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G. Simonetti and F. Schaefer

Management of High and Low Blood Pressure in Dialysis Children. G. Simonetti and F. Schaefer Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University of Heidelberg, Germany. Hypertension in dialyzed children Hypotension during hemodialysis. Contents.

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G. Simonetti and F. Schaefer

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  1. Management of High andLow Blood Pressure in Dialysis Children G. Simonettiand F. Schaefer Pediatric Nephrology, Center for Pediatric and Adolescent Medicine, University of Heidelberg, Germany

  2. Hypertension in dialyzed children Hypotension during hemodialysis Contents

  3. Hypertension in dialyzed children Hypotension during hemodialysis

  4. Arterial hypertension is an important risk factor for cardiovascular diseases Long term survival of childhood - onset ESRD patients → depends on cardio/cerebrovascular diseases Background Oh et al. Circulation 2002;106:100-5

  5. Prevalence of hypertension in dialyzed children 3,743 pts in NAPRTCS: start 1 yr 2 yr Uncontrolled hypertension 56.9% 51% 48% Controlled hypertension 19.7% Normotensive 23.4% Risk factors for uncontrolled hypertension at follow-up: Baseline hypertensive, receiving antihypertensive medication Age <12 (highest in 0-1 yo)High interdialytic weight gainHigh serum phosphorusAcquired kidney disease Mitsnefes et al. Am J Kidney Dis 2005, 45:309-315Van De Voorde et al. Pediatr Nephrol 2007, 22:547-553

  6. Salt and water retention Plasma volume correlated with BP Strict enforcement of dry weight normalizes BP in most dialysis patients However, poor correlation of interdialytic weight gain and BP Renin-Angiotensin-Aldosterone System Normal levels despite hypervolemia Insuppressible by saline infusion Excessive local production by scarring renal tissues? Sympathetic hyperactivation Triggered by afferent signals from diseased kidneys Persistent on dialysis, post-Tx; normalized by Nephrectomy Stimulated by intrarenal Ang II; normalized by ACE inhibition Mechanisms of hypertension in CKD - 1

  7. Endothelial Factors Impaired endothelium derived vasodilation Accumulation of circulating NOS inhibitor ADMA Circulating Endothelin-1 elevated, correlates with BP PTH/Calcium PTH levels correlates with BP in 1° hyperparathyroidism PTH/elevated cytosolic calcium enhances pressor responses PTH suppresses eNOS expression Intrauterine Programming Barker/Brenner hypothesis: intrauterine malnutrition causes oligonephronia and programs for hypertension Mechanisms of hypertension in CKD - 2

  8. ABPM in children undergoing Dialysis • No correlations were found between ABPM and casual BP measurements, except for systolic day-time BP in PD patients • BP assessed by ABPM was higher in PD than in HD patients. The physiological decline of BP at night was significant and more pronounced in PD than in HD patients • Casual BP recordings are not representative of average BP in dialyzed pediatric patients • ABPM is useful in the diagnosis and treatment of hypertension in dialyzed children Lingens et al. Pediatr Nephrol 1995, 9:167-172

  9. “Reverse epidemiology” of BP-mortality relationship in adult HD patients ? Low blood pressure before dialysis seems to represent a risk for cardiovascular events But → Short follow-up of these studies → Patients with lower pressures may represent a sicker population (myocardial dysfunction, poor nutrition) Kalantar-Zadeh et al. Hypertension 2005, 45: 811-817

  10. Relative risk p Predialytic systolic BP 0.99 0.94 Predialytic diastolic BP 0.49 0.03 24h sytolic BP 1.37 0.09 Nighttime systolic BP 1.41 0.01 Nocturnal BP predicts cardiovascular death in adult hemodialysis patients Amar et al. Kidney Int 2000, 57:2485-2491

  11. Non-Dipping Predicts LV Hypertrophy and Cardiac Death in Hemodialysis Patients Liu et al Nephrol Dial Transplant 2003, 18: 563–569

  12. Control of volume status - discourage large interdialytic weight gains - control salt intake - control of ultrafiltration with blood volume monitoring (BVM) Prolonged and/or more frequent hemodialysis Adequate dialysis (Kt/V!)- sodium profiling Antihypertensive medications- only if elevated BP despite reaching dry weight Treatment of hypertension in dialyzed children

  13. Improved HD Patient Survival by Strict Volume Control Adult patients with better volume control (assessed by the cardio-thoracic-index, CTI) have a better survival compared to patients with a more pronounced overhydration. Ozkahya et al. Nephrol Dial Transplant 2006, 21: 3506-3513

  14. Improved blood pressure control with blood volume monitoring during hemodialysis A better control of overhydration was achieved with the use of BVM. At the end of the study a better blood pressure control was observed (ABPM). Patel et al. Clin J Am Soc Nephrol 2007; 2: 252–257

  15. Weekly Kt/V urea: 4.2  7.9 Serum phosphate: 1.87  1.28 Serum homocysteine: 21.6  13.4 Hemoglobin: 11.8  13.7 Epo dose: 83  59 Mean arterial pressure: 95  87 Interventricular septum: 10.9  6.8 Ejection fraction: 55  62 Short daily HDF 3*4h 5-6*3h Fischbach et al. Nephrol Dial Transplant 2004, 19: 2360–2367

  16. Only if blood pressure remains elevated despite the attainment of dry weight Agent preferably with a once per day dosing schedule (long acting drugs) Greater benefits with- ACE Inhibitors - Angiotensin Receptor Blocker Calcium Channel Blockers and β-Blockers→ probably not indicated in hemodialyzed children (vessels complicance ↓) Antihypertensive medications

  17. concurrent use of medication that raise BP renovascular hypertension polycystic kidney disease → consider nephrectomy noncompliance to medical regimen Refractory Hypertension

  18. Hypertension in dialyzed children Hypotension during hemodialysis

  19. During hemodialysis (fluid removal): Plasma refilling Passive venoconstriction Increase in heart rate and contractility Increase in arterial tone Impaired compensatory responses → hypotension Pathophysiology

  20. Factors causing arterial dilatation- antihypertensive drugs Paradoxical decrease in sympathetic activity Conditions associated with reduced cardiac refilling- left ventricular hypertrophy - diastolic dysfunction - structural heart defects Plasma refilling- if UF rates exceed refilling rates, the intravascular volume fall Factors contributing to arterial hypotension

  21. No antihypertensive drugs on dialysis days Avoiding food during dialysis Cooling dialysate Sodium profiling Discourage large interdialytic weight gains Control of fluid removal with BVM (Blood Volume Monitoring) (Midodrine) (Prophylactic caffeine administration) Preventing intradialytic hypotension

  22. Blood volume monitoring The control of blood volume (BVM) during hemodialysis was associated with less adverse events (hypotension). Hothi et al. Pediatr Nephrol 2008, 23: 813-820Jain et al. Pediatr Nephrol 2001 16: 15-18

  23. Hypertension in dialyzed children → most common cause: fluid overload ! Hypotension during dialysis → check for avoidable causes Conclusion

  24. Thank you for your attention

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