HEMODIALYSIS ARTERIOVENOUS ACCESS - A PROSPECTIVE HEMODYNAMIC EVALUATION

Background. Factors affecting: cardiac function in dialysis patients i nclude arterial blood pressure, anaemia, intravascular volume, and the arteriovenous (a-v) access. Cardiac failure has been directly attribu ted to dialysis a-v access in several cases. The contribution of the a -v access to cardiac performance has been tested, in the past, by a sh ort manual compression on the fistula, but this technique has obvious limitations. Methods. The present study examined prospectively the eff ect of dialysis a-v access on both cardiac function and various hormon al responses. Ten patients (age, mean+/-SD, 59.6+/-12.3) with end-stag e renal failure being prepared for chronic dialysis therapy were inclu ded. All patients underwent an echocardiographic study before and 2 we eks after the creation of the a-v access. Plasma atrial natriuretic pe ptide (ANP), plasma renin activity (PRA), and plasma aldosterone were measured at the same time periods. Results. Following the creation of the a-v fistula or graft, shortening fraction increased by 15.8+/-6.3% (P<0.01), stroke volume increased by 21.9+/-5.3% (P<0.01), ejection f raction increased by 10.6+/-4.5% (P<0.02), cardiac output increased by 19.0+/-6.9% (P<0.02), and cardiac index increased by 18.3+/-7.1% (P=0 .05). Systemic vascular resistance decreased by 23.5+/-7.1% (P<0.01). There was no change in blood pressure. heart rate, weight, haemoglobin or serum creatinine. ANP increased by 83.7+/-17.0% following the a-v access operation (P<0.001), PRA decreased by 41.2+/-10.0% (P<0.05), an d plasma aldosterone did not change. None of the patients developed ov ert high-output cardiac failure. Conclusions. This study shows that al least in the short term following the creation of a dialysis a-v acce ss, a mild state of volume overload develops, which is offset by the ' unloading' effect of the decreased peripheral vascular resistance; the latter is probably mediated by secretion of ANP in response to atrial stretching.