A noninvasive screening test to detect "critical" deep venous reflux

Peripheral vascular disease assessment in the lower limb: a review of current and emerging non-invasive diagnostic methods

BACKGROUND

Worldwide, at least 200 million people are affected by peripheral vascular diseases (PVDs), including peripheral arterial disease (PAD), chronic venous insufficiency (CVI) and deep vein thrombosis (DVT). The high prevalence and serious consequences of PVDs have led to the development of several diagnostic tools and clinical guidelines to assist timely diagnosis and patient management. Given the increasing number of diagnostic methods available, a comprehensive review of available technologies is timely in order to understand their limitations and direct future development effort.

MAIN BODY

This paper reviews the available diagnostic methods for PAD, CVI, and DVT with a focus on non-invasive modalities. Each method is critically evaluated in terms of sensitivity, specificity, accuracy, ease of use, procedure time duration, and training requirements where applicable.

CONCLUSION

This review emphasizes the limitations of existing methods, highlighting a latent need for the development of new non-invasive, efficient diagnostic methods. Some newly emerging technologies are identified, in particular wearable sensors, which demonstrate considerable potential to address the need for simple, cost-effective, accurate and timely diagnosis of PVDs.

Predicting superficial venous incompetence with strain gauge plethysmography

Background

With currently available effective interventional methods to treat superficial venous insufficiency, it becomes particularly important to have a simple and reliable method to evaluate the location and severity of venous reflux. To date, there are few studies that evaluated plethysmography with and without tourniquet application to differentiate superficial from deep venous incompetence.

Objectives

To determine if strain gauge plethysmography (SGP) with and without tourniquet application can be used to distinguish between the superficial and deep venous components of venous incompetence.

Methods

We conducted a prospective study using SGP with and without tourniquet application and duplex ultrasound (duplex US) to assess the severity and location of venous incompetence in 62 patients (85 limbs, 42 women, with an age range of 32–81 years) referred to our vascular laboratory for haemodynamic evaluation. Based on duplex US results, patients were diagnosed with superficial (SVI), deep and superficial (mixed) and deep vein incompetence (DVI).

Results

Mixed incompetence was the most common type. Twenty-three out of 33 limbs in the SVI group normalized their refill rate (RR) with tourniquet application (69.6%). Normalization of the RR with tourniquet application was less common in the mixed ( n: 17 out of 40, 42.5%) and DVI ( n: 2 out of 6, 33.3%) groups.

Conclusion

SGP with tourniquet application is a simple and fast technique that can identify patients with SVI, based on RR improvement, who probably would benefit more from ablation procedures. Further studies evaluating impact of SGP with tourniquet test results on clinical outcome of SVI invasive treatment are warranted

Avaliação da bomba muscular da panturrilha em pacientes portadores de varizes primárias dos membros inferiores através da pletismografia a ar

OBJETIVO:Avaliar a influência do refluxo das veias musculares da panturrilha (surais e geniculares) na função da bomba muscular da panturrilha em pacientes com varizes primárias nos membros inferiores. MÉTODOS: Estudo transversal prospectivo, no qual os pacientes foram avaliados por meio de exame físico, mapeamento dúplexe pletismografia a ar. Foram selecionados 120 pacientes divididos em dois grupos (60 indivíduos em cada). O primeiro grupo apresentava refluxo das veias musculares da panturrilha e o segundo grupo apresentava ausência de refluxo. Cada grupo foi analisado com pletismografia a ar para estudo da função da bomba da panturrilha. As variáveis estudadas foram fração de ejeção, fração do volume residual, volume ejetado e índice de enchimento venoso para membro inferior direito e esquerdo. RESULTADOS: No grupo com refluxo, índices de fração de ejeção abaixo de 60% (com p < 0,001) foram encontrados em 82,3% (em perna esquerda) e em 74,6% (em perna direita) dos casos. Índices de fração do volume residual acima de 60% foram identificados em 62,5% (em perna esquerda, p = 0,015) e em 86,7% (em perna direita, p = 0,014) dos casos avaliados. Não houve variação estatisticamente significativa para o índice de enchimento venoso entre os grupos com e sem refluxo, com p = 0,140 e p = 0,140 para pernas esquerda e direita, respectivamente. Foram encontrados 63,6% dos pacientes com refluxo das veias da panturrilha (em perna esquerda), e 61,8% (em perna direita) com volume ejetado acima de 150 mL (p = 0,001). CONCLUSÕES: Houve alteração da bomba muscular da panturrilha, levando a uma diminuição de sua função, em ambos os membros inferiores por conseqüência da presença do refluxo das veias musculares da panturrilha (geniculares e surais).

Haemodynamic and Clinical Impact of Superficial, Deep and Perforator Vein Incompetence

OBJECTIVE

The purpose of this study was to assess the effect of venous incompetence of the deep, superficial and perforator veins combined (i.e. multi-system incompetence) on the venous haemodynamics and clinical condition of limbs with chronic venous disease (CVD).

METHODS

One hundred and thirty two limbs (16-C(1); 30-C(2); 20-C(3); 25-C(4); 21-C(5); 20-C(6)) of 121 patients were studied. We excluded those with previous venous surgery/sclerotherapy, peripheral arterial disease, recent deep vein thrombosis (< or =6 months), or inability to comply with the tests. The CEAP clinical class was assessed. Duplex ultrasonography (ultrasound) enabled classification according to: the presence of superficial([S]) (+/- perforator([P])) or deep([D]) (+/-S, +/-P) reflux (>.5s); the number of incompetent venous systems (single-system([S/P/D]), dual-system([S+P/S+D/P+D]), or triple-system([S+P+D])), and the number of incompetent perforators([0/1/2/> or =3]). The amount of reflux (Venous Filling Index([VFI])); calf pump Ejection Fraction([EF]), and Residual Volume Fraction([RVF]) were studied with air-plethysmography.

RESULTS

VFI in limbs with triple-system incompetence (VFI median 6.68 [IQR: 4.7-9.7]ml/s) was higher than in limbs with dual-system incompetence (4.5 [2.1-7.4]ml/s), and VFI in the latter was higher than in limbs with single-system incompetence (1.3 [0.69-2.3]ml/s)(p<0.01 Kruskal-Wallis). Although EF changes were small, RVF in limbs with triple-incompetence (39 [30-51] %) was higher than in single-system incompetence (26 [16-33] %)(p<0.01 Mann-Whitney). Limbs with superficial (+/-P) incompetence had a lower VFI (p<0.01) and RVF (p<0.02) than limbs with deep (+/-S+/-P) incompetence, and limbs with > or =2 incompetent perforator veins had a higher VFI (p<0.04) than those without perforators. All limbs with single-system incompetence were C(1-3,) whereas 78% of those with triple-incompetence were C(4-6) (p<0.01). The number of incompetent systems increased with clinical class (p<0.01).

CONCLUSIONS

The frequency of incompetence of more than one venous system increased with the clinical severity of venous disease and was accompanied by a 5-fold increase in the amount of reflux and a 50% rise in the RVF. The number of incompetent perforators per limb increased with the amount of reflux. The number of incompetent venous systems (superficial, deep, perforator) and perforator veins can be assessed by duplex ultrasound giving an objective indication of the functional severity of venous disease. In this way duplex ultrasound could be used to grade venous function in clinical practice as an alternative to APG measures which are less widely available.

The utility of quantitative calf muscle near-infrared spectroscopy in the follow-up of acute deep vein thrombosis

BACKGROUND

To investigate patterns of venous insufficiency and changes in calf muscle deoxygenated hemoglobin (HHb) levels after an acute deep vein thrombosis (DVT).

METHODS

A total of 78 limbs with an acute DVT involving 156 anatomic segments were evaluated with duplex scanning and near-infrared spectroscopy (NIRS) at 1, 3, 6 and 12 months. Venous segments were examined whether they were occluded, partially recanalized, and totally recanalized, and the development of venous reflux was noted. The NIRS was used to measure calf muscle HHb levels. Calf venous blood filling index (HHbFI) was calculated on standing, then the calf venous ejection index (HHbEI), and the venous retention index (HHbRI) were obtained after exercise.

RESULTS

The segments investigated were the common femoral vein (CFV; 38 segments), femoral vein (FV; 37), popliteal vein (POPV; 44), and calf veins (CV; 37). At 1 year, thrombi had fully resolved in 67% of the segments, 27% remained partially recanalized, 6% were occluded. The venous occlusion was predominant in the FV (24%) at 1 year. On the contrary, rapid recanalization was obtained in CV than proximal veins at each examination (P < 0.01). Venous reflux was predominant in POPV (55%), followed by FV (19%), and no reflux was found in CV. At 1 year, the HHbFI in POPV reflux patients was significantly higher than those with resolution (0.19 +/- 0.14, 0.11 +/- 0.05 microm s, P = 0.009, respectively). Similarly, there was a significant difference in the HHbRI between the two groups (3.08 +/- 1.91, 1.42 +/- 1.56, P = 0.002, respectively). In patients with FV occlusion, the value of HHbRI was significantly higher than those with complete resolution (2.59 +/- 1.50, 1.42 +/- 1.56, P = 0.011, respectively).

CONCLUSIONS

The lower extremity venous segments show different proportions of occlusion, partial recanalization, and total recanalization. The CV shows more rapid recanalization than proximal veins. The NIRS-derived HHbFI and HHbRI could be promising parameters as the overall venous function in the follow-up of acute DVT. These findings might be very helpful for physician in detecting patients who require much longer follow-up studies.

Perforator vein incompetence in chronic venous disease: A multivariate regression analysis model

OBJECTIVES

In the presence of superficial and deep vein insufficiency the effects, if any, of concurrent incompetent perforator veins (IPVs) on clinical status are masked. On the basis of multivariate regression analysis, this study examines the significance of perforator vein incompetence across the clinical classes of CEAP (C-class CEAP ) in relation to the superficial and deep systems, and assesses the role of factors implicated in the presence and number of IPVs in chronic venous disease (CVD).

METHODS

The study included 525 limbs in 360 patients, ages 17 to 96 years, referred for investigation of CVD. The protocol entailed history taking, physical examination, and duplex scanning (reflux > 0.5 s), with emphasis on IPVs. Exclusion criteria included peripheral vascular disease, unrelated edema, severe chronic obstructive pulmonary disease, and recent (< 1 year) deep vein thrombosis (DVT).

RESULTS

Limbs were stratified as C 0 , 84; C 1 , 25; C 2 , 231; C 3 , 66; C 4 , 48; C 5 , 23; and C 6 , 48. C-class CEAP was separately regressed with age ( P < .001), sex ( P < .25), contralateral CVD ( P < .2), CVD recurrence ( P = .022), previous DVT ( P < .001), superficial vein reflux ( P < .001); deep vein reflux ( P < .001), perforator vein reflux ( P < .001), and number of IPVs ( P < .001). In an optimized multivariate regression analysis of C class CEAP with all significant variables combined, age ( P < .001), previous DVT ( P = .017), superficial vein reflux ( P < .001), deep vein reflux ( P < .001), and number of IPVs ( P = .008) emerged as predictors of CVD severity (CEAP), based on the equation C class CEAP = -0.2807 + 0.028013 Age + 0.58530 Previous DVT + 0.3450 Superficial vein reflux + 0.17781 Deep Reflux + 0.14537 IPVs ( R 2 = 37.4%; P < .001). Perforator incompetence was predicted by superficial vein reflux ( P < .001) and deep vein reflux ( P = .044), age ( P = .019), CVD recurrence ( P = .038), and sex ( P = .018), as follows: Perforator incompetence = -0.2532 + 0.006457 Age + 0.41366 Superficial reflux + 0.06766 Deep reflux + 0.2450 CVD recurrence - 0.21310 Sex ( R 2 = 33.3%; P < .001). Number of IPVs per limb was best associated with superficial reflux ( P < .001) and deep reflux ( P = .023), linked as IPVs = - 0.11789 + 0.41323 Superficial reflux + 0.07646 Deep reflux ( R 2 = 26.1%; P < .001).

CONCLUSION

Perforator incompetence proved to be a significant factor for determination of CVD severity according to C-class CEAP , withstanding the conspicuous confounding effects of the superficial and deep venous systems. Perforator incompetence was significantly linked to aging, superficial or deep vein incompetence, recurrence of superficial disease, and sex, whereas the IPV number, regardless of location, depended on the presence of superficial or deep venous reflux.

Investigation of chronic venous insufficiency: A consensus statement (France, March 5-9, 1997)

This consensus document provides an up-to-date account of the various methods available for the investigation of chronic venous insufficiency of the lower limbs (CVI), with an outline of their history, usefulness, and limitations. CVI is characterized by symptoms or signs produced by venous hypertension as a result of structural or functional abnormalities of veins. The most frequent causes of CVI are primary abnormalities of the venous wall and the valves and secondary changes due to previous venous thrombosis that can lead to reflux, obstruction, or both. Because the history and clinical examination will not always indicate the nature and extent of the underlying abnormality (anatomic extent, pathology, and cause), a number of diagnostic investigations have been developed that can elucidate whether there is calf muscle pump dysfunction and determine the anatomic extent and severity of obstruction or reflux. The difficulty in deciding which investigations to use and how to interpret the results has stimulated the development of this consensus document. The aim of this document was to provide an account of these tests, with an outline of their usefulness and limitations and indications of which patients should be subjected to the tests and when and of what clinical decisions can be made. This document was written primarily for the clinician who would like to learn the latest approaches to the investigation of patients with CVI and the new applications that have emerged from recent research, as well as for the novice who is embarking on venous research. Care has been taken to indicate which methods have entered the clinical arena and which are mainly used for research. The foundation for this consensus document was laid by the faculty at a meeting held under the auspices of the American Venous Forum, the Cardiovascular Disease Educational and Research Trust, the European Society of Vascular Surgery, the International Angiology Scientific Activity Congress Organization, the International Union of Angiology, and the Union Internationale de Phlebologie at the Abbaye des Vaux de Cernay, France, on March 5 to 9, 1997. Subsequent input by co-opted faculty members and revisions in 1998 and 1999 have ensured a document that provides an up-to-date account of the various methods available for the investigation of CVI.

Influence of popliteal vein thrombosis on subsequent ambulatory venous function measured by near-infrared spectroscopy

BACKGROUND

To determine the influence of the site affected by thrombi on the subsequent venous physiology, we examined patients with postthrombotic syndrome (PTS) with respect to ambulatory venous function using near-infrared spectroscopy (NIRS).

METHODS

Fifty-one limbs of 45 patients, for whom more than 1 year had passed since an acute episode of deep vein thrombosis, were studied. Seventeen limbs were asymptomatic, 27 had mild symptoms (edema only), and 7 showed severe symptoms (skin changes). The mean duration of PTS was 8.2 years. All of the patients underwent a treadmill walking test with simultaneous NIRS. Deoxygenated hemoglobin was continuously measured during exercise. The ambulatory venous retention index (AVRI) obtained from the serial deoxygenated hemoglobin changes was calculated in each patient. The location of thrombi at the onset of deep vein thrombosis was identified by venography.

RESULTS

The calculated AVRI was apparently related to the clinical symptoms of PTS. The limbs initially involved with popliteal vein thrombosis showed significantly higher AVRI values than those without popliteal vein thrombosis.

CONCLUSIONS

The clinical severity of PTS is correlated well with the degree of venous retention during exercise. Initial involvement of the popliteal vein is an important factor determining subsequent venous hemodynamics in patients with PTS.

The role of air plethysmography in the diagnosis of chronic venous insufficiency

PURPOSE

The role of air plethysmography (APG) in the diagnosis of venous disease is not well defined. We conducted this study to investigate the value of APG in the diagnosis of chronic venous insufficiency and to determine its correlation with the clinical severity of disease and the anatomic distribution of reflux.

METHODS

We studied 186 lower extremities with duplex scanning and venography and measured the venous volume, venous filling index (VFI), ejection fraction, and residual volume fraction with APG. Limbs were categorized according to the Society for Vascular Surgery and International Society for Cardiovascular Surgery classification of clinical severity of disease and according to the anatomic distribution of valvular incompetence.

RESULTS

Sixty-one limbs had no evidence of disease (class 0), 60 limbs had mild disease (classes 1, 2, and 3), and 65 limbs had severe disease (classes 4, 5, and 6). According to the results of duplex scanning and venography, there was no evidence of reflux in 56 limbs. Isolated superficial venous reflux occurred in 52 limbs, and perforator reflux, alone or in conjunction with superficial reflux, occurred in 30. Deep reflux, with or without superficial reflux, was found in 25 limbs. Deep and perforator reflux, with or without superficial reflux, was found in 19 limbs. The VFI had a sensitivity of 80% and 99% positive predictive value for any type of reflux. The VFI was significantly different between groups of limbs with different clinical severities of disease or different types of reflux. The incidence of deep or perforator reflux in limbs with a normal VFI value was 7%, and it was 82% in limbs with a VFI of more than 5. Among 86 limbs with VFI values not corrected with use of a thigh tourniquet, 28% did not have evidence of deep or perforator reflux, and among 15 limbs with VFI values corrected with the use of a tourniquet, 33% had perforator reflux, deep reflux, or both. All APG parameters had low positive predictive values for severe disease or ulceration. The ejection fraction and residual volume fraction did not influence the clinical severity of disease, did not discriminate between types of reflux, and in combination with the VFI did not improve the predictive value of APG.

CONCLUSIONS

The VFI measured by APG is an excellent predictor of venous reflux, provides an estimate of the clinical severity of disease, and at high levels predicts deep reflux, perforator reflux, or both. Correction of an abnormal VFI with a thigh tourniquet is an unreliable predictor of the absence of deep or perforator incompetence. The predictive value of APG for severe disease or ulceration is poor. The ejection fraction and residual volume fraction, individually or in combination with the VFI, add little to the diagnostic value of APG, and their routine performance may not be clinically justified.

A correlation of air plethysmography and color-flow-assisted duplex scanning in the quantification of chronic venous insufficiency

PURPOSE

Air plethysmography has been useful in assessing patients who have chronic venous insufficiency. Limb reflux times determined by color-flow-assisted duplex scanning have been shown to correlate with the severity of chronic venous insufficiency. The purpose of this study was to compare air plethysmographic measurements with reflux times obtained by color-flow-assisted duplex scanning in patients with chronic venous insufficiency.

METHODS

One hundred twenty-two limbs in 61 consecutive patients with various stages of chronic venous insufficiency were evaluated; air plethysmographic and color-flow-assisted duplex scans were performed at the same sitting. Fifty-nine of the patients had venous ulceration. Values obtained by air plethysmographic scans included venous filling index, ejection volume, residual volume, ejection fraction, and residual volume fraction. Color-flow-assisted duplex scan values included reflux times in the deep and superficial venous segments and total and mean limb reflux times.

RESULTS

Using the Pearson correlation, the venous filling index was found to correlate significantly with total limb venous reflux times, mean total limb reflux times, and venous reflux times in the deep venous system, as determined by color-flow-assisted duplex scans (p < 0.001).

CONCLUSIONS

Limb reflux time as determined by color-flow-assisted duplex scans correlated significantly with the air plethysmographic variable accepted as a measure of the severity of venous reflux, the venous filling index. This study confirms the validity of total limb reflux times in the quantification of chronic venous insufficiency.