Impact of breakthrough COVID-19 cases during the omicron wave on vascular health and cardiac autonomic function in young adults

Risk factors for severe COVID-19 disease increase SARS-CoV-2 infectivity of endothelial cells and pericytes

Coronavirus disease 2019 (COVID-19) was initially considered a primarily respiratory disease but is now known to affect other organs including the heart and brain. A major route by which COVID-19 impacts different organs is via the vascular system. We studied the impact of apolipoprotein E (APOE) genotype and inflammation on vascular infectivity by pseudo-typed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viruses in mouse and human cultured endothelial cells and pericytes. Possessing the APOE4 allele or having existing systemic inflammation is known to enhance the severity of COVID-19. Using targeted replacement human APOE3 and APOE4 mice and inflammation induced by bacterial lipopolysaccharide (LPS), we investigated infection by SARS-CoV-2. Here, we show that infectivity was higher in murine cerebrovascular pericytes compared to endothelial cells and higher in cultures expressing APOE4. Furthermore, increasing the inflammatory state of the cells by prior incubation with LPS increased infectivity into human and mouse pericytes and human endothelial cells. Our findings provide insights into the mechanisms underlying severe COVID-19 infection, highlighting how risk factors such as APOE4 genotype and prior inflammation may exacerbate disease severity by augmenting the virus's ability to infect vascular cells.

Different clinical characteristics and outcomes of adult hospitalized SARS-CoV-2 pneumonia patients complicated by cardiovascular events during the first, delta and omicron waves of COVID-19

Background

The effects of SARS-CoV-2 have varied between significant waves of hospitalization.

Research question

Are cardiovascular complications different among the first, delta and omicron waves of hospitalized COVID-19 pneumonia patients?

Study design and methods

This was a multi-centre retrospective study of patients hospitalized with SARS-CoV-2 pneumonia: 632 were hospitalized during the first wave (March-July 2020), 1013 during the delta wave (September 2020-March 2021), and 323 during the omicron wave (January 2022-July 2022). Patients were stratified by wave and occurrence of cardiovascular events.

Results

Among all hospitalized patients with cardiovascular events, patients in the omicron wave were younger (62.4 ± 14 years) than patients in the first wave (67.4 ± 7.8 years) and the delta wave (66.9 ± 12.6 years) and had a higher proportion of non-Hispanic White people than in the first wave (78.6% vs. 61.7%). For COVID-19 patients who suffered from cardiovascular events, the omicron wave patients had significantly higher neutrophil/lymphocyte ratio, white blood cell and platelet counts when compared to the first wave. Omicron wave patients had significantly lower albumin and B-type natriuretic peptide levels (only 5.8% of the first wave and 14.6% of the delta wave) when compared to either the first wave or delta wave patients. In COVID-19 patients who suffered cardiovascular events during hospitalization, mortality rate in the omicron wave (26.8%) was significantly lower than the first wave (48.3%), time to mortality for non-survivors of COVID-19 patients who suffered cardiovascular events was significantly longer in the omicron wave (median 16 days) than in the first wave (median 10 days).

Conclusions

Younger and white patients were affected with cardiovascular complications more often by the omicron variant. Despite higher neutrophil/lymphocyte ratio and WBC counts, the omicron patients with cardiovascular events showed lower heart injuries, lower mortality and longer time to mortality for non-survivors when compared to the first and delta waves.

Cardiac autonomic function is preserved in young adults with major depressive disorder

The prevalence of major depressive disorder (MDD) is highest in young adults and contributes to an increased risk of developing future cardiovascular disease (CVD). However, the underlying mechanisms remain unclear. The studies examining cardiac autonomic function that have included young unmedicated adults with MDD report equivocal findings, and few have considered the potential influence of disease severity or duration. We hypothesized that heart rate variability (HRV) and cardiac baroreflex sensitivity (BRS) would be reduced in young unmedicated adults with MDD (18-30 yr old) compared with healthy nondepressed young adults (HA). We further hypothesized that greater symptom severity would be related to poorer cardiac autonomic function in young adults with MDD. Heart rate and beat-to-beat blood pressure were continuously recorded during 10 min of supine rest to assess HRV and cardiac BRS in 28 HA (17 female, 22 ± 3 yr old) and 37 adults with MDD experiencing current symptoms of mild-to-moderate severity (unmedicated; 28 female, 20 ± 3 yr old). Neither HRV [root mean square of successive differences between normal heartbeats (RMSSD): 63 ± 34 HA vs. 79 ± 36 ms MDD; P = 0.14] nor cardiac BRS (overall gain, 21 ± 10 HA vs. 23 ± 7 ms/mmHg MDD; P = 0.59) were different between groups. In young adults with MDD, there was no association between current depressive symptom severity and either HRV (RMSSD, R2 = 0.004, P = 0.73) or cardiac BRS (overall gain, R2 = 0.02, P = 0.85). Taken together, these data suggest that cardiac autonomic dysfunction may not contribute to elevated cardiovascular risk factor profiles in young unmedicated adults with MDD of mild-to-moderate severity.NEW & NOTEWORTHY This study investigated cardiac autonomic function in young unmedicated adults with major depressive disorder (MDD). The results demonstrated that both heart rate variability and cardiac baroreflex sensitivity were preserved in young unmedicated adults with MDD compared with healthy nondepressed young adults. Furthermore, in young adults with MDD, current depressive symptom severity was not associated with any indices of cardiac autonomic function.

Damage to endothelial barriers and its contribution to long COVID

The world continues to contend with COVID-19, fueled by the emergence of viral variants. At the same time, a subset of convalescent individuals continues to experience persistent and prolonged sequelae, known as long COVID. Clinical, autopsy, animal and in vitro studies all reveal endothelial injury in acute COVID-19 and convalescent patients. Endothelial dysfunction is now recognized as a central factor in COVID-19 progression and long COVID development. Different organs contain different types of endothelia, each with specific features, forming different endothelial barriers and executing different physiological functions. Endothelial injury results in contraction of cell margins (increased permeability), shedding of glycocalyx, extension of phosphatidylserine-rich filopods, and barrier damage. During acute SARS-CoV-2 infection, damaged endothelial cells promote diffuse microthrombi and destroy the endothelial (including blood-air, blood-brain, glomerular filtration and intestinal-blood) barriers, leading to multiple organ dysfunction. During the convalescence period, a subset of patients is unable to fully recover due to persistent endothelial dysfunction, contributing to long COVID. There is still an important knowledge gap between endothelial barrier damage in different organs and COVID-19 sequelae. In this article, we mainly focus on these endothelial barriers and their contribution to long COVID.

Applicability of heart rate variability for cardiac autonomic assessment in long-term COVID patients: A systematic review

PURPOSE

To carry out a systematic review to determine the main methods used to study the heart rate variability (HRV) in individuals after the acute phase of COVID-19.

METHODS

The study followed the Preferred Items for Reporting for Systematic Reviews and Meta-Analyses (PRISMA) statement. PubMed, Web of Science, Scopus and CINAHAL electronic databases were searched from the inception to November 2022. The studies were included if they used HRV assessment based on linear and non-linear methods in long-term COVID-19 patients. Review studies, theses and dissertations, conference abstracts, longitudinal studies, studies conducted on animals and studies that included individuals in the acute phase of the COVID-19 were excluded. The methodological quality of the studies was analyzed using the Joanna Briggs Institute's critical evaluation checklist for cross-sectional analytical studies.

RESULTS

HRV was mainly assessed using 24-h Holter monitoring in 41.6% (5/12) of the studies, and 12‑lead ECG was used in 33.3% (4/12). Regarding the type of assessment, 66.6% (8/12) of the studies only used linear analysis, where 25% (3/12) used analysis in the time domain, and 41.6% (5/12) used both types. Non-linear methods were combined with the previously cited linear method in 25% (3/12) of the studies. Moreover, 50% (6/12) of the studies demonstrated post-COVID-19 autonomic dysfunction, with an increase in the predominance of cardiac sympathetic modulation. The average score of the evaluation checklist was 6.6, characterized as having reasonable methodological quality.

CONCLUSION

24-h Holter and 12‑lead ECG are considered effective tools to assess HRV in post-COVID-19 patients. Furthermore, the findings reveal diverse effects of COVID-19 on the autonomic nervous system's sympathovagal balance, which might be influenced by secondary factors such as disease severity, patients' overall health, evaluation timing, post-infection complications, ventilatory functions, and age.

SARS-CoV-2 and the spike protein in endotheliopathy

SARS-CoV-2, the causative agent of COVID-19, primarily affects the epithelial compartment in the upper and lower airways. There is evidence that the microvasculature in both the pulmonary and extrapulmonary systems is a major target of SARS-CoV-2. Consistent with this, vascular dysfunction and thrombosis are the most severe complications in COVID-19. The proinflammatory milieu triggered by the hyperactivation of the immune system by SARS-CoV-2 has been suggested to be the main trigger for endothelial dysfunction during COVID-19. More recently, a rapidly growing number of reports have indicated that SARS-CoV-2 can interact directly with endothelial cells through the spike protein, leading to multiple instances of endothelial dysfunction. Here, we describe all the available findings showing the direct effect of the SARS-CoV-2 spike protein on endothelial cells and offer mechanistic insights into the molecular basis of vascular dysfunction in severe COVID-19.

Baroreflex sensitivity is impaired in survivors of mild COVID-19 at 3-6 months of clinical recovery; association with carotid artery stiffness

The association between the stiffening of barosensitive regions of central arteries and the derangements in baroreflex functions remains unexplored in COVID-19 survivors. Fifty-seven survivors of mild COVID-19 (defined as presence of upper respiratory tract symptoms and/or fever without shortness of breath or hypoxia; SpO2 > 93%), with an age range of 22-66 years (27 females) participated at 3-6 months of recovering from the acute phase of RT-PCR positive COVID-19. Healthy volunteers whose baroreflex sensitivity (BRS) and arterial stiffness data were acquired prior to the onset of the pandemic constituted the control group. BRS was found to be significantly lower in the COVID survivor group for the systolic blood pressure-based sequences (BRSSBP ) [9.78 (7.16-17.74) ms/mmHg vs 16.5 (11.25-23.78) ms/mmHg; p = 0.0253]. The COVID survivor group showed significantly higher carotid β stiffness index [7.16 (5.75-8.18) vs 5.64 (4.34-6.96); (p = 0.0004)], and pulse wave velocity β (PWVβ ) [5.67 (4.96-6.32) m/s vs 5.12 (4.37-5.41) m/s; p = 0.0002]. BRS quantified by both the sequence and spectral methods showed an inverse correlation with PWVβ in the male survivors. Impairment of BRS in the male survivors of mild COVID-19 at 3-6 months of clinical recovery shows association with carotid artery stiffness.

The Impact of COVID-19 on Carotid-Femoral Pulse Wave Velocity: A Systematic Review and Meta-Analysis

COVID-19 is a complex multisystemic disease that can result in long-term complications and, in severe cases, death. This study investigated the effect of COVID-19 on carotid-femoral pulse wave velocity (cfPWV) as a measurement to evaluate its impact on arterial stiffness and might help predict COVID-19-related cardiovascular (CV) complications. PubMed, Web of Science, Embase, and the Cochrane Library were searched for relevant studies, and meta-analysis was performed. The study protocol was registered in PROSPERO (nr. CRD42023434326). The Newcastle-Ottawa Quality Scale was used to evaluate the quality of the included studies. Nine studies reported cfPWV among COVID-19 patients and control groups. The pooled analysis showed that cfPWV in COVID-19 patients was 9.5 ± 3.7, compared to 8.2 ± 2.2 in control groups (MD = 1.32; 95% CI: 0.38-2.26; p = 0.006). A strong association between COVID-19 infection and increased cfPWV suggests a potential link between the virus and increased arterial stiffness. A marked increase in arterial stiffness, a known indicator of CV risk, clearly illustrates the cardiovascular implications of COVID-19 infection. However, further research is required to provide a clearer understanding of the connection between COVID-19 infection, arterial compliance, and subsequent CV events.

Impact of Environmental Factors on Hypertension and Associated Cardiovascular Disease

Hypertension is the primary cause of cardiovascular diseases and is responsible for nearly 9 million deaths worldwide annually. Increasing evidence indicates that in addition to pathophysiologic processes, numerous environmental factors, such as geographic location, lifestyle choices, socioeconomic status, and cultural practices, influence the risk, progression, and severity of hypertension, even in the absence of genetic risk factors. In this review, we discuss the impact of some environmental determinants on hypertension. We focus on clinical data from large population studies and discuss some potential molecular and cellular mechanisms. We highlight how these environmental determinants are interconnected, as small changes in one factor might affect others, and further affect cardiovascular health. In addition, we discuss the crucial impact of socioeconomic factors and how these determinants influence diverse communities with economic disparities. Finally, we address opportunities and challenges for new research to address gaps in knowledge on understanding molecular mechanisms whereby environmental factors influence development of hypertension and associated cardiovascular disease.

COVID-19 and Cerebrovascular Disease

COVID-19 has been associated with numerous neurological complications, with acute cerebrovascular disease being one of the most devastating complications. Ischemic stroke is the most common cerebrovascular complication of COVID-19, affecting between 1 and 6% of all patients. Underlying mechanisms for COVID-related ischemic strokes are thought to be due to vasculopathy, endotheliopathy, direct invasion of the arterial wall, and platelet activation. Other COVID-19-associated cerebrovascular complications include hemorrhagic stroke, cerebral microbleeds, posterior reversible encephalopathy syndrome, reversible cerebral vasoconstriction syndrome, cerebral venous sinus thrombosis, and subarachnoid hemorrhage. This article discusses the incidence of these cerebrovascular complications, risk factors, management strategies, prognosis and future research directions, as well as considerations in pregnancy-related cerebrovascular events in the setting of COVID-19.

Current topic of vascular function in hypertension

Vascular function assessment is useful for the evaluation of atherosclerosis severity, which may provide additional information for cardiovascular risk stratification. In addition, vascular function assessment is helpful for a better understanding of pathophysiological associations between vascular dysfunction and cardiometabolic disorders. In 2020 and 2021, although coronavirus disease 2019 (COVID-19) was still a worldwide challenge for health care systems, many excellent articles regarding vascular function were published in Hypertension Research and other major cardiovascular and hypertension journals. In this review, we summarize new findings on vascular function and discuss the association between vascular function and COVID-19, the importance of lifestyle modifications for the maintenance of vascular function, and the usefulness of vascular function tests for cardiovascular risk assessment. We hope this review will be helpful for the management of cardiovascular risk factors, including hypertension and cardiovascular diseases, in clinical practice.

The Impact of SARS-CoV-2 Infection on Heart Rate Variability: A Systematic Review of Observational Studies with Control Groups

Autonomic nervous system (ANS) dysfunction can arise after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and heart rate variability (HRV) tests can assess its integrity. This review investigated the relationship between the impact of SARS-CoV-2 infection on HRV parameters. Comprehensive searches were conducted in four electronic databases. Observational studies with a control group reporting the direct impact of SARS-CoV-2 infection on the HRV parameters in July 2022 were included. A total of 17 observational studies were included in this review. The square root of the mean squared differences of successive NN intervals (RMSSD) was the most frequently investigated. Some studies found that decreases in RMSSD and high frequency (HF) power were associated with SARS-CoV-2 infection or the poor prognosis of COVID-19. Also, decreases in RMSSD and increases in the normalized unit of HF power were related to death in critically ill COVID-19 patients. The findings showed that SARS-CoV-2 infection, and the severity and prognosis of COVID-19, are likely to be reflected in some HRV-related parameters. However, the considerable heterogeneity of the included studies was highlighted. The methodological quality of the included observational studies was not optimal. The findings suggest rigorous and accurate measurements of HRV parameters are highly needed on this topic.

Impact of COVID-19 Vaccination on Heart Rate Variability: A Systematic Review

Establishing and disseminating evidence-based safety information could potentially facilitate beneficial choices in coronavirus disease (COVID-19) vaccinations. This systematic review investigated the potential impact of COVID-19 vaccinations on human heart rate variability (HRV) parameters through comprehensive searches of four electronic medical databases. Five observational studies reporting HRV parameters of individuals vaccinated against COVID-19 and published up to 29 July 2022 were included in this review. Among them, four studies reported the square root of the mean squared differences of successive NN intervals (RMSSD) as their outcome, and the remaining study reported an HRV-based stress indicator. These studies reported short-term changes and rapid recovery in HRV parameters within up to 3 days after COVID-19 vaccination. Some studies showed that the impact of COVID-19 vaccinations on RMSSD was greater in women than men, and in the younger group than in the older group. The methodological quality of the included studies was not optimal; the review revealed short-term changes in HRV parameters, particularly RMSSD, following COVID-19 vaccination. However, as the included studies did not report important parameters besides RMSSD, the limitation exists that the postvaccination long-term HRV stability was not reported.

Impact of COVID-19 on cardiac autonomic function in healthy young adults: potential role of symptomatology and time since diagnosis

Emerging evidence suggests that COVID-19 may affect cardiac autonomic function; however, the limited findings in young adults with COVID-19 have been equivocal. Notably, symptomology and time since diagnosis appear to influence vascular health following COVID-19, but this has not been explored in the context of cardiac autonomic regulation. Therefore, we hypothesized that young adults who had persistent symptoms following COVID-19 would have lower heart rate variability (HRV) and cardiac baroreflex sensitivity (BRS) compared with those who had COVID-19 but were asymptomatic at testing and controls who never had COVID-19. Furthermore, we hypothesized that there would be relationships between cardiac autonomic function measures and time since diagnosis. We studied 27 adults who had COVID-19 and were either asymptomatic (ASYM; n = 15, 6 females); 21 ± 4 yr; 8.4 ± 4.0 wk from diagnosis) or symptomatic (SYM; n = 12, 9 females); 24 ± 3 yr; 12.3 ± 6.2 wk from diagnosis) at testing, and 20 adults who reported never having COVID-19 (24 ± 4 yr, 11 females). Heart rate and beat-to-beat blood pressure were continuously recorded during 5 min of rest to assess HRV and cardiac BRS. HRV [root mean square of successive differences between normal heartbeats (RMSSD); control, 73 ± 50 ms; ASYM, 71 ± 47 ms; and SYM, 84 ± 45 ms; P = 0.774] and cardiac BRS (overall gain; control, 22.3 ± 10.1 ms/mmHg; ASYM, 22.7 ± 12.2 ms/mmHg; and SYM, 24.3 ± 10.8 ms/mmHg; P = 0.871) were not different between groups. However, we found correlations with time since diagnosis for HRV (e.g., RMSSD, r = 0.460, P = 0.016) and cardiac BRS (overall gain, r = 0.470, P = 0.014). These data suggest a transient impact of COVID-19 on cardiac autonomic function that appears mild and unrelated to persistent symptoms in young adults.NEW & NOTEWORTHY The potential role of persistent COVID-19 symptoms on cardiac autonomic function in young adults was investigated. We observed no differences in heart rate variability or cardiac baroreflex sensitivity between controls who never had COVID-19 and those who had COVID-19, regardless of symptomology. However, there were significant relationships between measures of cardiac autonomic function and time since diagnosis, suggesting that COVID-19-related changes in cardiac autonomic function are transient in young, otherwise healthy adults.