Israel Medical Association Journal

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: Proteinuria and albuminuria are markers of kidney injury and function, serving as a screening test as well as a means of assessing the degree of kidney injury and risk for cardiovascular disease and death in both the diabetic and the non-diabetic general population.

Objectives: To evaluate the association between proteinuria below 300 mg/24 hours and albuminuria, as well as a possible association with kidney function in patients with diabetes mellitus (DM).

Methods: The medical files of patients with type 1 and type 2 DM with proteinuria below 300 mg/24 hours at three different visits to the Diabetic Nephropathy Clinic were screened. This involved 245 patient files and 723 visits. The data collected included demographics; protein, albumin and creatinine levels in urine collections; blood biochemistry; and clinical and treatment data. 

Results: The association between proteinuria and albuminuria is non-linear. However, proteinuria in the range of 162–300 mg/24 hours was found to be linearly and significantly correlated to albuminuria (P < 0.001, r = 0.58). Proteinuria cutoff, based on albuminuria cutoff of 30 mg/24 hours, was found to be 160.5 mg/24 hr. Body mass index (BMI) was the sole independent predictor of proteinuria above 160.5 mg/24 hr. Changes in albuminuria, but not proteinuria, were associated with changes in creatinine clearance. 

Conclusions: A new cutoff value of 160.5 mg/hr was set empirically, for the first time, for abnormal proteinuria in diabetic patients. It appears that proteinuria below 300 mg/24 hr is not sufficient as a sole prognostic factor for kidney failure.