Microvascular Reactivity in Response to Smoking and Oral Antioxidants in Humans

Smoking and Respiratory Diseases in Patients with Coronary Microvascular Dysfunction

BACKGROUND

Coronary microvascular disease (CMD) is common in patients with and without obstructive coronary artery disease, and is associated with adverse clinical outcomes. Respiratory-related variables are associated with pulmonary and systemic microvascular dysfunction, while evidence about their relationship with CMD is limited. We aim to evaluate respiratory-related variables as risk factors of CMD.

METHODS

This is an observational, single-center study enrolling consecutive patients undergoing invasive evaluation of coronary microvascular function in the catheterization laboratory. Patients with evidence of obstructive coronary artery disease or with missing data were excluded. Associations between respiratory-related variables and indices of CMD were assessed using univariate and multivariate regression models.

RESULTS

Overall, 266 patients (mean age 67 ± 11 years, 59% females) were included in the current analysis. Of those, 155 (58%) had evidence of CMD. Among the respiratory variables, independent predictors of CMD were current smoking (adjusted odds ratio [AOR] 2.5; 95% confidence interval [CI], 1.2-5; P = .01) and obstructive sleep apnea (AOR 5.7; 95% CI, 1.2-26; P = .03), while chronic obstructive pulmonary disease was not. Among ever-smokers, higher smoking pack-years was an independent risk factor for CMD (median 35 vs 25 pack-years, AOR 1.09; 95% CI, 1.04-1.13; P < .01), and was associated with higher rates of pathologic index of microcirculatory resistance and resistive reserve ratio.

CONCLUSION

In patients undergoing invasive coronary microvascular evaluation, current smoking and obstructive sleep apnea are independently associated with CMD. Among smokers, higher pack-years is a strong predictor for CMD. Our findings should raise awareness for prevention and possible treatment options.

Quantitative nailfold capillaroscopy-update and possible next steps

We review the exciting potential (and challenges) of quantitative nailfold capillaroscopy, focusing on its role in systemic sclerosis. Quantifying abnormality, including automated analysis of nailfold images, overcomes the subjectivity of qualitative/descriptive image interpretation. First we consider the rationale for quantitative analysis, including the potential for precise discrimination between normal and abnormal capillaries and for reliable measurement of disease progression and treatment response. We discuss nailfold image acquisition and interpretation, and describe how early work on semi-quantitative and quantitative analysis paved the way for semi-automated and automated analysis. Measurement of red blood cell velocity is described briefly. Finally we give a personal view on 'next steps'. From a clinical perspective, increased uptake of nailfold capillaroscopy by general rheumatologists could be achieved via low-cost hand-held devices with cloud-based automated analysis. From a research perspective, automated analysis could facilitate large-scale prospective studies using capillaroscopic parameters as possible biomarkers of systemic sclerosis-spectrum disorders.

Microvascular capillary assessment in relation to forearm blood flow

OBJECTIVE

To study whether vascular reactivity as assessed by the methods forearm blood flow (FBF) and postocclusive reactive hyperaemia (PRH) in the nail fold was related as a measure of endothelium-dependent vasodilation in the microcirculation.

METHODS

Microvascular reactivity was assessed in forearm blood flow and in the nail fold by vital capillaroscopy of individual microvessels as postocclusive reactive hyperaemia. Vascular reactivity was assessed at baseline (n = 25) as well as after infusion of acetylcholine and of sodium nitroprusside (n = 13). We also performed a multivariate regression analysis to assess whether forearm blood flow or flow-mediated dilatation related to postocclusive reactive hyperaemia.

RESULTS

This study showed a distinct microvascular response to both acetylcholine (endothelium-dependent vasodilation) and sodium nitroprusside (endothelium-independent vasodilation) during forearm blood flow assessment and postocclusive reactive hyperaemia assessment in the nail fold (n = 13). These changes were inversely related (r- = -0·57; P<0·05).

CONCLUSIONS

Forearm blood flow was inversely correlated to postocclusive reactive hyperaemia. Postocclusive reactive hyperaemia was shortened after infusion with both acetylcholine and sodium nitroprusside. This occurred in parallel with the expected increase in forearm blood flow, conceivably reflecting that both methods can be used to assess endothelium-dependent vasodilation in the microcirculation.

Permanence of Modifications in Oral Microcirculation in Ex-Smokers

Background

The aim of this study was to assess the long-term effects of smoking and to investigate the permanence of this damage to the oral microcirculation.

Material/Methods

We recruited 75 patients and divided them into 3 groups: group 1 was composed of 25 healthy non-smokers, group 2 was composed of 25 healthy current smokers, and group 3 was composed of 25 healthy ex-smokers. Video-capillaroscopic examination was performed on all patients.

The video-capillaroscopic investigation was performed on patients in sitting position, always with the same light source, at the same room temperature (23°C), in the morning, with the same operator (GAS), and was repeated many times for every area under investigation. An enlargement of 200× allowed us to explore point-by-point all the morpho-structural characteristics of the capillaroscopic field. For non-parametric data, we evaluated the visibility of the loops and their position in relation to the surface of the mucosa. The evaluated parametric data were length of capillary loop, diameter of the loop, capillary tortuosity, and capillary density.

Results

Our study clearly shows there was no remission of vascular damage, even 13 years after smoking cessation.

Conclusions

Our research shows that that the effects of smoking are still visible in ex-smokers, even at 13 years after cessation and also that ex-smokers are still subject to the risk of oral pathologies in the interval of time that we considered.

Automated structure and flow measurement - a promising tool in nailfold capillaroscopy

OBJECTIVES

Despite increasing interest in nailfold capillaroscopy, objective measures of capillary structure and blood flow have been little studied. We aimed to test the hypothesis that structural measurements, capillary flow, and a combined measure have the predictive power to separate patients with systemic sclerosis (SSc) from those with primary Raynaud's phenomenon (PRP) and healthy controls (HC).

METHODS

50 patients with SSc, 12 with PRP, and 50 HC were imaged using a novel capillaroscopy system that generates high-quality nailfold images and provides fully-automated measurements of capillary structure and blood flow (capillary density, mean width, maximum width, shape score, derangement and mean flow velocity). Population statistics summarise the differences between the three groups. Areas under ROC curves (A_Z) were used to measure classification accuracy when assigning individuals to SSc and HC/PRP groups.

RESULTS

Statistically significant differences in group means were found between patients with SSc and both HC and patients with PRP, for all measurements, e.g. mean width (μm) ± SE: 15.0 ± 0.71, 12.7 ± 0.74 and 11.8 ± 0.23 for SSc, PRP and HC respectively. Combining the five structural measurements gave better classification (A_Z = 0.919 ± 0.026) than the best single measurement (mean width, A_Z = 0.874 ± 0.043), whilst adding flow further improved classification (A_Z = 0.930 ± 0.024).

CONCLUSIONS

Structural and blood flow measurements are both able to distinguish patients with SSc from those with PRP/HC. Importantly, these hold promise as clinical trial outcome measures for treatments aimed at improving finger blood flow or microvascular remodelling.

[Periungueal capillaroscopy: an easy and reliable method to evaluate all microcirculation diseases]

Periungueal capillaroscopy is a simple and reliable non-invasive technique allowing evaluation of cutaneous microcirculation. It was promoted for decades in patients with Raynaud's phenomenon in order to differentiate between the benign primary Raynaud's phenomenon and the secondary form in connective tissue diseases, especially systemic sclerosis. Nevertheless, the value of this procedure has also been shown in numerous pathologies such as diabetes or cardiovascular diseases. This literature review points to the versatility of this useful exam and its results in a large spectrum of diseases with microvascular involvement.

Associations Between Dietary Patterns and Skin Microcirculation in Healthy Subjects

Objective—

Microvascular dysfunction is suggested to be a marker of common pathophysiological mechanisms in the development of insulin resistance, cardiovascular diseases, and type 2 diabetes mellitus. Given the established relationship of diet with the macrovascular disease, the aim of this study was to investigate for the first time the possible associations between dietary patterns and microcirculation.

Approach and Results—

Two hundred ninety-one healthy men and women selected from the Supplementation en Vitamines et Mineraux Antioxydants 2’ cohort were assessed for anthropometric, nutritional, biochemical, and microcirculation parameters using finger skin capillaroscopy. Dietary intake was assessed cross-sectionally using a food frequency questionnaire, and principal component analysis was used to identify dietary patterns from 40 food groups. Six dietary patterns were identified. A dietary pattern characterized by increased consumption of vegetable oils, poultry, and fish and seafood was positively associated with both functional and anatomic capillary density after adjusting for confounders ( β =0.13, P =0.05 and β= 0.20, P= 0.00, respectively). A second dietary pattern with increased consumption of sweets was inversely associated with functional and anatomic capillary density in all multivariate models ( β =−0.14, P =0.03 and β= −0.17, P= 0.01). There were no associations between any of the derived dietary patterns and capillary recruitment.

Conclusions—

In healthy subjects, a dietary pattern characterized by an increased consumption of vegetable oils, poultry, and fish and seafood and low consumption of sweets was associated with better microvascular function. Further prospective studies are needed to confirm the present association.

Spotlight issue: Microcirculation—from a clinical perspective

This spotlight issue of Microcirculation contains five articles written from a clinical perspective on the role of microcirculatory abnormalities in the pathogenesis of cardiovascular disease. The reviews address issues such as the impact of modifiable (life style and environmental risk factors) and non modifiable (age) on microvascular form and function; inter- and intra-cell signaling pathways underlying microvascular dysfunction; microvascular assessment as a prognostic tool in clinical practice; and the potential impact of targeted therapeutic intervention on microvascular health. The articles also describe and evaluate methodological approaches to the assessment of microvascular function in organs such as the skin, retina, muscle and adipose tissue, and provide a perspective on how such approaches might be employed in future in disease risk stratification in large epidemiological studies. This timely edition of the journal Microcirculation highlights that while there is currently no identified unifying mechanism to explain the association between microvascular phenotype and susceptibility to disease, there is accumulating evidence that deficits in microvascular structure and function may be an early and important prodromal indicator and risk determinant in a wide range of chronic non-communicable disorders, including cardiovascular and metabolic disease.