Presentation Abstract

Session: P03-Biomarkers
Thursday, Mar 24, 2011, 5:00 PM - 7:00 PM
Presentation: P207 - A Single Bout of High-Intensity Interval Exercise May Decrease Blood Levels of Endothelial Microparticles in Coronary Heart Disease Patients
Location: P207
Pres. Time: Thursday, Mar 24, 2011, 5:00 PM - 7:00 PM
Category: +EPI - Biomarkers
Keywords: Exercise; Endothelial function; Coronary heart disease
Author(s): Thibaut Guiraud, Mathieu Gayda, Martin Juneau, Montreal Heart Inst, Montreal, QC, Canada; Laurent Bosquet, Dept of Sports Science, Univ of Poitiers, Poitiers, France; Philippe Meyer, Gabriel Théberge-Julien, Éric Rhéaume, Montreal Heart Inst, Montreal, QC, Canada; Anna Nozza, Montreal Heart Inst Coordinating Ctr, Montreal, QC, Canada; Jean-Claude Tardif, Anil Nigam, Montreal Heart Inst, Montreal, QC, Canada
Abstract: Background: We showed that a single bout of high-intensity interval exercise (HIIE) consisting of repeated 15-s intervals of exercise at 100% of peak power output (PPO) interspersed by recovery periods of equal duration, represents the optimal HIIE mode in CAD patients with respect to time spent near peak VO2, while being well-tolerated and more efficient than a maximal isocaloric continuous aerobic exercise (MICE). The mechanical constraints associated with HIIE, however, may generate abnormal levels of circulating endothelial microparticules (EMPs), a novel marker of endothelial injury and vascular damage. We tested the hypothesis that HIIE generates less EMPs than MICE, leading to a better safety profile assessed by monitoring cardiac ischemia and ECG parameters.
Method: Twenty patients with stable CAD (19 males, 1 female, 62 ± 11 years) were assigned in random order to a single session of HIIE as defined above, and to a MICE session corresponding to 70% of PPO. EMPs (CD31+ and/or CD62E/CD42b-), platelet microparticles (CD42b+), nitrates/nitrites, prostacycline and cardiac Troponin T (cTnT) were measured 10 min before exercise and 20 min, 24h and 72 h after both exercise sessions.
Results: No significant ventricular arrhythmias or abnormal blood pressure responses occurred during either exercise session. EMP parameters, nitrates/nitrites and prostacycline remained unchanged after exercise irrespective of type of session (HIIE vs. MICE). We found, however, an inverse relationship between the initial concentration of EMP and the exercise-induced reduction of EMP levels following the HIIE session (r=0.91, p<0.0001); in other words, the higher the initial concentration of EMP, the greater the reduction in circulating EMP levels following HIIE. Serum concentration of cTnT was normal in all participants at baseline and did not increase in the post-exercise period.
Conclusion: Our results suggests that a single bout of HIIE is safe, well-tolerated and may reduce endothelial microparticles, which is in favour of a better long-term safety profile associated with this paradigm of exercise training. These data support the need for future studies to determine whether a HIIE training program may be implemented into phase III cardiac rehabilitation.
Disclosures:  T. Guiraud: None. M. Gayda: None. M. Juneau: None. L. Bosquet: None. P. Meyer: None. G. Théberge-Julien: None. É. Rhéaume: None. A. Nozza: None. J. Tardif: None. A. Nigam: None.