title: Coronary artery pattern and age impact exercise performance late after the arterial switch operation.
abstract: OBJECTIVE
  The impact of coronary artery pattern on exercise performance after the arterial switch operation is unknown. The purpose of this study was to evaluate the relationship between coronary artery pattern and exercise performance late after the arterial switch operation.
  
  
  METHODS
  Patients who underwent the arterial switch operation and were referred for exercise stress testing between January of 1996 and April of 2005 were included. Univariate and multivariate analyses were performed to identify risk factors for lower maximum heart rate and percent of predicted peak oxygen consumption.
  
  
  RESULTS
  Fifty-three patients were included; 72% were male. The median age at the arterial switch operation was 5 days (1 day to 3.6 years); 32% had concurrent ventricular septal defect repair. The time from the arterial switch operation to exercise stress testing was 14.1 years (7.7-20.6 years). There were 37 patients with the usual coronary artery pattern, and 16 patients (30%) with variant coronary artery patterns. At exercise stress testing, there was no difference in respiratory exchange ratio (1.16 +/- 0.1 for both), indicating similar effort. Compared with patients with the usual coronary artery pattern, patients with variant coronary artery patterns had a significantly lower maximum heart rate (177 +/- 16 beats/min [89% predicted] vs 186 +/- 11 beats/min [93% predicted], respectively, P = .04). Percent of predicted peak oxygen consumption was not significantly different between patients with the usual coronary pattern and patients with variant coronary artery patterns (89% +/- 20% vs 80% +/- 17%, respectively, P = .12). In multivariate analysis, variant coronary artery patterns (P = .03) and ventricular septal defect (P = .004) were predictors of significantly lower maximum heart rate and were associated with a trend toward lower percent of predicted peak oxygen consumption (P < .09). Longer follow-up time was the strongest predictor of lower percent of predicted peak oxygen consumption (P < .001).
  
  
  CONCLUSIONS
  Variant coronary artery patterns are associated with chronotropic impairment, and longer follow-up time is the strongest predictor of diminished aerobic capacity late after arterial switch operation.
authors.affiliation: The Cardiac Center at The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pa 19104, USA.
authors.forename: Sara K
authors.initials: SK
authors.lastname: Pasquali
authors.forename: Bradley S
authors.initials: BS
authors.lastname: Marino
authors.forename: Michael G
authors.initials: MG
authors.lastname: McBride
authors.forename: Gil
authors.initials: G
authors.lastname: Wernovsky
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Paridon
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D013504:Cardiovascular Surgical Procedures; D002648:Child; D002675:Child, Preschool; D003331:Coronary Vessels; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D010101:Oxygen Consumption; D014188:Transposition of Great Vessels / Q000503:physiopathology* / Q000601:surgery*