Adoção da estratégia invasiva precoce no enfarte agudo do miocárdio sem supra desnivelamento de ST: análise dos resultados do Registo Nacional de Síndromas Coronárias Agudas

Effect of oxygen supply on mortality in acute ST-elevation myocardial infarction: systematic review and meta-analysis

Previous studies stated that high oxygen supply in patients with myocardial infarction (MI) was not associated with improved outcomes. However, the particularities of ST-elevation myocardial infarction (STEMI) and the results of a recent trial raised the question if this subgroup of patients benefits from high oxygen supply. This study aims to evaluate the clinical effect of high oxygen supply in patients with STEMI using a systematic review of the available literature. All randomized controlled trials (RCTs) evaluating the systematic use of high oxygen (6 L/min or higher) versus room air or lower oxygen supply in STEMI patients were included. Systematic review with meta-analysis of trials retrieved in July 2020. Six databases were searched. The confidence in the pooled estimates was ascertained through the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Risk of bias was evaluated using the Cochrane risk of bias tool. There were five eligible RCTs (7703 patients). High oxygen supply was associated with a significant risk reduction of short-term mortality [risk ratio (RR) 0.83; 95% confidence interval (CI), 0.70-0.98; I2 = 0%]. Mortality (longest follow-up) (RR 0.83; 95% CI, 0.71-0.97; I2 = 0%) and heart failure (RR 0.84; 95% CI, 0.60-1.18; I2 = 0%) did not present a risk reduction. Recurrent MI presented a contradictory result, favouring the lower oxygen protocol (RR 1.47; 95% CI, 0.84-2.56; I2 = 0%). The GRADE analysis was very low. High oxygen supply may be associated with a decrease in short-term mortality in STEMI patients, but the pooled data are not robust enough to allow definitive conclusions.

The association of influenza infection and vaccine with myocardial infarction: systematic review and meta-analysis of self-controlled case series

Introduction: Influenza vaccination may be beneficial in coronary disease patients; however the infection and vaccination are associated with acute inflammation, a trigger of cardiovascular events. We aimed to review the risk of myocardial infarction (MI) associated with Influenza infection and the safety of vaccination in self-controlled case series (SCCS).Methods: We performed a systematic review with meta-analysis of SCCS studies to evaluate the risk of MI associated with Influenza infection/vaccination. Database search was performed in August/2018. The data were reported using the incident rate ratio (IRR) and 95% confidence interval (95%CI).Results: three studies for Influenza infection and two studies for Influenza vaccination were eligible. The risk of MI following an Influenza infection was significantly increased in the first 3 days (IRR 5.79; 95%CI: 3.59-9.38) and between 4-7 days (IRR 4.52; 95%CI: 2.80-7.32). In the first 4 weeks following the Influenza vaccination, there was a significant decrease of MI risk (IRR 0.84, 95%CI: 0.78-0.91).Conclusions: Short-term MI risk in Influenza infection is significantly increased, with a low-to-moderate confidence in the pooled evidence. The Influenza vaccine was safe regarding the short-term risk for MI, and the risk reduction is possibly related to a healthy period bias.