Agreement Between StepWatch3 and ActiGraph wGT3X+ for Measuring Step-Based Metrics in People With Peripheral Artery Disease.

The authors investigated the agreement between StepWatch3™ (SW3) and ActiGraph™ wGT3X+ monitors for measuring step-based metrics in patients with peripheral artery disease and older adults. In 23 patients with peripheral artery disease and 38 older participants, the authors compared the metrics obtained during an outdoor (400-m track) walking session (step count) and a 7-day free-living period (step count and 60/30/5/1-min maximal or peak step accumulation) using the SW3 (ankle) and the wGT3X+ (hip) with the low-frequency extension filter enabled (wGT3X+/LFE) or not (wGT3X+/N). During outdoor walking session, agreement was high, particularly for wGT3X+/LFE: correlations ≥.98, median absolute percentage errors <1%, and significant equivalence using a ± 15% equivalence zone or narrower. In free living, no wGT3X+ method was equivalent to SW3 for step count. The wGT3X+/LFE was equivalent to SW3 regarding all step accumulation metrics using a ± 20% equivalence zone or narrower, with median absolute percentage errors <11%. The wGT3X+/LFE method is the best option for comparisons with SW3 in peripheral artery disease and older adults.

"Should I stay or should I go now?" Recovery time effect on walking capacity in symptomatic peripheral artery disease.

The objective of the study was to investigate the effect of recovery time on walking capacity (WC) throughout repeated maximal walking bouts in symptomatic lower-extremity peripheral artery disease (PAD). The effect of recovery time on WC (maximal walking time) was determined in 21 participants with PAD in three experimental conditions [recovery time from 0.5 to 9.5 min + a self-selected recovery time (SSRT)]: 1) 11 repeated sequences of two treadmill walking bouts (TW-ISO); 2) a single sequence of seven treadmill walking bouts (TW-CONS); 3) a single sequence of seven outdoor walking bouts (OW-CONS). Exercise transcutaneous oxygen pressure changes were continuously recorded as an indirect measure of ischemia. An individual recovery time (IRT) beyond which WC did not substantially increased was determined in participants with a logarithmic fit. At the group level, mixed models showed a significant effect (P < 0.001) of recovery time on WC restoration. At the participant level, strong logarithmic relationships were found (median significant R2 ≥ 0.78). The median SSRT corresponded to a median work-to-rest ratio >1:1 (i.e., a lower recovery time in view of the corresponding previous walking time) and was related to unrecovered ischemia and a WC restoration level of <80%. A median work-to-rest ratio of ≤1:2 allowed full recovery of ischemia and full restoration of WC. The IRT ratio was between 1:1 and 1:2 and corresponded to the start of recovery from ischemia. Recovery time affects the restoration level of WC during repeated maximal walking bouts in symptomatic PAD. Meaningful variations in WC restoration were related to specific levels of work-to-rest ratios.NEW & NOTEWORTHY This study demonstrated that there is a significant and mostly logarithmic effect of recovery time on walking capacity in people with symptomatic PAD. This study revealed that a median work-to-rest ratio >1:1 leads to the resumption of walking with unrecovered ischemia and precludes the restoration of full walking capacity, whereas a work-to-rest ratio ≤1:2 allowed walking capacity to fully be restored.

Comparison of Activity Monitors Accuracy in Assessing Intermittent Outdoor Walking.

PURPOSE: This study aimed to determine and compare the accuracy of different activity monitors in assessing intermittent outdoor walking in both healthy and clinical populations through the development and validation of processing methodologies. METHODS: In study 1, an automated algorithm was implemented and tested for the detection of short (≤1 min) walking and stopping bouts during prescribed walking protocols performed by healthy subjects in environments with low and high levels of obstruction. The following parameters obtained from activity monitors were tested, with different recording epochs0.1s/0.033s/1s/3s/10s and wearing locationsscapula/hip/wrist/ankle: GlobalSat DG100 (GS) and Qstarz BT-Q1000XT/-Q1000eX (QS) speed; ActiGraph wGT3X+ (AG) vector magnitude (VM) raw data, VM counts, and steps; and StepWatch3 (SW) steps. Furthermore, linear mixed models were developed to estimate walking speeds and distances from the monitors parameters. Study 2 validated the performance of the activity monitors and processing methodologies in a clinical population showing profile of intermittent walking due to functional limitations during outdoor walking sessions. RESULTS: In study 1, GS1s, scapula, QS1s, scapula/wrist speed, and AG0.033s, hip VM raw data provided the highest bout detection rates (>96.7%) and the lowest root mean square errors in speed (≤0.4 km·h-1) and distance (<18 m) estimation. Using SW3s, ankle steps, the root mean square error for walking/stopping duration estimation reached 13.6 min using proprietary software and 0.98 min using our algorithm (total recording duration, 282 min). In study 2, using AG0.033s, hip VM raw data, the bout detection rate (95% confidence interval) reached 100% (99%-100%), and the mean (SD) absolute percentage errors in speed and distance estimation were 9% (6.6%) and 12.5% (7.9%), respectively. CONCLUSIONS: GPS receivers and AG demonstrated high performance in assessing intermittent outdoor walking in both healthy and clinical populations.

Effects of Remote Ischemic Pre-Conditioning to Prevent Contrast-Induced Nephropathy after Intravenous Contrast Medium Injection: A Randomized Controlled Trial.

OBJECTIVE: We aimed to assess the effects of remote ischemic pre-conditioning (RIPC) on the incidence of contrast-induced nephropathy (CIN) after an intravenous (IV) or intra-arterial injection of contrast medium (CM) in patient and control groups. MATERIALS AND METHODS: This prospective, randomized, single-blinded, controlled trial included 26 patients who were hospitalized for the evaluation of the feasibility of transcatheter aortic valve implantation and underwent investigations including contrast-enhanced computed tomography (CT), with Mehran risk scores greater than or equal to six. All the patients underwent four cycles of five minute-blood pressure cuff inflation followed by five minutes of total deflation. In the RIPC group (n = 13), the cuff was inflated to 50 mm Hg above the patient's systolic blood pressure (SBP); in the control group (n = 13), it was inflated to 10 mm Hg below the patient's SBP. The primary endpoint was the occurrence of CIN. Additionally, variation in the serum levels of cystatin C was assessed. RESULTS: One case of CIN was observed in the control group, whereas no cases were detected in the RIPC group (p = 0.48, analysis of 25 patients). Mean creatinine values at the baseline, 24 hours after injection of CM, and 48 hours after injection of CM were 88 ± 32 µmol/L, 91 ± 28 µmol/L and 82 ± 29 µmol/L, respectively (p = 0.73) in the RIPC group, whereas in the control group, they were 100 ± 36 µmol/L, 110 ± 36 µmol/L, and 105 ± 34 µmol/L, respectively (p = 0.78). Cystatin C values (median [Q1, Q3]) at the baseline, 24 hours after injection of CM, and 48 hours after injection of CM were 1.10 [1.08, 1.18] mg/L, 1.17 [0.97, 1.35] mg/L, and 1.12 [0.99, 1.24] mg/L, respectively (p = 0.88) in the RIPC group, whereas they were 1.11 [0.97, 1.28] mg/L, 1.13 [1.08, 1.25] mg/L, and 1.16 [1.03, 1.31] mg/L, respectively (p = 0.93), in the control group. CONCLUSION: The risk of CIN after an IV injection of CM is very low in patients with Mehran risk score greater than or equal to six and even in the patients who are unable to receive preventive hyperhydration. Hence, the Mehran risk score may not be an appropriate method for the estimation of the risk of CIN after IV CM injection.

Using wearable monitors to assess daily walking limitations induced by ischemic pain in peripheral artery disease.

PURPOSE: To develop, assess the feasibility of, and determine the clinical validity of an event-based analysis method using wearable monitors to quantify walking pain manifestations (WPMs) and stops induced by walking pain (SIWPs) during daily life walking in people with peripheral artery disease (PAD). METHODS: The following two conditions were studied: a standardized outdoor walking session (OWS) and a seven-day free-living measurement (FLM) period. The PAD participants (n = 23) wore an accelerometer and a watch. They were asked to press the event marker button on the watch to indicate events related to WPMs and SIWPs. To assess the clinical validity of the method, the computed pain-free walking time (PFWT) and maximal walking time (MWT) were compared with the PFWT and MWT assessed using standard treadmill walking protocols, respectively. RESULTS: Following OWSs, the PFWT[OWS] and MWT[OWS] were significantly correlated with the PFWT[Strandness] (r = .955, P < .001) and MWT[Strandness] (r = .821, P < .001), respectively. During the FLM, PAD participants experienced only 2 WPMs/day and 1 SIWP/day, although severely limited on the treadmill and during the OWS. The average WPMs/day were moderately correlated with the PFWT[Strandness] (r = -.54, P = .016). The PFWT[FLM] was on average 12 times longer than the PFWT[Strandness] . Interestingly, the intensity of the walking bouts as assessed by the accelerometer counts during the FLM was significantly lower than that during the OWS (45 ± 15 vs 66 ± 20 counts/s, P < .001). CONCLUSION: This new method offers opportunities for studies investigating the experience of living with PAD and the assessment of daily life walking capacity for both diagnostic and therapeutic purposes.

Impact of an Educational Intervention on Ankle-Brachial Index Performance Among Medical Students and Fidelity Assessment at Six Months.

BACKGROUND: The resting ankle-brachial index (ABI) is a clinical test to diagnose peripheral artery disease. The Wyatt's score has been proposed to assess the students' performance on ABI measurement on a healthy volunteer (HV). No study has shown that this score is sensitive to different teaching methods. In this randomized controlled trial, we wanted to determine whether didactic learning alone or didactic learning combined with experiential learning improves proficiency in the ABI procedure assessed by the Wyatt's score. METHODS: Medical students (n = 30) received a didactic learning, including (1) a presentation of the ABI guidelines and (2) a video demonstration. Each student was then randomized into 2 groups ("the no experiential learning group" and "the experiential learning group"). An initial evaluation was performed after the didactic learning and then the final evaluation at the end of the intervention. A student was considered to be proficient when he performed a correct ABI procedure on an HV. The correct procedure corresponds to the following: (1) correctly answered Wyatt's score and (2) a difference in the ABI measurement between a professor in vascular medicine and a student was ≤0.15. RESULTS: No student was proficient at the initial evaluation. At the final evaluation, there was a significant difference between the number of proficient students for the Wyatt's score depending on their learning group [didactic alone (1/10) or didactic + experiential training (15/20)] and also for the ABI procedure [didactic alone (0/10) or didactic + experiential training (16/20)]. At 6 months, among the 12 students who passed the final evaluation, 4 students passed both the Wyatt's score and the ABI measurement. CONCLUSIONS: Our study demonstrates that the Wyatt's score was sensitive to an educational intervention and no improvement was found in the case of "no experiential learning." The Wyatt's score could be used to evaluate the student on ABI measurement after an educational intervention. TRIAL REGISTRATION: A randomized controlled trial was conducted in the Vascular Medicine Department of Rennes University Hospital (France). This was approved by the ethics review board of our institution (no. 16.150).

Noninvasive Peripheral Artery Disease Screening Tools: A Deficient Knowledge among French Vascular Residents from 4 Medical Schools.

BACKGROUND: Ankle-brachial index (ABI) at rest, postexercise ABI, and toe-brachial index (TBI) are essential diagnostic tools recommended for peripheral artery disease (PAD) diagnosis. Our study investigates the level of knowledge on these 3 tests among vascular medicine residents from 4 French medical schools in France. METHODS: We included 19 vascular medicine residents in a cross-sectional study. During an annual obligatory seminar, all residents accepted to fill 3 questionnaires concerning knowledge about these 3 tests. RESULTS: All residents accepted to fill 3 questionnaires. None of the residents correctly knows how to perform all pressure measurements (ABI, postexercise ABI, and TBI). Two residents had the knowledge to perform the whole ABI at rest procedure, whereas no resident had the knowledge to perform neither the postexercise ABI (P = 0.48) nor the TBI (P = 0.48). Twelve residents correctly completed the question regarding the interpretation of ABI at rest, whereas 2 correctly completed the postexercise ABI question (P = 0.001) and 4 the TBI question (P = 0.02). The number of residents who have performed more than 20 measurements is higher regarding ABI at rest than postexercise ABI and TBI (84%, 5%, and 37% respectively; P < 0.001 and P = 0.006 respectively) and significantly less often in postexercise ABI than TBI (5% vs. 37%; P = 0.04). CONCLUSIONS: This study shows for the first time that residents' knowledge of pressure measurements (resting-ABI, postexercise ABI, and TBI) of 4 French medical school are insufficient although the importance of pressure measurement has been strongly highlighted by the newly released PAD guidelines (2016) for PAD diagnosis.

How to become proficient in performance of the resting ankle-brachial index: Results of the first randomized controlled trial.

The resting ankle-brachial index (ABI) is a first-line test to diagnose peripheral artery disease (PAD). No randomized controlled trial (RCT) has yet been conducted to determine the best teaching method to become proficient in the ABI procedure. We conducted a monocentric RCT to determine whether didactic learning alone or didactic learning combined with experiential learning improved proficiency in the ABI procedure. Medical students ( n = 30) received didactic learning, including (i) a presentation of the ABI guidelines and (ii) a video demonstration. Each student was then randomized into two groups ('no experiential learning group' and 'experiential learning group'). An initial evaluation was performed after the didactic learning and a final evaluation at the end of the intervention. A student was considered to be proficient when he or she performed a correct ABI procedure on a healthy individual and a patient. The correct procedure corresponds to (i) following guidelines and (ii) a difference in ABI measurement between a vascular specialist and a student of ≤ 0.15. No student was proficient at the initial evaluation. At the final evaluation, in the didactic learning group, the number of proficient students was not improved compared with the initial evaluation (0/10 vs 1/10). In the experiential learning group, the number of proficient students was significantly improved (0/20 vs 11/20; p < 0.05). At the final evaluation, there was a significant difference between the number of proficient students depending on their learning group. In conclusion, didactic learning alone is insufficient to gain proficiency in the ABI procedure. Combining didactic learning with experiential learning significantly improved the students' proficiency.

Accuracy of a low-cost global positioning system receiver for estimating grade during outdoor walking.

The aim of this study was to assess, for the first time, the accuracy of a low-cost global positioning system (GPS) receiver for estimating grade during outdoor walking. Thirty subjects completed outdoor walks (2.0, 3.5 and 5.0 km · h-1) in three randomized conditions: 1/level walking on a 0.0% grade; 2/graded (uphill and downhill) walking on a 3.4% grade; and 3/on a 10.4% grade. Subjects were equipped with a GPS receiver (DG100, GlobalSat Technology Corp., Taiwan; ~US$75). The GPS receiver was set to record at 1 Hz and its antenna was placed on the right shoulder. Grade was calculated from GPS speed and altitude data (grade = altitude variation/travelled distance × 100). Two methods were used for the grade calculation: one using uncorrected altitude data given by the GPS receiver and another one using corrected altitude data obtained using map projection software (CartoExploreur, version 3.11.0, build 2.6.6.22, Bayo Ltd, Appoigny, France, ~US$35). Linear regression of GPS-estimated versus actual grade with R 2 coefficients, bias with 95% limits of agreement (±95% LoA), and typical error of the estimate with 95% confidence interval (TEE (95% CI)) were computed to assess the accuracy of the GPS receiver. 444 walking periods were performed. Using uncorrected altitude data, we obtained: R 2 = 0.88 (p < 0.001), bias = 0.0 ± 6.6%, TEE between 1.9 (1.7-2.2)% and 4.2 (3.6-4.9)% according to the grade level. Using corrected altitude data, we obtained: R 2 = 0.98 (p < 0.001), bias = 0.2 ± 1.9%, TEE between 0.2 (0.2-0.3)% and 1.0 (0.9-1.2)% according to the grade level. The low-cost GPS receiver used was weakly accurate for estimating grade during outdoor walking when using uncorrected altitude data. However, the accuracy was greatly improved when using corrected altitude data. This study supports the potential interest of using GPS for estimating energy expenditure during outdoor walking.

Exercise transcutaneous oxygen pressure measurement has good sensitivity and specificity to detect lower extremity arterial stenosis assessed by computed tomography angiography.

Peripheral artery disease (PAD) is a highly prevalent disease diagnosed by the use of ankle-brachial index (ABI) at rest. In some clinical conditions (diabetes, renal insufficiency, advanced age), ABI can be falsely normal and other tests are required for the PAD diagnosis (American Heart Association statement). This study was conducted to determine the accuracy of exercise transcutaneous oxygen pressure measurement (exercise-TcPo2) in detection of arterial stenosis ≥50% using computed tomography angiography (CTA) as the gold standard.We retrospectively analyzed consecutive patients referred to our vascular unit (University Hospital, Rennes, France) for exercise-TcPo2 testing from 2014 to 2015. All included patients had a CTA performed within 3 months of the exercise-TcPo2 test. Exercise-TcPo2 was performed on treadmill (10% slope; 2 mph speed). We calculated the Delta from Resting Oxygen Pressure (DROP) index (expressed in mm Hg) at the proximal and distal levels. Two blinded physicians performed stenosis quantification on CTA. The receiver operating characteristic (ROC) curve was used to define a cutoff point to detect arterial stenosis ≥50%, stenosis ≥60%, and stenosis ≥70%.A total of 34 patients (mean age 64 ±â€Š2 years old; 74% men) were analyzed. The highest areas under the curve (AUC) were found for 60% stenosis at both proximal and distal levels. For stenosis ≥50%, sensitivity and specificity of proximal minimal DROP were 80.9% [67.1-89.7], 81.0% [59.3-92.7] respectively. For stenosis ≥50%, sensitivity and specificity of distal minimal DROP were 73.2% [60.3-83.1], 83.3% [53.8-96.2], respectively. For stenosis ≥60%, sensitivity and specificity of proximal minimal DROP were 82.5% [67.6-91.5] and 85.7% [67.7-94.8] respectively. For stenosis ≥60%, sensitivity and specificity of distal minimal DROP were 80.4% [67.3-89.1] and 88.2% [64.2-97.7], respectively. For stenosis ≥70%, sensitivity and specificity of proximal minimal DROP were 85.7% [67.7-94.8] and 75.0% [59.6-85.9] respectively. For stenosis ≥70%, sensitivity and specificity of distal minimal DROP were 86.0% [72.2-93.7] and 76.0% [56.1-88.7], respectively.Exercise-TcPo2 using a proximal minimal DROP value ≤-15 mm Hg or a distal minimal DROP value ≤-16 mm Hg is accurate to diagnose arterial stenosis especially stenosis ≥60% on the lower limbs. Exercise-TcPo2 is safe and noninvasive test that might be used in second line for PAD diagnosis.

Knowledge about ankle-brachial index procedure among residents: being experienced is beneficial but is not enough.

BACKGROUND: Ankle-brachial index (ABI) at rest is the main clinical tool to diagnose the presence of lower extremity peripheral artery disease (PAD). The method for ABI procedure (i.e., measurement, calculation and interpretation) is standardised and guidelines were published in 2012. This study sought to: i) assess knowledge about the three major steps of the ABI procedure (i.e., measurement, calculation and interpretation) among residents from different medical schools, ii) compare the ABI knowledge of experienced residents (i.e., who have already performed ABI procedure more than 20 times) with the knowledge of inexperienced residents, and iii) describe the most common errors by residents. METHODS: Residents from six medical schools were invited to complete a questionnaire about the ABI procedure. RESULTS: Sixty-eight residents completed the questionnaire. None of them knew how to perform the entire ABI procedure. Overall, 22%, 13% and 41% of residents correctly answered questions about ABI measurement, ABI calculation and ABI interpretation, respectively. Score comparisons underlined the fact that experienced residents (n = 26) answered ABI measurement questions to a significantly better level and had a significantly higher total score than inexperienced residents (n = 42) (P = 0.0485 and P = 0.0332, respectively). Errors were similar for most of the residents. CONCLUSIONS: Our study confirms that experienced residents have significantly better ABI procedure knowledge than inexperienced residents. However, none of them are able to perform the entire ABI procedure without any mistake with regard to current guidelines. It is important that training be given to residents in medical schools in order to improve their ABI procedure knowledge.

Remote Ischemic Preconditioning and Contrast-Induced Nephropathy: A Systematic Review.

BACKGROUND: The use of imaging is increasing in clinical practice either for diagnosis or intervention. In these aims, contrast medium (CM) is widely used. However, CM administration can induce contrast-induced nephropathy (CIN). The incidence of CIN varies from 2% to 50% depending on patient risk factors, and CIN is the third cause of renal insufficiency. To date, methods such as hyperhydration to prevent CIN have a low level of evidence. Remote ischemic preconditioning (RIPC), which has already proved its efficiency in the cardiology field, seems to be a promising technique for CIN prevention. The aim of this work was to carry out a systematic review of the literature of the randomized clinical studies on RIPC in the prevention of CIN in man. METHODS: We conducted a systematic review of randomized clinical studies on the RIPC in the prevention of CIN in man. Documentary sources were PubMed articles published until June 2015. Randomized clinical trials of RIPC in preventing CIN in human were reviewed. RESULTS: Five articles were selected for the analysis. One article studied the impact of RIPC in a population at high risk of CIN, whereas the other 4 analyzed populations at low, moderate or unknown risk of CIN. In 4 studies, except the later one, the risk of CIN was based on the Mehran score that was previously published. In the high-risk population, a decrease in the incidence of CIN was found in the RIPC group compared with the control group (12% against 40%; P = 0.002). Among the 3 other studies using the Mehran's score, one also demonstrated the interest of such a procedure in a subgroup of high-risk patients. A second one found a low incidence of CIN in the RIPC group ([5 of 47; 10%] as compared with a control group [17 of 47; 36%] P = 0.003) in patients at the low risk of CIN. In another low-risk population, a significant lower level of a biological marker (liver-type fatty acid-binding protein) that assesses a renal impairment was found in the RIPC compared with the control group. CONCLUSIONS: Only 5 studies were found in this search, which may constitute a limitation. However, RIPC appears as a promising method to prevent CIN since it is a noninvasive, low cost, easy, and safe method. More randomized controlled trials are needed to confirm these preliminary results.