title: Contribution of extracardiac factors to the inconsistency between plasma B-type natriuretic peptide levels and the severity of pulmonary congestion on chest X-rays in the diagnosis of heart failure.
abstract: OBJECTIVE
  Chest X-rays and plasma B-type natriuretic peptide (BNP) levels are useful for diagnosing congestive heart failure. However, the relationship between plasma BNP levels and pulmonary congestion on chest X-rays often seems inconsistent. Extracardiac factors can directly alter plasma BNP levels, independent of cardiac function. In the present study, we examined the clinical factors that impact the diagnosis of heart failure by using chest X-rays and plasma BNP levels.
  
  
  RESULTS
  This study comprised 459 consecutive patients who were admitted to the cardiovascular division of our hospital for any reason and in whom chest X-rays and plasma BNP levels were measured within 12 hours after admission. The approximate BNP value associated with pulmonary congestion that was detectable by chest X-rays was 143 pg/mL, but this value was influenced by renal function, age, and body mass index (BMI). Furthermore, we examined the effect of these three extracardiac factors on plasma BNP levels in each stage of pulmonary congestion. We found that renal dysfunction and advanced age increased the plasma BNP levels, whereas a high BMI decreased the levels, and that the effect of BMI on plasma BNP levels was greater for severe heart failure.
  
  
  CONCLUSIONS
  Extracardiac factors should be considered when the relationship between the plasma BNP levels and the severity of pulmonary congestion on chest X-rays seems inconsistent. In particular, low levels of plasma BNP in patients with a high BMI should be carefully considered to avoid underestimating the degree of heart failure.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, The Jikei University School of Medicine, Japan.
authors.forename: Tokiko
authors.initials: T
authors.lastname: Nakane
authors.forename: Makoto
authors.initials: M
authors.lastname: Kawai
authors.forename: Kimiaki
authors.initials: K
authors.lastname: Komukai
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Kayama
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Matsuo
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Nagoshi
authors.forename: Kosuke
authors.initials: K
authors.lastname: Minai
authors.forename: Taro
authors.initials: T
authors.lastname: Date
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ogawa
authors.forename: Hidenori
authors.initials: H
authors.lastname: Yagi
authors.forename: Michihiro
authors.initials: M
authors.lastname: Yoshimura
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D011654:Pulmonary Edema / Q000097:blood* / Q000000981:diagnostic imaging*; D011859:Radiography; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D020097:Natriuretic Peptide, Brain