Patients with infective endocarditis complicated by heart failure (HF) who undergo valvular surgery had lower in-hospital and one-year mortality rates, researchers report in the Nov. 23 issue of the Journal of the American Medical Association. Yet less than two-thirds of patients with HF underwent surgery, the authors found.

HF is a common complication of infective endocarditis, with occurrence rates in the U.S. as high as 40 percent. HF is associated with in-hospital mortality rates of 15 to 20 percent, and one-year mortality rates of 40 percent. Guidelines by the American College of Cardiology, the American Heart Association and the European Society of Cardiology recommend surgery as a treatment for infective endocarditis patients with HF complications, Todd L. Kiefer, MD, PhD, of the Duke University Medical Center in Durham, N.C., and colleagues wrote. But results from studies examining surgery’s use and benefits have been conflicting.

In an attempt to clarify the issue, Kiefer and colleagues conducted analyses using the International Collaboration on Endocarditis-Prospective Cohort Study, a multicenter study that enrolled 4,166 patients with definite infective endocarditis between June 2000 and December 2006. They designed the study to meet three objects: to identify variables associated with HF in this patient population; determine in-hospital and one-year mortality rates; and examine the use of surgery as a treatment.

Of that cohort, they excluded 91 patients whose HF status was unknown and then divided the remainder into an HF group (1,359 patients) and a no HF group (2,716 patients). The HF group also was categorized by NYHA Class I-IV.  Both groups were further analyzed to determine surgery status. They used additional case reports, medical records and death records to track longer-term outcomes.

They found that 33 percent of the infective endocarditis patients had HF, with 2.7 percent NYHA Class I, 15.1 percent Class II, 28.7 percent Class III, 38 percent Class IV and 15.5 percent unspecified. Patients with HF were more likely to be older, have transferred from another hospital, had a healthcare-associated infection and have a new or worsening left-sided valvular regurgitation. In the HF group, 61.7 percent of patients underwent valvular surgery during their initial hospitalization compared with 43 percent of the no HF group.

“Our finding that nearly one-third of patients with HF and high surgical propensity did not have surgery emphasizes the need for such multidisciplinary, guideline-based management of infective endocarditis,” the authors wrote.

HF complications in this patient population were associated with higher in-hospital mortality, 29.7 percent for the HF group compared with 13.1 percent for patients with no HF. Median duration of the hospitalization was similar for both groups, though.

HF patients who underwent surgical therapy were more likely to survive in-hospital and one year later compared with HF patients who did not undergo surgery, with an unadjusted in-hospital mortality rate of 20.6 vs. 44.7 percent, respectively. Patients treated with surgery had a one-year mortality rate of 29.1 percent compared with 58.4 percent for patients treated with medical therapy alone.

“In the current study, the association between surgery and survival for HF in patients with infective endocarditis was apparent across the spectrum of HF severity,” Kiefer and colleagues pointed out. “Although the relationship with absolute mortality risk reduction was greater for patients with advanced NYHA class III or IV symptoms, an association with lower mortality was also present for patients with NYHA Class I or II symptoms.”

The authors acknowledged limitations that may affect study results. Physicians at each center determined diagnoses and HF severity, which may lead to variability and potential bias. Data did not include time of HF onset, surgery was not randomized, and the association between surgical time and outcomes was not evaluated. They noted that a randomized trial would be ethically problematic in this patient population.

“Valvular surgery is strongly associated with lower in-hospital and one-year mortality in patients with HF but is performed in only 62 percent of cases,” they concluded. “Additional studies are needed to better risk-stratify patients with infective endocarditis and HF and optimize the use of surgery for this serious condition.”