Prognostic relevance of pericardial effusion in STEMI patients treated by primary percutaneous coronary intervention: a 10-year single-centre experience

Background: Pericardial effusion is frequent in the acute phase of ST-segment elevation myocardial infarction. However, its prognostic role in the era of primary percutaneous coronary intervention is not completely understood. Methods: We investigated the association between pericardial effusion, assessed by transthoracic echocardiography, and survival in a large cohort of ST-segment elevation myocardial infarction patients treated with primary percutaneous coronary intervention, enrolled in the Trieste primary percutaneous coronary intervention registry from January 2007 to March 2017. Multivariable analysis and a propensity score approach were performed. Results: A total of 1732 ST-segment elevation myocardial infarction patients were included. Median follow-up was 45 (interquartile range 19-79) months. Pericardial effusion was present in 246 patients (14.2%). Thirty-day all-cause mortality was similar between patients with and without pericardial effusion (7.8% vs. 5.4%, P=0.15), whereas crude long-term survival was worse in patients with pericardial effusion (26.2% vs. 17.7%, P <= 0.01). However, at multivariable analyses the presence of pericardial effusion was not associated with long-term mortality (hazard ratio 1.26, 95% confidence interval 0.86-1.82, P=0.22). Matching based on propensity scores confirmed the lack of association between pericardial effusion and both 30-day (hazard ratio 1, 95% confidence interval 0.42-2.36, P=1) and long-term (hazard ratio 1.14, 95% confidence interval 0.74-1.78, P=0.53) all-cause mortality. Patients with pericardial effusion experienced a higher incidence of free wall rupture (2.8% vs. 0.5%, P<0.0001) independently of the entity of pericardial effusion. Conclusions: In acute ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention, the onset of pericardial effusion after ST-segment elevation myocardial infarction is not independently associated with short and long-term higher mortality. Free wall rupture has to be considered rare compared to the fibrinolytic era and occurs more frequently in patients with pericardial effusion, suggesting a close monitoring of these patients in the early post-primary percutaneous coronary intervention phase.