Plaque Features and Residual Disease

Evidence

This retrospective observational pilot study was conducted at a tertiary care center among highly selected patients presenting with ST-elevation myocardial infarction who underwent primary percutaneous coronary intervention and culprit-lesion optical coherence tomography evaluation. From April 2023 through March 2024, 142 patients with ST-elevation myocardial infarction were screened and 30 met all eligibility criteria. The cohort had a mean age of 54.5 ± 10.1 years, and 25 patients were male (83.3%). The design therefore examined a selected subset rather than all patients presenting with ST-elevation myocardial infarction during the screening period. pmid:42934820

Optical coherence tomography imaging of the culprit lesion used the C7-XR/ILUMIEN system and Dragonfly catheter from Abbott. Investigators determined the residual SYNTAX score after percutaneous coronary intervention from completion angiograms. They classified patients by culprit-lesion thin-cap fibroatheroma status and a residual SYNTAX score threshold of 4: group 0 had no thin-cap fibroatheroma and a score greater than 4; group 1 had no thin-cap fibroatheroma and a score of 4 or less; group 2 had thin-cap fibroatheroma and a score greater than 4; and group 3 had thin-cap fibroatheroma and a score of 4 or less. Culprit-lesion thin-cap fibroatheroma was present in 16 of 30 patients (53.3%). pmid:42934820

The primary endpoint was cumulative major adverse cardiac events assessed at 1, 2, and 3 months. The composite comprised all-cause death, recurrent myocardial infarction, target lesion revascularization, heart failure hospitalization, and ischemic stroke. At least two independent cardiologists adjudicated all events. Thus, the study measured a short-term composite clinical endpoint after the index intervention while comparing four anatomy-and-plaque-characteristic strata; it did not report a multivariable predictive model because subgroup sizes were small. pmid:42934820

The overall cumulative 3-month major adverse cardiac event rate was 9 of 30 patients (30.0%). Across the four prespecified strata, major adverse cardiac events occurred in 1 of 7 patients (14.3%) in group 0, 1 of 7 (14.3%) in group 1, 4 of 11 (36.4%) in group 2, and 3 of 5 (60.0%) in group 3. The four-group Fisher exact comparison had P = 0.23, and the log-rank test for cumulative survival had P = 0.38. These reported comparisons were not statistically significant in the supplied results. pmid:42934820

When groups were combined by culprit-lesion thin-cap fibroatheroma status, major adverse cardiac events occurred in 7 of 16 patients with thin-cap fibroatheroma (43.8%) and 2 of 14 patients without thin-cap fibroatheroma (14.3%). This is a descriptive comparison of event frequencies within the selected cohort. The residual SYNTAX score strata provided the comparator structure, but the observed event counts were sparse, including only five patients in group 3. The reported numerical pattern therefore needs to be read alongside the formal four-group tests and the study’s stated exploratory purpose. pmid:42934820

Analysis — Observed Short-Term Risk Pattern

The observed pattern is consistent with the study’s retrospective selection process: patients with culprit-lesion thin-cap fibroatheroma had a higher descriptive 3-month major adverse cardiac event frequency than those without it, and the two thin-cap fibroatheroma groups had higher event frequencies than the two groups without thin-cap fibroatheroma. The comparison does not isolate the contribution of plaque morphology from residual coronary disease, patient characteristics, procedural factors, or other factors that may differ among the four groups. In particular, the equal 14.3% frequencies in the two groups without thin-cap fibroatheroma contrast with 36.4% and 60.0% in the groups with thin-cap fibroatheroma, but those values arise from group denominators of 7, 7, 11, and 5 patients. pmid:42934820

The results describe a combined anatomical-biological stratification rather than demonstrating that either measurement independently predicts events. The non-significant Fisher exact and log-rank results leave substantial uncertainty around between-group differences, and statistical significance is not a measure of clinical significance. Because events were adjudicated and the endpoint components were specified, the study offers a defined account of what was measured; however, its short three-month observation window confines the reported association to that period and selected population. pmid:42934820

Limitations

The retrospective design cannot establish causation. The investigators described clear selection bias and an atypical clinical event rate in this highly selected cohort. Selection began with 142 screened patients but included only 30 who met eligibility criteria and underwent culprit-lesion optical coherence tomography, so the comparison groups do not represent an unselected population of patients with ST-elevation myocardial infarction. The study compared groups defined jointly by residual SYNTAX score category and culprit-lesion thin-cap fibroatheroma status, rather than randomized groups. pmid:42934820

Small subgroup sizes limit precision and make individual event counts influential: all four groups contained fewer than 12 patients. The authors did not perform multivariable predictive risk modeling because of those subgroup sizes. The reported P values were not statistically significant, and the authors characterized the findings as strictly hypothesis-generating rather than as establishing independent prognostic value. Follow-up ended at three months, so the report describes short-term cumulative major adverse cardiac events rather than longer-term patterns. pmid:42934820

The outcome was a composite of several clinical events, while the principal descriptive comparison aggregated that composite by thin-cap fibroatheroma status. The source reports the component outcome definitions and group event counts, but the aggregate result cannot determine which component accounted for the observed difference between the combined thin-cap fibroatheroma groups and the groups without thin-cap fibroatheroma. The reported association should consequently remain scoped to the measured composite outcome, selected tertiary-care cohort, optical coherence tomography and angiographic classification methods, and three-month follow-up period. pmid:42934820