Night-time blood pressure variability negatively correlated with reactive hyperemia index

Systemic Endothelial Function, Plasma Xanthine Oxidoreductase Activity, and Blood Pressure Variability in Patients with Stable Coronary Artery Disease

Background and Objectives: Although previous studies showed that an activity of xanthine oxidoreductase (XOR), a rate-limiting enzyme in purine metabolism, beyond the serum uric acid level, was associated with the development of coronary artery disease (CAD), the underlying mechanisms are unclear. Because endothelial dysfunction and a greater blood pressure (BP) variability may play a role, we investigated the relations among the endothelial function, XOR, and BP variability. Materials and Methods: This was a post-hoc study using pooled data of patients with a stable CAD from two prospective investigations, in which the systemic endothelial function was assessed with the reactive hyperemia index (RHI) and the XOR activity was measured. The BP variability was evaluated using BP measurements during the three- and four-day hospitalization. Results: A total of 106 patients with a stable CAD undergoing a percutaneous coronary intervention were included. Of the 106 patients, 46 (43.4%) had a systemic endothelial dysfunction (RHI < 1.67). The multivariable analysis identified a higher body mass index (BMI), female gender, and diabetes as factors associated with an endothelial dysfunction. A higher BMI was also related to an elevated XOR activity, in addition to current smoking. No significant correlation was observed between the RHI and XOR activity. Similarly, the in-hospital BP variability was associated with neither the endothelial function nor XOR. Conclusions: Among patients with a stable CAD, several factors were identified as being associated with a systemic endothelial dysfunction or an elevated XOR activity. However, no direct relations between the endothelial function, XOR, and BP variability were found.

Recent Advances in Non-Invasive Blood Pressure Monitoring and Prediction Using a Machine Learning Approach

Blood pressure (BP) monitoring can be performed either invasively via arterial catheterization or non-invasively through a cuff sphygmomanometer. However, for conscious individuals, traditional cuff-based BP monitoring devices are often uncomfortable, intermittent, and impractical for frequent measurements. Continuous and non-invasive BP (NIBP) monitoring is currently gaining attention in the human health monitoring area due to its promising potentials in assessing the health status of an individual, enabled by machine learning (ML), for various purposes such as early prediction of disease and intervention treatment. This review presents the development of a non-invasive BP measuring tool called sphygmomanometer in brief, summarizes state-of-the-art NIBP sensors, and identifies extended works on continuous NIBP monitoring using commercial devices. Moreover, the NIBP predictive techniques including pulse arrival time, pulse transit time, pulse wave velocity, and ML are elaborated on the basis of bio-signals acquisition from these sensors. Additionally, the different BP values (systolic BP, diastolic BP, mean arterial pressure) of the various ML models adopted in several reported studies are compared in terms of the international validation standards developed by the Advancement of Medical Instrumentation (AAMI) and the British Hypertension Society (BHS) for clinically-approved BP monitors. Finally, several challenges and possible solutions for the implementation and realization of continuous NIBP technology are addressed.

Impact of Serum Uric Acid Level on Systemic Endothelial Dysfunction in Patients with a Broad Spectrum of Ischemic Heart Disease

Previous studies indicated that serum uric acid (SUA) level is a marker of endothelial function in subsets of ischemic heart disease (IHD). In the present study, we aimed to evaluate the relation between the SUA level and endothelial function in patients with a broad spectrum of IHD, including obstructive coronary artery disease (CAD) and ischemia with no obstructive CAD (INOCA). Three prospective studies and one retrospective study were pooled, in which the SUA level was measured, and systemic endothelial function was assessed using the reactive hyperemia index (RHI). The primary endpoint of the present study was a correlation of the SUA level with RHI. A total of 181 patients with a broad spectrum of IHD were included, among whom, 46 (25%) had acute coronary syndrome presentation and 15 (8%) had INOCA. Overall, the SUA level was negatively correlated with the RHI (r = −0.22, p = 0.003). Multivariable analysis identified the SUA level and INOCA as significant factors associated with RHI values. In conclusion, in patients with a broad spectrum of IHD, including obstructive epicardial CAD (chronic and acute coronary syndromes) and INOCA, the SUA level was significantly and negatively correlated with systemic endothelial function assessed with the RHI. INOCA, rather than obstructive CAD, was more associated with endothelial dysfunction.

Impact of glycemic variability on coronary and peripheral endothelial dysfunction in patients with coronary artery disease

BACKGROUND

Previous studies have reported that glucose variability leads to endothelial dysfunction and progression of coronary atherosclerosis. However, few studies have directly evaluated the relation between glucose variability and coronary endothelial function in patients with coronary artery disease (CAD).

METHODS

A total of 38 patients with chronic CAD and a history of coronary drug-eluting stent implantation were enroled. Coronary endothelial function was evaluated by measuring the coronary vasoreactivity using quantitative coronary angiography in the segment distal to implanted stent in response to intracoronary acetylcholine (ACh) infusion (10-7 mol/l). Peripheral endothelial function was also assessed with reactive hyperemia index (RHI). The mean amplitude of glycemic excursion (MAGE) was calculated as a primary metric of glucose variability using a flash glucose monitoring system.

RESULTS

Of 38 patients, 17 (45%) had diabetes mellitus. The mean levels of glycated hemoglobin, MAGE, and RHI were 6.3 ± 0.8%, 71.4 ± 29.8 mg/dl, and 1.85 ± 0.63. In the distal segment to coronary stent, lumen diameter was constricted by 0.6 ± 7.3% in response to intracoronary ACh infusion compared to that at baseline. While peripheral endothelial function assessed with RHI was not significantly associated with MAGE (r = -0.16, p = 0.35), coronary endothelial function was correlated with MAGE (r = -0.38, p = 0.02).

CONCLUSION

Greater glucose variability was significantly associated with coronary rather than peripheral endothelial dysfunction in patients with CAD, suggesting an impact of glucose variability on coronary atherosclerosis.

Association between lipid profile and endothelial dysfunction as assessed by the reactive hyperemia index

INTRODUCTION

We investigated the associations between endothelial dysfunction (ED) as evaluated by the reactive hyperemia index (RHI) obtained using Endo-PAT2000® and atherosclerotic risk factors in patients who underwent coronary artery angiography (CAG).

METHODS

The subjects consisted of 191 patients who were clinically suspected to have CAD and underwent CAG, and in whom we could perform Endo-PAT2000®. We divided the patients into ED (RHI<1.67, n = 71) and non-ED (RHI≥1.67, n = 120) groups.

RESULTS

The ED group was significantly older and showed a higher ratio of low-density lipoprotein cholesterol (LDL-C) to high-density lipoprotein cholesterol (HDL-C) (L/H) than the non-ED group. A multivariate logistic regression analysis was performed to examine the associations between the presence of ED and age, gender, and BMI in addition to L/H. Age [odds ratio (OR) = 1.03, p = .02] and L/H (OR = 1.64, p = .01) were identified as significant independent markers of the presence of ED. Next, we divided 122 patients with statin treatment into ED (n = 40) and non-ED (n = 82) groups. The ED group tended to have higher L/H and lower HDL-C than the non-ED group. HDL-C (OR = 0.95, p = .01) and age (OR = 1.05, p = .04) were identified as independent markers of the presence of ED.

CONCLUSIONS

L/H was an independent marker of the presence of ED in patients without dyslipidemia. In addition, among patients with statin treatment, HDL-C was an independent marker of the presence of ED.

Peripheral arterial endothelial dysfunction predicts future cardiovascular events in diabetic patients with albuminuria: a prospective cohort study

Background

Reactive hyperemia-peripheral arterial tonometry (RH-PAT) is a noninvasive and simple test for evaluating the endothelial function. There has been sparse evidence on the usefulness of the RH-PAT index (RHI) in predicting future cardiovascular diseases among diabetic patients.

Methods

Asymptomatic diabetic patients with albuminuria were selected; their medical history and laboratory findings were evaluated every 3 to 4 months, respectively. The primary outcome was a composite of three-point major adverse cardiovascular events (3-point MACE): death from cardiovascular causes, acute coronary events, or nonfatal stroke. On the contrary, secondary outcomes included a composite of 3-point MACE, hospitalization for heart failure, or chronic kidney disease (CKD) progression. RHI was measured using the Endo-PAT2000 at the baseline. RHI < 1.67 was considered to indicate peripheral endothelial dysfunction (PED).

Results

In total, 149 subjects were included (mean age, 61.8 ± 9.2 years; duration of diabetes was 12 years). During the follow-up period (median, 49.7 months), of the 149 subjects, primary outcomes were detected in 12 (1 [2.3%] and 11 [10.5%] of those without and with PED, respectively). The presence of PED in baseline measurements significantly increased both primary and secondary outcomes, following adjustment for age, sex, hypertension, glycated hemoglobin, low-density lipoprotein cholesterol, triglyceride, systolic blood pressure, baseline estimated glomerular filtration rate, overt proteinuria, duration of diabetes, premedical history of ischemic events, anti-platelet agents, and smoking history (hazard ratio [HR]: 10.95; 95% confidence interval CI 1.00–119.91 for the primary outcome; HR, 4.12; 95% CI 1.37–12.41 for secondary outcome). In addition, PED could predict secondary outcomes independent of the risk score according to the American College of Cardiology/American Heart Association (HR: 3.24; 95% CI 1.14–9.17).

Conclusions

PED can independently predict future cardiovascular events among diabetic patients with albuminuria.

Reactive Hyperemia Index Associated With Atherosclerotic Cardiovascular Disease Under Treatment for Lifestyle Diseases

Background

Endothelial dysfunction is an early phase of atherosclerosis and causes atherosclerotic cardiovascular disease (ASCVD), but the cutoff reactive hyperemia index (RHI) for identifying ASCVD patients under treatment for lifestyle diseases is unknown.

Methods

Patients who visited Cardiology Section, Izumi General Medical Center, Kagoshima, Japan and were measured RHI using Endo-PAT 2000 during May 2014 and March 2016 were enrolled. We divided them into ASCVD and non-ASCVD groups and investigated the association with RHI between the groups.

Results

ASCVD group included 195 patients and non-ASCVD group included 288 patients. Age, body mass index and the rate of male, hypertension, diabetes, dyslipidemia and chronic kidney disease in the ASCVD group were significantly higher than those in non-ASCVD group. RHI in the ASCVD group (1.65 (1.40 - 1.92)) was significantly lower than that in the non-ASCVD group (1.73 (1.45 - 2.24)) (P < 0.05). In multi-regression analysis, RHI (odds ratio: 0.67, 95% confidence interval: 0.45 - 0.99, P = 0.04) was independently associated with ASCVD after adjusted by age, sex, body mass index, smoking, hypertension, diabetes, dyslipidemia and chronic kidney disease. The cutoff RHI value between the groups was 1.80.

Conclusion

RHI was significantly associated with ASCVD under treatment for lifestyle diseases and the cutoff value was 1.80.

Relation of Elevated Serum Uric Acid Level to Endothelial Dysfunction in Patients with Acute Coronary Syndrome

Aim: Serum uric acid (SUA) level is known to have a prognostic value in patients with acute coronary syndrome (ACS). Endothelial function plays an important role in the development of cardiovascular disease. Although relation between SUA level and endothelial function has been previously studied in various populations, it is partially understood in patients with ACS.

Methods: A total of 55 patients with ACS with measurements of SUA level and reactive hyperemia index (RHI) to evaluate endothelial function were included. They were classified into three groups according to the tertiles of SUA level. The tertiles of SUA level were as follows: low tertile, ≤ 5.2 mg/dl; intermediate tertile, 5.3 to 6.5 mg/dl; and high tertile, ≥ 6.6 mg/dl.

Results: Mean SUA level and RHI were 5.8 ± 1.5 mg/dl and 1.88 ± 0.58. There was a significant negative correlation between SUA level and RHI (r = −0.41, p = 0.002). RHI was stepwisely observed in favor of the higher tertile groups (2.14 ± 0.74 vs. 1.84 ± 0.45 vs. 1.67 ± 0.38, p = 0.04). Multivariate analysis showed elevated SUA level as an independent predictor of reduced RHI.

Conclusion: Elevated SUA level was significantly associated with endothelial dysfunction in patients with ACS, possibly leading to subsequent poor outcomes following ACS.