Ha Yeon Kim

Incidence, predictive factors, and clinical outcomes of acute kidney injury after gastric surgery for gastric cancer.

Background Postoperative acute kidney injury (AKI), a serious surgical complication, is common after cardiac surgery; however, reports on AKI after noncardiac surgery are limited. We sought to determine the incidence and predictive factors of AKI after gastric surgery for gastric cancer and its effects on the clinical outcomes. Methods We conducted a retrospective study of 4718 patients with normal renal function who underwent partial or total gastrectomy for gastric cancer between June 2002 and December 2011. Postoperative AKI was defined by serum creatinine change, as per the Kidney Disease Improving Global Outcomes guideline. Results Of the 4718 patients, 679 (14.4%) developed AKI. Length of hospital stay, intensive care unit admission rates, and in-hospital mortality rate (3.5% versus 0.2%) were significantly higher in patients with AKI than in those without. AKI was also associated with requirement of renal replacement therapy. Multivariate analysis revealed that male gender; hypertension; chronic obstructive pulmonary disease; hypoalbuminemia (<4 g/dl); use of diuretics, vasopressors, and contrast agents; and packed red blood cell transfusion were independent predictors for AKI after gastric surgery. Postoperative AKI and vasopressor use entailed a high risk of 3-month mortality after multiple adjustments. Conclusions AKI was common after gastric surgery for gastric cancer and associated with adverse outcomes. We identified several factors associated with postoperative AKI; recognition of these predictive factors may help reduce the incidence of AKI after gastric surgery. Furthermore, postoperative AKI in patients with gastric cancer is an important risk factor for short-term mortality.

Relation of Serum Potassium Level to Long-Term Outcomes in Patients With Acute Myocardial Infarction

Potassium plays a key role in normal myocardial function, and current guidelines recommend that serum potassium levels be maintained from 4.0 to 5.0 mEq/L in patients with acute myocardial infarction (AMI). However, the impact of serum potassium levels on long-term mortality has not been evaluated. We retrospectively studied 1,924 patients diagnosed with AMI. The average serum potassium levels measured throughout the hospitalization were obtained and statistically analyzed. Patients were categorized into 5 groups to determine the relation between mean serum potassium and long-term mortality: <3.5, 3.5 to <4.0, 4.0 to <4.5, 4.5 to <5.0, and ≥5 mEq/L. The long-term mortality was lowest in the group of patients with potassium levels of 3.5 to <4.0 mEq/L, whereas mortality was higher in the patients with potassium levels≥4.5 or <3.5 mEq/L. In a multivariate Cox-proportional regression analysis, the mortality risk was greater for serum potassium levels of >4.5 mEq/L (hazard ratio [HR] 1.71, 95% confidence interval [CI] 1.04 to 2.81 and HR 4.78, 95% CI 2.14 to 10.69, for patients with potassium levels of 4.5 to <5.0 mEq/L and ≥5.0, respectively) compared with patients with potassium levels of 3.5 to <4.0 mEq/L. The mortality risk was also higher for patients with potassium levels<3.5 mEq/L (HR 1.55, 95% CI 0.94 to 2.56). In contrast to the association with long-term mortality, there was no relation between serum potassium levels and the occurrence of ventricular arrhythmias. The results of the current analysis suggest that there is a need for change in our current concepts of the ideal serum potassium levels in patients with AMI.

Association of Pulse Wave Velocity and Pulse Pressure With Decline in Kidney Function

The association between arterial stiffness and decline in kidney function in patients with mild to moderate chronic kidney disease (CKD) is not well established. This study investigated whether pulse wave velocity (PWV) and pulse pressure (PP) are independently associated with glomerular filtration rate (GFR) and rapid decline in kidney function in early CKD. Carotid femoral PWV (cfPWV), brachial‐ankle PWV (baPWV), and PP were measured in a cohort of 913 patients (mean age, 63±10 years; baseline estimated GFR, 84±18 mL/min/1.73 m2). Estimated GFR was measured at baseline and at follow‐up. The renal outcome examined was rapid decline in kidney function (estimated GFR loss, >3 mL/min/1.73 m2 per year). The median follow‐up duration was 3.2 years. Multivariable adjusted linear regression model indicated that arterial PWV (both cfPWV and baPWV) and PP increased as estimated GFR declined, but neither was associated with kidney function after adjustment for various covariates. Multivariable logistic regression analysis found that cfPWV and baPWV were not associated with rapid decline in kidney function (odds ratio [OR], 1.39, 95% confidence interval [CI], 0.41–4.65; OR, 2.51, 95% CI, 0.66–9.46, respectively), but PP was (OR, 1.22, 95% CI, 1.01–1.48; P=.045). Arterial stiffness assessed using cfPWV and baPWV was not correlated with lower estimated GFR and rapid decline in kidney function after adjustment for various confounders. Thus, PP is an independent risk factor for rapid decline in kidney function in populations with relatively preserved kidney function (estimated GFR ≥30 mL/min/1.73 m2).

Metabolic syndrome and chronic kidney disease in an adult Korean population: results from the Korean National Health Screening.

Background This study was aimed to examine the prevalence of metabolic syndrome (MS) and chronic kidney disease (CKD), and the association between MS and its components with CKD in Korea. Methods We excluded diabetes to appreciate the real impact of MS and performed a cross-sectional study using the general health screening data of 10,253,085 (48.86±13.83 years, men 56.18%) participants (age, ≥20 years) from the Korean National Health Screening 2011. CKD was defined as dipstick proteinuria ≥1 or an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2. Results The prevalence of CKD was 6.15% (men, 5.37%; women, 7.15%). Further, 22.25% study population had MS (abdominal obesity, 27.98%; hypertriglyceridemia, 30.09%; low high-density cholesterol levels, 19.74%; high blood pressure, 43.45%; and high fasting glucose levels, 30.44%). Multivariate-adjusted analysis indicated that proteinuria risk increased in participants with MS (odds ratio [OR] 1.884, 95% confidence interval [CI] 1.867–1.902, P<0.001). The presence of MS was associated with eGFR<60 mL/min/1.73 m2 (OR 1.364, 95% CI 1.355–1.373, P<0.001). MS individual components were also associated with an increased CKD risk. The strength of association between MS and the development of CKD increase as the number of components increased from 1 to 5. In sub-analysis by men and women, MS and its each components were a significant determinant for CKD. Conclusions MS and its individual components can predict the risk of prevalent CKD for men and women.

Activation of the Renal PI3K/Akt/mTOR Signaling Pathway in a DOCA-Salt Model of Hypertension

The present study investigated the changes that occurred in the mammalian target of rapamycin (mTOR) signaling pathway in the kidney as a result of deoxycorticosterone acetate (DOCA)-salt hypertension. Rats were implanted with DOCA strips (200 mg/kg) 1 week after unilateral nephrectomy and were then supplied with 0.9% saline to drink. Four weeks after DOCA implantation, systolic blood pressure (SBP) was measured by use of the tail-cuff method. The expression levels of phosphorylated phosphatidylinositol-3-kinase (PI3K), Akt, and mTOR, as well as the protein expression levels of ED-1 and cyclooxygenase-2 (COX-2), transforming growth factor-β1 (TGF-β1), α-smooth muscle actin (SMA), caspase-3, Bax, and Bcl-2, were then examined in the kidney by semiquantitative immunoblotting. DOCA-salt hypertensive rats were found to have significantly increased SBP as well as an increased kidney weight-to-body weight ratio. Moreover, the phosphorylation of PI3K, Akt, and mTOR was increased in the kidney of DOCA-salt hypertensive rats compared with the control, as was the protein expression of ED-1, COX-2, TGF-β1, and α-SMA. The expression levels of caspase-3 and Bax were increased significantly, whereas Bcl-2 expression was decreased. In conclusion, the phosphorylation of PI3K/Akt/mTOR was increased in the kidney of DOCA-salt hypertensive rats.

Prevalence and associations for abnormal bleeding times in patients with renal insufficiency.

Platelet dysfunction and associated hemorrhagic complications are often encountered in patients with chronic kidney disease. This study aimed to evaluate the prevalence and associations for abnormal bleeding time (BT) in patients with renal dysfunction. Hemoglobin, hematocrit, platelet, blood urea nitrogen, creatinine, and parathyroid hormone levels were determined in 1716 patients (55.18 ± 17.19 years, men 50.8%). For these patients, BTs were estimated using a platelet function analyzer-100. Glomerular filtration rates (GFRs) were estimated using the Chronic Kidney Disease Epidemiology Collaboration equation. The study population was divided into six groups according to the estimated GFR (eGRF): group I, eGFR ≥ 90 ml/min/1.73 m2; group II, 60 ≤ eGFR < 90 ml/min/1.73 m2; group III, 30 ≤ eGFR < 60 ml/min/1.73 m2; group IV, 15 ≤ eGFR < 30 ml/min/1.73 m2; group V, eGFR < 15 ml/min/1.73 m2; and group VI, undergoing regular hemodialysis. Renal insufficiency was defined as eGFR < 60 ml/min/1.73 m2. To further investigate the role of inflammatory cytokines, nitric oxide (NO) and tumor necrosis factor alpha (TNF-α) were measured in a 327-patient subset of the total patient population (52.82 ± 18.3 years, men 60.9%). Abnormal BT occurred in 11.8% of group I, 15.3% of group II, 29.1% of group III, 37.5% of group IV, 35.0% of group V, and 32.1% of group VI. By Pearson correlation coefficient, eGFR (r = −0.089), hemoglobin (r = −0.127), platelet (r = −0.054) were correlated with BT. Multivariate analysis revealed that age [odds ratio (OR), 1.013; 95% CI, 1.004–1.022], renal insufficiency (eGFR < 60 ml/min/1.73 m2; OR, 2.271; 95% CI, 1.672–3.083), anemia (hemoglobin < 120 g/l; OR, 1.486; 95% CI, 1.089–2.027), and thrombocytopenia (platelet < 150 × 109/l; OR, 1.445; 95% CI, 1.089–1.918) were independently associated with prolonged BT. Plasma levels of NO and TNF-α were increased in patients with renal insufficiency (eGFR < 60 ml/min/1.73 m2). Plasma levels of NO in renal insufficiency group were higher in prolonged BT than those in normal BT. A significant positive correlation was noted between BTs and NO levels (r = 0.152, p = 0.009) but not with TNF-α levels. The prevalence of abnormal BTs was higher as eGFR declined. Old age, renal insufficiency, anemia, and thrombocytopenia were independent associations for abnormal BT.

Association of Age and BP Variability with Long-term Mortality in Hemodialysis Patients

Background/Aims: Blood pressure (BP) variability is known as a poor prognostic factor for cardiovascular outcomes. This study assessed the prognostic significance of BP variability in association with increasing age in hemodialysis patients. Methods: We retrospectively analyzed 2,174 patients on hemodialysis from March 2005 to December 2012. The impact of intradialytic and interdialytic BP variability on all-cause mortality according to age groups was analyzed. Results: Kaplan-Meier survival curves for 5-year cumulative mortality showed higher mortality in patients with higher intradialytic systolic and diastolic BP variability as well as interdialytic systolic and diastolic BP variability (log-rank p=0.006, <0.001, 0.018 and < 0.001) in patients aged <55 years, but not in older age groups. Cox proportional analysis revealed that 5-year mortality was associated with intradialytic diastolic BP variability in patients aged <55 years (HR, 2.03 CI, 1.24-3.32). Conclusion: The overall mortality was associated with BP variability in patients aged <55 years, but not in older ages. This result suggests that younger hemodialysis patients with BP variability require further medical attention and intervention to reduce BP variability.

Decreased Renal Expression of H(+)-ATPase and Pendrin in a Patient with Distal Renal Tubular Acidosis Associated with Sjögren's Syndrome.

A 31-year-old woman with no significant past medical or family history was admitted with complaints of general weakness. Laboratory tests revealed: serum potassium 3.0 mEq/L, arterial blood pH 7.28, serum bicarbonate 17.8 mEq/L and urinary pH 7.0. Double-labeling confocal fluorescence microscopy using H(+)-ATPase and pendrin antibodies demonstrated a decreased expression of these proteins in the patients renal collecting duct compared to normal controls. Anti-Sjögrens-syndrome-related antigen A (Anti-Ro/SS-A) and anti-Sjögrens syndrome type B (anti-La/SS-B) antibodies were strongly positive with very high titers, consistent with Sjögrens syndrome. We present a case of distal renal tubular acidosis-associated Sjögrens syndrome with a defect in H(+)-ATPase and pendrin in the renal collecting duct.

Effects of Spironolactone in Combination with Angiotensin-Converting Enzyme Inhibitors or Angiotensin Receptor Blockers in Patients with Proteinuria

Background/Aims: This study aimed to investigate the potential beneficial anti-proteinuric effect of an add-on aldosterone blockade and the impact of the aldosterone escape phenomenon. Methods: We retrospectively analyzed data of 304 patients with persistent proteinuria, who were administered spironolactone (25 mg/day) after treatment with angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) for >3 months. Patients were divided according to their aldosterone levels during ACEI/ARB treatment into an escape group (plasma aldosterone >80 pg/mL, N=95, 31.5%) and a non-escape group (plasma aldosterone ≤80 pg/mL, N=209, 68.5%) and according to their urine albumin-to-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR). Results: After 12 months, the UACR decreased significantly in patients with 1≤UACR<3.5 g/g Cr, UACR ≥3.5 g/g Cr, and eGFR ≥60 mL/min/1.73 m2, and in the non-escape group. Severe hyperkalemia (K≥7.0 mEq/L) developed in 9 of 137 patients with eGFR<60 mL/min/1.73 m2 (6.5%) and in none of the 167 patients with eGFR≥60 mL/min/1.73 m2. Conclusions: Proteinuria decreased significantly after add-on spironolactone treatment in patients with 1≤UACR<3.5 g/g Cr, UACR ≥3.5 g/g Cr, and eGFR ≥60 mL/min/1.73 m2, and in the non-escape group. The anti-proteinuric effect of spironolactone may vary according to the degree of albuminuria, impaired eGFR, and aldosterone escape.

Biomarkers Predicting Survival of Sepsis Patients Treated with Continuous Renal Replacement Therapy

The present study investigated the prognostic factors predicting survival of patients with sepsis and acute kidney injury (AKI) undergoing continuous renal replacement therapy (CRRT). This retrospective observational study included 165 sepsis patients treated with CRRT. The patients were divided into two groups; the survivor group (n=73, 44.2%) vs. the nonsurvivor group (n=92, 55.8%). AKI was defined by the 2012 Kidney Disease: Improving Global Outcomes Clinical Practice Guidelines. We analyzed medical histories, clinical characteristics and laboratory findings of the enrolled patients when they started CRRT. In addition, we performed binary logistic regression and cox regression analysis. In the survivor group, urine output during the first day was significantly higher compared with the nonsurvivor group (55.7±66.3 vs. 26.6±46.4, p=0.001). Patients with urine output <30 mL/hour during the 1st day showed worse outcomes than ≥30 mL/hour in the logistic regression (hazard ratio 2.464, 95% confidence interval 1.152-5.271, p=0.020) and the cox regression analysis (hazard ratio 1.935, 95% confidence interval 1.147-3.263, p=0.013). In conclusion, urine output may predict survival of septic AKI patients undergoing CRRT. In these patients, urine output <30 mL/hour during the first day was the strongest risk factor for in-hospital mortality.