Abstract 516: Electromagnetic Properties of Blood-flow for Screening of Peripheral Artery Disease

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Jerad Rogers ◽  
Balakumar Jayakumar ◽  
Jeremy Patterson ◽  
Kim Cluff
Keyword(s):  
Blood Flow ◽  
Electromagnetic Field ◽  
Peripheral Artery Disease ◽  
Point Of Care ◽  
Electromagnetic Properties ◽  
Limb Amputation ◽  
Specialized Training ◽  
Peripheral Artery ◽  
Skin Patch ◽  
Artery Disease

Peripheral artery disease (PAD) is a slowly progressive vascular disease characterized by abnormal narrowing of peripheral arteries through atherosclerosis. PAD often goes unnoticed and is heavily under diagnosed due to its initially asymptomatic features and if not detected early enough can lead to critical limb ischemia or limb amputation. Current PAD screening options are limited to the clinical setting and require specialized equipment, specialized training in operation, specialized training for interpretation of the results, and lack the ability to screen for PAD in a simple, cost effective point-of-care manner. In this study, our objective was to create a novel, non-invasive, point-of-care screening patch for the early detection of PAD. To attain our objective, we tested our hypothesis that electromagnetic changes in the permittivity and permeability of blood can be used to detect blood-flow abnormalities of PAD with a simple wireless biosensor - applied like a small adhesive bandage. When activated by an external RF wave, the skin patch developed an electromagnetic field that penetrates into its surroundings. Using a Vector Network Analyzer (VNA), we were able to quantify the skin patch’s electromagnetic field interactions with its surroundings. Using a human arm phantom with vascular network, synthetic blood, and heart pump the skin patch was able to measure pulsatile blood flow as shifts in the sensor’s resonant frequency. The results were validated using an ultrasound pulse wave Doppler which detected 50 bpm on the arm phantom. The smart skin patch was able to detect pulsatile flow with 100% accuracy when compared to ultrasound. These results strongly suggest that the patch may be capable of measuring pulsating blood-flow in a point-of-care fashion which does not require specialized training or expensive equipment. What’s more, is that this biosensor does not have batteries, no electrical components, and has wireless communication.

Abstract 13342: Patient Demographics, Clinical Characteristics, Medication Utilization, Medical Resource Use and Outcomes Associated with Patients with Symptomatic Peripheral Artery Disease

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Monica Reed Chase ◽  
Prakash Navaratnam ◽  
Howard Friedman ◽  
Kim Heithoff ◽  
Ross J Simpson
Keyword(s):  
Peripheral Artery Disease ◽  
Clinical Characteristics ◽  
Limb Amputation ◽  
Bleeding Complications ◽  
Medical Resource ◽  
Peripheral Artery ◽  
Vascular Events ◽  
Patient Demographics ◽  
Medication Utilization ◽  
Artery Disease

Background: Symptomatic peripheral artery disease (SPAD) [defined as intermittent claudication (IC) and/or critical limb ischemia requiring peripheral revascularization (PRV)] is associated with significant CV and PAD-related morbidity and mortality. However, the real world impact of SPAD has not been well characterized to date. Methods: An algorithm that selectively identifies SPAD patients using a combination of PAD related ICD-9 diagnostic and DRG codes, PRV CPT-4 procedure codes, and IC medication NDC codes was used to select study eligible patients from the MarketScan Commercial and Encounters database from 01/01/06 to 06/30/10. The earliest date of a record of SPAD was the index date and a period of 1 year pre- and 3 years post-index was the study time frame. Patients with stroke/TIA, with bleeding complications and contraindications to anti-platelet therapy were excluded. Descriptive statistics comparing patient demographics, clinical characteristics, medication utilization, medical resource utilization and outcomes (event risk estimates for MI, any stroke, revascularization (coronary and peripheral), limb amputation, acute ischemic event hospitalizations and costs) were generated. Results: A total of 16,663 patients (58.0% male; mean age (± SD) 67.2 ± 12.9 years) were identified with SPAD. SPAD patients had significant comorbidities with 31.5% CAD, 36.0% diabetes, 31.0% hyperlipidemia and 53.1% hypertension. Twenty percent (20%) of SPAD patients were on clopidogrel in the pre-index. Pre-index use of beta-blocker, ACE, ARB and statin use was 42.1%, 37.1%, 21.1% and 48.5% respectively. SPAD patients experienced CV events such as any stroke (8.9%), NSTEMI (4.1%), STEMI (4.8%) and UA (7.5%) in the post-index. SPAD patients also experienced a limb amputation (11.5%), endovascular PRV (17%), and open PRV (14.6%) in the post-index. Annualized SPAD-related hospitalization rates, inpatient costs and outpatients costs were significantly higher in the post-index (0.1 vs 0.01, $2,073 vs $175, $1,313 vs $936; all p<0.0001). Conclusion: In an insured population, SPAD patients have low utilization of preventive medications, high rates of major vascular events (both CV and PAD related) and high costs.

scholarly journals Eight weeks of nitrate supplementation improves blood flow and reduces the exaggerated pressor response during forearm exercise in peripheral artery disease

2018 ◽  
Vol 315 (1) ◽  
pp. H101-H108 ◽  
Author(s):  
Nicholas T. Kruse ◽  
Kenichi Ueda ◽  
William E. Hughes ◽  
Darren P. Casey
Keyword(s):  
Blood Flow ◽  
Peripheral Artery Disease ◽  
Pressor Response ◽  
Treated Group ◽  
Moderate Intensity ◽  
Peripheral Artery ◽  
Pressor Responses ◽  
Nitrate Supplementation ◽  
Artery Disease ◽  
Forearm Exercise

Peripheral artery disease (PAD) is characterized by a reduced blood flow (BF) and an elevated blood pressure (pressor) response during lower extremity exercise. Although PAD is evident in the upper extremities, no studies have determined BF and pressor responses during upper extremity exercise in PAD. Emerging evidence suggests that inorganic nitrate supplementation may serve as an alternative dietary strategy to boost nitric oxide bioavailability, improving exercising BF and pressor responses during exercise. The present study investigated 1) BF and pressor responses to forearm exercise in patients with PAD ( n = 21) relative to healthy age-matched control subjects ( n = 16) and 2) whether 8 wk of NaNO3 supplementation influenced BF and pressor responses to forearm exercise in patients with PAD. Patients with moderate to severe PAD were randomly assigned to a NaNO3 (1 g/day, n = 13)-treated group or a placebo (microcrystalline cellulose, n = 8)-treated group. Brachial artery forearm BF (FBF; via Doppler) and blood pressure (via finger plethysmography) were measured during mild-intensity (~3.5-kg) and moderate-intensity (~7-kg) handgrip exercise. The absolute change (from baseline) in FBF was reduced (except in the 3.5-kg condition) and BP responses were increased in patients with PAD compared with healthy control subjects in 3.5- and 7-kg conditions (all P < 0.05). Plasma nitrate and nitrite were elevated, exercising (7-kg) ΔFBF was improved (from 141 ± 17 to 172 ± 20 ml/min), and mean arterial pressure response was reduced (from 13 ± 1 to 9 ± 1 mmHg, P < 0.05) in patients with PAD that received NaNO3 supplementation for 8 wk relative to those that received placebo. These results suggest that the BF limitation and exaggerated pressor response to moderate-intensity forearm exercise in patients with PAD are improved with 8 wk of NaNO3 supplementation. NEW & NOTEWORTHY Peripheral artery disease (PAD) results in an exaggerated pressor response and reduced blood flow during lower limb exercise; however, the effect of PAD in the upper limbs has remained unknown. These results suggest that 8 wk of inorganic nitrate supplementation improves the blood flow limitation and exaggerated pressor response to moderate-intensity forearm exercise in PAD.

Abstract MP14: Proteinuria is Associated With a Greater Risk of Lower Limb Amputation in Patients With Peripheral Artery Disease

Circulation ◽  
2018 ◽  
Vol 137 (suppl_1) ◽  
Author(s):  
Jung-Im Shin ◽  
Morgan Grams ◽  
Josef Coresh ◽  
Alex Chang ◽  
Kunihiro Matsushita
Keyword(s):  
Peripheral Artery Disease ◽  
Lower Limb ◽  
Proportional Hazards ◽  
Cox Proportional Hazards ◽  
Lower Limb Amputation ◽  
Limb Amputation ◽  
Antiplatelet Drug ◽  
Peripheral Artery ◽  
Increased Risk ◽  
Artery Disease

Introduction: Proteinuria is shown to be associated with increased risk of peripheral artery disease (PAD). However, its association with the risk of lower limb amputation in patients with PAD is unknown. Hypothesis: We hypothesized that proteinuria is associated with the risk of amputation in patients with PAD in a graded fashion. Methods: We identified 3,388 PAD patients with data on urine dipstick proteinuria within two years prior to PAD diagnosis between 1997 and 2017 in the Geisinger Health System (mean age 69.7 years, 44.8% female, 97.4% non-Hispanic White, 57.8% diabetic). We quantified the association of proteinuria with the risk of amputation using Cox proportional hazards models, adjusting for demographics, calendar year, estimated glomerular filtration rate, HbA1c, comorbidities including diabetic retinopathy/neuropathy, and medication use (antiplatelet drug, statin, and renin-angiotensin system inhibitor). Results: There were 55.2% with negative dipstick proteinuria, 11.1% trace, 14.1% with 1+, and 19.5% with ≥2+. A total of 245 patients underwent amputations over a median follow-up of 3.4 years. Incidence rate of amputation was 1.15 per 100 person-years for dipstick negative, 1.47 for trace, 2.11 for 1+, and 3.78 for ≥2+. This dose-response relationship remained similar even after accounting for potential confounders (p-trend=0.015), with particularly evident association for ≥2+ of dipstick (an adjusted hazard ratio of 1.52 [95% confidence interval: 1.08-2.17, p=0.017) (Figure). When we added proteinuria to other covariates, the risk discrimination slightly improved (Δc-statistic 0.007 [0.001-0.014]). Conclusions: Higher proteinuria was associated with a greater risk of lower limb amputation among patients with newly diagnosed PAD. Our results suggest the importance of considering proteinuria in risk assessment of limb loss in PAD patients.

scholarly journals Systemic and regional hemodynamic response to activation of the exercise pressor reflex in patients with peripheral artery disease

2020 ◽  
Vol 318 (4) ◽  
pp. H916-H924 ◽  
Author(s):  
Danielle Jin-Kwang Kim ◽  
Marcos Kuroki ◽  
Jian Cui ◽  
Zhaohui Gao ◽  
J. Carter Luck ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Peripheral Artery Disease ◽  
Plantar Flexion ◽  
Peripheral Artery ◽  
Exercise Pressor Reflex ◽  
Femoral Blood Flow ◽  
Femoral Blood ◽  
Pressor Reflex ◽  
Artery Disease

Patients with peripheral artery disease (PAD) have an accentuated exercise pressor reflex (EPR) during exercise of the affected limb. The underlying hemodynamic changes responsible for this, and its effect on blood flow to the exercising extremity, are unclear. We tested the hypothesis that the exaggerated EPR in PAD is mediated by an increase in total peripheral resistance (TPR), which augments redistribution of blood flow to the exercising limb. Twelve patients with PAD and 12 age- and sex-matched subjects without PAD performed dynamic plantar flexion (PF) using the most symptomatic leg at progressive workloads of 2–12 kg (increased by 1 kg/min until onset of fatigue). We measured heart rate, beat-by-beat blood pressure, femoral blood flow velocity (FBV), and muscle oxygen saturation ([Formula: see text]) continuously during the exercise. Femoral blood flow (FBF) was calculated from FBV and baseline femoral artery diameter. Stroke volume (SV), cardiac output (CO), and TPR were derived from the blood pressure tracings. Mean arterial blood pressure and TPR were significantly augmented in PAD compared with control during PF. FBF increased during exercise to an equal extent in both groups. However, [Formula: see text] of the exercising limb remained significantly lower in PAD compared with control. We conclude that the exaggerated pressor response in PAD is mediated by an abnormal TPR response, which augments redistribution of blood flow to the exercising extremity, leading to an equal rise in FBF compared with controls. However, this increase in FBF is not sufficient to normalize the SmO2 response during exercise in patients with PAD. NEW & NOTEWORTHY In this study, peripheral artery disease (PAD) patients and healthy control subjects performed graded, dynamic plantar flexion exercise. Data from this study suggest that previously reported exaggerated exercise pressor reflex in patients with PAD is driven by greater vasoconstriction in nonexercising vascular territories which also results in a redistribution of blood flow to the exercising extremity. However, this rise in femoral blood flow does not fully correct the oxygen deficit due to changes in other mechanisms that require further investigation.

scholarly journals Individuals with Peripheral Artery Disease (PAD) and Type 1 Diabetes Are More Likely to Undergo Limb Amputation than Those with PAD and Type 2 Diabetes

2020 ◽  
Vol 9 (9) ◽  
pp. 2809
Author(s):  
Nidhi Jain ◽  
Manyoo A. Agarwal ◽  
Diana Jalal ◽  
Ayotunde O. Dokun
Keyword(s):  
Type 2 Diabetes ◽  
Type 1 Diabetes ◽  
Peripheral Artery Disease ◽  
Limb Amputation ◽  
Peripheral Artery ◽  
Type 2 Dm ◽  
Artery Disease ◽  
Type 1 Dm

Background: Limited data exist comparing how type 1 diabetes mellitus (DM) and type 2 DM may have differential effects on peripheral artery disease (PAD) severity. We aimed to study the association of type of DM with the procedure utilized in hospitalizations with a diagnosis of PAD. Methods: We used the national inpatient sample databases from 2003 to 2014 to identify hospitalizations with a diagnosis of PAD and type 1 or type 2 DM. Logistic regression was utilized to evaluate the association between type of DM and procedure utilized (amputation-overall, major, endovascular revascularization, surgical revascularization). Results: We identified 14,012,860 hospitalizations with PAD diagnosis and DM, 5.6% (n = 784,720) had type 1 DM. The patients with type 1 DM were more likely to present with chronic limb-threatening ischemia (CLTI) (45.2% vs. 32.0%), ulcer (25.9% vs. 17.7%), or complicated ulcer (16.6% vs. 10.5%) (all p < 0.001) when compared to those with type 2 DM. Type 1 DM was independently and significantly associated with more amputation procedures (adjusted odds ratio = 1.12, 95% confidence interval [CI] I 1.08 to 1.16, p < 0.001). Overall, in-hospital mortality did not differ between the individuals with type 1 and type 2 DM. The overall mean (95% CI) length of stay (in days) was 6.6 (6.5 to 6.6) and was significantly higher for type 1 DM (7.8 [7.7 to 8.0]) when compared to those with type 2 DM (6.5 [6.4 to 6.6]). Conclusion: We observed that individuals with PAD and type 1 DM were more likely to present with CLTI and ulcer and undergo amputation when compared to those with PAD and type 2 diabetes. Further studies are needed to better understand the underlying mechanisms behind these findings and to identify novel interventions to reduce the risk of amputation in patients with type 1 DM.

Abstract 15456: Enhanced Vasoconstrictor Sensitivity to Exercise Pressor Reflex Engagement in Peripheral Artery Disease

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Zhaohui Gao ◽  
Matthew D Muller ◽  
Cheryl Blaha ◽  
Aimee Cauffman ◽  
Kristen Brandt ◽  
...  
Keyword(s):  
Blood Flow ◽  
Peripheral Artery Disease ◽  
Plantar Flexion ◽  
Maximum Voluntary Contraction ◽  
Ankle Brachial Index ◽  
Peak Exercise ◽  
Peripheral Artery ◽  
Exercise Pressor Reflex ◽  
Pressor Reflex ◽  
Artery Disease

Exercise is associated with a rise in heart rate, blood pressure (BP) and blood flow to active skeletal muscle that is mediated by the exercise pressor reflex and modified by regional release of vasodilator factors. In peripheral artery disease (PAD) the exercise pressor reflex is enhanced and the ability to raise blood flow to the affected limb is impaired. To assess the functional impact of the enhanced exercise pressor reflex on regional blood flow in limbs affected by PAD, we determined beat-by-beat BP and mean blood velocity (MBV, Doppler) in the popliteal artery, and calculated vascular conductance index (VC, MBV/mean BP) in the exercising (ipsilateral) or contralateral resting leg during graded rhythmic plantar flexion exercise in 7 patients with symptomatic PAD (age 67±2 yrs, body-mass-index 27.9±1.1) and in 5 healthy age-matched controls (2 exercise trials with each leg). At peak exercise (2.0 kg, 1 contraction/sec), the pressor effect was greatest in PAD when exercise was performed with the “ischemic” leg (ankle-brachial index 0.58±0.05; mean ΔBP +9.1±2.0 mmHg), lower with the less affected leg (ankle brachial index 0.76±0.07; mean ΔBP +6.9±1.6 mmHg) and lowest in the controls (ankle brachial index 1.11±0.04; mean ΔBP +3.9±1.8 mmHg). In controls, VC increased in the exercising leg ( P <0.05) but did not change in the inactive contralateral leg ( P =NS). Similarly, in PAD, VC increased in the exercising “ischemic” leg ( P <0.05) but did not change in the inactive contralateral leg ( P =NS). In sharp contrast, while VC increased in the less affected exercising leg ( P <0.05), in the contralateral resting “ischemic” leg VC decreased by 24±10% ( P <0.05). Similarly, when static handgrip at 30% maximum voluntary contraction to fatigue served as the exercise stimulus, vasoconstriction was noted in the “ischemic” leg (n=5; P <0.05). Thus, unlike in the exercising leg, in the resting “ischemic” leg activation of the exercise pressor reflex resulted in substantial vasoconstriction. This suggests that despite activation of peripheral vasodilator mechanisms downstream to the arterial obstruction, the vasculature of the “ischemic” leg is exquisitely sensitive to reflex vasoconstriction.

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