ORI GI N AL ARTI CLE
Variabilit y of venous hem odynam ics det ect ed by air plet hysm ography in
CEAP clinical classes
Ricardo de Ávila OliveiraI; N ew t on de Barros Jr.I I; Faust o M iranda Jr.I I I
IMSc. in Vascular Surgery, Universidade Federal de S€o Paulo – Escola Paulista de Medicina
(UNIFESP-EPM), S€o Paulo, SP, Brazil.
IIPhysician. Associate professor and head, Vascular Surgery, Department of Surgery,
UNIFESP-EPM, S€o Paulo, SP, Brazil.
IIIProfessor, Vascular Surgery, Department of Surgery, UNIFESP-EPM, S€o Paulo, SP, Brazil.
Correspondence
J Vasc Bras. 2007;6(4):359-65.
RESUM O
Cont ext o: A variabilidade hemodin‚mica da pletismografia a ar ƒ conhecida, mas o exato papel dessa variabilidade no cotidiano cl„nico n€o foi investigado, podendo ter algum significado cl„nico ainda n€o explorado. Sabe-se que h… sobreposi†€o entre as classes cl„nicas (C0 a C6) da
classifica†€o CEAP e mesmo entre membros inferiores de uma mesma classe cl„nica.
Obj et ivo: Avaliar a variabilidade hemodin‚mica dos par‚metros da pletismografia a ar nas classes cl„nicas da classifica†€o CEAP.
M ét odo: Este estudo retrospectivo confronta a doen†a varicosa de membros inferiores classificada de C0 a C6 pela classifica†€o CEAP com os par‚metros hemodin‚micos venosos obtidos pela pletismografia a ar. Os dados obtidos foram tabulados e analisados em suas classes cl„nicas pelos testes de vari‚ncia de Kruskal-Wallys e Barllett.
Result ados:Foram realizados 310 exames em 230 pacientes cujas idades variaram entre 19 a 81 anos, com uma mƒdia de 46,2 anos. Os par‚metros „ndice de enchimento venoso e volume venoso funcional mostraram aumento da variabilidade hemodin‚mica quando analisados na classe cl„nica C0 do CEAP, demonstrada por meio do coeficiente de variabilidade que, para o „ndice de
enchimento venoso foi de 28,12% na classe cl„nica C0 e se manteve acima de 57% nas classes de C2 a C6. A fra†€o de eje†€o e a fra†€o de volume residual n€o aumentaram a variabilidade quando comparados com a classe cl„nica C0 do CEAP.
Conclusão: O „ndice de enchimento venoso foi o melhor par‚metro para avalia†€o e triagem de pacientes com insufici‡ncia venosa crˆnica, mas tem grande variabilidade nas classes cl„nicas C2 a C6 do CEAP.
ABSTRACT
Back ground: The hem odynam ic variabilit y of air plet hysm ogr aphy is know n in t he lit erat ure, but t he clinical significance of t his event has not been invest igat ed yet , and t her e m ay be som e unexplored clinical m eaning. Ther e is know n superposit ioning of CEAP clinical classes ( C0- C6) and even in low er lim bs of t he sam e clinical classes.
Obj ect ive: To evaluat e hem odynam ic var iabilit y of air plet hysm ogr aphy param et ers in CEAP clinical classes.
M et hods: This r et r ospect ive st udy com pares low er lim b var icose disease bet w een C0 and C6 CEAP clinical classes w it h venous hem odynam ic par am et er s obt ained by air plet hysm ogr aphy. Dat a w er e t abled and analyzed according t o t heir clinical classes by Kr uskal- Wallys and Barllet var iance t est s.
Result s: A t ot al of 310 exam inat ions w er e perform ed in 230 pat ient s, aged bet w een 19- 81 year s ( m ean = 46.2 year s) . Venous filling index and funct ional venous volum e increased hem odynam ic variabilit y w hen com par ed w it h CEAP C0. This w as dem onst r at ed by t he var iabilit y coefficient , w hich w as 28.12% for venous filling index in C0 and higher t han 57% bet w een clinical classes C2 and C6. Ej ect ion fr act ion and residual venous fract ion had no incr ease in var iabilit y w hen com par ed w it h CEAP C0.
Conclusion: Venous filling index is t he best par am et er for assessm ent and scr eening pat ient s w it h chronic venous insufficiency, but has gr eat var iabilit y in C2 t o C6 CEAP clinical classes.
Keyw ords:Varicose veins, venous insufficiency, plet hysm ogr aphy.
I nt roduct ion
I n t he st udy of venous diseases, phlebogr aphy is consider ed as t he gold st andar d,1 since it can
provide high- qualit y anat om ic im ages for m ost venous diseases. That exam inat ion, how ever , is invasive and can cause har m t o t he pat ient , w hich lim it s it s use and leads r esear cher s t o st udy noninvasive m et hods.
Color - flow Doppler ult rasound has gained at t ent ion because it is r epr oducible and provides anat om ic and hem odynam ic dat a. For t hose reasons, it st art ed being consider ed as t he m ain
exam inat ion for a proper venous assessm ent ,1 since ev en in C1 and C2 pat ient s, it can br ing
essent ial infor m at ion t o charact erize t he disease and it s t reat m ent .2 Thus, it has also been used in
populat ion st udies.3 How ever , it has lim it at ions, such as low sensit ivit y t o det ect insufficient
per for at ing veins,4 , 5 and it is not able t o pr ovide an over all evaluat ion of venous hem odynam ics,
since it evaluat es independent venous segm ent s. For t hat r eason, it is not able t o dist inguish overall low er lim b hem odynam ic changes dur ing physical act ivit y; som e aut hor s ev en suggest t he
need of associat ing a physiological t est t o m easur e sever it y of venous insufficiency.6
I nt roduct ion and developm ent of air plet hysm ogr aphy in t he diagnosis and pr ognosis of venous
diseases by Christ opoulos et al. in 19877 allow ed venous hem odynam ic evaluat ion under varied
sit uat ions, reinforcing t his m et hod t o be used in clinical pract ice.8 Rout ine use of air
plet hysm ogr aphy as a t ool t o assess venous funct ion has not been pr oper ly st udied by w ell
cont r olled clinical t rials. Ther e are st udies indicat ing t hat r at es of air plet hysm ogr aphy m ay not be
correlat ed w it h t ype of gr eat saphenous vein reflux,9 w hereas ot her s show a cor r elat ion w it h t he
reproducible examination and that the parameter venous filling index (VFI) is a good predictor of venous reflux. However, it is not considered a proper parameter for the prognosis of disease severity or phlebopathic ulcer because it has high rates even in lower clinical classes, in which there are no ulcers.11
The present research study aimed at investigating hemodynamic variability that occurs in venous disease and better define the best criteria for its interpretation, using the parameters of air plethysmography as a study method.
Met hod
Air plethysmography was used in 230 patients, resulting in 310 lower limbs studied. The
examinations were performed at the laboratory of vascular flow at Universidade Federal de S€o Paulo – Escola Paulista de Medicina (UNIFESP-EPM), between February 2002 to November 2003, following the method described by Christopoulos et al.7 The patients were initially assessed
clinically (anamnesis, general physical examination and specific vascular examination). We used the CEAP classification12 to classify lower limbs in:
C0 -no visible or palpable venous disease;
C1 -telangiectasias or reticular veins;
C2 -varicose veins by a diameter of 3 mm or more;
C3 -belonging to C1 and C2 classes with edema;
C4 -hyperpigmentation, eczema, lipodermatosclerosis or white atrophy;
C5 -healed leg ulcers;
C6 -active (open) leg ulcers.
Inclusion criteria were outpatients, patients with lower limb varicose veins, who agreed to
participate in the study, aged between 19-81 years. Thirteen of these patients had one lower limb without venous disease and were selected in clinical class C0. Exclusion criteria were patients with arterial and/or lymphatic diseases, pregnant women, psychiatric patients and those who could not collaborate to perform the examination. The research project was approved by the Research Ethics Committee at UNIFESP-EPM according to resolution 196 from 10.10.96 on research involving human beings. Statistical analysis was performed using the Kruskal-Wallys & Barllett variance tests.13 P ≤ 0.05 was considered significant (95% confidence interval).
Air ple t h y sm ogr a ph y
Air plethysmography was performed according to the protocol proposed by Christopoulos et al.7
reach 90% of t ot al filling is defined as venous filling t im e 90 ( VFT 90) . The relat ion bet w een variat ion in produced volum e, divided by it s cor r esponding t im e in seconds w hen changing fr om t he lying t o t he supine posit ion w as t hen m easur ed, obt aining VFI . That index is obt ained by t he
form ula VFI = 90% VV/ VFT 90, and t he values are expr essed in m L/ s.1 4 Next , t he pat ient w as
request ed t o st and on bot h feet and per for m a single m ovem ent of plant ar flexion, causing cont ract ure in t he calf m uscle and, soon aft er , t he pat ient should ret urn t o init ial posit ion.
Deflexion in t he obt ained cur ve cor r esponded t o ej ect ion volum e ( EV) , result ing from calf m uscle cont r act ion. Aft er t hat m ovem ent , w e w ait ed for a new cur ve st abilizat ion and t he pat ient w as request ed t o per for m 10 plant ar flexion m ovem ent s, one at each second. Decr eased volum e w as also recorded. Residual volum e ( RV) is calculat ed based on final basal value in relat ion t o
rem aining v olum e at t he end of m ovem ent s. Ej ect ion fr act ion ( EF) w as t hen calculat ed, based on EF = ( EV/ VV) x 100, and residual volum e fract ion ( RVF) based on RVF = ( RV/ VV) x 100. When t he t est w as over, t he pat ient r et ur ned t o st anding rest posit ion and, once t he cur ve w as st abilized, he ret urned t o t he supine posit ion.7 , 8
Result s
CEAP cla ssifica t ion
All 310 low er lim bs w er e classified accor ding t o CEAP classificat ion:
C0: 13 ( 4.2% )
C2: 108 ( 34.8% )
C3: 44 ( 14.2% )
C4: 35 ( 11.3% )
C5: 19 ( 6.2% )
C6: 76 ( 24.5% )
Venous filling index. Figure 2 show s a cur ve w it h a gr ow t h t endency in VFI v alues in higher classes of t he CEAP clinical classificat ion. I n int r aclass analyses, VFI v alues w er e st at ist ically different ( Kruskal- Wallys t est , p < 0.0000) . I nt raclass analysis also show ed a t endency of higher dat a var iat ion ( box sizes) pr opor t ional t o venous disease sever it y, consider ing t hat var iances bet w een CEAP clinical classes are st at ist ically differ ent bet w een t hem selves, confir m ed by Bar t let t t est for var iance hom ogeneit y ( p < 0.0000) .
Venous volum e. Figure 3 show s t he gr ow t h t endency of VV values pr opor t ional t o clinical
Ej ect ion fract ion. Figure 4 show s t he t endency of m edian EF values t o r em ain const ant w it h CEAP classificat ion. Such t endency w as confir m ed by t he non- significant result of t he Kr uskal- Wallis t est , w hich does not indicat e any difference bet w een EF values in CEAP clinical classes ( p = 0.4177) .
Residual volum e fract ion. Figure 4 show s t hat t here w er e no var iat ions in m edian values and in RVF variabilit y as t o CEAP clinical classificat ion. Differences in RVF var iances as t o CEAP
classificat ion w er e not significant according t o Bar t let t t est ( p = 0.3595) , and t he sam e occur r ed t o t he param et er values of RVF dist r ibut ion locat ion, w hose differences w er e not st at ist ically
significant by t he Kr uskal- Wallis t est ( p = 0.519) .
Figure 4 show s t he com par ison of air plet hysm ogr aphy param et er dat a ( VFI , VV, EF and RVF) and t he evolut ion of hem odynam ic variabilit y bet w een CEAP clinical classes.
100. Thus, an obj ect ive m easur em ent of dat a variabilit y can be obt ained in each CEAP clinical class and for each par am et er analyzed.
Figure 5 show s VC values for VFI , VV, EF and RVF m easur em ent s according t o CEAP classificat ion. VFI and VV had a quit e sim ilar VC in nor m al individuals ( C0) ; how ever , as t he disease becam e m ore severe ( CEAP classificat ion w or sened) , VFI VC increased up t o 70% for CEAP C2. Such increase r epr esent s m or e t han 200% in relat ion t o CEAP clinical class C0. ( For var iables VV and EF t here w as also a sm all variat ion in VC as t he CEAP classificat ion incr eased, w hich w as a discret e increase w hen com par ed w it h VFI . RVF VC rem ained t he sam e bet w een C0 and C3, falling a lit t le in C4 and rising again for C5 and C6, but not being higher t han t he v alues for C0) .
Discussion
Despit e CEAP classificat ion being t he m ost w idely used for clinical classificat ion of chronic venous insufficiency, it is st ill subj ect t o cr it icism s because it does not answ er all doubt s by clinicians or sur geons.1 5 I t can have large int errat er var iabilit y, r equir ing par am et er s t hat bet t er st andar dize such sit uat ion, cr eat ing space for assessm ent t hr ough ot her com plem ent ar y exam inat ions.
Use of color- flow Doppler ult rasound has lim it at ions of hem odynam ic evaluat ion pert inent t o t hat
m et hod.1 6 Aft er int r oduct ion of air plet hysm ogr aphy, VFI pr oved t o be t he plet hysm ogr aphic
param et er t hat best expr esses clinical sever it y of chr onic venous insufficiency.1 1 , 1 7 , 1 8 Thus, t his st udy is im port ant t o t est possibilit ies of pr act ical use of air plet hysm ogr aphy.
How ever, w e can see in t he pr esent st udy a large var iabilit y of plet hysm ogr aphic par am et er s, especially VFI , in all CEAP clinical classes w hen com par ed w it h CEAP clinical class C0 ( Figur es 2 and 5) . VC, w hich w as 28.12% in clinical class C0, w ent t o 70% in clinical class C2, w hich had t he highest VC, pr obably because it had t he largest sam ple. This can m ake t he associat ion bet w een VFI and disease sever it y difficult , since in t his st udy w e verified low er lim bs of clinical class C2 w it h VFI sim ilar t o low er lim bs of clinical class C6, and t he opposit e w as also t r ue.
There are still doubts as to factors and consequences of VFI variability in chronic venous
insufficiency. There may be compensatory mechanisms to avoid formation of leg ulcers in lower limbs with varicose veins.17,19 Such mechanisms can range from proper lymphatic drainage to
efficient fibrinolytic activity, removing excess of extravascular fluid and fibrin deposits.20Another
hypothesis is that the condition of high VFI is not present for a sufficient amount of time to cause skin lesions of chronic venous insufficiency.21 But the causes of that large hemodynamic variability
can be attributed to the examiner, patient, environment in which the examination is performed and to variability of venous disease.22 Therefore, we believe proper examiner training, adequate patient
collaboration, patient's age and control of room temperature are essential to standardize air plethysmography. Of those factors, patient collaboration is very important to determine EF and VFR, since these are dependent on muscle strength (plantar flexion). Thus, VFI and VV parameters are the most reliable in air plethysmography, since they depend less on patient collaboration.
Considering that VFI is an adequate plethysmographic parameter to classify severity of venous disease,21we have seen in this study that there is a considerable number of lower limbs that
probably have higher risk than others of developing chronic venous insufficiency and ulcers. That index may suggest which patient, within the same clinical class, should be prioritized for surgical treatment of lower limb varicose veins before there are any complications.
When a given clinical class is studied, it can be observed that the mean obtained from
plethysmographic values is little influenced by extreme values, and these are not good parameters for evaluation of variability.23 Our study detected the following VFI extreme values: zero
individuals in C0, one individual in C1, two in C2, three in C3, two in C4, zero in C5 and three in C6 (Figure 2). This justifies use of VC to make variability data of air plethysmography more
understandable.
VC was not able to distinguish CEAP clinical classes C2 to C6 as independent groups, but VFI was the parameter with the highest variation, which makes it more reliable in the plethysmographic assessment of venous insufficiency.
It is worth remembering that air plethysmography can also provide data as to use of compressive measurements in the treatment of varicose disease7,24,25 and even provide subsides for the
prognosis of lower limb varicose vein surgery.26,27
Conclusions
Based on obtained data, we can conclude that VFI was the best plethysmographic parameter to assess patients with chronic venous insufficiency and has large hemodynamic variability in several CEAP clinical classes. Therefore, it can be said that, using air plethysmography, there are patients with more or less severity in the same CEAP clinical class, and these parameters can be used to prioritize lower limbs for surgery to repair chronic venous insufficiency of the lower limbs. This may imply that VFI is the prognostic factor for evolution of chronic venous insufficiency.
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Correspondence:
Ricardo de •vila Oliveira
Rua Artur Bernardes, 426, Bairro Martins CEP 38400-368 – Uberl‚ndia, MG, Brazil Tel.: (34) 3235.9874
Fax: (34) 3235.9874
Email: avila@circulare.com.br
This study is part of the master's thesis presented at Universidade Federal de S€o Paulo to obtain the title of Master in Vascular Surgery in the Graduate Program in Vascular, Cardiac, Thoracic Surgery and Anesthesiology, UNIFESP-EPM, S€o Paulo, SP, Brazil.
