Complex infective endocarditis with perivalvular abscess and fistulation: two high-risk cases requiring extensive reconstruction and valve replacement

BACKGROUND: Infective endocarditis (IE) complicated by aortic root abscess, fistulation and multivalve involvement is rare but carries high mortality. Fistulation from the left ventricular outflow tract (LVOT) to the right atrium (RA) represents an exceptionally uncommon sequela due to extensive perivalvular tissue destruction. Early surgical intervention remains crucial, but postoperative outcomes vary widely depending on host factors, organism control and the feasibility of durable reconstruction. CASE PRESENTATION: We report two cases of severe aortic valve endocarditis with aortic root abscess and acquired LVOT-RA fistula. The first patient had native-valve Streptococcus mitis endocarditis and underwent aortic and tricuspid valve replacement with double CardioCel patch repair of the fistula. He recovered after transient renal and hepatic dysfunction and completed six weeks of intravenous ceftriaxone. The second patient had prosthetic aortic valve endocarditis with aortomitral curtain destruction, pseudoaneurysm, severe malnutrition, and tricuspid involvement. He underwent redo sternotomy, aortomitral curtain reconstruction, double patch fistula repair, and triple bioprosthetic valve replacement. Although the initial repair was technically satisfactory, he later developed severe mitral paravalvular regurgitation with recurrent Staphylococcus haemolyticus bacteremia and died after deterioration with sepsis and multiorgan dysfunction. CONCLUSION: These cases illustrate the range of outcomes after complex endocarditis surgery. Patch-based reconstruction may be appropriate when radical debridement leaves sufficient tissue for secure prosthetic seating, whereas extensive prosthetic infection, malnutrition, recurrent bacteremia, and tissue friability increase the risk of late mechanical failure.