The prognosis of infective endocarditis treated with biological valves versus mechanical valves: A meta-analysis

Abstract

Objective: Surgery remains the primary form of treatment for infective endocarditis (IE). However, it is not clear what type of prosthetic valve provides a better prognosis. We conducted a meta-analysis to compare the prognosis of infective endocarditis treated with biological valves to cases treated with mechanical valves.

Methods: Pubmed, Embase and Cochrane databases were searched from January 1960 to November 2016.Randomized controlled trials, retrospective cohorts and prospective studies comparing outcomes between biological valve and mechanical valve management for infective endocarditis were analyzed. The Newcastle-Ottawa Scale(NOS) was used to evaluate the quality of the literature and extracted data, and Stata 12.0 software was used for the meta-analysis.

Results: A total of 11 publications were included; 10,754 cases were selected, involving 6776 cases of biological valves and 3,978 cases of mechanical valves. The all-cause mortality risk of the biological valve group was higher than that of the mechanical valve group (HR = 1.22, 95% CI 1.03 to 1.44, P = 0.023), as was early mortality (RR = 1.21, 95% CI 1.02 to 1.43, P = 0.033). The recurrence of endocarditis (HR = 1.75, 95% CI 1.26 to 2.42, P = 0.001), as well as the risk of reoperation (HR = 1.79, 95% CI 1.15 to 2.80, P = 0.010) were more likely to occur in the biological valve group. The incidence of postoperative embolism was less in the biological valve group than in the mechanical valve group, but this difference was not statistically significant (RR = 0.90, 95% CI 0.76 to 1.07, P = 0.245). For patients with prosthetic valve endocarditis (PVE), there was no significant difference in survival rates between the biological valve group and the mechanical valve group (HR = 0.91, 95% CI 0.68 to 1.21, P = 0.520).

Conclusion: The results of our meta-analysis suggest that mechanical valves can provide a significantly better prognosis in patients with infective endocarditis. There were significant differences in the clinical features of patients receiving a biological valve compared to patients receiving a mechanical valve. A large, multicenter retrospective study included in our meta-analysis suggested that any mortality risk of the biological valve group was significant higher than that of the mechanical valve group. However, the risk was no different after risk was adjusted. So, we thought the reason for this result may be related to the characteristics of the patient rather than valve dysfunction. It is still necessary to future randomized studies to verify this conclusion.

Fig 1. PRISMA flowchart.

Fig 2

(A) Comparison of all-cause mortality between biological valves and mechanical valves. (B) Exclusion of the study with maximum weight altered the results.(C) Comparison of early mortality between biological valves and mechanical valves.

Fig 3. Galbraith plot results indicated studies of Delahaye et al. and Nguyen et al. were located outside the interval.

Fig 4

(A) Subgroup analysis of nine studies in the interval. (B) Subgroup analysis of study design. (C) Subgroup analysis of patients with isolated aortic valve endocarditis. (D) Subgroup analysis of patients with isolated PVE.

Fig 5

(A) Comparison of the recurrence of endocarditis between biological valves and mechanical valves. (B) Comparison of the incidence of reoperation between biological valves and mechanical valves. (C) Comparison of postoperative embolic events between biological valves and mechanical valves.

Fig 6

(A) Funnel plot of studies on all-cause mortality.(B) Egger’s regression test of studies on all-cause mortality.