title: The calf muscle pump revisited.
abstract: BACKGROUND
  Chronic venous disease (CVD) defines the spectrum of manifestations of venous disease that originate as a result of ambulatory venous hypertension. Thus far, the role of the calf muscle pump in the development and potentiation of CVD has been overlooked and understated in the clinical setting, with much greater emphasis placed on reflux and obstruction. The aim of this review is to explore the level of significance that calf muscle pump function or dysfunction bears on the development and potentiation of CVD.
  
  
  METHODS
  EMBASE and MEDLINE databases were searched with keywords "calf" AND "muscle" AND "pump" AND "venous" AND "insufficiency" AND ("lower limb*" OR "leg*"), screened for cross-sectional and longitudinal studies relating to chronic venous insufficiency, highlighting the role of the calf muscle pump in CVD and the extent to which the calf muscle pump is impaired in these cases. This resulted in the inclusion of 10 studies.
  
  
  RESULTS
  Compared with healthy subjects, patients with CVD have a reduced ejection fraction (15.9%; P < .001) and an increased venous filling index (4.66 mL/s; P < .001), indicating impairment in calf muscle pump ejection ability as well as poor venous competence. Calf muscle pump dysfunction is present in 55% of patients with CVD in the literature, but this did not reach significance on meta-analysis. Isotonic exercise programs in patients with active and healed ulcers have been shown to increase calf muscle pump function but not venous competence.
  
  
  CONCLUSIONS
  Calf muscle pump failure is a therapeutic target in the treatment of CVD. Evidence suggests that isotonic exercise treatment may be an effective method of increasing the hemodynamic performance of the calf muscle pump.
  
  
  CONCLUSIONS
  This review emphasizes the requirement for more attention to be placed on the treatment of calf muscle pump failure in cases of CVD by use of exercise treatment programs or other methods, which may be of clinical importance in managing symptomatic disease. To establish this in routine clinical practice, these results would need to be replicated in appropriate clinical trials. It would also be logical to look at other modifiable muscle pumps, such as the thigh and foot, and to explore the potential benefit of electrical devices acting on the leg (eg, electrical muscular or neuromuscular stimulation), especially for those patients in whom exercise capacity is limited.
authors.affiliation: Academic Section of Vascular Surgery, Imperial College London, London, United Kingdom.
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Williams
authors.affiliation: Imperial College Medical School, London, United Kingdom.
authors.forename: Olufemi
authors.initials: O
authors.lastname: Ayekoloye
authors.affiliation: Academic Section of Vascular Surgery, Imperial College London, London, United Kingdom.
authors.forename: Hayley M
authors.initials: HM
authors.lastname: Moore
authors.affiliation: Academic Section of Vascular Surgery, Imperial College London, London, United Kingdom. Electronic address: a.h.davies@imperial.ac.uk.
authors.forename: Alun H
authors.initials: AH
authors.lastname: Davies