Early Surgery for Prosthetic Valve Endocarditis

In approximately 3% to 6% of patients who undergo valve implementation, prosthetic valve endocarditis (PVE) occurs within 5 years of the procedure. In addition, PVE has been associated with significant morbidity and mortality. Guidelines recommend surgical intervention with debridement and valve replacement for patients with complications that may include valve dysfunction, dehiscence, heart failure, cardiac abscesses, or persistent bacteremia.

According to researchers, the guidelines are “based largely on expert opinion and limited observation data.” Conflicting data has emerged from studies that compared survival of patients undergoing surgery with those treated with medical therapy for PVE.

Noting that no randomized studies of surgery for PVE had been performed, the researchers recently conducted a study designed to examine in-hospital and 1-year mortality in patients with PVE who undergo valve replacement compared with patients who receive medical therapy alone, after controlling for survival and treatment selection bias. Study results were reported in JAMA Internal Medicine [2013;173(16):1495-1504].

The ICE-PCS (International Collaboration on Endocarditis-Prospective Cohort Study) is a prospective, multicenter, international registry of patients with infective endocarditis (IE). The researchers collected data based on standard definitions between January 1, 2000, and December 31, 2006, from 64 sites in 28 countries.

Inclusion criteria for the study cohort were patients diagnosed with definite PVE based on the modified Duke criteria. Exclusion criteria included native and nonnative valve IE (pacemaker IE), receipt of surgery before admission, and missing values for sex, receipt and/or date of surgery, length of initial hospitalization, in-hospital death, and death at 1-year follow-up.

The ICE-PCS cohort included 4166 patients with definite left- or right-side IE. Of these, 1025 had definite PVE and met the eligibility criteria for this study. Of that group, 47.8% (n=490) underwent early surgery and 52.2% (n=535) received medical therapy alone.

In the unadjusted analysis, compared with medical therapy alone, early surgery was associated with lower in-hospital mortality. Following adjustment for treatment selection bias and 1-year mortality, early surgery remained strongly associated with lower mortality (in-hospital mortality: hazard ratio [HR], 0.44 [95% confidence interval (CI), 0.38-0.52] and 1-year mortality: HR, 0.57 [95% CI, 0.49-0.67]).

The lower mortality associated with surgery did not persist after adjustment for survivor bias (in-hospital mortality: HR, 0.09 [95% CI, 0.76-1.07] and 1-year mortality: HR, 1.04 [95% CI, 0.8-1.23]).

The researchers divided the cohort into 5 subgroups based on the predicted probability of surgery (without regard to actual treatment received by the patient). This subdivision created 5 groups with 205 patients who were comparable in clinical characteristic and probability of surgery, but differed by the treatment received. Patients in the fifth quintile had a higher predicted probability of surgery (range, 68.5%-98.2%) versus those in the first quintile (range, 5.2%-27.5%). At 1-year follow-up, reduced mortality with surgery was observed in the fourth (24.8% vs 42.9%) and fifth (27.9% vs 50.0%; P=.007) quintiles of surgical propensity.

In conclusion, the researchers stated, “Prosthetic valve endocarditis remains associated with a high 1-year mortality rate. After adjustment for differences in clinical characteristics and survival bias, early valve replacement was not associated with lower mortality compared with medical therapy in the overall cohort. Further studies are needed to define the effect and timing of surgery in patients with PVE who have indications for surgery.”