Detecting Venous Reflux Using a Sixty-Degree Reverse Trendelenburg (RT-60) Position in Symptomatic Patients With Chronic Venous Disease

Abstract: Background. The optimal technique to detect venous reflux requires a patient to be standing with weight on one leg while the other leg is scanned for superficial venous reflux (standing position [SP] technique). This represents a significant hardship for a subset of patients who are unable to stand and adequately maintain their balance. This study examines the predictability of identifying venous reflux using a reverse Trendelenburg 60° (RT-60) when compared with the SP in the great saphenous vein (GSV) and small saphenous vein (SSV). Methods. After obtaining informed consent, consecutive symptomatic patients were studied for venous reflux in the GSV and SSV using both SP and RT-60 during the same visit to the diagnostic laboratory. Reflux was analyzed in both SSV (proximal, mid, and distal segments) and GSV (proximal, mid-thigh, distal-thigh, and below-the-knee segments). Reflux was defined as duration of retrograde venous flow >0.5 seconds following rapid cuff deflation. Patients with heart failure, prior limb surgery, history of deep vein thrombosis, cellulitis, known severe pulmonary hypertension, end-stage renal disease, lymphedema, or trauma were excluded. We calculated the percentage of segments that had reflux on RT-60 out of those with reflux on SP, and the percentage of no reflux on RT-60 out of those with no reflux on SP. Results. A total of 33 patients (56 limbs, 252 segments) were included in this analysis. Mean age was 65 ± 12.4 years and 54.5% were male. All patients were symptomatic (mean clinical, etiology, anatomy, pathophysiology [CEAP] class, 3.5). Deep venous reflux was present in 3/33 patients (9.1%). Of the patients enrolled, 93.9% noted worsening swelling of their lower extremities with standing up and 53.6% of limbs were CEAP class IV or higher. All limbs with no reflux on RT-60 had no reflux using the SP and 48/49 limbs (98%) with reflux on SP also had reflux on the RT-60. Conclusion. RT-60 appears to capture 98% and 100% of positive and negative reflux scans on SP, respectively, when GSV and SSV were evaluated. These findings, however, may not apply to the remainder of the venous system of the lower extremity, where SP may continue to be the standard for venous reflux evaluation. 

J INVASIVE CARDIOL 2016;28(9):370-372. 2016 July 15 (Epub ahead of print)

Key words: venous reflux, duplex ultrasound, standing technique, tilt table technique, chronic venous disease, chronic venous insufficiency, reverse Trendelenburg

The presence of venous reflux is gravity dependent and therefore patient positioning is an important step in obtaining an accurate determination of the presence or absence of reflux. The traditional and most agreed upon position is the standing position (SP), with the imaged leg in a non-weight bearing position to avoid muscular systole of the calf muscle.^1-5 This technique has been shown to be optimal in uncovering the presence of reflux, particularly in veins such as the pelvic veins connecting to the lower extremity, vein of the popliteal fossa, sciatic nerve veins, or the thigh extension of the small saphenous vein (SSV).⁶ A full comprehensive venous mapping test is needed to adequately formulate a treatment plan for patients with venous reflux and therefore the SP remains the default in our laboratory. 

Several patients, however, are not able to stand because of advanced age, muscular weakness, and severe degenerative joint disease. Several studies have shown that the tilt table test (reverse Trendelenburg [RT]) may be effective in identifying reflux in the great saphenous vein (GSV) when compared with the SP.^7,8 Most angles, however, were relatively shallow (<30°) and may not have been high enough to generate significant lower-leg hydrostatic pressure to uncover venous reflux, particularly in non-GSV superficial veins. 

This study was designed to assess a steeper angle, the RT 60° incline position (RT-60), on the presence or absence of venous reflux in both GSV and SSV in symptomatic patients with chronic venous disease. 

Methods

Patients with symptoms of chronic venous insufficiency referred for venous duplex ultrasound to Cardiovascular Medicine, PC (CVM) to evaluate for deep vein thrombosis and venous reflux were enrolled. The study was approved by the Institutional Review Board and all patients signed an informed consent. The diagnostic laboratory at CVM is accredited by the Intersocietal Accreditation Commission (IAC) for vascular testing. Two certified registered vascular technologists (American Registry for Diagnostic Medical Sonography) and one certified sonographer (Cardiovascular Credentialing International Sonographer) participated in the study. Patients needed to be able to have the study done in both the SP and RT-60 positions during the same visit. The tests were performed throughout the day for ease of scheduling. 

Procedures were performed in a standardized way. Patients underwent complete reflux study mapping in the SP after an initial standing position for 2 minutes. The non-weight bearing leg was imaged for the GSV using an anterior approach with the leg externally rotated. The SSV was imaged from behind, with the knee slightly flexed. The remainder of the veins (accessory, perforators, and tributaries) were also imaged during the SP. Following imaging in the SP position, the patient was placed supine on the tilt table. A safety belt placed around the body was used only if needed. Weight-bearing was done on one foot (the footrest can be placed unevenly so one foot can rest completely while the imaged leg is completely non-weight bearing). The table was then placed in the RT-60 position for 2 minutes before imaging. Reflux was analyzed in both the SSV (proximal, mid, and distal segments) and the GSV (proximal, mid-thigh, distal-thigh, and below-the-knee segments). Reflux was defined as duration of retrograde venous flow >0.5 seconds following rapid automatic cuff deflation. 

Patients were excluded if they had heart failure, known severe pulmonary hypertension, end-stage renal disease, lymphedema, or trauma. Limbs with prior surgery, history of deep vein thrombosis, or cellulitis were also excluded. Age, gender, CEAP (clinical, etiology, anatomy, pathophysiology) class, and presence of symptoms of chronic venous insufficiency were recorded on all patients. 

Statistical analysis. Continuous variables are described as mean ± standard deviation while nominal variables are presented as percentages. We calculated the percentage of segments that had reflux on RT-60 out of those with reflux on SP, as well as the percentage of no reflux on RT-60 out of those with no reflux on SP. 

Results    

A total of 33 symptomatic patients (56 limbs, 252 segments) were included in this analysis. Mean age was 65 ± 12.4 years and 54.5% were males. All patients were symptomatic (mean CEAP class, 3.48 ± 0.16). Table 1 shows that the majority of patients were CEAP class III and IV. Most patients were symptomatic with swelling in the lower extremity while standing, and 8.1% of patients had deep vein reflux. 

All GSV and SSV segments (n = 203) with no reflux on RT-60 had no reflux on SP and 48 out of 49 segments (98%) with reflux on SP also had reflux on the RT-60. Table 2 shows reflux duration and range between the standing and RT-60 positions. The mean reflux duration was statistically similar between the two testing positions. A numerically longer reflux duration (statistically not significant) was seen in both the proximal GSV and proximal SSV in the SP compared with the RT-60 position. The variances between the two positions were very minimal and no correlation with CEAP class, vein size, or location can be ascertained. 

Discussion

The SP method is the gold standard for evaluating reflux in patients with symptomatic chronic venous disease. The SP generates the highest hydrostatic pressure in the lower legs, maximizing the chance of identifying venous reflux. In this study, we tested the hypothesis that the RT-60 method may generate enough hydrostatic pressure to identify reflux in the GSV and SSV reliably when compared with the SP method. It should be noted that reflux does not depend only on hydrostatic pressure, but several other factors can influence its presence and shape on duplex ultrasound. This includes vein capacitance, refluxing volume, extent of varicosities, muscle pump, time of day, and presence of proximal obstruction. In this study, patients served as their own controls and both RT-60 and SP testing were done during the same setting, eliminating the impact of the time of day and vascular volume on the degree of reflux.^9,10 In this study, we have shown that the RT-60 position identified positive and negative reflux in 98% and 100% of superficial veins, respectively, when compared with the gold-standard SP position. These data apply only to the GSV and SSV segments. In other veins such as epifacial veins and varicosities, which are not supported by fascial sheaths, the findings may be different.

It should be noted, however, that a comprehensive venous test should involve all superficial veins and perforators and therefore RT-60 data in this study are limited only to the GSV and SSV. We limit the RT-60 method to patients who are unable to perform the SP, which remains our standard methodology. The SP method has been shown to be a more reliable position in the setting of a standardized test performance than the supine position.^1,5,6,10 In addition, our data apply to patients with low incidence of deep vein thrombosis despite the high proportion of patients with CEAP class IV^12,13 and higher score because patients with history of deep vein thrombosis have been excluded from this study. Therefore, our data do not apply to those patients with prior deep vein thrombosis. Furthermore, it should be emphasized that the test was performed on symptomatic patients with chronic venous disease and it is unclear how these data would apply to those with asymptomatic venous insufficiency. Finally, our data need to be validated by a larger sample of patients and with other reflux-inducing maneuvers, such as Valsalva. 

References

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From the ¹Midwest Cardiovascular Research Foundation, Davenport, Iowa; and ²Cardiovascular Medicine, PC, Davenport, Iowa.

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. The authors report no conflicts of interest regarding the content herein.

Manuscript submitted March 14, 2016, provisional acceptance given March 17, 2016, final version accepted March 21, 2016.

Address for correspondence: Nicolas W. Shammas, MD, MS, FACC, Research Director, Midwest Cardiovascular Research Foundation, 1622 E. Lombard Street, Davenport, IA 52803. Email: shammas@mchsi.com