The association between infections and acute coronary syndromes has been the subject of interest for many years. Recent evidence demonstrates an increased risk of cardiovascular events in patients presenting with infections, and infection can also occur as a complication of a hospitalisation for an acute coronary syndrome. In this commentary, Alexandre Quadros and Renato Lopes review the available data for infection in patients with acute coronary syndrome (specifically ST-segment elevation myocardial infarction; STEMI) and discuss management options.
Our group recently reported a 29% mortality rate among STEMI patients who presented with a serious infection during the hospitalisation and who were enrolled in a randomised clinical trial. However, contemporary studies assessing the serious infections in unselected STEMI patients undergoing primary percutaneous intervention (PCI) are scarce.
In our study,1 we enrolled consecutive STEMI patients in a tertiary referral centre in south of Brazil, (Instituto de Cardiologia do Rio Grande do Sul) and patients with serious infections were compared with those without infection. We also assessed the prevalence, characteristics and outcomes of patients with community- vs. hospital-acquired infections. This study was the Master Degree thesis of our fellow Pedro Piccaro de Oliveira, who was the first author of the paper.
During the study period, 1,486 patients were included. Serious infection was present in 58 individuals (3.9%): 30 patients (2%) had community-acquired infections and 28 patients (1.9%) had hospital-acquired infections. Respiratory infection was responsible for 82% of the serious infections. Patients with serious infection were older, had more comorbidities and worse angiographic results of the primary PCI procedure when compared to those without serious infections.
After multivariable adjustment, serious infection was associated with an approximate 10-fold risk of 30-day mortality. Patients with community-acquired infection more often had a history of smoking, Killip III/IV class myocardial infarction on hospital admission, worse primary PCI and angiographic results than patients with hospital-acquired infections. However, no differences were seen in 30-day major cardiovascular outcomes between these groups of patients.
The unique findings of our study are that STEMI patients who have a serious infection have significantly worse primary PCI outcomes than STEMI patients without an infection and that the incidence of community-acquired infection, in this setting, is similar to that of hospital-acquired infection. Additionally, we found that 4% of STEMI patients—in this contemporary unselected series—had a serious infection (a similar prevalence to that seen in previous studies) and that patients with an infection were associated with a 10-fold higher rate of 30-day mortality rate compared with those without an infection. We believe our results should make both physicians and interventionists be vigilant about the high risk of this association and also might help patient stratification in this setting.
As we reported in the American Heart Journal,1 recent evidence suggests that a more potent antiplatelet regimen—such as ticagrelor (Brilinta, AstraZeneca)—rather than clopidogrel could be of benefit for patients with acute coronary syndrome and serious infection. According to the results of PLATO (ticagrelor versus clopidogrel in patients with acute coronary syndromes), ticagrelor was associated with fewer deaths following pulmonary infections and sepsis.
While we cannot conclude from our data that community-acquired infections contribute to “trigger” plaque erosion or rupture and myocardial infarction, recent evidence indicates that infections— particularly pneumonia—can trigger an acute coronary syndrome.
Future observational studies on this field should try to better evaluate the mechanisms behind our findings. Also, randomised clinical trials assessing the impact of early antibiotic therapy in those at very high risk or with high likelihood of having an associate infection would be important to address the very high mortality rates of patients with a STEMI complicated by serious infection.
- de Oliveira. American Heart Journal 2016. Epub.
Renato Lopes is at Duke Clinical Research Institute, Duke University Medical Center, Durham, USA and Alexandre S Quandros is at Instituto de Cardiologia Do Rio Grande Do Sul/Fundação, Universitária de Cardiolgia, Porto Alegre, Brazil