Incidence, characteristics and outcomes of Infective Endocarditis with low inflammatory markers

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Bacterial infective endocarditis (IE) is rarely suspected in patients with a low C-reactive protein (CRP) concentration. Aims To address the incidence, characteristics and outcome of left-sided valvular IE with low CRP concentration. Methods This was a retrospective analysis of cases of IE discharged from a tertiary hospital between December 2013 and september 2019. The 10% lowest CRP concentration (<25mg/L) was used to define low CRP concentration. Right-sided cardiac device-related IE, non-bacterial IE, sequelar IE and IE previously treated by antibiotics were excluded. Results Of the 105 patients, 16 (16%; median age 41 [15–76] years) had definite (n = 12) or possible (n = 4) left-sided valvular IE with CRP < 25mg/L (median 14.25 [1.5–24.8] mg/L). The median white blood cell count was 7.7 (4.2–12.5) G/L. The main presentations were heart failure (n = 10; 62%) and stroke (n = 1; 6%). Transthoracic echocardiography (TTE) showed vegetations (n = 12) or isolated valvular regurgitation (n = 4). Overall, nine patients (56%) had severe valvular regurgitation on transoesophageal echocardiography (TOE), and seven patients (43%) underwent cardiac surgery. 68% of patients survived at 1-year follow-up. Bacterial pathogens were documented only in four patients (streptococci, coagulase-negative Staphylococcus, gamella morbillorum) using blood cultures solely , due to lack of disponibility of specific serology / valve culture and/or polymerase chain reaction analysis Conclusions Left-sided valvular IE with limited or no biological syndrome is rare, but is often associated with severe valvular and paravalvular lesions. TOE should be performed in presence of unexplained heart failure, new valvular regurgitation or cardioembolic stroke when TTE is insufficient to rule out endocarditis, even in patients with a low CRP concentration.