemic stroke were evaluated in this study. Methods This was a prospective cohort study involving a hospital-based stroke registry; 1373 patients with acute ischemic stroke were enrolled. Patients were divided into the following four groups according their eGFR (calculated using the CKD Epidemiology Collaboration equations): ≥60, 45-59, 30-44, and <30 mL/min/1.73 m2. The primary endpoint of poor functional outcome was defined as 3-month death or dependency (modified Rankin Scale score ≥3); secondary endpoints were neurological deterioration (increase in National Institutes of Health Stroke Severity score of ≥4 at discharge compared to baseline) during hospitalization and in-hospital mortality. Results The overall eGFR was 84.5±20.8 mL/min/1.73 m2 (mean±SD). The distribution of baseline renal impairment was as follows: 1,218, 82, 40, and 33 patients had eGFRs of ≥60, 45-59, 30-44, and <30 mL/min/1.73 m2, respectively. At 3 months after the stroke, 476 (34.7%) patients exhibited poor functional outcome. Furthermore, a poor functional outcome occurred more frequently with increasingly advanced stages of CKD (rates of 31.9%, 53.7%, 55.0%, and 63.6% for CKD stages 1/2, 3a, 3b, and 4/5, respectively; p<0.001). Multivariate analysis revealed that a baseline eGFR of <30 mL/min/1.73m2 increased the risk of a poor functional outcome by 2.37-fold (p=0.047). In addition, baseline renal dysfunction was closely associated with neurological deterioration during hospitalization and with in-hospital mortality. Conclusions A low baseline eGFR was strongly predictive of both poor functional outcome at 3 months after ischemic stroke and neurological deterioration/mortality during hospitalization.

Therapeutic Plasma Exchange Using the Spectra Optia Cell Separator Compared With the COBE Spectra

Background The Spectra Optia (SPO) is a novel continuous-flow centrifugal apheresis system based on the COBE Spectra (CSP) platform. There have been few attempts to validate the advantages of the SPO. We performed a retrospective study comparing the two cell separators for therapeutic plasma exchange (TPE) procedures in kidney transplant (KT) patients and seeing efficacy and safety. Methods We analyzed 720 TPE procedures performed between August 2012 and July 2014. Procedures included desensitization TPE before KT and TPE for the management of acute and chronic antibody-mediated graft rejection. Demographic characteristics, operational TPE variables, and laboratory data were analyzed. Results Demographic characteristics for the SPO (n=389) and CSP (n=331) groups did not differ significantly. The procedure time to exchange one plasma volume was 94.2±10.3 min in the SPO group and 100.4±11.2 min in the CSP group (P<0.001). The plasma removal efficiency (PRE) was 92.5±4.9% in the SPO group and 83.2±3.7% in the CSP group (P<0.001). There were no significant differences across the two apheresis systems for changes in hematologic parameters. Conclusions Compared with the CSP, the SPO was associated with an improved PRE and a shorter procedure time to exchange one plasma volume. Our results in KT patients show that the SPO is superior to the CSP in TPE procedures.

High pulse pressure and metabolic syndrome are associated with proteinuria in young adult women

BackgroundObesity and metabolic syndrome play causative roles in the increasing prevalence of proteinuria in the general population. However, in young adult women the clinical significance of incidentally discovered proteinuria and its association with metabolic syndrome are unclear. We investigated the prevalence and risk factors for proteinuria in this population.MethodsA total of 10,385 women aged 20 to 39u2009years who underwent health screenings were surveyed. Each patient was tested for proteinuria with a dipstick (−, ±, 1+, 2+, or 3+), and proteinuria was defined as 1+ or greater. Persistent proteinuria was established by confirming proteinuria in a subsequent test. Metabolic syndrome was defined in accordance with the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asia.ResultsThe mean age was 28.9u2009±u20095.5u2009years, and the prevalence of persistent proteinuria was 1.0%. Among these subjects with persistent proteinuria, obesity and metabolic syndrome were found in 10.4% and 5.2%, respectively. Metabolic syndrome, as well as its components of hypertension, hyperglycemia, central obesity, low high-density lipoprotein levels, and high triglyceride levels, was closely related to the presence of proteinuria. In addition, a wide pulse pressure of ≥40u2009mmHg was another independent risk factor for proteinuria [odds ratio (OR) 3.29, 95% confidence interval (CI) 1.03–11.91)]. This had an additive effect on metabolic syndrome in terms of predicting proteinuria. Even in subjects without metabolic syndrome, the influence of an increased pulse pressure was consistent (OR 2.75, 95% CI 1.03–8.61).ConclusionsSpecific attention to proteinuria may be necessary in asymptomatic young women aged 20 to 39u2009years if they have metabolic syndrome or a wide pulse pressure.

Vitamin D: a possible modifying factor linking obesity to vascular calcification in hemodialysis patients

BackgroundObesity is a risk factor for increased cardiovascular disease. Whether vitamin D deficiency modifies this association is unclear. Here, we examined the association of obesity and vitamin D deficiency with vascular calcification score (VCS) in incident end-stage renal disease (ESRD) patients.MethodsA cross-sectional study was conducted with 213 ESRD patients. Vitamin D deficiency was defined as serum 25-hydroxyvitamin D (25(OH)D) levels below 10xa0ng/mL, and obesity was defined as a percentage of body fat (PBF) higher than the sex-specific median value in the cohort (>26.8% for men, >36.2% for women). VCS was measured by plain radiographic film of the lateral abdomen in the standing position.ResultsMost ESRD patients (76.6%) had 25(OH)D deficiency at the start of dialysis. The prevalence of 25(OH)D deficiency was much higher in obese patients than non-obese patients, and it had significant inverse association with PBF (ru2009=u2009−0.315, pu2009<u20090.001). Abdominal aortic calcification was identified in 104 (48.9%) patients. VCS was significantly higher in obese population; 2.6 (0–23) for all patients, 4.2 (0–23) for obese and 1.0 (0–12) for non-obese patients (pu2009<u20090.001). Interestingly, vitamin D deficiency was associated with greater risk of a high VCS, especially in obese population [odds ratio (OR) 3.02, 95% confidence interval (CI) 1.09-9.38)], but not with non-obese patients (OR 1.82, 95% CI 0.56-5.60).ConclusionThe magnitude and direction of the association between obesity and the risk of vascular calcification may depend on an individual’s 25(OH)D level, a possible representative marker of cardiometabolic disturbance in ESRD patients.

Impact of rapid ultrafiltration rate on changes in the echocardiographic left atrial volume index in patients undergoing haemodialysis: a longitudinal observational study

Objective Optimal fluid management is essential when caring for a patient on haemodialysis (HD). However, if the fluid removal is too rapid, the resultant higher ultrafiltration rate (UFR) disadvantageously promotes haemodynamic instability and cardiac injury. We evaluated the effects of a rapid UFR on changes in the echocardiographic left atrial volume index (LAVI) over a period of time. Design Longitudinal observational study. Setting and participants A total of 124 new patients on HD. Interventions Echocardiography was performed at baseline and repeated after 19.7u2005months (range 11.3–23.1u2005months). Changes in LAVI (ΔLAVI/year, mL/m2/year) were calculated. The UFR was expressed in mL/hour/kg, and we used the mean UFR over 30u2005days (∼12–13 treatments). Main outcome measures The 75th centile of the ΔLAVI/year distribution was regarded as a ‘pathological’ increment. Results The mean interdialytic weight gain was 1.73±0.94u2005kg, and the UFR was 8.01±3.87u2005mL/hour/kg. The significant pathological increment point in ΔLAVI/year was 4.89u2005mL/m2/year. Correlation analysis showed that ΔLAVI/year was closely related to the baseline blood pressure, haemoglobin level, residual renal function and UFR. According to the receiver operating characteristics curve, the ‘best’ cut-off value of UFR for predicting the pathological increment was 10u2005mL/hour/kg, with an area under the curve of 0.712. In multivariate analysis, systolic blood pressure, a history of coronary artery disease, haemoglobin <10u2005g/dL and high UFR were significant predictors. An increase of 1u2005mL/hour/kg in the UFR was associated with a 22% higher risk of a worsening LAVI (OR 1.22, 95% CI 1.05 to 1.41). Conclusions An increased haemodynamic load could affect left atrial remodelling in incident patients on HD. Thus, close monitoring and optimal control of UFR are needed.

Excessive Weight Gain during the First Year of Peritoneal Dialysis Is Associated with Inflammation, Diabetes Mellitus, and a Rapid Decrease in Residual Renal Function.

Objectives Significant weight gain is a potential problem in most patients starting peritoneal dialysis (PD); however, few studies have explored the clinical effects of increased body weight (BW) in these patients. We evaluated the effect of excess weight gain during the first year after PD on residual renal function (RRF). Methods A total of 148 incident PD patients were analyzed in a longitudinal observational study. The mean duration of follow-up was 23.8 months. RRF was measured at baseline (within 1 month of starting PD) and thereafter at 6-month intervals for 2–3 years or until loss of RRF. BW was measured at the time of RRF measurement, and excess weight gain was defined as a BW increase over the median value (3.0%). Results The median 1-year increase in BW was 2.3kg (IQR, 1.01–4.58) or 3.0% (IQR, 1.13–5.31). The mean slope of RRF decline was –0.068 ± 0.053 mL/min/month/1.73m2, and RRF loss developed in 48 patients at a mean follow-up time of 19.4 ± 6.8 months. Patients with BW increases > 3.0% showed significantly increased RRF decline rate compared to those without excess weight gain (p<0.001), and the BW increase (%/year) correlated significantly with higher hs-CRP levels and RRF decline rate. High systolic blood pressure, diabetes, large amount of proteinuria and excess BW gain significantly influenced the RRF decline rate. Also, it increased the risk of RRF loss by 4.17-fold (95% confidence intervals, 1.87–9.28; p<0.001). Conclusions Excess weight gain during the first year of PD was closely linked to systemic inflammation, diabetes and rapid decline in RRF.

Leptin, pre-existing vascular disease, and increased arteriovenous fistula maturation failure in dialysis patients

BACKGROUNDnThe adipocytokine leptin is an independent cardiovascular risk factor and exerts proatherogenic effect. Pre-existing vascular disease is an important cause of arteriovenous fistula (AVF) maturation failure. We explored the association between serum leptin, pre-existing vascular disease, and AVF maturation failure in incident hemodialysis patients.nnnMETHODSnVein samples from 62 patients were collected at the time of AVF creation. Pre-existing vascular disease was evaluated with histologic changes and immunohistochemical characteristics of cellular phenotypes in intima. AVF maturation failure was defined as an AVF that could not be used successfully by the third month after its creation.nnnRESULTSnThe prevalence of body mass index ≥30xa0kg/m2 was 17%, and AVF maturation failure occurred in 28 (45%) patients. Patients within the highest leptin tertile showed significantly higher maturation failure rate, independent of age, gender, diabetes, and body mass index. On histologic examination, significant differences in intimal hyperplasia (13.3xa0± 4.5 vs 18.2xa0± 5.2 vs 30.3xa0± 14.3xa0μm) and medial thickening (76.8xa0± 23.7 vs 103.9xa0± 33.6 vs 109.3xa0± 36.5xa0μm) were observed across leptin tertiles. Similarly, medial fibrosis was most severe in the highest tertile. According to the immunohistochemical staining, most intimal cells were α-smooth muscle actin-positive, vimentin-positive, desmin-negative myofibroblasts. However, in the lowest tertile, desmin-positive contractile smooth muscle cells were also frequently observed, suggesting relatively slow phenotypic changes in this group. Furthermore, as leptin tertiles increased, the expression of leptin receptor in the luminal border of intima was significantly decreased.nnnCONCLUSIONSnObesity-related higher fistula maturation failure rate may be partly mediated by higher leptin level-associated pre-existing vascular diseases in end-stage renal disease patients. Decreased expression of leptin receptor may be related to this association.

Anatomical variants of upper arm veins on preoperative mapping venography for hemodialysis access in Korean adults

Introduction: The number of elderly patients requiring hemodialysis has increased, along with the need for multiple vascular access placements. Thus, the frequency of access creation using the upper arm veins, including transposed basilic arteriovenous fistula, has also increased. The purpose of this study was to identify the prevalence of anatomical variations in the upper arm veins on preoperative mapping venography and to investigate the implications of such variants on access creation. Methods: A total of 494 venograms were performed on 251 patients for primary access creation from June 2014 to June 2017 in this single-center, retrospective study. The venograms were classified into eight subtypes, based on the anatomical relationship between the basilic and brachial veins. The presence of bifid cephalic arches and brachial–basilic ladders was also examined. Results: The presence of bifid cephalic arches and brachial–basilic ladders was identified in 8.7% and 14.0% of cases, respectively. Paired brachial veins joined separately with the basilic vein in 67.4% of venograms, whereas these veins merged into a common brachial vein before connecting to the basilic vein in 13.1% of cases. A single brachial vein was present in 19.3% of cases. 15.7% of cases were considered unsuitable for basilic vein transposition due to the early confluence of the brachial–basilic vein, posing a risk of obliterating the deep venous drainage if transposed. Conclusion: There are significant anatomical variations of upper arm veins, and the recognition of certain variants can affect surgical planning and outcomes of access placement. It is important to identify anatomical variants of the upper arm veins during preoperative vein mapping.

Four-Year Changes in Visceral Fat Mass and the Risk of Developing Proteinuria in the General Population

Background Previous cross-sectional studies demonstrated the close relationship between visceral obesity and the increased prevalence of proteinuria. But, little is known about the role of changes in visceral fat mass (∆VFM) over several years in the development of proteinuria. In this longitudinal cohort study with the general population, the changes in ∆VFM as well as baseline VFM on proteinuria development were evaluated. Methods Healthy individuals (n = 2393) who participated in two health screening exams were analyzed. Subjects were divided into three groups based on gender-specific tertiles of baseline VFM and ∆VFM. Each patient was tested for proteinuria using a dipstick, and proteinuria was defined as 1+ or greater. Results The mean age was 51.9±7.7 years, and the incidence of proteinuria was 3.9% (n = 93). During the 4 years, 52.5% of the subjects experienced a decline in ∆VFM. However, subjects who developed proteinuria exhibited a significant increase in ∆VFM. Even after adjustment for age, smoking, systolic and diastolic BP, serum creatinine, and hs-CRP levels, the highest tertiles for baseline VFM [men, odds ratio (OR) 3.43, 95% confidence interval (CI) 1.22–9.67; women, OR 2.01, 95% CI 1.05–4.15] and ∆VFM (men, OR 2.92, 95% CI 1.22–6.99; women, OR 3.16, 95% CI 1.56–6.39) were independent predictors of proteinuria development. Following adjustment of both parameters, subjects in the highest baseline VFM and ∆VFM tertiles exhibited the greatest risk of proteinuria development, which suggested the additive harmful effects of the two factors. Conclusions Baseline VFM and greater increase in ∆VFM were both important risk factors for developing proteinuria in the general population. Appropriate education and interventions to prevent accumulation of VFM should be the major focus of preemptive strategies.