The three indication of surgical procedure recommended at 2015 ESC Guidelines were as follow: I) TV vegetations > 20 mm and recurrent septic pulmonary emboli with or without concomitant right heart failure; (II) IE caused by microorganisms that are difficult to eradicate or bacteremia for at least 7 days despite adequate antimicrobial therapy; and (III) Right heart failure secondary to severe TR with poor response to diuretic therapy [1]. Although the lesion is less than 20 mm, this patient is indicated to surgery due to right heart failure secondary to severe TR and poor response to any medical therapy.
There were different surgical approaches of tricuspid valve IE. The European guideline suggested that valve repair is favored than replacement whenever possible without significant destruction [1]. However, in this patient, all of the anterior chordae tendineae were rupture during operation. It’s hard to repair and the patient’s condition could not tolerant one more repair after failure, so tricuspid valve replacement was conducted. Since September 1970, Arbulu et al. reported several right-sided endocarditis with heroin addiction and they received tricuspid valvulectomy without replacement [5]. Although the acceptable outcome was concluded, some patients required further prosthetic heart valve insertion to control medically refractory right-sided heart failure and the others may lead to severe and permanent impairment of right ventricular function. Therefore, the application of valvulectomy without replacement is not that popular in our country.
Tricuspid valve IE complicated by multiple lung abscesses is rare. Yoshimoto et al. [6] first reported the case of a 21-year-old intravenous drug addicted male with right-sided IE complicated by bilateral lung multiple consolidations. However, the culture results were not reported.
Demin et al. [7] further reviewed 100 intravenous drug users with IE, of whom 65 had positive blood cultures. Among these, 46 were positive for S. aureus and only one was positive for A. baumannii complex. In this study, four cases were complicated by lung abscesses, but no abscess culture was obtained and the blood culture results of these four patients were unclear.
In Taiwan, Liu et al. [8] treated an 86-year-old right-sided IE patient with daptomycin. After 5 days of antibiotic treatment, multiple right lower lung abscesses were found. Sputum and blood cultures were negative. The lung abscesses resolved on chest X-ray after linezolid treatment for 10 days. Chen et al. [9] reported the case of a 21-year-old male with tricuspid valve IE and bilateral multiple lung abscesses, with a blood culture positive for methicillin-susceptible S. aureus.
Although some previous studies have reported IE complicated by lung abscesses, no abscess pathogen was reported. Most of these patients had a negative blood culture due to antibiotic treatment for a few days. We believe that these patients were not merely infected by S. aureus translocation. Ercan et al. [10] reported the case of a 24-year-old postpartum female with methicillin-resistant S. aureus tricuspid valve IE who underwent tricuspid valve replacement. Postoperative chest CT revealed bilateral multiple lung abscesses and repeated blood cultures yielded Pseudomonas aeruginosa.
To the best of our knowledge, ours is the first study in which lung abscess cultures were obtained results showed A. baumannii complex and C. albicans. We assumed that most of these lung abscesses were not infected by the previous IE pathogen. The pathogenesis is unclear. It is possible that this patients’ abscesses were acquired from ventilator-associated pneumonia (VAP) and make sense of these pathogens. However, the frequency of combined A. baumannii complex and fungi is not that common. The use of oxacillin or vancomycin is mostly ineffective to cover those pathogens. The antibiotic covered Gram-negative bacteria and thoracoscopic decortication with incision lung abscess is required. Antibiotic coverage for 4 to 6 weeks is adequate for these lung abscess patients.
This report concluded that tricuspid valve IE complicated by multiple lung abscesses and empyema is rare. The pathogen causing the lung abscess is not always compatible with that causing the endocarditis. Thoracoscopic incision of the abscess with 4 to 6 weeks of broad-spectrum antibiotic treatment is effective and safe.