Clinical Status Quo of Infective Endocarditis in a University Hospital in Japan: A Single-hospital-based Retrospective Cohort Study

Abstract

Objective No research on infective endocarditis (IE) concerning populations of more than 40 patients from all departments of the hospitals they may have visited in Japan has been conducted since 2000. The present study clarified the status quo of IE in a university hospital in Japan. Methods Data of inpatients of Saga University Hospital with definite IE from September 2007 to August 2017 were retrospectively analyzed. Patients Records of inpatients with diagnosed IE admitted to any department were scrutinized; those with "definite IE" according to the modified Duke's criteria comprised the study cohort. Results The study cohort was 74 patients with a median age 66.5 years old. Symptoms within 2 months before the first visit to our hospital included a fever (73.0%), general malaise (33.8%), disturbance of consciousness (24.3%), and dyspnea (24.3%). High-frequency causative microorganisms were Staphylococcus aureus (28.4%), followed by Streptococcus viridans (18.9%) and Enterococcus spp. (6.8%). The most frequently involved valves were the mitral valve (48.6%), followed by the aortic valve (25.7%) and multiple valves (14.9%). Patients without cardiac murmurs accounted for 37.8%, and those without or with only mild valvular disease accounted for 32.4%. The incidence of complications was 93.2%, and high-frequency complications were central nervous system disorder (60.8%), followed by glomerulonephritis (45.9%) and extracranial embolism (36.5%). Conclusion The incidences of IE without cardiac murmurs and IE without or with only minor valvular disease were higher than those values previously reported in 2000 in Japan. When IE is suspected clinically, clinicians must check thoroughly for common complications, even in patients without cardiac murmurs or valvular disease.

Keywords: cardiac murmur; clinical manifestation; complication; embolism; infective endocarditis; valvular disease.

Figure 1.

Inclusion criteria. One hundred and 10 inpatients diagnosed with IE in Saga University Hospital from September 2007 to August 2017 were identified from the International Statistical Classification of Diseases and Related Health Problems-10 (ICD-10) (code number I-330). Two doctors of the Department of General Medicine in our hospital re-checked these patients’ data according to the modified Duke’s clinical criteria and found that 70 of them had “definite IE” and 40 “probable IE” or “not IE”. Cardiac valve surgery was performed in 31 patients in the “definite IE” group and 9 in the “probable IE” or “not IE” groups, after which 30 patients were diagnosed with “definite IE” group and 4 with “probable IE” or “not IE” according to the modified Duke’s pathological criteria. All 74 patients diagnosed with “definite IE” according to either the modified Duke’s clinical or pathological criteria were enrolled and analyzed in the present study.

Figure 2.

Cardiac murmurs and valvular disease. Findings of cardiac auscultation were recorded in the medical charts of 73/74 patients, and findings of echocardiography were recorded for all study patients. No cardiac murmurs were detected in 28 patients (37.8%), and no valvular disease was detected in 13 (17.6%) by either TTE or TEE, resulting in 24 patients (32.4%) being classified as having no or only grade I valvular disease. Detected valvular diseases consisted of mitral regurgitation (47, 63.5%), aortic regurgitation (28, 37.8%), tricuspid regurgitation (21, 28.4%), and pulmonary regurgitation (4, 5.4%), and valvular diseases more severe than grade I were found in 33 (44.6%), 23 (31.1%), 18 (24.3%), and 2 (2.7%) of these patients, respectively.