Comparison between ticagrelor and clopidogrel in high bleeding risk patients with acute coronary syndrome

Background

Potent antiplatelet agents such as ticagrelor are associated with a lower risk of ischemic events than clopidogrel in patients with acute coronary syndrome (ACS). However, it is uncertain whether the benefits of more intensive anti-ischemic therapy outweigh the risks of major bleeding in individuals who have a high bleeding risk (HBR). This study aimed to assess treatment outcomes following dual antiplatelet therapy (DAPT) using either ticagrelor or clopidogrel in ACS patients with HBR.

Methods

All HBR patients enrolled in the SWEDEHEART registry who were discharged with DAPT using ticagrelor or clopidogrel following ACS between 2010 and 2017 were included in this study. Bleeding risk was assessed using the 4-item PRECISE-DAPT score, which consists of age, prior bleeding, haemoglobin concentration and creatinine clearance. HBR was defined as a PRECISE-DAPT score ≥25. Inverse-probability of treatment weighting was used to adjust for baseline differences between the treatment groups. The main analysis consisted of a doubly robust estimation of causal effect using Cox proportional hazards models. Data on major bleeding, recurrent myocardial infarction (MI), ischemic stroke and all-cause mortality was obtained from national registries, with 365 days of follow-up. Additional outcomes include major adverse cardiovascular events (MACE), a composite of MI, ischemic stroke and all-cause mortality, and net adverse clinical events (NACE), a composite of MACE and major bleeding.

Results

Of all ACS patients, 36% (n=25,042) had a PRECISE-DAPT score ≥25. Approximately half of the study participants were treated with ticagrelor (n=11,848). Ticagrelor reduced the risk of MI (hazard ratio [HR], 0.82 [95% CI 0.74–0.91]), ischemic stroke (HR, 0.73 [95% CI 0.60–0.88]) and MACE (HR, 0.90 [95% CI 0.84–0.97]), while also increasing the risk of major bleeding compared to clopidogrel (HR, 1.30 [95% CI 1.16–1.47]). We found no significant differences in all-cause mortality (HR 1.02 [95% CI 0.92–1.12]) and NACE (HR 0.98 [95% CI 0.92–1.05]).

Conclusions

Ticagrelor was associated with a lower risk of recurrent ischemic events, but a higher risk of major bleeding compared to clopidogrel. There were no significant differences in all-cause mortality and NACE between the treatment groups. These results suggest that more potent antiplatelet agents might not be superior to clopidogrel in ACS patients with HBR.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Stockholm county council

The association of mode of location activity and mobility with acute coronary syndrome: a nationwide ecological study

BACKGROUND

We aimed to study the effect of social containment mandates on ACS presentation during COVID-19 pandemic using location activity and mobility data from mobile phone map services.

METHODS

We conducted a cross-sectional study using data from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) including all ACS presentations during the pandemic until 7 May 2020. Using a count regression model, we adjusted for day of the week, daily weather and incidence of COVID-19.

RESULTS

A 10% increase in activity around areas of residence was associated with 38% lower rates of ACS hospitalizations, whereas increased activity relating to retail and recreation, grocery stores and pharmacies, workplaces and mode of mobility was associated with 10-20% higher rates of ACS hospitalizations.

CONCLUSION

Government policy regarding social containment mandates has important public health implications for medical emergencies such as ACS and may explain the decline in ACS presentations observed during COVID-19 pandemic.

P6392Under the weather: acute myocardial infarction and subsequent case fatality with influenza burden - a nationwide observational study

Background

Influenza may precipitate cardiovascular disease but influenza typically peaks in winter coinciding with other triggers of myocardial infarction (MI) such as low air temperature, high wind velocity, low air pressure and short sunshine duration. We aimed to study week-to-week variation in influenza cases and acute MI after meteorological confounder adjustment in a nationwide setting.

Methods

Weekly laboratory-confirmed influenza case reports were obtained from the Public Health Agency of Sweden from 2009 to 2016 and merged with the nationwide SWEDEHEART MI registry. Weekly counts of MI were studied with regard to influenza cases stratified into tertiles, 0–16, 17–164 and >164 influenza cases/week. Incidence rate ratios were calculated for each category and compared to a reference period of the year with no influenza. A negative binomial regression model was applied to adjust for weather parameters.

Results

A total of 133 562 MIs were reported to the registry during the study period of which 44 055 were ST-elevation MIs. Weeks with influenza cases were associated with higher risk of MI. For 0–16 influenza cases/week the unadjusted incidence rate ratio (IRR) for MI was 1.04 (95% confidence interval [CI] 1.01–1.07, p=0.007); for 17–163 cases/week the IRR=1.07 (95% CI 1.04–1.10, p≤0.001) and for ≥164 cases/week the IRR=1.08 (95% CI 1.05–1.11, p≤0.001). Results were consistent across a large range of subgroups and after adjusting for confounders. In addition, all-cause mortality was higher in weeks with highest reported rates of influenza cases.

Conclusion

In this nationwide observational study, we found an association between occurrence of MI and number of influenza cases beyond what could be explained by meteorological factors.

A Designer Synbiotic Attenuates Chronic-Binge Ethanol-Induced Gut-Liver Injury in Mice

Gut dysbiosis and altered short-chain fatty acids are associated with ethanol-induced liver injury. SCFA are fermentation byproducts of the gut microbiota known to have many beneficial biological effects. We tested if a designer synbiotic could protect against ethanol-induced gut-liver injury. C57BL/6 female mice were exposed to chronic-binge ethanol feeding consisting of ethanol (5% vol/vol) for 10 days, followed by a single gavage (5 g/kg body weight) 6 h before euthanasia. A group of mice also received oral supplementation daily with a designer synbiotic, and another group received fecal slurry (FS); control animals received saline. Control mice were isocalorically substituted maltose dextran for ethanol over the entire exposure period. Ethanol exposure reduced expression of tight junction proteins in the proximal colon and induced hepatocyte injury and steatosis. Synbiotic supplementation not only mitigated losses in tight junction protein expression, but also prevented ethanol-induced steatosis and hepatocyte injury. Ethanol exposure also increased hepatic inflammation and oxidative stress, which was also attenuated by synbiotic supplementation. Mice receiving FS were not protected from ethanol-induced liver injury or steatosis. Results were associated with luminal SCFA levels and SCFA transporter expression in the proximal colon and liver. These results indicate supplementation with a designer synbiotic is effective in attenuating chronic-binge ethanol-induced gut-liver injury and steatosis in mice, and highlight the beneficial effects of the gut microbial fermentation byproducts.

Development and evaluation of nanoemulsion and microsuspension formulations of curcuminoids for lung delivery with a novel approach to understanding the aerosol performance of nanoparticles

Extensive research has demonstrated the potential effectiveness of curcumin against various diseases, including asthma and cancers. However, few studies have used liquid-based vehicles in the preparation of curcumin formulations. Therefore, the current study proposed the use of nanoemulsion and microsuspension formulations to prepare nebulised curcuminoid for lung delivery. Furthermore, this work expressed a new approach to understanding the aerosol performance of nanoparticles compared to microsuspension formulations. The genotoxicity of the formulations was also assessed. Curcuminoid nanoemulsion formulations were prepared in three concentrations (100, 250 and 500 µg/ml) using limonene and oleic acid as oil phases, while microsuspension solutions were prepared by suspending curcuminoid particles in isotonic solution (saline solution) of 0.02% Tween 80. The average fine particle fraction (FPF) and mass median aerodynamic diameter (MMAD) of the nebulised microsuspension formulations ranged from 26% and 7.1 µm to 40% and 5.7 µm, for 1000 µg/ml and 100 µg/ml respectively. In a comparison of the low and high drug concentrations of the nebulised nanoemulsion, the average FPF and MMAD of the nebulised nanoemulsion formulations prepared with limonene oil ranged from 50% and 4.6 µm to 45% and 5.6 µm, respectively; whereas the FPF and MMAD of the nebulised nanoemulsion prepared with oleic acid oil ranged from 46% and 4.9 µm to 44% and 5.6 µm, respectively. The aerosol performance of the microsuspension formulations were concentration dependent, while the nanoemulsion formulations did not appear to be dependent on the curcuminoids concentration. The performance and genotoxicity results of the formulations suggest the suitability of these preparations for further inhalation studies in animals.

The distribution of heavy-chain isoforms of myosin in airways smooth muscle from adult and neonate humans

Changes in the expression of heavy chains of myosin during development determine the functional characteristics of striated muscles. The distribution of heavy-chain isoforms of smooth-muscle myosin was determined in the airways of adult and infant humans to see whether it might underlie the hyperreactivity of human airways. The protein bands corresponding to myosin were separated using SDS/polyacrylamide-gel electrophoresis (4% gels) and identified by immunoblotting using both monoclonal and polyclonal antibodies against smooth-muscle myosin and non-muscle myosin. The relative proportion of each heavy chain stained by Coomassie Blue was measured by densitometric scanning. Three major bands corresponding to myosin heavy-chain isoforms were found; the two slower migrating bands (MHC1 and MHC2) were smooth-muscle myosin, and the third band was non-muscle myosin. The MHC1/MHC2 ratio was 0.69:1 in adult bronchus, and in infant bronchus and trachea. This contrasted with the airway smooth muscle in pigs, which was run concurrently, where the smooth-muscle heavy-chain ratio changed with development [Mohammad & Sparrow (1988) FEBS Lett. 228, 109-112]. The non-muscle myosin heavy chain comprised 63% of the smooth-muscle myosin. In both adult and infant lungs an additional putative myosin heavy chain which migrated slightly more rapidly than non-muscle myosin heavy chain was identified using the monoclonal smooth-muscle myosin antibody BF 48. This was unique to the human species.

Ivermectin, levamisole and thymic extract for chemotherapy and immunostimulation of visceral leishmaniasis in hamsters and mice

The anti-leishmanial activity of ivermectin, pentostam or combination of pentostam with either levamisole or thymic extract was tested against Leishmania donovani infection in hamsters and mice. In vitro peritoneal macrophage-parasite interaction, the effect of splenic cells on the interaction of macrophages and parasites, spleen weight, parasite burden in spleen tissue as well as the antibody titers using micro-ELISA were used as parameters for evaluating the efficacy of these chemotherapeutic regimens. Treatment with ivermectin and immunoenhancement with pentostam combined with levamisole gave best results in both animal models. Furthermore, regimens used in this work were all active in reducing phagocytosis of promastigotes by macrophages in vitro.

Myosin composition and functional properties of smooth muscle from the uterus of pregnant and non-pregnant rats

The myosin heavy chain stoichiometry and the force-velocity relation have been determined in the myometrium of the non-pregnant and pregnant rat. The relative proportions of the slower migrating heavy chain (MHC1) greatly exceeded that of the faster migrating heavy chain (MHC2) as shown by electrophoresis on SDS 4%-polyacrylamide gels. The ratios of MHC1/MHC2 were 2.2/1 in the non-pregnant rats, 2.6/1 in the pregnant rat, and contrasted with 0.8/1 in the rat portal vein. This stoichiometry was unchanged by extracting the myosin from the smooth muscle as native myosin in a salt extract, as dissociated myosin using sodium dodecyl sulphate (SDS) or by isolating the native myosin first by a non-dissociating (pyrophosphate) electrophoresis step and subsequently analysing the protein bands on the SDS 4%-polyacrylamide gel. Although the unequal proportions of the heavy chains suggested the possibility that the native myosin molecule may be arranged as homodimeric heavy chains, no evidence for or against the existence of native myosin isoforms could be obtained by electrophoresing native myosin extracts on pyrophosphate-polyacrylamide gels. The force-velocity relations of the intact electrically stimulated myometrium from the non-pregnant and pregnant rats gave isometric force of 45 and 135 mN/mm2 and Vmax of 0.71 and 0.52 lengths/s (37 degrees C) when measured at 95% of optimal length, whereas in chemically skinned uterine strips at 22 degrees C Vmax was 0.09 and 0.13 lengths/s, respectively. The length-force relationship was of similar shape in the non-gravid and gravid skinned tissues. The energetic tension cost (ATP-turnover/active stress) in skinned fibres was also similar. The mechanical and metabolic characteristics of the gravid and non-gravid uterus found in the present study do not suggest an obvious difference in the intrinsic properties of the myosin, although significant functional alterations in the tissue appear during pregnancy. This corresponds to the lack of a difference in the pattern of the heavy chains.

Changes in myosin heavy chain stoichiometry in pig tracheal smooth muscle during development

The stoichiometry of the myosin heavy chains (MHCs) has been measured in the tracheal smooth muscle of the pig after electrophoresis on SDS 4% polyacrylamide gel. The ratio of slower migrating MHC to the faster migrating MHC was 2.1 neonates, 1.5 in young and 0.95 in old pigs (P less than 0.01) showing that MHC composition changes with development. The unequal proportion of MHCs was not compatible with a heterodimeric arrangement of the MHCs in the native molecule as proposed earlier by Rovner et al. [(1986) Am. J. Physiol. 250, C861-870] and it is suggested that native molecules may be composed of homodimer heavy chains.

The heavy-chain stoichiometry of smooth muscle myosin is a characteristic of smooth muscle tissues

The stoichiometry of the two heavy chains of myosin in smooth muscle was determined by electrophoresing extracts of native myosin and of dissociated myosin on sodium dodecyl sulfate (SDS) 4%-polyacrylamide gels. The slower migrating heavy chain was 3.6 times more abundant in toad stomach, 2.3 in rabbit myometrium, 2.0 in rat femoral artery, 1.3 in guinea pig ileum, 0.93 in pig trachea and 0.69 in human bronchus, than the more rapidly migrating chain. Both heavy chains were identified as smooth muscle myosin by immunoblotting using antibodies to smooth muscle and non-muscle myosin. The unequal proportion of heavy chains suggested the possibility of native isoforms of myosin comprised of heavy-chain homodimers. To test this, native myosin extracts wer electrophoresed on non-dissociating (pyrophosphate) gels. When each band was individually analysed on SDS-polyacrylamide gel the slowest was found to be filamin and the other bands were myosin in which the relative proportion of the heavy chains was unchanged from that found in the original tissue extracts. Since this is incompatible with either a heterodimeric or a homodimeric arrangement it suggests that pyrophosphate gel electrophoresis is incapable of separating putative isoforms of native myosin.