May 21, 2014Circulation Cardiovascular Interventions193 citationsOpen Access
Prognosis of Patients With Non–ST-Segment–Elevation Myocardial Infarction and Nonobstructive Coronary Artery Disease
View Full Paper
Key Result
Nonobstructive CAD in patients with NSTE-ACS and elevated troponin was associated with higher 1-year mortality compared to obstructive CAD (5.2% vs 1.6%; HR 3.44; 95% CI 1.05-11.28; P=0.04).
Study Design
Type
Cohort (n=2,442)
Structured PICO
Does nonobstructive CAD compared to obstructive CAD affect 1-year mortality in patients with NSTE-ACS and elevated troponin?
P
Population
2,442 patients with non-ST-segment-elevation acute coronary syndromes and elevated troponin levels, followed for 1 year.
E
Exposure
Nonobstructive coronary artery disease (quantitative diameter stenosis ≤50%)
C
Comparator
Obstructive coronary artery disease (any lesion with quantitative diameter stenosis >50%)
O
Outcome
1-year mortalityhard clinical
Patients with NSTE-ACS and elevated troponin but nonobstructive CAD have a higher 1-year mortality risk, driven by noncardiac causes, compared to those with obstructive CAD.
Main Result
Hazard Ratio: 3.44 (95% CI 1.05–11.28)
Absolute Event Rate: 5.2% vs 1.6%
p-value: p=0.04
Abstract
BACKGROUND: Troponin elevation is a risk factor for mortality in patients with non-ST-segment-elevation acute coronary syndromes. However, the prognosis of patients with troponin elevation and nonobstructive coronary artery disease (CAD) is unknown. Our objective was therefore to evaluate the impact of nonobstructive CAD in patients with non-ST-segment-elevation acute coronary syndromes and troponin elevation enrolled in the Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) trial. METHODS AND RESULTS: In the ACUITY trial, 3-vessel quantitative coronary angiography was performed in a formal substudy of 6921 patients presenting with non-ST-segment-elevation acute coronary syndromes. Patients with elevated admission troponin levels were stratified by the presence or absence of obstructive CAD (any lesion with quantitative diameter stenosis >50%). Propensity score matching was performed to adjust for baseline characteristics. Of 2442 patients with elevated troponin, 197 (8.8%) had nonobstructive CAD. Maximum diameter stenosis was 87.4 (73.2, 100.0) versus 22.6 (19.2, 25.7; P<0.0001) in patients with versus without obstructive CAD, respectively. Propensity matching yielded 117 patients with nonobstructive CAD and 331 patients with obstructive CAD, with no significant baseline differences between groups. In the matched cohort, overall 1-year mortality was significantly higher in patients with nonobstructive CAD (5.2% versus 1.6%; hazard ratio 95% confidence interval=3.44 1.05, 11.28; P=0.04), driven by greater noncardiac mortality. Conversely, recurrent myocardial infarction and unplanned revascularization rates were significantly higher in patients with obstructive CAD. CONCLUSIONS: Patients with non-ST-segment-elevation acute coronary syndromes and elevated troponin levels but without obstructive CAD, while having low rates of subsequent myocardial infarction and unplanned revascularization, are still at considerable risk for 1-year mortality from noncardiac causes. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00093158.