title: Risk of constrictive pericarditis after acute pericarditis.
abstract: BACKGROUND
  Constrictive pericarditis (CP) is considered a rare, dreaded possible complication of acute pericarditis. Nevertheless, there is a lack of prospective studies that have evaluated the specific risk according to different etiologies. The aim of this study is to evaluate the risk of CP after acute pericarditis in a prospective cohort study with long-term follow-up.
  
  
  RESULTS
  From January 2000 to December 2008, 500 consecutive cases with a first episode of acute pericarditis (age, 51±16 years; 270 men) were prospectively studied to evaluate the evolution toward CP. Etiologies were viral/idiopathic in 416 cases (83.2%), connective tissue disease/pericardial injury syndromes in 36 cases (7.2%), neoplastic pericarditis in 25 cases (5.0%), tuberculosis in 20 cases (4.0%), and purulent in 3 cases (0.6%). During a median follow-up of 72 months (range, 24 to 120 months), CP developed in 9 of 500 patients (1.8%): 2 of 416 patients with idiopathic/viral pericarditis (0.48%) versus 7 of 84 patients with a nonviral/nonidiopathic etiology (8.3%). The incidence rate of CP was 0.76 cases per 1000 person-years for idiopathic/viral pericarditis, 4.40 cases per 1000 person-years for connective tissue disease/pericardial injury syndrome, 6.33 cases per 1000 person-years for neoplastic pericarditis, 31.65 cases for 1000 person-years for tuberculous pericarditis, and 52.74 cases per 1000 person-years for purulent pericarditis.
  
  
  CONCLUSIONS
  CP is a relatively rare complication of viral or idiopathic acute pericarditis (<0.5%) but, in contrast, is relatively frequent for specific etiologies, especially bacterial.
authors.affiliation: Cardiology Department, Maria Vittoria Hospital, Torino, Italy. massimo_imazio@yahoo.it
authors.forename: Massimo
authors.initials: M
authors.lastname: Imazio
authors.forename: Antonio
authors.initials: A
authors.lastname: Brucato
authors.forename: Silvia
authors.initials: S
authors.lastname: Maestroni
authors.forename: Davide
authors.initials: D
authors.lastname: Cumetti
authors.forename: Riccardo
authors.initials: R
authors.lastname: Belli
authors.forename: Rita
authors.initials: R
authors.lastname: Trinchero
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Adler
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010493:Pericarditis / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D010494:Pericarditis, Constrictive / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D011446:Prospective Studies; D012307:Risk Factors