This meta-analysis demonstrated that early and late surgery in patients with IE complicated with CI were associated with similar rates of all-cause mortality and recurrence. IE remains a major illness with a high mortality secondary to complications including congestive heart failure and neurologic events [18, 19]. Current guidelines recommend early surgery when specific parameters are met, such as recurrent emboli or large vegetation [20, 21]. A previous meta-analysis demonstrated that early surgery was associated with significant reduction in all-cause mortality in patients with IE [22]. However, early surgery might have an opposite effect after IE is complicated with neurologic events, since anticoagulation during cardiopulmonary bypass can turn an ischemic stroke into a hemorrhagic stroke, or exacerbate a stroke due to hypotension during operation. Current guidelines recommend delaying surgery for 3 to 4 weeks in IE patients with major or hemorrhagic stroke [23, 24]. Similarly, a recent meta-analysis showed that early surgery was associated with increased mortality and neurological exacerbation in patients with hemorrhagic stroke as well as ischemic stroke [5]. However, they were unable to analyze the outcomes beyond the perioperative period owing to scarcity of data on mid- to long-term outcomes.
This is the first meta-analysis comparing the outcomes beyond the perioperative period between early and late surgery in patients with IE complicated with CI. Although previous meta-analyses demonstrated worse perioperative mortality with early surgery than that with late surgery [5, 22], our results showed similar mortality and recurrence rates. Furthermore, leave-one-out sensitivity analysis showed that eliminating any one of those studies did not change the outcomes, suggesting that our findings were not derived from any single study. This could be attributed the fact that 40–60% of patients with IE develop heart failure because of structural damage [25, 26], and early surgery might prevent the development of heart failure caused by progressive regurgitation [27]. Therefore, although early surgery might increase preoperative mortality and neurologic complications in patients with IE complicated with neurologic events [5], it might have a positive effect on long-term outcomes by preserving cardiac function.
Our analysis has several limitations. First, our study comprised observational studies and is therefore subject to possible selection bias. Second, we did not analyze perioperative outcomes, since a previous meta-analysis including 27 observational studies [5] was conducted and the perioperative outcomes were thoroughly analyzed. Although they could not analyze the outcomes beyond the perioperative period, we were able to analyze them by extracting the HR from the Kaplan-Meier curve [6]. Third, the definition of early surgery varied among the studies, ranging from 3 to 14 days. Finally, there might be survivor bias in the late surgery group, and we could not assess how many patients died while waiting for the surgery.