Location of ischemia and ischemic pain intensity affect spatiotemporal parameters and leg muscles activity during walking in patients with intermittent claudication.

The ways in which locations of ischemia and ischemic pain affect spatiotemporal gait parameters and leg electromyographic activity during walking have never been investigated in patients with peripheral arterial disease presenting intermittent claudication. Two groups were classified according to unilateral location of ischemia (distal, n = 10, or proximo-distal, n = 12). Patients described pain and three gait phases-initial pain-free, onset of pain and maximum pain-were analyzed. Patients with proximo-distal ischemia walked less (230 ± 111 m vs 384 ± 220 m), with increased step length, step time (+ 5.4% and + 5.8%) and reduced cadence (- 8.2%), than patients with distal ischemia. In both, the peaks of vertical ground reaction force were reduced in maximum pain (Peak1-distal: - 11.4%, Peak1-proximo-distal: - 10.3%; Peak2-distal: - 11.8%, Peak2-proximo-distal: - 9.0%). In the proximo-distal group, tibialis anterior activation peak and time were lower than in the distal group (- 4.5% and - 19.7%). During the maximum pain phase, this peak decreased only in the proximo-distal group (- 13.0%), and gastrocnemius medialis activation peak and time decreased in both groups (- 2.5% in distal and - 4.5% in proximo-distal). Thus, proximo-distal ischemia leads to more adverse consequences in gait than distal ischemia only. Increasing ischemic pain until maximum, but not onset of pain, induced gait adaptations.

Gait alterations in patient with intermittent claudication: Effect of unilateral vs bilateral ischemia.

BACKGROUND: We seek to evaluate whether ischemia extent (unilateral or bilateral) impacts spatiotemporal and neuromuscular gait parameters differently in patients with peripheral arterial disease and presenting intermittent claudication (PAD-IC). METHODS: Two groups of PAD-IC patients: unilateral (Unilat-IC; n = 15), bilateral (Bilat-IC; n = 15) and a group of control subjects with similar risk factors (n = 15) were evaluated during a constant load treadmill walking test. Spatiotemporal parameters and neuromuscular activation in tibialis anterior and gastrocnemius medialis were recorded. Patients were instructed to describe their pain during walking test, and three phases were analysed: pain-free, onset of pain and maximum pain in PAD-IC patients. FINDINGS: Single leg stance in the asymptomatic leg of Unilat-IC increases and becomes higher than the symptomatic leg and the Bilat-IC legs at maximum pain. Step time is higher and cadence is lower in PAC-IC than in controls. Tibialis anterior activation peak in Unilat-IC continuously decreases between phases and becomes lower than in Bilat-IC during maximum pain. Tibialis anterior activation time is higher in Bilat-IC and in the asymptomatic leg than in the symptomatic of Unilat-IC during all the phases. Gastrocnemius medialis activation peak in Bilat-IC decreases with pain. Gastrocnemius medialis activation time in the symptomatic leg of Unilat-IC presents a significant decrease between pain-free and maximum pain phases. INTERPRETATION: Ischemia impacts gait in PAD-IC patients differently according to its extent between legs compared to controls. Imbalance between legs in Unilat-IC induces compensatory mechanism and an asymmetrical pattern. Bilat-IC should not be simply considered as a 'double' Unilat-IC when evaluating gait.

Coactivation pattern in leg muscles during treadmill walking in patients suffering from intermittent claudication.

BACKGROUND: In patients with peripheral arterial disease and presenting intermittent claudication (PAD-IC), the pain due to ischemia impacts gait parameters, particularly in cases of unilateral disease. Deterioration of gait parameters in a pathological context is frequently associated with increased coactivation (simultaneous activation of agonist and antagonist muscles around a joint). RESEARCH QUESTION: Does unilateral PAD-IC affect the coactivation pattern during walking? Does the coactivation pattern change with increasing pain intensity? METHOD: We evaluated symptomatic and asymptomatic legs in 17 subjects with unilateral PAD-IC and 16 without PAD-IC (control group), during walking. Tibialis anterior (TA) and gastrocnemius medialis (GM) electromyographic activity, and peaks of vertical ground reaction force were recorded in this prospective study. We analyzed the coactivation index (CI(GM/TA)) during three periods (pain-free, pain and maximum pain) and phases of the gait cycle. Statistical analysis was carried out using the ANOVA procedure. RESULTS: During single support, CI(GM/TA) increases in the symptomatic leg during the pain period (+28 %) and in the asymptomatic leg during the maximum pain period (+29 %). During second double support, CI(GM/TA) increases in the symptomatic leg only (+49 %). In these gait phases, pain elicits differences in CI(GM/TA) between legs (p < 0.05). Second peak force decreases in the symptomatic leg only (-9%) and is negatively correlated with CI(GM/TA) during the three periods (r = -0.57; -0.76 and -0.78 respectively, p < 0.05). No difference is found in the control group. SIGNIFICANCE: The appearance and development of pain in the lower limbs is associated with a higher level of CI(GM/TA), revealing a compensatory gait pattern in PAD-IC patients. Optimal prevention, rehabilitation and re-training strategies for PAD-IC patients should take into consideration neuromuscular compensatory mechanisms between asymptomatic and symptomatic legs.

The hidden side of calf claudication: Hemodynamic and clinical results of treadmill testing in 584 patients complaining of isolated exertional calf pain.

BACKGROUND AND AIMS: Calf pain is the most frequent symptom of arterial claudication. We hypothesized that patients with self-reported isolated calf claudication have frequent exertional non-calf symptoms during objective laboratory testing, and that many would show not only distal, but also proximal ischemia. METHODS: We retrospectively analyzed the patients referred since 2016 for exercise transcutaneous oxygen pressure (Ex-tcpO2). The Edinburgh Claudication Questionnaire (ECQ) was self-completed before and during a treadmill test. For calf and non-calf (buttock and thigh) Ex-tcpO2, a lowest decrease of rest of oxygen pressure (DROP) < -15 mmHg was indicative of ischemia. We selected the patients that reported calf claudication only and analyzed minimal DROP and per-test ECQ observations. RESULTS: Exertional symptoms on a treadmill occurred in 526 (90.1%) of the 584 patients analyzed (65.6 ± 11.4 years old), with 391 (74.3%) of these symptoms affecting only the calf. Isolated calf ischemia with or without symptoms was found in only 139 (23.8%) patients. Overall, among the 584 patients self-reporting isolated calf symptoms, a perfect concordance between symptoms on a treadmill and Ex-tcpO2 (i.e. calf symptoms associated to calf ischemia) was observed in only 114 (19.5%) cases. CONCLUSIONS: Our study demonstrated that patients self-reporting exertional limb pain strictly limited to the calf may also have non-calf claudication on a treadmill and frequently show not-only-calf ischemia. These observations are important when planning reeducation or when studying the tissue consequences of ischemia in patients with claudication.

Rearfoot-forefoot profile defined by vertical ground reaction forces during gait is altered in patients with unilateral intermittent claudication.

Intermittent Claudication due to Peripheral Arterial Disease (PAD-IC) induces ischemic pain in exercising muscles, and therefore impaired gait. In a pathological context, the analysis of the Vertical component of Ground Reaction Force (VGRF) is frequently used to describe gait pattern. This paper aims to define gait profiles according to the relative difference between peaks of VGRF; a Rearfoot and a Forefoot profile revealing a more loading or push-off strategy. We evaluated 70 participants (24 with unilateral disease (Unilat-IC), 22 with bilateral disease (Bilat-IC) and 24 Controls) during a walk test on an instrumented treadmill. Results indicate that Unilat-IC patients present a Rearfoot-profile in both legs during the pain-free gait period, likely to stabilize their gait. With the onset and increase of pain, the asymptomatic leg changes for a Forefoot-profile. This asymmetrical pattern suggests that a compensatory mechanism occurred to unload the symptomatic (painful) leg, possibly creating an imbalance. In Bilat-IC and Controls subjects, a Forefoot-profile is found, with a symmetrical pattern. However, there is a trend for lower propulsive capacity in case of Bilat-IC due to ischemic pain, but patients did not have the ability to compensate as in Unilat-IC. Therefore, Bilat-IC should not be considered as a "double" Unilat-IC. This study highlights the existence of gait profiles based on VGRF in PAD-IC patients. These profiles are dependent on the type of disease. Analysis of these gait profiles can 1) provide a simple way to identify gait alterations and 2) participate in improving physical rehabilitation strategies in PAD-IC patients.

Specific slow tests are not mandatory in patients with extremely short standard (3.2 km/hr 10% slope) test durations during exercise oximetry.

AIM: To compare the transcutaneous oxygen pressure results observed in patients with severe walking limitation during standard procedures (3.2 km/hr, 10% slope) versus during a test performed at a low speed (2 km/hr, 10% slope). METHODS: In 31 patients, the decrease from rest of oxygen pressure (DROP) index was measured on both buttocks, both thighs and both calves during two consecutive tests on treadmill. The maximal walking time (MWT) and the minimal DROP values (DROPmin ) observed during the 2 tests were compared with t test. Correlation of DROPmin values during the slow and standard procedure was performed with linear regression. The -15 mmHg cut-off value defined for standard test interpretation was used arbitrarily for the interpretation of slow test results. RESULTS: MWT was 80 ± 52 s versus 376 ± 269 s at standard and slow speed, respectively (p < .001). No difference on all recorded DROPmin values at a standard (-9.5 ± 6.9 mmHg) and slow (-10.5 ± 7.9 mmHg) speed was found; n = 186, p = .168. Coefficient of correlation between DROPmin s found at the two tests was r = 0.820 (p < .01), with regression line close to the line of identity. With the identical -15 mmHg cut-off, 166 (89.2%) of 186 the results were classified similarly after standard and slow procedures. CONCLUSION: Specific slow treadmill procedures are not mandatory in patients with extremely short test durations when performing standard (3.2 km/hr 10% slope) exercise oximetry. In patients expected to be unable to walk at standard speed, the -15 mmHg normal limit seems to be valid for the interpretation of tests with a slow procedure (2.0 km/hr).

A pilot study of forearm microvascular impairment and pain while using a telephone.

OBJECTIVE: To determine if using a telephone can induce forearm pain and ischemia. DESIGN: Prospective case-control trial. SETTING: Vascular laboratory in the university hospital in Angers between September 2018 and March 2019. PARTICIPANTS: Fifteen apparently healthy subjects (controls) and 32 patients with suspected thoracic outlet syndrome (TOS) of vascular or non-vascular origin. INTERVENTION: Hand-holding a cellular phone to answer a call from investigators. MAIN OUTCOME MEASURES: Presence of forearm fatigue or pain (primary outcome), ability to hold the phone with each hand for 1 min (secondary outcome 1) and decrease in forearm transcutaneous oxygen pressure DROP index indicating forearm ischemia (secondary outcome 2). A DROP < -15 mm Hg defined ischemia. RESULTS: Answering a phone call resulted in 25(78%) patients with forearm fatigue or pain and in 18 (56%) cases in the inability to hold the phone for 1 min, on one or both arms in patients with suspected TOS, but never occurred in healthy volunteers (p < .05 and p < .001). The presence of ischemia was observed in one or both arms in 10 (31%) patients with proved TOS and was always associated to phone-induced pain. Three (20%) of the controls had phone-induced ischemia. All had asymptomatic TOS and remained asymptomatic during the phone test (p = .42 from suspected-TOS patients). CONCLUSION: The phone conversation resulted in pain in many patients with suspected TOS. Transcutaneous oximetry can document the underlying ischemia. Forearm phone-call-induced pain may be indicative of TOS provided that no earplug or headset is used. Trial registrationClinicalTrials.govNCT03355274.