Association of beta-blocker use with increased aortic wave reflection

PCSK9 inhibitors ameliorate arterial stiffness in ACS patients: evidences from Mendelian randomization, a retrospective study and basic experiments

Background

Current evidences suggest that Proprotein Convertase Subtilisin/kexin Type 9 inhibitors (PCSK9i) exhibit a protective influence on acute coronary syndrome (ACS). Nevertheless, further investigation is required to comprehend the impact and mechanisms of these pharmaceutical agents on inflammatory factors and arterial stiffness (AS) in patients with ACS. Consequently, the objective of this study is to ascertain the influence of PCSK9i on arterial stiffness in ACS patients and elucidate the underlying mechanisms behind their actions.

Methods

This study employed Mendelian randomization (MR) analysis to examine the association between genetic prediction of PCSK9 inhibition and arterial stiffness. Data of 71 patients with ACS were retrospectively collected, including PCSK9i group (n = 36, PCSK9 inhibitors combined with statins) and control group (n = 35, statins only). Blood lipid levels, inflammatory markers and pulse wave velocity (PWV) data were collected before treatment and at 1 and 6 months after treatment for analysis. Additionally, cell experiments were conducted to investigate the impact of PCSK9i on osteogenesis of vascular smooth muscle cells (VSMCs), utilizing western blot (WB), enzyme-linked immunosorbent assay (ELISA), and calcification index measurements.

Results

The results of the MR analysis suggest that genetic prediction of PCSK9 inhibition has potential to reduce the PWV. Following treatment of statins combined with PCSK9 inhibitors for 1 and 6 months, the PCSK9i group exhibited significantly lower levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), C-reactive protein (CRP), interleukin-6 (IL-6), fibrinogen (FIB) and procalcitonin (PCT) compared to the control group (p < 0.05). Additionally, PWV in the PCSK9i group demonstrated significant reduction after 6 months of treatment and was found to be associated with the circulating CRP level. In cell experiments, PCSK9i pretreatment ameliorated osteogenesis of VSMCs through reducing the deposition of calcium ions, alkaline phosphatase (ALP) activity, and expression of runt-related transcription factor 2 (RUNX2).

Conclusion

PCSK9i have potential to enhance arterial stiffness in ACS patients. Specifically, at the clinical level, this impact may be attributed to alterations in circulating CRP levels. At the cellular level, it is associated with the signaling pathway linked to RUNX2.

Effects of Whey Protein Supplementation on Aortic Stiffness, Cerebral Blood Flow, and Cognitive Function in Community-Dwelling Older Adults: Findings from the ANCHORS A-WHEY Clinical Trial

ANCHORS A-WHEY was a 12-week randomized controlled trial (RCT) designed to examine the effect of whey protein on large artery stiffness, cerebrovascular responses to cognitive activity and cognitive function in older adults. Methods: 99 older adults (mean ± SD; age 67 ± 6 years, BMI 27.2 ± 4.7kg/m², 45% female) were randomly assigned to 50g/daily of whey protein isolate (WPI) or an iso-caloric carbohydrate (CHO) control for 12 weeks (NCT01956994). Aortic stiffness was determined as carotid-femoral pulse wave velocity (cfPWV). Aortic hemodynamic load was assessed as the product of aortic systolic blood pressure and heart rate (Ao SBP × HR). Cerebrovascular response to cognitive activity was assessed as change in middle-cerebral artery (MCA) blood velocity pulsatility index (PI) during a cognitive perturbation (Stroop task). Cognitive function was assessed using a computerized neurocognitive battery. Results: cfPWV increased slightly in CHO and significantly decreased in WPI (p < 0.05). Ao SBP × HR was unaltered in CHO but decreased significantly in WPI (p < 0.05). Although emotion recognition selectively improved with WPI (p < 0.05), WPI had no effect on other domains of cognitive function or MCA PI response to cognitive activity (p > 0.05 for all). Conclusions: Compared to CHO, WPI supplementation results in favorable reductions in aortic stiffness and aortic hemodynamic load with limited effects on cognitive function and cerebrovascular function in community-dwelling older adults.

Ivabradine therapy to unmask heart rate-independent effects of β-blockers on pulse wave reflections

BACKGROUND

Prior studies suggest that β-blockers lead to increased pulse wave reflections, thereby negating the blood pressure lowering effects on cardiovascular mortality. Parts of these effects may be induced by the heart rate reduction under β-blockade. The aim of this study was to unmask heart rate-independent effects of β-blockade on pulse wave reflections by switching therapy from β-blockers to ivabradine, an I f channel inhibitor without impact on systemic hemodynamics.

METHODS

14 male patients (age 61 ± 3 years, LVEF 62 ± 1 %) with arterial hypertension and coronary artery disease (CAD) under chronic β-blocker therapy at moderate dosage and additional renin-angiotensin system-blocking therapy were included. We determined radial augmentation index (rAI) by radial applanation tonometry in patients under β-blockade both at rest and during early recovery after exercise. β-Blockers were then replaced by ivabradine. Six weeks later, patients were re-tested at rest and after exercise under ivabradine therapy.

RESULTS

Mean heart rate (68 ± 3 vs. 63 ± 3 bpm; p = ns) and resting mean arterial pressure (98 ± 2 vs. 98 ± 2 mmHg; p = ns) were not different between β-blocker or ivabradine therapy, respectively. The rAI remained unchanged after switching therapy from β-blocker to ivabradine (86 ± 2 vs. 84 ± 4 %; p = ns). Post exercise, the rAI revealed an identical decrease in both groups (-7.2 ± 2.4 vs. -5.4 ± 2.5 %, p = ns). The increase in heart rate between resting conditions and early recovery post exercise was inversely correlated with the decrease of rAI under β-blockade (r = -0.70; p < 0.01) and showed a trend towards correlation under ivabradine (r = -0.52; p = 0.07).

CONCLUSION

In men at the age of 60 years and CAD, β-blockade does not exert heart rate-independent, pleiotropic effects on peripheral pulse wave reflections, both at rest or after exercise. Our results fit well within recent studies, demonstrating the fundamental influence of heart rate on rAI.

The effects of acute beta-adrenergic blockade on aortic wave reflection in postmenopausal women

BACKGROUND Acute beta-adrenergic blockade increases aortic-wave reflection in young women. However, it is not known whether this effect extends to postmenopausal women. We therefore examined the effect of systemic beta-adrenergic blockade on aortic wave reflection in 14 postmenopausal women with a mean age of 58±2 years. METHODS Aortic pressure waveforms were synthesized noninvasively from high-fidelity radial pressure waveforms obtained through applanation tonometry before and during systemic beta-blockade with propranolol given in a bolus dose of 0.25mg/kg, followed by a continuous infusion at 0.004mg/kg/min. To further examine the effects of acute beta-blockade on aortic-wave reflection in postmenopausal women, we compared the changes in hemodynamics and indices of aortic-wave reflection with published data from a previous study with a protocol identical to that in the present study but which involved young women. RESULTS Acute beta-blockade increased the aortic augmentation index (AIx) in postmenopausal women (32±2% vs. 35±2%, P < 0.01). However, AIx adjusted for a heart rate of 75 bpm (AIx75) was unchanged (25±2% vs. 24±2%, P > 0.05). The changes in AIx, AIx75, and the amplitude of reflected waves (augmented aortic pressure) during beta-blockade were all substantially smaller in postmenopausal women than in their younger counterparts (P < 0.05). Conclusions As compared with those in our previously published study involving young women, indices of aortic-wave reflection were significantly less affected by acute systemic beta-adrenergic blockade in the postmenopausal women in the present study. Taken together, our data suggest that the negative effects (i.e. increased aortic wave reflection) of nonselective beta-adrenergic blockade are less pronounced in postmenopausal than in young women.

Acute β-adrenergic blockade increases aortic wave reflection in young men and women: differing mechanisms between sexes

Acute β-adrenergic blockade increases aortic wave reflection; however, the mechanisms remain unclear. Evidence suggests that β-adrenergic receptor sensitivity in the peripheral vasculature differs between sexes. Therefore, the goal of this study was to examine whether β-adrenergic blockade alters aortic wave reflection to a similar extent in young men and women. In 31 subjects (16 men and 15 women; 26±1 years) noninvasive aortic pressure waveforms were synthesized from high-fidelity radial pressure waveforms via applanation tonometry before and during systemic β-blockade (0.25 mg/kg bolus, followed by 0.004 mg/kg per minute of continuous infusion of propranolol). β-Blockade increased aortic augmentation index and wave reflection amplitude (aortic augmented pressure) in both sexes (P<0.01). Although the increase in augmentation index was not significantly different between sexes (7.5±1.1% versus 4.6±1.5%; P=0.07), the increase in aortic augmented pressure was greater in women compared with men (2.8±0.5 versus 1.4±0.5 mm Hg; P<0.05). Aortic augmentation index adjusted for a heart rate of 75 bp increased in women (4.1±1.1%; P<0.05) after β-blockade, whereas it was unchanged in men (0.6±1.3%; P=0.33). Moreover, the change in aortic augmentation index was inversely associated with the change in heart rate only in men (r=-0.54; P<0.05). Our data suggest that aortic wave reflection is increased to a greater extent in women after systemic β-blockade, and enhanced aortic wave reflection appears to be mediated by a reduced heart rate in men, whereas the mechanism is unclear in women.

Management of Hypertension among Patients with Coronary Heart Disease

Evidence suggests that coronary heart disease (CHD) is the most common outcome of hypertension. Hypertension accelerates the development of atherosclerosis, and sustained elevation of blood pressure (BP) can destabilize vascular lesions and precipitate acute coronary events. Hypertension can cause myocardial ischemia in the absence of CHD. These cardiovascular risks attributed to hypertension can be reduced by optimal BP control. Although several antihypertensive agents exist, the choice of agent and the appropriate target BP for patients with CHD remain controversial. In this succinct paper, we examine the evidence and the mechanisms for the linkage between hypertension and CHD and we discuss the treatment options and the goals of therapy that are consistent with the report of the seventh Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) and American Heart Association scientific statement. We anticipate changes in the recommendations of the forthcoming JNC 8.