Table of Contents  
Year : 2021  |  Volume : 8  |  Issue : 1  |  Page : 29-34

Ultrasound color duplex parameters of patients presenting with lower limb varicose veins at outpatient department of university hospital of Nepal

Department of Surgery (CTVS-Unit), Kathmandu University, Dhulikhel, Nepal

Date of Submission02-Feb-2020
Date of Acceptance18-Feb-2020
Date of Web Publication20-Feb-2021

Correspondence Address:
Amit Kumar Singh
Department of Surgery (CTVS-Unit), Kathmandu University, Dhulikhel
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijves.ijves_11_20

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Background: Varicose vein is prominent dilated veins of lower limbs. Incomplete treatment and local recurrence are still the clinical challenge among the vascular surgeons. We aim to evaluate the range of imaging on color duplex describing the anatomy of veins, their variants, valve competencies, territories of defective venous system, demographic data, and the factors contributing among the patients referred to Vascular Outpatient Department of Kathmandu University Hospital. Objective: The aim was to know the ultrasound (US) color duplex parameters of superficial venous system in varicose vein. Materials and Methods: We included 299 patients during the study of 6 months with varicose veins for detailed US Doppler analysis. Gray-scale US was done to study the anatomy of veins followed by color duplex and color duplex spectrometry to determine the reflux of the superficial venous system. Quantification of reflux was determined by the use of Valsalva maneuver. Association of great saphenous vein (GSV) cross-sectional diameter and saphenofemoral junction incompetence was also studied. Results: Of 299 varicose vein cases, 52.50% were female. Among involved cases, the mean of GSV diameter was 5.43 mm in the right and 5.68 mm in the left. Saphenofemoral junction diameter was 7.89 mm in the right and 8.17 mm in the left. Receiver operative characteristics curve showed GSV diameter at femoral condyl of 4.5 mm as best cutoff value for the diagnosis saphenofemoral junction reflux. Conclusions: US color duplex is investigation of choice for varicose vein as a preoperative analysis tool, quantifying the superficial valve incompetency, studying and mapping the venous anatomy, and planning the surgery.

Keywords: Nepal, saphenofemoral junction competency, ultrasound Doppler, varicose veins

How to cite this article:
Singh AK, Karmacharya RM, Vaidya S, Thapa P, Bhatta G. Ultrasound color duplex parameters of patients presenting with lower limb varicose veins at outpatient department of university hospital of Nepal. Indian J Vasc Endovasc Surg 2021;8:29-34

How to cite this URL:
Singh AK, Karmacharya RM, Vaidya S, Thapa P, Bhatta G. Ultrasound color duplex parameters of patients presenting with lower limb varicose veins at outpatient department of university hospital of Nepal. Indian J Vasc Endovasc Surg [serial online] 2021 [cited 2021 Feb 26];8:29-34. Available from:

  Introduction Top

Varicose vein is prominent dilated veins usually in the lower limb and is associated with pain, pigmentation, discomfort, and sometimes ulceration.[1] This is one of the most common problem that the patient visits in vascular outpatient department (OPD).[2] It is a very common problem in Western population, however, one study among traffic police of Nepal related to disease prevalence has been done in Nepal, which shows a prevalence of 12%.[3] In Western studies, approximately 15% of men and 25% of women of the general population have been documented to get affected by varicose veins.[1]

Different options of treatment of varicose veins are under practice; however, incomplete treatment and local recurrence is still the clinical challenge among the vascular surgeons.[4] Since long back, the effort has been made to deal with the problem, it is still disappointing to get high recurrence rate, and this seems due to inadequate investigations before the surgery.[5]

Ultrasound (US) color duplex has been standard in assessing morphology and hemodynamics of lower limb veins. Whatever procedure we plan to do, whether it is radiofrequency ablation (RFA), endovenous laser ablation, or foam sclerotherapy; US Doppler becomes the gold standard modality of investigation.[4]

The preoperative evaluation is very important to plan the treatment of varicose veins. Good knowledge of the anatomy and the pathophysiology of different valves, presence or absence of incompetent perforators are very important in treatments of varicose vein. Before the invention of US duplex, invasive venography and clinical examination were only options for the evaluation of varicose vein. However, now with the invention of US color duplex, it is safe, noninvasive, with no radiation hazard, and easily available modality of investigation.[6]

Detailed and systematic record of Doppler parameters of patients suffering from lower limb varicose veins help in complete diagnosis of the condition, make surgical plans better, and help in appropriate treatment of the condition. Many consensuses have been published on the Doppler parameters. GSV diameter at the level of the femoral condyle as ≥5 mm for both male and female has high sensitivity and specificity to predict saphenofemoral junction (SFJ) reflux.[7] Quantification of the superficial venous reflux can be best assessed using ultrasonography (USG) color duplex spectrometer against forced Valsalva maneuver. Venous insufficiency is found in limbs with high reflux velocity (>30 cm/s)[8] and reflux time (RT) ≥500 ms.[9]

We present our finding of Doppler parameter in varicose veins cases following protocol-based assessment. Detailed description of in-depth Doppler parameter is still inadequate in our country, and thus, we aim to study the Doppler parameters in detail. The pathological perforators are those with reflux reverse flow of ≥500 ms and diameter of ≥3.5 mm.[10]

Aims and objectives

The aim was to know the US color duplex parameters of patients with the diagnosis of the lower limb varicose vein.

  Materials and Methods Top

This is a hospital-based observational study conducted after getting ethical clearance from the Institutional Review Committee. Consecutive patients who were referred to vascular OPD during the period from July 2019 to December 2019 for Color Doppler and preoperative assessment were studied. Anatomy of the veins of lower extremity and their pathophysiology were studied. Involvement of different venous system and perforators was studied in detail. All the cases that we studied during this period had clinical varicose vein and were examined as a preoperative case.

All cases of clinical varicose veins that were either referred to or were evaluated as a preoperative assessment during the study were included in the study. Previously operated varicose veins, presence of deep-vein thrombosis (DVT) and/or superficial thrombophlebitis, patient with pregnancy and patient with vascular malformations were not included in the study.

This study is a census sampling, which included all the cases that meet the selection criteria during the study. A total of 299 patients were enrolled in the study, and all these cases underwent Doppler USG of lower limb using Siemens Acuson P300 US machine and Kalamed US using linear transducer probe of 5–12 MHz. These patients underwent color duplex scanning in standing position over the “Doppler stand.” The “Doppler stand” is a customized square box that is 20 height from the ground level so that there is better ergonomics during Doppler USG. The color duplex was started with measurement of great saphenous vein (GSV) diameter [Figure 1] which is taken at the level of the femoral condyle in B-mode. In case of the presence of branch or distal insufficiency point is seen, measurements were taken at the segment before its branching. After the GSV diameters were measured, all these cases had Doppler USG at SFJ [Figure 2] to note the diameter and reflux. Reflux was defined by the presence of reflux seen after forced Valsalva maneuver. Reflux was quantified, and the patients with RT ≥ 500 ms and/or peak reflux velocity (PRV) more than 30 cm/s were tagged as reflux positive [Figure 3]. Reflux positive groups were classified into two groups: partial competent (if either of one parameter is positive) and incompetent (if both the parameters are positive). After this, other venous anatomy variations were scanned, perforators were identified, and any perforators more than 3.5 mm were tagged as significant perforators [Figure 4]. Similarly, short saphenous vein (SSV) diameter was measured in popliteal fossa followed by saphenopopliteal junction (SPJ) diameter. SPJ competency was also examined by spectral Doppler after squeezing the calf. At the end of the examination, the absence of DVT and superficial thrombophlebitis was confirmed.
Figure 1: Ultrasound duplex showing cross-sectional view of great saphenous veins measured at the level of femoral condyle

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Figure 2: Ultrasound duplex scan showing saphenofemoral junction

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Figure 3: Ultrasound color duplex spectrometry showing reflux velocity and reflux time measured after forced Valsalva maneuver in standing position

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Figure 4: Ultrasound color duplex scan showing perforator vein

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  Results Top

During this study, we conducted a study on 299 patients with varicose veins. Among the cases, 47.50% (142) were male, and 52.50% (157) were female. Varicose veins were commonly observed in the age group of 30–60 years (67.25%), and the least common in the age group ≥60 years (12.73%). There were 249 patients (83.27%) with occupation where they had to stand up for ≥6 h. These facts are tabulated in [Table 1].
Table 1: Patient characteristics

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A total of 209 (69.89%) patients underwent RFA either unilateral or bilateral with or without SPJ ligation. Among RFA cases, 61 (29.18%) underwent right RFA, 81 (38.68%) cases underwent left RFA, and 67 (32.04%) cases underwent bilateral RFA. SPJ ligation either unilateral or bilateral was done in 99 (33.11%) patients with or without RFA. Among SPJ ligation, 39 (39.39%) underwent the right SPJ ligation, 41 (41.41%) underwent the left SPJ ligation, and 19 (19.19%) underwent bilateral SPJ ligation. There were 30 cases among 299 who underwent purely only SPJ ligation without RFA or perforator ligation.

There were 43 (14.38%) cases where perforators were only present as the culprit for varicose veins. These cases had no problems with SFJ incompetence or SPJ incompetence; thus, perforator ligation was only done without RFA and/or SPJ ligation. During the scanning of 299 patients (598 limbs), we found 191 perforators. These perforators were associated with SFJ incompetence and or SPJ incompetence. Of which, the most common site of perforator was mid-calf. There were 117 (48.41%) mid-calf perforator ligation followed by above ankle 56 (23.14%) perforators.

On US color duplex scanning [Table 2], among the patients with right varicose vein in GSV system; the mean cross-sectional diameter of the right GSV was 5.43 mm, SFJ was 7.89 mm, mean right SFJ RT was 347.80 ms, and mean right SFJ velocity was 41.71 cm/s. Similarly, among patients with the left varicose vein in the GSV system; the mean cross-sectional diameter of left GSV was 5.68 mm, left SFJ was 8.17 mm, left SFJ RT was 400.70 ms, and left SFJ reflux velocity was 47.70 cm/s.
Table 2: Duplex derived parameters of great saphenous venous system

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US color duplex scanning is done in case of varicose veins in SSV system, mean cross-sectional diameter of left SSV was 5.41 mm, left SPJ was 5.27 mm, right SSV was 5.21 mm, and right SPJ was 4.96 mm. A GSV diameter threshold of 4.50 mm or above had the best value for predicting reflux. The sensitivity and specificity at GSV diameter of 4.50 mm to predict the SFJ incompetence were 82% and 70.8%, respectively, as shown in [Figure 5].
Figure 5: Receiver operating characteristics curve analysis for determining best cutoff value for diagnosing saphenofemoral junction reflux. For great saphenous vein, 4.5 mm measured at femoral condyl, or within 5 cm from the femoral condyl was best cutoff value to predict the saphenofemoral junction reflux with broadest area under of curve (0.768)

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  Discussion Top

Peripheral veins can be affected by many disorders and these can be assessed by an US. The evaluation of varicose veins is considered gold standard using US color duplex scanning in standing position.[2] Varicose veins are usually seen in GSVs due to venous incompetence. In general, SFJ incompetence is believed to be the underlying cause, but varicose veins occur even without reflux at SFJ, and the question is raised about the cause of varicose veins. This also leaves with queries that can venous incompetence start at any point and are the significant perforators also the cause of varicose veins?[11] Localization of incompetency is very important and probably must need effort to avoid recurrence and plan the surgery. Despite many clinical methods in practice to evaluate varicose veins, the study suggests that the clinical methods are unreliable, and color duplex scan has great accuracy in diagnosis the reflux sites.[6] In this study, thus we wanted to evaluate the cases of varicose veins in details of its anatomy, Valvular function, and probable cause of varicose veins.

This disease condition is found to be more common in the female population.[1] This female predominance is said to be attributed to hormonal factors and physiological changes in female development.[12] Our finding is also similar to this study. In our study series, 52.5% (157) were female, and 47.5% (142) were male. However, a study done in Nepal showed male predominance (70.37%) in the occurrence of varicose veins.[13] Similarly, the study done in India also showed male predominance, and the study claimed it to be due to a lesser number of affected Indian women seeking for medical help.[12] There are two studies in the literature that shows no sex differences in the prevalence of varicose veins.[14],[15]

The age of the patient with varicose veins in the study series was 18–85 years, with a mean age being 44.38 years. Of total 299 patients, the most common affected age group was 30–60 years (67.2%), and the least was >60 years (12.7%). A randomized trial study was done in 2002 on real epidemiology of varicose veins, which reported that venous abnormalities increase with progressing age.[16] Different other studies done show the highest rate of occurrence in the age group of 40–50 years of age and least in the age group of 20–29 years.[17]

Farming, security persons, pregnancy, and obesity are one of the most common risk factors for varicose veins.[18] In our study, we found farmers (67.2%) being affected with varicose veins. This could be due to the reason that Nepal is an agricultural country. Occupation demanding standing or walking for a prolonged period, that is, >6 h/day was associated with a higher risk for varicose vein in our study. Among 299 patients, 83.3% of patients had occupation that demanded walking or standing for ≥6 h per day. A longitudinal study done on 851 patients who underwent first-time surgery for varicose veins suggested an increased risk in relation to prolonged walking/standing (6 h/day) and heavy lifting.[19],[20] However, other studies have shown no relationship between lengthy period of standing and the occurrence of varicose veins.[21]

We found left-sided involvement was more than the right side. This involvement was true for GSV as well as SSV. Left limb was involved in 58.2% of the study group. We thought this could be due to longer GSV in the left and left iliac artery crossing over the left iliac vein. However, there are studies in the literature, which shows no difference between site involved.[22],[23]

Among 299 patients, GSV was involved in 209 limbs (69.89%), SSV was involved in 99 (33.11%) cases, and significant perforator without the involvement of GSV and or SSV was present in 43 (14.38%) cases. We found 191 significant perforators at different sites during scanning of 598 limbs, but only 43 of them were the independent culprit to cause varicose vein, and the rest was in association with SFJ incompetency or SPJ incompetency. These 43-independent culprit perforators were ligated. Remaining 148 perforators were treated in adjunction to RFA or SPJ ligation. In cases that underwent RFA, if RFA cannulation was possible distal to the perforation site; we did ablate the perforator with RFA, and incase cannulation was done cephalic to perforator, we did perforator ligation separately. Culprits in associations with SPJ incompetence were ligated separately during SPJ ligation. SFJ incompetency (69.89%), SSV incompetency (33.11%), and both SFJ and SPJ competent in the case of varicose vein were 14.38%. This is very similar to the findings demonstrated by Hanrahan et al.[24]

In this study, we evaluated 299 patients (598 Limbs) with US color duplex scanning. In the cases, where the right limb was clinically diagnosed to have varicose vein in the GSV system (128 limbs), the mean GSV measured at the level of femoral condyl or 5 cm within the femoral condyl or before GSV gives major branching was 5.43 mm. We also measured the safenofemoral Junction diameter on standing position, and the mean value of right SFJ cross section diameter was 7.89 mm. All these cases had SFJ incompetence which was tagged by the eflux velocity of >30 cm/s or RT of >500 ms or both.

Similarly, of 148 left SFJ incompetent limbs, mean GSV measured at the level of femoral condyl or 5 cm within the femoral condyl or before GSV gives major branching was 5.68 mm, and left SFJ cross section diameter was 8.17 mm.

We can find several studies in the literature done to set the cutoff value for the normal diameter of GSV. In a study, GSV value ≥7 mm in SFJ, ≥4 mm in thigh, and ≥4 mm in mid-calf could predict the SFJ incompetence.[25] In our study, we measured the GSV as proposed in the protocol, which we derived from our previous series publication of 163 diseased limbs and 131 control limbs.[7] In our previous series, we found that the cutoff value of GSV at the level of femoral condyle >5 mm for both male and female with good sensitivity and specificity.[7] In this study, best cutoff value for diagnosing SFJ reflux came to be 4.5 mm measured at femoral condyl or within 5 cm from the femoral condyl with broadest area under of curve (0.768). The sensitivity and specificity of GSV diameter of 4.5 mm measured over the femoral condyl was 82.8% and 70.8%, respectively. In a similar study done by Navarro et al., they found that the cutoff value of GSV was 5.5 mm or more with the sensitivity of 78% and specificity of 87% with an accuracy of diagnosis being 85%.[26]

There are many studies done in the past, which tried to find correlation between PRV and RT with competency with that peripheral valve. In 1990s, Weingarten demonstrated that in cases of severe chronic venous insufficiency, the RT is larger but he did not mention the increased time.[27] In a study done in Tokyo over 146 patients documented PRV over 30 cm/s was associated with venous incompetence.[28] The latest study done by the same group of authors in Tokyo over 2160 limbs; mean RT at SFJ was 465 ms, and PRV was 26.2 cm/s.[8] In our study group, the PRV was consistently over 30 cm/s. This was also advised by the largest study done on peripheral reflux, but our study result over RT did not match this study.[8] We think that this discrepancy is because of difficulty in making Nepalese patients understand forceful Valsalva Maneuver. While doing the maneuver PRV was easy to measure but time varied because of failure doing the right maneuver. However, this difficulty has not been mentioned in any study in the past but due to the literacy level of Nepalese patients, we assume this could be the major reason. Studies have stated that it is very difficult to make people understand this maneuver and also if done it is not comparable between two centers studies.[29] There are many ways of doing this maneuver, and thus, results may vary from different patients, studies, and centers.[30]

Trials with a higher number of patients, following the exact method of Valsalva and use of US can be used to quantify the RT and PRV to discuss on SFJ incompetency in the near future.

  Conclusions Top

US color duplex is the gold standard investigation of choice in the case of varicose vein as a preoperative analysis tool, quantifying the superficial valve incompetency, studying and mapping the venous anatomy, and planning surgery. This investigation tool can be used to find out independent culprit vessels, which could cause recurrence if only RFA or SPJ ligation was done. We also suggest that GSV value measured at the level of femoral condyl ≥ 4.5 mm can predict venous reflux with sensitivity and specificity of 82.8 and 70.8 with the highest area of coverage in receiver operative characteristics. The quantification of PRV seems to be more consistent than RT in determining the superficial venous reflux in Nepalese patients.


The authors would like to thank Department of Radiology, Dhulikhel Hospital; Kathmandu University Hospital. They have always been supporting when we had confusions on any Doppler evaluation so that we do not record any wrong information and data. The authors would also like to thank Dr. Bala Ram Malla, HOD of Department of Surgery and Prof Dr. Ram Kantha Makaju, Vice-Chancellor of Kathmandu University for continuously encouraging Department of Cardiothoracic and Vascular Surgery. Last but not the least, authors would like to thank my family members for continuously supporting me.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Callam MJ. Epidemiology of varicose veins. Br J Surg 1994;81:167-73.  Back to cited text no. 1
De Maeseneer M, Pichot O, Cavezzi A, Earnshaw J, van Rij A, Lurie F, et al. Duplex ultrasound investigation of the veins of the lower limbs after treatment for varicose veins – UIP consensus document. Eur J Vasc Endovasc Surg 2011;42:89-102.  Back to cited text no. 2
Karmacharya RM, Prajapati L, Rai S. Risk assessment of varicose veins among the traffic police of Kathmandu Metropolitan city, Nepal. Indian J Vasc Endovasc Surg 2019;6:107.  Back to cited text no. 3
Zwiebel WJ, Pellerito JS. Tricky and interesting carotid cases. Ultrasound Q 2005;21:113-22.  Back to cited text no. 4
Houghton AD, Panayiotopoulos Y, Taylor PR. Practical management of primary varicose veins. Br J Clin Pract 1996;50:103-5.  Back to cited text no. 5
Dixon PM. Duplex ultrasound in the pre-operative assessment of varicose veins. Australas Radiol 1996;40:416-21.  Back to cited text no. 6
Karmacharya RM, Shrestha BK, Shrestha B. Prediction of saphenofemoral junction incompetence by measurement of great saphenous vein size at the level of femoral condyle. Indian J Vasc Endovasc Surg 2018;5:92.  Back to cited text no. 7
  [Full text]  
Konoeda H, Yamaki T, Hamahata A, Ochi M, Sakurai H. Quantification of superficial venous reflux by duplex ultrasound-role of reflux velocity in the assessment the clinical stage of chronic venous insufficiency. Ann Vasc Dis 2014;7:376-82.  Back to cited text no. 8
Labropoulos N, Tiongson J, Pryor L, Tassiopoulos AK, Kang SS, Ashraf Mansour M, et al. Definition of venous reflux in lower-extremity veins. J Vasc Surg 2003;38:793-8.  Back to cited text no. 9
Kuyumcu G, Salazar GM, Prabhakar AM, Ganguli S. Minimally invasive treatments for perforator vein insufficiency. Cardiovasc Diagn Ther 2016;6:593-8.  Back to cited text no. 10
Abu-Own A, Scurr JH, Coleridge Smith PD. Saphenous vein reflux without incompetence at the saphenofemoral junction. Br J Surg 1994;81:1452-4.  Back to cited text no. 11
Irodi A, Keshava SN, Agarwal S, Korah IP, Sadhu D. Ultrasound Doppler evaluation of the pattern of involvement of varicose veins in Indian patients. Indian J Surg 2011;73:125-30.  Back to cited text no. 12
Shah S, Koirala S, Pradhan S, Pradhan A. Surgical outcomes of varicose veins at universal college of medical sciences, Bhairahawa, Nepal. J Univers Col Med Sci 2016;4:14-6.  Back to cited text no. 13
Beaglehole R. Epidemiology of varicose veins. World J Surg 1986;10:898-902.  Back to cited text no. 14
Komsuoglu B, Göldeli O, Kulan K, Cetinarslan B, Komsuoglu SS. Prevalence and risk factors of varicose veins in an elderly population. Gerontology 1994;40:25-31.  Back to cited text no. 15
Cesarone MR, Belcaro G, Nicolaides AN, Geroulakos G, Griffin M, Incandela L, et al. 'Real'epidemiology of varicose veins and chronic venous diseases: The San Valentino Vascular Screening Project. Angiology 2002;53:119-30.  Back to cited text no. 16
Narra RK, Vuyyuru S, Bhimeswara Rao P, Putcha A. Role of colour flow duplex sonography in evaluation of varicose veins of lower limbs. J Evid Based Med Healthc 2018;5:3358-62.  Back to cited text no. 17
Lee AJ, Evans CJ, Allan PL, Ruckley CV, Fowkes FG. Lifestyle factors and the risk of varicose veins: Edinburgh Vein Study. J Clin Epidemiol 2003;56:171-9.  Back to cited text no. 18
Tabatabaeifar S, Frost P, Andersen JH, Jensen LD, Thomsen JF, Svendsen SW. Varicose veins in the lower extremities in relation to occupational mechanical exposures: A longitudinal study. Occup Environ Med 2015;72:330-7.  Back to cited text no. 19
Tüchsen F, Hannerz H, Burr H, Krause N. Prolonged standing at work and hospitalisation due to varicose veins: A 12 year prospective study of the Danish population. Occup Environ Med 2005;62:847-50.  Back to cited text no. 20
Canonico S, Gallo C, Paolisso G, Pacifico F, Signoriello G, Sciaudone G, et al. Prevalence of varicose veins in an Italian elderly population. Angiology 1998;49:129-35.  Back to cited text no. 21
Bechsgaard T, Hansen KL, Brandt A, Moshavegh R, Forman JL, Føgh P, et al. Evaluation of peak reflux velocities with vector flow imaging and spectral Doppler ultrasound in varicose veins. Ultrasound Int Open 2018;4:E91-8.  Back to cited text no. 22
Robertson L, Evans CA, Fowkes FG. Epidemiology of chronic venous disease. Phlebology 2008;23:103-11.  Back to cited text no. 23
Hanrahan LM, Kechejian GJ, Cordts PR, Rodriguez AA, Araki CA, LaMorte WW, et al. Patterns of venous insufficiency in patients with varicose veins. Arch Surg 1991;126:687-90.  Back to cited text no. 24
Engelhorn C, Engelhorn A, Salles-Cunha S, Picheth F, Castro N, Dabul N, et al. Relationship between reflux and greater saphenous vein diameter. J Vasc Technol 1997;21:167-74.  Back to cited text no. 25
Navarro TP, Delis KT, Ribeiro AP. Clinical and hemodynamic significance of the greater saphenous vein diameter in chronic venous insufficiency. Arch Surg 2002;137:1233-7.  Back to cited text no. 26
Weingarten MS, Czeredarczuk M, Scovell S, Branas CC, Mignogna GM, Wolferth CC Jr. A correlation of air plethysmography and color-flow-assisted duplex scanning in the quantification of chronic venous insufficiency. J Vasc Surg 1996;24:750-4.  Back to cited text no. 27
Yamaki T, Nozaki M, Sasaki K. Quantitative assessment of superficial venous insufficiency using duplex ultrasound and air plethysmography. Dermatol Surg 2000;26:644-8.  Back to cited text no. 28
Ricci S, Moro L, Minotti GC, Incalzi RA, De Maeseneer M. Valsalva maneuver in phlebologic practice. Phlebology 2018;33:75-83.  Back to cited text no. 29
Jeanneret C, Labs KH, Aschwanden M, Bollinger A, Hoffmann U, Jäger K. Physiological reflux and venous diameter change in the proximal lower limb veins during a standardised Valsalva manoeuvre. Eur J Vasc Endovasc Surg 1999;17:398-403.  Back to cited text no. 30


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

  [Table 1], [Table 2]


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