Although fractional flow reserve (FFR)-guided percutaneous-coronary-intervention (PCI)
has improved short- and middle-term outcome compared with angiography-guided PCI alone,
cardiac-events still occur in FFR-deferral patients in long-term.1-4 Recent J-CONFIRM
registry examined 1263 patients with 1447 lesions in whom revascularization was deferred
based on FFR in the 28 centers.5 While 2-year target vessel failure (TVF) rate was 5.5%
in deferred lesions in the J-CONFIRM registry, 5-year TVF raised up 11.6% in deferred
lesions.5, 6 The TVF rate raised up from 5.5% to 11.6% in the last 3 years mainly due to
clinically driven target-vessel-revascularization (TVR) in the registry.5, 6 In the DEFER
trial, patients with FFR > 0.75 were randomly assigned to PCI deferral (Defer) or
performance (Perform) and patients showing FFR < 0.75 underwent PCI (Reference).3 The
5-year cardiac death and acute myocardial infarction (AMI) rate were excellent in the
Defer group as compared to Perform and Reference groups (3.3%, 7.9%, and 15.7%, p <
0.003, respectively).4 However, 15-year follow-up of the DEFER study revealed that all
cause of mortality and TVR were similar among Defer, Perform and Reference groups
(mortality; 33.0% vs. 31.1% vs. 36.1% p= 0.441 respectively, and TVR; 36.3% vs. 27.8% vs.
35.4%, p= 0.522 respectively).7 Favorable initial 5-year clinical outcome in deferral
patients has been lost during 15-year follow-up in the DEFER study. It is urgent issue to
disclose the factor to predict future cardiac events in deferral lesions. The failure of
PCI to modify long-term outcomes may stem from its inability to modify the underlying
atherosclerotic process.
Furthermore, recent PREVENT study disclosed that in patients with non-flow-limiting (FFR
>0.80) vulnerable coronary plaques identified by intracoronary imaging, preventive PCI
reduced major adverse cardiac events (MACE) arising from high-risk vulnerable plaques,
compared with optimal medical therapy (OMT) alone8. Although their high-risk vulnerable
plaques were defined using intracoronary imaging but not coronary CT angiography (CTA) in
the PREVENT study, the presence of high-risk vulnerable plaque without flow-limiting (FFR
>0.80) frequently caused the subsequent cardiac events in patients without the initial
PCI.
While CTA is known to be useful to evaluate coronary artery plaque features as well as
stenosis severity, high-risk plaque (HRP) on coronary CTA defined as a combination of
positive remodeling (PR) and low attenuation plaque (LAP) has been reported to be
associated with the future cardiac events.9-12 Gallone and coworkers reported in their
meta-analysis that high-risk coronary plaque characteristics significantly predicted
patient-level and lesion-level major adverse cardiac event (MACE) in the future, using
various high-risk coronary plaque definitions by several intracoronary imaging modalities
and CTA.13 The investigators hypothesized that CTA could identify plaque features linked
to future cardiac events in deferral patients. To determine the predictive factors for
future cardiac events in FFR-based deferral patients, the investigators examined clinical
features and plaque characteristics on CTA in the deferral lesions based on invasive FFR
in consecutive 373 patients with chronic coronary syndromes (CCS).