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Effects of calf muscle strengthening on venous hemodynamics and on quality of life in a patient with chronic venous insufficiency
(Portuguese PDF version)

Renata Cristina Magalhães Lima¹,Luciana Santiago¹, Regina Márcia Faria de Moura¹, Francisca Angélica Siqueira Filaretti¹,
Carmem Sílvia Acyprestes de Souza¹, Solange Seguro Meyge Evangelista^2, Raquel Rodrigues Britto³

1. Physical therapist, Hospital das Clínicas, Universidade Federal de Minas Gerais.
2. Physician, Hospital das Clínicas, Universidade Federal de Minas Gerais. Specialized in Angiology, Brazilian Society of Angiology and Vascular Surgery.
3. PhD in Physiology, Hospital das Clínicas, Universidade Federal de Minas Gerais.

Correspondence:
Dr. Raquel Rodrigues Britto
Departamento de Fisioterapia
Av. Antônio Carlos, 6627 - 3º andar
CEP 31270-901 - Belo Horizonte - MG
Tel.: +55 31 3499 4782 Fax: +55 31 3499 4781
E-mail: rbrito@eef.ufmg.br

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ABSTRACT

A 41-year-old volunteer diagnosed with chronic venous insufficiency 21 years ago was classified as class 4 by the CEAP Clinical Classification and as class 2 by the Venous Clinical Severity Score. The following variables were assessed before and after the training program: strength of the calf muscles in both legs; calf pump function, determined by air plethysmography; and quality of life, determined by Nottingham Health Profile scores. The protocol consisted of 30 sessions, with emphasis on the left lower extremity. Strength increases of 198.4% for the left and of 28.3% for the right calf muscles were observed, associated with a reduction of the functional venous volume on the right (2.2%) and left (3.4%) limbs. There was reduction of the residual volume fraction (2.7 and 38.5% for the right and left limbs, respectively); and an increase in ejection fraction of 17.8% on the right limb and of 45.5% on the left limb. However, there was no change in venous filling index. Quality of life improved 66.7% on the Nottingham Health Profile. We concluded that strengthening of the calf muscles may improve venous hemodynamics and quality of life in patients with chronic venous insufficiency.

Key words: venous insufficiency, physical therapy, quality of life, plethysmography
Palavras-chave: insuficiência venosa, fisioterapia, qualidade de vida, pletismografia.

J Vasc Br 2002;1(3):219-26

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INTRODUCTION

Chronic venous insufficiency (CVI) is a dysfunction of the venous system caused by valve incompetence associated or not with obstruction of venous flow. It may affect the superficial venous system, the deep venous system, or both. In addition, venous dysfunction may result from a congenital or acquired disorder.¹

The incidence of CVI is higher after the third decade of life, affecting fully mature individuals, in a moment in which their work capacity is greater.² An epidemiological study conducted in some countries showed the incidence of at least one form of venous disease in over 50% of women and 30% of men.³ Ulcer, a late complication of CVI, has been found in 0.06 to 0.2% of the population in countries such as France, Italy, Belgium, Denmark and Canada, with an incidence rate of 3.5/1,000/year in individuals older than 45 years.³,⁴ The ulcers observed in the lower extremities are caused by venous dysfunction in 60 to 80% of the cases.³ Combined with this high incidence is the high cost of treatment. In the United States, this cost is estimated between 1.9 and 2.5 billion dollars a year. Ulceration affects productivity at work, and is a cause of disability retirement; in addition, it restricts leisure and daily activities.⁴,⁵ For many patients, venous disease means pain, loss of functional mobility and deterioration of the quality of life.³,^6-8

In Brazil, the socioeconomic importance of CVI has been considered by the government only in the last few years, which has led to a growing interest in the scientific and clinical knowledge of issues related to this disease.²

Traditional measurements of morbidity and mortality are clinically weak and do not show the benefits of health care in the intervention of CVI with sufficient sensitivity. An early assessment of the issues related to CVI is crucial so that costly treatments and the development of severe forms of the disease can be prevented.⁹ Diagnostic techniques have improved considerably; however the prevention and treatment of the disease have to be further investigated.⁷,⁸

CVI and its complications are almost always related to an inadequate calf pump. This pump, when in perfect operation, compresses the deep calf veins - anterior tibial and fibular veins- during contraction. The distal valve of the deep vein and the valves of perforating veins close and the blood is ejected towards the heart. During calf relaxation, a huge reduction of pressure occurs in the deep veins, and negative pressures may build up; the proximal valve of the deep axis is then closed. This way, the venous pressure of the superficial network is higher than that of the deep axes, and the blood is deeply aspirated through the perforating veins.¹⁰ This "peripheral heart," which has an aspirating and compressive action may reduce the hydrostatic venous pressure of an individual from100 mmHg to values close to 0-30 mmHg during ambulation (ambulatory venous pressure - AVP).⁷,¹¹,¹²

Any process that hinders the proper functioning of calf muscles and of the valve tract interferes with venous circulation.^13-15 The dysfunction of the calf pump, associated or not with valve dysfunction is responsible for venous hypertension, which causes an excessive deposition of fluid and fibrinogen in the subcutaneous tissue, resulting in edema, lipodermatosclerosis and, finally, ulceration.⁵,⁷,¹⁵ In cases of reflow, for example, at the first signs and symptoms, the "peripheral heart" tries to offset the overload of volume of insufficient veins, ejecting a greater volume of blood. With the deterioration of reflow, the pump becomes unable to carry out the cyclic reduction from 100 mmHg to 0-30 mmHg. Therefore, chronic permanent venous hypertension establishes itself, triggering off the signs and symptoms of CVI. This elevation in AVP is predictive of ulceration, as well as the reduction of ejection fraction (EF) and the increase in the venous filling index (VFI) and in the residual volume fraction (RVF).¹¹

The improvement of the calf muscle function helps to solve venous disorders.⁵,¹³ An adequate calf pump could prevent later complications, such as ulcers, and minimize the signs and symptoms of CVI. Some studies have investigated the influence of calf strengthening in patients with CVI,⁶,¹⁶ and have obtained good results.

The aim of this study was to assess the effects of calf muscle strengthening on venous hemodynamics and quality of life in CVI patients.

MATERIALS AND METHODS

This study consisted of an experimental investigation of a single case and was conducted at Borges da Costa Outpatient Clinic of Hospital das Clínicas of Universidade Federal de Minas Gerais (UFMG). The study was approved by the local Ethics and Research Committee.

The inclusion criteria were the following: participants should have CVI, categorized as classes 3, 4 or 5 by the CEAP Clinical Classification1 or as classes 1 or 2 by the Venous Clinical Severity Score,¹⁷ diagnosed by an angiologist. They should also be able to walk during 20 minutes and do physical activities for 45 minutes with rest intervals; have a medical statement that dismisses them from any other duties so that they can perform the proposed physical activities; have an EF lower than 60% in at least one of the lower limbs; have no restriction as to ankle movement; be receiving no treatment for CVI; be free of decompensated heart failure and sudden increase of arterial pressure during the muscle strength test; have no neuropathy on the lower limbs; have no intermittent claudication; and have signed the consent form for participation in the study.

A 41-year-old volunteer, civil servant, recruited from the community was assessed. She complained of weight and pain in the left lower limb, and had been diagnosed with CVI 21 years ago, classified as class 4 (trophic skin changes) according to the CEAP Clinical Classification1 or class 2 (moderate) according to the Venous Clinical Severity Score,17 submitted to partial saphenectomy of the left great saphenous vein and sclerotherapy, with presence of bilateral varicosities and EF of 39.1% on the left lower limb. Even though the patient did not show symptoms on the right lower limb, EF was 46.6%. The venous duplex scan of the left lower limb, performed on May 25, 2000, revealed no signs of thrombosis in the deep vein system, incompetence of the small saphenous vein and presence of reflow.

Variables assessed

All variables were assessed before and after the training program, and each test was carried out by the same examiner.

Strength of the calf muscle

The strength of the calf muscle was measured by a hand-held dynamometer, according to Bohannon.¹⁸ The Nicholas Manual Muscle Tester: Model 01160® was used.

To carry out the test, the patient was placed in the prone position with her hips and knees stretched and her feet dangling down. The plunger of the device was positioned at the plantar surface over the metatarsophalangeal joint at the height of the head of the first metatarsus and the patient was asked to perform a plantar flexion against the examiner's resistance (the examiner offered resistance against the movement). Three measurements were performed in each limb, and the mean was then calculated. The device gives the measurements in kilogram force (kgf), which were turned into newton-meter (Nm) by the formula: kgf x 9.81 x distance from the head of the 5th metatarsus to the lateral malleolus.

Calf muscle pump function and venous reflow

Calf muscle pump function and venous reflow were assessed by air plethysmography (APG). An SDV 3.000 device, brand Angiotec® was used.

APG is a noninvasive method described in the 1980s by Christopoulos et al.¹⁵ that quantifies the variation of leg volume as a result of venous filling or emptying due to a change in posture or exercise. The air plethysmograph uses a polyurethane cuff with 35 cm in length and a capacity of 5 l, which envelops the whole extension of the leg, from the knee down to the ankle. The cuff is automatically inflated up to 6 mmHg (a pressure that allows good contact with the skin and minimal occlusion of the veins) and is hooked up with a transducer, an amplifier and a graphic recorder. The exam is interpreted on a graph that registers the volume at the ordinate and the time at the abscissa (Figure 1). APG is performed with the patient in the supine position, with the leg elevated at 45 with external rotation, the knee slightly flexed and the foot propped up. The cuff is inflated, the baseline value is obtained and then the patient is asked to get up with a little help from the examiner and to stand on the unassessed limb by using a walker as hand support. The increase of leg volume is observed until it reaches a plateau. The difference between the initial volume and the plateau volume represents the functional venous volume (VV). The VFI is defined as the ratio between 90% of VV and the time necessary to reach 90% of the filling (VRT 90) (VFI = 90% VV / VRT 90). After that, the patient was asked to place all her weight on both lower limbs, perform a plantar flexion and return to the previous position. The drop observed on the graph corresponds to the ejected volume (EV), which results from the contraction of the calf muscles. A new plateau was reached and the patient was asked to perform 10 plantar flexions, at the speed of one movement per second, always returning to the previous position. After the test, the patient returned to the initial supine position. The residual volume (RV) was calculated from the initial baseline value in relation to the remaining volume at the end of the movements. EF was calculated by EF = (EV / VV) x 100, and RVF by RVF = (RV / VV) x 100.¹¹,¹⁵,¹⁹

Figure 1 - Graph obtained from air plethysmography. Ordinate showing blood volume in milliliters (ml) and abscissa showing time in seconds (s).

Quality of life

The quality of life (QoL) was evaluated through the Nottingham Health Profile (NHP).²⁰ This questionnaire offers measurements of an individual's perception in relation to his/her physical, social and emotional well-being and has a reliability rate of 0.75-0.88. The questionnaire consists of 38 yes/no questions based on the classification of incapacity described by the World Health Organization, distributed into six domains: energy level, pain, emotional reactions, sleep, social isolation and physical abilities (three, eight, nine, five, five, and eight questions, respectively). Each positive answer gets one point; the lower the score, the better the QoL.

Training program

The protocol consisted of 30 sessions three times a week, with special emphasis on the left lower limb. Before and after each session, arterial blood pressure and heart rate were measured. Exercises such as stretching, strengthening of the left lower limb, treadmill walking, and relaxation were performed.

Stretching exercises

Static stretching was used and the muscles were stretched for 20 seconds in four repetitions, as described by Taylor et al.²¹ The groups of muscles that were stretched were the following: ischiotibial muscles (once) and calf muscle (twice, the last time being performed after walking on the treadmill).

Strengthening

The strengthening of the calf muscle included the following exercises:

1 - plantar flexion of the ankle at an orthostatic position, with support for one foot or for both feet, on the floor or on a step;

2 - plantar flexion with the patient sitting with her knee extended and with resistance to plantar flexion of the left and right lower limbs, one at a time, by means of a latex tube;

3 - plantar flexion with the patient in a prone position, with the knee flexed at 90° and with manual resistance at the plantar face of the left and right feet.

The number of repetitions and series performed by the patient were the following: three series with 10 repetitions in each exercise for the left lower limb, with a later increase to five series; and one series with 10 repetitions throughout the treatment for the right lower limb.

Walking

The patient walked on a treadmill (VITAMASTER PRO®, model 8713 SA) at a maximum and self-selected speed of 3.4 km/h for 20 minutes. Aside from functional training, the purpose of walking on the treadmill was to benefit from the calf muscle mass for venous return by means of striding steps and to obtain a greater mobilization of the metatarsophalangeal joints.

Relaxation

After all the exercises, the patient was asked to lie down on a mat with her lower limbs elevated over a 29-cm foam prop for 5 minutes.

Analysis of the variables

Use of descriptive analysis expressed in % and visual data analysis.

RESULTS

The results of the training program to which the patient was submitted during 30 sessions are shown in Table 1. Calf strengthening resulted in an increase of muscle strength of 198.42% in the left calf muscle and of 28.26% on the right side (Figure 2).

Table 1 - Results of the variables measured before and after intervention: calf muscle strength, venous filling index (VFI), functional venous volume (VV), ejection fraction (EF), residual volume fraction (RVF) and Nottingham Health Profile (NHP)

Variables	Before		After		Δ %
	D	E	D	E	D	E
Calf muscle strength (Nm)	9.06	3.80	11.62	11.34	28.26	198.42
VFI (ml/s)	0.91	2.93	1.07	2.82	17.6	3.7
VV (ml)	111.9	168.5	109.4	162.8	2.2	3.4
EF (%)	46.6	39.1	54.9	56.9	17.8	45.5
RVF (%)	29.1	42.3	28.3	26.0	2.7	38.5
NHP	12		4		66.7

Figure 2 - Measurements of calf muscle strength before and after the training program on right lower limb (RLL) and left lower limb (LLL).

The VV decreased by 2.2% on the right lower limb and by 3.4% on the left lower limb, whereas the RVF decreased by 2.7% and 38.5% on the right and left lower limbs, respectively. The EF increased by 17.8% on the right lower limb and by 45.5% on the left lower limb (Figure. 3). The VFI did not show any important alteration according to the literature, which considers values lower than 2 ml/s to be normal¹¹. The VFI of the left lower limb was 2.93 ml/s, with a value greater than 2 ml/s (2.82 ml/s) after the training program. The VFI of the right lower limb was normal (before: 0.91 ml/s; after: 1.07 ml/s). The QoL was also improved with a reduction of 66.7% in the NHP total score. As to the energy level and social isolation, no alteration was observed (score = 0 before and after; 0% variation), whereas the score for sleep and emotional reactions changed from 1 to 0 in both cases (a 20 and 11.1% variation, respectively). The score for physical ability changed from 3 to1 (25% variation), and the one for pain, from 7 to 3 (75% variation) (Figure 4).

Figure 3 - Measurements of ejection fraction (EF) before and after training of right lower limb (RLL) and left lower limb (LLL).

Figure 4 - Result of parameters assessed by the measurement of quality of life (QoL) by means of the Nottingham Health Profile (NHP), total score and in each one of the six domains.

DISCUSSION

According to Arnoldi, apud Alimi et al.¹² the normal functioning of the calf muscle pump occurs when the venous flow of the lower limb equals the arterial flow during exercise, without dilation of the lower limb veins, thus maintaining a low pressure in this region.¹² The proper function of the pump plays a crucial role in the rehabilitation of CVI patients. The pump partially compensates for venous hypertension; and the effects of venous reflow are more complicated with an inadequate pump. It has a definite role in venous hemodynamics due to its high capacitance, anatomical positioning on the lower limb, where the venous pressure is highest, and also due to its power to build up high pressures.⁶ The dysfunction of the pump deteriorates the clinical status of the disease.

The patient had an EF < 60% in both lower limbs, which means dysfunction of the calf muscle pump.⁶ However, emphasis was given to the left lower limb since the symptoms were present on this limb only, which explains the higher increase of muscle strength in the left rather than in the right calf. Initially, the muscle strength of the right calf was almost two times that of the left calf, and at the end of 30 sessions, the strengths almost evened out. In a prospective controlled study carried out by Kan & Delis,⁶ in which 10 of 21 patients with CVI and ulcer were submitted to a training program for calf strengthening for seven days in a row with an overload of 4 kg, a 135% improvement in performance was observed . A failure of the present study was not to measure the overload during muscle strengthening. In spite of this, an improvement of 198.42% in muscle strength was observed on the left lower limb, against 28.26% on the right lower limb.

Taheri et al.,²² through the biopsies of the gastrocnemius of patients with CVI and venous hypertension, observed three types of morphological lesions that affect the muscle tissue: atrophy of fibers type II, denervation, and myopathic disorders (noted due to the denervation of fibers, inflammation, and necrosis with perivascular accumulation of lymphocytes). The precise cause of atrophy in fibers type II in patients with CVI still remains unclear; however, it is possible to say, at least in part, that it is related to the nonuse of calf muscles due to pain or edema, which ends up restricting movements.

All patients with chronic venous disease should have a complete assessment of their venous hemodynamics before and after any treatment, so that the benefits of such treatment can be determined;¹³ The hemodynamics of the calf muscle pump has been currently studied by means of APG, EF and RVF.⁶,¹¹,¹⁵¹⁸,²³,²⁴ In the study conducted by Kan & Delis.⁶ a significant difference in EF and RVF was detected in the treated group and in EF between the treated and control groups; whereas parameters VV and VFI did not show any difference (p > 0.05). These results are consistent with the findings of the present study, in which an increase in EF was observed on both lower limbs and a reduction of RVF was noted on the left lower limb. The EF of the right lower limb increased from 46.6 to 54.9%, and that of the left lower limb, from 39.1 to 56.9%. According to Evangelista,¹¹ an EF< 40% (as observed in our study on the left lower limb before the treatment) may determine ulceration in the lower limbs with minimal reflow. The patient showed reduction of RVF on the left lower limb from 42.3 to 26% on the left lower limb. According to Evangelista,¹¹ the incidence of ulceration was zero, since RVF values < 30% are correlated with zero incidence of ulceration. RVF offers a reliable estimate of AVP:¹¹,¹³ however, this correlation is more significant for patients with venous obstruction than for those without it.¹³

According to the data obtained by Nicolaides & Summer (1991), apud Evangelista,¹¹ the incidence of ulceration is related to EF and VFI. An EF < 40% and a VFI between 5 and 2 ml/s correspond to an ulceration rate of 32%, while an EF between 40 and 60% and a VFI with the same values correspond to an ulceration rate of 2%.¹¹

Based on these data, the patient's incidence of ulceration was reduced from 32 to 2% on the left lower limb in the present study.

A study conducted by Welkie et al.¹³ with 274 limbs of 149 patients with a different classification of chronic venous disease revealed that from the onset of considerable edema and hyperpigmentation of the skin, ulceration develops without additional deterioration of the hemodynamics. Therefore, a calf muscle pump is necessary for the prevention of such complications.

The present study showed a variation lower than 4% in relation to VV and VFI values, except for the right lower limb, which demonstrated a VFI increase of 17.58% (Table 1). Kan and Delis⁶ already expected these values not to be influenced by muscle strengthening. VV is related to venous capacitance, and VFI is an indirect measurement of reflow, associated with the level of valve dysfunction.

CVI interferes with the QoL of patients by limiting their daily activities.³,^6-8 The present study showed improvement of pain, physical ability, sleep and emotional reactions, among which the first three accounted for the highest variation in the total score obtained through the questionnaire (75%, 25% and 20%, respectively). The NHP was sensitive in detecting alterations in the patient's QoL. As the incidence of ulceration of the patient reduced considerably, the QoL is expected to be better than that at the beginning while she can benefit from the gain of muscle strength obtained with the application of the training program. On the other hand, it is not possible to infer the long-term benefits obtained after the training program.

CONCLUSION

The use of physical therapy in CVI patients is quite recent and therefore there is scarce research in this area. The present study is not conclusive, since it includes a single case; however, it shows some signs that calf muscle strengthening can improve venous hemodynamics and the quality of life of patients. Studies with a larger sample are necessary to confirm the results obtained herein.

ACKNOWLEDGMENTS

Thanks to Borges da Costa Outpatient Clinic, which kindly gave us permission to use its premises and VITAMASTER PRO® treadmill, model 8713 SA. Also thanks to professor Luci Fuscaldi Teixeira-Salmela, who lent us the Nicholas Manual Muscle Tester, model 01160®.

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