ACUTE EFFECT OF HEMODIALYSIS ON ENDOTHELIAL FUNCTION AND ARTERIAL COMPLIANCE IN ANTEBRACHIAL FLUX IN PATIENTS WITH KIDNEY FAILURE

SANTOS JUAN,; MARAÑON RODRIGO; JUAN SALINAS; JOO TURONI CLAUDIO; BARRANCO CARLOS; COVIELLO ALFREDO; PERAL DE BRUNO

La Habana CUBA,

Congreso; IX Congreso Centroamericano y del Caribe de Nefrología e Hipertensión; 2005

Sociedad Latinoamericana de Nefrología

We previously developed a non invasive impedancimetric method to evaluate by reactive hyperemia (RH) endothelial function (EF) in patients with coronary disease. Endothelial nitric oxide (NO) and its capacity to relax smooth arterial muscle, altered in vascular pathologies would be involved in a diminished RH. Recently was proposed the use of the rigidity index (RI) in order to discriminate arterial compliance. RI is determined beginning with the dichrotic notch (catachrotic/anachrotic wave). Objective: To determine the degree of EF and RI in hemodialyzed patients and if these parameters are altered during the dialysis sessions. Method: The impedancimetric method consists in applying a low intensity current through surface electrodes on the forearm, the signal is digitalized and processed in a PC. Sample: Group of ambulatory patients with with kidney failure submitted to hemodialysis (PG n=17). Control group (CG n=22) young adults of either sex without known vascular pathology. RH (difference of pulse wave pressure trough-peak:t-p) and RI, before and after 5 min total arterial occlusion, were measured. Values obtained (mean±SEM) were compared in postocclusion and preocclusion apnea (Dpost-pre). Electrocardiogram in bipolar lead II was registered simultaneously. Intradialysis measurements were performed after 1 hour of beginning. Statistical analysis was performed with software Statistical 5.0. Results: Preocclusion t-p relation was greater in CG than in PG (0.37±0.08 n=16 vs 0.21±0.06 volts, n=16, p<0.001). An increase in the relation t-p (Dpost-pre=22.8±7.9 %, p<0.01) after occlusion was observed only in CG. HR induced a significant decrease of RI only in CG (RIpost: 45.0±4.2, n=14 vs RIpre: 70.4±8.0, n=11, p<0.001). Preocclusion intradialysis t-p was similar to the predialysis one, without differences in t-p after occlusion in any cases. Similar preocclusion RI values were obtained in intradialysis and predialysis, however RI were significantly increased (RIpre: 70,4±8.8, n=10 vs RIpost: 83.4±9.0, n=11 p<0.04) in postocclusion intradialysis. Conclusion: Impedancimetry was effective measuring RH. In PG generalized vascular dysfunction was found. In CG, hyperemic response obtained and the low RI are explained by endothelial presence, NO release and a good muscular function. Absence of changes in t-p relation in PG would be directly related to deficient EF. Low values of t-p preocclusion observed in PG would indicate that volume overload may be an additional negative factor to take into account during evaluation of RI, but not in the EF evaluation. This fact is supported by the RI increase only in intradialysis postocclusion. Here, we discriminate for the first time in hemodialyzed patients, an endothelial and myogenic altered response. Furthermore, hemodialysis “per se” would exacerbate arterial rigidity.