The IMPACT PAD Study (IMPACT PAD)

A Safety and Feasibility Study of Intraprocedural Physiology Measurements During Peripheral Endovascular Treatment

Endovascular treatment for peripheral arterial disease is commonly performed for claudication or critical limb threatening ischaemia (ischaemic rest pain, foot ulcer or gangrene). Disease is generally identified using Ankle Brachial Pressure Index or Toe Brachial Pressure Index and then lesions delineated using Doppler ultrasound or CT angiography. Clinical severity is staged using absolute walking distance (metres) in claudicants or the Society for Vascular Surgery wIfI (wound, ischaemia, foot infection) score in critical limb threatening ischaemia patients. Intra-procedural lesion assessment and quality control is currently performed anatomically using angiography alone, with a few centres using pullback pressures across a lesion to give supplementary trans-lesional gradients or intravascular ultrasound (IVUS) to give pre and post intervention diameter and vessel area measurements. No direct or quantitative assessment of flow, or pressure normalisation across lesions is currently performed during interventions to improve blood flow to the leg.

The aim of IMPACT PAD is to examine the safety and feasibility of intraprocedural flow, pressure and resistance rate changes to help predict the success of a peripheral endovascular intervention.

Inclusion Criteria: 18 years of age Peripheral arterial stenosis scheduled for endovascular treatment Exclusion Criteria: < 18 year of age Unable to give informed consent Estimated GFR ≤30 mL/min Dialysis dependent Unable to receive antiplatelets or periprocedural anticoagulation Pregnancy or breastfeeding Contraindication to adenosine (severe asthma or COPD) WIfI ulcer score <2 (no exposed bone) WIfI infection score <2 (skin and subcutaneous tissues only) WIfI gangrene score <3 (limited to digits) COVID-19 positive NYHA IV heart failure Contra-indication to adenosine including arrhythmia, asthma or allergy