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14-09-2016 | Interventional cardiology | News | Article

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Risk factors identified for TAVR infective endocarditis

medwireNews: Infective endocarditis following transcatheter aortic valve replacement (TAVR) appears to be more likely if patients are relatively younger, male and have a history of diabetes and moderate-to-severe aortic regurgitation, research shows.

And for these patients who develop infective endocarditis, the prognosis is “poor”, say Josep Rodés-Cabau (Laval University, Quebec City, Canada) and co-researchers, who report an in-hospital mortality rate of 36.0% and a 2-year rate of 66.7%.

“This study confirms the high rate of morbidity and mortality of infective endocarditis after TAVR and provides novel information about the timing, causative organisms, and predictive factors of infective endocarditis in this particular population”, they comment in JAMA.

Among 20,006 patients undergoing TAVR, 250 developed infective endocarditis a median of 5.3 months later, at an incidence of 1.1% per person–year. This is similar to the rate previously reported for surgical valve endocarditis, note Rodés-Cabau and colleagues, despite TAVR being less invasive.

Factors associated with infective endocarditis were assessed in 108 affected patients versus 6290 who did not develop the condition.

The median age of the patients was 80 years, but it was younger patients, aged an average of 78.9 years versus 81.8 years, who had a significantly greater likelihood of infective endocarditis, at a hazard ratio (HR) of 0.97 for every year older.

Unable to provide a clear explanation for this finding, the researchers suggest that “younger patients considered at high or prohibitive surgical risk may exhibit a higher comorbidity burden than their older counterparts.”

Men were also 69% more likely than women to develop the condition, at an average rate of 62.0% versus 49.7%.

As previously suggested, diabetes was a risk factor, occurring in 41.7% of patients with versus 30.0% of those without infective endocarditis, giving an HR of 1.52, and risk was increased further among patients with than without residual moderate-to-severe aortic regurgitation (22.4 vs 14.7%), at a HR of 2.05.

This may be due to the abnormal blood flow, turbulence and high-shear stress associated with aortic regurgitation heightening platelet and fibrin deposition and increasing the likelihood of nonbacterial thrombotic endocarditis, suggests the team.

The researchers therefore recommend “a more aggressive approach by including antibiotic prophylaxis” and add: “Reducing the risk of bacteremia by eradicating unnecessary procedures and reinforcing the preventive measures could be considered for patients with significant aortic regurgitation after TAVR.”

For 52.8% of patients, infective endocarditis was healthcare-associated and among the remaining 47.2%, Enterococcus species and Staphylococcus aureus were the most common micro-organisms isolated, at 24.6% and 23.3%, respectively.

A total of 90 patients with infective endocarditis died while in hospital and this outcome was more common for patients with heart failure (odds ratio [OR]=3.36) and acute kidney injury (OR=2.70), irrespective of surgery, which was performed in 14.8% of patients.

A higher EuroScore was also an indication of death, with every 1% increase in score raising the risk by 1.03%, reflecting “the influence of comorbidities on outcome”, say the researchers.

They conclude that their findings “may help the clinicians identify patients at higher risk and aid in implementing appropriate preventive measures.”

By Lucy Piper

medwireNews is an independent medical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2016

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