Thrombocytopenia, a new marker of bad prognosis in patients with infective endocarditis

Abstract

Aim: Thrombocytopenia in patients with sepsis has been described as a marker of bad prognosis. Our purpose was to analyze if the presence of thrombocytopenia has a prognostic impact in patients with left-sided infective endocarditis (IE). Methods: We analyzed 698 consecutive episodes of IE prospectively recruited in three referral hospitals between 1996 and 2011. They were classified in two groups: Group I (n=213) episodes of IE who had thrombocytopenia in blood analysis at admission; and Group II (n=485) those who did not have it. Thrombocytopenia was defined as a platelet count below 150000/μl. Results: The age and gender distribution were similar in both groups. Regarding to comorbidities, diabetes (25.4% vs. 18.3%, p=0.03), chronic anemia (24.5% vs. 17.6%, p= 0.03) and immunosuppression (11.8% vs. 4.5%, p<0.001) were more frequent in Group I. We found a greater percentage of prosthetic valves in Group II, while patients without any previous cardiopathy were more prevalent in Group I (29.6% vs. 21.6%, p=0.02). S. aureus (28.6% vs. 10.9%, p<0.001) and Gram negative bacilli (8% vs. 3.1%, p=0.004) were more frequently isolated in Group I, were S. viridans (8% vs. 15.1%, p=0.01) and culture negative IE (10.3 vs. 16.3, p=0.04) were more common in Group II. Clinical presentation with neurological (p<0.001), renal (p=0.05), cutaneous (p<0.001) manifestations and septic shock (12.2% vs. 3.5%, p<0.001) at admission were more frequent in Group I. These patients showed also more frequency of hemorrhagic skin lesions (11% vs. 4%, p=0.002), splenomegaly (14.2% vs 7.4%, p=0.005) and coma (5.6% vs. 0.8%, p<0.001). Presence of pseudoaneurysms were more frequently found in Group II (12.2% vs. 18.9%, p=0.03). There were no differences in other echocardiographic findings (valvular insufficiency, presence and size of vegetations). During hospitalization, persistent signs of infection (44.5% vs. 31.8%, p=0.001) and septic shock were more frequent in Group I (27% vs. 13.5%, p<0.001). The need of surgery was similar in both groups (53.5% vs. 56.1%, p=0.535), but much higher mortality was observed in patients with thrombocytopenia (40.4% vs. 25.3%, p<0.001). Conclusions: Thrombocytopenia at admission of patients with IE identifies a highest risk group. Causative microorganisms are more virulent in this group. These patients develop septic shock more frequently and showed higher mortality.