PAD Screening Study

Summary

Peripheral arterial disease (PAD) due to atherosclerotic narrowing of arteries of the lower limb is common and associated with increased cardiovascular mortality and morbidity. The prevalence of PAD increases with age affecting approximately 10% of population age \>60 years and nearly 50% age \>85 years. However, the awareness of PAD is poor with less than 5% of patients with PAD aware of their condition; and the condition is often underdiagnosed and undertreated. Clinical diagnosis of PAD can be difficult because up to 50% of patients do not complain of overt symptoms such as intermittent claudication (IC) and critical limb ischemia (CLI). The prognosis of patients with PAD is not benign irrespective of symptoms. Atherosclerosis is a systemic disease where 30% to 50% of patients with PAD have concomitant coronary artery disease (CAD) and cerebrovascular disease (CVD) and they share common risk factors including diabetes mellitus, hyperlipidemia and hypertension. In the multi-national REACH registry, 1 in 5 patients with PAD experienced CV death, MI, stroke, or hospitalization within 1 year which is even higher than patients with CAD or CVD. Screening may increase early detection of PAD and provide opportunity to identify concomitant CV diseases and/or risk factors, earlier treatment and hence reduction. in adverse CV events. However, there is lack of an accurate and cost-effective assessment tool for PAD screening. Resting Ankle-Brachial Index (ABI) which measures the difference in blood pressure between the arm and the ankle as a ratio is the most widely used method to diagnose PAD. An ABI \<0.9 is diagnostic of obstructive lower limb PAD with sensitivity of 97% and a specificity of 80-100%. ABI performed with exercise (i.e. exercise ABI) has been shown to increase the diagnostic yield of resting ABI when the clinical suspicion for PAD is high and the resting ABI is normal. Exercise is usually performed with a treadmill or active pedal plantar-flexion (APP) when patient is unable to walk on the treadmill. Resting and exercise ABI measurement can be performed in an outpatient setting but is time consuming, and requires technical training and special equipment such as Doppler ultrasonic velocity signal probe which is not readily available in the primary care setting. This has led to under-utilization of ABI for the diagnosis of PAD despite strong guideline recommendations and unsuitable as a screening tool in the primary care setting. Other diagnostic tests for PAD such as duplex ultrasound, magnetic resonance or computed tomography angiography are even less readily accessible, costly and can potentially causes harm to patients in the form of radiation and contrast reaction. Questionnaires such as the Rose Questionnaire or Edinburgh Questionnaire have been validated to identify PAD patients with claudication symptoms. Although these questionnaires have high specificity of \>90%, their sensitivity is much lower at 20-30%.They are also time consuming to administer at scale in the outpatient setting. Therefore, questionnaires alone are not widely adopted for PAD screening in the primary care setting. Recently, a single claudication question has been proposed as a simpler and easier to administer screening tool for PAD which has high specificity but is also limited by low sensitivity.Therefore, there is an unmet clinical need for an alternative assessment tool for PAD screening that is more sensitive than currently available claudication questionnaires and can be easily administered in the primary care setting. In this study, we aim to evaluate the diagnostic accuracy of a novel assessment tool consisting of a single claudication question combined with symptom-limited APP test in detection of PAD using resting and/or exercise ABI as the reference. This screening tool is simple to use and has the potential to be self administered without supervision whereby reducing time and costs of screening.

Conditions

• Peripheral Arterial Disease

Interventions

DIAGNOSTIC_TEST

Active pedal plantarflexion (APP) test

Active pedal plantarflexion (APP) test

Sponsors & Collaborators

• Professor Bryan Ping Yen YAN (byan)

  collaborator UNKNOWN

• Chinese University of Hong Kong

  lead OTHER

Eligibility

Min Age

45 Years

Max Age

79 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2021-06-10

Primary Completion

2023-05-31

Completion

2023-12-30

Countries

• Hong Kong

Study Locations