Lactobacillus levels and prognosis of patients with acute myocardial infarction.

To 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.Consecutive 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.The 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).This 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.