Israel Medical Association Journal

Recent studies using propensity score matching have clearly indicated that contrast nephropathy following computed tomography occurs in hospitalized patients with advanced chronic kidney disease (eGFR < 30 ml/min/1.73 m²) and that this iatrogenic complication is likely underestimated because of concomitant renal functional recovery, unrelated to the imaging procedure. These findings should be considered regarding contrast-enhanced studies in such patients.

Background: Among chronic kidney disease (CKD) patients, baseline neutrophil gelatinase-associated lipocalin (NGAL) may reflect the severity of renal impairment. No data exists on serial changes in serum NGAL levels in CKD patients before and after percutaneous coronary intervention (PCI).

Objectives: To evaluate serial serum NGAL levels relation to contrast induced acute kidney injury (CI-AKI) following PCI.

Methods: The study included 58 patients with CKD who underwent elective PCI. Plasma NGAL measurements were performed before (pre-NGAL) and 24 hours following (post-NGAL) PCI. Patients were followed for CI-AKI and changes in NGAL levels. Receiver operator characteristic identified the optimal sensitivity and specificity for pre-NGAL levels compared with post-NGAL for patients with CI-AKI.

Results: Overall CI-AKI incidence was 33%. Both pre-NGAL (172 vs. 119 ng/ml, P < 0.001) and post-NGAL (181 vs. 121 ng/ml, P < 0.001) levels were significantly higher in patients with CI-AKI, but no significant changes were detected. Pre-NGAL levels were similar to post-NGAL levels in predicting CI-AKI (area under the curve 0.753 vs. 0.745). Optimal cutoff value for pre-NGAL was 129 ng/ml (sensitivity of 73% and specificity of 72%, P < 0.001). Post-NGAL levels > 141 ng/ml were independently associated with CI-AKI (hazard ratio [HR] 4.86, 95% confidence interval [95%CI] 1.34–17.64, P = 0.02) with a strong trend for post-NGAL levels > 129 ng/ml (HR 3.46, 95%CI 1.23–12.81, P = 0.06).

Conclusions: In high-risk patients, pre-NGAL levels may predict CI-AKI. Further studies on larger populations are needed to validate the use of NGAL measurements in CKD patients.

Background: Among dialysis patients, occlusive mesenteric vascular disease has rarely been reported.

Objectives: To report on the experience of one center with regard to diagnosing and treating this complication.

Methods: The retrospective case-series involved six patients (3 females, 3 males; age 52–88 years; 5/6 were smokers) on chronic hemodialysis at a single center. All patients with symptoms suggestive of occlusive mesenteric disease and a subsequent angiographic intervention were included. Demographic, clinical, and laboratory data were collected from patient charts for the period before and after angioplasty and stenting of the mesenteric vessels. A Wilcoxon signed-rank test was used to compare the relevant data before and after the intervention.

Results: All participants had variable co-morbidities and postprandial abdominal pain, food aversion, and weight loss. CT angiography was limited due to heavy vascular calcifications. All underwent angioplasty with stenting of the superior mesenteric artery (4 patients) or the celiac artery (2 patients). All procedures were successful in resolving abdominal pain, malnutrition, and inflammation. Weight loss before was 15 ± 2 kg and weight gain after was 6 ± 2 kg. C-reactive protein decreased from 13.4 ± 5.2 mg/dl to 2.2 ± 0.4 mg/dl (P < 0.05). Serum albumin increased from 3.0 ± 0.2 g/dl to 3.9 ± 0.1 g/dl (P < 0.05). Two patients underwent a repeat procedure (4 years, 5 months, respectively). Follow-up ranged from 0.5–7 years.

Conclusions: Occlusive mesenteric ischemia occurs among dialysis patients. The diagnosis requires a high degree of suspicion, and it is manageable by angiography and stenting of the most involved mesenteric artery.

Background: Both cigarette smoking and chronic kidney disease (CKD) are linked to cardiovascular morbidity and development of atherosclerosis. However, the relationship between cigarette smoking and renal function is not clearly understood. 

Objectives: To investigate the relationship between cigarette smoking and renal function, and determine whether the intensity of cigarette smoking influences renal function.

Methods: We conducted a retrospective analysis of subjects attending the screening center at the Rabin Medical Center. Subjects were classified as smokers, non-smokers and past smokers. Renal function was evaluated by means of the CKD-EPI equation for estimating glomerular filtration rate (eGFR). Multivariate and gender-based analyses were performed.

Results: The study population comprised 24,081 participants, of whom 3958 (17%) were classified current smokers, and 20,123 non-smokers of whom 4523 were classified as past smokers. Current smokers presented a higher eGFR compared to the non-smoking group (100.8 vs. 98.7, P < 0.001) as well as higher rates of proteinuria (15.3% vs. 9.3%, P < 0.001). The difference in eGFR between smokers and non-smokers was more significant in males than in females. Past smokers had the lowest eGFR of all groups, this difference remained significant after age adjustments (P = 0.005). 

Conclusions: Cigarette smoking is associated with higher eGFR compared to non-smoking. This difference was more pronounced in males than females, implying a gender-based difference. The higher prevalence of proteinuria in smokers suggests a mechanism of hyperfiltration, which might result in future progressive renal damage.

 

Background: Chronic kidney disease (CKD) is often accompanied by impairment of cardiac function that may lead to major cardiac events. Erythropoietin (EPO), a kidney-produced protein, was shown to be beneficial to heart function. It was suggested that reduced EPO secretion in CKD may play a role in the initiation of heart damage. 

Objectives: To investigate molecular changes in the EPO/erythropoietin receptor (EPO-R) axis in rat cardiomyocytes using a rat model for CKD.

Methods: We established a rat model for CKD by kidney resection. Cardiac tissue sections were stained with Masson’s trichrome to assess interstitial fibrosis indicating cardiac damage. To evaluate changes in the EPO/EPO-R signaling cascade in the myocardium we measured cardiac EPO and EPO-R as well as the phosphorylation levels of STAT-5, a downstream element in this cascade.

Results: At 11 weeks after resection, animals presented severe renal failure reflected by reduced creatinine clearance, elevated blood urea nitrogen and presence of anemia. Histological analysis revealed enhanced fibrosis in cardiac sections of CKD animals compared to the sham controls. Parallel to these changes, we found that although cardiac EPO levels were similar in both groups, the expression of EPO-R and the activated form of its downstream protein STAT-5 were significantly lower in CKD animals.

Conclusions: CKD results in molecular changes in the EPO/EPO-R axis. These changes may play a role in early cardiac damage observed in the cardiorenal syndrome.

 

Abstract

Background: Renal hemangiomas are rare benign tumors seldom distinguished from malignant tumors preoperatively.

Objectives: To describe the Memorial Sloan-Kettering Cancer Center (MSKCC) experience with diagnosing and treating renal hemangiomas, and to explore possible clinical and radiologic features that can aid in diagnosing renal hemangiomas preoperatively.

Methods: Patients with renal hemangiomas treated at MSKCC were identified in our prospectively collected renal tumor database. Descriptive statistics were used to describe the patient characteristics and the tumor characteristics. All available preoperative imaging studies were reviewed to assess common findings and explore possible characteristics distinguishing benign hemangiomas from malignant renal tumors preoperatively.

Results: Of 6341 patients in our database 15 were identified. Eleven (73%) were males, median age at diagnosis was 53.3 years, and the affected side was evenly distributed. All but two patients were treated surgically. The mean decrease in estimated glomerular filtration rate (eGFR) after surgery was 36.3%; one patient had an abnormal presurgical eGFR and only two patients had a normal eGFR after surgery. We could not identify radiographic features that would make preoperative diagnosis certain, but we did identify features characteristic of hepatic hemangiomas that were also present in some of the renal hemangiomas.

Conclusions: Most renal hemangiomas cannot be distinguished from other common renal cortical tumors preoperatively. In select cases a renal biopsy can identify this benign lesion and the deleterious effects of extirpative surgery can be avoided.

Background: Late nephrology referral, before initiation of dialysis treatment, is associated with adverse outcome.

Objectives: To investigate the implications of late nephrology referral on mortality among dialysis patients in Israel.

Methods: We retrospectively analyzed 200 incident dialysis patients. Patients were defined as late referrals if they started dialysis less than 3 months after their first nephrology consultation. Survival rates and risk factors for mortality were analyzed

Results: The early referral (ER) group comprised 118 patients (59%) and the late referral (LR) group 82 patients (41%). The mortality rate was 44.5% (53 patients) in the ER and 68% (n=56) in the LR group. The 4 year survival rate was 41.1% in the ER and 18.7% in the LR group (P < 0.0001). The mortality rate increased with late nephrology referral (HR 1.873, 95%CI 1.133–3.094), with age (HR 1.043 for each year, 95%CI 1.018–1.068), with diabetes (HR 2.399, CI 1.369-4.202), and with serum albumin level (HR 0.359 for an increase of each 1 g/dl, 95%CI 0.242–0.533). The median survival time was higher for the ER group in women, in patients younger than 70, and in diabetic patients. A trend for longer survival time was found in non-diabetic patients. Survival time was not increased in early referred patients older than 70 and in male patients.

Conclusions: Late nephrology referral is associated with an overall higher mortality rate in dialysis patients. The survival advantage of early referral may have a different significance in specific subgroups. The timing of nephrology referral should be considered as a modifiable risk factor for mortality in patients with end-stage renal disease. 

Background: Kidney disease and cardiovascular disease seem to be lethally synergistic and both are approaching the epidemic level. A reduced glomerular filtration rate is associated with increased mortality risk in patients with heart failure. Many patients with congestive heart failure are anemic. Anemia is very often associated with chronic kidney disease.

Objectives: To assess – in relation to New York Heart Association class – the prevalence of anemia and chronic kidney disease in patients with normal serum creatinine in a cohort of 526 consecutive patients with coronary artery disease undergoing percutaneous coronary interventions.

Methods: GFR[1] was estimated using the simplified MDRD formula, the Cockcroft-Gault formula, the Jeliffe and the novel CKD-EPI formula.

Results: According to the WHO definition the prevalence of anemia in our study was 21%. We observed a progressive decline in GFR and hemoglobin concentration together with a rise in NYHA[2] class. Significant correlations were observed between eGFR[3] and systolic blood pressure, diastolic blood pressure, age, NYHA class, complications of PCI[4], including bleeding, and major adverse cardiac events.

Conclusions: The prevalence of anemia and chronic kidney disease is high in patients undergoing PCI despite normal serum creatinine, particularly in higher NYHA class. Lower eGFR and hemoglobin are associated with more complications, including bleeding after PCI and higher prevalence of major adverse cardiac events. In patients with risk factors for cardiovascular disease, GFR should be estimated since renal dysfunction and subsequent anemia are important risk factors for cardiovascular morbidity and mortality.