Immediate Angiography or Wait Until the Next Working Day for Non-ST Elevation ACS?
Immediate Angiography or Wait Until the Next Working Day for Non-ST Elevation ACS?
Abstract & Commentary
By Andrew J. Boyle, MD, PhD, Assistant Professor of Medicine, Interventional Cardiology, University of California, San Francisco. Dr. Boyle reports no financial relationships relevant to this field of study. This article originally appeared in the November 2009 issue of Clinical Cardiology Alert. It was edited by Michael H. Crawford, MD, and peer reviewed by Ethan Weiss, MD. Dr. Crawford is Professor of Medicine, Chief of Cardiology, University of California, San Francisco, and Dr. Weiss is Assistant Professor of Medicine, Division of Cardiology and CVRI, University of California, San Francisco. Dr. Crawford is on the speaker's bureau for Pfizer, and Dr. Weiss reports no financial relationships relevant to this field of study.
Source: Montalescot, G et al. Immediate vs delayed intervention for acute coronary syndromes. A randomized clinical trial. JAMA. 2009;302:947-954.
Many clinical trials have confirmed the benefit of early invasive therapy for high-risk patients presenting with acute coronary syndromes (ACS). However, the optimal timing of cardiac catheterization in this group remains unknown. Whether they should go immediately to the cardiac catheterization laboratory, even in the middle of the night, as with ST elevation myocardial infarction, or wait until the next working day to go to the cath lab was the subject of this study. Thus, Montalescot et al performed a randomized, multicenter trial, the Angioplasty to Blunt the Rise of Troponin in Acute Coronary Syndromes Randomized for an Immediate or Delayed Intervention (ABOARD) study.
Thirteen centers in France enrolled patients presenting with ACS who were at moderate to high risk, as indicated by a TIMI risk score of 3 or more, and randomized them to immediate coronary angiography, with revascularization at the operator's discretion, vs. delaying the procedure until the next working day. Physicians were encouraged to perform percutaneous coronary intervention (PCI) at the same sitting, if possible, or coronary artery bypass graft surgery (CABG) as soon as possible for an inpatient. Exclusion criteria included refractory ischemia, arrhythmia, or hemodynamic instability requiring urgent cardiac catheterization, ongoing warfarin, fibrinolytic, or glycoprotein IIb/IIIa inhibitor use. All patients were loaded with high-dose aspirin (500 mg) and clopidogrel (≥ 300 mg); antithrombin use was at the physician's discretion. The primary endpoint was the peak troponin-I level during hospitalization. The key secondary endpoint was a composite of death, myocardial infarction (MI), or urgent revascularization at one month.
Baseline characteristics were well matched between patients undergoing immediate (n = 175) and delayed (n = 177) treatment. Mean age was 65 years, 72% were male, 27% had diabetes, and 74% had elevated troponin levels. Median time from randomization to sheath insertion was 70 minutes (interquartile range [IQR] 0.51-123) in the immediate group and 21 hours (IQR 18-25) in the delayed group. Radial arterial approach was used for coronary angiography in 84%, 74% went on to have PCI, and 11% had CABG. Two-thirds of patients received low molecular weight heparin, 2.9% of the immediate group and 0.6% of the delayed group received no anti-thrombin therapy, and abciximab was administered to 65.1% of the immediate group and 57.4% of the delayed group, but no statistical analysis of the rates between groups is given. Almost all patients received clopidogrel, but we are not told at what time during the hospitalization this was administered.
The primary endpoint of peak troponin level during hospitalization was similar in the two groups (2.1 [0.3-7.1] ng/mL vs. 1.7 [0.3-7.2] ng/mL in the immediate and delayed groups, respectively; p = 0.70). These results were similar when stratified by age, gender, diabetes, and TIMI risk score 5. The combined secondary endpoint was also similar between groups (13.7% [8.6-18.8%] vs. 10.2% [5.7-14.6%]; p = 0.31) in the immediate and delayed groups, respectively. Furthermore, the individual components of the combined secondary endpoint were also not significantly different between groups. Recurrent ischemia tended to be lower in the immediate group (12.0% [7.2-16.8%] vs. 18.6% [12.9-24.4%]; p = 0.08), and the rates of MI at 30 days tended to be higher in the immediate group (9.1% vs. 4.5%; p = 0.09), but these failed to reach statistical significance. Hospital stay was 22 hours shorter in the immediate group (55 hours [30-98] vs. 77 hours [49-145]; p < 0.001). There was no difference in bleeding outcomes between the two groups. Montalescot et al conclude that in patients with moderate- to high-risk non-ST elevation ACS, a strategy of immediate intervention compared with a strategy of intervention deferred to the next working day (mean 21 hours) did not result in a difference in MI, as defined by peak troponin levels.
Commentary
Montalescot et al have demonstrated that for patients presenting with high-risk non-ST elevation ACS, it is safe to wait until the next working day to perform coronary angiography. This study is congruent with prior studies investigating the optimal timing of intervention in patients undergoing early invasive strategy, such as the TIMACS study (Mehta et al. N Engl J Med. 2009;360: 2165-2175). Although practice patterns differ between centers and countries, this study adds more evidence that, despite slight differences in peri-procedural management, waiting until the next working day for an invasive strategy does not lead to worse patient outcomes. This study had relatively high rates of radial arterial access, high doses of clopidogrel, and relatively low rates of using direct thrombin inhibitors and glycoprotein IIb/IIIa inhibitors compared to practice in the United States. However, the medical management was exemplary, with high rates of statin, aspirin, and beta-blockers. Importantly, even the highest-risk patients, identified by a TIMI risk score greater than 5, did not benefit from earlier intervention. This study confirms that standard current practice patterns are indeed providing the best patient care.
Many clinical trials have confirmed the benefit of early invasive therapy for high-risk patients presenting with acute coronary syndromes (ACS). However, the optimal timing of cardiac catheterization in this group remains unknown.Subscribe Now for Access
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