Moderate-dose atorvastatin improves arterial endothelial function in patients with angina pectoris and normal coronary angiogram: a pilot study

Genetic associations of cardiovascular risk genes in European patients with coronary artery spasm

BACKGROUND

Coronary artery spasm (CAS) is a frequent finding in patients presenting with angina pectoris. Although the pathogenesis of CAS is incompletely understood, previous studies suggested a genetic contribution. Our study aimed to elucidate genetic variants in a cohort of European patients with angina and unobstructed coronary arteries who underwent acetylcholine (ACh) provocation testing.

METHODS

A candidate association analysis of 208 genes previously associated with cardiovascular conditions was performed using genotyped and imputed variants in patients grouped in epicardial (focal, diffuse) CAS (n = 119) and microvascular CAS (n = 87). Patients with a negative ACh test result (n = 45) served as controls.

RESULTS

We found no association below the genome-wide significance threshold of p < 5 × 10-8, thus not confirming variants in ALDH2, NOS3, and ROCK2 previously reported in CAS patients of Asian ancestry. However, the analysis identified suggestive associations (p < 10-05) for the groups of focal epicardial CAS (CDH13) and diffuse epicardial CAS (HDAC9, EDN1). Downstream analysis of the potential EDN1 risk locus showed that CAS patients have significantly increased plasma endothelin-1 levels (ET-1) compared to controls. An EDN1 haplotype comprising rs9349379 and rs2070698 was significantly associated to ET-1 levels (p = 0.01).

CONCLUSIONS

In summary, we suggest EDN1 as potential genetic risk loci for patients with diffuse epicardial CAS, and European ancestry. Plasma ET-1 levels may serve as a potential cardiac marker.

The Importance of Integrated Regulation Mechanism of Coronary Microvascular Function for Maintaining the Stability of Coronary Microcirculation: An Easily Overlooked Perspective

Coronary microvascular dysfunction (CMD) refers to a group of disorders affecting the structure and function of coronary microcirculation and is associated with an increased risk of major adverse cardiovascular events. At present, great progress has been made in the diagnosis of CMD, but there is no specific treatment for it because of the complexity of CMD pathogenesis. Vascular dysfunction is one of the important causes of CMD, but previous reviews mostly considered microvascular dysfunction as a whole abnormality so the obtained conclusions are skewed. The coronary microvascular function is co-regulated by multiple mechanisms, and the mechanisms by which microvessels of different luminal diameters are regulated vary. The main purpose of this review is to revisit the mechanisms by which coronary microvessels at different diameters regulate coronary microcirculation through integrated sequential activation and briefly discuss the pathogenesis, diagnosis, and treatment progress of CMD from this perspective.

Updates on Pharmacologic Management of Microvascular Angina

Microvascular angina (MVA), historically called cardiac syndrome X, refers to angina with nonobstructive coronary artery disease. This female-predominant cardiovascular disorder adds considerable health-related costs due to repeated diagnostic angiography and frequent hospital admissions. Despite the high prevalence of this diagnosis in patients undergoing coronary angiography, it is still a therapeutic challenge for cardiologists. Unlike obstructive coronary artery disease, with multiple evidence-based therapies and management guidelines, little is known regarding the management of MVA. During the last decade, many therapeutic interventions have been suggested for the treatment of MVA. However, there is a lack of summarization tab and update of current knowledge about pharmacologic management of MVA, mostly due to unclear pathophysiology. In this article, we have reviewed the underlying mechanisms of MVA and the outcomes of various medications in patients with this disease. Contrary to vasospastic angina in which normal angiogram is observed as well, nitrates are not effective in the treatment of MVA. Beta-blockers and calcium channel blockers have the strongest evidence of improving the symptoms. Moreover, the use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, statins, estrogen, and novel antianginal drugs has had promising outcomes. Investigations are still ongoing for vitamin D, omega-3, incretins, and n-acetyl cysteine, which have resulted in beneficial initial outcomes. We believe that the employment of the available results and results of the future large-scale trials into cardiac care guidelines would help reduce the global cost of cardiac care tremendously.

Beneficial Effect of Statin Therapy on Arterial Stiffness

Arterial stiffness describes the increased rigidity of the arterial wall that occurs as a consequence of biological aging and several diseases. Numerous studies have demonstrated that parameters to assess arterial stiffness, especially pulse-wave velocity, are predictive of those individuals that will suffer cardiovascular morbidity and mortality. Statin therapy may be a pharmacological strategy to improve arterial elasticity. It has been shown that the positive benefits of statin therapy on cardiovascular disease is attributable not only to their lipid-lowering capacity but also to various pleiotropic effects, such as their anti-inflammatory, antiproliferative, antioxidant, and antithrombotic properties. Additionally, statins reduce endothelial dysfunction, improve vascular and myocardial remodeling, and stabilize atherosclerotic plaque. The aim of the present review was to summarize the evidence from human studies showing the effects of statins on arterial stiffness.

Standard exercise stress testing attenuates peripheral microvascular function in patients with suspected coronary microvascular dysfunction

BACKGROUND

The effect of exercise on the microvasculature of patients with suspected coronary microvascular dysfunction (CMD), assessed by reactive hyperemia peripheral arterial tonometry (RH-PAT; EndoPAT), is unknown. The present study aimed to determine if standard clinical exercise stress testing (GXT) affected peripheral microvascular function, as determined by the reactive hyperemia index (RHI and LnRHI), in patients with suspected CMD.

METHODS

In a cross-sectional study, patients (n = 76) were grouped based on whether the GXT was performed; 1) prior to (exercisers; n = 30), or 2) after the vascular assessment (non-exercisers; n = 46). Patients with an adenosine index of microvascular resistance > 25, adenosine coronary flow reserve (CFR) < 2.0, and/or acetylcholine CFR < 1.5 were considered to have CMD (n = 42). RHI and LnRHI quantified finger pulse amplitude hyperemia following 5 min of forearm ischemia.

RESULTS

LnRHI was lower in patients with CMD compared to patients without CMD, while LnRHI was also lower in exercisers compared to non-exercisers (LnRHI: CMD Non-Exercisers: 0.63 ± 0.25; CMD Exercisers: 0.54 ± 0.19; No CMD Non-Exercisers: 0.85 ± 0.23; No CMD Exercisers: 0.63 ± 0.26; Condition and Exercise Main Effects: Both P < 0.01). In patients who did not exercise prior to the vascular assessment, the receiver operating characteristic curve (ROC) for LnRHI to predict CMD was 0.76 (95% CI: 0.62-0.91; P < 0.01). However, in patients who performed exercise prior to the vascular assessment, the ROC for LnRHI to predict CMD was 0.60 (95% CI: 0.40-0.81; P = 0.34).

CONCLUSIONS

CMD is associated with impaired peripheral microvascular function and preceding acute exercise is associated with further reductions of LnRHI. Further, acute exercise abolished the capacity for RH-PAT to predict the presence of CMD in patients with chest pain and non-obstructive coronary arteries. RH-PAT measurements in patients with suspected CMD should not be conducted after exercise has been performed.

Low Levels of Low-Density Lipoprotein Cholesterol and Endothelial Function in Subjects without Lipid-Lowering Therapy

An elevation of serum low-density lipoprotein cholesterol (LDL-C) levels has been associated with endothelial dysfunction in statin naïve subjects. However, there is no information on endothelial function in subjects with extremely low levels of LDL-C. The purpose of the present study was to determine the relationship of LDL-C levels, especially low levels of LDL-C, with endothelial function. Endothelial function assessed by flow-mediated vasodilation (FMD) measurement and LDL-C levels were evaluated in 7120 subjects without lipid-lowering therapy. We divided the subjects into five groups by LDL-C levels: <70 mg/dL, 70-99 mg/dL, 100-119 md/dL, 120-139 mg/dL, and ≥140 mg/dL. FMD values were significantly smaller in subjects with LDL-C levels of ≥140 mg/dL than in those with LDL-C levels of 70-99 mg/dL and 100-119 mg/dL (p < 0.001 and p = 0.004, respectively). The FMD values in the LDL-C of <70 mg/dL group were not significantly different from those in the other groups. To evaluate the relationship of extremely low LDL-C levels with endothelial function, we divided the subjects with LDL-C of <70 mg/dL into those with LDL-C levels of <50 mg/dL and 50-69 mg/dL. FMD values were similar in the LDL-C <50 mg/dL group and ≥50 mg/dL group in the propensity score-matched population (p = 0.570). A significant benefit was not found in subjects with low LDL-C levels from the aspect of endothelial function.

Effects of Oral Drugs on Coronary Microvascular Function in Patients Without Significant Stenosis of Epicardial Coronary Arteries: A Systematic Review and Meta-Analysis of Coronary Flow Reserve

Objective: This study aims to investigate the impact of cardiovascular medications on the coronary flow reserve (CFR) in patients without obstructive coronary artery disease (CAD).

Methods: We searched PubMed, EMBASE, and Cochrane databases from inception to 15 November 2019. Studies were included if they reported CFR from baseline to follow-up after oral drug therapy of patients without obstructive CAD. Data was pooled using random-effects modeling. The primary outcome was change in CFR from baseline to follow-up after oral drug therapy.

Results: A total of 46 studies including 845 subjects were included in this study. Relative to baseline, the CFR was improved by angiotensin-converting enzymes (ACEIs), aldosterone receptor antagonists (ARBs) [standard mean difference (SMD): 1.12; 95% CI: 0.77–1.47], and statins treatments (SMD: 0.61; 95%CI: 0.36–0.85). Six to 12 months of calcium channel blocker (CCB) treatments improved CFR (SMD: 1.04; 95% CI: 0.51–1.58). Beta-blocker (SMD: 0.24; 95% CI: −0.39–0.88) and ranolazine treatment (SMD: 0.31; 95% CI: −0.39–1.01) were not associated with improved CFR.

Conclusions: Therapy with ACEIs, ARBs, and statins was associated with improved CFR in patients with confirmed or suspicious CMD. CCBs also improved CFR among patients followed for 6–12 months. Beta-blocker and ranolazine had no impact on CFR.

The Effect of Statins through Mast Cells in the Pathophysiology of Atherosclerosis: a Review

PURPOSE OF REVIEW

In this review, we discuss the evidence supporting the effects of statins on mast cells (MCs) in atherosclerosis and their molecular mechanism of action.

RECENT FINDINGS

Statins or HMG-CoA reductase inhibitors are known for their lipid-lowering properties and are widely used in the prevention and treatment of cardiovascular diseases. There is growing evidence that statins have an inhibitory effect on MCs, which contributes to the pleiotropic effect of statins in various diseases. MCs are one of the crucial effectors of the immune system which play an essential role in the pathogenesis of multiple disorders. Recent studies have shown that MCs are involved in the development of atherosclerotic plaques. MCs secrete various inflammatory cytokines (IL-6, IL4, TNF-α, and IFNγ) and inflammatory mediators (histamine, tryptase, proteoglycans) after activation by various stimulants. This, in turn, will exacerbate atherosclerosis. Statins suppress the activation of MCs via IgE inhibition which leads to inhibition of inflammatory mediators and cytokines which are involved in the development and progression of atherosclerosis. In keeping with this evidence presented here, MCs can be considered as one of the therapeutic targets for statins in the treatment of atherosclerosis.

Effects of Statin Treatment on Patients with Angina and Normal or Nearly Normal Angiograms

This article offers an updated and comprehensive overview of major findings on the effects of statin treatment in patients with chronic angina but without any epicardial coronary artery with obstructive lesion.

Noninvasive Microvascular Indices Reveal Peripheral Vascular Abnormalities in Patients With Suspected Coronary Microvascular Dysfunction

BACKGROUND

Reactive hyperemia peripheral arterial tonometry and flow-mediated dilation are common noninvasive measures of peripheral vascular function. However, their relationship with the coronary circulation, particularly in coronary microvascular dysfunction (CMD), is unclear. Therefore, the purpose of this study is to compare these noninvasive measurements with coronary microvascular function after endothelial-independent, endothelial-dependent, and sympathetically mediated pharmacologic hyperemia.

METHODS

Forty-seven patients with suspected CMD completed peripheral and coronary assessments. The reactive hyperemia index was collected using the EndoPAT2000 device, whereas a subset of patients (n = 28) completed brachial artery flow-mediated dilation using duplex ultrasound. Coronary microvascular function was quantified using the resistance and flow responses to intravenous adenosine (140 μg/kg/min), dobutamine (40 μg/kg/min), and intracoronary acetylcholine (100 μg). Abnormal coronary microvascular responses to adenosine and/or acetylcholine were used to define CMD.

RESULTS

The reactive hyperemia index (No CMD: 0.85 ± 0.23 vs CMD: 0.61 ± 0.26, P < 0.05) and flow-mediated dilation (No CMD: 7.2 ± 2.3 vs CMD: 4.8 ± 3.1; P < 0.05) were attenuated in patients with CMD. Whereas the reactive hyperemia index was correlated with the resistance and flow responses to dobutamine (ρ = -0.44 and ρ = 0.39, respectively; P < 0.05), flow-mediated dilation was correlated with the resistance responses to both adenosine (ρ = -0.48; P < 0.05) and acetylcholine (ρ = -0.66; P < 0.05). Lastly, the reactive hyperemia index and flow-mediated dilation had sensitivities of 80% and 69% and specificities of 71% and 93%, respectively, for identifying patients with CMD.

CONCLUSIONS

Peripheral vascular function is attenuated in CMD, and noninvasive measurements are associated with coronary responses to pharmaceutical stimulation.

Statin-Induced Nitric Oxide Signaling: Mechanisms and Therapeutic Implications

In addition to their cholesterol-lowering effects, statins are associated with pleiotropic effects including improvements in heart failure (HF), reduced blood pressure, prevention of the rupture of atherosclerotic plaques and improved angiogenesis. In addition to these cardiovascular benefits, statins have been implicated in the treatment of neurological injuries, cancer, sepsis, and cirrhosis. These cholesterol-independent beneficial effects of statins are predominantly mediated through signaling pathways leading to increased production and bioavailability of nitric oxide (NO). In this review, the mechanistic pathways and therapeutic effects of statin-mediated elevations of NO are described and discussed.

Arterial vessel reactivity in patients in the long term after kidney transplantation - preliminary study

INTRODUCTION

The aim of this study was to evaluate the endothelial-dependent and -independent arterial vessels' reactivity in patients in the long term after kidney transplantation (KTx).

MATERIAL AND METHODS

The study included 36 (15 females; 21 males) patients after KTx with good, stable graft function and 94 healthy individuals (51 males, 43 females). The endothelial-dependent dilatory capacity of the brachial artery was estimated by an ischemic test (flow-mediated dilation - FMD), and independent by nitroglycerin-mediated vasodilation (NMD). The results were shown for age-related groups and compared with age-related healthy people.

RESULTS

KTx patients were mean 5.1 ±2.3 years after transplantation with the mean estimated glomerular filtration rate (eGFR) 50.3 ±17.1 ml/min/1.73 m². The mean vessel diameter before tests was significantly larger in healthy people than in KTx patients. The FMD test showed vasodilation becoming weaker along with age in both groups, but in KTx patients this relationship was clearly enhanced. The NMD was delayed in relation to age, and in KTx patients was preserved, being only slightly weaker than in healthy people.

CONCLUSIONS

Both endothelium-dependent and -independent arterial wall reactions decrease with age. The endothelial-dependent vascular response is more attenuated in KTx patients than the independent one. The endothelium-independent vasodilation in KTx patients is comparable with that in healthy people.

Characterizing the relationship between flow-mediated vasodilation and radial artery tonometry in peripheral artery disease

BACKGROUND

Arterial stiffness, measured by the augmentation index (AIX) from radial artery tonometry, and endothelial dysfunction, measured by brachial-artery flow-mediated vasodilation (FMD), have each been associated with increased risk of cardiovascular events. However, their interrelationship in peripheral artery disease (PAD) patients is poorly understood.

MATERIALS AND METHODS

In a cross-sectional analysis of 123 vascular surgery outpatients, the association between FMD and AIX was examined in controls with atherosclerotic risk factors (n = 32) and patients with PAD (n = 91). PAD was defined as claudication symptoms with an ankle-brachial index of <0.9 or a history of revascularization for symptomatic PAD. Controls had an ankle-brachial index ≥0.9 and no history of atherosclerotic vascular disease.

RESULTS

Compared to controls, patients with PAD had lower FMD (6.3 ± 3.8 versus 8.4 ± 3.7, P = 0.008), while central AIX normalized to 75 beats per minute (25.5 ± 9.0 versus 19.3 ± 8.6, P = 0.001) and peripheral AIX (91.3 ± 14.5 versus 81.3 ± 11.4, P = 0.001) were higher. FMD was not significantly correlated with either central or peripheral AIX (central AIX: P = 0.58; peripheral AIX: P = 0.89) across the entire cohort, or in either the patients with PAD (central AIX: P = 0.48; peripheral AIX: P = 0.23) or controls (central AIX: P = 0.43; peripheral AIX: P = 0.92). In a multivariate model including FMD, higher AIX remained independently associated with PAD.

CONCLUSIONS

In an analysis of vascular surgery outpatients, no correlation between FMD and AIX was detected. Larger prospective studies are needed to determine whether the inclusion of both parameters improves predictive models for the early identification and potential risk stratification of PAD patients.

Pharmacologic Treatment of Patients With Myocardial Ischemia With No Obstructive Coronary Artery Disease

Half of women and 1/3 of men with angina and ischemia on stress testing have ischemia with no obstructive coronary artery disease (INOCA). These patients have quality of life (QoL) impairment comparable with patients with obstructive coronary artery disease. Clinicians generally treat INOCA with traditional antianginal agents despite previous studies demonstrating variable response to these medications. We performed a systematic review to evaluate the efficacy and safety of available pharmacologic therapies for INOCA. We systematically searched the Cochrane Central Register of Controlled Trials, Embase, MEDLINE, and the World Health Organization International Clinical Trials Registry Platform in July 2017 for randomized controlled trials (RCTs) evaluating pharmacologic agents for INOCA. The primary outcome of interest was QoL. Secondary outcomes included subjective and objective efficacy measures and safety outcomes. We included 35 RCTs from 333 identified studies. Interventions that improved QoL with moderate-quality evidence included angiotensin-converting enzyme (ACE) inhibitor (±statin) and ranolazine. Low-to-very-low-quality evidence also suggests that ACE inhibitors, β blockers, calcium-channel blockers, nicorandil, ranolazine, and statins may decrease angina frequency and delay ischemia on stress testing. Other interventions, most notably nitrates, did not significantly improve any outcome. In conclusion, evidence for pharmacologic treatment of INOCA is generally poor, and higher-quality RCTs using a standardized definition of INOCA are needed. Moderate-quality evidence suggests that ACE inhibitors and ranolazine improve QoL. Other interventions had low-quality evidence or no evidence of efficacy.

Monotherapy of experimental metabolic syndrome: I. Efficacy and safety

Elevated plasma cholesterol, especially low density lipoprotein (LDL) cholesterol, is one of the major risk factors for atherosclerosis and coronary heart disease. Hereditary hypertriglyceridemic rats (hHTG) were developed as a new inbred model for the study of relationships between blood pressure and metabolic abnormalities. The aim of this work was to determine the cholesterol-lowering and antioxidant effects of the novel pyridoindol derivative SMe1EC2, compared to the cholesterol-lowering drug atorvastatin, in rats fed either standard or high-fat and high-cholesterol diet (HFC; 1% cholesterol and 7.5% lard fat). Male hHTG rats fed HFC (HTG+HFC) were administered with SMe1EC2 or atorvastatin (both 50 mg/kg/day p.o.) for 4 weeks. Physiological status of animals was monitored by the measurement of preprandial glucose levels and blood pressure. Lipid profile was characterized by the serum levels of total cholesterol (TC), HDL-, LDL-cholesterol and triglycerides (TRG). The concentration of thiobarbituric acid reactive substances (TBARS) was evaluated in the kidney, liver and serum. Further, the assessment of pro-inflammatory cytokines TNF-α, IL-1 and IL-6 in the serum was completed. Feeding the animals with HFC diet resulted in increased serum levels of TC, LDL and TRG. SMe1EC2 ameliorated serum levels of LDL in hHTG rats, both on standard and HFC diet. These effects were comparable with those of the standard hypolipidemicum atorvastatin. SMe1EC2 lowered blood pressure, tissue TBARS concentrations and serum IL-1 levels of HTG+HFC rats. Beneficial effects together with very good toxicity profile predestinate SMe1EC2 to be promising agent for further surveys related to metabolic syndrome features.