Recurrent Prosthetic Valve Infective Endocarditis Due to Sequential Non-Fermenting Gram-Negative Bacilli after Transcatheter Aortic Valve Implantation in a Patient with Bicuspid Aortic Valve Disease: A Case Report

Abstract

Background: Transcatheter aortic valve implantation has become an established treatment for severe aortic stenosis, including in patients with depressed left ventricular function in whom surgical risk would otherwise be prohibitive. Prosthetic valve endocarditis is an uncommon but serious complication of the procedure, occurring at a rate of roughly one to three per cent per patient-year of follow-up, and is usually caused by staphylococci, streptococci or enterococci. Infection with non-fermenting gram-negative bacilli such as Burkholderia cepacia and Stenotrophomonas maltophilia is exceptionally rare in this setting and is difficult to manage because of the intrinsic multidrug resistance of these organisms.

Case presentation: We describe a 47-year-old man with a congenitally bicuspid aortic valve, severe calcific aortic stenosis and severe left ventricular systolic dysfunction (ejection fraction 15-20%) who underwent transcatheter aortic valve implantation with a 30 mm self-expanding valve after stabilisation of decompensated heart failure. Approximately two months later he was readmitted with a fifteen-day history of fever, chills and cough, one of several blood culture sets grew Burkholderia cepacia, sensitive to co-trimoxazole and meropenem. He was treated for prosthetic valve endocarditis with a six-week course of susceptibility-guided antibiotics, became afebrile, and was discharged with recovery of ejection fraction to 45-50%. Roughly six weeks after completing this treatment he presented again with low-grade fever, fatigue, digital clubbing, hepatosplenomegaly and severe anaemia (haemoglobin 7.6-8.1 g/dL) with a mixed picture suggestive of anaemia of chronic disease and a possible mild haemolytic component. Two blood culture sets grew Stenotrophomonas maltophilia. Echocardiography showed a heterogeneous, thickened perivalvular lesion around the transcatheter prosthesis raising concern for an aortic root abscess, and contrast-enhanced computed tomography demonstrated a splenic infarct consistent with embolisation. He was started on empirical meropenem, vancomycin and gentamicin pending transoesophageal echocardiography and multidisciplinary review, the outcome beyond this point was not captured in the records available for this report.

Conclusions: This case shows that recipients of a transcatheter aortic valve who develop prosthetic valve endocarditis remain at risk of a further, microbiologically unrelated infective episode even after apparently successful treatment. Non-fermenting gram-negative bacilli should be considered in patients who develop recurrent fever after valve intervention, particularly when there has been prior hospitalisation, prolonged antibiotic exposure and indwelling prosthetic material. Species-level identification with formal susceptibility testing is essential, since empirical carbapenem-based regimens may have no activity against Stenotrophomonas maltophilia, and multimodality imaging should be pursued without delay when echocardiographic findings around a transcatheter valve are equivocal.

Keywords: Bicuspid aortic valve, Transcatheter aortic valve implantation, Prosthetic valve endocarditis, Burkholderia cepacia, Stenotrophomonas maltophilia, non-fermenting gram-negative bacilli, Duke-ISCVID criteria, Heart failure with reduced ejection fraction, Case report.