الفهرس 
Vascular Access Complications
Pulmonary HypertensionOnly 14 pages are availabe for public view
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Abstract
CKD is not an uncommon disease among population
worldwide. Once GFR deteriorates to a certain level, renal
replacement therapy becomes mandatory, that includes
either renal transplantation or more commonly
hemodialysis.
Hemodialysis imposes the need of an efficiently
functioning vascular access.
Native AVF still is the widely used vascular access
due to its longevity and decreased risk of morbidity and
mortality than other types of vascular access.
Even though native AVF still has many complications
that must be taken into consideration, one of them with the
most deleterious implication on the body generally and the
heart specifically is the High flow Access.
HFA implement harmful effect on cardiac structure
and functions increasing cardiovascular morbidity and
mortality.
Arteriovenous fistula decreases systemic vascular
resistance, causing increased stroke volume and cardiac
output in order to maintain blood pressure, and this can
cause left ventricular volume overload and eccentric left
ventricular hypertrophy. Although the chronic volume
overload caused by AVF induces structural and functional
changes on cardiovascular system. AVF has destructive effects on the cardiovascular system, such as left
ventricular hypertrophy, high-output cardiac failure, and
other symptoms of cardiovascular diseases, such as
hypertension and aortic stiffness. AV fistula flows greater
or equal to 2.0 L/min to result in high-output cardiac
failure.
Cardiovascular disease (CVD) is the leading cause of
morbidity and mortality in patients with End-Stage Renal
Disease (ESRD). This risk increases markedly in
population with HFA.
Flow in AVF exceeding 1500 ml/minutes is associated
with higher rates of complications.
Our study showed that proximal AVF associated with
more derioration of cardiac functions than distal AVF ,As
Cardiac output (CO) increases greatly and immediately.
This increase in CO is achieved by means of a reduction in
peripheral resistance, an increase in sympathetic nervous
system activity (increasing contractility) and an increase in
stroke volume and heart rate (HR) (Guyton etal., 1961).
Therefore, the presence of an AVF lowers systemic
vascular resistance resulting in an increase in stroke volume
(SV) and CO in order to maintain blood pressure (Girred et
al., 1996).
In our study we found that the proximal AVF cause
increase in SV, LVM and LVMI with normal RWT
(eccentric hypertrophy). The other relevant finding of our study is that in
patients with upper arm fistula there is highly statistically
significant increase in LVM, LVMI and decrease in EF
compared with lower arm fistula.
Our result can be explained as lower arm AVFs are
usually positioned in a type of patient with a different
phenotype from those who get an upper arm AVFs (among
them, usually there are less diabetics, younger people with
fewer vascular diseases and cardiac dysfunctions).