Despite medical advances, IE remains a disease with high morbidity and mortality. Cerebral embolism is one of the most common and devastating complications of IE. Early surgery for patients with surgical indications aims to avoid this complication. Recent ACC/AHA and ESC/EACTS guidelines emphasize that surgery should not be delayed once a surgical indication has been established. However, when addressing vegetations, these guidelines consider only the size of vegetations as a criterion for surgical indication. Furthermore, other factors, such as the location of the vegetation, a history of prior stroke, or the type of microorganism causing IE, may also contribute to the mechanism of cerebral embolism. Additionally, the 10 mm vegetation size threshold has persistently been used to assess embolic risk in IE patients, yet variables such as multiple vegetation locations or the importance of the affected valve have never been adequately examined.
The purpose of this study was to assess the size, multiplicity, and position of vegetations and their association with cerebral embolism and long-term mortality in IE patients. A total of 419 patients with IE admitted to a single institution from November 2005 to August 2017 were retrospectively reviewed, of whom 273 underwent surgery. The primary endpoint was all-cause mortality, and the secondary endpoint was cerebral embolism. Cox regression analysis and logistic regression were performed to identify risk factors for 30-day mortality, long-term mortality, and cerebral embolism. Age (HR = 1.02), renal failure (HR = 4.21), surgery (HR = 0.31), and a high APACHE II score (HR = 1.08) were associated with increased long-term mortality. However, vegetation size, multiplicity, and position were not significantly associated with long-term mortality. Still, a mitral vegetation size greater than 10 mm (OR = 2.25) was an independent risk factor for cerebral embolism.
The authors conclude that mitral vegetation size over 10 mm is a risk factor for cerebral embolism, and for this group, early surgery could be considered to prevent cerebral embolism.
COMMENTARY:
Today, IE remains one of the greatest challenges faced by different medical specialists, not only due to its diagnostic difficulty from its varied clinical presentations but also due to the complexity of its medical and surgical treatment. The in-hospital mortality rate of IE ranges between 15% and 20%, with one-year mortality close to 40% in many series. These figures contrast with the excellent outcomes in this study by Song et al., with a 30-day mortality of 8.8% and long-term mortality of 29.1% after a mean follow-up of 61.5 months. In the last decade, the trend has leaned towards earlier surgical intervention in patients with IE who meet the appropriate criteria. The three main reasons for early surgery are heart failure, uncontrolled infection, and embolism prevention. Scientific evidence supporting early surgery for IE with large vegetations to improve survival is limited, mainly based on a small randomized study and a recent meta-analysis.
Song et al., through their study of 419 IE patients with a mean follow-up of over five years, shed light on the implications of certain vegetations for cerebral embolism and long-term mortality. Interestingly, the increase in these complications was not associated with multiple vegetation locations or vegetations on the aortic valve. However, mobile vegetations larger than 10 mm located on the mitral valve posed a significant risk of stroke. The latest ACC/AHA and ESC/EACTS guidelines for IE precisely use the criteria of a vegetation >10 mm, mobile vegetation, and particularly involvement of the left heart chambers to decide on an indication for early surgery. The results of this study align with these societies’ recommendations, thereby adding evidence to define which patients might benefit from early surgery for IE.
One limitation of the study, aside from its retrospective nature, is the unknown incidence of subclinical cerebral embolism, as brain imaging was only performed for patients presenting neurological symptoms.
As often, reality is far more complex than theory, and an individualized study of each case is essential to decide which patients to operate on and, more importantly, when. Numerous variables must be considered before determining which patients to intervene early, including associated comorbidities; patient frailty and baseline status; surgical risk; time since antibiotic initiation; absence of heart failure or valve destruction; surgical factors such as aortic calcification, coagulation status, and other factors. In fact, 51 patients meeting surgical criteria per guidelines were not operated on due to reasons such as multiorgan failure or severe comorbidities. From now on, however, the finding of a large, mobile vegetation, especially on the mitral valve, should be more heavily weighed in our mental algorithm for decision-making in patients with IE surgical criteria.
REFERENCE:
Song SJ, Kim JH, Ku NS, Lee HJ, Lee S, Joo HC, et al. Vegetation size, multiplicity, and position in patients with infective endocarditis. Ann Thorac Surg. 2022 Dec;114(6):2253-2260. doi: 10.1016/j.athoracsur.2021.10.071.
