title: Six-minute walking test but not ejection fraction predicts mortality in elderly patients undergoing cardiac rehabilitation following coronary artery bypass grafting.
abstract: BACKGROUND
  Age-related effects on the ability of 6-min walking test (6MWT) and ejection fraction (EF) to predict mortality in coronary artery bypass grafting (CABG) patients undergoing cardiac rehabilitation (CR) is still debated.
  
  
  METHODS
  In order to verify the role of 6MWT and EF on all-cause mortality in patients undergoing CR following CABG, 882 CABG patients undergoing CR stratified in adults (<65 years) and elderly (≥65 years) were studied.
  
  
  RESULTS
  At the admission, EF was 52.6 ± 9.1% in adults and 51.3 ± 8.9% in elderly (p = 0.234, NS) while 6MWT was 343.8 ± 93.5 m in adults and 258.9 ± 95.7 m in elderly (p < 0.001). After 42.9 ± 14.1 months follow up, mortality was 8.2% in adults and 10.9% in elderly (p = 0.176, NS). Cox regression analysis shows that EF ≥ 50% and 6MWT ≥300 m are protective on mortality in all CABG patients before CR. However, EF ≥50% in adults (HR 0.18, 95% CI 0.06-0.49, p < 0.005) but not in elderly (HR 1.16, 95% CI 0.45-3.42, p = 0.354, NS) and 6MWT ≥300 m in elderly (HR 0.34, 95% CI 0.10-0.79, p = 0.033) but not in adults (HR 0.76, 95% CI 0.31-2.12, p = 0.654, NS) exert a protective role on mortality.
  
  
  CONCLUSIONS
  Our results indicate that both EF ≥ 50% and 6MWT ≥ 300 m independently protect against mortality in CABG patients before CR. However, their protective role is age dependent. In fact, EF ≥ 50% is protective in adults but not in elderly while 6MWT ≥ 300 m is protective in elderly but not in adult patients.
authors.affiliation: Dipartimento di Medicina Clinica e Scienze, Cardiovascolari ed Immunologiche, Cattedra di Geriatria, University of Naples Federico II, Naples, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Cacciatore
authors.forename: Pasquale
authors.initials: P
authors.lastname: Abete
authors.forename: Francesca
authors.initials: F
authors.lastname: Mazzella
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Furgi
authors.forename: Antonio
authors.initials: A
authors.lastname: Nicolino
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Longobardi
authors.forename: Gianluca
authors.initials: G
authors.lastname: Testa
authors.forename: Assunta
authors.initials: A
authors.lastname: Langellotto
authors.forename: Teresa
authors.initials: T
authors.lastname: Infante
authors.forename: Claudio
authors.initials: C
authors.lastname: Napoli
authors.forename: Nicola
authors.initials: N
authors.lastname: Ferrara
authors.forename: Franco
authors.initials: F
authors.lastname: Rengo
mesh_terms: D000367:Age Factors; D000368:Aged; D016009:Chi-Square Distribution; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000401:mortality*; D003324:Coronary Artery Disease / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000534:rehabilitation* / Q000601:surgery*; D005080:Exercise Test; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D013318:Stroke Volume; D016896:Treatment Outcome; D016138:Walking