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: 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.

 

Objectives: To evaluate the predictive value of V/Q scanning in patients with impaired renal function.

Methods: We assessed all patients with impaired renal function who underwent V/Q scanning. The patients studied included those who also had CTPA (group 1) and those who did not (group 2). We recorded the results of V/Q scanning, chest X-rays, CTPA, D-dimer levels, ultrasound of deep veins, and clinical probability for PE (Wells' score) in group 1. CTPA results were considered true results. Anticoagulant treatment was documented in all the patients.

Results: Of the 45 patients in group 1, 12 (22%) had positive CTPA for PE. The positive predictive value (PPV) for patients with high probability results on V/Q scanning for PE was 30%. Restricting results to D-dimer levels ≥ 1000 ng/ml added little to this value. Restricting results to Wells’ score ≥ 7 resulted in 72% PPV. The negative predictive values for low or moderate probability were ~79 % and ~67% respectively. Of the 95 patients in group 2, all those with high probability for PE were treated with anticoagulants.

Conclusions: Patients with impaired renal function and high probability for PE on V/Q scanning had very low PPV for PE. Due to the lack of CTPA studies, patients with high probability for PE on V/Q scanning were treated with anticoagulants.

Background: Percutaneous angioplasty (PTA) and stenting is an established procedure for the treatment of hypertension caused by atherosclerotic renal artery stenosis. However recently, the decision whether or not to perform this procedure has raised considerable debate.

Objectives: To examine the association between the basic clinical and radiological characteristics of candidates for renal artery PTA and the clinical outcome of the procedure in terms of improvement of blood pressure control and renal function.

Methods: We conducted a retrospective cohort study of all patients who underwent percutaneous transluminal renal artery angioplasty (PTRA) and stent implantation in a tertiary medical center during the period 2000–2007. The clinical and radiological data were extracted from the medical file of each patient. Blood pressure measurements and creatinine level were recorded before the procedure and 1 month, 6 months, 12 months and 18 months after PTRA.

Results: Thirty-two patients were included in the final statistical analysis. The mean age of the study population was 66.6 ± 8.8 years old and 75% were men. There was a significant reduction in both systolic and diastolic blood pressure 1 month after the procedure: 160.5 ± 24.7 vs. 141.8 ± 23.6 mmHg and 83.8 ± 12.9 vs. 68.8 ± 11.8 mmHg respectively (P < 0.001). The reduction in blood pressure was constant throughout the follow-up period and was evident 18 months after the procedure: 160.5 ± 24.7 vs. 135.0 ± 35.1 mmHg and 83.8 ± 12.9 vs. 71.3 ± 16.5 mmHg respectively (P < 0.001). However, no improvement in renal function was observed at any time during the follow-up period. We could not demonstrate an association between clinical or radiological features and the clinical outcome after PTRA.

Conclusions: Our findings show that PTRA[1] can be considered an effective procedure for improving blood pressure control in patients with atherosclerotic renal artery stenosis (ARAS) and resistant hypertension. This research, together with previous studies, strengthens the knowledge that the decline in glomerular filtration rate seen in many patients with ARAS is non-reversible and is not improved by PTRA.

Objectives: To investigate the mechanisms of these effects.

Methods: The study group included 106 long-term care stable geriatric inpatients. Diet and drugs were kept stable. The study lasted 5 weeks; during the first 2 weeks 100 mg aspirin was administered once a day. Clinical and laboratory follow-up were performed at baseline and weekly for the next 3 weeks. The glomerular filtration rate was estimated by creatinine clearance measured in 24 hour urine and serum creatinine, and by the Cockcroft-Gault formula (C-G) equation. Uric acid clearance (Cu acid) was determined from serum concentrations and 24 hour excretion of uric acid. Patients with serum creatinine > 1.5 mg/dl were not included.

Results: After 2 weeks on low dose aspirin, measured creatinine and uric acid clearances decreased significantly compared with the initial values in 70% and 62% of the patients, respectively, with mean decreases of 19% and 17%, respectively (P < 0.001). Blood urea nitrogen increased by 17% while serum creatinine and uric acid concentrations increased by 4% (P < 0.05 for all). The C-G[1] values decreased by 3% (P < 0.05). After withdrawal of aspirin all parameters improved. However, 67% of the patients remained with some impairment in their measured Ccr[2], compared to baseline. Patients who reacted adversely to low dose aspirin had significantly better pre-study renal function (Ccr), lower hemoglobin and lower levels of serum albumin.

Conclusions: Short-term low dose aspirin affected renal tubular creatinine and uric acid transport in the elderly, which may result in a prolonged or permanent deterioration of the renal function. It is suggested that renal functions be monitored even with the use of low dose aspirin in elderly patients.