title: Impaired 6-min walk test, heart rate recovery and cardiac function post pulmonary embolism in long-term survivors.
abstract: BACKGROUND
  The functional capacity of long-term survivors of submassive pulmonary embolism (PE) is unreported. A six-minute walk distance (6MWD) <350 m and reduced heart rate recovery (HRR) indicate adverse prognosis in various chronic diseases.
  
  
  METHODS
  Long-term survivors of acute PE (January 2000-June 2005) were invited to undergo prospectively planned six-minute walk test (6MWT), transthoracic echocardiogram (TTE), clinical and biochemical evaluation with cardiac biomarkers. HRR was calculated as the difference between heart rate at 6-min during and at 1-min post 6MWT.
  
  
  RESULTS
  120 patients (52 males; mean age [±standard deviation] - 65 ± 14 years) were identified 7.7 ± 1.4 years after PE. 6MWD was significantly lower than that predicted after adjustment for age, sex, and height (448 ± 114 m vs 475 ± 89 m, p = 0.005), and 16% (17/104) had 6MWD <350 m. Among patients with no baseline comorbidities at follow-up (Charlson comorbidity index = 0), 8% (4/52) had 6MWD <350 m. Resting TTE identified 29% of patients had raised right ventricular (RV) pulmonary pressure (pulmonary arterial systolic pressure [PASP] >36 mmHg) and 13% had impaired RV function. Patients with 6MWD <85% predicted had significantly greater impairment of RV longitudinal function (p < 0.001), higher PASP (p < 0.001) and pulmonary vascular resistance (p < 0.001), elevated NT-proBNP (p = 0.03) and high-sensitivity troponin-T (HsTropT, p = 0.03), but similar left ventricular systolic and diastolic function, to those with normal 6MWT.
  
  
  CONCLUSIONS
  Apparently well, long-term survivors of PE demonstrate impaired exercise capacity, heart rate recovery, mild pulmonary hypertension, raised PVR and right ventricular dysfunction associated with elevated NT-proBNP and HsTropT.
authors.affiliation: ANZAC Research Institute, Sydney, Australia; Department of Cardiology, Concord Repatriation General Hospital and The University of Sydney, Sydney, Australia.
authors.forename: Vincent
authors.initials: V
authors.lastname: Chow
authors.affiliation: Department of Cardiology, Concord Repatriation General Hospital and The University of Sydney, Sydney, Australia.
authors.forename: Austin C C
authors.initials: AC
authors.lastname: Ng
authors.affiliation: Department of Thoracic Medicine, Concord Repatriation General Hospital and The University of Sydney, Australia.
authors.forename: Leigh
authors.initials: L
authors.lastname: Seccombe
authors.affiliation: Department of Cardiology, Concord Repatriation General Hospital and The University of Sydney, Sydney, Australia.
authors.forename: Tommy
authors.initials: T
authors.lastname: Chung
authors.affiliation: Department of Cardiology, Liverpool Hospital and University of New South Wales, Australia.
authors.forename: Liza
authors.initials: L
authors.lastname: Thomas
authors.affiliation: Department of Cardiology, Royal Prince Alfred Hospital and The University of Sydney, Australia.
authors.forename: David S
authors.initials: DS
authors.lastname: Celermajer
authors.affiliation: Department of Thoracic Medicine, Concord Repatriation General Hospital and The University of Sydney, Australia.
authors.forename: Matthew
authors.initials: M
authors.lastname: Peters
authors.affiliation: ANZAC Research Institute, Sydney, Australia; Department of Cardiology, Concord Repatriation General Hospital and The University of Sydney, Sydney, Australia. Electronic address: leonard.kritharides@sydney.edu.au.
authors.forename: Leonard
authors.initials: L
authors.lastname: Kritharides
mesh_terms: D000208:Acute Disease; D000368:Aged; D015415:Biomarkers / Q000097:blood; D004452:Echocardiography / Q000379:methods; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000097:blood / Q000150:complications*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000097:blood / Q000150:complications*; D018497:Ventricular Dysfunction, Right / Q000097:blood / Q000150:complications*
chemical_list: D015415:Biomarkers
keywords: Echocardiography; Functional assessment; Pulmonary embolism; Six minute walk test