Lactobacillus levels and prognosis of patients with acute myocardial infarction

OBJECTIVETo explore the relationship between Lactobacillus and prognosis of acute myocardial infarction (AMI) patients treated by percutaneous coronary intervention (PCI) and its correlation with clinical parameters.METHODSConsecutive patients with AMI in the coronary care unit of Tianjin Chest Hospital in China who received emergency PCI between July 2017 and December 2018 were enrolled. Subjects’ fecal 16S rDNA gene sequencing data were analyzed and subjects were categorized into low, medium and high level groups according to stool Lactobacillus measurements. The primary endpoints were major adverse cardiac events. Cox regression analysis was used to analyze the relationship between Lactobacillus and prognosis. Spearman correlation analysis and trend tests were used to assess the relationship between Lactobacillus and the clinical indicators.RESULTSThe data of 254 patients were included in the analysis. Mean age was 65.90 ± 11.56 years, and 152 patients (59.84%) were male. Follow-up time was 652 (548.25−753.00) days. Multivariate Cox regression analysis showed a significantly lower risk of major adverse cardiac events in patients with Lactobacillus > 7.1 copies/g [adjusted hazard ratio (HR) = 0.216, 95% CI: 0.094−0.493,P < 0.001] compared to patients with Lactobacillus ≤ 3.6 copies/g. Statistically significant differences were shown in ST-segment elevation myocardial infarction (STEMI) (HR = 0.217, 95% CI: 0.085−0.551, P = 0.001). Lactobacillus was a protective factor for male smokers aged over 60 years whose brain natriuretic peptide was over 1,000 pg/mL. Spearman correlation analysis showed that Lactobacillus correlated negatively with white blood cells, neutrophils, high-sensitivity C-reactive protein, TroponinT, creatine kinase, creatine kinase-MB and brain natriuretic peptide (downward trend), and correlated positively with left ventricular ejection fraction (upward trend). CONCLUSIONSThis study is the first to reveal the correlation between Lactobacillus and inflammation and myocardial damage after STEMI. STEMI patients, especially male smokers aged over 60 years with severe impairment of cardiac function, have better outcomes with high levels of Lactobacillus, suggesting new therapeutic strategies for improving the prognosis and quality of life of AMI patients.

With the aging of society and changes in life style, the incidence of acute myocardial infarction (AMI) is increasing year by year, which has become the main cause of death worldwide and poses a serious threat to human health.^[1] Recently, however, the success rate of AMI rescue has significantly improved, and the rate of death and disability has decreased. The mortality of patients receiving percutaneous coronary intervention (PCI) and optimized drug therapy remain as high as 7% to 18% within one year.^[2,3] New treatments to improve the prognosis and the quality of life of AMI patients are essential. Recently, increased attention is being given to the relationship between gut microbiota and cardiovascular diseases.^[4–6] Our previous study found that the abundance of Lactobacillaceae in the stool of acute coronary syndrome (ACS) patients was significantly decreased.^[7] Also, animal experiments have confirmed that Lactobacillus has the effects of anti-inflammation, regulating blood lipids and improving cardiac injury after myocardial infarction (MI).^[8–10] Therefore, we speculated that the level of Lactobacillus may be associated with the prognosis of patients with AMI. The purpose of this study was to quantitatively analyze the association between Lactobacillus and outcomes of AMI patients treated by emergency PCI, as well as the relationship between Lactobacillus and inflammation, myocardial injury and other biomarkers, and to evaluate the effect of Lactobacillus on long-term prognosis to provide new ideas for early and long-term clinical intervention.