title: [Non-invasive coronary flow reserve is an independent predictor of exercise capacity after acute anterior myocardial infarction].
abstract: BACKGROUND
  After acute myocardial infarction (MI) coronary microvascular impairment and reduced exercise capacity are both determinant of prognosis.
  
  
  OBJECTIVE
  We tested whether non-invasive coronary flow reserve (CFR) performed after MI predicts post-MI exercise capacity (EC).
  
  
  METHODS
  Fifty consecutive patients (pts) (mean age 56.5±11years, 30% women) with a first reperfused ST-elevation anterior MI, and sustained TIMI 3 flow after mechanical reperfusion, underwent prospectively non-invasive CFR in the distal part of the left anterior descending artery (LAD), using intravenous adenosine infusion (0.14mg/kg per minute, within 2min), within 24h after successful primary coronary angioplasty (CFR 1), and 4±1.6months later after a period of convalescence and a cardiac rehabilitation program (CFR 2). CFR was defined as peak hyperaemic LAD flow velocity divided by baseline flow velocity. All pts also underwent semi-supine exercise stress echocardiography (ESE) the same day of CFR 2. ESE was performed at an initial workload of 25-30watts with a 20watts increase at 2-minute intervals. Beta-blockers were withheld 24h before ESE.
  
  
  RESULTS
  The mean CFR 2 increased significantly when compared to CFR 1 (2.9±0.65 versus 1.9±0.4, P<0.01). During ESE, percentage of maximal predict heart rate achieved was 82±12%, maximal workload 95±30watts, exercise duration 486±155s, the ratio of double product 3.1±0.8, and EC 5.8±1.1 metabolic equivalents. No ischemia was induced during ESE in all pts, and the degree of mitral regurgitation did not differ significantly between rest and exercise. CFR 2 was significantly correlated to all indices related to EC (all, P<0.01), whereas CFR 1 was correlated to LV systolic function at follow-up (P<0.05) but not to EC. In multivariate analysis including age, sex, and body mass index, CFR 2 remained an independent predictor of EC (P<0.01).
  
  
  CONCLUSIONS
  Contrarily to acute CFR, CFR at follow-up is an independent predictor of EC after reperfused anterior MI. This suggests that the improvement of the coronary microcirculation is closely linked to the physical aptitude after MI.
authors.affiliation: Service de cardiologie et de soins intensifs, centre hospitalier de Compiègne, 8, rue Henri-Adnot, 60321 Compiègne, France. patrickmeimoun.md@gmail.com
authors.forename: P
authors.initials: P
authors.lastname: Meimoun
authors.forename: J
authors.initials: J
authors.lastname: Clerc
authors.forename: M
authors.initials: M
authors.lastname: Ghannem
authors.forename: A
authors.initials: A
authors.lastname: Neykova
authors.forename: B
authors.initials: B
authors.lastname: Tzvetkov
authors.forename: A-L
authors.initials: AL
authors.lastname: Germain
authors.forename: F
authors.initials: F
authors.lastname: Elmkies
authors.forename: H
authors.initials: H
authors.lastname: Zemir
authors.forename: A
authors.initials: A
authors.lastname: Luycx-Bore
mesh_terms: D000368:Aged; D000465:Algorithms; D056988:Anterior Wall Myocardial Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology; D025401:Echocardiography, Stress; D005080:Exercise Test; D005260:Female; D053805:Fractional Flow Reserve, Myocardial; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity