January 8, 2024Open Access
Factors associated with early, late, and very late stent thrombosis among patients with acute coronary syndrome undergoing coronary stent placement: analysis from the ATLAS ACS 2-TIMI 51 trial
Key Result
Rivaroxaban therapy significantly reduced the risk of overall stent thrombosis by 37.5% (HR 0.625) up to 720 days compared to placebo in patients with acute coronary syndrome undergoing coronary stent placement.
Study Design
Type
RCT (n=8,741)
Blinding
Double-blind
Randomization
1:1:1
Multicenter
Yes
Structured PICO
What clinical and laboratory factors are associated with early, late, and very late stent thrombosis in patients with acute coronary syndrome undergoing coronary stent placement?
P
Population
8,741 patients who received coronary stent placement during percutaneous coronary intervention for an index acute coronary syndrome (ACS) enrolled in the ATLAS ACS 2-TIMI 51 trial. Mean age ~61.8 years, ~79% male. Key inclusion: ACS presentation within 7 days of hospital admission. Excluded: history of prior coronary stent implantation.
I
Intervention
Rivaroxaban 2.5 mg or 5.0 mg oral twice daily added to standard medical therapy (low-dose aspirin and a thienopyridine [clopidogrel or ticlopidine])
C
Comparator
Matching placebo added to standard medical therapy (low-dose aspirin and a thienopyridine)
O
Outcome
Stent thrombosis (ST) classified as definite, probable, or possible based on Academic Research Consortium (ARC) definitions, assessed at 30 days (early ST), 31-360 days (late ST), 361-720 days (very late ST), and up to 720 dayshard clinical
Readily available clinical and laboratory parameters, including age ≥75, prior MI, low hemoglobin, and high WBC count, are independently associated with an increased risk of stent thrombosis in ACS patients.
Main Result
Effect estimate: HR 0.625 (95% CI 0.443-0.882)
p-value: p=0.0075
Limitations
- Only 155 adjudicated ST events occurred through the end of follow-up, meaning landmark analyses may be underpowered.
- Maximum follow-up was 31 months, which may be inadequate for analyzing very late ST.
- Information about DAPT interruption was not available for analysis.
- Established lesion-, device-, and procedure-related risk factors (e.g., angiographic characteristics, stent dimensions) were not included.
- Incidence of early ST might have been underestimated as acute ST events prior to study enrollment were not accounted for.
- Incorporating possible ST into the analysis could have introduced diagnostic uncertainties.
- Post hoc exploratory analysis of a subset of stented ACS patients, so findings do not establish causality.
Abstract
Background: Stent thrombosis (ST) is an uncommon but serious complication of stent implantation. This study aimed to explore factors associated with early, late, and very late ST to help guide risk assessment and clinical decision-making on ST. Methods: The analysis included patients who received stent placement for the index acute coronary syndrome (ACS). Cumulative incidence of ST was assessed at 30 days (early ST), 31-360 days (late ST), 361-720 days (very late ST), and up to 720 days. Cox proportional hazards models were used to assess associations between ST and various factors, including patient characteristics i.e., age, sex, ACS presentation, history of hypertension, smoking, diabetes, prior myocardial infarction (MI), heart failure, prior ischemic stroke, and cancer, laboratory tests i.e., positive cardiac biomarker, hemoglobin, platelet count, white blood cell (WBC) count, and treatment i.e., drug-eluting stent (DES) vs. bare-metal stent (BMS) and anticoagulant with rivaroxaban vs. placebo. Results: Among the 8,741 stented patients, 155 ST events (2.25%) occurred by Day 720. The cumulative incidences of early, late, and very late ST were 0.80%, 0.81%, and 0.77%, respectively. After multivariable adjustment, age ≥ 75 hazard ratio (HR) = 2.13 (95% confidence interval, CI: 1.26-3.60), a history of prior MI HR = 1.81 (95% CI: 1.22-2.68), low hemoglobin level HR = 2.34 (95% CI: 1.59-3.44), and high WBC count HR = 1.58 (95% CI: 1.02-2.46) were associated with a greater risk of overall ST, whereas DES HR = 0.56 (95% CI: 0.38-0.83) and rivaroxaban therapy HR = 0.63 (95% CI: 0.44-0.88) were associated with a lower risk of overall ST up to 720 days. Low hemoglobin level and high WBC count were associated with early ST (low hemoglobin: HR = 2.35 95% CI: 1.34-4.12; high WBC count: HR = 2.11 95% CI: 1.17-3.81). Low hemoglobin level and prior MI were associated with a greater risk of late ST (low hemoglobin: HR = 2.32 95% CI: 1.26-4.27; prior MI: HR = 2.98 95% CI: 1.67-5.31), whereas DES was associated with a lower risk of late ST HR = 0.33 (95% CI: 0.16-0.67). Age ≥75 years was associated with very late ST. Conclusion: The study identified positive and negative associations with early, late, and very late ST. These variables may be useful in constructing risk assessment models for ST. Clinical Trial Registration: http://www.clinicaltrials.gov, identifier NCT00809965.
Cite This Study
Chi et al. (Mon,) conducted a rct in Acute coronary syndrome (ACS) undergoing coronary stent placement (n=8,741). Rivaroxaban vs. Placebo was evaluated on Stent thrombosis (ST) up to 720 days (HR 0.625, 95% CI 0.443-0.882, p=0.0075). Rivaroxaban therapy significantly reduced the risk of overall stent thrombosis by 37.5% (HR 0.625) up to 720 days compared to placebo in patients with acute coronary syndrome undergoing coronary stent placement.