I read with great interest the article by Okonta et al. [1], and I think that the discussion should be primarily focused on early surgery in left-sided infective endocarditis (IE) to prevent stroke. The three main indications for early surgery in IE are heart failure, uncontrolled infection and prevention of embolic events [2]. Although embolic stroke is a major cause of morbidity in patients with IE, the value of early surgery in preventing embolic events still remains controversial.
According to the data analyzed by Okonta et al. [1], it is very clear that a vegetation length >10 mm and severe vegetation mobility are the most potent independent predictors of a new embolic event. If we use the term "new embolic event" in relation to the time after the beginning the antibiotic therapy in IE, then the benefits of surgery in preventing embolism may be greatest during the first week of antibiotic therapy. This is because the risk of new embolism is highest during the first days following the initiation of antiobiotic therapy and decreases two weeks thereafter [3].
Although new recommendations of European Society of Cardiology guidelines for IE emphasize the timing of surgery [2], the exact role of early surgical intervention in order to avoid embolic events is still unclear. Vegetation size can be one of the reasons for surgery, but is rarely the only one. In the absence of a previous embolism, surgery is indicated with vegetation length >10 mm and some other predictor of complicated IE (heart failure, uncontrolled infection). Eventually, surgery may be considered in cases with very large (>15 mm) vegetations on the aortic or mitral valve, according to the possibility of valve repair. Cabell et al. [4] have demostrated that in native IE, mitral valve IE is associated with higher risk of embolism than aortic valve IE (OR 3.6; 95% CI 1.1-11.6). That is why earlier surgery should be especially emphasized in the cases of mitral valve vegetations.
Finally, one must keep in mind that the major complications with early surgery are valve dysfunction because of tissue inflammation, and the increased risk of recurrent infection resulting in early prosthetic valve endocarditis [5].
Any current conclusions must be open to continuing review as new data become available to allow more enlightened judgements in preventing the risk of embolism in left-sided IE. Some personal conclusions regarding the indication of early surgery in IE include:
i) vegetation lengths >10 mm associated with one of the following conditions: complicated course of IE (haemodynamic deterioration, uncontrolled infection, neurological complication), severe vegetation mobility located on the mitral valve, valve repair appears feasible immediately after antibiotic therapy is started;
ii) vegetation length >15 mm in aortic or mitral valve with or without other complication.
Conflict of interest: none declared
References
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