title: Incidence of chronic thromboembolic pulmonary hypertension after pulmonary embolism.
abstract: BACKGROUND
  Chronic thromboembolic pulmonary hypertension (CTPH) is associated with considerable morbidity and mortality. Its incidence after pulmonary embolism and associated risk factors are not well documented.
  
  
  METHODS
  We conducted a prospective, long-term, follow-up study to assess the incidence of symptomatic CTPH in consecutive patients with an acute episode of pulmonary embolism but without prior venous thromboembolism. Patients with unexplained persistent dyspnea during follow-up underwent transthoracic echocardiography and, if supportive findings were present, ventilation-perfusion lung scanning and pulmonary angiography. CTPH was considered to be present if systolic and mean pulmonary-artery pressures exceeded 40 mm Hg and 25 mm Hg, respectively; pulmonary-capillary wedge pressure was normal; and there was angiographic evidence of disease.
  
  
  RESULTS
  The cumulative incidence of symptomatic CTPH was 1.0 percent (95 percent confidence interval, 0.0 to 2.4) at six months, 3.1 percent (95 percent confidence interval, 0.7 to 5.5) at one year, and 3.8 percent (95 percent confidence interval, 1.1 to 6.5) at two years. No cases occurred after two years among the patients with more than two years of follow-up data. The following increased the risk of CTPH: a previous pulmonary embolism (odds ratio, 19.0), younger age (odds ratio, 1.79 per decade), a larger perfusion defect (odds ratio, 2.22 per decile decrement in perfusion), and idiopathic pulmonary embolism at presentation (odds ratio, 5.70).
  
  
  CONCLUSIONS
  CTPH is a relatively common, serious complication of pulmonary embolism. Diagnostic and therapeutic strategies for the early identification and prevention of CTPH are needed.
authors.affiliation: Department of Clinical and Experimental Medicine, Division of Clinical Cardiology, University Hospital of Padua, Padua, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Pengo
authors.forename: Anthonie W A
authors.initials: AW
authors.lastname: Lensing
authors.forename: Martin H
authors.initials: MH
authors.lastname: Prins
authors.forename: Antonio
authors.initials: A
authors.lastname: Marchiori
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Davidson
authors.forename: Francesca
authors.initials: F
authors.lastname: Tiozzo
authors.forename: Paolo
authors.initials: P
authors.lastname: Albanese
authors.forename: Alessandra
authors.initials: A
authors.lastname: Biasiolo
authors.forename: Cinzia
authors.initials: C
authors.lastname: Pegoraro
authors.forename: Sabino
authors.initials: S
authors.lastname: Iliceto
authors.forename: Paolo
authors.initials: P
authors.lastname: Prandoni
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002908:Chronic Disease; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006976:Hypertension, Pulmonary / Q000453:epidemiology / Q000209:etiology*; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000150:complications*; D012008:Recurrence; D012307:Risk Factors; D013923:Thromboembolism / Q000150:complications