Background Cerebral and myocardial hypoperfusion occur during hemodialysis in adults. Pediatric patients receiving chronic hemodialysis have fewer cardiovascular risk factors, yet cardiovascular morbidity remains prominent. Methods We conducted a prospective observational study of pediatric patients receiving chronic hemodialysis to investigate whether intermittent hemodialysis is associated with adverse end organ effects in the heart or with cerebral oxygenation (regional O2 saturation [rSO2]). We assessed intradialytic cardiovascular function and rSO2, using noninvasive echocardiography to determine myocardial strain and continuous noninvasive nearinfrared spectroscopy for rSO2. We measured changes in blood volume and central venous oxygen saturation (mCVO2) were pre-, mid-, and post-hemodialysis. Results The study included 15 patients (median age, 12 years; median hemodialysis vintage 13.2 [9, 24] months were included. Patients were asymptomatic. The rSO2 did not change during hemodialysis, whereas mCVO2 decreased significantly, from 73% to 64.8 %. Global longitudinal strain of the myocardium worsened significantly by mid-hemodialysis and persisted post-hemodialysis. The ejection fraction remained normal. Lower systolic blood pressure and faster blood volume change were associated with worsening myocardial strain; only blood volume change was significant in multivariate analysis (β coefficient, -0.3; 95% confidence interval [95% CI], −0.38 to −0.21; P=0.0001). Blood volume change was also associated with a significant decrease in mCVO2 (β coefficient 0.42; 95% CI, 0.07 to 0.76; P=0.001). Access, age, hemodialysis vintage, and ultrafiltration volume were not associated with worsening strain. Conclusion s Unchanged rSO2 suggested that cerebral oxygenation was maintained during hemodialysis. However, despite maintained ejection fraction, intradialytic myocardial strain worsened in pediatric hemodialysis and was associated with blood volume change. The effect of hemodialysis on individual organ perfusion in pediatric versus adult patients receiving hemodialysis might differ.

Discrete subaortic stenosis (DSS) is a pediatric condition in which a fibrotic membrane forms within the left ventricular outflow track. The fibrotic membrane is removed surgically; however, there is a high rate of reoccurrence which requires a second surgery. There are currently no tools available to predict the risk of reoccurrence in DSS patients, a limitation addressed by this study. In this study, we analyzed resected fibrotic membranes for DSS patients at the time of first surgery for non-recurrent and recurrent patients, and at the time of second surgery for recurrent patients. RNA-sequencing was conducted to obtain a global screen of changes in RNA expression while mass spectrometry was used to obtain a global screen of changes in protein expression. The results from the RNA-sequencing and mass spectrometry provide valuable insight into genes and the proteins that are differentially regulated in recurrent vs non-recurrent DSS patients.

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