Exercise as it relates to Disease/How beneficial is physical conditioning of calf musculature in people with Chronic Venous Insufficiency

This is a critique of the following paper (http://www.jvascsurg.org/article/S0741-5214(03)01412-5/fulltext), completed by student u3102066 for the unit 'Health, Disease and Exercise'.

Research background

Chronic Venous Insufficiency Risk Factors/Treatment Options

Chronic Venous Insufficiency (CVI) indicates functional abnormality of the venous system and is primarily caused by the following pathologies related to the calf muscle pump:

• Pooling of blood in the lower limb due to ineffectiveness of one-way valves
• Poor muscular activity leading to insufficient vein compression
• Obstruction in the veins, preventing blood flow.

Risk factors:

• Increases in age
• Prolonged immobility
• Previous venous insufficiency/ulceration
• Recent cardiac, pulmonary or orthopaedic surgery

Due to the age factor, the ageing population may lead to increased prevalence of CVI and a greater need for cost-effective treatment options. For cases of severe CVI, treatment options are limited. Surgical interventions have historically been significantly effective in treating CVI, although in many cases surgery is not considered. Without surgery, many individuals remain chronically incapacitated and experience decreased functional mobility and well-being.

Calf Muscle Pump

• Muscular contractions compress and squeeze blood back towards the heart, influencing venous return.
• Calf muscle pump failure, diminished musculoskeletal function and reduced ankle range of motion (ROM) are closely associated with progressive severity of CVI.
• The current study aims to investigate whether improving calf muscle pump function, ankle mobility and strength would correlate to a venous hemodynamic improvement and greater functional mobility.

Current Study

Research Background

Research institutes involved:

• University of Medicine and Dentistry (New Jersey)
• Veterans Affairs New Jersey Health Care System
• Kessler Medical Rehabilitation Research and Education Corp.

Research Locations:

• Vascular laboratory or clinic
• Physical therapy department
• The patient's home

Findings were presented at the annual meeting of the Society for Vascular Surgery, and later published in the peer reviewed Journal of Vascular Surgery.

Research Design

The current study was a randomised control trial (RCT). RCTs are effective for determining a cause-effect relationship between an intervention and an outcome. Participants were randomly allocated to a group (control or intervention), and the study was unblinded (all participants knew who was in which group).

Table 1: Treatment setup for unblinded groups

Treatment Group	Sample Size (n)	Treatment Type
Control	13	Compression stockings for 6 months
Physical Therapy	17	Three months supervised therapy followed by three months unsupervised therapy. Therapy included uphill treadmill walking, lower limb and trunk stretching/strengthening and resistance training

Advantages

• Determines cause-effect relationships
• Randomisation reduces bias
• Specific and valid population was used

Disadvantages

• Unblinded groups increase bias
• High exclusion rate, reducing sample size
• Elderly population (mean age=70)

Research Details

30 participants were recruited from an outpatients veteran clinic from a possible 77 subjects. The inclusion criteria for the study was:

1. Presence of skin changes/ulceration
2. Objective evidence of CVI– as determined through Venous Clinical Severity Scores (VCSS).

Hemodynamic and musculoskeletal variables were measured at 0 and 6 months for the control group, and at 0, 3 and 6 months for the physical therapy group. The hemodynamic variables were measured using air plethysmography (APG), which uses pressure cuffs to establish venous flow. Musculoskeletal variables were measured using an isokinetic dynamometer.

Table 2: Hemodynamic Variables

Variable	Measures	Meaning
Venous Filling Index (VFI)	Volume of blood in veins/second of refill time (ml)	High VFI is associated with CVI
Ejection Fraction (EF)	Volume of blood ejected after a single toe raise.	Measure of the calf muscle pump function
Residual Volume Fraction (RVF)	Volume of blood remaining after 10 toe raises	High RVF = Poor blood flow/drainage
Outflow Fraction (OF)	Presence/amount of obstruction in the veins	-OF < 38% = venous obstruction -OF < 28% = poor blood flow.

Table 3: Musculoskeletal Variables

Variable	Meaning
Peak Torque	The highest amount of tension a muscle can produce at a specific range of motion
Peak Torque/Body Weight Unit	Peak torque normalised for body weight
Maximal Repetition Work	Maximal work in a set
Total Work	Torque maintained through full ROM
Average Power	Total average work intensity
Maximal ROM	Total ROM in the ankle joint

• Research indicates APG is effective in diagnosing severity of disease and venous reflux, and therefore was reliable and valid
• Isokinetic Dynamometre proven to be reliable and valid
• Variability is common in measures of human performance, tests were completed twice which improved the reliability.
• Comorbidities including obesity, arthritis, angina, hypertension, asthma and diabetes, were prevalent in a high number of participants. These may have secondarily affected venous function. The control group contained a larger number of comorbidities, although not significant.

Results Summary

Main Findings:

• Physical therapy had an effect on EF and RVF in both groups.
• In the therapy group:

- Calf muscle pump function increased (EF)

- Pooling of blood in the calf was decreased (RVF)

- Mean peak torque per unit of body weight increased significantly

Other Findings:

• No other musculoskeletal or hemodynamic differences were observed
• No changes in VCSS scores for both groups, meaning CVI severity was not reduced.
• No differences between groups in QOL or functional mobility questionnaires

Discussion

The researchers concluded that:

• Structured exercise programs can improve calf muscle pump function and hemodynamic performance.
• Benefits can be sustained for at least three months after supervised exercise programs are completed.
• Unsupervised exercise programs are beneficial.
• Improvement in calf muscle pump function does not necessarily correlate to improved functional mobility and quality of life

Conclusions and Implications

• The study indicates that structured exercise programs are a viable option when surgery is not available.
• Limitations of the study included:

- small sample size

- elderly demographic

- high exclusion rate

- single-faceted study

• Further research could focus on different exercise modalities, intensities and durations in order to optimise health improvements.
• Overall, researchers used effective scientific methods and instruments to conduct a study that has provided valuable information and useful recommendations for future studies.

Further information/resources

For Further information regarding CVI read the following:

• Methods of investigating CVI:

http://circ.ahajournals.org/content/102/20/e126.short

• Exercise after acute CVI or deep vein thrombosis:

http://www.sciencedirect.com/science/article/pii/S0741521405012310

• Exercise to prevent travel related deep vein thrombosis:

http://www.ncbi.nlm.nih.gov/pubmed/17723128