Collaborative Brazilian Pediatric Renal Transplant Registry (CoBrazPed-RTx): A Report From 2004 to 2013.

BACKGROUND: The Collaborative Brazilian Pediatric Renal Transplant Registry started in 2004 as a multicenter initiative aiming to analyze, report, and share the results of pediatric kidney transplantation in Brazil. Data from all pediatric kidney transplants performed between January 2004 and December 2013 were recorded electronically and periodically updated. All patients under 18 years old from the participating centers were enrolled. Demographic data, etiology of chronic kidney disease, and patient and graft survival were analyzed. From a total of 2443 pediatric kidney transplants performed in Brazil during the study period, we report data from 1751 pediatric renal transplants performed in 13 centers enrolled in the collaborative study. Median age at transplantation was 12.4 years, and most of recipients were male (56%). The most common underlying renal etiologies were obstructive uropathy (31%) and glomerulopathy (26%). METHODS: According to donor source, 1155 (66%) of transplants were performed with deceased donors (DD). Initial immunosuppression consisted mainly of tacrolimus, mycophenolate, steroids, and induction therapy with anti-IL-2R antibodies. RESULTS: One-year graft survival (death-censored) was 93% and 90% (log rank test, P < .01), respectively, for living donor (LD) and DD. Graft losses (15%) were most frequently caused by vascular thrombosis, chronic allograft nephropathy, death with functioning kidney, acute rejection, and recurrent renal disease. Recipients of DD had 2.02 (95% confidence interval: 1.14-3.59) times the hazard of graft loss compared with those of LD (P = .015). Patient survival rates at 1 and 5 years were 98% and 97% for LD and 97% and 93% for DD, respectively. The mortality rate was 3.8%, mainly as the result of infection and cardiovascular disease. CONCLUSIONS: The results of this collaborative pediatric transplant study are comparable to international registries. Our effort has been able to maintain an exchange of information, both among the participating centers and with other international registries.

Wavelet analysis of autonomic outflow of normal subjects on head-up tilt, cold pressor test, Valsalva manoeuvre and deep breathing.

Non-invasive autonomic evaluation has used fast Fourier transform (FFT) to assign a range of low (LF) and high frequencies (HF) as markers of sympathetic and parasympathetic influences, respectively. However, FFT cannot be applied to brief transient phenomena, such as those observed on performing autonomic tests where the acute changes of cardiovascular signals (blood pressure and heart rate) that represent the first and most important stage of the autonomic performance towards a new state of equilibrium occur. Wavelet analysis has been proposed as a method to overcome and complement information taken exclusively in the frequency domain. With discrete wavelet transform (DWT), a time-frequency analysis can be done, allowing the visualization in time of the contribution of LF and HF to the observed changes of a particular signal. In this study, we evaluate with wavelets the acute changes in R-R intervals and systolic blood pressure that are observed in normal subjects during four classical autonomic tests: head-up tilt (HUT), cold pressor test (CPT), deep breathing (DB) and Valsalva manoeuvre (VM). Continuous monitoring of ECG and blood presure was performed. Also LF, HF and LF/HF were calculated. Consistent with previous interpretations, data showed an increase of sympathetic activity in HUT, CPT and VM. On DB, results reflected an increase in parasympathetic activity and frequencies. In conclusion, when compared with FFT, wavelet analysis allows the evaluation of autonomic variability during short and non-stationary periods of time and may constitute a useful advance in the assessment of autonomic function in both physiological and pathological conditions.