Author : Dr. Muriel A. Morilla- Buco
Novel Technique to Determine Foot Perfusion in PAD: Pedal Acceleration Time
Peripheral arterial disease (PAD) of the lower extremity is common in patients with cardiovascular risk factors such as diabetes mellitus, hypertension, dyslipidemia, and smoking history. The spectrum of PAD is broad, ranging from normal to occurrence of critical limb ischemia or gangrene. Patients with abnormal arterial flow may have no to minimal symptoms yet can progress to mild to moderate, severe and chronic limb threatening PAD without proper diagnosis and management. A comprehensive yet detailed physical examination of the lower extremities will entail meticulous interrogation in patients with PAD.
Part of the spectrum in lower extremity PAD is chronic limb
ischemia which will need aggressive medical and often surgical or
endovascular treatment. The key to decision is determining the
adequacy of blood flow in the lower extremities. The basic
diagnostic tests include getting the ankle-brachial index (ABI) and
the arterial duplex scan. However, medial arterial wall calcification may cause a falsely elevated ABI with no definite analysis if the foot has indeed adequate or inadequate arterial flow. There is also difficulty when there is wound limiting performance of ABI due to its location and patient's inability to tolerate the pain that inflation of the cuffs causes.
A novel parameter, called acceleration time, has been used in other vascular beds such as the carotid arteries. This parameter is novel in the field of vascular ultrasound. Pedal or plantar acceleration time measures the time in milliseconds from the onset of systole to the peak of systole in the waveform obtained from the pedal arteries. The Philippine Society of Vascular Medicine held its first webinar discussion on pedal acceleration time, a novel technique to determine arterial foot flow. Yours truly shared the recently concluded research from the Philippine Heart Center on the use plantar acceleration time to determine arterial foot flow in patients with PAD. Line up of speakers were Ms. Jill Sommerset, Dr. Yolanda Vea, and Dr. Beejay Feliciano. Ms. Jill Sommerset is an expert vascular sonologist and technical director at the Peacehealth Southwest Washington Medical Center in Vancouver, WA. With over 20 years experience, she has a deep interest for chronic limb threatening ischemia. She leads a multidisciplinary limb saving program. She is the owner of flow socks, an arterial map of the legs socks created to build a sense of unity among specialists. Dr. Yolanda Vea, with Filipino roots, is a vascular surgeon in Southwest Washington. She currently serves as the section chief of Vascular surgery in Vancouver Washington. She is the medical director for the wound healing and limb salvage program. She is passionate about amputation prevention in patients with diabetic foot ul
cer. Dr.
Beejay Feliciano is also a vascular surgeon, a graduate of University of California Davis. He completed his general surgery residency program in Virginia Mason Medical Center in 2009 and vascular surgery fellowship from Indiana University in 2011.
In this webinar lecture, the first study on pedal acceleration time
was discussed by yours truly. Together with PSVM, and speakers, the
webinar concluded a successful meeting and sharing about this
novel technique.
Speaker Ms. Jill Sommerset
Ms. Jill Sommerset, Dr. Vea and Dr. Feliciano gave background on their approach to patients with gangrene and chronic limb threatening ischemia. Accordingly, their practice entails rigorous patient care and close follow ups, minimizing the use of CT scan and other invasive procedures as much as possible. Pedal acceleration time has been their practice in their center as a tool to follow up improvement in wound healing. They use PAT as pre- and post-operative tool to gauge success in foot perfusion. This tool has not been included in all vascular guidelines but being utilized in their center. There were many good questions from the local audience and PAT has certainly piqued the interest of the vascular specialist because no additional and expensive devices are needed except what we already have in most vascular labs...the trusted ultrasound. The meeting was the start of collaboration of the Philippine Society of Vascular Medicine and international resource speakers, Ms. Sommerset, Dr. Vea and Dr. Feliciano from Vancouver, WA. It encourages more researches for pedal acceleration time in patients with lower extremity peripheral arterial disease, especially for chronic limb threatening ischemia. Research recommendations include the use of PAT as a monitoring tool in PAD patients undergoing PAD rehabilitation, pre- and post-intervention in patients with chronic limb threatening ischemia, the effects of cold temperature, smoking and vasodilators in PAT measurements and standardization of threshold values to be used in wound healing and improved perfusion. The event last December 5, 2020 was initiated and led by Dr. Ma. Theresa Abola after her communication with Ms. Sommerset about this novel technique on pedal acceleration time as a tool to be used in PAD patients in the Philippines. Further meetings and training in measurements of pedal acceleration time is expected soon. The goal of this venture is ultimately to save limbs.