The relationship between the flow of arteriovenous fistula and cardiac output in haemodialysis patients.
ABSTRACT Satisfactory haemodialysis (HD) vascular access flow (Qa) is necessary for dialysis adequacy. High Qa is postulated to increase cardiac output (CO) and cause high-output cardiac failure. Aim of the present prospective study was to evaluate the relationship between Qa of arteriovenous fistulas (AVFs) and CO in order to have a closer insight into this scarcely explored aspect of HD pathophysiology.
Ninety-six patients bearing an AVF entered the study. All were evaluated a priori for the existence of cardiac failure according to the functional classification of the American College of Cardiology/American Heart Association task force. Qa and CO were measured by means of the ultrasound dilution Transonic Hemodialysis Monitor HD02.
The mean Qa of the 65 lower arm AVFs was 0.948+/-0.428 SD l/min, whereas that of the 31 upper arm AVFs was 1.58+/-0.553 l/min. The difference was statistically significant (P<0.001). Ten patients were classified as having high-output cardiac failure; seven of them bore an upper arm AVF. Thus, upper arm AVFs were associated with an increased risk of high-output cardiac failure (P<0.04, chi(2) test). A third-order polynomial regression model best fitted the relationship between Qa and CO. The analysis of the regression equation identified 0.95 and 2.2 l/min as Qa cut-off points. The receiver operating characteristic curve analysis showed that Qa values >or= 2.0 l/min predicted the occurrence of high-output cardiac failure more accurately than two other Qa values (sensitivity 89%, specificity 100%, curve area 0.99) and three Qa/CO ratio values (cardio-pulmonary recirculation-CPR). The better performance among the latter was that of CPR values >or= 20% (sensitivity 100%, specificity 74.7%, curve area 0.92).
Our prospective study shows that the relationship between Qa of AVFs and CO is complex and a third-order polynomial regression model best fits this relationship. Furthermore, it is the first study to clearly show the high predictive power for high-output cardiac failure occurrence of Qa cut-off values >or= 2.0 l/min.
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ABSTRACT: Creation of an arteriovenous fistula (AVF) for hemodialysis may result in cardiac failure due to dramatic increases in cardiac output. To investigate the quantitative relations between AVF flow, changes in cardiac output, myocardial stress and strain and resulting left ventricular adaptation, a computational model is developed. The model combines a one-dimensional pulse wave propagation model of the arterial network with a zero-dimensional one-fiber model of cardiac mechanics and includes adaptation rules to capture the effect of the baro-reflex and long-term structural remodelling of the left ventricle. Using generic vascular and cardiac parameters based on literature, simulations are done that illustrate the model's ability to quantitatively reproduce the clinically observed increase in brachial flow and cardiac output as well as occurence of eccentric hypertrophy. Patient-specific clinical data is needed to investigate the value of the computational model for personalized predictions.Medical & Biological Engineering 11/2012; · 1.76 Impact Factor
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ABSTRACT: Congestive heart failure is a well-recognized complication of hemodialysis arteriovenous fistula. Symptoms of dyspnea are usually associated with signs of congestive heart failure including pulmonary edema, pleural effusions, lower extremity edema, and liver enlargement, to name a few. We present a case of a gentleman with end-stage renal disease on chronic hemodialysis, which developed acute bilateral transudative pleural effusions in the absence of other signs of systemic venous congestion, associated with pulmonary venous congestion. We also discuss the pathogenesis and role of hemodialysis in management of this patient.Hemodialysis International 10/2012; 16 Suppl 1:S54-7. · 1.44 Impact Factor
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