title: Coronary flow reserve is supranormal in endurance athletes: an adenosine transthoracic echocardiographic study.
abstract: OBJECTIVE
  To compare coronary flow reserve in endurance athletes and healthy sedentary controls, using adenosine transthoracic echocardiography.
  
  
  METHODS
  29 male endurance athletes (mean (SD) age 27.3 (6.6) years, body mass index (BMI) 22.1 (1.9) kg/m(2)) and 23 male controls (age 27.2 (6.1) years, BMI 23.9 (2.6) kg/m(2)) with no coronary risk factors underwent transthoracic echocardiographic assessment of distal left anterior descending coronary artery (LAD) diameter and flow, both at rest and during intravenous adenosine infusion (140 microg/kg/min).
  
  
  RESULTS
  Distal LAD diameter and flow were adequately assessed in 19 controls (83%) and 26 athletes (90%). Distal LAD diameter in athletes (2.04 (0.25) mm) was not significantly greater than in sedentary controls (1.97 (0.27) mm). Per cent increase in LAD diameter following 400 microg sublingual nitrate was greater in the athletes than in the controls, at 14.1 (7. 2)% v 8.8 (5.7)% (p < 0.01). Left ventricular mass index in athletes exceeded that of controls, at 130 (19) v 98 (14) g/m(2) (p < 0.01). Resting flow among the athletes (10.6 (3.1) ml/min; 4.4 (1.2) ml/min/100 g left ventricular mass) was less than in the controls (14.3 (3.6) ml/min; 8.2 (2.2) ml/min/100 g left ventricular mass) (both p < 0.01). Hyperaemic flow among the athletes (61.9 (17.8) ml/min) exceeded that of the controls (51.1 (14.6) ml/min; p = 0.02), but not when corrected for left ventricular mass (25.9 (5.6) v 28.5 (7.4) ml/min/100 g left ventricular mass; NS). Coronary flow reserve was therefore substantially greater in the athletes than in the controls, at 5.9 (1.0) v 3.7 (0.7) (p < 0.01).
  
  
  CONCLUSIONS
  Coronary flow reserve in endurance athletes is supranormal and endothelium independent vasodilatation is enhanced. Myocardial hypertrophy per se does not necessarily impair coronary flow reserve. Adenosine transthoracic echocardiography is a promising technique for the investigation of coronary flow reserve.
authors.affiliation: Cardiac Unit, Papworth Hospital, Cambridge CB3 8RE, UK. david.hildick-smith@papworth-tr.anglox.nhs.uk
authors.forename: D J
authors.initials: DJ
authors.lastname: Hildick-Smith
authors.forename: P J
authors.initials: PJ
authors.lastname: Johnson
authors.forename: C R
authors.initials: CR
authors.lastname: Wisbey
authors.forename: E M
authors.initials: EM
authors.lastname: Winter
authors.forename: L M
authors.initials: LM
authors.lastname: Shapiro
mesh_terms: D000241:Adenosine; D000328:Adult; D001783:Blood Flow Velocity; D016022:Case-Control Studies; D003326:Coronary Circulation / Q000502:physiology*; D003331:Coronary Vessels / Q000033:anatomy & histology; D004452:Echocardiography; D004730:Endothelium, Vascular / Q000187:drug effects; D006801:Humans; D008297:Male; D010807:Physical Endurance / Q000502:physiology*; D013177:Sports / Q000502:physiology*; D014665:Vasodilator Agents
chemical_list: D014665:Vasodilator Agents; D000241:Adenosine