Correlation between reflux time and venous clinical severity score in patients undergoing saphenous vein ablation: A prospective study

Introduction

Superficial venous insufficiency is common and can be accompanied by debilitating symptoms, including leg heaviness, aching, fatigue, edema, and ulceration.^1–3 These symptoms can be associated with venous reflux in particular of the great saphenous vein (GSV).^3–5 In cases of symptomatic saphenous vein reflux, the incompetent vein can be permanently ablated as a therapeutic measure.^6,7 There are a number of thermal and non-thermal minimally invasive techniques available to ablate the incompetent saphenous vein, including radiofrequency ablation (RFA) and cyanoacrylate closure (CAC).^8,9

Duplex ultrasound can be utilized to diagnose reflux.^10,11 The test is often performed with the patient standing or in the reverse Trendelenburg position. ¹² The examiner performs provocative maneuvers such as external calf compression to promote antegrade venous flow through the valves. ¹³ With rapid decompression an effective suction effect is created that can promote retrograde blood flow. Whereas functional venous valves will coapt to minimize this, incompetent valves will not, contributing to observable venous reflux on doppler studies. ¹⁴ The duration of time the observed venous valve demonstrates retrograde flow is referred to as reflux time. Reflux time was previously referred to by some as valve closure time. However, as retrograde flow may cease without valve closure, reflux time is a more representative term. ¹⁵ Venous reflux times in the GSV are considered to be “abnormal” for values exceeding 0.5 s.^13,14

The relationship between the duration of venous reflux (reflux time) and severity of symptoms is unclear. In this prospective study, we sought to compare venous reflux time and venous clinical severity score (VCSS).

Methods

Patients presenting for treatment of symptomatic venous reflux to two operators at a teaching hospital, were prospectively enrolled between August 2020 and January 2022. The venous clinical severity score (VCSS) was conducted by the operating physicians as part of the initial screening visit or immediately before the ablation. The CEAP (Clinical-Etiology-Anatomy-Pathophysiology) classification utilized was based on the 2004 revision. ¹⁶ All patients underwent ablation as planned. Study participants had not been intervened upon prior to participation in this study. Participants were ambulatory and did not possess significant pedal or ankle pathology that hindered mobility.

The utilized ultrasound protocol collected data on the presence and duration of reflux at multiple segments of the GSV including proximal, mid, distal, knee, and calf. Patients were typically evaluated in the reverse Trendelenburg position (30°). Due to occasional episodes of patient unsteadiness and syncope during prolonged standing, our ultrasound laboratories do not routinely perform reflux studies in the standing position. For the purpose of analysis, the longest reflux time was utilized.

SPSS software (IBM, Armonk, NY) was used for statistical analysis. Great saphenous vein reflux time versus VCSS scores demonstrated nonparametric distribution and correlations were determined using the Spearman rank correlation method. Mean VCSS values were compared using the t-test.

The work complied with the Declaration of Helsinki. Institutional review board approval was obtained for the study.

Results

Eighty patients (mean age 64+/−12.7 years, 56% female) undergoing great saphenous vein (GSV) ablation for symptomatic reflux were evaluated prospectively. Procedural and symptom score data are shown in Table 1 and patient co-morbidities in Table 2.

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Table 1.

Patient and procedural characteristics.

BMI	CEAP	VCSS	Reflux time max	Left GSV, %	Ablation modality
33.2 (7.2)	3.0 (1.3)	(7.4) 3.7	5.3 (3.3)	54	RFA 70%
					CAC 30%

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Table 2.

Patient medical co-morbidities and smoking status.

DM, %	CVA, %	HTN, %	DVT, %	CHF, %	CKD, %	PAD, %	Smoker
24	10	59	10	11	10	4	Active 5%
							Former 48%
							Never 53%

CVA: cerebrovascular accident (history); DM: diabetes mellitus; HTN: Hypertension; DVT: Deep vein thrombosis (history), congestive heart failure; CKD: chronic kidney disease; PAD: peripheral arterial disease.

In addition to GSV reflux, 14 (17.5%) had femoral vein reflux, 6 (7.5%) had popliteal vein reflux, and 14 (17.5%) had both femoral and popliteal vein reflux on the pre-procedural ultrasound. In other words, 42.5% of the study population had some form of concomitant deep vein reflux in the same limb.

VCSS values ranged from 2 to 20 (median 7). Mean reflux time was 5.3 s (+/−3.3). A scatter plot of reflux time against VCSS is shown in Figure 1. The Spearman rank correlation yielded a value of rs = −0.123, p (2-tailed) = .279, which was not significant.OPEN IN VIEWER

Among the patients without deep vein reflux the mean VCSS was 6.4 and mean reflux time 5.2 s. Among patients with deep vein reflux the mean VCSS was 8.7, mean reflux time 5.4 s. Mean VCSS was significantly higher in the group with deep reflux (p < .05). Analysis of patients with only superficial vein reflux (n = 45) also demonstrated a poor correlation between VCSS and reflux time (r _s = −0.051, p (2-tailed) = .741).

Discussion

To better quantify the burden of venous disease severity on quality of life and to measure treatment efficacy over time, a number of scores have been proposed. The VCSS is one such available disease-specific score.^17,18 The VCSS has been utilized and evaluated in a number of venous intervention trials. ¹⁹ In a prospective evaluation of patients with varicose veins, the VCSS correlated strongly with two other scores, the Aberdeen Varicose Vein Questionnaire (AVVQ) and the Chronic Venous Insufficiency quality of life Questionnaire (CIVIQ-14) CIVIQ-14 scores (r = 0.7, p < .0001). ²⁰

In order to evaluate venous flow in the leg, a number of techniques have been proposed. The volume arterial flow index utilizes pulsed wave doppler to measure venous volume flow out of the leg and compare it to the arterial inflow.^21,22 The recirculation index utilizes pulsed wave doppler to compare antegrade versus retrograde saphenous volume during calf compression and decompression.^21,23 Venous filling time uses air plethysmography to measure calf refilling with faster filling obtained in the setting of reflux. ²⁴ Postural diameter change utilizes duplex ultrasound to compare saphenous vein diameter between standing and lying. ²⁵ However, the two measurements that have been the most broadly adopted are saphenous vein diameter and reflux (presence and duration).^{10,11,13,14,26} Reflux time represents the time taken to fill the calf venous reservoir in an incompetent venous system.

The relationship between symptoms and reflux time has been previously evaluated in a few studies. Neglén et al. ¹⁵ retrospectively reviewed reflux time against CEAP score and hemodynamic parameters such as ambulatory venous pressure, peak reflux velocity, and venous filling time. No meaningful correlation was found with reflux time and clinical or hemodynamic parameters. Contradicting results were reported by Yang et al. who prospectively evaluated 531 patients with symptomatic venous insufficiency in China. ²⁷ The authors noted a strong correlation between reflux time and VCSS scores (r² = 0.82). Ultrasound was performed in all patients in the standing position. An obvious strength of the study was its large sample size. A limitation may be the accurate interpretation of the ultrasound studies. By the authors’ own admission, in China a significant number of reflux cases have been diagnosed by venography. Also it was stated “the majority of Chinese vascular surgeons are not versatile in vascular ultrasound examination” and “venous ultrasound protocols varied from institution to institution.”

In a study of 48 patients with venous insufficiency, reflux volume was related to the ejected volume of blood during calf compression-decompression. ²⁸ Reflux volume likely incorporated both the reflux time and flow rate, both of which probably reflected the size of the venous reservoir that exists in the lower leg. In another study, venous filling time was found to correlate well with reflux time. ²⁴

In our study, reflux testing was performed in the reverse Trendelenburg position and not in the upright. In a very interesting publication, Tauraginskii et al. ²⁹ evaluated 61 limbs with great saphenous reflux in 3 positions: standing, laying flat, and seated upright with legs stretched out. An automatic cuff was used for calf compression-decompression. Reflux was elicited amongst 100% of limbs in the standing and seated upright positions. Interestingly, in 91.8% of cases reflux was also noted in the laying flat position. Two observations might be made by this study: first, that requiring the subject to stand is often not mandatory and second, forces other than gravitation play a role in reflux. The observation that non-gravitational forces play a role has also been made in other studies. ³⁰ The size of the calf reservoir may be a key factor. ²⁹

There are several potential confounders to our findings including concomitant deep vein reflux. Thirty-four (42.5%) of study participants did have deep vein reflux and patients with deep vein reflux did show significantly higher VCSS. Neglén, however, did not find popliteal reflux to correlate with symptom severity. ¹⁵

The diameter of the GSV was not evaluated in this study. Navarro et al. evaluated 85 patients with GSV reflux and found GSV diameter to correlate with baseline CEAP score and degree of reflux. ³¹ Gibson et al. evaluated venous symptom scores in 91 patients with reflux using data from two separate trials. Maximal GSV diameter was measured within 5 cm of the SFJ with the patient standing. Venous symptom scores including VCSS were obtained. The correlation between GSV diameter and VCSS was modest (r = 0.23, p = .03). ³² Lane et al. conducted a prospective cohort evaluation of 330 patients with symptomatic varicose veins. Saphenous vein diameter statistically correlated with VCSS (p = .041), however, the effect size was very small (partial η² = 0.018). ³³

The length of the refluxing segment within the GSV was not measured. Our past findings support the possibility that longer segments of reflux are associated with more symptomatic disease and demonstrate greater symptom resolution after ablation. ³⁴

A limitation of this study is its small size which may have led to an inability to detect correlation between reflux time and VCSS. The number and size of affected tributaries was also not evaluated, which may have impacted symptoms. The duration of the presence of symptoms was also not evaluated, which are known to progress over time.

Conclusions

In this prospective study of 80 participants undergoing GSV ablation for symptomatic reflux, maximum reflux time was not correlated with symptom severity as measured by VCSS. Reflux time is best utilized as a cutoff for the diagnosis of the presence of venous insufficiency.