Leiner, Tim

Planken, Nils R.

Tordoir, Jan H.M.

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Regarding “Improvement in the visualization of superficial arm veins being evaluated for access and bypass” 

The fluid and sodium load administered each day following
aortic aneurysm repair is likely to have an important influence on
cardiorespiratory complications as well as on the return of bowel
function. Given the lack of data regarding fluid management,
Goueffic et al’s conclusion that early nasogastric tube removal
reduces complications must be treated with considerable caution.
Further data are needed before any conclusions are drawn with
respect to the place of the nasogastric tube in aortic surgery.
Stewart R Walsh, MB BCh, MRCSEd
Tjun Tang, MB BChir
Michael E. Gaunt, MD, FRCS
Cambridge Vascular Research Unit
Addenbrooke’s Hospital
Cambridge, United Kingdom
REFERENCES
1. Brandstrup B, Tonnesen H, Beier-Holgersen R, Hjortso E, Ording H,
Lindorff-Larsen K, et al. Effects of intravenous fluid restriction on
postoperative complications: comparison of two perioperative fluid reg-
imens: a randomized assessor-blinded multicenter trial. Ann Surg 2003;
238:641-8.
2. Lobo DN, Bostock KA, Neal KR, Perkins AC, Rowlands BJ, Allison SP.
Effect of salt and water balance on recovery of gastrointestinal function
after elective colonic resection: a randomised controlled trial. Lancet
2002;359:1812-8.
doi:10.1016/j.jvs.2005.11.052
Reply
We have read with interest the commentaries from Drs Walsh
and Tang. Although recent studies are consistent with our find-
ings, we agree that the lack of statistical power is an important
drawback of this study. Definitely, a well-designed, multicenter
and adequately powered clinical study should be performed.
Drs Walsh and Tang noticed that the present study does not
report data regarding fluid management, which is known to influ-
ence postoperative complications. However, this monocentric
study is a randomized trial and consequently ensures balance
between patient groups in postoperative fluid management. Of
course, the design of a future large study should take account of the
fluid management during the postoperative period to avoid this
drawback.
Yann Gouëffic, MD
Department of Vascular Surgery
University Hospital of Nantes
Nantes, France
Bertrand Rozec, MD
Department of Anesthesiology
University Hospital of Nantes
Nantes, France
doi:10.1016/j.jvs.2005.12.005
Regarding “Improvement in the visualization
of superficial arm veins being evaluated for access
and bypass”
In their recent report, van Bemmelen et al (J Vasc Surg
2005;42:957-62) address the lack of standardized evaluation of
upper-extremity superficial veins before dialysis access arterio-
venous fistula (AVF) creation. The authors compared six different
methods to determine maximum venous diameter and conclude
that forearm superficial veins distendmaximally in a sitting position
without the use of a tourniquet with the arm dangling down after
the use of warm water immersion.
Although we agree with the authors on the importance of
standardizing the preoperative vein mapping protocol, we believe
that the study has several limitations that were not addressed in the
article:
First, no data are given on the reproducibility of the six
methods. A paper in press from our group reports on the repro-
ducibility of superficial venous diameter measurement by compar-
ing an inflatable cuff with a manually adjusted tourniquet. We
found superficial forearm venous diameter to vary as much as 28%
when using identical assessment protocols on different days.1 In
the absence of reproducibility data on each of the six congestion
methods, it is difficult to assess the influence of each method on
measured venous diameter.
Second, we believe that differences in arm length and distri-
bution of venous valves may be important confounding factors
when venous diameters are measured in the sitting position.2 This
is corroborated by the fact that subject position was found to have
a significant effect on superficial venous diameter (Figs 3 to 5).
Third, we wonder whether “maximum” venous diameter is a
clinically relevant end point. This is because the intravascular
pressure needed to achieve “maximum” venous distension is not
necessarily representative of postoperative intravenous pressure.3
Fourth, the authors do not share our concerns about the
ellipsoid shape of the superficial venous cross-sectional area (CSA)
after maximum venous distension. After AVF creation, postanas-
tomotic intravenous pressures will decline to pressures that do not
result in a circular CSA.3 This ellipsoid CSA shape will result in a
higher resistance compared with a circular CSA shape with a
comparable absolute cross-sectional area.4 In contrast to van Bem-
melen et al, we therefore think that the CSA shape is indeed an
important characteristic of superficial veins and should therefore
also be included as part of the preoperative vein mapping protocol.
In summary, we agree with van Bemmelen et al on the need for
a standardized protocol for preoperative superficial venous assess-
ment. Ideally, a standardized protocol should enable accurate and
reproducible venous assessment, ultimately facilitating a better
understanding and prediction of AVF maturation and function. In
addition, standardized protocols will enable better comparison
between different studies. Further research is needed to determine
which patient position and venous distension maneuvers enable
the most reproducible superficial venous diameter assessment.
Nils R. Planken, MD
Departments of Vascular Surgery and Radiology
University Hospital Maastricht
Maastricht, The Netherlands
Tim Leiner, MD, PhD
Department of Radiology
University Hospital Maastricht
Maastricht, The Netherlands
Jan H.M. Tordoir, MD, PhD
Department of Vascular Surgery
University Hospital Maastricht
Maastricht, The Netherlands
REFERENCES
1. Planken RN, Keuter XHA, Hoeks APG, Kooman JP, van der Sande FM,
Kessels AG, Leiner T, Tordoir JHM. Diameter measurements of the
forearm cephalic vein prior to vascular access creation in end-stage renal
disease patients: graduated pressure cuff versus tourniquet vessel dilata-
JOURNAL OF VASCULAR SURGERY
Volume 43, Number 3 Letters to the Editor 645
tion. Nephrol Dial Transplant, Advance Access published on December
21, 2005; doi:10.1093/ndt/gfi340.
2. Shima H, Ohno K, Shimizu T, Michi K, Egawa K, Takiguchi R. Ana-
tomical study of the valves of the superficial veins of the forearm.
J Craniomaxillofac Surg 1992;20:305-9.
3. Strandness DE, Sumner DS. Hemodynamics for surgeons. New York:
Grune & Stratton; 1975.
4. Kresch E, Noordergraaf A. A mathematical model for the pressure-flow
relationship in a segment of vein. IEEETrans Biomed Eng 1969;16:296-
307.
doi:10.1016/j.jvs.2005.12.015
Reply
We read the above letter with interest, and we recognize the
many contributions made by Tordoir et al to improve the planning
of arteriovenous access procedures.
First, regarding the lack of data on reproducibility of the
“congestion methods,” the method-reproducibility of inflating a
standard-size cuff to a standardized pressure is likely to be high
compared with that of a manually adjusted tourniquet. The varia-
tion they found in measured vein diameters on different days is not
necessarily a reflection of variability of the congestion method, but
is more likely the result of fluctuations in baseline venous-wall
muscle tone. This is affected by such things as temperature, activ-
ity, time of day, hydration, and mental stress, among others.
Second, regarding the influence of arm length and valve
distribution, we did not gather data on either so we cannot
comment on this. We look forward to seeing the author’s data
on this.
Third, regarding the clinical relevance of “maximum” venous
diameter, the method we recommend (measurement sitting, after
immersion in warm water) does not require any tourniquet appli-
cation at all and, therefore, the intravenous pressure will be in the
physiologic venous range. Aside from intraluminal pressure, an
important mechanism for dilation of the vein, both after arterial-
ization and after warm water immersion, is the increase in flow-
related shear stress at the endothelial surface, resulting in nitric
oxide release and vein-wall smooth muscle relaxation.
Fourth, regarding the elliptical cross section of superficial
veins, we agree that superficial arm veins often do not have a
circular cross-sectional area. A comprehensive description would
indeed require reporting of both the longest and shortest axis of
the ellipse. This would be better than using the largest axis only, as
has been practiced in the past. We submit that averaging of the
longest and shortest axis results in a single number, which can be
practical, because the difference between the two after dilation is
not more than 15%.
Finally, we re-emphasize that although size matters for arm
veins, it forms only a small piece of the puzzle with regard to
predicting arteriovenous fistula function compared with other vein
characteristics such as wall fibrosis, calcification, superficial phlebi-
tis, and central stenosis.
Paul S. van Bemmelen, MD, PhD
Patrick Kelly, RVT
John Blebea, MD, FACS
Department of Surgery
Temple University
Philadelphia, Penn
doi:10.1016/j.jvs.2005.12.013
JOURNAL OF VASCULAR SURGERY
March 2006646 Letters to the Editor


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Regarding “Improvement in the visualization of superficial arm veins being evaluated for access and bypass”

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