Prediction of Symptomatic Embolism in Infective Endocarditis: Construction and Validation of a Risk Calculator in a Multicenter Cohort

Study Questions:

Can a simple calculator be developed to quantify at the time of admission the risk of symptomatic embolism among patients with infective endocarditis?


From 1,022 consecutive patients presenting with a definite diagnosis of infective endocarditis in a multicenter observational cohort study, 847 were randomized into derivation (n = 565) and validation (n = 282) samples. Clinical, microbiological, and echocardiographic data were collected at admission. The primary endpoint was symptomatic embolism that occurred during the 6-month period following the initiation of treatment. The prediction model was developed and validated accounting for competing risks.


The 6-month incidence of embolism was similar in the development and validation samples (8.5% in the two samples). Six variables were associated with embolic risk and used to create the calculator: age, diabetes, atrial fibrillation, embolism before antibiotics, vegetation length, and Staphylococcus aureus. There was an excellent correlation between the predicted and observed embolic risk both in the development and validation samples. The c statistics for the development and validation samples were 0.72 and 0.65, respectively. Finally, a significantly higher cumulative incidence of embolic events was observed in patients with a high predicted embolic risk both in the development (p < 0.0001) and validation (p < 0.05) samples.


The risk of a symptomatic embolism among patients admitted with infective endocarditis can be quantified at admission by a simple and accurate calculator. This calculator might be useful for facilitating therapeutic decisions.


Existing risk criteria for embolization complicating infective endocarditis often are based on observational studies that describe the features of patients and vegetations after embolization has occurred. This study instead examined clinical features at the time of admission, and created (and tested) a risk model for subsequent symptomatic embolization. If validated in other cohorts of patients, and if earlier surgery is shown to reduce embolic risk and improve overall outcomes, then the risk calculator could help guide the timing of intervention among patients with infective endocarditis.

Clinical Topics: Noninvasive Imaging, Echocardiography/Ultrasound

Keywords: Incidence, Risk, Endocarditis, Cardiology, Embolism, Diabetes Mellitus, Echocardiography

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