P1729HEMODYNAMIC AND AUTONOMIC PERFORMANCE IN CHRONIC DIALYSIS AND RENAL TRANSPLANT PATIENTS. IS THERE AN IMPROVEMENT?

Background and Aims

Chronic kidney disease (CKD) is a major public health problem, with high prevalence worldwide. It’s associated with high morbidity and mortality, especially in the advanced stage when substitution therapies are needed. It’s well established that Ps with end-stage kidney disease have increased mortality due to an elevated incidence of cardiovascular diseases (CVD). The best treatment for this population it’s definitely the kidney transplant (KT), mostly because it improves the quality of life and reduces global and CV mortality compared with Ps treated with chronic dialysis (Dx). There is not a convincing explanation about the physiological mechanisms involved in this improvement. Impedance cardiography (IC) it’s a well established, validated method to asses hemodynamics parameters.

Study and describe the differences between hemodynamic and autonomic profiles between KT and Dx Ps using IC.

Method

We studied 331 Ps as part of a cardiovascular evaluation program in Ps with ESKD which is being carried out in our institution (CEMIC, Buenos Aires). Of these, 190 were on Dx and 141 on KT. Non-invasive hemodynamic assessment was performed using IC (Z Logic- Exxer SA) in supine and standing position, taking into account the following variables: heart rate (HR), thoracic fluid content (TFC), stroke volume (SV), systemic vascular resistance index (SVRI), arterial compliance index (ACI), and pre-ejection period (PEP). Ps in the Dx group were studied on the interdialytic day. We evaluated the autonomic profile by studying the variability of HR (Kubios Finland) for three minutes, with measurements of the spectral components, high frequency (HF), low frequency (LF), total power (totpowar) and the ratio LF/HF. We compared absolute supine variables and then the differences between supine and standing positions. Exclusions criteria: less than six months of KT or Dx; incomplete basic hemodynamic study or lack of data; amputation; previous KT.

Results

We included 107 Ps of Dx and 118 of KT. No significant differences were detected in terms of age, sex, diabetes, and antihypertensive treatment. Ps on Dx had more prevalence of hypertension and CVD. Those in KT group had a median time of 72,5 months of transplantation and 46 months of prior dialysis time, with a media of eGFR (CKD-Epi) of 56 ml/min/1,72 m2. Ps on Dx had a median of 22 months on substitution treatment. The hemodynamic evaluation showed that KT Ps had lower HR (p=o,oo1), higher ACI (p=0,002) and PEP (p=0,05), and a tendency of higher SV (p=0,07). The autonomic evaluation showed no significant differences between the two groups, though the totpowar had a tendency to be higher in the KT group with a median of 367(200-625) compared with 248 (103-465) in the Dx group (p=0,07). The changes in the variables during the standing position evidenced that Ps on Dx had a lower elevation of HR (p=0,04) and SVRI (p<0,001). We assessed the prevalence of orthostatic hypotension defined as a reduction of the SBP in 20 mmHg and/or the DBP in 10 mmHg after standing up. The Dx group had a prevalence of 30% and the KT group of 20%, but the difference was not significant.

Conclusion

Ps with KT seems to have a better hemodynamic profile than those on Dx, mainly, a better vascular response with a more physiological- compensatory elevation of HR and VSRI when they stand up. Although the autonomic activity showed no significant statistical difference, the total power, an expression of the whole autonomic activity, showed us a clear tendency in favor of KT, which needs to be confirmed with a larger size sample.