What is peripheral artery disease (PAD)?

Peripheral artery disease, also called peripheral arterial disease (PAD), is a common circulatory problem in which narrowed arteries reduce blood flow to the limbs. When developing (PAD), the extremities — usually the legs — do not receive enough blood flow to keep up with demand.

Overview Published Clinical Data on FlowOx™

MoA/Circulatory effects:

Application of intermittent negative pressure on the lower extremity and its effect on macro- and microcirculation in the foot of healthy volunteers

Study conclusion:
The first study to describe the effects of INP on skin blood flow and arterial blood flow velocity. The first to compare different sequences of negative pressure oscillations on lower limb perfusion. This study found that application of frequent mild intermittent negative pressure (INP) of -40 mmHg in the foot in healthy volunteers induced rhythmical fluctuations in blood flow and increased both arterial blood flow velocity and skin blood flow.

Author: Sundby et. al. 2016. Download publication here!

The acute effects of different levels of intermittent negative pressure on peripheral circulation in patients with peripheral artery disease

Study conclusion:
INP of -40 and -60 mmHg applied in cycles of 10 sec of negative pressure and 7 sec of atmospheric pressure induced acute increase in arterial and skin blood flow.

Author: Hoel et. al. 2019. Download publication here!

The acute effects of lower limb intermittent negative pressure on foot macro- and microcirculation in patients with peripheral arterial disease

Study conclusion:
INP increases foot macro- and microcirculatory flow pulsatility. Application of INP resulted in increased mean arterial blood flow velocity.

Author: Sundby et. al. 2017. Download publication here!

Intermittent negative pressure applied to the lower limb increases foot macrocirculatory and microcirculatory blood flow pulsatility in people with spinal cord injury

Study conclusion:
INP induced an increase in arterial blood flow in the foot, followed by a decrease. This fluctuation was observed following the onset of negative pressure, without any significant changes in heart rate or mean arterial pressure.

This INP-induced increase in blood flow pulsatility during short oscillations of negative pressure may potentially promote tissue perfusion and ulcer healing in SCI people with ulcers in the lower limb.

Author: Sundby et. al. 2018. Download publication here!

Fluctuation in shear rate, with unaltered mean shear rate, improves brachial artery flow-mediated dilation in healthy, young men

Study conclusion:
INP induce fluctuations in blood flow and shear rate that improve endothelial function. This may represent a hemodynamic stimulus that improve vascular health.

Author: Holder et. al. 2019. Download publication here!

Impact on primary clinical endpoints:

A randomized controlled trial of treatment with intermittent negative pressure for intermittent claudication

Study conclusion:
Treatment with -40 mmHg INP for one hour twice daily for 12 weeks increased PWD compared with sham treatment. For patients with baseline PWD <200 m, treatment with -40 mmHg INP increased both PWD and MWD compared with sham treatment.

Author: Hoel et. al. 2020. Download publication here!

24 week follow up

Study conclusion:
Both PWD and MWD improved after treatment with –40 mmHg INP for one hour twice daily for 24 weeks compared with baseline. The main improvement in PWD occurred during the first 12 weeks of treatment, whereas the main improvement in MWD occurred between 12 and 24 weeks of treatment.

Author: Hoel et al. submitted 2021.

Impact on treatment of key symptoms:

The effects of intermittent negative pressure on the lower extremities’ peripheral circulation and wound healing in four patients with lower limb ischemia and hard‐to‐heal leg ulcers: a case report

Study conclusion:
In these cases, involving patients with hard-to-heal leg and foot ulcers, observed that INP therapy improved ulcer healing considerably. Foot perfusion improved after completion of 8 weeks of INP-therapy.

Author: Sundby et. al. 2016. Download publication here!

Intermittent mild negative pressure applied to the lower limb in patients with spinal cord injury and chronic lower limb ulcers: a crossover pilot study

Study conclusion:
INP can be used as a home-based treatment for patients with SCI and chronic lower limb ulcers. Its efficacy should be tested in an adequately sized, randomized clinical trial.

Author: Sundby et. al. 2018. Download publication here!

Health Economic Considerations:

Economic model to examine the cost-effectiveness of FlowOx home therapy compared to standard care in patients with peripheral artery disease

Study conclusion:
FlowOx™ therapy delivered as a single annual dose may be a cost-effective treatment for peripheral artery disease. It improved health outcomes and reduced treatment costs in this modeled cohort.

Author: Ezeofor et al., 2021. Download publication here!

Review Articles:

The FlowOx™ device for the treatment of peripheral artery disease_ current status and future prospect

Study conclusion:
FlowOx™ treatment increases walking capacity and may be a useful adjunct to standard care for patients with disabling intermittent claudication.

Observational data indicate a positive effect in selected patients with critical limb ischemia not amenable for revascularization. Treatment with FlowOx™ seems safe for patients with PAD and has few side effects. The system offers a new tool for the treatment of PAD, it enables patients to treat themselves at home.

Author: Hoel & Hisdal, 2021.

Patient and Clinician experiences and opinions of the use of a novel home use medical device in the treatment of peripheral vascular disease – a qualitative study

Study conclusion:
Patients and clinicians were positive about the device due to its ease of use. PAD patients experienced significantly more benefit, especially for ischemic ulceration than those with a chronic venous condition.

Clinicians placed value on the patient reported outcomes in the treatment decision-making process.

FlowOx™ demonstrates potential as a conservative therapy offering users a convenient, home use, self-care management solution for improving symptomatic PAD and quality of life (QoL).

Author: Sedgwick et al., 2021.

Pulsating negative pressure

Skin Blood Flow in a foot during FlowOx treatment
The video shows the live Doppler signal measuring blood flow velocity in a small artery in the foot (arteria dorsalis pedis). The recording is done on a patient with reduced peripheral circulation. Six seconds into the recording the negative pressure is applied for 10 second followed by a 7 second period of normal pressure. The sequence is repeated with the negative pressure starting again after 23 seconds and 40 seconds.

FlowOx™ is indicated for the treatment of

  • Peripheral arterial disease
  • Diabetic and non-diabetic arteriopathic foot and leg ulcers
  • Intermittent claudication and rest pain
  • Foot and lower leg ulcers of mixed aetiology associated with immobility such as paraplegia following spinal injury

Listen to Stine’s and Hans Thomas’ stories

Stine’s story with Flowox™
FlowOx™ first patient Hans Thomas