Intermittent Negative Pressure to Improve Blood Flow in Patients With Peripheral Artery Disease: Effects After Long-term Treatment

Overview

Studies have shown that intermittent negative pressure (INP) can induce short-term increase in blood flow in the extremity in patients with peripheral artery disease (PAD). Case reports also have indicated that INP treatment has beneficial hemodynamic and clinical effects in patients with lower limb ischemia and hard to heal leg ulcers. However, the clinical and physiological effects of long-term INP treatment are not well documented and needs further investigation.

A double-blinded randomized sham-controlled trial. Otivio AS is the developer of FlowOx, a noninvasive CE marked device to increase blood flow to the lower extremity. The device acts as a pressure chamber sealed around the patient's lower leg, applying pulses of intermittent negative pressure and atmospheric pressure. The pressure pulses are generated by a control unit, alternating between removing air from- and venting the pressure chamber. Preliminary tests indicate a significant increase in blood flow to the extremity during INP treatment at -40 mmHg, but a similar increase in blood flow was not detected during treatment INP treatment at -10 mmHg. Hence, treatment with -10 mmHg, may serve as a sham intervention, when evaluating the clinical and physiological effects of long-term INP treatment. All patients will receive best medical treatment including advice for smoking cessation, dietary advice, and advice for physical exercise, and pharmacological treatment with statins and platelet inhibitors. Patients will be randomized into two groups, one group receiving INP treatment with a pressure of -10 mmHg, the other group receiving INP treatment with a pressure of -40 mmHg. Treatment will be conducted by the patient him/herself at home, one hour in the morning and one hour in the evening for 12 weeks. Pain-free- and maximal walking distance, ankle-brachial index, arterial blood flow during application of INP, maximal blood flow, and biomarkers of inflammation and endothelial dysfunction will be registered at baseline and after 12 weeks to evaluate the effects of long-term INP treatment.