Prospective Evaluation of the Strategy of Functionally Optimized Coronary Intervention (FCI)

Background
Long-term outcomes after percutaneous coronary intervention (PCI) relate in part to residual ischemia in the treated vessel as reflected in post-PCI fractional flow reserve (FFR). FFR post-PCI and treating residual ischemia, when appropriate, dubbed “functionally optimized coronary intervention” or FCI, may improve outcomes.

Methods
FCI was evaluated prospectively to determine the frequency of residual ischemia post-PCI and the ability to improve FFR with further intervention. Included were all PCI patients with lesions 50-99% and ischemic FFR (≤0.80) (NCT03227588).

Results
FCI strategy was attempted in 250 vessels in 206 consecutive patients. PCI success rate was 99.6% (249/250 vessels). FCI technical success, i.e. FFR pre- and post-PCI and PCI itself using the FFR wire, was 92% (230/250 vessels). Incidence of residual ischemia was 36.5%. Of the ischemic lesions undergoing further intervention (n=29), mean FFR increased from the ischemic to the non-ischemic range (0.71+0.07 to 0.81+0.06, p<0.001) and decreased vessels with residual ischemia to 30.4%. Pressure wire pullback showed FFR <0.8 at the distal stent edge was 7.9% and 0.7% proximal to the stent. FFR increase across the stent was larger in the ischemic than in the non-ischemic group [0.06(IQR 0.04-0.08) vs 0.03(IQR 0.01-0.05), p<0.0001] compatible with stent underexpansion as a contributor to residual ischemia.

Conclusions
Residual ischemia is frequent after PCI, located primarily distal to the stent and can be improved in a moderate percentage by further intervention. FCI appears to be a useful and feasible clinical strategy. Its effect on long-term outcomes needs further study.