Coronary Collateral Growth Induced by Physical Exercise: Results of the Leipzig EXerCIse Training versus MEdical Management in Patients With Stable Coronary Artery Disease (EXCITE) Trial
Background—A well-developed coronary collateral circulation provides a potential source of blood supply in coronary artery disease (CAD). However, the prognostic importance and functional relevance of coronary collaterals is controversial with the association between exercise training and collateral growth still unclear.
Methods and Results—This prospective, open-label study randomized 60 patients with significant CAD (FFR≤0.75) to high-intensity exercise (group A, 20 patients) or moderate-intensity exercise (group B, 20 patients) for 4 weeks or to a control group (group C, 20 patients). The primary endpoint was the change of the coronary collateral flow index (CFI) after 4 weeks. Analysis was based on the intention to treat. After 4 weeks, baseline CFI increased significantly by 39.4% in group A (from 0.142±0.07 at beginning to 0.198±0.09 at 4 weeks) compared to 41.3% in group B (from 0.143±0.06 to 0.202±0.09), whereas CFI in the control group remained unchanged (0.7%, from 0.149±0.09 to 0.150±0.08). High-intensity exercise did not lead to a greater CFI than moderate-intensity training. After 4 weeks, exercise capacity, V02 peak and ischemic threshold increased significantly in group A and group B as compared to group C with no difference between group A and group B.
Conclusions—A significant improvement in CFI was demonstrated in response to moderate- and high- intensity exercise performed for 10 hours per week.
Clinical Trial Registration Information—ClinicalTrials.gov. Identifier: NCT01209637.
- Received March 23, 2015.
- Revision received February 4, 2016.
- Accepted February 12, 2016.