Assessment of abnormal blood flow and efficacy of treatment in patients with systemic sclerosis using a newly developed microwireless laser Doppler flowmeter and arm-raising test

Digital Ulcers in Systemic Sclerosis

Digital ulcers (DU) are one of the most common complication of Systemic Sclerosis (SSc)-related vasculopathy and represent an important burden for the patients as well as for the society. Still today there is no agreement on the definition, classification and cathegorization of DU even if they are of pivotal importance in clinical practice, for treatment choice and prognostic outcomes, as well as for clinical trials. DU management requires a dedicated multidisciplinary team, that must remain ever vigilant for the development of infective complications and gangrene throughout their disease course, as well as patient education that is crucial to obtain the best compliance to assure the success of the treatment. Currently several drugs are available for DU treatment but in the future, more investigations will be needed to ameliorate the approach and the systemic and local therapies.

Dasatinib for chronic myelogenous leukemia improves skin symptoms of systemic sclerosis

A 64-year-old man was diagnosed with limited cutaneous systemic sclerosis 5 years prior to this report. His sclerotic skin symptoms did not respond to oral low-dose prednisone (5-10 mg/day). Five years after the diagnosis, the patient presented with leukocytosis 3.8 × 109/L in a routine blood test, and was finally diagnosed with chronic-phase chronic myelogenous leukemia (CML). The leukemia responded optimally to initial dasatinib, and a complete cytogenetic response was achieved after 6 months of therapy. His skin symptoms dramatically improved in parallel with dasatinib therapy, as indicated by a decrease in the modified Rodnan skin score, from 12 points at diagnosis to 2 after 9 months. It has been reported that imatinib, a first-generation tyrosine kinase inhibitor, improves skin sclerosis in some patients with systemic sclerosis. To the best of our knowledge, this is the first report of simultaneous improvement of CML and limited cutaneous systemic sclerosis in response to dasatinib. Further study of the mechanism of action of dasatinib is crucial.

Detection of Site-Specific Blood Flow Variation in Humans during Running by a Wearable Laser Doppler Flowmeter

Wearable wireless physiological sensors are helpful for monitoring and maintaining human health. Blood flow contains abundant physiological information but it is hard to measure blood flow during exercise using conventional blood flowmeters because of their size, weight, and use of optic fibers. To resolve these disadvantages, we previously developed a micro integrated laser Doppler blood flowmeter using microelectromechanical systems technology. This micro blood flowmeter is wearable and capable of stable measurement signals even during movement. Therefore, we attempted to measure skin blood flow at the forehead, fingertip, and earlobe of seven young men while running as a pilot experiment to extend the utility of the micro blood flowmeter. We measured blood flow in each subject at velocities of 6, 8, and 10 km/h. We succeeded in obtaining stable measurements of blood flow, with few motion artifacts, using the micro blood flowmeter, and the pulse wave signal and motion artifacts were clearly separated by conducting frequency analysis. Furthermore, the results showed that the extent of the changes in blood flow depended on the intensity of exercise as well as previous work with an ergometer. Thus, we demonstrated the capability of this wearable blood flow sensor for measurement during exercise.

Useful method to monitor the physiological effects of alcohol ingestion by combination of micro-integrated laser Doppler blood flow meter and arm-raising test

Alcohol has a variety of effects on the human body, affecting both the sympathetic and parasympathetic nervous system. We examined the peripheral blood flow of alcohol drinkers using a micro-integrated laser Doppler blood flow meter (micro-electromechanical system blood flow sensor). An increased heart rate and blood flow was recorded at the earlobe after alcohol ingestion, and we observed strong correlation between blood flow, heart rate, and breath alcohol content in light drinkers; but not heavy drinkers. We also found that the amplitude of pulse waves measured at the fingertip during an arm-raising test significantly decreased on alcohol consumption, regardless of the individual's alcohol tolerance. Our micro-electromechanical system blood flow sensor successfully detected various physiological changes in peripheral blood circulation induced by alcohol consumption.

MRI of arterial flow reserve in patients with intermittent claudication: feasibility and initial experience

Objectives

The aim of this work was to develop a MRI method to determine arterial flow reserve in patients with intermittent claudication and to investigate whether this method can discriminate between patients and healthy control subjects.

Methods

Ten consecutive patients with intermittent claudication and 10 healthy control subjects were included. All subjects underwent vector cardiography triggered quantitative 2D cine MR phase-contrast imaging to obtain flow waveforms of the popliteal artery at rest and during reactive hyperemia. Resting flow, maximum hyperemic flow and absolute flow reserve were determined and compared between the two groups by two independent MRI readers. Also, interreader reproducibility of flow measures was reported.

Results

Resting flow was lower in patients compared to controls (4.9±1.6 and 11.1±3.2 mL/s in patients and controls, respectively (p<0.01)). Maximum hyperemic flow was 7.3±2.9 and 16.4±3.2 mL/s (p<0.01) and the absolute flow reserve was 2.4±1.6 and 5.3±1.3 mL/s (p<0.01), respectively in patients and controls. The interreader coefficient of variation was below 10% for all measures in both patients and controls.

Conclusions

Quantitative 2D MR cine phase-contrast imaging is a promising method to determine flow reserve measures in patients with peripheral arterial disease and can be helpful to discriminate patients with intermittent claudication from healthy controls.

Correlation between Changes in Leg Blood Flow and Ankle-Brachial Pressure Index: A Study Using Laser Doppler Flowmeter -The 1st Report-

OBJECTIVE

The objective of this study was to use non-invasive laser Doppler flowmeter to measure changes in blood flow in peripheral vessels in the legs before and after stress induced by leg elevation stress test and investigate correlations with the ankle-brachial pressure index (ABI).

METHODS

Subjects included 28 patients over 20 years of age (mean, 73 years) who reported chiefly of leg symptoms such as intermittent claudication, numbness, chills, or cramps had been examined at the study institution, and agreed to participate in the study. The ABI of both legs was measured, and patients were divided into two groups: low ABI (ABI ≤0.9) and normal ABI (ABI ≥0.9). Blood flow in the big toe was measured using a box-type laser Doppler flowmeter before, during, and after leg-elevation stress. Amplitude of the recorded waveform and changes in blood flow were compared.

RESULTS

Average ABI was 1.09 ± 0.10 in the normal ABI group (33 legs) and 0.68 ± 0.17 in the low ABI group (21 legs). Amplitude before and during stress was significantly smaller in the low ABI group than in the normal ABI group (p <0.01), and there was a significant correlation with ABI before and during stresses (r = 0.4606, r = 0.5048, respectively; p <0.05). Change in blood flow during stress was significantly lower in the low ABI group than in the normal ABI group (p <0.05). There was a significant correlation between change in blood flow during stress and ABI in both groups (r = 0.5073; p <0.05). There was also a significant correlation between change in blood flow and change in amplitude in both groups (r = 0.5477; p <0.05).

CONCLUSION

RESULTS of this study show, that comparing amplitude and change in blood flow before and after leg extension and elevation stress, there was a correlation between change in blood flow and amplitude, and ABI during stress. A box-type laser Doppler flowmeter may provide a means of screening for peripheral arterial disease.

Peripheral blood perfusion correlates with microvascular abnormalities in systemic sclerosis: a laser-Doppler and nailfold videocapillaroscopy study

OBJECTIVE

To investigate possible correlations between fingertip blood perfusion (FBP) status, assessed by laser Doppler flowmetry (LDF), and morphological microvascular abnormalities, detected by nailfold videocapillaroscopy (NVC), in patients with systemic sclerosis (SSc). The effects on FBP of intravenous (IV) treatment with the prostacyclin analog iloprost were also investigated.

METHODS

Thirty-four consecutive patients with SSc and 16 healthy subjects were evaluated. LDF was performed by analyzing blood perfusion at the fingertips in both hands. Patients with SSc were distributed into the appropriate NVC pattern of microangiopathy (early, active, and late). Iloprost was administered to inpatients with SSc by 24-hour IV infusion for 7 consecutive days (4 microg/h).

RESULTS

FBP was significantly lower in patients with SSc (p < 0.05) compared to controls. Heating of the LDF probe at 36 degrees C induced a significant increase of FBP in all subjects (p < 0.001), but the slope of variation was significantly lower in patients with SSc compared to controls (p < 0.05). Patients with SSc showing the late NVC pattern of microangiopathy had significantly lower FBP than patients with the active and early NVC patterns (p < 0.05). A negative correlation was observed between FBP and NVC rating of the microvascular damage (p < 0.05). After iloprost treatment, a significant increase of FBP was observed in patients with SSc (p < 0.05).

CONCLUSION

Patients with SSc show a decreased FBP partially reversible by local skin heating. The FBP correlated negatively with the extent of nailfold microvascular damage, and IV iloprost treatment increased the FBP.

Cardiovascular autonomic neuropathy studied by a laser-Doppler blood flowmeter in hemodialysis patients

OBJECTIVE

Orthostatic hypotension during a hemodialysis (HD) session affects not only the modality but daily quality of life for HD patients because many of them have combined dysfunction of both sympathetic and parasympathetic nervous systems. Although various non-invasive methods have been applied for the evaluation of autonomic function, no monitor has been devised for measuring the dysfunction during blood purification therapy.

PATIENTS AND METHODS

We evaluated the usefulness of laser-Doppler blood flowmeter (LDF) for measuring autonomic function of stable 34 regular HD patients and 24 healthy controls. The LDF device was applied for autonomic test by measuring periflux blood flow decreasing velocity (PDV) accompanied with Valsalva maneuver. We also evaluated the correlation between PDV and conventional tests for atherosclerosis.

RESULTS

The average PDV (3.79±1.77) in HD population level was significantly lower than that of healthy controls (8.72±6.00). We also found a significant correlation between PDV and conventional methods such as heart rate variability and ankle-brachial blood pressure index.

CONCLUSION

Measurement of PDV by LDF is as useful as a conventional method for evaluating autonomic function in HD patients. The convenience of the device offers the benefit of daily and frequent measurement of autonomic dysfunction.