Impact of the COVID-19 pandemic on hospitalizations for acute coronary syndromes: a multinational study

BACKGROUND

COVID-19 has challenged the health system organization requiring a fast reorganization of diagnostic/therapeutic pathways for patients affected by time-dependent diseases such as acute coronary syndromes (ACS).

AIM

To describe ACS hospitalizations, management, and complication rate before and after the COVID-19 pandemic was declared.

DESIGN

Ecological retrospective study. Methods: We analyzed aggregated epidemiological data of all patients > 18 years old admitted for ACS in twenty-nine hub cardiac centers from 17 Countries across 4 continents, from December 1st, 2019 to April 15th, 2020. Data from December 2018 to April 2019 were used as historical period.

RESULTS

A significant overall trend for reduction in the weekly number of ACS hospitalizations was observed (20.2%; 95% confidence interval CI [1.6, 35.4] P = 0.04). The incidence rate reached a 54% reduction during the second week of April (incidence rate ratio: 0.46, 95% CI [0.36, 0.58]) and was also significant when compared to the same months in 2019 (March and April, respectively IRR: 0.56, 95%CI [0.48, 0.67]; IRR: 0.43, 95%CI [0.32, 0.58] p < 0.001). A significant increase in door-to-balloon, door-to-needle, and total ischemic time (p <0.04 for all) in STEMI patents were reported during pandemic period. Finally, the proportion of patients with mechanical complications was higher (1.98% vs. 0.98%; P = 0.006) whereas GRACE risk score was not different.

CONCLUSIONS

Our results confirm that COVID-19 pandemic was associated with a significant decrease in ACS hospitalizations rate, an increase in total ischemic time and a higher rate of mechanical complications on a international scale.

Circulating levels of proprotein convertase subtilisin/kexin type 9 (PCSK9) are associated with monocyte subsets in patients with stable coronary artery disease

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): FWF

Background and aims

Proprotein convertase subtilisin/kexin type-9 (PCSK9) is an enzyme promoting the degradation of low-density lipoprotein receptors (LDL-R) in hepatocytes. Inhibition of PCSK9 has emerged as a novel target for lipid-lowering therapy. Monocytes are crucially involved in the pathogenesis of atherosclerosis and can be divided into three subsets. The aim of this study was to examine whether circulating levels of PCSK9 are associated with monocyte subsets.

Methods

We included 69 patients with stable coronary artery disease. PCSK9 levels were measured and monocyte subsets were assessed by flow cytometry and divided into classical monocytes (CD14++CD16-; CM), intermediate monocytes (CD14++CD16+; IM) and non-classical monocytes (CD14 + CD16++; NCM).

Results

Mean age was 64 years and 80% of patients were male. Patients on statin treatment (n = 55) showed higher PCSK9-levels (245.4 (206.0-305.5) ng/mL) as opposed to those without statin treatment (186.1 (162.3-275.4) ng/mL; p = 0.05). In patients on statin treatment, CM correlated with circulating PCSK9 levels (R = 0.29; p = 0.04), while NCM showed an inverse correlation with PCSK9 levels (R=-0.33; p = 0.02). Patients with PCSK9 levels above the median showed a significantly higher proportion of CM as compared to patients with PCSK-9 below the median (83.5 IQR 79.2-86.7 vs. 80.4, IQR 76.5-85.2%; p = 0.05). Conversely, PCSK9 levels &gt;median were associated with a significantly lower proportion of NCM as compared to those with PCSK9 &lt;median (10.2, IQR 7.3-14.6 vs. 14.3, IQR 10.9-18.7%; p = 0.02). In contrast, IM showed no association with PCSK-9 levels.

Conclusions

We hereby provide a novel link between PCSK9 regulation, innate immunity and atherosclerotic disease in statin-treated patients.

P789TLR-4 expression predicts mortality in patients with acute heart failure

Background

Inflammation is regarded as an important trigger for disease progression in heart failure (HF) and activation of the inflammatory system was implicated in the pathophysiology of acute heart failure (AHF).

Toll-like receptors (TLRs) play an important role in acute inflammatory processes in critically ill patients by binding to pathogen associated molecular patterns (PAMP) and danger associated molecular patterns (DAMP). However, it is not known whether the expression patterns of TLRs on neutrophils and monocytes are associated with outcome in patients with severe AHF requiring intensive care unit (ICU) admission.

The aim of this prospective, observational study was to analyze whether TLR-expression on monocytes or neutrophils is associated with 30-day survival in patients with severe AHF.

Methods

We included 84 patients with severe AHF admitted to a cardiac ICU. Blood was taken at admission and mean fluorescence activity (MFI) of TLR-2, TLR-4 and TLR-9 on monocytes and neutrophils was analyzed by flow cytometry.

Results

Median age was 64 (IQR 48–74) years and 76.2% of patients were male. Median NT-proBNP was 4941 (IQR 1298–12273) pg/mL and 30-day mortality was 33.3%. TLR-4 expression on monocytes in survivors (740 IQR 694–854) was significantly lower than in non-survivors (871 IQR 723–979; p<0.05). TLR-2 and TLR-9 expression on monocytes and TLR expression on neutrophils was not associated with survival. TLR-4 expression on monocytes was significantly associated with survival independent of age, sex, creatinine and NT-proBNP levels.

Conclusion

Monocyte TLR-4 expression predicts mortality in patients admitted to a cardiac ICU for severe acute heart failure. This suggests that activation of the innate immune system by TLR-binding of DAMPS may play a significant role in critically ill acute heart failure patients.

Differential in vivo activation of monocyte subsets during low-grade inflammation through experimental endotoxemia in humans

Human monocytes are a heterogeneous cell population, which can be divided into a classical (CD14++CD16−), a non-classical (CD14+CD16+), and an intermediate (CD14++CD16+) subset. We hypothesized that low-grade inflammation may differentially affect monocyte subsets. We used a human lipopolysaccharide (LPS) infusion model to mimic low-grade inflammation to identify, which monocyte subsets are preferentially activated under these conditions. Monocyte subsets were identified by staining for CD14 and CD16, activation status of monocytes was analyzed by staining for CD11b and a novel in situ mRNA hybridization approach to detect IL-6 and IL-8 specific mRNA at the single-cell level by flow cytometry. After LPS challenge, cell numbers of monocyte subsets dropped after 2 h with cell numbers recovering after 6 h. Distribution of monocyte subsets was skewed dramatically towards the intermediate subset after 24 h. Furthermore, intermediate monocytes displayed the largest increase of CD11b expression after 2 h. Finally, IL-6 and IL-8 mRNA levels increased in intermediate and non-classical monocytes after 6 h whereas these mRNA levels in classical monocytes changed only marginally. In conclusion, our data indicates that the main responding subset of monocytes to standardized low-grade inflammation induced by LPS in humans is the CD14++CD16+ intermediate subset followed by the CD14+CD16+ non-classical monocyte subset. Circulating classical monocytes showed comparably less reaction to LPS challenge in vivo.

Cyclic and constant hyperoxia cause inflammation, apoptosis and cell death in human umbilical vein endothelial cells

BACKGROUND

Perioperative high-dose oxygen (O2 ) exposure can cause hyperoxia. While the effect of constant hyperoxia on the vascular endothelium has been investigated to some extent, the impact of cyclic hyperoxia largely remains unknown. We hypothesized that cyclic hyperoxia would induce more injury than constant hyperoxia to human umbilical vein endothelial cells (HUVECs).

METHODS

HUVECs were exposed to cyclic hyperoxia (5-95% O2 ) or constant hyperoxia (95% O2 ), normoxia (21% O2 ), and hypoxia (5% O2 ). Cell growth, viability (Annexin V/propidium iodide and 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide, MTT) lactate dehydrogenase (LDH), release, cytokine (interleukin, IL and macrophage migration inhibitory factor, MIF) release, total antioxidant capacity (TAC), and superoxide dismutase activity (SOD) of cell lysate were assessed at baseline and 8, 24, and 72 h. A signal transduction pathway finder array for gene expression analysis was performed after 8 h.

RESULTS

Constant and cyclic hyperoxia-induced gradually detrimental effects on HUVECs. After 72 h, constant or cyclic hyperoxia exposure induced change in cytotoxic (LDH +12%, P = 0.026; apoptosis +121/61%, P < 0.01; alive cells -15%, P < 0.01; MTT -16/15%, P < 0.01), inflammatory (IL-6 +142/190%, P < 0.01; IL-8 +72/43%, P < 0.01; MIF +147/93%, P < 0.01), or redox-sensitive (SOD +278%, TAC-25% P < 0.01) markers. Gene expression analysis revealed that constant and cyclic hyperoxia exposure differently activates oxidative stress, nuclear factor kappa B, Notch, and peroxisome proliferator-activated receptor pathways.

CONCLUSIONS

Extreme hyperoxia exposure induces inflammation, apoptosis and cell death in HUVECs. Although our findings cannot be transferred to clinical settings, results suggest that hyperoxia exposure may cause vascular injury that could play a role in determining perioperative outcome.

Interleukin-33 induces urokinase in human endothelial cells--possible impact on angiogenesis

BACKGROUND

Urokinase-type plasminogen activator (u-PA) plays a pivotal role in extracellular proteolysis and is thought to be critically involved in the modulation of angiogenesis. Interleukin (IL)-33 is a member of the IL-1 cytokine family, which is thought to act as danger signal that is released from cells after injury. IL-33 is involved in the pathogenesis of various inflammatory diseases and previously was shown to induce angiogenesis and inflammatory activation of endothelial cells.

OBJECTIVE

We investigated the impact of IL-33 on u-PA in endothelial cells as a new possible function for IL-33.

METHODS AND RESULTS

We could demonstrate that IL-33 upregulated u-PA mRNA expression and protein production in human coronary artery and human umbilical vein endothelial cells in a time- and concentration-dependent manner via interaction with its receptor ST2 and activation of the nuclear factor-κB pathway but independent of autocrine IL-1-induced effects. The hydroxymethylglutaryl-coenzyme A reductase inhibitor simvastatin abrogated the IL-33-induced increase in u-PA, thus providing further evidence for pleiotropic effects of statins. IL-33 induced u-PA-dependent capillary-like tube formation and vessel sprouting. In human carotid atherosclerotic plaques (n = 16), u-PA mRNA positively correlated with IL-33 mRNA expression (r = 0.780, P < 0.001). Furthermore, IL-33 and u-PA protein were detected in endothelial cells in these samples using fluorescence immunohistochemistry.

CONCLUSIONS

We hypothesize that IL-33, representing a danger signal that is released after tissue damage, in addition to its role in the inflammatory activation of endothelial cells, is involved in u-PA-driven angiogenesis, a process that has been shown before to be linked to inflammation in various pathologies.

Inflammation and coagulation in atherosclerosis

Cardiovascular diseases remain to be the leading cause of death in Western societies. Despite major findings in vascular biology that lead to a better understanding of the pathomechanisms involved in atherosclerosis, treatment of the disease has only changed slightly within the last years. A big body of evidence suggests that atherosclerosis is a chronic inflammatory disease of the vessel wall. Accumulation and peroxidation of LDL-particles within the vessel wall trigger a strong inflammatory response, causing macrophage and T-cell accumulation within the vessel wall. Additionally, B-cells and specific antibodies against LDL-particles, as well as the complement system are implicated in atherogenesis. Besides data from clinical trials and autopsy studies it was the implementation of mouse models of atherosclerosis and the emerging field of direct gen-modification that lead to a thorough description of the pathophysiological mechanisms involved in the disease and created overwhelming evidence for a participation of the immune system. Recently, the cross-talk between coagulation and inflammation in atherogenesis has gained attention. Serious limitations and disparities in the pathophysiology of atherosclerosis in mice and men complicated the translation of experimental data into clinical practice. Despite these limitations, new anti-inflammatory medical therapies in cardiovascular disease are currently being tested in clinical trials.

Can a flowchart improve the quality of bystander cardiopulmonary resuscitation?

BACKGROUND

Since the introduction of basic life support in the 1950s, on-going efforts have been made to improve the quality of bystander cardiopulmonary resuscitation (CPR). Even though bystander-CPR can increase the chance of survival almost fourfold, the rates of bystander initiated CPR have remained low and rarely exceed 20%. Lack of confidence and fear of committing mistakes are reasons why helpers refrain from initiating CPR. The authors tested the hypothesis that quality and confidence of bystander-CPR can be increased by supplying lay helpers with a basic life support flowchart when commencing CPR, in a simulated resuscitation model.

MATERIALS AND METHODS

After giving written informed consent, 83 medically untrained laypersons were randomised to perform basic life support for 300s with or without a supportive flowchart. The primary outcome parameter was hands-off time (HOT). Furthermore, the participants' confidence in their actions on a 10-point Likert-like scale and time-to-chest compressions were assessed.

RESULTS

Overall HOT was 147±30 s (flowchart) vs. 169±55 s (non-flowchart), p=0.024. Time to chest compressions was significantly longer in the flowchart group (60±24 s vs. 23±18 s, p<0.0001). Participants in the flowchart group were significantly more confident when performing BLS than the non-flowchart counterparts (7±2 vs. 5±2, p=0.0009).

CONCLUSIONS

A chart provided at the beginning of resuscitation attempts improves quality of CPR significantly by decreasing HOT and increasing the participants' confidence when performing CPR. As reducing HOT is associated with improved outcome and positively impacting the helpers' confidence is one of the main obstacles to initiate CPR for lay helpers, charts could be utilised as simple measure to improve outcome in cardiopulmonary arrest.