Vascular Function and Intima-media Thickness of a Leg Artery in Peripheral Artery Disease: A Comparison of Buerger Disease and Atherosclerotic Peripheral Artery Disease

A Nomogram for Predicting the Risk of Critical Limb Ischemia in Adults with Hypertension: A Retrospective Study

Purpose

Peripheral arterial disease (PAD) presenting with underlying hypertension (HTN) poses a higher risk of bilateral lower limb amputation than PAD patients without HTN. While the role of HTN management of PAD patients has received limited attention. We analyzed the clinical characteristics of PAD in adults with HTN and explored risk factors for PAD to construct a nomogram for evaluating critical limb ischemia (CLI) and lesion severity.

Methods Patients and Methods

Between January 2014 and December 2019, we retrospectively evaluated 1886 patients with peripheral artery disease with coexisting HTN. Patients were randomly divided into training (n = 1320, 70%) and validation cohorts (n = 566, 30%), and according to the subjective experience of PAD [Fontaine classification (I-II vs III-IV)], patients were further classified into intermittent claudication (IC) and CLI groups. LASSO regression and multivariate Cox proportional hazard analyses were used to construct a nomogram using variables defined in the training cohort, which was validated in the validation cohort. The evaluation of the predictive discriminative, accuracy and clinical application are further analyzed.

Results

In the training cohort, optimal independent factors included age, male sex, body mass index, diabetes mellitus, heart rate, triglyceride, and uric acid (AM-BDHTU), which were included in the nomogram predicting the CLI risk (all P < 0.05). The C-index values for CLI risk in PAD with HTN patients were 0.729 (95% CI: 0.704-0.807) and 0.728 (95% CI: 0.652-0.744) in the training and validation sets, respectively. Calibration curves indicated good consistency between predicted and actual outcomes. DCA confirmed the clinical utility of the diagnostic model.

Conclusion

The AM-BDHTU nomogram, constructed and validated using simple to obtain clinical variables, when combined with the Fontaine classification, effectively predicts the risk of CLI among PAD patients with HTN.

Detrimental effects of physical inactivity on peripheral and brain vasculature in humans: Insights into mechanisms, long-term health consequences and protective strategies

The growing prevalence of physical inactivity in the population highlights the urgent need for a more comprehensive understanding of how sedentary behaviour affects health, the mechanisms involved and what strategies are effective in counteracting its negative effects. Physical inactivity is an independent risk factor for different pathologies including atherosclerosis, hypertension and cardiovascular disease. It is known to progressively lead to reduced life expectancy and quality of life, and it is the fourth leading risk factor for mortality worldwide. Recent evidence indicates that uninterrupted prolonged sitting and short-term inactivity periods impair endothelial function (measured by flow-mediated dilation) and induce arterial structural alterations, predominantly in the lower body vasculature. Similar effects may occur in the cerebral vasculature, with recent evidence showing impairments in cerebral blood flow following prolonged sitting. The precise molecular and physiological mechanisms underlying inactivity-induced vascular dysfunction in humans are yet to be fully established, although evidence to date indicates that it may involve modulation of shear stress, inflammatory and vascular biomarkers. Despite the steady increase in sedentarism in our societies, only a few intervention strategies have been investigated for their efficacy in counteracting the associated vascular impairments. The current review provides a comprehensive overview of the evidence linking acute and short-term physical inactivity to detrimental effects on peripheral, central and cerebral vascular health in humans. We further examine the underlying molecular and physiological mechanisms and attempt to link these to long-term consequences for cardiovascular health. Finally, we summarize and discuss the efficacy of lifestyle interventions in offsetting the negative consequences of physical inactivity.

Integration of traditional Chinese medicine and nibble debridement and dressing method reduces thrombosis and inflammatory response in the treatment of thromboangiitis obliterans

Background

Thromboangiitis obliterans (TAO), also known as Buerger's disease, is an occlusive arterial disease; however, the pathogenesis of TAO is still unclear. Research has shown that traditional Chinese medicine (TCM) has significant advantages in the treatment of TAO. Our purpose was to explore the underlying roles of TCM in combination with nibble debridement and dressing method (NDDM) in a TAO rat model.

Methods

We administered rats with 10 mg/mL sodium laurate to establish a TAO model, and then the TAO model rats were treated with notoginseng powder (NP), maifusheng (MFS), or the combination of NP or MFS and NDDM. Gangrene classification and blood rheology were evaluated; the pathological characteristics of rat limbs were examined by hematoxylin and eosin (H&E) staining and Masson staining; and cluster of differentiation 3+ (CD3+) and cluster of differentiation 20+ (CD20+) levels were measured by immunohistochemistry (IHC) and flow cytometry. In addition, inflammation-associated cytokines were analyzed by quantitative reverse transcription polymerase chain reaction (RT-qPCR), western blot, and enzyme-linked immunosorbent assay (ELISA).

Results

Integration of NP or MFS and NDDM dramatically reduced the gangrene classification and affected blood rheology parameters of TAO model rats compared with NP and MFS alone. Meanwhile, NP or MFS in combination with NDDM decreased CD3+CD20+ T cells, reduced thrombosis and inflammatory cell infiltration, and dramatically decreased the levels of inflammation-associated cytokines.

Conclusions

Our results suggested that integration of NP or MFS and NDDM could relieve the symptoms of TAO model rats induced by sodium laurate, which might provide a new management strategy for TAO.

Disparities in Peripheral Artery Disease Hospitalizations Identified Among Understudied Race-Ethnicity Groups

Background: To assess racial/ethnic differences in disease severity, hospital outcomes, length of stay and healthcare costs among hospitalized patients with peripheral artery disease (PAD).

Methods: This study used data from the National Inpatient Sample (NIS) to explore the racial/ethnic disparities in PAD-related hospitalizations including presence of PAD with chronic limb threatened ischemia (CLI), amputation, in-hospital mortality, length of hospital stays and estimated medical costs. Race-ethnicity groups included non-Hispanic White, Black, Hispanic, Asian or Pacific Islander, Native American, and others (multiple races). Regression analyses adjusted for age, gender, Charlson Comorbidity Index, primary payer, patient location, bed size of the admission hospital, geographic region of the hospital, and rural/urban location of the hospital.

Results: A total of 341,480 PAD hospitalizations were identified. Compared with non-Hispanic Whites, Native Americans had the highest odds of PAD with CLI (OR = 1.77, 95% CI: 1.61, 1.95); Black (OR = 1.71, 95% CI: 1.66, 1.76) and Hispanic (OR = 1.36, 95% CI: 1.31,1.41) patients had higher odds of amputation; Asian or Pacific Islanders had a higher mortality (OR = 1.20, 95% CI: 1.01,1.43), whereas Black (OR = 0.81, 95% CI: 0.76, 0.87) patients has a lower mortality; Asian or Pacific Islanders incurred higher overall inpatient costs (Margin = 30093.01, 95% CI: 28827.55, 31358.48) and most prolonged length of stay (IRR = 0.14, 95% CI: 0.09, 0.18).

Conclusions: Our study identified elevated odds of amputation among Hispanic patients hospitalized with PAD as well as higher hospital mortality and medical expenses among Asian or Pacific Islander PAD inpatients. These two demographic groups were previously thought to have a lower risk for PAD and represent important populations for further investigation.

Diagnostic Criteria of Flow-Mediated Vasodilation for Normal Endothelial Function and Nitroglycerin-Induced Vasodilation for Normal Vascular Smooth Muscle Function of the Brachial Artery

Background

Diagnostic criteria of flow‐mediated vasodilation (FMD), an index of endothelial function, and nitroglycerin‐induced vasodilation (NID), an index of vascular smooth muscle function, of the brachial artery have not been established. The purpose of this study was to propose diagnostic criteria of FMD and NID for normal endothelial function and normal vascular smooth muscle function.

Methods and Results

We investigated the cutoff values of FMD and NID in subjects with (risk group) and those without cardiovascular risk factors or cardiovascular diseases (no‐risk group) in 7277 Japanese subjects (mean age 51.4±10.8 years) from the Flow‐Mediated Dilation Japan study and the Flow‐Mediated Dilatation Japan Registry study for analysis of the cutoff value of FMD and in 1764 Japanese subjects (62.2±16.1 years) from the registry of Hiroshima University Hospital for analysis of the cutoff value of NID. Receiver‐operator characteristic curve analysis of FMD to discriminate subjects in the no‐risk group from patients in the risk group showed that the optimal cutoff value of FMD to diagnose subjects in the no‐risk group was 7.1%. Receiver‐operator characteristic curve analysis of NID to discriminate subjects in the no‐risk group from patients in the risk group showed that the optimal cutoff value of NID to diagnose subjects in the no‐risk group was 15.6%.

Conclusions

We propose that the cutoff value for normal endothelial function assessed by FMD of the brachial artery is 7.1% and that the cutoff value for normal vascular smooth muscle function assessed by NID of the brachial artery is 15.6% in Japanese subjects.

Clinical Trial Registration

http://www.umin.ac.jp Unique identifiers: UMIN000012950, UMIN000012951, UMIN000012952, and UMIN000003409

Assessment of endothelium-independent vasodilation: from methodology to clinical perspectives

: Vascular response to exogenously administered nitroglycerine, an index of endothelium-independent vasodilation, has been used as a control test for the assessment of endothelium-dependent vasodilation (endothelial function) in humans. However, evidence has been accumulating that not only endothelium-dependent vasodilation but also endothelium-independent vasodilation per se is impaired in individuals with cardiovascular risk factors and cardiovascular disease. Impaired endothelium-independent vasodilation is associated with structural vascular alterations and alterations in vascular smooth muscle cells. Several methods, including assessment of vascular responses to vasoactive agents using angiography in a coronary artery and vascular responses to vasoactive agents using venous occlusion plethysmography and ultrasonography in a peripheral artery, are used to assess endothelium-independent vasodilation in humans. Measurement of endothelium-independent vasodilation is also useful for assessment of atherosclerosis and may be a predictor of future cardiovascular events. In this review, we focus on assessment of endothelium-independent vasodilation from methodology aspects to clinical perspectives.

Daily Passive Muscle Stretching Improves Flow-Mediated Dilation of Popliteal Artery and 6-minute Walk Test in Elderly Patients with Stable Symptomatic Peripheral Artery Disease

BACKGROUND

Patients with peripheral arterial disease (PAD) often have walking impairment due to insufficient oxygen supply to skeletal muscle. In aged rats, we have shown that daily stretching of calf muscles improves endothelium-dependent dilation of arterioles from the soleus muscle and increases capillarity and muscle blood flow during exercise. Therefore, we hypothesized that daily muscle stretching of calf muscles would improve endothelium-dependent vasodilation of the popliteal artery and walking function in PAD patients.

METHODS

We performed a randomized, non-blinded, crossover study whereby 13 patients with stable symptomatic PAD were randomized to undergo either 4 weeks of passive calf muscle stretching (ankle dorsiflexion applied 30 min/d, 5 days/wk) followed by 4 weeks of no muscle stretching and vice versa. Endothelium-dependent flow-mediated dilation (FMD) and endothelium-independent nitroglycerin-induced dilation of the popliteal artery and 6 minute walk test (6MWT) were evaluated at baseline and after each 4 week interval.

RESULTS

After 4 weeks of muscle stretching, FMD and 6MWT improved significantly in the muscle stretching group vs. the control (FMD: 5.1 ± 0.5% vs. 3.7 ± 0.3%, P = 0.005; 6MWT continuous walking distance: 304 ± 43 m vs. 182 ± 34 m; P = 0.0006). No difference in nitroglycerin-induced dilation was found between groups (10.9 ± 1.2 vs. 9.9 ± 0.4%, P = 0.48). Post-stretching, 6MWT total walking distance was positively correlated with normalized FMD (R = 0.645, P = 0.02).

CONCLUSIONS

Passive calf muscle stretching enhanced vascular endothelial function and improved walking function in elderly patients with stable symptomatic PAD. These findings merit further investigation in a prospective randomized trial.

Flow Mediated Dilatation as a Biomarker in Vascular Surgery Research

Endothelial dysfunction is one of the hallmarks of atherogenesis, and correlates with many cardiovascular risk factors. One of the features of endothelial dysfunction is the loss of nitric oxide (NO) bioavailability, resulting in derangements in the vasodilatory response of the vessel wall. Flow mediated dilatation (FMD) of the brachial artery is an accepted method for non-invasive assessment of systemic endothelial function. FMD is examined extensively in the context of cardiovascular research, and has been utilised as a routine assessment in large cohorts such as the Framingham Heart Study, Young Finns Study, and Gutenberg Heart Study. However, FMD is less known in the context of vascular surgery research, despite the similarities between the underpinning disease mechanisms. This review will provide a summary of FMD in terms of its history of development and the conduct of the test in research settings. It will further highlight the key literature of FMD as a biomarker for vascular surgeons, particularly in the context of abdominal aortic aneurysms and lower limb peripheral arterial disease.

Asymptomatic Plaques of Lower Peripheral Arteries and Their Association with Cardiovascular Disease: An Autopsy Study

Aims: Patients with peripheral artery disease (PAD) have a high prevalence of cardiovascular morbidity and mortality; however, majority of patients with PAD are asymptomatic. This study aimed to histologically evaluate whether asymptomatic, lower extremity artery plaques are associated with systemic atherosclerosis and the onset of cardiovascular disease (CVD) events using autopsy cases.

Methods: We histologically investigated the atherosclerotic plaques of the common iliac, common carotid, coronary, and renal arteries from 121 autopsy cases without symptoms of PAD (mean age: 67.6 years; 63% men; 83% non-CVD death). We evaluated the relationship between the degree of iliac artery atherosclerosis and that of other arteries, and also the presence of any CVD, myocardial infarction, stroke, and renal failure.

Results: Advanced atherosclerotic plaques (American Heart Association ≥ 4) were present in 86 (72%) common iliac arteries in these cases. These arteries also showed high frequencies of calcification (66%), intraplaque hemorrhage (42%), and plaque disruption (24%). These advanced lesions were associated with age (≥ 60 years), sex (male), hypertension, diabetes, and smoking habit (all P < 0.05). Additionally, it was significantly associated with CVD (odds ratio, 95% confidence interval; 6.2, 2.2–22), myocardial infarction (6.4, 1.2– 19), stroke (8.7, 1.7 –16), and renal failure/hemodialysis (5.8, 1.1 – 11). Cases with advanced iliac artery plaques had advanced coronary and carotid atherosclerosis.

Conclusion: These results indicate that asymptomatic advanced plaques are frequently observed in common iliac arteries, and are associated with generalized atherosclerosis and CVD events.