Clinical assessment of endothelial function in heart failure with preserved ejection fraction: A meta-analysis with meta-regressions

Impact of Acute Antioxidant and Tetrahydrobiopterin (BH4) Administration on Locomotor Muscle Microvascular Function in Patients With Heart Failure

BACKGROUND

Peripheral microvascular dysfunction is a hallmark feature of both heart failure with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF) pathophysiology, due partly to impairments in nitric oxide signaling secondary to tetrahydrobiopterin (BH4) deficiency and oxidative stress.

METHODS

Using a randomized, double-blind, placebo-controlled crossover design, this study examined the impact of enteral BH4 (10 mg/kg), an antioxidant cocktail (AOx), and coadministration of these 2 agents (BH4+AOx) on microvascular function in patients with HFrEF (n=14, 64±10 years) and HFpEF (n=19, 74±9 years). Passive limb movement was utilized to assess locomotor muscle microvascular function, and biomarkers of inflammation and oxidative damage were measured.

RESULTS

Compared with placebo, the peak change in leg blood flow was not statistically different after AOx administration (HFrEF, P=0.60; HFpEF, P=0.61), but improved following BH4 (P=0.033) and BH4+AOx (P=0.019) in both HFrEF (placebo: 234±31; BH4: 357±45; BH4+AOx: 355±49 mL/min) and HFpEF (placebo: 269±33; BH4: 367±47; BH4+AOx: 394±65 mL/min). The total hyperemic response to passive limb movement (leg blood flow area under the curve) was not statistically different across treatments in patients with HFrEF (P=0.29), but increased following BH4 (P=0.016) and BH4+AOx (P=0.040) in the HFpEF group. CRP (C-reactive protein) was lower following BH4 (P=0.007) and BH4+AOx (P=0.007) in HFpEF (placebo: 4268±547; BH4: 2721±391; BH4+AOx: 2779±376 ng/mL), but was not statistically different in HFrEF (P=0.39).

CONCLUSIONS

Together, these results provide new evidence for the efficacy of acute BH4 administration to improve some aspects of locomotor muscle microvascular function in patients with HFrEF and HFpEF, with no apparent benefit of AOx administration, alone or in combination with BH4, in either group. These findings lend further conceptual support for the nitric oxide pathway as a modifiable target in the treatment of heart failure.

Blood pressure behavior during exercise in patients with diastolic dysfunction and a hypertensive response to exercise

A hypertensive response to exercise is a precursor leading to hypertension, which is a major risk factor for the development of heart failure and diastolic dysfunction. Herein, we aimed to assess blood pressure (BP) in patients with a hypertensive response to exercise and different degrees of diastolic dysfunction. Between January 2009 and December 2014, 373 patients with a hypertensive response to exercise (HRE) and echocardiographic data assessing diastolic function were enrolled at the University Hospital of Zurich. ANCOVA was used to assess the changes in BP response during exercise testing in individuals with different degrees of diastolic dysfunction. Normalization of systolic BP was blunted in patients with grade II and III diastolic dysfunction after 3 min of recovery in univariable [β (95%) - 9.2 (-13.8 to - 4.8) p < .001, -16.0 (-23.0 to 9.0) p < .001, respectively] and adjusted models. In fully adjusted models, when taking maximal effort into account, there were no differences with regard to systolic BP during exercise. Patients without diastolic dysfunction achieved higher heart rates (HRs) [both in absolute terms (p < .001) and as a percentage of the calculated maximum (p = .003)] and greater wattage (p < .001) at maximum exertion. The findings of this cross-sectional study suggest that exercise capacity is compromised in patients with diastolic dysfunction. A hypertensive response to exercise and the finding of a blunted BP recovery may help identify patients at risk of developing heart failure.

Statin administration improves vascular function in heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is characterized by impaired vascular endothelial function that may be improved by hydroxy-methylglutaryl-CoA (HMG-CoA) reductase enzyme inhibition. Thus, using a parallel, double-blind, placebo-controlled design, this study evaluated the efficacy of 30-day atorvastatin administration (10 mg daily) on peripheral vascular function and biomarkers of inflammation and oxidative stress in 16 patients with HFpEF [Statin: n = 8, 74 ± 6 yr, ejection fraction (EF) 52-73%; Placebo: n = 8, 67 ± 9 yr, EF 56-72%]. Flow-mediated dilation (FMD) and sustained-stimulus FMD (SS-FMD) during handgrip (HG) exercise, reactive hyperemia (RH), and blood flow during HG exercise were evaluated to assess conduit vessel function, microvascular function, and exercising muscle blood flow, respectively. FMD improved following statin administration (pre, 3.33 ± 2.13%; post, 5.23 ± 1.35%; P < 0.01), but was unchanged in the placebo group. Likewise, SS-FMD, quantified using the slope of changes in brachial artery diameter in response to increases in shear rate, improved following statin administration (pre: 5.31e-5 ± 3.85e-5 mm/s-1; post: 8.54e-5 ± 4.98e-5 mm/s-1; P = 0.03), with no change in the placebo group. Reactive hyperemia and exercise hyperemia responses were unchanged in both statin and placebo groups. Statin administration decreased markers of lipid peroxidation (malondialdehyde, MDA) (pre, 0.652 ± 0.095; post, 0.501 ± 0.094; P = 0.04), whereas other inflammatory and oxidative stress biomarkers were unchanged. Together, these data provide new evidence for the efficacy of low-dose statin administration to improve brachial artery endothelium-dependent vasodilation, but not microvascular function or exercising limb blood flow, in patients with HFpEF, which may be due in part to reductions in oxidative stress.NEW & NOTEWORTHY This is the first study to investigate the impact of statin administration on vascular function and exercise hyperemia in patients with heart failure with preserved ejection fraction (HFpEF). In support of our hypothesis, both conventional flow-mediated dilation (FMD) testing and brachial artery vasodilation in response to sustained elevations in shear rate during handgrip exercise increased significantly in patients with HFpEF following statin administration, beneficial effects that were accompanied by a decrease in biomarkers of oxidative damage. However, contrary to our hypothesis, reactive hyperemia and exercise hyperemia were unchanged in patients with HFpEF following statin therapy. These data provide new evidence for the efficacy of low-dose statin administration to improve brachial artery endothelium-dependent vasodilation, but not microvascular reactivity or exercising muscle blood flow in patients with HFpEF, which may be due in part to reductions in oxidative stress.

Exercise intolerance in heart failure with preserved ejection fraction: Causes, consequences and the journey towards a cure

Heart failure with preserved ejection fraction (HFpEF) accounts for over 50% of all heart failure cases nationwide and continues to rise in its prevalence. The complex, multi-organ involvement of the HFpEF clinical syndrome requires clinicians and investigators to adopt an integrative approach that considers the contribution of both cardiac and non-cardiac function to HFpEF pathophysiology. Thus, this symposium review outlines the key points from presentations covering the contributions of disease-related changes in cardiac function, arterial stiffness, peripheral vascular function, and oxygen delivery and utilization to exercise tolerance in patients with HFpEF. While many aspects of HFpEF pathophysiology remain poorly understood, there is accumulating evidence for a decline in vascular health in this patient group that may be remediable through pharmacological and lifestyle interventions and could improve outcomes and clinical status in this ever-growing patient population.

Exercise may not just be good for sleep; It can also help lower cardiovascular event risk

Cardiovascular diseases (CVD) stand at the forefront of global mortality, presenting an immense and urgent public health challenge on a global scale. Effectively addressing the associated risk factors is pivotal in not only preventing but also stabilizing and potentially reversing the progression of these conditions. Emerging research illuminates a compelling correlation between sleep disorders and CVD. Clinically, individuals afflicted with existing CVD or those possessing risk factors frequently grapple with sleep disturbances, exacerbating their conditions, particularly in severe cases where disease progression is accelerated. Even among ostensibly healthy individuals, chronic sleep deprivation exacts a toll on cardiovascular function. The strategic implementation of exercise interventions emerges as a potent tool in enhancing sleep quality, surpassing the efficacy of pharmaceutical treatments. Furthermore, the maintenance of optimal sleep patterns significantly contributes to lowering the risk of cardiovascular diseases. This comprehensive review delves deeply into the intricate relationship between exercise and the amelioration of cardiovascular disease risk associated with sleep. Moreover, it meticulously elucidates the complex mechanisms through which exercise operates, effectively reducing cardiovascular disease risk from the unique perspective of sleep science.

Endothelial Dysfunction and Heart Failure with Preserved Ejection Fraction-An Updated Review of the Literature

Heart failure (HF) is a clinical syndrome consisting of typical symptoms and signs due to structural and/or functional abnormalities of the heart, resulting in elevated intracardiac pressures and/or inadequate cardiac output. The vascular system plays a crucial role in the development and progression of HF regardless of ejection fraction, with endothelial dysfunction (ED) as one of the principal features of HF. The main ED manifestations (i.e., impaired endothelium-dependent vasodilation, increased oxidative stress, chronic inflammation, leukocyte adhesion, and endothelial cell senescence) affect the systemic and pulmonary haemodynamic and the renal and coronary circulation. The present review is aimed to discuss the contribution of ED to HF pathophysiology-in particular, HF with preserved ejection fraction-ED role in HF patients, and the possible effects of pharmacological and non-pharmacological approaches. For this purpose, relevant data from a literature search (PubMed, Scopus, EMBASE, and Medline) were reviewed. As a result, ED, assessed via venous occlusion plethysmography or flow-mediated dilation, was shown to be independently associated with poor outcomes in HF patients (e.g., mortality, cardiovascular events, and hospitalization due to worsening HF). In addition, SGLT2 inhibitors, endothelin antagonists, endothelial nitric oxide synthase cofactors, antioxidants, and exercise training were shown to positively modulate ED in HF. Despite the need for future research to better clarify the role of the vascular endothelium in HF, ED represents an interesting and promising potential therapeutic target.

Maximal Exercise Improves the Levels of Endothelial Progenitor Cells in Heart Failure Patients

The impact of exercise on the levels of endothelial progenitor cells (EPCs), a marker of endothelial repair and angiogenesis, and circulating endothelial cells (CECs), an indicator of endothelial damage, in heart failure patients is largely unknown. This study aims to evaluate the effects of a single exercise bout on the circulating levels of EPCs and CECs in heart failure patients. Thirteen patients with heart failure underwent a symptom-limited maximal cardiopulmonary exercise test to assess exercise capacity. Before and after exercise testing, blood samples were collected to quantify EPCs and CECs by flow cytometry. The circulating levels of both cells were also compared to the resting levels of 13 volunteers (age-matched group). The maximal exercise bout increased the levels of EPCs by 0.5% [95% Confidence Interval, 0.07 to 0.93%], from 4.2 × 10−3 ± 1.5 × 10−3% to 4.7 × 10−3 ± 1.8 × 10−3% (p = 0.02). No changes were observed in the levels of CECs. At baseline, HF patients presented reduced levels of EPCs compared to the age-matched group (p = 0.03), but the exercise bout enhanced circulating EPCs to a level comparable to the age-matched group (4.7 × 10−3 ± 1.8 × 10−3% vs. 5.4 × 10−3 ± 1.7 × 10−3%, respectively, p = 0.14). An acute bout of exercise improves the potential of endothelial repair and angiogenesis capacity by increasing the circulating levels of EPCs in patients with heart failure.

Improved vascular function and functional capacity following l-citrulline administration in patients with heart failure with preserved ejection fraction: a single-arm, open-label, prospective pilot study

There is accumulating evidence for both peripheral vascular dysfunction and impaired functional capacity in patients with heart failure with a preserved ejection fraction (HFpEF). Although derangements in the l-arginine-nitric oxide (l-Arg-NO) pathway are likely to contribute to these aspects of HFpEF pathophysiology, the impact of increased NO substrate on vascular health and physical capacity has not been evaluated in this patient population. Thus, using a single-arm study design, we evaluated the impact of enteral l-citrulline (l-Cit, 6 g/day for 7 days), a precursor for l-Arg biosynthesis, on vascular function [flow-mediated dilation (FMD), reactive hyperemia (RH), and passive limb movement (PLM)], functional capacity [6-min walk test (6MWT)], and biomarkers of l-Arg-NO signaling in 14 patients with HFpEF (n = 14, 4 M/10 F, 70 ± 10 yr, EF: 66 ± 7%). Compared with baseline (0d), 7 days of l-Cit administration improved FMD (0d: 2.5 ± 1.6%, 7d: 4.5 ± 2.9%), RH (0d: 468 ± 167 mL, 7d: 577 ± 199 mL), PLM blood flow area-under-the-curve (0d: 139 ± 130 mL, 7d: 198 ± 115 mL), and 6MWT distance (0d: 377 ± 27 m, 7d: 397 ± 27 m) (P < 0.05). An increase in plasma l-Cit (0d: 42 ± 11 µM/L, 7d: 369 ± 201 µM/L), l-Arg (0d: 65 ± 8 µM/L, 7d: 257 ± 25 µM/L), and the ratio of l-Arg to asymmetric dimethylarginine (ADMA) (0d: 136 ± 13 AU, 7d: 481 ± 49 AU) (P < 0.05) was also observed. Though preliminary in nature, these functional and biomarker assessments demonstrate a potential benefit of l-Cit administration in patients with HFpEF, findings that provide new insight into the mechanisms that govern vascular and physical dysfunction in this patient group.NEW & NOTEWORTHY The current investigation has demonstrated that l-Cit administration may improve brachial artery endothelium-dependent vasodilation, upper and lower limb microvascular function, and physical capacity in patients with HFpEF, highlighting the potential therapeutic potential of interventions targeting the l-Arg-NO signaling cascade to improve outcomes in this patient group.

The impact of periodontitis on vascular endothelial dysfunction

Periodontitis, an oral inflammatory disease, originates from periodontal microbiota dysbiosis which is associated with the dysregulation of host immunoinflammatory response. This chronic infection is not only harmful to oral health but is also a risk factor for the onset and progress of various vascular diseases, such as hypertension, atherosclerosis, and coronary arterial disease. Vascular endothelial dysfunction is the initial key pathological feature of vascular diseases. Clarifying the association between periodontitis and vascular endothelial dysfunction is undoubtedly a key breakthrough for understanding the potential relationship between periodontitis and vascular diseases. However, there is currently a lack of an updated review of their relationship. Therefore, we aim to focus on the implications of periodontitis in vascular endothelial dysfunction in this review.

Cardio-Ankle Vascular Index and Heart Failure Hospitalization in Patients With Aortic Stenosis Following Transcatheter Aortic Valve Implantation

Background: The cardio-ankle vascular index (CAVI) is associated with the severity of vascular stiffness and heart failure (HF). However, little is known about CAVI in aortic stenosis (AS) patients, probably because of the difficulty of accurately measuring CAVI in these patients owing to their slow-rising pulse. In this study, we investigated the prevalence and prognostic impact of abnormally elevated CAVI measured after transcatheter aortic valve implantation (TAVI).

Methods and Results: Among patients with AS who underwent TAVI, those with bilateral peripheral artery disease, atrial fibrillation, and systolic HF were excluded. The effect of post-TAVI elevated CAVI (defined as ≥9.0) on HF readmission after the index discharge was investigated. In all, 149 patients (mean [±SD] age 84.8±5.6 years, 24.2% men, mean [±SD] post-TAVI CAVI 9.6±1.4) were included in the study. There was no significant difference in baseline characteristics between groups with and without elevated CAVI, except for lower high-density lipoprotein cholesterol (HDL-C) and a higher prevalence of HF history in the group with elevated CAVI (P<0.05 for both). Post-TAVI elevated CAVI (n=102) was associated with lower freedom from HF recurrence during the observational period (89.1% vs. 100%; median 726 days [interquartile range 329–1,104 days]; P<0.05). Moreover, CAVI was an independent predictor of HF occurrence (hazard ratio 1.62; 95% confidence interval 1.07–2.46; P=0.022).

Conclusions: Elevated CAVI was associated with HF occurrence before and after TAVI.

Biphasic Effects of Blue Light Irradiation on Human Umbilical Vein Endothelial Cells

Blue light regulates biological function in various cells, such as proliferation, oxidative stress, and cell death. We employed blue light illumination on human umbilical vein endothelial cells utilizing a LED device at 453 nm wavelength and revealed a novel biphasic response on human umbilical vein endothelial cells (HUVECs). The results showed that low fluence blue light irradiation promoted the fundamental cell activities, including cell viability, migration and angiogenesis by activating the angiogenic pathways such as the VEGF signaling pathway. In contrast, high fluence illumination caused the opposite effect on those activities by upregulating pro-apoptotic signaling cascades like ferroptosis, necroptosis and the p53 signaling pathways. Our results provide an underlying insight into photobiomodulation by blue light and may help to implement potential treatment strategies for treating angiogenesis-dependent diseases.

Clinical Assessment of Endothelial Function in Convalescent COVID-19 Patients Undergoing Multidisciplinary Pulmonary Rehabilitation

Background: Growing evidence points to a key role of endothelial dysfunction in the pathogenesis of COVID-19. In this study, we evaluated changes in endothelium-dependent flow-mediated dilation (FMD) in a cohort of convalescent COVID-19 patients undergoing pulmonary rehabilitation (PR). Methods: After swab test negativization, convalescent COVID-19 patients referring to a post-acute care facility for PR were consecutively screened for inclusion. Study procedures were performed at the time of hospitalization and discharge. Results: We enrolled 82 convalescent COVID-19 patients (85.4% males, mean age 60.4 years). After PR, a significant improvement in most pulmonary function tests and exercise capacity was documented. FMD changed from 2.48% ± 2.01 to 4.24% ± 2.81 (p < 0.001), corresponding to a 70.9% increase. Significantly higher changes in FMD were found in patients without a history of vascular events as compared to those with (+2.04% ± 2.30 vs. +0.61% ± 1.83, p = 0.013). Values of forced expiratory volume in 1 s (FEV₁%), forced vital capacity (FVC%) and diffusion capacity for carbon monoxide (DLCO%) significantly and directly correlated with FMD both at baseline and after PR. Patients with normal FEV₁% (≥80% predicted) during the overall study period or those normalizing FEV₁% after PR showed a more significant FMD change as compared to patients with persistently impaired FEV₁% (<80% predicted) (p for trend = 0.029). This finding was confirmed in a multivariate analysis. Conclusions: Clinically evaluated endothelial function improves after PR in convalescent COVID-19 patients. A direct and persistent association between the severity of pulmonary and vascular disease can be hypothesized. Endothelial function testing may be useful in the follow-up of convalescent COVID-19 patients.