Review Article
Compression in mixed ulcers: venous side
Phlebology 2014, Vol. 29(1S) 13–17 ! The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0268355514526676 phl.sagepub.com
Giovanni Mosti
Abstract Introduction: arterial involvement may coexist in about 15–30 of venous ulcers. In this case compression therapy maybe applied, only by expert caregivers, with a reduced pressure which must not overcome the arterial pressure at ankle and foot level. It remains to assess if such a reduced pressure may be effective also on the impaired venous hemodynamics. Aim of this paper is to present an overview of the data we have, showing the effects on venous hemodynamics of a reduced compression pressure. Material and methods: in different groups of patients affected by deep and superficial venous incompetence, venous reflux and ejection fraction (EF) from the lower leg were measured in baseline conditions, without any compression, and after application of different elastic and inelastic compression devices exerting different pressure ranges from 20 to 60 mm Hg. The compression pressure was always recorded simultaneously with venous reflux of EF assessment. Results: strong pressures show the greatest effect in reducing/abolishing venous reflux and increasing EF but also a reduced pressure in the range of 20 to 40 mm Hg is effective in improving venous hemodynamics provided inelastic materials are used. Conclusions: inelastic but not elastic materials exert a standing pressure which is significantly higher than in supine position even starting from a reduced supine pressure of 40 mm Hg which does not impair the arterial inflow. This strong pressure is able to reduce and even abolish the venous reflux and improve the EF up to restoring its normal range. A reduced or modified compression pressure is able to significantly improve the venous hemodynamics without affecting the arterial inflow in patients with mixed ulcers, provided inelastic materials are used.
Keywords mixed ulcers, venous hemodynamics, venous reflux, ejection fraction, inelastic compression, elastic compression
Introduction In about 15–30% of patients with venous leg ulcers (VLU) an arterial disease coexists.1,2 In these patients, compression is a critical issue as it is able to improve the impaired venous haemodynamics but it could potentially hindrance the arterial perfusion. As a consequence in clinical studies on VLU, an Ankle Brachial Pressure Index (ABPI) lower than 0.8 is usually considered an exclusion criterion for compression therapy.3 Nevertheless the ‘‘venous component’’ of mixed ulcers needs compression and a ‘‘reduced’’ or ‘‘modified’’ compression, with reduced pressure, applied by expert doctors or nurses, is recommended in patients with arterial impairment and an ABPI of 0.5–0.8.4–8 However what reduced or modified compression means was never defined. In a previous study,9 in a cohort of patients affected by mixed ulcers, we tried to define a compression pressure range which could improve the venous haemodynamics and, simultaneously, not impair the arterial
flow. In this paper we realized that, compared with ABPI, the perfusion pressure is a much better indicator to define a correct compression pressure range. In that paper we reported that ‘‘Although ABPI is generally used in daily practice to assess the severity of arterial occlusive disease, the absolute values of the ankle pressure give a very clear warning signal when a bandage is applied since it is evident that any sustained external compression pressure should never exceed this perfusion pressure.’’ Using a Laser Doppler flowmeter, we measured the arterial flow in the peri-wound area under compression and distally to an inelastic bandage applied from the
Angiology Department, Clinica MD Barbantini, Lucca - Italy Corresponding author: Giovanni Mosti, Angiology Department, Clinica MD Barbantini, Via del Calcio No.2, 55100, Lucca, Italy. Email: [email protected]
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base of the toes to the knee with different supine pressure ranges from 20 to 50 mm Hg. In addition we measured the effects of the compression on the toe pressure and on TcPO2 assessed on the foot dorsum distally to the bandage. We could observe that a compression pressure up to 40 mm Hg seems not to impair but rather to improve the arterial inflow provided the arterial systolic pressure at ankle level is higher than 60 mm Hg. This compression pressure increased arterial flow in the periwound skin by 25% (p < 0.05) and the TcPO2 on the foot dorsum by a small (7%) but significant amount (p < 0.001), without impairing the toe pressure. It remains to check if such a pressure may be effective also on the venous side of mixed ulcers or if it is not high enough to improve the venous hemodynamic which is impaired in patients with superficial or deep venous insufficiency. Venous incompetence is characterized by varying and complex haemodynamic mechanisms. However, venous reflux and a reduced ejection fraction (EF) from the lower leg during exercise are key constant pathophysiological parameters. 10 The following will give an overview of results reported in different papers on effects of a reduced compression pressure on venous reflux and reduced EF in patients with venous disease which represents the other side of the mixed ulcers pathophysiology.
Material and methods Venous reflux 33 patients were enrolled in two different studies.11,12 In 21 affected by deep venous incompetence, venous reflux was measured by air plethysmography calculating Venous Filling Index (VFI);11 in 12 patients affected by great saphenous vein incompetence, venous reflux was assessed by means of Duplex scanner measuring the mean velocity at peak reflux.12 Both VFI in the first study and mean velocity at peak reflux in the second study were measured in baseline conditions and after application of an elastic and inelastic material with a pressure at application in supine position of 20, 40 and 60 mm Hg.
stockings, elastic and inelastic bandages. Four studies, involving 93 patients, were selected in this overview9,14–16 as EF was calculated after application of a reduced pressure of about 40 mm Hg defined as beneficial in patients with arterial involvement.
Pressure measurement In all reported studies the pressure exerted by compression devices, defined interface pressure (IP) was measured simultaneously with measurement of venous reflux or ejection fraction by means of validated devices using pneumatic system;17,18 the stiffness of different materials was calculated by means of Static Stiffness Index19 which is the difference between standing and supine pressure and Walking Pressure Amplitudes (WPA)14 which is the difference between systolic and diastolic pressure during exercise.
Statistical Analysis Data in different studies were submitted to statistical analysis. For comparisons between the different treatment groups, the non-parametric Mann-Whitney rank sum test and Kruskal-Wallis statistics with Dunn’s multiple comparisons were used. The Wilcoxon test was used for the comparison of pairs and the Spearman rank test was taken as a nonparametric method for quantifying correlations. Differences with a P < 0.05 were considered statistically significant. The graphs and the statistical evaluations were generated using Graph Pad Prism software (Graph Pad, San Diego, CA, USA).
Results Venous reflux Both studies11,12 reported that compression effectiveness in reducing venous reflux is directly related to compression pressure: the higher the pressure the greater the reflux reduction. An IP of 20 mm Hg with inelastic material are able to reduce reflux by about 60%; an IP of 40 mm Hg by 80% and an IP of 60 mm Hg is able to completely abolish venous reflux (Figures 1–2).
Ejection fraction
Ejection fraction
Calculated according to the protocol described by Poelkens,13 ejection fraction was assessed by means of strain gauge plethysmography in patients affected by great saphenous vein incompetence. With the strain gauge probe placed proximally to the compression device EF was measured in baseline conditions, without any compression, and after application of elastic
EF was measured in 14 patients with mixed ulcers9 after applying inelastic compression in the low ranges of 20– 30 and 30–40 mm Hg. A significant increase (72%) of EF was observed already with a pressure of 20 to 30 mm Hg. The ejection fraction was restored into its normal range (being increased by 102%) with a pressure of 30 to 40 mm Hg (Figures 3–4). These results
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interface pressure with inelastic material 100
80
mm Hg
60
40
20
0 Minimum 25% Percentile Median 75% Percentile Maximum
supine 19.00 19.25 21.00 22.00 22.00
standing 36.00 36.25 38.50 43.75 49.00
supine 37.00 39.50 41.00 42.00 43.00
standing 54.00 57.25 60.00 63.25 66.00
supine 57.00 58.25 60.00 62.50 63.00
standing 79.00 82.00 86.00 88.50 89.00
Figure 1. supine and standing pressure exerted by inelastic bandages applied with different supine pressure. Standing- is much higher than supine pressure.
resulted directly related to standing pressure and to material stiffness assessed by the Static Stiffness Index and by the systolic-diastolic pressure difference during walking (WPA: massaging effect).14 There is a direct correlation between EF and compression pressure at bandage application: the higher the pressure the higher the EF provided inelastic material is used.15 An IP of 20 mm Hg increased the EF by 62%, an IP of 40 mm Hg increased the EF by 83% and an IP of 60 mm Hg increased the EF by 93%.15 EF is restored into its normal range by applying an inelastic bandage exerting 40 and 60 mm Hg. In another paper we measured interface pressure and ejection fraction after one week since bandage application in order to check if inelastic compression maintains its effectiveness overtime.16 After one week the compression pressure decreased from about 60 mm Hg (application) to about 30 mm Hg. Despite of this significant pressure loss, ejection fraction remained in the normal range although it was reduced compared to the ‘‘application’’ measurement (64,5% versus 77.9%).
Discussion reflux volume 80
ml//sec
60 40 20 0 Minimum 25% Percentile Median 75% Percentile Maximum
baseline 24.70 29.28 44 44. 05 53.08 58.60
21 mm Hg 11.80 19.80 21. 20 21 28.93 42.10
41 mm Hg 0.0 4.950 8. 800 8 13.38 18.60
60 mm Hg 0.0 0.0 0.0 0 0.0 0.0
Figure 2. venous reflux measured in baseline conditions, without any compression, and after application of inelastic compression exerting different supine pressure.
from a small group of patients confirm data reported in previous papers where compression was applied with low and moderate pressure. Applying the bandages with a reduced pressure of 40 mm Hg we observed that inelastic- is significantly more effective than elastic compression in increasing EF.14 Compared to baseline assessment, without any compression, EF improved by 33% with elastic material and by 90% with inelastic material. Only with inelastic material EF was restored into its normal range, which is higher than 60%.14 EF improvement
In mixed ulcers compression therapy cannot be applied with the same strong pressure usually exerted in venous ulcers. Compression pressure must always be lower than the perfusion pressure in order not to impede the arterial inflow. In a paper on compression in mixed ulcers9 we could observe that an inelastic bandage exerting a reduced pressure up to 40 mm Hg does not hindrance but seems rather increase the arterial inflow. It could be questionable if such a reduced pressure can be effective in improving the impaired venous hemodynamics which represents the other side of the mixed ulcer pathophysiology. In the same group of patients with mixed ulcers we selected a sub-group of 14 patients who were able to perform the exercise necessary to measure the ejection fraction and applied an inelastic bandage with a pressure range of 20–30 mm Hg and of 30–40 mm Hg. Even with this reduced pressure inelastic compression increased significantly the EF. With an interface pressure of 20 to 30 mm Hg EF increased to more than 50% and with an interface pressure of 30 to 40 mm Hg EF was restored into its normal range greater than 60%. These data confirm old data coming from different papers:14–16 although strong interface pressure, higher than 60 mm Hg, produces the maximal increase of EF,15,16 every time inelastic compression was applied, even a reduced pressure of 20, 30 or 40 mm Hg was able to increase significantly the EF and restore it into its normal range when the pressure is higher than 30 mm Hg.
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supine pressure
(A)
standing pressure
(B)
80
80
70 60
50
mm Hg
mm Hg
60 40 30 20
40 20
10 0 Minimum 25% Percentile Median 75% Percentile Maximum
ref. 15 16.00 20.00 20.50 22.00 24.00
ref. 9 22.00 24.00 25.00 26.00 28.00
ref. 16 27.00 28.00 30.50 33.25 41.00
ref. 9 32.00 34.00 35.00 36.00 39.00
ref. 14 35.00 40.00 42.00 43.00 47.00
ref. 15 39.00 40.00 41.00 41.00 43.00
0 Minimum 25% Percentile Median 75% Percentile Maximum
ref. 15 20.00 33.00 36.00 40.75 51.00
ref. 9 26.00 38.00 40.00 43.00 50.00
ref. 16 34.00 44.00 49.00 53.00 59.00
ref. 9 48.00 50.00 52.00 54.00 60.00
ref. 14 59.00 60.00 63.00 68.00 71.00
ref. 15 55.00 58.00 61.00 64.75 67.00
Figure 3. (3A) Supine interface pressure in the mild and moderate range (up to 40 mm Hg); (3B) corresponding standing pressure. X axis: reference papers data are reported from.
Ejection Fraction 100
normal range 80
%
60
40
20
0
Minimum Mi i 25% Percentile Median 75% Percentile Maximum
base line
b.l.EF 15.80 23.80 32.80 37.00 50.10
compression pressure < 30 mm Hg
ref. 15 23.90 49.83 52.00 58.40 70.60
ref. 9 40.20 52.00 54.30 56.00 64.10
compression pressure > 30 mm Hg
ref. 16 47.30 57.93 64.55 73.80 86.50
ref. 9 55.90 58.60 62.60 69.90 78.50
ref. 14 52.30 57.78 62.75 68.88 87.40
ref. 15 31.70 53.45 61.55 68.80 89.40
Figure 4. Ejection Fraction corresponding to pressure ranges as reported in Figure. 3. EF is significantly improved compared to average baseline EF, without any compression, even with a compression pressure lower than 30 mm Hg. EF is restored into its normal range (>60%) when the compression pressure is higher than 30 mm Hg. X axis: reference papers data on EF are reported from. b.l. EF: baseline EF.
Venous reflux was not directly studied in patients with mixed ulcers but only in patients with venous insufficiency even if those results may reasonably be extended to patients with mixed ulcers: strong pressure can achieve the best effectiveness in reducing/abolishing venous reflux but also lower pressure ranges, when
exerted by inelastic material, are able to reduce significantly the venous reflux.11,12 The reported data could seem in contradiction with results from other papers. It is well known that compression therapy is able to improve the venous hemodynamics by reducing up to occluding the venous system. The compression pressure necessary to influence the venous diameter depends on the body position. In supine position a low pressure of 20 mm Hg is enough to occlude the venous lumen. The compression pressure necessary to interfere with the venous diameter rises to about 50 mm Hg in sitting position and must exceed 60 mm Hg when the patients stands up and walks.20,21 These data could support the hypothesis that a supine pressure of 40 mm Hg is not enough to improve the venous hemodynamics when the patient stands up. But it must be taken into account that, when exerted by inelastic material, the pressure rises significantly from the supine to the standing position and during exercise. With this material a supine pressure of 40 mm Hg may easily rise to more than 60 mm Hg in standing position being able to interfere with the venous diameter by approaching or overcoming the intravenous pressure so improving the venous hemodynamics. An intermittent occlusion of the incompetent veins at every step is able to restore a kind of artificial valve mechanism22 making possible the reduction/abolition of venous reflux and the improvement on EF. Elastic material exerts a standing pressure which is only slightly higher than the supine pressure; its SSI and WPA are very low as their ‘‘massaging effect’’.
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These characteristics make elastic material significantly less effective in reducing venous reflux and increasing EF11,12,14–16 and not effective enough with a reduced pressure.
Conclusion In patients with mixed ulcers a ‘‘reduced’’ or ‘‘modified’’ compression pressure of 40 mm Hg in supine position, when exerted by an inelastic bandage, is able to significantly improve the impaired venous hemodynamics without impeding the arterial inflow. Conflict of interest The authors has no conflict of interest and nothing to disclose.
Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
References 1. Humphreys ML, Stewart AH, Gohel MS, Taylor M, Whyman MR and Poskitt KR. Management of mixed arterial and venous leg ulcers. Br J Surg 2007; 94: 1104–7. 2. Andersson E, Hansson C and Swanbeck G. Leg and foot ulcer prevalence and investigation of the peripheral arterial and venous circulation in a randomised elderly population: an epidemiological survey and clinical investigation. Acta Derm Venereol 1993; 73: 57–61. 3. O’Meara S, Cullum NA and Nelson EA. Compression for venous leg ulcers. Cochrane Database of Systematic Reviews 2009; Issue 1. Art. No.: CD000265. 4. Grey JE, Enoch S and Harding KG. ABC of wound healing: venous and arterial leg ulcers. BMJ 2006; 332: 347–350. 5. Hopf HW, Ueno C, Aslam R, Burnand K, Fife C, Grant L, Holloway A, Iafrati MD, Mani R, Misare B, Rosen N, Shapshak D, Benjamin Slade J Jr, West J and Barbul A. Guidelines for the treatment of arterial insufficiency ulcers. Wound Repair Regen 2006; 14: 693–710. 6. World Union of Wound Healing Societies’ Initiative (WUWHS) Compression in venous leg ulcers. A consensus document. London MEP Ltd 2008. 7. Neglen P, Writing Group II of the Pacific Vascular Symposium 6, Eklo¨f B, Kulwicki A, Davies A, Deschamps T, Garcia M, Gloviczki P, Labropoulos N, Nicolaides A, Partsch H, Perrin M, Rabe E and Wittens C. Prevention and treatment of venous ulcers in primary chronic venous insufficiency. J Vasc Surg 2010; 52(5 Suppl): 15S–20S.
8. Stacey M, Falanga V, Marston W, Moffatt C, Phillips T, Sibbald RG, Vanscheidt W and Lindholm C. The use of compression therapy in the treatment of venous leg ulcers: a recommended management pathway. EWMA Journal 2002; 2: 9–13. 9. Mosti G, Iabichella ML and Partsch H. Compression therapy in mixed ulcers increases venous output and arterial perfusion. JVS 2012; 55: 122–8. 10. Nicolaides A and Christopoulos D. Quantification of venous reflux and outflow obstruction with air-plethysmography. In: Bernstein EF (ed.) Vascular Diagnosis. St Louis: Mosby, 1993, pp.915–921. 11. Partsch H, Menzinger G and Mostbeck A. Inelastic leg compression is more effective to reduce deep venous refluxes than elastic bandages. Dermatol Surg 1999; 2(5): 695–700S. 12. Mosti G and Partsch H. Duplex scanning to evaluate the effect of compression on venous reflux. Int Angiol 2010; 29: 416–20. 13. Poelkens F, Thijssen DH, Kersten B, Scheurwater H, van Laarhoven EW and Hopman MT. Counteracting venous stasis during acute lower leg immobilization. Acta Physiol 2006; 186: 111–8. 14. Mosti G, Mattaliano V and Partsch H. Inelastic compression increases venous ejection fraction more than elastic bandages in patients with superficial venous reflux. Phlebology 2008; 23: 287–94. 15. Mosti G and Partsch H. Is low compression pressure able to improve venous pumping function in patients with venous insufficiency? Phlebology 2010; 25: 145–50. 16. Mosti G and Partsch H. Inelastic bandages maintain their hemodynamic effectiveness over time despite significant pressure loss. J Vasc Surg 2010; 52: 925–31. 17. Partsch H and Mosti G. Comparison of three portable instruments to measure compression pressure. Int Angiol 2010; 29: 426–30. 18. Mosti G and Rossari S. L’importanza della misurazione della pressione sottobendaggio e presentazione di un nuovo strumento di misura. Acta Vulnol 2008; 6: 31–36. 19. Partsch H. The static stiffness index: a simple method to assess the elastic property of compression material in vivo. Dermatol Surg 2005; 31: 625–630. 20. Partsch B and Partsch H. Calf compression pressure required to achieve venous closure from supine to standing position. J Vasc Surg 2005; 42: 734–8. 21. Partsch H, Mosti G and Mosti F. Narrowing of leg veins under compression demonstrated by magnetic resonance imaging (MRI). Int Angiol 2010; 29: 408–10. 22. Partsch B, Mayer W and Partsch H. Improvement of ambulatory venous hypertension by narrowing of the femoral vein in congenital absence of venous valves. Phlebology 1992; 7: 101–104.
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Compression in mixed ulcers: venous side
Phlebology 2014, Vol. 29(1S) 13–17 ! The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0268355514526676 phl.sagepub.com
Giovanni Mosti
Abstract Introduction: arterial involvement may coexist in about 15–30 of venous ulcers. In this case compression therapy maybe applied, only by expert caregivers, with a reduced pressure which must not overcome the arterial pressure at ankle and foot level. It remains to assess if such a reduced pressure may be effective also on the impaired venous hemodynamics. Aim of this paper is to present an overview of the data we have, showing the effects on venous hemodynamics of a reduced compression pressure. Material and methods: in different groups of patients affected by deep and superficial venous incompetence, venous reflux and ejection fraction (EF) from the lower leg were measured in baseline conditions, without any compression, and after application of different elastic and inelastic compression devices exerting different pressure ranges from 20 to 60 mm Hg. The compression pressure was always recorded simultaneously with venous reflux of EF assessment. Results: strong pressures show the greatest effect in reducing/abolishing venous reflux and increasing EF but also a reduced pressure in the range of 20 to 40 mm Hg is effective in improving venous hemodynamics provided inelastic materials are used. Conclusions: inelastic but not elastic materials exert a standing pressure which is significantly higher than in supine position even starting from a reduced supine pressure of 40 mm Hg which does not impair the arterial inflow. This strong pressure is able to reduce and even abolish the venous reflux and improve the EF up to restoring its normal range. A reduced or modified compression pressure is able to significantly improve the venous hemodynamics without affecting the arterial inflow in patients with mixed ulcers, provided inelastic materials are used.
Keywords mixed ulcers, venous hemodynamics, venous reflux, ejection fraction, inelastic compression, elastic compression
Introduction In about 15–30% of patients with venous leg ulcers (VLU) an arterial disease coexists.1,2 In these patients, compression is a critical issue as it is able to improve the impaired venous haemodynamics but it could potentially hindrance the arterial perfusion. As a consequence in clinical studies on VLU, an Ankle Brachial Pressure Index (ABPI) lower than 0.8 is usually considered an exclusion criterion for compression therapy.3 Nevertheless the ‘‘venous component’’ of mixed ulcers needs compression and a ‘‘reduced’’ or ‘‘modified’’ compression, with reduced pressure, applied by expert doctors or nurses, is recommended in patients with arterial impairment and an ABPI of 0.5–0.8.4–8 However what reduced or modified compression means was never defined. In a previous study,9 in a cohort of patients affected by mixed ulcers, we tried to define a compression pressure range which could improve the venous haemodynamics and, simultaneously, not impair the arterial
flow. In this paper we realized that, compared with ABPI, the perfusion pressure is a much better indicator to define a correct compression pressure range. In that paper we reported that ‘‘Although ABPI is generally used in daily practice to assess the severity of arterial occlusive disease, the absolute values of the ankle pressure give a very clear warning signal when a bandage is applied since it is evident that any sustained external compression pressure should never exceed this perfusion pressure.’’ Using a Laser Doppler flowmeter, we measured the arterial flow in the peri-wound area under compression and distally to an inelastic bandage applied from the
Angiology Department, Clinica MD Barbantini, Lucca - Italy Corresponding author: Giovanni Mosti, Angiology Department, Clinica MD Barbantini, Via del Calcio No.2, 55100, Lucca, Italy. Email: [email protected]
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base of the toes to the knee with different supine pressure ranges from 20 to 50 mm Hg. In addition we measured the effects of the compression on the toe pressure and on TcPO2 assessed on the foot dorsum distally to the bandage. We could observe that a compression pressure up to 40 mm Hg seems not to impair but rather to improve the arterial inflow provided the arterial systolic pressure at ankle level is higher than 60 mm Hg. This compression pressure increased arterial flow in the periwound skin by 25% (p < 0.05) and the TcPO2 on the foot dorsum by a small (7%) but significant amount (p < 0.001), without impairing the toe pressure. It remains to check if such a pressure may be effective also on the venous side of mixed ulcers or if it is not high enough to improve the venous hemodynamic which is impaired in patients with superficial or deep venous insufficiency. Venous incompetence is characterized by varying and complex haemodynamic mechanisms. However, venous reflux and a reduced ejection fraction (EF) from the lower leg during exercise are key constant pathophysiological parameters. 10 The following will give an overview of results reported in different papers on effects of a reduced compression pressure on venous reflux and reduced EF in patients with venous disease which represents the other side of the mixed ulcers pathophysiology.
Material and methods Venous reflux 33 patients were enrolled in two different studies.11,12 In 21 affected by deep venous incompetence, venous reflux was measured by air plethysmography calculating Venous Filling Index (VFI);11 in 12 patients affected by great saphenous vein incompetence, venous reflux was assessed by means of Duplex scanner measuring the mean velocity at peak reflux.12 Both VFI in the first study and mean velocity at peak reflux in the second study were measured in baseline conditions and after application of an elastic and inelastic material with a pressure at application in supine position of 20, 40 and 60 mm Hg.
stockings, elastic and inelastic bandages. Four studies, involving 93 patients, were selected in this overview9,14–16 as EF was calculated after application of a reduced pressure of about 40 mm Hg defined as beneficial in patients with arterial involvement.
Pressure measurement In all reported studies the pressure exerted by compression devices, defined interface pressure (IP) was measured simultaneously with measurement of venous reflux or ejection fraction by means of validated devices using pneumatic system;17,18 the stiffness of different materials was calculated by means of Static Stiffness Index19 which is the difference between standing and supine pressure and Walking Pressure Amplitudes (WPA)14 which is the difference between systolic and diastolic pressure during exercise.
Statistical Analysis Data in different studies were submitted to statistical analysis. For comparisons between the different treatment groups, the non-parametric Mann-Whitney rank sum test and Kruskal-Wallis statistics with Dunn’s multiple comparisons were used. The Wilcoxon test was used for the comparison of pairs and the Spearman rank test was taken as a nonparametric method for quantifying correlations. Differences with a P < 0.05 were considered statistically significant. The graphs and the statistical evaluations were generated using Graph Pad Prism software (Graph Pad, San Diego, CA, USA).
Results Venous reflux Both studies11,12 reported that compression effectiveness in reducing venous reflux is directly related to compression pressure: the higher the pressure the greater the reflux reduction. An IP of 20 mm Hg with inelastic material are able to reduce reflux by about 60%; an IP of 40 mm Hg by 80% and an IP of 60 mm Hg is able to completely abolish venous reflux (Figures 1–2).
Ejection fraction
Ejection fraction
Calculated according to the protocol described by Poelkens,13 ejection fraction was assessed by means of strain gauge plethysmography in patients affected by great saphenous vein incompetence. With the strain gauge probe placed proximally to the compression device EF was measured in baseline conditions, without any compression, and after application of elastic
EF was measured in 14 patients with mixed ulcers9 after applying inelastic compression in the low ranges of 20– 30 and 30–40 mm Hg. A significant increase (72%) of EF was observed already with a pressure of 20 to 30 mm Hg. The ejection fraction was restored into its normal range (being increased by 102%) with a pressure of 30 to 40 mm Hg (Figures 3–4). These results
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interface pressure with inelastic material 100
80
mm Hg
60
40
20
0 Minimum 25% Percentile Median 75% Percentile Maximum
supine 19.00 19.25 21.00 22.00 22.00
standing 36.00 36.25 38.50 43.75 49.00
supine 37.00 39.50 41.00 42.00 43.00
standing 54.00 57.25 60.00 63.25 66.00
supine 57.00 58.25 60.00 62.50 63.00
standing 79.00 82.00 86.00 88.50 89.00
Figure 1. supine and standing pressure exerted by inelastic bandages applied with different supine pressure. Standing- is much higher than supine pressure.
resulted directly related to standing pressure and to material stiffness assessed by the Static Stiffness Index and by the systolic-diastolic pressure difference during walking (WPA: massaging effect).14 There is a direct correlation between EF and compression pressure at bandage application: the higher the pressure the higher the EF provided inelastic material is used.15 An IP of 20 mm Hg increased the EF by 62%, an IP of 40 mm Hg increased the EF by 83% and an IP of 60 mm Hg increased the EF by 93%.15 EF is restored into its normal range by applying an inelastic bandage exerting 40 and 60 mm Hg. In another paper we measured interface pressure and ejection fraction after one week since bandage application in order to check if inelastic compression maintains its effectiveness overtime.16 After one week the compression pressure decreased from about 60 mm Hg (application) to about 30 mm Hg. Despite of this significant pressure loss, ejection fraction remained in the normal range although it was reduced compared to the ‘‘application’’ measurement (64,5% versus 77.9%).
Discussion reflux volume 80
ml//sec
60 40 20 0 Minimum 25% Percentile Median 75% Percentile Maximum
baseline 24.70 29.28 44 44. 05 53.08 58.60
21 mm Hg 11.80 19.80 21. 20 21 28.93 42.10
41 mm Hg 0.0 4.950 8. 800 8 13.38 18.60
60 mm Hg 0.0 0.0 0.0 0 0.0 0.0
Figure 2. venous reflux measured in baseline conditions, without any compression, and after application of inelastic compression exerting different supine pressure.
from a small group of patients confirm data reported in previous papers where compression was applied with low and moderate pressure. Applying the bandages with a reduced pressure of 40 mm Hg we observed that inelastic- is significantly more effective than elastic compression in increasing EF.14 Compared to baseline assessment, without any compression, EF improved by 33% with elastic material and by 90% with inelastic material. Only with inelastic material EF was restored into its normal range, which is higher than 60%.14 EF improvement
In mixed ulcers compression therapy cannot be applied with the same strong pressure usually exerted in venous ulcers. Compression pressure must always be lower than the perfusion pressure in order not to impede the arterial inflow. In a paper on compression in mixed ulcers9 we could observe that an inelastic bandage exerting a reduced pressure up to 40 mm Hg does not hindrance but seems rather increase the arterial inflow. It could be questionable if such a reduced pressure can be effective in improving the impaired venous hemodynamics which represents the other side of the mixed ulcer pathophysiology. In the same group of patients with mixed ulcers we selected a sub-group of 14 patients who were able to perform the exercise necessary to measure the ejection fraction and applied an inelastic bandage with a pressure range of 20–30 mm Hg and of 30–40 mm Hg. Even with this reduced pressure inelastic compression increased significantly the EF. With an interface pressure of 20 to 30 mm Hg EF increased to more than 50% and with an interface pressure of 30 to 40 mm Hg EF was restored into its normal range greater than 60%. These data confirm old data coming from different papers:14–16 although strong interface pressure, higher than 60 mm Hg, produces the maximal increase of EF,15,16 every time inelastic compression was applied, even a reduced pressure of 20, 30 or 40 mm Hg was able to increase significantly the EF and restore it into its normal range when the pressure is higher than 30 mm Hg.
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Phlebology 29(1S)
supine pressure
(A)
standing pressure
(B)
80
80
70 60
50
mm Hg
mm Hg
60 40 30 20
40 20
10 0 Minimum 25% Percentile Median 75% Percentile Maximum
ref. 15 16.00 20.00 20.50 22.00 24.00
ref. 9 22.00 24.00 25.00 26.00 28.00
ref. 16 27.00 28.00 30.50 33.25 41.00
ref. 9 32.00 34.00 35.00 36.00 39.00
ref. 14 35.00 40.00 42.00 43.00 47.00
ref. 15 39.00 40.00 41.00 41.00 43.00
0 Minimum 25% Percentile Median 75% Percentile Maximum
ref. 15 20.00 33.00 36.00 40.75 51.00
ref. 9 26.00 38.00 40.00 43.00 50.00
ref. 16 34.00 44.00 49.00 53.00 59.00
ref. 9 48.00 50.00 52.00 54.00 60.00
ref. 14 59.00 60.00 63.00 68.00 71.00
ref. 15 55.00 58.00 61.00 64.75 67.00
Figure 3. (3A) Supine interface pressure in the mild and moderate range (up to 40 mm Hg); (3B) corresponding standing pressure. X axis: reference papers data are reported from.
Ejection Fraction 100
normal range 80
%
60
40
20
0
Minimum Mi i 25% Percentile Median 75% Percentile Maximum
base line
b.l.EF 15.80 23.80 32.80 37.00 50.10
compression pressure < 30 mm Hg
ref. 15 23.90 49.83 52.00 58.40 70.60
ref. 9 40.20 52.00 54.30 56.00 64.10
compression pressure > 30 mm Hg
ref. 16 47.30 57.93 64.55 73.80 86.50
ref. 9 55.90 58.60 62.60 69.90 78.50
ref. 14 52.30 57.78 62.75 68.88 87.40
ref. 15 31.70 53.45 61.55 68.80 89.40
Figure 4. Ejection Fraction corresponding to pressure ranges as reported in Figure. 3. EF is significantly improved compared to average baseline EF, without any compression, even with a compression pressure lower than 30 mm Hg. EF is restored into its normal range (>60%) when the compression pressure is higher than 30 mm Hg. X axis: reference papers data on EF are reported from. b.l. EF: baseline EF.
Venous reflux was not directly studied in patients with mixed ulcers but only in patients with venous insufficiency even if those results may reasonably be extended to patients with mixed ulcers: strong pressure can achieve the best effectiveness in reducing/abolishing venous reflux but also lower pressure ranges, when
exerted by inelastic material, are able to reduce significantly the venous reflux.11,12 The reported data could seem in contradiction with results from other papers. It is well known that compression therapy is able to improve the venous hemodynamics by reducing up to occluding the venous system. The compression pressure necessary to influence the venous diameter depends on the body position. In supine position a low pressure of 20 mm Hg is enough to occlude the venous lumen. The compression pressure necessary to interfere with the venous diameter rises to about 50 mm Hg in sitting position and must exceed 60 mm Hg when the patients stands up and walks.20,21 These data could support the hypothesis that a supine pressure of 40 mm Hg is not enough to improve the venous hemodynamics when the patient stands up. But it must be taken into account that, when exerted by inelastic material, the pressure rises significantly from the supine to the standing position and during exercise. With this material a supine pressure of 40 mm Hg may easily rise to more than 60 mm Hg in standing position being able to interfere with the venous diameter by approaching or overcoming the intravenous pressure so improving the venous hemodynamics. An intermittent occlusion of the incompetent veins at every step is able to restore a kind of artificial valve mechanism22 making possible the reduction/abolition of venous reflux and the improvement on EF. Elastic material exerts a standing pressure which is only slightly higher than the supine pressure; its SSI and WPA are very low as their ‘‘massaging effect’’.
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Mosti
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These characteristics make elastic material significantly less effective in reducing venous reflux and increasing EF11,12,14–16 and not effective enough with a reduced pressure.
Conclusion In patients with mixed ulcers a ‘‘reduced’’ or ‘‘modified’’ compression pressure of 40 mm Hg in supine position, when exerted by an inelastic bandage, is able to significantly improve the impaired venous hemodynamics without impeding the arterial inflow. Conflict of interest The authors has no conflict of interest and nothing to disclose.
Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
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