Correlation Between Pedal Acceleration Time and Transcutaneous Oxygen Pressures - A Prognostic Tool for Wound Healing in the Diabetic Foot Population.

BACKGROUND: Pedal arch interrogation by ultrasound through systolic acceleration time measurement (Pedal Acceleration Time [PAT]) is a recently described technique that offers valuable insights into foot hemodynamics. Previous studies have demonstrated a correlation between PAT and the ankle-brachial index and PAT has been proposed as a prognostic tool for wound healing in patients with peripheral artery disease. This study aims to assess the correlation between PAT and Transcutaneous Pressure of Oxygen (TcPO2) in the diabetic foot population. METHODS: In this single-center cross-sectional study PAT and TcPO2 were measured in diabetic patients with ischemic foot ulcers. The assessment of wound status was performed between the 12th and 16th week after the first evaluation. The primary outcome was to assess the correlation between the values obtained for PAT and TcPO2. The secondary outcome was to establish a cut-off value for wound healing. RESULTS: Sixty limbs with ischemic foot ulcers were evaluated. The results showed a correlation between PAT and TcPO2 [F (1.52) = 16.928; R2 = 0.246; P < 0.001]. The receiver operating characteristics curve analysis showed an optimal cut-off value at PAT >186 ms for predicting a nonhealing ulcer with a 96% specificity (area under the curve = 0.774; confidence interval 0.648-0.872; P < 0.001). CONCLUSIONS: PAT showed a significant correlation with TcPO2 with high specificity to identify nonhealing foot ulcers due to insufficient foot perfusion with a potential prognostic value in the diabetic foot population.

The Utility of Advanced Lower-Extremity Duplex Using Pedal Acceleration Time in the Management of the Threatened Diabetic Foot.

BACKGROUND: Patients with diabetes and diffuse infrageniculate arterial disease who present with chronic limb-threatening ischemia require an exact anatomical plan for revascularization. Advanced pedal duplex can be used to define possible routes for revascularization. In addition, pedal acceleration time (PAT) can predict the success or failure of both medical and surgical interventions. METHODS: A retrospective review of patients who were referred to our group for unilateral limb-threatening ischemia with isolated infrageniculate disease was conducted. Pedal duplex and PAT at the base of the wound was performed before and 1 week after intervention. The primary endpoint was limb salvage at 1 year. Revascularization was defined as direct or indirect based on the angiosome concept. RESULTS: Fifty-four patients meeting inclusion criteria presented over a 5-year period (toe wound, n = 42; heel wound, n = 8; both, n = 4). At 1 year, 10 (18.5%) had required below-knee amputation, whereas the remainder had healed/improved. Limb salvage was predicted by absence of ongoing smoking, absence of dialysis, and postprocedural PAT (class I/II). Limb salvage did not correlate with direct versus indirect revascularization. CONCLUSIONS: Advanced lower-extremity duplex in conjunction with determining PAT at the area of concern is a useful technique for mapping the vasculature and identifying targets for revascularization in patients with diffuse infrageniculate disease. Target artery revascularization to the wound bed resulting in a PAT less than 180 msec is predictive of limb salvage, regardless of whether perfusion is direct or indirect.

A substantial number of patients with rest pain, ulceration or gangrene are unable to undergo current non-invasive perfusion testing-Could another modality be utilised?

Rest pain, ulceration and gangrene are hallmark features of chronic limb-threatening ischaemia (CLTI). Wound healing can be challenging, and this is compounded by an inability to measure lower limb perfusion via non-invasive tools such as toe pressure (TP). Novel perfusion tests, such as pedal acceleration time (PAT), may overcome some limitations. This study aimed to quantify the proportion of patients with CLTI that were unable to undergo TP measurement. Over a three-year duration, 344 consecutive patients with CLTI underwent PAT assessment (403 limbs). Overall, 32% of limbs were unable to undergo first toe TP, and 12.9% were unable to undergo first and second toe TP due to forefoot/digit amputation or tissue loss. Inability to measure first toe TP disproportionately impacted CLTI patients with diabetes compared to patients without diabetes (39.6% limbs (106/268); vs. 17% limbs (23/135); p < 0.001). Novel modalities may provide a useful tool for assessing perfusion in CLTI.

Hybrid superficial venous arterialization and endovascular deep venous arterialization.

We report on two venous arterialization (VA) techniques for treatment of CLTI in patients traditionally considered as having no treatment options for standard arterial endovascular or surgical bypass procedures. Screening and the preprocedural workup findings are outlined as deciding factors in determining a patient's fitness for the two techniques, with a focus on careful preprocedure arterial duplex ultrasound and assessment for vein suitability. Cardiac and infection screening are also factors in determining patient suitability for VA. In addition, radiographic assessment for the presence of medial artery calcification, which is used as a marker of technical difficulty and is a predictor of poor outcomes, is required. Ultimately, anatomic factors are used to determine the decision between hybrid superficial VA and or endovascular deep VA. Those with an occluded anterior tibial artery and suitable great saphenous vein are prioritized to hybrid superficial VA, and those with an occluded posterior tibial artery to endovascular deep VA. Both procedures are described in detail in this report of vascular and surgical techniques.

Techniques Providing Endpoints for Revascularization in Chronic Limb-Threatening Ischemia.

It is frequently difficult to estimate the revascularization endpoint in patients with chronic limb-threatening ischemia where there may be extensive multifocal multiarterial disease. There have been attempts to identify an endpoint for revascularization procedures, but none has become the standard of care. An ideal indicator of an endpoint can objectively quantify tissue perfusion, predict wound healing, and is easily and efficiently used intraprocedurally to assist real-time decision making on whether adequate perfusion has been reached. Candidate techniques to evaluate endpoints post-revascularization are discussed here.

Bringing the Vascular Lab Inside the Procedure Room.

The advantages of the vascular lab (VL) are a specialized knowledgeable team and a dedicated equipment which is transferrable to the procedure room to facilitate the procedure and gather information about the procedure endpoints. In this article, Registered Vascular Technologists (RVT) from various institutions discuss the basic and the complex ways the VL can be used inside a procedure room. The advantages of the vascular lab (VL) are a specialized knowledgeable team and dedicated equipment which is transferrable to the procedure room to facilitate the procedure and gather information about procedure endpoints. Such expertise may improve imaging guided access, enable complicated lesion crossing, and provide information about the success of the procedure. Below are the reports from practicing registered vascular technologists at the forefront of patient vascular care within institutions that have adopted the mobile intraprocedural VL idea in basic and complex real-world ways.

Commentary: Demystifying Doppler - revisiting a vital diagnostic tool.

Doppler is the most commonly utilised vascular assessment tool by podiatrists in Australia and the United Kingdom. Doppler is a key component of many international guidelines for vascular assessment. Used alongside pressure measurements such as ankle and toe-brachial indices, Doppler assists podiatrists to diagnose, triage and subsequently manage patients with peripheral arterial disease. This commentary aims to clarify the importance, technique, and interpretation of continuous wave handheld Doppler in podiatry practice. This commentary presents discussion on the equipment and optimal test conditions for use of Doppler, and guidance on the technique required in podiatry clinical practice. Furthermore, there is a focus on interpretation of the output from Doppler including both audio and visual output. There is in depth discussion about identifying pathology and integration into the clinical management plan.

Pedal Acceleration Time (PAT): A Novel Predictor of Limb Salvage.

BACKGROUND: In the setting of Peripheral Arterial Disease (PAD), pedal arch interrogation by ultrasound has not been well described. Patients with noncompressible vessels and/or open wounds of the foot may preclude the use of ankle-brachial indices, toe pressure measurements, or TcPO2, respectively. We propose that pedal artery interrogations with Pedal Acceleration Time (PAT) can be a predictor for limb salvage in patients with Chronic Limb-Threatening Ischemia (CLTI). METHODS: A retrospective review of a prospectively kept database was performed from 2018 to 2019. Patients with pending amputation due to severe infection (WIFI infection class 2 and 3) were excluded from the study. We identified 73 limbs with CLTI that fit the inclusion criteria. Data included WIFI classification, age, gender, cardiovascular risk factors, PAT, ABI, and TBI when reliable, were collected. PAT measurements were categorized into 4 classifications; 1 (40-120 msec), 2 (121-180 msec), 3 (181-224 msec), and 4 (Greater than 225 msec). Statistical analyses were performed. RESULTS: Seventy-three limbs with CLTI were included in our study. All patients underwent arterial revascularization with either percutaneous technique or arterial bypass. Limb salvage was achieved in 59 (81%) of the 73 limbs. All 59 limbs had a 2-classification improvement in their PAT following interventions. A total of 14 (19%) limbs without improvement in their PAT underwent above ankle level amputations. An improvement in PAT classes to class 1 or 2 is associated with limb salvage. CONCLUSIONS: Patients with noncompressible ankle pressures or nonobtainable toe pressures poses a challenge in the complete assessment of WIFI classification. Our group has shown that PAT can be used in the scoring system for severity of ischemia in conjunction with current WIFI classification. Our data suggests that limb salvage correlates with post procedure PAT in category 1 and 2. Therefore we propose that PAT be added as part of the WIFI classification.

Plantar Acceleration Time: A Novel Technique to Evaluate Arterial Flow to the Foot.

BACKGROUND: Arterial duplex ultrasound (DUS) and ankle-brachial indices (ABIs) are accepted methods for assessing lower limb arterial perfusion. However, in a significant number of diabetic patients, medial wall calcification often precludes an ABI measurement. Direct, noninvasive duplex imaging of the pedal arch in the setting of peripheral arterial disease (PAD) has not been well evaluated. Although plantar arch interrogation is new to vascular ultrasound, imaging the plantar arteries appears to be a reliable angiographic technique for critical limb ischemia. We sought to define the utility of Plantar Acceleration Time as a surrogate for ABIs. METHODS: Patients undergoing DUS including Plantar Acceleration Time for suspicion of PAD were retrospectively reviewed in a prospective database over a 1-year period. Two hundred fifty nondiabetic patients (499 limbs) with documented ABI were studied. Plantar Acceleration Time was calculated (milliseconds [msec]) in each limb in the lateral plantar artery. Statistical analyses were performed using linear regression and analysis of variance testing using Microsoft Excel database (version 2016; Microsoft Corp, Redmond, WA). Patients were then grouped into 4 classes based on their clinical symptoms and ABI. Plantar Acceleration Time was similarly grouped into 4 distinct classes and correlated with the clinical and ABI classes. RESULTS: Plantar Acceleration Time correlated significantly with ABI (P < 0.001). There were significant differences in Plantar Acceleration Times between each class based on ABI and clinical presentation (P < 0.001 for each): Class 1 Plantar Acceleration Times 89.9 ± 15.5 msec; Class 2, 152.3 ± 28.4 msec; Class 3, 209.8 ± 25.5 msec, and Class 4, 270.2 ± 35.3 msec. CONCLUSIONS: Plantar Acceleration Time demonstrates a high correlation with ABI in patients with compressible arteries. Based on our results we propose the following categories of Plantar Acceleration Time, which appear to correlate with both clinical and ABI findings. ABI of 0.90-1.3 correlates with a Plantar Acceleration Time of 0-120 msec, ABI of 0.69-0.89 correlates with a Plantar Acceleration Time of 121-180 msec, ABI of 0.40-0.68 correlates with a Plantar Acceleration Time of 181-224 msec, and an ABI of 0.00-0.39 correlates with a Plantar Acceleration Time of greater than 225 msec. Further studies are ongoing to confirm whether Plantar Acceleration Time may be a suitable substitute to ABIs in patients with noncompressible arteries that preclude meaningful ABIs and gives more information regarding targeted angiosome perfusion to the foot.