Context Complicated, left-sided native valve endocarditis causes significant
morbidity and mortality in adults. The presumed benefits of valve surgery
remain unproven due to lack of randomized controlled trials.
Objective To determine whether valve surgery is associated with reduced mortality
in adults with complicated, left-sided native valve endocarditis.
Design and Setting Retrospective, observational cohort study conducted from January 1990
to January 2000 at 7 Connecticut hospitals. Propensity analyses were used
to control for bias in treatment assignment and prognostic imbalances.
Patients Of the 513 adults with complicated, left-sided native valve endocarditis,
230 (45%) underwent valve surgery and 283 (55%) received medical therapy alone.
Main Outcome Measure All-cause mortality at 6 months after baseline.
Results In the 6-month period after baseline, 131 patients (26%) died. In unadjusted
analyses, valve surgery was associated with reduced mortality (16% vs 33%;
hazard ratio [HR], 0.43; 95% confidence interval [CI], 0.29-0.63; P<.001). After adjustment for baseline variables associated with
mortality (including hospital site, comorbidity, congestive heart failure,
microbial etiology, immunocompromised state, abnormal mental status, and refractory
infection), valve surgery remained associated with reduced mortality (adjusted
HR, 0.35; 95% CI, 0.23-0.54; P<.02). In further
analyses of 218 patients matched by propensity scores, valve surgery remained
associated with reduced mortality (15% vs 28%; HR, 0.45; 95% CI, 0.23-0.86; P = .01). After additional adjustment for variables that
contribute to heterogeneity and confounding within the propensity-matched
group, surgical therapy remained significantly associated with a lower mortality
(HR, 0.40; 95% CI, 0.18-0.91; P = .03). In this propensity-matched
group, patients with moderate to severe congestive heart failure showed the
greatest reduction in mortality with valve surgery (14% vs 51%; HR, 0.22;
95% CI, 0.09-0.53; P = .001).
Conclusions Valve surgery for patients with complicated, left-sided native valve
endocarditis was independently associated with reduced 6-month mortality after
adjustment for both baseline variables associated with the propensity to undergo
valve surgery and baseline variables associated with mortality. The reduced
mortality was particularly evident among patients with moderate to severe
congestive heart failure.