Israel Medical Association Journal

Background: Data suggest that subclinical hypothyroidism (SCH) is associated with progression of chronic renal disease; however, no study to date has assessed the possible relation between SCH and acute deterioration of renal function.

Objectives: To investigate the possible relation between SCH and acute kidney injury (AKI) in a large cohort of patients with ST-elevation myocardial infarction (STEMI) treated with primary coronary intervention (PCI).

Methods: We evaluated thyroid stimulating hormone (TSH) and free T4 levels of 1591 STEMI patients with no known history of hypothyroidism or thyroid replacement treatment who were admitted to the coronary care unit (October 2007–August 2017). The presence of SCH was defined as TSH levels ≥ 5 mU/ml in the presence of normal free T4 levels. Patients were assessed for development of AKI ( 0.3 mg/dl increase in serum creatinine, according to the KDIGO criteria).

Results: The presence of SCH was demonstrated in 68/1593 (4.2%) STEMI patients. Patients presenting with SCH had more AKI complications during the course of STEMI (20.6% vs. 9.6 %; P = 0.003) and had significantly higher serum creatinine change throughout hospitalization (0.19 mg/dl vs. 0.08 mg/dl, P = 0.04). No significant difference was present in groups regarding baseline renal function and the amount of contrast volume delivered during coronary angiography. In multivariate logistic regression model, SCH was independently associated with AKI (odds ratio = 2.19, 95% confidence interval 1.05–4.54, P =0.04).

Conclusions: Among STEMI patients treated with PCI, the presence of SCH is common and may serve as a significant marker for AKI.

Background: Kidney transplantation is associated with early improvement in cardiac function and structure; however, data on cardiac adaptation and its relation to kidney allograft function remain sparse.

Objectives: To investigate the relationship between post-transplant kidney function and echocardiographic measures in patients with normal/preserved pre-transplant cardiac structure and function.

Methods: The study included 113 patients who underwent kidney transplantation at a single tertiary medical center from 2000 to 2012. The patients were evaluated by echocardiography before and after transplantation, and the relation between allograft function and echocardiographic changes was evaluated. Echocardiography was performed at a median of 510 days after transplantation.

Results: The post-transplantation estimated glomerular filtration rate (eGFR) was directly correlated with left ventricular (LV) systolic function and inversely correlated with LV dimensions, LV wall thickness, left atrial diameter, and estimated systolic pulmonary arterial pressure. In patients with significant allograft dysfunction (eGFR ≤ 45 ml/min), LV hypertrophy worsened, with no improvement in LV dimensions. In contrast, in patients with preserved kidney function, there was a significant reduction in both LV diameter and arterial pulmonary systolic pressure.

Conclusions: Our results show that in kidney transplant recipients, allograft function significantly affects cardiac structure and function. Periodic echocardiographic follow-up is advisable, especially in patients with kidney graft dysfunction.

Background: Risk factors for bleeding complications after percutaneous kidney biopsy (PKB) and the role of primary hemostasis screening are not well established.

Objectives: To determine the role of primary hemostasis screening and complication outcomes among individuals who underwent PKB.

Methods: We reviewed data of 456 patients who underwent PKB from 2010 to 2016 in a large university hospital. In 2015, bleeding time (BT) testing was replaced by light transmission aggregometry (LTA) as a pre-PKB screening test.

Results: Of the 370 patients who underwent pre-PKB hemostasis screening by BT testing, prolonged BT was observed in 42 (11.3%). Of the 86 who underwent LTA, an abnormal response was observed in 14 (16.3%). Overall, 155 (34.0%) patients experienced bleeding: 145 (31.8%) had minor events (hemoglobin fall of 1–2 g/dl, macroscopic hematuria, perinephric hematoma without the need for transfusion or intervention) and 17 (3.7%) had major events (hemoglobin fall > 2 g/dl, blood transfusion or further intervention). Abnormal LTA response did not correlate with bleeding (P = 0.80). In multivariate analysis, only prolonged BT (P = 0.0001) and larger needle size (P = 0.005) were identified as independent predictors of bleeding.

Conclusions: Bleeding complications following PKB were common and mostly minor, and the risk of major bleeding was low. Larger needle size and prolonged BT were associated with a higher bleeding risk. Due to the relatively low risk of major bleeding and lack of benefit of prophylactic intervention, the use of pre-PKB hemostasis screening remains unestablished.

Background: Sodium-glucose cotransporter 2 inhibitors (SGLT2i) (such as canagliflozin, empagliflozin, and dapagliflozin) are widely used to treat patients with type 2 diabetes mellitus (T2DM) to improve glycemic, cardiovascular and renal outcomes. However, based on post-marketing data, a warning label was added regarding possible occurrence of acute kidney injury (AKI).

Objectives: To describe the clinical presentation of T2DM patients treated with SGLT2i who were evaluated for AKI at our institution and to discuss the potential pathophysiologic mechanisms.

Methods: A retrospective study of a computerized database was conducted of patients with T2DM who were hospitalized or evaluated for AKI while receiving SGLT2i, including descriptions of clinical and laboratory characteristics, at our institution.

Results: We identified seven patients in whom AKI occurred 7–365 days after initiation of SGLT2i. In all cases, renin-angiotensin-aldosterone system blockers had also been prescribed. In five patients, another concomitant nephrotoxic agent (injection of contrast-product, use of nonsteroidal anti-inflammatory drugs or cox-2 inhibitors) or occurrence of an acute medical event potentially associated with AKI (diarrhea, sepsis) was identified. In two patients, only the initiation of SGLT2i was evident. The mechanisms by which AKI occurs under SGLT2i are discussed with regard to the associated potential triggers: altered trans-glomerular filtration or, alternatively, kidney medullary hypoxia.

Conclusions: SGLT2i are usually safe and provide multiple benefits for patients with T2DM. However, during particular medical circumstances, and in association with usual co-medications, particularly if baseline glomerular filtration rate is decreased, patients treated with SGLT2i may be at risk of AKI, thus warranting caution when prescribed.

Background: Sonographic assessment of the fetal kidneys is an integral part of the prenatal anatomical survey.

Objectives: To evaluate the fetal renal to abdominal (RTA) ratio throughout pregnancy and to investigate whether this ratio can be a potential diagnostic landmark for congenital anomalies of the kidney and urinary tract (CAKUT).

Methods: Measurements of the anterior-posterior diameters of the fetal kidney and fetal abdomen (APAD) were obtained prospectively. The RTA was calculated as the ratio between them in in two groups: normal population vs. CAKUT cases. RTA in CAKUT cases was compared to RTA in a normal population.

Results: The study group was comprised of 210 women. The mean gestational age for the fetuses was 31 ± 5.6 weeks (range 14–40 weeks). Fetal RTA ratio was found to be 0.28 ± 0.03 throughout pregnancy from early second trimester to term, with high reproducibility of measurements. During the study period the RTA was evaluated in nine cases referred for suspected CAKUT. All cases demonstrated a different ratio according to the renal anomaly. High ratio was observed in one case of overgrowth syndrome (Beckwith Wiedenmann syndrome; 0.47), three cases of infantile polycystic kidney (0.45–0.47), and three cases of a solitary kidney (0.31–0.35), while cases of dysplastic kidneys revealed a low ratio (0.14–0.18).

Conclusions: Prenatal RTA ratio is constant throughout gestation. An abnormal ratio should lead to meticulous renal investigation to rule out kidney disease.

Background: Idiopathic membranous nephropathy (IMN) is one of the most common causes of nephrotic syndrome (NS) in Caucasian adults. Most patients have good renal prognosis, but 30–40% may progress to end stage renal disease (ESRD). 

Objectives: To evaluate the efficacy and safety of immunosuppressive treatment (IST) in high-risk patients.

Methods: All IMN patients diagnosed by kidney biopsy from 2004–2010 were included. Clinical and laboratory data were collected at each follow-up visit. Risk assessment for renal progression classified patients as high risk if: 24 hour protein excretion > 6 g/day, estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m2, and severe disabling or life-threatening clinical symptoms of NS were present.

Results: Among 290 biopsies, 37 patients (12.7%) were IMN. They were allocated to the high-risk IST group (n=16) or low-risk supportive treatment (ST) group (n=21) according to the likelihood of developing renal failure. Mean follow-up was 47 ± 17.3 months. Complete and partial remission rate was 68.7% for high-risk IST vs. 90.4% for low-risk ST. In the high-risk IST group, eGFR was significantly lower at 30 months (65.5 ± 28.6 vs. 85.3 ± 21.6 at baseline, P < 0.05). Four high-risk patients reached ESRD. In the low-risk ST group, eGFR remained stable at 30 and 60 months. 

Conclusions: This study showed a high remission rate for IMN. IST with prednisolone and cyclophosphamide provided favorable renal outcomes in most high-risk patients. The very high remission rate obtained in the low-risk patients confirms the adequacy of supportive treatment in this group.

Background: Early surgical correction of congenital heart malformations in neonates and small infants may be complicated by acute kidney injury (AKI), which is associated with higher morbidity and mortality rates, especially in patients who require dialysis. Glomerular filtration rate (GFR) is considered the best measurement of renal function which, in neonates and infants, is highly dependent on heart function. 

Objective: To determine whether measurements of creatinine clearance after open heart surgery in neonates and young infants can serve as an early indicator of surgical success or AKI.

Method: We conducted a prospective observational study in 19 neonates and small infants (body weight < 5 kg) scheduled for open heart surgery with cardiopulmonary bypass. Urine collection measurement of creatinine clearance and albumin excretion was performed before and during surgery and four times during 48 hours after surgery.

Results: Mean creatinine clearance was lowest during surgery (25.2 ± 4. ml/min/1.73 m2) and increased significantly in the first 16 hours post-surgery (45.7 ± 6.3 ml/min/1.73 m2). A similar pattern was noted for urine albumin which was highest during surgery (203 ± 31 µg/min) and lowest (93 ± 20 µg/min) 48 hours post-surgery. AKI occurred in four patients, and two patients even required dialysis. All six showed a decline in creatinine clearance and an increase in urine albumin between 8 and 16 hours post-surgery. 

Conclusions: In neonates and small infants undergoing open heart surgery, a significant improvement in creatinine clearance in the first 16 hours postoperatively is indicative of a good surgical outcome. This finding has important implications for the early evaluation and treatment of patients in the intensive care unit on the first day post-surgery.

 

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.