Intense Exercise and Native Collateral Function in Stable Moderate Coronary Artery Disease: Incidental, Causal or Clinically Important?
In the report by Uhlemann and colleagues in this issue of Circulation1, 60 patients with CAD by angiogram and FFR ≤ 0.75 were randomized to supervised high or moderate intensity exercise or a sedentary group for four weeks at specialized rehabilitation centers. At angiogram, a coronary artery was occluded by low pressure balloon occlusion for one minute without therapeutic percutaneous coronary intervention (PCI). The coronary pressure beyond the occlusion as a ratio to aortic pressure is an index of collateral back perfusion distal to the occlusion termed the Collateral Flow Index or CFI although flow is not measured, only pressure. Both high and moderate intensity training significantly improved CFI and exercise threshold for angina compared to the sedentary subjects. While collaterals on angiogram were not expressly addressed, the moderate, non-occlusive stenosis did not cause reported visible collaterals on angiogram thereby implying improved native micro-collaterals as the mechanism attributed to improved exercise performance.
- Received February 29, 2016.
- Revision received March 14, 2016.
- Accepted March 14, 2016.