Prevalence and anatomical factors associated with stent under-expansion in non-severely calcified lesions.

BACKGROUND: Stent underexpansion, typically related to lesion calcification, is the strongest predictor of adverse events after percutaneous coronary intervention (PCI). Although uncommon, underexpansion may also occur in non-severely calcified lesions. AIM: We sought to identify the prevalence and anatomical characteristics of underexpansion in non-severely calcified lesions. METHODS: We included 993 patients who underwent optical coherence tomography-guided PCI of 1051 de novo lesions with maximum calcium arc <180°. Negative remodeling (NR) was the smallest lesion site external elastic lamina diameter that was also smaller than the distal reference. Stent expansion was evaluated using a linear regression model accounting for vessel tapering; underexpansion required both stent expansion <70% and stent area <4.5mm2. RESULTS: Underexpansion was observed in 3.6% of non-heavily calcified lesions (38/1051). Pre-stent maximum calcium arc and thickness were greater in lesions with versus without underexpansion (median 119° vs. 85°, p = 0.002; median 0.95 mm vs. 0.78 mm, p = 0.008). NR was also more common in lesions with underexpansion (44.7% vs. 24.5%, p = 0.007). In the multivariable logistic regression model, larger and thicker eccentric calcium, mid left anterior descending artery (LAD) location, and NR were associated with underexpansion in non-severely calcified lesions. The rate of underexpansion was especially high (30.7%) in lesions exhibiting all three morphologies. Two-year TLF tended to be higher in underexpanded versus non-underexpanded stents (9.7% vs. 3.7%, unadjusted hazard ratio [95% confidence interval] = 3.02 [0.92, 9.58], p = 0.06). CONCLUSION: Although underexpansion in the absence of severe calcium (<180°) is uncommon, mid-LAD lesions with NR and large and thick eccentric calcium were associated with underexpansion.

Impact of Eruptive vs Noneruptive Calcified Nodule Morphology on Acute and Long-Term Outcomes After Stenting.

BACKGROUND: Whether an eruptive or noneruptive target lesion calcified nodule (CN) portends worse acute and long-term clinical outcomes after stenting has not been established. OBJECTIVES: The authors sought to compare acute and long-term clinical outcomes in eruptive CN vs noneruptive CN morphology. METHODS: Using optical coherence tomography, an eruptive CN was defined as an accumulation of small calcium fragments protruding and disrupting the overlying fibrous cap, typically with small amount of thrombus. A noneruptive CN was defined as an accumulation of small calcium fragments with a smooth intact fibrous cap without an overlying thrombus. The primary endpoint was target lesion failure (TLF) including cardiac death, target vessel myocardial infarction, or clinically driven target lesion revascularization in patients with ≥6-month follow-up. RESULTS: Among 3,231 patients with evaluable pre- and postintervention OCT, 236 patients had lesions with CNs (7.3%). After eliminating 4 secondary lesions and 6 patients without ≥6-month follow-up, 126 (54.8%) lesions with eruptive CNs and 104 (45.2%) lesions with noneruptive CNs formed the current report. Compared with noneruptive CNs, eruptive CNs were independently associated with greater stent expansion (89.2% ± 18.7% vs. 81.5% ± 18.9%; P = 0.003) after adjusting for morphologic and procedural factors. At 2 years, eruptive CNs trended toward more TLF compared with noneruptive CNs (Kaplan-Meier estimates, 19.8% vs 12.5%; P = 0.11) and significantly more target lesion revascularization (18.3% vs 9.6%; P = 0.04). In the adjusted model, eruptive CNs were independently associated with 2-year TLF (HR: 2.07; 95% CI: 1.01-4.50; P = 0.048). CONCLUSIONS: Compared with noneruptive CN morphology, lesions with an eruptive CN appearance on optical coherence tomography had a worse poststent long-term clinical outcome despite better acute stent expansion.