Timing of Pregnancy After Kidney Transplantation and Risk of Allograft Failure.

The optimal timing of pregnancy after kidney transplantation remains uncertain. We determined the risk of allograft failure among women who became pregnant within the first 3 posttransplant years. Among 21 814 women aged 15-45 years who received a first kidney-only transplant between 1990 and 2010 captured in the United States Renal Data System, n = 729 pregnancies were identified using Medicare claims. The probability of allograft failure from any cause including death (ACGL) at 1, 3, and 5 years after pregnancy was 9.6%, 25.9%, and 36.6%. In multivariate analyses, pregnancy in the first posttransplant year was associated with an increased risk of ACGL (hazard ratio [HR]: 1.18; 95% confidence interval [CI] 1.00, 1.40) and death censored graft loss (DCGL) (HR:1.25; 95% CI 1.04, 1.50), while pregnancy in the second posttransplant year was associated with an increased risk of DCGL (HR: 1.26; 95% CI 1.06, 1.50). Pregnancy in the third posttransplant year was not associated with an increased risk of ACGL or DCGL. These findings demonstrate a higher incidence of allograft failure after pregnancy than previously reported and that the increased risk of allograft failure extends to pregnancies in the second posttransplant year.

Parenteral vitamin B12 in macrocytic hemodialysis patients reduced MMA levels but did not change mean red cell volume or hemoglobin.

AIMS: Unexplained macrocytic anemia was common in our hemodialysis (HD) unit. Vitamin B12 requirements may be higher in HD patients; therefore, patients may be deficient despite "normal" serum levels. We studied vitamin B12 status and the effect of parenteral vitamin B12 administration in macrocytic HD patients. A normocytic group was included for comparison. MATERIALS AND METHODS: Prospective cohort study of 62 HD patients (34 macrocytic, 28 normocytic) from November 2008 to March 2009. Patients were on stable doses of darbepoetin and iron replete. Vitamin B12 1,000 µg IV was given once weekly for 4 weeks and follow-up was 12 weeks. Methylmalonic acid (MMA) level was used as an indicator of vitamin B12 status. MCV and hemoglobin were also examined for an effect of B12 administration. RESULTS: At baseline: all patients had serum B12 levels > 200 pmol/l; 97% had serum folate levels > 55 nmol/l; there was no difference in serum B12 levels between groups (504 vs. 571 pmol/l, p = 0.18); MMA was higher in the macrocytic group (0.56 vs. 0.48 µmol/l, p = 0.048) and hemoglobin (Hg) was lower (119 vs. 125 g/l, p = 0.03); median darbepoetin dose was equivalent (20 µg/week). Following IV vitamin B12, the macrocytic group had a greater and more sustained reduction in MMA (-0.064 vs. -0.0066 µmol/l/wk, p = 0.004). There was no improvement in hemoglobin (Hg), reticulocyte count or MCV in either group. Median darbepoetin dose was unchanged. CONCLUSIONS: IV vitamin B12 led to a sustained decline in MMA levels in macrocytic patients, suggesting functional vitamin B12 deficiency at baseline. However, there were no significant changes in Hg or darbepoetin dose.

The pregnancy rate and live birth rate in kidney transplant recipients.

Fertility is one of the potential benefits for women undergoing kidney transplantation; however, population-based information about the likelihood of pregnancy and successful fetal outcome is not available. In this observational study of 16 195 female kidney transplant recipients aged 15-45 years in the United States between 1990 and 2003, we determined the pregnancy rate and live birth rate using Medicare claims data from the first three posttransplant years. The pregnancy rate was 33 per thousand female transplant recipients between 1990 and 2003 and progressively declined from 59 in 1990 to 20 in 2000. The live birth rate between 1990 and 2003 was 19 per thousand female transplant recipients and declined in parallel with the pregnancy rate. Despite a decrease in therapeutic abortions over time, the proportion of pregnancies resulting in fetal loss (45.6%) remained constant during the study due to an increase in spontaneous abortions and other causes of fetal loss. The pregnancy rate in kidney transplant recipients was markedly lower and declined more rapidly than reported in the general American population during the same period. The live birth rate was substantially lower than reported in voluntary registries of transplant recipients, and the proportion of pregnancies resulting in unexpected fetal loss increased over time.

Incidental atherosclerotic renal artery stenosis in patients undergoing elective coronary angiography: are these lesions significant?

BACKGROUND: Cardiologists often identify atherosclerotic renal artery stenosis (ARAS) during cardiac angiography. The importance of such 'incidental' ARAS (iARAS) is not known. The present study sought to describe renal perfusion using non-captopril (baseline) nuclear renograms in patients with iARAS, and to determine characteristics associated with a positive captopril renogram. METHODS: Patients presenting for non-emergent coronary angiography between June 2001 and February 2006 were angiographically screened for iARAS. Those with >50% stenosis of one or both renal arteries were referred to nephrology and underwent nuclear renography. RESULTS: 131 patients had renograms. The mean age was 73.2 +/-8.1 and median eGFR was 51.2 (40.0, 66.6) ml/min/1.73 m(2). 51% had evidence of reduced perfusion to one kidney, of which 13% were discordant with the angiographic lesion. 9% had positive captopril renograms. Captopril renogram positivity was associated with severe unilateral stenosis (p = 0.02). CONCLUSIONS: In cardiac patients diagnosed with iARAS, the presence of known anatomic lesions did not correlate with captopril renogram positivity. Uncertainty remains as to whether nuclear renography is a poor functional test in this population, or the lesions are not functionally significant. These results lead us to question both the significance of such lesions, and the utility of conducting renograms in this population.

Higher serum C-reactive protein predicts short and long-term outcomes in peritoneal dialysis-associated peritonitis.

We examined the association between C-reactive protein (CRP) and short- and long-term adverse outcomes in peritoneal dialysis (PD)-associated peritonitis. Serum CRP levels were measured at baseline and 3 weeks after initiation of treatment in 209 patients with an incident episode of peritonitis between 1 January 1999 and 31 March 2005. Patients were followed until 31 May 2005. Short-term adverse outcomes included switch to hemodialysis, death, persistent infection beyond planned therapy duration, and relapse; long-term adverse outcomes included a subsequent peritonitis event or death. After adjustment for age, gender, diabetes, duration of renal replacement therapy and causative organism, patients with higher CRP levels at diagnosis had a greater odds of an adverse short-term outcome (odds ratio 1.57 (95% confidence interval (CI): 0.61-4.02), 2.73 (95% CI: 1.09-6.87), and 3.38 (95% CI: 1.36-8.42) in the second, third, and highest quartiles). In patients who met criteria for resolution of peritonitis 3 weeks after diagnosis, those with higher CRP levels had a greater risk of a long-term adverse outcome (hazard ratio 1.79 (95% CI: 1.05-3.07)). In conclusion, higher levels of CRP are independently associated with adverse outcomes in PD-associated peritonitis. Serial measurement of this marker during the course of peritonitis may facilitate earlier identification of individuals at greater risk of complications.

Acidosis in a patient with cholera: a need to redefine concepts.

A patient presented with cholera and a severe degree of ECF volume contraction. Despite large losses of bicarbonate (HCO3-)-containing diarrhoeal fluid, laboratory acid-base values were remarkably close to normal. A detailed analysis emphasizing principles of physiology and a quantitative approach provided new insights and eventually better definitions of metabolic and respiratory acidosis. A shift in focus from HCO3- concentration to HCO3- content in the extracellular fluid (ECF) compartment revealed the presence of metabolic acidosis. Central to this analysis was an emphasis on the haematocrit to enable a more accurate estimate of the degree of ECF volume contraction. The latter also revealed 'contraction' metabolic alkalosis, which masked the underlying metabolic acidosis. The presence of a respiratory acidosis of the tissue type was evident from the raised venous PCO2, which was not surprising once the magnitude of the ECF contraction had been appreciated. 'Bad buffering', as defined by Professor McCance, was the immediate danger and prompted swift action to restore an effective circulation. The haematocrit and the venous PCO2 also contribute valuable information to monitor the response to therapy. Nevertheless, there were still dangers to be discovered when an in-depth analysis suggested that the administration of isotonic saline would introduce an unanticipated danger for the patient.