Lack of seasonal variation in flow-mediated dilatation of the brachial artery in women with primary Raynaud's phenomenon and healthy controls

Seasonal variations in endothelium-dependent flow-mediated vasodilation and endothelium-independent nitroglycerine-induced vasodilation

Cardiovascular mortality has been shown to vary seasonally. However, it has not been determined whether vascular function is affected by the season. The purpose of this study was to investigate the associations of vascular function with season and outdoor temperature. Between April 2007 and March 2022, measurements of flow-mediated vasodilation (FMD) of the brachial artery as an index of endothelial function and nitroglycerine-induced vasodilation (NID) as an index of endothelium-independent vasodilation were performed in 2190 subjects. There was no significant seasonal difference in FMD (spring, 3.9 ± 3.1%; summer, 3.5 ± 3.0%; fall, 3.7 ± 3.0%; winter, 3.6 ± 3.2%; P = 0.14). There was no significant correlation between FMD and daily mean outdoor temperature (r = -0.02, P = 0.25). Multivariate analyses revealed that neither season (β = -0.020, P = 0.31) nor outdoor temperature (β = 0.005, P = 0.81) was significantly associated with FMD after adjustment for other confounding factors. There were significant seasonal differences in NID (spring, 12.8 ± 6.3%; summer, 12.0 ± 6.1%; fall, 11.7 ± 6.1%; winter, 12.3 ± 5.9%; P = 0.02). However, multivariate analysis revealed that there was no significant association between season and NID after adjustment for other confounding factors (β = -0.012, P = 0.56). There was no significant correlation between NID and daily outdoor mean temperature (r = -0.03, P = 0.17). Multivariate analysis revealed that outdoor temperature was not significantly associated with NID (β = -0.006, P = 0.78). There was no significant association of FMD or NID with season or outdoor temperature, suggesting that it is not necessary to take into account the effects of season and outdoor temperature on vascular function when interpreting the results of FMD and NID measurements. Public trials registry number: UMIN000039512.

The Association of Flow-Mediated Dilatation and Blood Parameters in Primary Raynaud's Phenomenon

INTRODUCTION

Raynaud's phenomenon (RP) is a multifactorial disorder. If any underlying disease cannot be determined to be responsible for RP, then it is considered to be the primary RP (pRP). We aimed to investigate the differences between laboratory markers and impaired endothelial function in pRP.

MATERIALS AND METHODS

Forty-two pRP patients and 30 healthy individuals were included as the study and control groups, respectively. The endothelial function was evaluated with flow-mediated dilatation (FMD) of the brachial artery. The blood samples were obtained from both groups, and white blood cell (WBC), hemoglobin, platelets, mean platelet volume (MPV), creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), D-dimer, fibrinogen, albumin, fibrinogen-to-albumin ratio (FAR), neutrophil-to-lymphocyte ratio (NLR), D-dimer-to-albumin ratio (DDAR), and monocyte chemoattractant protein-1 (MCP-1) parameters were studied. The blood parameters and FMD values obtained were compared between groups.

RESULTS

The groups were similar in regard to age, gender, and smoking history (p < 0.05). There was no difference between the two groups in regard to hemoglobin, platelet, MPV, creatinine, ALT, D-dimer, albumin, FAR, NLR, and DDAR levels (p < 0.05). AST levels were slightly higher in the pRP group (p=0.027). Markedly increased WBC, fibrinogen, MPV, and MCP-1 values were detected in the pRP group (p=0.001), as well as higher abnormal FMD responses (p=0.001). There was a direct correlation between abnormal FMD response and serum MCP-1 values in patients with pRP (R: 0.308, R ²: 0.095, p: 0.044).

CONCLUSION

It seems to be that MCP-1 levels are higher in patients with pRP, and increased values of MCP-1 levels seem to be related to impaired endothelial functions.

Endothelial function in response to exercise in the cold in patients with coronary artery disease

BACKGROUND

Regular long-term physical exercise has favourable effects on endothelial function in patients with coronary artery disease (CAD). However, the effects of an acute exercise bout in the cold on endothelial function are not known.

METHODS

At first, the effects of moderate-intensity aerobic lower-body exercise were assessed in CAD patients (n = 16) in a neutral [+22°C] and cold [-15°C] environment. Secondly, responses to static and dynamic upper-body exercise in a neutral [+22°C] and cold [-15°C] environment were investigated in CAD patients (n = 15). All experiments were performed in a random order. Endothelial function was measured by flow-mediated dilation (FMD) of the brachial artery in response to reactive hyperaemia, before and after the exposures in a neutral environment.

RESULTS

No significant temperature*exercise*condition (pre-post) interaction was observed in FMD% when comparing rest versus aerobic exercise or static versus dynamic upper-body exercise. Relative reactive hyperaemia during FMD protocol, measured by changes in shear rate, was elevated after rest compared to aerobic exercise (p = .001) and after static compared to dynamic upper-body exercise (p < .001). However, no significant temperature*exercise*condition interaction was observed when FMD% was normalized for shear rate.

CONCLUSIONS

Endothelial function to an acute bout of exercise among CAD patients was not modified by the environmental temperature where the exercise was performed. The present findings argue against the hypothesis that exercise in cold environmental conditions impairs endothelial function in patients with CAD.

Seasonal variation in critical limb ischemia requiring endovascular therapy: an analysis of a multicenter database of Japanese patients with critical limb ischemia undergoing endovascular therapy

AIM

We investigated whether any seasonal variation is observed in the incidence, severity and prognosis of critical limb ischemia (CLI) requiring endovascular therapy.

METHODS

We analyzed a multicenter database of 1,568 consecutive CLI cases undergoing primary endovascular therapy for infrainguinal lesions between July 2004 and June 2011. The monthly incidence was assessed according to the cumulative number of cases in each month, using a simple moving average. The data were fitted to a nonlinear regression model with a cosine function. The monthly proportion of cases in each Rutherford classification among the overall CLI population was assessed using a multinomial logistic regression model. The monthly risk of major amputation was evaluated using a Cox proportional hazard regression model.

RESULTS

Significant seasonal variation was observed in the incidence of CLI (p＜0.01). It was higher in the period from winter to spring, with a peak in March, and lower in the period from summer to autumn, with a trough in September; the fold difference between the peak and trough was 2.2. The seasonal variation was more markedly observed in the cases with a more severe Rutherford class. The proportion of cases in each Rutherford class among the overall CLI population also exhibited significant seasonal variation (p＜0.01). In addition, the risk of major amputation demonstrated significant seasonal variation (p=0.03); however, the statistical significance was lost following adjustment for the Rutherford classification (p=0.10).

CONCLUSIONS

Seasonal variation is observed in the incidence and severity of CLI. The seasonality of the limb prognosis is likely explained by that of the CLI severity.

Auricular electroacupuncture reduces frequency and severity of Raynaud attacks

BACKGROUND

Acupuncture has been shown to influence skin perfusion and the subjective cold perception threshold. Therefore, we hypothesized that auricular electroacupuncture (EA) might reduce symptoms in primary Raynaud's phenomenon (PRP).

METHODS

Twenty-six patients with PRP received 6 cycles of auricular EA. After 3, 6 and 24 weeks attack frequency and severity were reevaluated using standardized questionnaires and a visual analogue scale (VAS). Skin temperature was assessed by infrared thermography and laser Doppler perfusion imaging was used to determine skin perfusion.

RESULTS

Compared to baseline we found a significant reduction of attack frequency after 3 (p = 0.001) and 6 weeks (p < 0.001) of auricular EA. This improvement sustained following cessation of EA, after 24 weeks (p < 0.001). Furthermore, attack associated pain was reduced after 3 (p = 0.003), 6 (p = 0.003) and 24 weeks (p = 0.001) of treatment, while skin temperature and skin perfusion did not change significantly throughout the study period.

CONCLUSIONS

Auricular EA reduces symptoms by means of frequency and severity of attacks in PRP but has no influence on skin perfusion and skin temperature.

Relation of season and temperature to endothelium-dependent flow-mediated vasodilation in subjects without clinical evidence of cardiovascular disease (from the Framingham Heart Study)

Multiple studies have documented an increased incidence of cardiovascular events in the winter, but the pathophysiologic mechanisms remain incompletely understood. It was hypothesized that brachial flow and flow-mediated dilation (FMD) would vary by season and temperature. Season and temperature were related to ultrasonic brachial artery endothelium-dependent FMD% (n = 2,587), baseline flow velocity, and maximal reactive hyperemia (n = 1,973) in the Framingham Offspring Cohort (mean age 61 +/- 10 years, 53% women). Outdoor temperatures were obtained from National Climate Data Center records for Bedford, Massachusetts (about 14 miles from the testing site), and the examination room temperature was measured. In multivariate models, FMD% was highest in summer and lowest in winter (3.01 +/- 0.09% vs 2.56 +/- 0.10%, respectively, p = 0.02 for differences across all 4 seasons). FMD% was highest in the warmest and lowest in the coldest outdoor-temperature quartiles. In stepwise models adjusting for risk factors and selecting among season, outdoor temperature, and room temperature, FMD% was associated with season (p = 0.02); temperature did not enter the model. In contrast, hyperemic flow velocity was significantly lower for cooler and higher for warmer room temperatures (p = 0.02 overall); season did not enter the model. Season and outdoor and room temperature were each retained in a stepwise model of baseline flow velocity (p <0.0001, p = 0.02, and p <0.0001, respectively). In conclusion, a significant association was observed between season and FMD%. Microvascular vasodilator function, as reflected by hyperemic flow velocity, was more strongly related to temperature than season. Endothelial dysfunction may be 1 of the mechanisms influencing seasonal variation in cardiovascular events.

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

Background Patients with systemic sclerosis (SSc) frequently suffer from recalcitrant digital ulceration because of impaired cutaneous blood flow (CBF). A simple and accurate CBF measurement would be helpful to evaluate the disease status and efficacy of treatment in such patients. Objectives To examine the feasibility of a newly developed, micromachined integrated laser blood flowmeter (MILBF) for evaluation of abnormal CBF responses in patients with SSc. Methods CBF of finger pulp was measured in eight patients with SSc and in six healthy controls using MILBF. CBF in the steady state and the responses to the arm-raising test and cold provocation were assessed. The therapeutic efficacy of a single and an intensive prostaglandin E(1) (PGE(1)) infusion treatment was also evaluated in some of the SSc patients. Results The patients with SSc showed significantly lower steady-state CBF than controls. The rate of blood flow with cold provocation and the velocity of blood flow recovery after cold provocation (VR-CP) tended to be lower in patients with SSc. Augmentation of amplitude of the digital pulse wave by arm raising (AA-AR) was observed in controls, but not in patients with SSc. We also found that VR-CP and AA-AR may be good markers for evaluating the efficacy of vasodilatory treatment. It should be noted that the examined patients did not complain of any pain and/or distress during the arm-raising test, as opposed to during cold provocation. Conclusions CBF assessment using MILBF and an arm-raising test is accurate, noninvasive and well tolerated and thus the combination may be a better alternative method to evaluate abnormal CBF and efficacy of treatment in patients with SSc.