Noninvasive Assessment of Aortic Pulse Wave Velocity by the Brachial Occlusion-Cuff Technique: Comparative Study

Cardiovascular diseases are one of most frequent cause of morbidity and mortality in the world. There is an emerging need for integrated, non-invasive, and easy-to-use clinical tools to assess accurately cardiovascular system primarily in the preventative medicine. We present a novel design for a non-invasive pulse wave velocity (PWV) assessment method integrated in a single brachial blood pressure monitor allowing for up to 100 times more sensitive recording of the pressure pulsations based on a brachial occlusion-cuff (suprasystolic) principle. The monitor prototype with built-in proprietary method was validated with a gold standard reference technique SphygmoCor VX device. The blood pressure and PWV were assessed on twenty-five healthy individuals (9 women, age (37 ± 13) years) in a supine position at rest by a brachial cuff blood pressure monitor prototype, and immediately re-tested using a gold standard method. PWV using our BP monitor was (6.67 ± 0.96) m/s compared to PWV determined by SphygmoCor VX (6.15 ± 1.01) m/s. The correlation between methods using a Pearson’s correlation coefficient was r = 0.88 (p < 0.001). The study demonstrates the feasibility of using a single brachial cuff build-in technique for the assessment of the arterial stiffness from a single ambulatory blood pressure assessment.

Morphophysiological characteristics of skin microcirculation types in patients with Dupuytren’s contracture

Aim– to investigate the patterns of cutaneous microcirculation and their relationship with structural vascular changes in palmar hypoderm in patients with Dupuytren’s disease.Material and methods. In 26 patients with Dupuytren’s contracture aged between 45 and 70 years, the microcirculation of palmar skin was assessed before the planned surgical treatment using ultrasound pulsed Doppler (Minimax-Doppler K, SP Minimax, St. Petersburg, Russia) with a high-frequency sensor of 20 MHz and laser Doppler flowmetry (BLF21, Transonic Systems Inc., USA). The local 3-minute arterial ischemic test was performed in all patients by putting the occlusion cuff on the forearm. Histological analysis of intra-operative tissue specimens was done using light microscopy (Carl Zeiss Primo Star microscope with 3.1 MP UCMOS video camera) MicroCapture Ver 6.6 program was used for data acquisition.Results. The normocirculatory type of hemodynamics (1) was found in 17 % of observations; hyperemic (2) – in 19 %, congestive-spastic (3) – in 42 %, and congestive-static (4) – in 21 %. Histologically type 1 was characterized with initial signs of constrictive arterial remodeling and capillary occlusion, 2 – with marked hyperemia of the microcirculatory bed and diapedesis of blood cells, inflammatory perivascular infiltrates, 3 – with significant narrowing and deformations of lumens in small arteries and hyalinosis of arterioles, 4 – with pronounced polymorphism of capillary loops, significant changes in arteries and veins.Discussion. Hyperemic type of microcirculation reflects high activity of autoimmune inflammation. Congestic-spastic type indicates a significant decrease in the reactivity of precapillary microvessels. Congestic-stasic type is accompanied by the most pronounced constrictive vascular remodeling and denervation of the vascular bed.Conclusion. Dupuytren’s contracture is characterized with predominance of pathological types of microcirculation in palmar skin, which must be taken into account in individualized protocols of additive therapy.

The Influence of Short-Term Occlusion on Dynamics of Arterial Circulation in Calf Muscles

Research background and hypothesis. KAATSU training is a method based on workout in a local hypoxic environment. For the justifi cation of its a detailed vascular response to circulatory disturbances is required.Research aim. The aim of this study was to investigate the peculiarities of reactive hyperaemia depending on the duration of occlusion and preliminary fi lling with blood of the occluded limb.Research methods. Arterial blood-fl ow intensity was measured by vein-occlusion plethysmography after 1, 2, and 3 minutes of occlusions. When the occlusion cuff was quickly infl ated with air above 250 mmHg, the amount of blood in vessels was close to the conditions of physiological norm. While the leg was lifted above the heart level for 30 seconds, the amount of blood in the calf decreased. A slow blowing the air into the cuff created a situation when the amount of blood in vessels had increased before the blood-fl ow was arrested. Research results. The peak blood-fl ow in the reactive hyperaemia phase depends on the duration of the occlusion and on the degree of fi lling with blood of segment under occlusion. The peak blood-fl ow readings were registered after occlusions conducted when the amount of blood in the limb had decreased before the occlusion and the lowest blood-fl ow readings was registered after occlusion done with the increased fi lling of vessels. Discussion and conclusions. The initial fi lling of vessels with blood or the degree of tension of endothelial cells of vascular wall is the most signifi cant infl uence on blood fl ow activation after short-term occlusions.Keywords: blood flow arrest, reactive hyperaemia, occlusion plethysmography.

Lack of Gender and Age Differences in Pain Measurements Following Exercise in People with Chronic Whiplash-Associated Disorders

Background: Individuals with chronic whiplash associated disorders (WAD) present persistent pain in the absence of structural pathology. In these people, altered central pain processing and central sensitization are observed. The role of personal factors, such as gender and age, on pain processing mechanisms in chronic WAD, however, is still unclear. Objectives: This study investigated possible gender- and age-related differences in selfreported and experimental pain measurements in people with chronic WAD. Besides the exercise-induced response on pain measurements between gender and age subgroups was recorded. Study Design: Case-control study. Setting: University Hospital, Brussels. Methods: Self-reported pain and experimental pain measurements (pressure pain thresholds [PPT], occlusion cuff pressure, temporal summation, and conditioned pain modulation) were performed in 52 individuals (26 chronic WAD patients and 26 healthy controls), before and after a submaximal cycle exercise. Results: Lower PPTs and occlusion cuff pressures were shown in chronic WAD in comparison with healthy controls. No gender and age differences regarding PPTs, occlusion cuff pressures and conditioned pain modulation were found in chronic WAD. Within the chronic WAD group, men showed higher self-reported pain compared to women and younger adults showed enhanced generalized pain facilitation compared to older adults. In addition, chronic WAD patients are able to inhibit exercise-induced hyperalgesia, but no gender and age differences in pain response following exercise were found. Limitations: This study was sufficiently powered to detect differences between the chronic WAD and control group. However, a sufficient power was not reached when patients were divided in age and gender groups. Furthermore, only mechanical stimuli were included in the experimental pain measurements. Besides, psychosocial factors were not taken into account. Conclusion: Some alterations of altered pain processing are present in chronic WAD patients, however not in response to exercise. No gender and age differences in pain measurements were observed in people with chronic WAD.

Improving Strength and Power in Trained Athletes With 3 Weeks of Occlusion Training

Purpose:To examine the effects of moderate-load exercise with and without blood-flow restriction (BFR) on strength, power, and repeated-sprint ability, along with acute and chronic salivary hormonal parameters.Methods:Twenty male semiprofessional rugby union athletes were randomized to a lower-body BFR intervention (an occlusion cuff inflated to 180 mmHg worn intermittently on the proximal thighs) or a control intervention that trained without occlusion in a crossover design. Experimental sessions were performed 3 times a week for 3 wk with 5 sets of 5 repetitions of bench press, leg squat, and pull-ups performed at 70% of 1-repetition maximum.Results:Greater improvements were observed (occlusion training vs control) in bench press (5.4 ± 2.6 vs 3.3 ± 1.4 kg), squat (7.8 ± 2.1 vs 4.3 ± 1.4 kg), maximum sprint time (−0.03 ± 0.03 vs –0.01 ± 0.02 s), and leg power (168 ± 105 vs 68 ± 50 W). Greater exercise-induced salivary testosterone (ES 0.84–0.61) and cortisol responses (ES 0.65–0.20) were observed after the occlusion intervention sessions compared with the nonoccluded controls; however, the acute cortisol increases were attenuated across the training block.Conclusions:Occlusion training can potentially improve the rate of strength-training gains and fatigue resistance in trained athletes, possibly allowing greater gains from lower loading that could be of benefit during high training loads, in competitive seasons, or in a rehabilitative setting. The clear improvement in bench-press strength resulting from lower-body occlusion suggests a systemic effect of BFR training.

Brachial artery modifications to blood flow-restricted handgrip training and detraining

Low load resistance training with blood flow restriction (BFR) can increase muscle size and strength, but the implications on the conduit artery are uncertain. We examined the effects of low-load dynamic handgrip training with and without BFR, and detraining, on measures of brachial artery function and structure. Nine male participants (26 ± 4 yr, 178 ± 3 cm, 78 ± 10 kg) completed 4 wk (3 days/wk) of dynamic handgrip training at 40% 1 repetition maximum (1RM). In a counterbalanced manner, one forearm trained under BFR (occlusion cuff at 80 mmHg) and the other under nonrestricted (CON) conditions. Brachial artery function [flow-mediated dilation (FMD)] and structure (diameter) were assessed using Doppler ultrasound. Measurements were made before training (pretraining), after training (posttraining), and after 2-wk no training (detraining). Brachial artery diameter at rest, in response to 5-min ischemia (peak diameter), and ischemic exercise (maximal diameter) increased by 3.0%, 2.4%, and 3.1%, respectively, after BFR training but not after CON. FMD did not change at any time point in either arm. Vascular measures in the BFR arm returned to baseline after 2 wk detraining with no change after CON. The data demonstrate that dynamic low-load handgrip training with BFR induced transient adaptations to conduit artery structure but not function.

Acute vascular occlusion in horses: effects on skeletal muscle size and blood flow

The purpose of this study was to demonstrate whether acute vascular occlusion was safe and if it would result in changes to limb muscle size in horses. Six healthy, unfit Standardbred mares were used. Horses (standing at rest) wore an occlusion cuff at the most proximal position of the left forelimb. The right forelimb was used as control. An occlusion pressure of 200 mmHg was set for 5 min followed by a 2 min recovery. Three sets of occlusions were given to each horse. Muscle thickness was measured using B-mode ultrasound. The circumference of the forelimb and first phalanx was measured using a flexible tape measure. Pulsed-wave Doppler was performed on the radialis artery with a 5–10 MHz mechanical transducer at baseline and at each occlusion. Peak flow velocity (PFV) and the flow velocity integral (FVI) were measured each time. Mid-forelimb, but not first phalanx, girth was increased (P<0.05) in the occluded but not in the control leg following occlusion. Extensor and flexor muscle thickness was increased (P<0.05) in the occluded but not in the control leg. There were no changes (P>0.05) in PFV or FVI at any measurement time point. Acute vascular occlusion may be a suitable and safe model for studying muscle hypertrophy in horses.

Flow-mediated dilation in human brachial artery after different circulatory occlusion conditions

Different magnitudes and durations of postocclusion reactive hyperemia were achieved by occluding different volumes of tissue with and without ischemic exercise to test the hypotheses that flow-mediated dilation (FMD) of the brachial artery would depend on the increase in peak flow rate or shear stress and that the position of the occlusion cuff would affect the response. The brachial artery FMD response was observed by high-frequency ultrasound imaging with curve fitting to minimize the effects of random measurement error in eight healthy, young, nonsmoking men. Reactive hyperemia was graded by 5-min occlusion distal to the measurement site at the wrist and the forearm and proximal to the site in the upper arm. Flow was further increased by exercise during occlusion at the wrist and forearm positions. For the two wrist occlusion conditions, flow increased eightfold and FMD was only 1 to 2% ( P > 0.05). After the forearm and upper arm occlusions, blood flow was almost identical but FMD after forearm occlusions was 3.4% ( P < 0.05), whereas it was significantly greater (6.6%, P < 0.05) and more prolonged after proximal occlusion. Forearm occlusion plus exercise caused a greater and more prolonged increase in blood flow, yet FMD (7.0%) was qualitatively and quantitatively similar to that after proximal occlusion. Overall, the magnitude of FMD was significantly correlated with peak forearm blood flow ( r = 0.59, P < 0.001), peak shear rate ( r = 0.49, P < 0.002), and total 5-min reactive hyperemia ( r = 0.52, P < 0.001). The prolonged FMD after upper arm occlusion suggests that the mechanism for FMD differs with occlusion cuff position.