INVESTIGADORES
JOO TURONI Claudio Martin
congresos y reuniones científicas
Título:
Evaluación de disfunción endotelial y compliane arterial en flujo de antebrazo en pacientes en hemodiálisis
Autor/es:
MARAÑON RODRIGO; SANTOS JUAN; RISSO PATRÓN FACUNDO; JOO TURONI CLAUDIO; PERAL DE BRUNO M
Lugar:
Buenos Aires
Reunión:
Congreso; XI Congreso Argentino de HTA; 2004
Institución organizadora:
Sociedad Argentina de HTA
Resumen:
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 (Äpost-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
(Äpost-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