Abstract: Objective  To analyze the clinical characteristics and prognosis of patients with acute myocardial infarction complicated with pericardial effusion. Methods  This study was a retrospective nested case-control study. Patients with acute myocardial infarction admitted from January 2016 to December 2024 were selected. Patients with concurrent pericardial effusion were assigned to the case group (n=348) and those without pericardial effusion based on age- and gender-matched were assigned to the control group (n=348) at a 1:1 ratio. Clinical data, such as basic information, comorbidities, auxiliary examinations, and prognosis information, were collected and compared between the two groups. A subgroup analysis was conducted within the case group, dividing patients into non-death group (n=280) and death group (n=68) based on survival, and their clinical data were analyzed and compared. Results  During the study period, 6 169 patients were diagnosed with acute myocardial infarction, of which 370 cases were complicated with mild, moderate, and massive pericardial effusion, with a crude incidence rate of 6.00%. A total of 348 patients with pericardial effusion were successfully matched in the case group, while 348 patients without pericardial effusion were in the control group. Compared with the control group, the proportion of pre-hospital cardiogenic shock, admission heart rate, Killip cardiac function grade Ⅲ and Ⅳ proportions, blood glucose, glycosylated hemoglobin A1c (HbA1c), high-sensitivity C-reactive protein (hsCRP), B-type natriuretic peptide (BNP), D-dimer, creatinine, left ventricular end-diastolic diameter (LVEDd), ventricular aneurysm formation, intraoperative thrombotic shadow,  thrombolysis in myocardial infarction (TIMI) score, and GRACE score were recorded, CRUSADE score, Gensini score and SYNTAX score were higher; and the diastolic blood pressure, estimated glomerular filtration rate (eGFR), left ventricular ejection fraction (LVEF) and the proportion of complete coronary angiography during hospitalization were lower (P<0.05). Multifactorial analysis indicates that increased BNP (OR=1.000, P=0.003), decreased albumin levels (OR=0.921, P=0.001), increased creatine kinase myocardial band (CK-MB) peak (OR=1.002, P<0.001), increased hsCRP (OR=1.008, P=0.013), increased LVEDd (OR=2.346, P<0.001), ventricular aneurysm formation (OR=3.004, P=0.006), and atrial fibrillation occurring during hospitalization (OR=2.240, P=0.007) are associated indicators of acute myocardial infarction complicated with pericardial effusion. Compared with the control group, the length of stay, proportion of atrial fibrillation occurring during hospitalization, proportion of abnormal liver function, proportion of abnormal renal function, and proportion of death were higher in the case group, and the differences were statistically significant (P<0.05). Subgroup analysis showed that compared with the non-death group, the age of the patients in the death group, proportion of Killip cardiac function grade Ⅳ, creatinine, BNP, D-dimer, TIMI score, GRACE score, CRUSADE score, SYNTAX score, abnormal renal function, cardiac rupture ratio, atrial fibrillation during hospitalization, malignant ventricular arrhythmia during hospitalization were higher; height, body weight, body mass index, admission diastolic blood pressure, albumin, and eGFR were lower, and the difference was statistically significant (P<0.05). Multifactorial analysis indicates that low weight (OR=0.947, P<0.001), increased creatinine (OR=1.005, P=0.008), atrial fibrillation episodes during hospitalization (OR=3.063, P=0.003), malignant ventricular arrhythmias during hospitalization (OR=3.321, P=0.003), and increased GRACE score (OR=1.028, P<0.001) are associated indicators of mortality in patients with acute myocardial infarction complicated with pericardial effusion. Conclusions  Risk factors for acute myocardial infarction complicated with pericardial effusion include large myocardial infarction, poor heart function, and ventricular aneurysm formation. Low body weight, poor renal function, atrial fibrillation episodes, and malignant ventricular arrhythmias during hospitalization are associated with death in patients with acute myocardial infarction complicated by pericardial effusion, and it should be of particular concern in these patients.

Key words: acute myocardial infarction, pericardial effusion, prognosis, renal function, percutaneous coronary intervention, death