Impact of absolute stent expansion on two-year clinical outcomes after PCI in patients with acute coronary syndrome: Results from the OCT-guided PCI registry (TACTICS registry).

BACKGROUND

Stent expansion is a crucial determinant of chronic coronary syndrome outcomes; however, its clinical impact and factors limiting optimal expansion in acute coronary syndrome (ACS) treated with optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) remain unclear.

METHODS

This post-hoc analysis of the prospective, multicenter TACTICS registry included 581 patients with OCT-identified atherothrombotic ACS. Suboptimal OCT findings were defined as minimum stent area (MSA) ≤ 4.5 mm2, MSA < 70% of the mean reference lumen area, reference lumen narrowing, stent-edge dissection, stent malapposition, or tissue protrusion. The primary endpoint was 2-year device-oriented cardiovascular events (DoCE)-cardiovascular death, target-vessel myocardial infarction (TVMI), or ischemia-driven target lesion revascularization (TLR)-adjudicated by an independent committee.

RESULTS

DoCE occurred in 5.3% of patients, and among suboptimal OCT parameters, only MSA ≤ 4.5 mm2 was associated with DoCE (hazard ratio, 2.31; 95% confidence interval 1.14-4.68; P = 0.020). Patients with MSA ≤ 4.5 mm2 had a higher incidence of DoCE than those with MSA > 4.5 mm2 (8.9% vs. 4.0%; log-rank P = 0.017), mainly driven by ischemia-driven TLR (5.1% vs. 1.9%; log-rank P = 0.032), with a trend toward higher incidence of TVMI (2.5% vs. 0.7%; log-rank P = 0.069). In multivariable logistic regression analysis, independent predictors of MSA ≤ 4.5 mm2 were smaller distal reference lumen area, maximum calcium arc ≥180°, and non-ST-segment elevation myocardial infarction.

CONCLUSION

In patients with ACS undergoing OCT-guided PCI, an MSA ≤ 4.5 mm2 was independently associated with higher DoCE risk. Predictors of suboptimal stent expansion may underlie the increased risk of adverse outcomes despite OCT guidance.

CLINICAL TRIAL REGISTRATION: URL: https://www.umin.ac.jp/ctr/index.htm; unique identifier: UMIN000039050.