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ANNA Presentation Abstracts
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[SU-PO363] Cardiac Output
(CO) Monitoring during Haemodialysis (HD)  a Comparison between Saline
Dilution Method (Transonic), and a Noninvasive Method Based on Rebreathing of Inert Gas (Innocor).
Danny Jensen,
Jens Dam Jensen. Dept. of Nephrology C, Skejby, Aarhus University Hospital,
Aarhus,
Denmark
Monitoring of CO during haemodialysis (HD) is of
great interest, due to the cardiovascular effects of HD. Innocor
(I) is a new, non invasive portable device for assessing CO with built in pulse
oxymeter and multigas analyser. The device does all analyses of gas automatically
on site. The gasses used in the I device are: Sulfurhexaflouride
(SF6) 0,1% (measures lung volume) and N2O
0,5 % (measures pulmonal blood flow) and O2 25%
(variable). We compared CO measurement by I with
Transonic (T) in a controlled trial in which the sequence (T or I) was randomised. Twentyfive (m/f =
18/7) stable chronic HD pts age mean = 54(24  79)
y were investigated. Dry weight = 68(42 - 96) kg. Mean patient access flow was
1110  134(360
2775)
ml/min. Dialyser blood flow rate = 289  10
(192 404)
ml/min. Mean Hct = 0,38 (0,31-0,46). Mean O2
uptake = 0,21 0,087
(0,08-0,49) L/min. Pulmonal shunt fraction = 8 8,4
(0 41)
%. All patients had stable A-V arm fistula with no local fistula recirculation.
We found a CO T = 5,9 0,35(3,9
- 10,5) L/min. CO I = 4,9 0,34(1,8
- 9,2) L/min. Mean delta CO (T I)
= 1,0 0,2(1,4
- 0,6) L/min (p< 0.001). The measurement repeatability of both methods
showed an identical coefficient of variance (sd/mean
CO), CVT = 6%, CVI = 7% in both high and low CO levels.
Pearson s
linear correlation coefficient (COT vs. COI) = 0,84 (p<0.001). A linear regression showed COI
= 0,99*COT1
(r2 = 0,7). Nine (36 %) of our observations on delta CO were within 15%
limits of agreement in a Bland - Altman plot.
Access flow in % of CO correlated significantly with delta CO, Spearman rho = 0,68 (p<0,01).
Conclusion: We found a clear relationship between CO measured with T and I. Both demonstrated reproducible results. The I underestimates CO compared with T. This may be due to rapid
recirculation of N2O through the A-V fistula with interference of
pulmonary test gas exchange. The association between the difference in CO
measured by T vs. I - and access flow in % of CO supports this hypothesis.
Sunday, October 31, 2004 , 10:00 AM
Poster:
Cardiovascular Disease in Dialysis: Clinical Aspects (10:00 AM - 12:00 PM) Poster Board Number:
SU-PO363
[SU-PO368] Blood Flow in Brachiocephalic AVF Represents a Greater Percentage of
Cardiac Output Than That in Radiocephalic
AVF.
Wama van der Mark, P.
Boer, P.J. Blankestijn. Department of Nephrology, University Medical
Center Utrecht,
Utrecht, Netherlands
The flow in the arteriovenous (AV) access of hemodialysis patients means an
extra burden to the cardiac output (CO) and is therefore a risk factor for left
ventricular hypertrophy and heart failure. The aims of this study were to
quantify access flow and to assess the percentage of CO that passes through the
access and to compare the different types of accesses in this respect.
During a single hemodialysis session both CO and access flow were quantified by
the Transonic indicator dilution technique.
We performed 78 sets of measurements; 35 in AV fistulae forearm (radiocephalic), 29 in AV fistulae upper arm (brachiocephalic), and 14 in forearm PTFE grafts (in all
cases from brachial artery to cephalic vein).
In forearm AV fistulae, upper arm AV
fistulae and PTFE grafts, CO (meanse) was 5351315 mL/min, 6541364 mL/min and 4661349 mL/min (p<0.01 upper arm AV fistulae versus
others). Access flow was 966114 mL/min, 1693143 mL/min and 71577 mL/min (p<0.001 upper arm AV fistulae versus
others). Access flow represented 16.91.3%,
26.72.1%
and 15.51.4
% of CO. The percentage in upper arm AV fistulae was significant higher
(p<0.05) than in the two other groups. Blood pressure during measurements
did not differ between groups, indicating that vascular resistance in the arms
of patients with upper arm AV fistulae was lower than that in the other two
groups.
In conclusion, both in absolute terms and relative to CO flow in upper arm AV
fistulae is higher than in forearm AV fistulae and PTFE grafts. This is a
result of the lower vascular resistance in the arms of these patients. High CO
may mean an additional cardiovascular risk factor. The results underscore the
preference for radiocephalic AV fistulae over brachiocephalic AV fistulae as primary choice for vascular
access.
Sunday, October 31, 2004 , 10:00 AM
Poster: Cardiovascular
Disease in Dialysis: Clinical Aspects (10:00
AM - 12:00 PM) Poster Board Number: SU-PO368
|
[SA-PO309] High Flow
Fistula and Cardiac Hemodynamics.
Jennifer
M. MacRae, Thuan H. Do,
Debbie Rosenbaum, Adeera Levin, Mercedeh Kiaii.
Nephrology and Internal Medicine, University
of British Columbia, Vancouver, BC,
Canada
AVF creation is associated with a decrease in peripheral resistance and
increased cardiac output (CO). High output cardiac failure (HOCF), a rare
complication of high flow AVF, is defined as symptoms of CHF in the presence
of a high cardiac index (
3.0 L/min/m2). This study was to determine the prevalence of high flow AVF,
to document pt and AVF characteristics associated with high flow, and to
compare hemodynamic and echo parameters of high and normal AVF flow pts.
High access flow, Qa, was defined as > 2.0 L/min
10%
and normal Qa as 600 1500
ml/min. Qa, CO, central blood volume (CBV) and
total peripheral resistance (TPR) were measured in duplicate using ultrasound
dilution technique (HD02 Monitor Transonic Inc.) on the mid week dialysis run
in chronic stable HD pts. Echo was performed on the same day
.
19 % (46/242) of the AVF population had Qa>
2.0L/min. We report the results on 21 patients with high Qa
and 15 with normal Qa. High Qa
is associated with a younger age (55y vs 73y,
p<0.05), upper arm AVF (p=0.059), hx of a
previous AVF(p<0.05) and a higher PTH level.
Table 1 shows the hemodynamic and echo data for the
two groups.
Both CO and Qa/CO ratios are significantly higher
in the high Qa pts. In these pts we do not know the
overall risk of CV outcomes or at which degree of Qa
or Qa/CO this may occur. Prospective monitoring of Qa/CO in high flow pts is necessary to better understand
their potential cardiac risk and to develop intervention strategies.
|
|
BP mmHg
|
CO* L/min
|
TPR*
|
Qa* ml/min
|
Qa/CO*
|
LVMI
|
LVEF %
|
|
Normal Flow AVF (15
pts)
|
135/70
|
5.0(4.4-5.7)
|
17.8(16-20)
|
925(660-1110)
|
16(13-25)
|
102(93-142)
|
65(65-70)
|
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High Flow AVF (21 pts)
|
143/76
|
8.1(6.5-14.8)
|
12.5(11-15.3)
|
2260(2100-3750)
|
32(26-38)
|
122(114-149)
|
65(60-65)
|
*p<0.05
Funding Source: Kidney Foundation of Canada
Saturday, October 30, 2004
, 10:00 AM
Poster:
Managing Hemodialysis Access Failure (10:00
AM - 12:00 PM) Poster Board Number: SA-PO309
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[PUB239] Variation of
Hemodynamic Parameters during Hemodialysis Assessed by the Transonic Flow
Method.
Jens-Uwe
Kriete, Bernd Sucke, Werner
Riegel. Medizinische Klinik III, Klinikum Darmstadt, Darmstadt, Germany
Cardiovascular diseases are the leading cause of mortality in end stage renal
disease patients. Hypotensive episodes during hemodialysis have a major adverse
impact on the survival rate of hemodialysis patients. The main hemodynamic
compensatory mechanisms in patients undergoing dialysis are largely unknown.
The aim of this study is to investigate the intradialytic
stability of dialysis patients by measuring hemodynamic parameters. Cardiac
Output (CO), Cardiac Index (CI) and Peripheral Resistance (PR) are assessed by
means of Transonic Hemodialysis Monitor HD02.
We monitored CO, CI and PR every hour during dialysis sessions using Transonic
Hemodialysis Monitor HD02 (Diatec GmbH, Gilching, Germany).
Eleven stable patients who had been on renal replacement therapy for more than
one year were investigated. The achievement of dry body weight after dialysis
was assessed by ultrasound examination of the vena cava.
Data are given as mean SD.
Nine patients showed a decrease in CO (1.38, 0.75
l/min) and CI (0.73, 0.35)
and a parallel increase in the PR (6.56, 3.1
mmHg/l/min). The ultrafiltration rate of each patient varied between 362.5 ml/h
and 1300 ml/h. The ultrasound investigation of the vena cava after dialysis
showed inspiratory collapse in these 9 cases. We did
not detect blood recirculation in the vascular accesses of any patient. We
noticed an increase in the CO (1.35 l/min), CI (0.85) and a decrease of the PR
(4.55 mmHg/l/min) in 2 patients. A collapse of the vena cava was not observed
in these cases.
The Transonic Monitor HD02 is a convenient device for monitoring cardiovascular
parameters during dialysis. Patients who attained their dry body weight after
dialysis showed a moderate decrease in cardiac output and cardiac index and a
related increase in the peripheral resistance. These findings were not
correlated to the ultrafiltration volume. The observed increase in cardiac
output and cardiac index in patients who do not reach their dry body weight
could be interpreted as an improvement of heart function due to recompensation of fluid homeostasis.
Disclosure - Grant/Research Support: Fresenius Medical Care AG, Bad Homburg, Germany
Publication Only
[F-PO403] Monitoring of Dialysis Access
by Transonic Flow Studies Is Operator Dependent.
Jeffrey I. Silberzweig, Kathryn Osborn, Yvonne Noak.
Hemodialysis, The Rogosin Institute, New York, NY;
The Division of Nephrology, Weill Medical College of
Cornell University, New York, NY
Reductions in flow lead to subtle often unrecognized compromises in delivery of
dialysis and presage failure of the access device itself. Access flow can
therefore be considered a fundamental property of the access that should be
monitored1. K/DOQI guidelines call for surveillance of AV grafts by
intra-access flow and referral for fistulogram if the flow is less than 600 mL/min or there is a decrease in flow by more than 25% over
4 months2.
We initiated an intra-access flow monitoring program using the Transonic monitor in May 2002. Our program aimed to increase
the sensitivity of the test by using a cutpoint value
of a 10% decline in flow over one month. Between January 2002 and April 2004
(excluding January 2003 and February 2004), 1508 Transonic studied were done.
Of these, 239 showed at least 10% decline in flow from readings obtained one
month earlier. Of these, 127 were referred for angiograms; 127 (100%) patients
had abnormal stenotic abnormalities requiring percutaneous transluminal
angioplasty (PTA). Among the 1269 patients with normal studies, 4 (0.32%) had a
graft thrombosis. These data indicate a sensitivity of 96.95% and a specificity
of 100%.
The success of our monitoring program led to a dramatic reduction in dialysis
graft thromboses. Patients profited by a marked reduction in the need for
dialysis access via femoral catheterization. During the six months prior to
initiating the monitoring program, 17 patients required femoral catheterization
for access thromboses; two years later, only 2 such procedures were done.
References:
1. Depner, TA, et.al., ASAIOJ, 541, 1995, 745.
2. National Kidney Foundation, AJKD, 37 Suppl.,
2001, S150
Friday, October 29, 2004 , 10:00 AM
Poster: Hemodialysis Access
Failure (10:00 AM - 12:00 PM)
Poster Board Number: F-PO403
[SU-PO270] Cardiovascular
Stability of Intermittent  Single Pass
Batch Dialysis
a
Prospective Study Using the Transonic Flow Method.
Bernd Sucke,
Jens-Uwe Kriete, Werner Riegel. Medizinische Klinik III, Klinikum Darmstadt, Darmstadt, Germany
 Single
Pass Batch Dialysis
(Genius) is a successfully established renal replacement technique in end stage
renal disease patients. It is supposed to be associated with less severe
decline in blood pressure and lower increase of pulse rate compared to
conventional hemodialysis.
This study compares the intradialytic hemodynamic
changes in patients undergoing Genius dialysis and conventional intermittent
hemodialysis.
Ten patients (3 women, 7 men) received alternating intermittent Genius dialysis
and conventional hemodialysis (Fresenius 4008, each Bad
Homburg, Germany) randomly.
Patients had been on chronic renal replacement therapy for more than one year.
Cardiac Output (CO), Cardiac Index (CI) and Peripheral Resistance (PR) were
monitored once an hour during the dialysis session. Measurements were performed
by the Transonic Flow method (Diatec GmbH, Gilching, Germany) using a hemodilution technique. Prior to dialysis a recirculation
in the vascular access was excluded. The achievement of dry body weight after
dialysis was controlled by ultrasound investigation of the inferior vena cava.
Data are given as mean SD.
Eight patients showed a decrease in CO (F4008 vs
Genius: 1.21 0.59
vs1.3 0.69
l/min), CI (0.66 0.3
vs 0.71 0.39)
and an increase in PR (5,77 2.28
vs 5,53 3.95
mmHg/l/min) at the end of the dialysis session. These 8 patients achieved their
dry body weight at the end of dialysis. Two patients showed an increase in CI
and a decrease in PR during conventional dialysis. Both patients failed to
attain their dry body weight. Remarkably, 4 patients showed a transitory
decline in PR (2 1.08
mmHg/l/min) after starting Genius dialysis session.
Focussing on cardiovascular stability, intermittent
Genius dialysis seems to be an appropriate alternative to conventional
dialysis. There are no significant differences of the hemodynamic parameters
during dialysis comparing both techniques of renal replacement therapy when dry
body weight at the end of dialysis was achieved. The transitory decline of the
PR in 4 patients receiving Genius dialysis may be explained by the contact of
blood to warm dialysate at the beginning of the treatment.
Disclosure - Grant/Research Support: Fresenius Medical Care AG, Bad Homburg,
Germany
Sunday, October 31, 2004 , 10:00 AM
Poster: Hemodialysis: Body
Composition and Hemodynamics (10:00 AM - 12:00 PM)
Poster Board Number: SU-PO270
|
[F-PO398] Myths and
Realities of Vascular Access Surveillance Programs during Hemodialysis (HD).
Nikolai
M. Krivitski. Engineering, Transonic Systems
Inc., Ithaca, NY
Since the introduction of intra-access pressure and flow measurement
techniques, a large body of literature on access surveillance has been
produced. Recently, the efficacy of access surveillance has been debated. The
purpose of this abstract is to summarize papers on access surveillance
techniques with respect to the ability to identify stenosis and thrombosis.
Criteria for inclusion: 1) papers from peer-reviewed journals or books (no
abstracts); 2) independent studies only--papers by authors and companies that
invented the surveillance technology were not included. Results are presented
in the Table.
|
Summary of results of vascular access surveillance trials
|
|
Surveillance
|
Dynamic venous pressure
|
Static venous pressure
|
Access flow during HD
|
|
Independent studies
|
10
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7
|
22
|
|
Number of accesses
|
AVG=748 AVF=150
|
AVG=353 AVF=84
|
AVG=1501 AVF=1246
|
|
Investigated stenosis
|
positive=4* negative=1*
|
positive=3* negative=0*
|
positive=11*
negative=0*
|
|
Investigated thrombosis
|
positive=4* negative=6*
|
positive=2* negative=4*
|
positive=12*
negative=5*
|
|
Major problems with
some studies and technologies
|
Wrong basic theoretical
assumption
|
Wrong basic theoretical
assumption
|
Not following both
K/DOQI threshold guidelines; PTA failure
|
* authors
conclusions on surveillance outcomes; only papers included-no abstracts; some
studies had both positive and negative conclusions on stenosis and/or
thrombosis.
Among 10 studies that used only one flow threshold, a positive conclusion was
reached in 7 studies and a negative conclusion was reached in 3 studies.
Among 12 studies that used both absolute and trended access flow thresholds
(analogous to the K/DOQI guidelines), 10 had positive conclusions about flow
surveillance and stenosis detection or thrombosis prediction. Two presented
negative conclusions--one identified PTA failure, and the other had results
that are in dispute.
The summary of 17 independent intra-access pressure clinical studies does not
support the statement that static pressure is a better surveillance tool than
dynamic venous pressure. Analysis of 22 access flow studies shows that it is
more efficacious to use both absolute and trended thresholds, as promoted by
the K/DOQI guidelines, to achieve positive outcomes.
Scientific Advisor: Employee of Transonic Systems
Inc.
Friday, October 29, 2004
, 10:00 AM
Poster:
Hemodialysis Access Failure (10:00
AM - 12:00 PM) Poster Board Number: F-PO398
|
[SU-PO275] Hemodynamic Stability during
Pre-HDF and Lowflux HD at Temperature Controlled
Conditions Using High Calcium-Ion Dialysis and Replacement Fluid. A Blinded
Randomized Controlled Study.
Danny Jensen, Nikolaos Karamperis, Jens D.
Jensen. Dep. of Nephrology C, Skejby, Aarhus University Hospital,
Aarhus,
Denmark
Convective therapy is thought to result in better hemodynamic stability than
conventional low flux hemodialysis (HD). We compared HD with high dose pre-hemodiafiltration (HDF) in 13 dialysis patients (pts), mean
age 49 y (26-76). Pts with NYHA > II were excluded. Pts were randomized to
either HD followed by pre-HDF (4
h) or vice versa. The dialysis modality was blinded. Substitution fluid volume
in HDF was 1,2 L/kg dry weight (83 2L).
Ca-ion fluid concentration was 1,75 mM. Arterial temperature (atmp)
was locked at pt temp. at dialysis start. Cardiac
output (CO) was measured hourly during the sessions using the Transonic Flow QC
saline dilution method.
Mean blood pressure (MBP) change during HD (end vs. start) was -0,52 2,6
mmHg (ns) and -2,8 3,1
mmHg (ns) during HDF. MAP decrease HD vs. HDF (ns). CO decreased during HD from
6,9 0,5
L/min to 6,1 0,44
L/min (p<0,05) and during HDF from 7,4 0,24
L/min to 5,9 0,52
L/min (p<0,01). CO decrease in HD vs. HDF (ns). The stroke volume (SV)
during HD declined 5 6
mL (ns) and 14 6
mL (p<0.05) in HDF. SV decline HD vs. HDF was 10 6
mL (ns). Total periferal
resistance (TPR) increased in HD by 2,2 1,2
mmHg min/L
(ns) and in HDF by 2,8 0,7
mmHgmin/L
(p<0,01). The differences in TPR increase in HD vs
HDF was 0,6 1,1
mmHgmin/L
(ns). Pulse rate (P) during HD decreased 6 2
bpm (p<0,05) and 3 5
bpm (ns) during HDF. Diff. in P decreases between
modalities (ns). Energy loss (cooling) during HD = 228 41
kJ and during HDF = 207 40
kJ (ns). The atmp was kept constant 36,6 0,1 C
in HD and 36,5 0,1C
in HDF. Ultra filtration (UF) was 3,3 0,4
kg in HD and 3,1 0,2
kg in HDF. Decrease in blood volume HD=10 1%
in HD and 11 1%
in HDF. Kt/V in HD was 1,6 0,1,
and 1,8 0,1
in HDF.
In conclusion, a decrease in SV during HDF in high calcium
treatment at temp. controlled, UF and Kt/V
matched conditions was found. CO decreased equally in both modalities. MBP did
not decrease significantly in any modality. TPR increased only during HDF, and
no TPR difference between HD and HDF could be demonstrated.
Sunday, October 31, 2004 , 10:00 AM
Poster: Hemodialysis: Body
Composition and Hemodynamics (10:00 AM - 12:00 PM) Poster Board Number: SU-PO275
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[F-PO399] How Well Does
Access Blood Flow (Qa) or Decreases in ABF ( Qa) Predict Arteriovenous
Graft (AVG) Thrombosis?
Brian
M. Murray, Neeraj Singh. Medicine, University at
Buffalo, Buffalo, NY
Access surveillance with Qa or Qa has been recommended by DOQI to prolong AVG survival ,
but it,s utility for this purpose has been
challenged (Paulson, AJKD35: 1089, 2000). We conducted a prospective
non-interventional study in which 43 patients with functioning AVGs had Qa (by Transonic HD02
meter) measured on 3 occasions, 1 month apart, and were then followed for a
further 6 months (without further Qa measurements).
Five patients were excluded from the analysis ( 1
AVG clotted before the second measurement, 2 missed Qa
measurements due to hospitalization, 2 underwent fistulograms(with
angioplasty) for clinical indications). None of the other 38 AVGs had any intervention during the 6 month study period
except for AVG thrombosis. There were 7 episodes of thrombosis (18%). We
compared the ability of either a Qa < 600ml/min,
a Qa >20%, the presence of both
criteria or either criterion to predict thrombosis over a 6 month
follow-up period. Table 1 shows the sensitivity, false positive rate and
post-test probability of thrombosis for each testing criterion.
|
Predicting thrombosis within 6 mos
|
|
Criterion
|
Sensitivity
|
False positive rate
|
PostTest Probability after a PTR
|
PostTest Probability after a NTR
|
|
Qa <600
|
57%
|
19%
|
50%
|
10%
|
|
Qa>20%
|
86%
|
13%
|
59%
|
3%
|
|
Either
|
86%
|
29%
|
39%
|
4%
|
|
Both
|
50%
|
9%
|
55%
|
18%
|
PTR=positive test result,NTR=negative
test result
It can be seen that Qa performed the best with a sensitivity of 86% and a
false positive rate of only 13%, values that would meet those recommended by
Paulson. If the presence of either a Qa<600 or Qa >20% were used then there was no improvement in
predictive ability because of the increase in false positive rate to 29%.
This may have been due to inclusion of patients with low but stable Qa that did not thrombose. On
the other hand, requiring that both criteria be satisfied resulted in a
decrease in sensitvity (to 50%) with only a minimal
improvement in the false positive rate (9%). These data support the proposal
of Neyra et al. (KI 54:1714, 1998) that a decrease in Qa
may be the best predictor of intermediate term graft thrombosis.
Friday, October 29, 2004
, 10:00 AM
Poster:
Hemodialysis Access Failure (10:00
AM - 12:00 PM) Poster Board Number: F-PO399
|
[PUB195] Clinical Evaluation
of Blood Flow Direction in Hemodialysis Graft Protheses.
Roman Fiedler, Matthias Pfau, Bernd Osten, Thomas Langer.
Department of Nephrology, Martin-Luther-University Halle-Wittenberg,
Halle (Saale), Germany;
Department of Internal Medicine, St. Elisabeth and St. Barbara Hospital Halle, Halle (Saale),
Germany
The trouble-free use of hemodialysis (HD) shunts is the absolute need for an
effective dialysis treatment. Especially in graft loops the confusion of blood
flow direction (BFD) with following recirculation can not be excluded in
clinical practice, if surgical report is not available. The aim of this study
was to prove a simple clinical method for the evaluation of BFD in HD graft protheses.
Forty-seven HD patients, aged 61 [range: 30-80] years, with a graft prothesis were recruited. The mean dialysis duration of the
patients was 68 [range: 2-253] months, and the graft prothesis
types were Loops
(78,7 %), Straights
(14,9 %), and Colliers
(6,4 %). We investigated for the determination of BFD the simple but safe
clinical method of auscultation prior to shunt puncture and compared it to HD01
(Transonic Inc., USA),
a conventional ultrasound hemodilution method during
HD.
In all grafts blood flow as well as recirculation were
measured by HD01,
and so BFD was fixed. The shunt noises, which were auscultated
by stethoscope (n=47) and recorded as wave file by a microphone computer system
(n=32), showed a characteristic stenosis effect by finger press on the graft
flow upwards, whereas the noises were scarcely changed by finger press on the
graft flow down. Clinical evaluation of BFD was correct in 88 %, impossible in
10 % of the cases and wrong in 1 patient. The study also verified that in 6
patients (12,8 %) dialysis blood tubes were connected
always contrary to BFD in the graft. The determined mean recirculation rate was
24,2 %.
From our results we can conclude that the auscultation is a simple sure and
easy method for the detection of BFD in grafts, if the investigation is prior
to shunt puncture and access blood flow is higher than 400 ml/min. Additional
cost and time will be saved in comparison to HD01
and/or duplex sonography.
Publication Only
|
[F-PO400] Why Don t Some Arteriovenous
Grafts (AVGs) with Low Access Blood Flow (Qa) Clot?
Brian
M. Murray, Neeraj Singh. Dept Of Medicine,
University at Buffalo, Buffalo, NY
Previous studies have suggested that a low Qa(<600ml/min) is
suggestive of imminent AVG thrombosis, but many AVGs
with Qa <600 can maintain patency for a
relatively prolonged period of time. The reason for this is not clear. We
recently measured Qa and cardiac output (CO) (by
Transonic HD02 meter) on 3 occasions, 1 month apart, in 43 patients with
functioning AVGs, who were then followed for a
further 6 months (without further measurements). Ten of the 43 patients had a
value <600ml/min on at least one occasion. Four of these ten AVGs subsequently thrombosed
during the follow-up period, whereas the remaining four remained patent. We
compared a number of clinical parameters between those AVGs
that clotted and those remaining patent (see table 1). The only differences
that reached statistical significance were the ratio of Qa
to CO and the delta Qa (defined as the % change in Qa between the initial and final measurement).
|
Table 1
|
|
|
Thrombosed AVGs (n=4)
|
Patent AVGs(n=6)
|
|
Patient Age (yrs)
|
536
|
6913
|
|
Age of AVG (mo)
|
3339
|
124
|
|
IAP
|
0.630.29
|
0.740.21
|
|
DVP mmHg
|
11821
|
11014
|
|
CO L/min
|
5.40.9
|
4.61.0
|
|
First Qa
|
687113
|
533123
|
|
Qa/CO
|
0.080.02
|
| | | | | | |
